Minneapolis Park & Recreation Board WATER RESOURCES REPORT 2015

Environmental Management February 2017

2015 WATER RESOURCES REPORT

Prepared by:

Minneapolis Park & Recreation Board Environmental Stewardship 3800 Bryant Avenue South Minneapolis, MN 55409-1029 612.230.6400 www.minneapolisparks.org

March 2017

Funding provided by:

Minneapolis Park & Recreation Board

City of Minneapolis Public Works

Copyright © 2017 by the Minneapolis Park & Recreation Board Material may be quoted with attribution.

TABLE OF CONTENTS Page

Abbreviations ...... i Executive Summary ...... iv

1. Monitoring Program Overview ...... 1-1 2. Birch Pond ...... 2-1 3. Brownie Lake ...... 3-1 4. Lake Calhoun ...... 4-1 5. Cedar Lake ...... 5-1 6. Diamond Lake ...... 6-1 7. Grass Lake ...... 7-1 8. Lake Harriet ...... 8-1 9. Lake Hiawatha ...... 9-1 10. Lake of the Isles ...... 10-1 11. Loring Pond ...... 11-1 12. Lake Nokomis ...... 12-1 13. Powderhorn Lake ...... 13-1 14. Ryan Lake ...... 14-1 15. Spring Lake ...... 15-1 16. Webber NSP ...... 16-1 17. Wirth Lake ...... 17-1 18. Comparisons Among Lakes ...... 18-1 19. Public Beach Monitoring ...... 19-1 20. Aquatic Plant Management ...... 20-1 21. Wetland Health Evaluation Program (WHEP) ...... 21-1 22. National Pollutant Discharge Elimination System (NPDES) Monitoring ...... 22-1 23. 37th Greenway Parallel SAFL ...... 23-1 24. 37th Greenway Iron Enhanced Filter ...... 24-1 25. 37th and Oliver Flood Relief Vault ...... 25-1 26. Webber Stormwater Pond ...... 26-1 27. Lyndale Dog Park ...... 27-1 28. Golf Course Wetland Monitoring ...... 28-1 29. Climatological Summary ...... 29-1 30. Water Quality Education ...... 30-1 31. Quality Assurance Assessment Report ...... 31-1 32. Additional Sources of Water Quality Information ...... 32-1 33. References ...... 33-1

Appendix A – Box and Whisker Plot Record ...... A-1 Appendix B – Lake Monitoring Data 2015 ...... B-1

2015 Water Resources Report – Minneapolis Park & Recreation Board LIST OF ABBREVIATIONS

% DO Percent Dissolved Oxygen µg Microgram µm Micrometer µmhos Micromhos µS Micro Siemens ACSP Audubon Cooperative Sanctuary Program Al Aluminum Alk Alkalinity alum Aluminum sulfate As Arsenic BCWMC Bassett's Creek Watershed Management Commission BMP Best Management Practices C Celsius CAMP Citizen Assisted Monitoring Program cBOD 5 day Carbonaceous Biochemical Oxygen Demand Cd Cadmium CDS Continuous Deflective Separation cf Cubic foot cfs Cubic foot per second cfu Colony forming unit chl-a Chlorophyll-a Cl Chloride cm Centimeter COD Chemical Oxygen Demand Cond Conductivity Cu Copper CV Coefficient of Variance CWP Center for Watershed Protection DO Dissolved Oxygen E. coli Escherichia coli ERA Environmental Resource Associates EWM Eurasian watermilfoil F Fahrenheit F. coli Fecal Coliform Fe Iron FIN Fishing in the Neighborhood Program ft Foot GIS Geographical Information System GPS Global Positioning System Hard Hardness, Total as CaCO3 HPLC High Pressure Liquid Chromatography IBI Index of Biological Integrity

2015 Water Resources Report – Minneapolis Park & Recreation Board Page i ID Insufficient Data in/hr Inches per hour IRI Instrumental Research, Inc. IWMI Interagency Water Monitoring Initiative kg Kilogram L Liter LAURI Lake Aesthetic and User Recreation Index m Meter MAX Maximum MCES Metropolitan Council Environmental Services MCWD Minnehaha Creek Watershed District MDL Minimum Detection Limit MDNR Minnesota Department of Natural Resources mg Milligram MIN Minimum mL Milliliter Mn Manganese MnDOT Minnesota Department of Transportation MPCA Minnesota Pollution Control Agency Mpls Minneapolis MPN Most probable number MPRB Minneapolis Park and Recreation Board MPW Minneapolis Public Works msl Mean sea level MRL Minimum Reporting Limit N/A Not Applicable n/c Not Collected NA No Data Available NB No Swimming Beach NCHF North Central Hardwood Forests ND Not Detected NDC National Data Center NH3 Ammonia, Un-ionized as N Ni Nickel NO3/NO2 Nitrate+Nitrite NOAA National Oceanic and Atmospheric Administration NOx Nitrite+Nitrate, Total as N NPDES National Pollutant Discharge Elimination Systems NS Not Sampled NTU Nephelometric Turbidity Unit NURP Nationwide Urban Runoff Program NWS National Weather Service OHW Ordinary High Water Level OTP Ortho Phosphorus P Phosphorus

2015 Water Resources Report – Minneapolis Park & Recreation Board Page ii Pb Lead PE Performance Evaluation PFC Perflorinated Chemical PFOA Perflurorooctanoic Acid PFOS Perfluorooctane Sulfonate QA Quality Assurance QAPP Quality Assurance Project Plan QC Quality Control RL Reporting Limit RPD Relative Percent Difference s Second Si Reactive Silica Sp. Cond. Specific Conductivity SRP Soluble Reactive Phosphorus STDEV Standard Deviation TCMA Twin Cities Metropolitan Area TDP Total Dissolved Phosphorus TDS Total Dissolved Solids TKN Total Kjeldahl Nitrogen TMDL Total Maximum Daily Load TN Total Nitrogen TOC Total Organic Carbon TP Total Phosphorus TRPD Three Rivers Park District TSI Trophic State Index TSS Total Suspended Solids US EPA US Environmental Protection Agency USGS US Geological Survey VSS Volatile Suspended Solids WHEP Wetland Health Evaluation Program WOMP Watershed Outlet Monitoring Program WPA Works Progress Administration Zn Zinc

2015 Water Resources Report – Minneapolis Park & Recreation Board Page iii EXECUTIVE SUMMARY

As part of its stewardship of the lakes and other water bodies within the City of Minneapolis, the Minneapolis Park and Recreation Board (MPRB) monitors lakes, streams, and stormwater flows for contaminants and other water quality indicators. This report presents the results for the 2015 monitoring season. The report is primarily based on data collected by the MPRB Environmental Management Section.

In 2015, MPRB water resources scientists monitored 11 of the city’s most heavily used lakes: Calhoun, Cedar, Diamond, Harriet, Hiawatha, Isles, Loring, Nokomis, Powderhorn, Spring and Wirth Lakes. Historical data from 1991-2015 are used to calculate trophic state index (TSI) trends and estimate the trophic status for each lake. Diamond Lake was not included in this analysis since TSI scores are only appropriate for deeper lake systems and there are no water clarity measurements available in this lake. Based on the trophic state report for 2015 the following observations are made:

Lakes with increasing water Lakes with Lakes with decreasing water quality indicators stable trend quality indicators

Lake Calhoun Cedar Lake Lake Harriet Lake Nokomis Lake Hiawatha Wirth Lake Lake of the Isles Loring Pond Powderhorn Lake Spring Lake

Water Quality Highlights

The natural swimming pool at Webber Park, the first of its kind in North America, opened in 2015. Since the water quality in the pool depends on the ecological conditions in the system, MPRB Environmental Management and Maintenance staff monitors the physical, chemical and biological parameters. A total of 88% of bacteria (E. coli, Enterococci, and Pseudomonas aeruginosa) samples met standards from the German FLL, with most of the exceedances occurring in late-July and early- August.

The water quality in Lakes Calhoun and Harriet remain above average for lakes in urban settings. Indicators show better water quality in 2015 than the early 1990s and have remained stable for multiple years. Continued monitoring is assisting in developing the next generation plans for these lakes.

Wirth Lake continued its increasing water quality trend in 2015. Wirth Lake currently meets the Minnesota Pollution Control Agency (MPCA) guidelines for phosphorus, chlorophyll-a, and Secchi depth and has for most years since 2000. Wirth Lake was removed from the 303(d) list in 2014.

2015 Water Resources Report – Minneapolis Park & Recreation Board Page iv Powderhorn Lake received its twelfth barley straw treatment in 2015; however, a blue green algal bloom in the summer impacted the aesthetics and clarity of the lake.

The TSI value for Cedar Lake has remained fairly stable in recent years and indicated poorer water quality compared to the late 1990s. However, the values are still better than pre-restoration years in the early 1990s.

MCWD completed a biomanipulation project on Lake Nokomis in 2013, which aimed to reduce sediment disturbance by burrowing fish. While early results show a decline in burrowing fish populations and an above normal walleye population, the aquatic plant community is not responding quickly, as much of the littoral zone remains free of aquatic plants. It may take years to see potential benefits to biomanipulation. The TSI score in 2015 indicated a continued trend towards improved water quality. MPRB will continue to monitor long term effects of this approach.

The water quality in Lake Hiawatha is controlled by the large inflow from Minnehaha Creek, with drought years leading to lower water quality. Precipitation was slightly above average and lake levels for Hiawatha were slightly below average in 2015. The TSI score for Hiawatha was near average for the lake in 2015.

The floating biohavens in Spring Lake entered its fourth full year of establishment in 2015. The biohavens are in poor condition, are infested with invasive purple loosestrife, and three islands have become detached from their mooring. There continued to be high phosphorus and chlorophyll-a levels in Spring Lake in 2015.

In 2015, MPRB continued a project to remove hybrid and narrow-leaf cattail from Loring Pond and replant the shoreline with native vegetation. Following a successful 2014 below water cutting, a second cutting was necessary and this work was done by the contractor in August 2015 using brush saws, loppers and hand pruners either from a boat or from the shore. Herbicide treatments were applied to the floating mats and to cattails that were growing in saturated soils in early September 2015. Work in the North Bay included below water cutting and herbicide treatment of the floating mat during the growing season. A significant amount of native emergent plants that were installed as part of the 1999 shoreline planting project were found to be thriving once the cattails were removed. Most notably, large patches of sweet flag on the north end of the south pond remain intact.

The MPRB monitored 12 public beaches for Escherichia coli (E. coli, as recommended by the US Environmental Protection Agency). These bacteria are used as proxy indicators of pathogens in water. Most beaches had low season-long geometric means except Lake Hiawatha, which was the only beach to close due to exceeding the 30-day geometric mean standard of 126 MPN/100 mL during 2015. The MPCA single sample limit of 1,260 E. coli per 100 mL of water was exceeded three times at Hiawatha and once at Calhoun Thomas Beach during the 2015 beach season.

Eurasian water milfoil harvesting was carried out on Calhoun, Cedar, Harriet, Nokomis, Lake of the Isles, and Wirth Lakes in 2015 to allow for improved recreational access. SCUBA divers were contracted to hand-harvest aquatic plants at Lake Nokomis and Wirth Lake in the beach areas.

MPRB, the Minnehaha Creek Watershed District, and the Friends of Lake Nokomis worked in partnership on early detection monitoring for invasive zebra mussels. Water quality staff only found zebra mussels on a sampling plate in Lake Hiawatha in 2015. The invasive mussel has been found in the lake since 2013 and was expected to arrive in Lake Hiawatha within a few years after their discovery in Lake Minnetonka, due to its direct connection with Minnehaha Creek. No zebra mussels were found in the other Minneapolis lakes in 2015.

2015 Water Resources Report – Minneapolis Park & Recreation Board Page v

In 2015, Minneapolis was generally dry and warm for the first half of the year, and wet and warm the second half. The annual recorded precipitation total for 2015 was 36.14 inches, 0.46 inches above normal. The annual mean temperature was 48.3° F, 2.2° F above normal.

The MPRB monitors storm sewers within Minneapolis to comply with the federal National Pollutant Discharge Elimination System (NPDES) permit. The purpose of this monitoring is to characterize the impacts of stormwater discharges to receiving waters and review the effectiveness of treatment best management practices (BMPs). The results of the 2015 data were typical for stormwater as compared to reports from other cities. The MPRB monitored best management practices (BMPs) devices. BMP’s include procedures and structures designed to help reduce pollutants in stormwater runoff. The City and the MPRB carry out BMP monitoring as part of the effort to determine and improve system/BMP effectiveness through adaptive management. In 2015, baseline monitoring was continued with multiple BMP projects. These included: 1) A test and control of a St. Anthony Falls Laboratory (SAFL) baffle installed in a catch basin sump in non-standard orientation. 2) Iron Enhanced Sand Filters (IESF) at both a street and alley runoff site. 3) A flood relief vault and downstream pipe. 4) Webber Stormwater Pond, treating water and stormwater discharged from a Natural Swimming Pool and surrounding area. 5) Lyndale Dog Park E. coli bacteria sampling.

Monitoring partners for 2015 included: The Friends of Lake Nokomis, Minneapolis Public Works, the Minnehaha Creek Watershed District, and Barr Engineering.

2015 Water Resources Report – Minneapolis Park & Recreation Board Page vi 1. MONITORING PROGRAM OVERVIEW: 1991-2015

LAKE MONITORING

Background The Environmental Management Section of the Minneapolis Park and Recreation Board (MPRB) implemented a lake water quality monitoring program in 1991 as part of a diagnostic study for the Chain of Lakes Clean Water Partnership. The Chain of Lakes includes Brownie, Cedar, Isles, Calhoun, and Harriet. The monitoring program was expanded in 1992 to include Hiawatha, Nokomis, Diamond, Powderhorn, Loring, and Wirth Lakes. Monitoring at Spring Lake was added on a limited basis in 1993 and Grass Lakes was added in 2002. Currently, only ice conditions are monitored at Birch and Ryan Lakes. Ryan Lake is occasionally monitored by the Met Council’s CAMP program. Figure 1-1 shows the location of waterbodies in Minneapolis. For purposes of this overview, these 14 lakes will be collectively referred to as the Minneapolis lakes.

The objectives of the MPRB lake monitoring program are to: 1) Protect public health. 2) Establish a database for tracking water quality trends. 3) Quantify and interpret both immediate and long-term changes in water quality. 4) Provide water quality information to develop responsible water quality goals. 5) Provide a basis for water quality improvement projects. 6) Evaluate the effectiveness of implemented best management practices such as ponds and grit chambers.

The intent of this overview is to provide a description of the MPRB lakes monitoring program schedule and methods.

The 14 Minneapolis lakes and their watersheds are located within the cities of Minneapolis, St. Louis Park, Richfield, Golden Valley, Robbinsdale, Brooklyn Center, and Edina. Residential housing is the predominant land use within all of the watersheds although industrial and commercial land uses are significant in several areas. The Loring Pond watershed is predominantly parkland. All of the Minneapolis lakes’ watersheds are considered fully developed and little change in land use is projected.

The geology of the lakes and watersheds consist of Paleozoic bedrock that has been altered by fluvial processes and covered with glacial till. Area bedrock is generally concealed under 200–400 feet of unconsolidated deposits. The bedrock surface is composed of plateaus of limestone and dolomite penetrated by a system of dendritic preglacial river valleys. These river valleys were filled by a combination of fluvial sediment and late Wisconsin glacial drift. Each subsequent glacial advance stripped the landscape of overburden and filled the preglacial and interglacial valleys with drift. The last glacial episode resulted in the formation of most of the lakes in Minneapolis.

2015 Water Resources Report – Minneapolis Park & Recreation Board Page 1-1

Figure 1-1. Location of waterbodies in Minneapolis.

2015 Water Resources Report – Minneapolis Park & Recreation Board Page 1-2 The glacial ice sheet deposited large ice blocks at its margin as it retreated. Ice blocks that were deposited in a north-south tending pre-glacial (or interglacial) valley led to the formation of the Chain of Lakes. Lake Nokomis, Lake Hiawatha, and Powderhorn Lake formed as a result of a similar series of events in another preglacial valley (Zumberge, 1952; Balaban, 1989).

Nearly all of the Minneapolis lakes were physically altered by dredging in the early 1900s (Pulscher, 1997). The Minneapolis lakes currently represent a wide range of morphometric characteristics (see Table 1-1) including deep dimictic lakes (Calhoun, Cedar, Harriet, and Wirth), polymictic lakes (Hiawatha and Nokomis), protected meromictic lakes (Brownie and Spring), shallow lakes (Isles, Loring, and Powderhorn), and shallow wetland systems (Diamond and Grass).

Table 1-1. Minneapolis lakes morphometric data.

Surface Mean Watershed: Residence Max % Volume Watershed Lake Area Depth 3 Lake Area Time Depth (m) Littoral* (m ) Area (acres) (acres) (m) (ratio) (years) Brownie 18 6.8 15.2 67% 4.98x105 369 20.5 2.0 Calhoun 421 10.6 27.4 31% 1.80x107 2,992 7.1 4.2 Cedar 170 6.1 15.5 37% 4.26x106 1,956 11.5 2.7 Diamond 41 0.9† 2.1† 100% 7.15x104 669‡ 16.3 NA Grass 27 0.6 1.5 NA NA 386 14.3 NA Harriet 353 8.7 25.0 25% 1.25x107 1,139 3.2 3.4 Hiawatha 54 4.1 7.0 26% 8.95x105 115,840 2145 0.03 Isles 103 2.7 9.4 89% 1.11x106 735 7.1 0.6 Loring 8 1.5 5.3 NA 4.88x104 24 3.0 NA Nokomis 204 4.3 10.1 51% 3.54x106 869 4.3 4.0‡ Powderhorn 11 1.2 6.1 99% 9.04x104 286 26.0 0.2‡ Ryan 18 NA 10.7 50% NA 5,510 306 NA Spring 3 3.0 8.5 NA 3.65x104 45 15.0 NA Wirth 39 4.3 7.9 61% 6.70x105 348 9.4 NA *Littoral area defined as less than 15 feet deep † Based on long term average data. ‡Recent projects have altered these statistics. NA= Information not available.

2015 Water Resources Report – Minneapolis Park & Recreation Board Page 1-3 Methods The 2015 lake monitoring schedule of physical and chemical parameters is shown in Table 1-2. Most lakes followed this schedule and were sampled once per month in February, April, and October and twice per month during the period of May through September. Spring Lake was only sampled once per month. Diamond was not sampled in winter because it was frozen to the bed.

Table 1-2. Schedule of sampled parameters for most lakes in 2015.

Parameter Winter March/April May – Sept October Alkalinity Once Once Once Once Calcium, Potassium, Magnesium Once Once Once Once Chloride Once Once Twice a Month Once Chlorophyll-a Once Once Twice a Month Once Conductivity Once Once Twice a Month Once Dissolved Oxygen Once Once Twice a Month Once Escherichia Coli Not sampled Not Sampled Once Not Sampled Hardness Once Once Once Once pH Once Once Twice a Month Once Phytoplankton Once Once Twice a Month Once Secchi Transparency Once Once Twice a Month Once Silica Once Once Once a Month Once Sulfate Once Once Once Once Temperature Once Once Twice a Month Once

TKN, NOx Once Once Once Once TP, SRP, TN Once Once Twice a Month Once Turbidity Once Once Twice a Month Once Zooplankton Not sampled Once Once a Month Once

All physical measurements and water samples for chemical analyses were obtained from a point directly over the deepest point in each lake (sampling station). The sampling stations were determined from bathymetric maps and located using handheld GPS or shoreline landmarks and an electronic depth finder.

A Hydrolab Minisonde 5 Multiprobe was used to record temperature, pH, conductivity, dissolved oxygen, and turbidity profiles. These parameters were measured at 1-meter intervals from the surface to the lake bottom. The multiprobe was calibrated according to the manufacturer’s guidelines prior to each sampling trip. Secchi disk transparency was determined with a black and white 20-cm diameter disk on the shady side of the boat.

Two composite surface water samples were collected using a stoppered 2-m long, 2-inch diameter white PVC tube and combined in a white plastic bucket. Water from this mixed sample was decanted into appropriate bottles for analysis. Chlorophyll-a samples were stored in opaque bottles for analysis. Total phosphorus, soluble reactive phosphorus, total nitrogen, and chlorophyll-a concentrations were determined from the surface composite sample for all sampling trips. Phytoplankton samples were collected during each sampling trip from April through October for all lakes (Table 1-2). Phytoplankton were collected from the 0-2 m surface composite sample and stored in an opaque plastic container with a 25% glutaraldehyde preservative solution. Vertical zooplankton

2015 Water Resources Report – Minneapolis Park & Recreation Board Page 1-4 tow samples were taken at the sampling station for each lake once per month during the growing season (except at Brownie Lake, Diamond Lake, Grass Lake and Spring Lake). Zooplankton were collected using a 80-µm mesh Wisconsin vertical tow net with an 11.7 cm diameter opening retrieved at a rate of 1 m s-1 from approximately 1 m off the bottom through the full water column to the surface. The 80-µm mesh Wisconsin bucket was rinsed with distilled water or ethanol from the outside. The sample was preserved 90% denatured histological ethanol to a mix of approximately 50% sample 50% ethanol.

Subsurface samples were collected with a 2-liter Wildco Kemmerer water sampler. Total phosphorus and soluble reactive phosphorus concentrations were determined every sampling trip at predetermined depths in each lake (Table 1-3). In addition, deep subsurface chloride samples were also taken at most lakes. Each lake sample collection regime was determined based upon maximum depth, stratification characteristics and the results of previous studies.

Table 1-3. Sampling depth profiles for the 2015 MPRB lakes monitoring program.

Lake Sampling Depths in meters Lake Calhoun 0-2 composite 6 12 18 22 Cedar Lake 0-2 composite 5 10 14 Diamond Lake Grab (surface) Lake Harriet 0-2 composite 6 12 15 20 Lake Hiawatha 0-2 composite 4 Lake of the Isles 0-2 composite 5 8 Loring Pond 0-2 composite 4 Lake Nokomis 0-2 composite 4 6 Powderhorn Lake 0-2 composite 4 6 Spring Lake 0-2 composite 4 6 Wirth Lake 0-2 composite 4 7

Immediately following collection all samples were placed on ice in a cooler and stored at approximately 4°C. Samples were transported to the contract laboratory for analysis within 8 hours of collection. Sampling procedures, sample preservation and holding times followed procedures described in Standard Methods (2005) or US Environmental Protection Agency (US EPA, 1979 (revised 1983)). The 2015 contract laboratory for chemical analyses was Instrumental Research, Inc. (IRI). PhycoTech, Inc. analyzed all phytoplankton and zooplankton samples. The methods and reporting limits for parameters are listed in Table 1-4.

2015 Water Resources Report – Minneapolis Park & Recreation Board Page 1-5 Table 1-4. Methods and reporting limits used for parameter analysis in the 2015 Minneapolis lakes monitoring program.

Parameter Method Reporting Limit Alkalinity STANDARD METHODS 2320 B 2.00 mg/L Calcium EPA 200.7 1.00 mg/L Chloride STANDARD METHODS 4500-Cl- B 2.00 mg/L Acetone extraction/spectrophotometric determination Chlorophyll-a 0.500 µg/L (pheophytin corrected) SM 10200 H Conductivity Hydrolab Minisonde 5a Multiprobe (field) 0.1 µS/cm Dissolved Oxygen Hydrolab Minisonde 5a Multiprobe (field) 0.01 mg/L Escherichia coli Colilert Quanti-Tray, IRI 1 mpn Hardness STANDARD METHODS 2340 C 2.00 mg/L Magnesium EPA 200.7 1.00 mg/L

Nitrate+Nitrite Nitrogen STANDARD METHODS 4500-NO3 E 0.030 mg/L Potassium EPA 200.7 1.00 mg/L Silica STANDARD METHODS 4500-Si O2-97 0.500 mg/L Soluble Reactive Phosphorus STANDARD METHODS 4500-P E. 0.003 mg/L Sulfate ASTM D516-90 15 mg/L Temperature Hydrolab Minisonde 5a Multiprobe (field) 0.01 °C Total Dissolved Phosphorus STANDARD METHODS 4500-P E. 10 µg/L Total Kjeldahl Nitrogen ASTM D3590 A-02 0.500 mg/L STANDARD METHODS 4500 N C Alkaline persulfate Total Nitrogen 0.500 mg/L oxidation/automated cadmium reduction method. Total Phosphorus STANDARD METHODS 4500-P E. 0.010 mg/L Turbidity Hydrolab Minisonde 5a Multiprobe (field) 1 ntu Transparency Secchi disk depth measurement 0.01 m

More information and results for the physical and chemical parameters can be found in individual lake sections and Appendix B.

2015 Water Resources Report – Minneapolis Park & Recreation Board Page 1-6 WELLS

Background Groundwater levels are monitored by the MPRB staff at seven piezometric wells. Piezometric wells are drilled to specific depths in order to monitor hydraulic head, the groundwater pressure above a known datum. Irrigation wells use groundwater for golf course turf and greens area maintenance. Augmentation wells are used to maintain water levels at lakes and ponds and, if permitted, are occasionally used for winter ice rinks. Figure 1-2 is a map of the piezometric, irrigation, and augmentation well locations in Minneapolis.

The Minnesota Department of Natural Resources (MDNR) issues the permits and determines pumping limits for irrigation and augmentation wells. The MPRB is not allowed to exceed these limits. Annual fees and reports are sent to the MDNR. The MPRB staff records groundwater levels from piezometric wells throughout Minneapolis.

Methods Piezometric well readings are taken with a Herron Instrument Water Level Meter. This water tape is read at the top of the well casing to +/- 0.01 feet and its accuracy complies with US GGG-T-106E EEC Class III protocols. Piezometric wells A, B, and C are monitored once a month January, February, March, and December and twice a month April through November. Wells D, E, F, and G are monitored quarterly.

Results & Discussion The piezometric well readings are taken throughout the year and data is archived in a MSExcel spreadsheet.

Results from the 2015 lake augmentation well readings and annual usage can be found in the Powderhorn Lake and Loring Pond sections. All of the irrigation and augmentation wells used were below their MDNR allotted groundwater pumping volumes.

2015 Water Resources Report – Minneapolis Park & Recreation Board Page 1-7

Figure 1-2. Map of piezometric and irrigation/augmentation well locations monitored by MPRB Environmental Management.

2015 Water Resources Report – Minneapolis Park & Recreation Board Page 1-8 WATER QUALITY TRENDS (TSI)

Scientists have analyzed water quality parameters in Minneapolis lakes sporadically since 1927 and consistent bi-weekly monitoring began in 1991. In 2015, the MPRB monitored 11 city lakes according to the current schedule and protocols (Table 1-2). The data collected was used to determine nutrient related water quality (trophic status) and general usability.

Trophic status is used to estimate water quality and is based on Carlson’s Trophic State Index (TSI; Carlson, 1977). Trophic state is calculated using three nutrient related water quality parameters collected from surface water: water transparency (Secchi depth), chlorophyll-a (chl-a), and total phosphorus (TP).

Water transparency is measured using a 20-cm black and white Secchi disk. The Secchi disk is lowered into the water until it cannot be seen. Then it is lowered a short distance further and raised until it is seen again. The average of these two numbers represents the Secchi depth. The Secchi depth is dependant on algal biomass or other factors that may limit light penetration (e.g. suspended solids, dissolved organic material).

Chlorophyll-a is a pigment algae use to capture sunlight and is a measure of how much algal biomass is in the lake.

Phosphorus is often the limiting nutrient in most freshwater lakes and therefore controls the growth of algae. By measuring TP in lake water it is possible to estimate algal growth and the potential for algal blooms (high algal growth).

Individual Secchi, chl-a, and TP TSI scores are calculated for the growing season (May-September) for each lake. The annual lake TSI score is the average of the individual (Secchi, chl-a and TP) TSI scores. It should be noted that some annual lake TSI scores are an average of only two parameters (chl-a TSI and TP TSI) if a Secchi is not or cannot be taken on a particular lake. The individual TSI formulas are below.

Secchi TSI= (60-14.41)*ln (Average growing season Secchi in meters)

Chl-a TSI= 9.81*ln (Average growing season chl-a in µg/L)

TP TSI= 14.42*ln (Average growing season TP in mg/L*1000) + 4.15

Annual TSI= (Secchi TSI + chl-a TSI + TP TSI)/3

TSI scoring is based on a 0-100 scale, although theoretically the scale has no upper or lower bounds, with higher numbers relating to higher trophic status and lower water quality. Three TSI scores are possible using the parameters described above and can be reported separately or as an average. The TSI score based on chl-a is thought to be the best measure of trophic state because it is the most accurate at predicting algal biomass (Carlson, 1977). TSI scores reported by the MPRB are an average of the three parameters.

It is important to consider soil type and land use in the surrounding watershed when using the TSI to determine lake water quality. The State of Minnesota has seven ecoregions determined by land use, soil type, and natural vegetation. Minneapolis lies within the North Central Hardwood Forests (NCHF) ecoregion, an area with fertile soils and agriculture as a dominant land use in rural areas.

2015 Water Resources Report – Minneapolis Park & Recreation Board Page 1-9 Lakes in this ecoregion generally have higher concentrations of nutrients and 90% of the TSI scores are between 41 and 77. In the Twin Cities metro area it is recommended that a TSI score of 59 or lower be maintained in lakes used for swimming. This recommendation is based upon the aesthetic appeal of the water body.

One of the methods used to classify lakes involves using categories based on the TSI score. Lakes generally fall into one of four categories based on trophic status that include:

Oligotrophic (TSI < 30) lakes are characterized by low nutrients, oxygen throughout the water column and clear water. Salmonid fisheries may dominate

Mesotrophic (40 > TSI < 50) lakes generally are moderately clear and have an increased probability of experiencing hypolimnetic anoxia during the summer months

Eutrophic (50 > TSI < 70) lakes are considered fertile and characterized by high algal biomass and may have macrophyte problems in some systems. Hypolimnetic anoxia occurs in stratified lakes and only warm water fisheries can be sustained.

Hypereutrophic (TSI > 70) lakes are characterized by high nutrient concentrations, leading to frequent severe algal blooms and low macrophyte densities due to light limitation by algae.

Most lakes in the NCHF ecoregion fall into the eutrophic category and the lowest trophic status lakes typically fall into the mesotrophic category. All the sampled lakes in Minneapolis are either eutrophic or mesotrophic. Detailed information on TSI scores and nutrient related water quality parameters can be found in the individual lake sections and Appendix A.

Changes in lake water quality can be tracked by analyzing long-term trends in TSI scores. The MPRB uses TSI scores to assess changes in water quality and evaluate the effectiveness of restoration and management activities on the trophic state of the lakes. Linear regression analysis is a common method used for determining trends in average TSI over time. A graph was made of average annual TSI scores for each lake (found in each individual lake’s section). A trend line was fit through the data points. The linear regression line is defined as y = mX + b, where m is the slope of the line. The slope indicates the general trend of the data. The p-value indicates the probability of the observed trend even if there isn’t one. The use of a p-value of <0.05, meaning there is a 5% chance there isn’t a trend even if one is observed, is frequently used to determine if a trend is statistically significant. The R2 value indicates how well the trend fits the data with 1.00 being a perfect fit. Based upon these results it is possible to describe the direction of the trend (a negative or positive slope) and the degree of confidence one can place upon the trend. Better water quality and decreasing productivity in surface water is generally indicated by a decreasing TSI score and negative slope of the regression equation (as shown in the TSI figures in each individual lake’s section). Conversely, a positive slope and increasing TSI scores generally indicates increasing productivity and a decrease in water clarity.

2015 Water Resources Report – Minneapolis Park & Recreation Board Page 1-10 BOX AND WHISKER PLOTS

Additional analysis of the three TSI parameters can include using box and whisker plots. The box and whisker plots for each lake are another way to determine trends and are valuable for assessing variability over the years. Box and whisker plots can be used to look at short-term (seasonal) and long-term trends at the same time. Box plots for the three trophic state parameters (transparency, surface chlorophyll-a levels and surface total phosphorus levels) were created for each lake and presented in individual lake sections.

For each plot the box represents the middle 50 percent of the data from the 25th percentile to the 75th percentile. The “whiskers” (the vertical lines extending off of the boxes) represent the data from the 25th and 75th percentiles to the 5th and 95th percentiles, respectively. Any data falling above the 95th percentile or below the 5th percentile are marked as outliers. The horizontal line that cuts across the box represents the median value. In this report, all outliers in the box and whisker plots are represented by a circle.

Generally more compact box plots with short “whiskers” and few outliers indicate low yearly variability for the lakes. Long-term trends can be seen by the box plots trending in an up or down direction.

Outlier

95th Percentile

75th Percentile

Median

25th Percentile

5th Percentile

2015 Water Resources Report – Minneapolis Park & Recreation Board Page 1-11 LAKE AESTHETIC AND USER RECREATION INDEX (LAURI)

Many lake monitoring programs use Carlson’s TSI to track the environmental health of a lake. The TSI index is not intuitive or readily understandable to the general public. Additionally, TSI does not measure recreational access issues.

In 2004, the MPRB worked with Barr Engineering Company with funding from Minneapolis Public Works to develop a new index. The original Lake Aesthetic and User Recreation Index (LAURI) was the result of this development. It was designed to give recreational users a source of information about conditions affecting their use of city lakes. The goal was to have an easily understandable recreational indicator. The two major constraints in developing the indices were that they were to be collected by existing water quality staff and within the existing budget.

In 2009, the LAURI was further refined to give a more accurate, and science based indicator for the public. The revised LAURI has five indices:

 Public Health (E. coli measured at public swimming beaches)  Water Quality (water clarity/Secchi depth)  Habitat Quality (aquatic plant and fish diversity)  Recreational Access (availability and ease of public access)  Aesthetic Considerations (color and odor of water, garbage and debris)

Data for the LAURI analysis is collected during regular lake monitoring activities and once a month during beach monitoring trips during the growing season from May to September.

The LAURI has proven to be useful to users of the Minneapolis park system. Someone interested in walking or biking around a lake may use only the aesthetic score. A swimmer may compare lakes based on the public health, aesthetic, and water quality scores. A sailor or kayak user may be primarily concerned with the recreational access score.

Public Health Index To determine whether a lake meets guidelines for full-body recreational contact for people the existing beach monitoring program data were used. E. coli, the indicator recommended by the Environmental Protection Agency (EPA), was measured at every public beach in the park system. Beaches exist on Calhoun, Cedar, Harriet, Hiawatha, Nokomis, and Wirth Lakes. The scoring used the season long geometric mean from the beach monitoring program for each lake (Table 1-5). At lakes with more than one beach, beaches were averaged together. This metric was chosen because US EPA and Minnesota guidelines state that beaches should not exceed a geometric mean of 126 organisms per 100 mL during a 30-day time period. Lower numbers of organisms indicate less risk of illnesses for lake users.

2015 Water Resources Report – Minneapolis Park & Recreation Board Page 1-12 Table 1-5. Scoring for the public health portion of LAURI.

E. coli bacteria, (MPN/100mL) * Score <2 (Not Detected) 10 2 - 10 9 11 - 20 8 21 - 35 7 36 - 50 6 51 - 65 5 66 - 80 4 81 - 100 3 101 - 125 2 >126 1 * The value used is the running geometric mean for the year, averaged for all the beaches on a lake.

Water Quality Index Water clarity is easy to measure and understand. This simple measure is a good integrator of various parameters affecting the eutrophication status of a lake. The lakes are separated into deep lakes and shallow lakes using criteria developed by the Minnesota Pollution Control Agency (MPCA). A shallow lake is defined as 80% littoral (< 15 feet deep). Calhoun, Cedar, Harriet, and Wirth were considered deep lakes. Loring, Isles, Hiawatha, Nokomis, and Powderhorn are considered shallow lakes. Higher numbers indicate clearer water. LAURI scoring uses the average Secchi transparency reading from all the data collected during the growing season (May-September; Table 1-6).

Table 1-6. Scoring for the water quality portion of LAURI.

Secchi Depth (m) Deep Lake Score Shallow Lake Score 0 - 0.5 1 2 0.6 - 1 2 4 1.1 - 1.5 3 6 1.6 - 2.0 4 8 2.1 - 2.5 5 10 2.6 - 3.0 6 3.1 - 3.5 7 3.6 - 4.0 8 4.1 - 4.5 9 > 4.6 10

2015 Water Resources Report – Minneapolis Park & Recreation Board Page 1-13 Habitat Quality Index LAURI assessments of habitat quality are determined by the most recent survey information. Macrophyte surveys were conducted by MPRB staff and scoring is based on presence of aquatic plants (macrophytes), density of plants, and amount of coverage (Table 1-7). The more aquatic plants are observed, the higher the habitat quality index was scored. Fish surveys were conducted by MNDNR and points are awarded for diverse fish populations. The score from the aquatic plant and fish surveys are averaged for the LAURI.

Table 1-7. Scoring for the habitat portion of LAURI.

Macrophyte Coverage # Fish Score Density Score Score Score species >15 ft. species 0 0 Low 0 0-25 2 ≤6 2 1-2 3 Low-med 3 25-50 4 7-8 4 2-4 6 Medium 6 50-75 7 9-11 6 5-6 8 Med-high 8 75-100 10 12-14 8 > 6 10 High 10 ≥15 10

Recreational Access Index The lakes are also scored for the quantity of recreational access to the water. The recreational score considers the number of fishing docks, beaches, boat launches, intra lake connections, canoe racks and rentals, picnic areas, and concessions at a lake (Table 1-8). While aquatic plants are a necessary part of a healthy lake ecosystem, they can also interfere with recreational uses of the lake; therefore, lakes also receive points for invasive plant growth management.

Table 1-8. Scoring for the recreational access portion of LAURI.

Recreational Op # Total # Ops + Aq Plnt Mgmt Score Fishing Dock 0 1 Beach 1 2 Boat Landing 2 3 Boat rental 3 4 Boat storage 4 5 Picnic area 5 6 Concessions 6 7 Aquatic Mgmt = + 4 7 - 8 8 yes Aquatic Mgmt = + 0 8 - 9 9 no TOTAL > 10 10

2015 Water Resources Report – Minneapolis Park & Recreation Board Page 1-14 Aesthetic Considerations Index The lakes are scored for water color, odor, and debris based on an assessment done from shore, dock, or boat (Table 1-9). Lower numbers indicate worse aesthetics. The scores are averaged over the season. Aesthetics can be difficult to evaluate as they are strongly qualitative and dependent on individual experience.

Table 1-9. Scoring for the aesthetic portion of LAURI.

Color Score Odor Score Debris Score Clear 10 None/Natural 10 None 10 lt. Brown or green 8 Musty - faint 8 Natural 9 Bright Green 5 Musty - strong 6 Foam 8 Sewage/fishy/ garbage - Milky White 4 5 Piles of milfoil (>3) 7 faint Brown/Reddish/ Sewage/fishy/ garbage - 2 2 Trash: fixed (>3) 4 Purple strong Gray/Black 0 Anaerobic/septic 0 Trash: floating (>3) 3 Many dead fish (>5) 2 Green scum 2 Oil film 1 Sewage Solids 0

WINTER ICE COVER

An interesting climatological statistic to track over time is the date that a lake freezes in the fall and the date it thaws in the spring. Ice phenology affects migration and breeding patterns of birds, food supply of fish and animals, and water chemistry. Length of ice cover in our region is affected by local weather patterns as well as changes in regional and global cycles. Magnuson, et al (2001) found that northern hemisphere temperate climate ice records reflected changes in the strength of a low pressure zone that builds over the Aleutian Islands (the Aleutian Low) and El Nino cycles (cycles of warming the surface waters of the tropical Pacific Ocean). Ice-out and -on dates are given in the individual lake sections and a comparison among lakes can be found in Section 18 in Tables 18-7 and 18-8. Ice-off and ice-on dates are reported to the MPCA and MDNR to include in their statewide long-term ice record.

However, some caution must be used when interpreting the historical data. Over the years many different people have been responsible for writing down the dates and ice dates can be somewhat subjective with people using different observation techniques. Since 2000, the MPRB has been using the definition of ice-on as occurring when the lake is 100% covered with ice, preferably in the afternoon (when ice may break up on a sunny day). Ice-off occurs when the lake is essentially ice free (<10% covered with ice).

2015 Water Resources Report – Minneapolis Park & Recreation Board Page 1-15 AQUATIC PLANTS

Aquatic plants (macrophytes) form the foundation of a healthy lake ecosystem. They provide important habitat for insect larvae, snails, and other invertebrates which are food sources for fish, frogs, turtles, and birds. Aquatic plants also provide shelter for fish and food for waterfowl. Therefore, the health of a lake depends upon having a healthy plant community. MPRB assesses macrophyte communities in the Minneapolis lakes on a rotating basis. No macrophyte surveys were conducted in 2015; however, all lakes were visually assessed for curly-leaf pondweed during June.

Lakes with macrophytes are usually clearer than lakes without macrophytes. Plant roots stabilize sediments and shorelines and prevent the suspension of sediments (from wind or fish) that would otherwise result in turbid or murky waters. Aquatic plant growth produces oxygen and uses nutrients from the water column and from the sediments which would otherwise be used by algae. Macrophytes add an enormous amount of surface area to lakes providing habitat for microscopic plants and animals to grow and utilize nutrients otherwise available to planktonic algae. Large zooplankton use aquatic plants as a refuge against fish. Lakes with a vegetation-dominated clear state typically have more diverse fish communities and larger numbers and diversity of waterfowl.

Eurasian Watermilfoil Control Program Overgrowth of Eurasian watermilfoil (Myriophyllum spicatum) is a recreational access problem in several Minneapolis lakes. From a recreational perspective, milfoil is problematic in that it forms dense floating mats that interfere with boating and swimming. From an ecological standpoint, milfoil can provide vertical structure and habitat for fish; however, it can also be too dense to provide good fish habitat. Eurasian watermilfoil also out-competes native species and may reduce the available habitat for other species.

Currently, no method has been proven to rid lakes of milfoil without significant non-target effects, but several management methods exist to treat the symptoms of infestation. The MPRB primarily uses mechanical harvesting to control the growth of milfoil in city lakes. Harvesting milfoil is analogous to mowing a lawn. Only the top two meters of the milfoil plants are removed but this temporarily allows for problem-free boating and swimming. Harvesting was completed on Calhoun, Cedar, Harriet, and Lake of the Isles. SCUBA divers hand pulled milfoil out of heavily used recreational areas in Lake Nokomis and Wirth Lake. For acreage see individual lake sections. MPRB Staff removed 211 flatbed truck loads of milfoil in 2015 which is comparable to 1158 cubic yards of aquatic plant material.

PHYTOPLANKTON AND ZOOPLANKTON MONITORING

Background Biological parameters are routinely measured as part of a lake’s assessment. Phytoplankton (algae) and zooplankton are two of the common biological parameters collected because they are essential to the aquatic food web and influence other aspects of the lake including color and clarity of the water and fish production.

Phytoplankton are microscopic plants that are an integral part of the lake community. Phytoplankton use nutrients in the water and sunlight to grow and are the base of the aquatic food web. Chlorophyll- a is the primary photosynthetic pigment contained in algae. Chlorophyll-a concentration can be easily measured in a water sample and is a common way to estimate the phytoplankton biomass in the water (Paerl and Sandgren, 1998).

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Zooplankton are tiny animals that feed on phytoplankton and other zooplankton. They are vital to the lake community and form the second level in the food web. Rotifers and arthropods are the two most commonly found zooplankton in Minneapolis lakes. Rotifers are smaller in size but are of great importance in the aquatic food web because of their abundance, distribution, and wide range of feeding habits. Copepods and cladocerans are larger arthropods and members of the class Crustacea. Copepods are the most diverse group of crustaceans. A cladoceran genus, Daphnia, is known as the common “water flea” and is a very well-known zooplankton.

Methods

Phytoplankton Phytoplankton samples were collected twice a month from most of the monitored lakes (Calhoun, Cedar, Harriet, Hiawatha, Isles, Loring, Nokomis, Powderhorn, and Wirth) except for February, April, and October which were sampled once per month. Samples were collected once a month at Brownie, Diamond, Grass, and Spring Lakes. Surface water composite samples were collected for phytoplankton using a 2-m long, stoppered 2-inch diameter PVC tube. Two such samples were mixed in a clean white plastic bucket that had also been scrubbed and rinsed with lake water. Water from this mixed sample was decanted for analysis into amber bottles, preserved with 25% glutaraldehyde (a preservative) back at the lab and sent to PhycoTech Incorporated (St. Joseph, MI) laboratory for analysis. Analysis was completed using the phytoplankton rapid assessment count developed by Edward Swain and Carolyn Dindorf of the MPCA. This method involves a sub-sample being placed in a counting chamber and analyzed using an inverted microscope. The algal division, taxa, genus, and species are identified and the percent abundance by volume is estimated. Identification protocol is according to Weber (1971) and Prescott (1951). The results are presented by division (phylum) in the individual lake sections. Common phytoplankton divisions and a common description are given in Table 1-10.

Table 1-10. Phytoplankton divisions and brief descriptions.

Division Description Bacillariophyta Diatoms Chlorophyta Green algae Chrysophyta Golden-brown algae Cryptophyta Cryptomonads Cyanophyta Blue-green algae Euglenophyta Euglenoids Haptophyta Haptophytes Pyrrhophyta Dinoflagellates Xanthophyta Yellow-brown algae

Chlorophyll-a concentrations were used to estimate phytoplankton biomass in the lakes. Each lake section shows chlorophyll-a concentrations and the distribution of phytoplankton divisions throughout the sampling season.

2015 Water Resources Report – Minneapolis Park & Recreation Board Page 1-17 Zooplankton Zooplankton samples were collected monthly from most Minneapolis lakes (Table 1-2). Diamond and Grass Lakes were not sampled because of their shallow depths. Brownie and Spring Lakes were not sampled due to lack of zooplankton in most years. Samples were collected using an 80-µm plankton net with an 11.7 cm diameter opening and a Wisconsin-type bucket. The net was raised from approximately one meter above the bottom to the surface at a rate of one meter per second. The captured zooplankton were rinsed into a bottle using 90% denatured histological ethanol to a final concentration of 50% sample and 50% preservative. The distance the net was pulled through the water column (tow depth) was recorded on field sheets and on the bottle label. Zooplankton were identified at PhycoTech Inc. as completely as possible by: class, subclass, order, suborder, family, genus, species, and subspecies. Zooplankton were identified according to standard protocols and twelve taxonomic authorities (Edmondson, 1959). The zooplankton results were divided into groups for presentation as shown in Table 1-11. Results are presented in the individual lake sections.

Table 1-11. Major zooplankton groups and brief descriptions.

Major Group Description Calanoid Phylum Arthropoda. Type of copepod. Generally herbivorous. Cladoceran Phylum Arthropoda. Eats algae. Commonly called “water flea.” Cyclopoid Phylum Arthropoda. Type of copepod. Many are carnivorous. Protozoan Single celled organisms. Many are shelled amoeba. Rotifer “Wheel animals.” Eat particles up to 10 μm.

FISH STOCKING

Many of the lakes in Minneapolis are stocked with fish by the MDNR. This information is on the MDNR LakeFinder website (http://www.dnr.state.mn.us/lakefind/index.html).

Stocking Fish Sizes:  Fry - Newly hatched fish. Walleye fry are 1/3 of an inch or around 8 mm.  Fingerling - Fingerlings are one to six months old and range in size from one to twelve inches.  Yearling - Yearling fish are at least one year old and can range from three to twenty inches.  Adult - Adult fish that have reached maturity age.

FISH KILLS

Many of the summer fish kills in Minneapolis lakes are attributed to Columnaris bacteria. The naturally occurring Flexibacter columnaris bacteria cause the disease. This disease is usually associated with a stress condition such as high water temperature, low dissolved oxygen concentration, crowding, or handling. Symptoms of this disease include grayish-white lesions on parts of the head, fins, gills, or body usually surrounded by an area with a reddish tinge. On crappies the lesions are generally confined to the fins and gills and rarely extend to the body.

2015 Water Resources Report – Minneapolis Park & Recreation Board Page 1-18 Columnaris is known to only infect fish species and is not a health risk to humans. The bacteria are most prevalent in lakes when water temperatures approach 65-70 degrees F from late May to late June. Columnaris levels can increase after a major rainfall and runoff which supply additional nutrients to area lakes. Bluegill, crappie, yellow perch, and bullhead fish species are most affected by the disease. The Columnaris disease causes erosion of the fishes’ skin causing a leakage of the bodily fluids and an influx of lake water into the fishes’ body. There is little that the MDNR or the public can do to prevent this naturally occurring phenomenon.

Winter fish kills on lakes are often due to thick ice and snow cover leading to low dissolved oxygen conditions in the water below. Usually small lakes and ponds are most affected by winter fish kills. The MPRB reports all fish kills to the MDNR to aid in determining the cause.

QUALITY ASSURANCE/QUALITY CONTROL

The contract laboratory analyzed blanks and appropriate standards with each set of field samples. Equipment blanks were analyzed to detect any equipment contamination. In addition, field duplicate samples were analyzed each lake sampling trip (weekly) and blind laboratory performance standards were analyzed every month sampling occurred. Field blanks were done every sampling trip. Ideally, laboratory split samples are analyzed twice a year between a minimum of three labs.

Calibration blanks, reagent blanks, quality control samples, laboratory duplicate samples, and matrix spike/duplicate samples were analyzed at a 10% frequency by the contract laboratory. The quality control samples analyzed by the laboratory consisted of two sets:

 samples of known concentration (control standards) that served as a independent verification of the calibration standards and as a quality control check for the analytical run and  Blind samples (of unknown concentration) provided by the MPRB Environmental Operations staff.

For more details and QA/QC results for 2015, see the Quality Assurance Assessment Report in Section 28.

2015 Water Resources Report – Minneapolis Park & Recreation Board Page 1-19 2. BIRCH POND

HISTORY

Birch Pond is a 6-acre water body on the east side of Theodore Wirth Parkway in Theodore Wirth Regional Park near the Eloise Butler Wildflower Garden and Bird Sanctuary, Figure 2-1. The pond lies within the original Glenwood Park parcel. In 1910, the pond was named for the white birch trees which grew along its shores and hillsides. It has no public boat access or fishing docks. Birch Pond is protected from winds by large hills and mature trees that surround it. Aesthetics and bird watching opportunities are Birch Pond’s main recreational values.

Buckthorn (Rhamnus cathartica and Rhamnus frangula) was removed from the understory of the Birch Pond basin in 2006 as a part of vegetation restoration efforts in preparation for the centennial anniversary of the Eloise Butler Wildflower Garden and Bird Sanctuary. Buckthorn is an invasive species that threatens native woodlands.

The Minneapolis Park & Recreation Board (MPRB) currently does not include Birch Pond in its regular lake sampling program and only monitors ice-off and -on dates.

Figure 2-1. Birch Pond after 2006 buckthorn removal.

2015 Water Resources Report – Minneapolis Park & Recreation Board Page 2-1

LAKE LEVEL

Lake level records for Birch Pond were historically kept by both the City of Minneapolis and the MPRB. More recently, the MDNR has created an accurate bench mark and has set an Ordinary High Water Level (OHW) of 846.3 msl for Birch Pond. Lake levels in Birch pond have varied over time due to changes in climate and rainfall patterns as well as periodic augmentation through pumping. Birch Pond was once part of a water conveyance system which carried water from the Mississippi River to the Chain of Lakes. A remnant of the old conveyance system remains on the east side of the pond. There is currently not a surveyed lake level gauge on Birch Pond.

Figure 2-2 shows historic water level records for Birch Pond compiled by the MPRB, the City of Minneapolis and the MDNR.

Figure 2-2. Historic level records for Birch Pond compiled by MPRB, City of Minneapolis and MDNR. Fluctuations are due to climate, season, and historic pumping.

WINTER ICE COVER

Ice came off Birch Pond on March 30, 2015, which was five days earlier than average. Ice came back to the pond November 30, 2015, five days later than the average date for ice-on. See Section 18 for additional ice monitoring data.

2015 Water Resources Report – Minneapolis Park & Recreation Board Page 2-2 3. BROWNIE LAKE

HISTORY

Human activities drastically changed the shape and size of Brownie Lake over the past 150 years. Construction of a railroad embankment in 1883 caused a decrease in lake surface area of 34%, transforming the lake formerly known as Hillside Harbor. In 1916, the connection between Cedar and Brownie Lakes was completed further decreasing the surface area of the lake by another 56% by dropping the water level 3 m (~10 ft) and creating the lake that we see today (Wirth, 1945; Trembley, 2012). Figure 3-1 shows a picture of Brownie Lake.

Figure 3-1. Kayakers on Brownie Lake

Structural changes to the lake have had implications to its water chemistry. Brownie Lake is permanently stratified (also called meromictic) due to a strong density difference that exists between water near the surface and a deeper layer of water containing high levels of dissolved minerals. The sharp density difference between the surface waters and deeper water in meromictic lakes is called a chemocline. Meromictic lakes do not mix due to the stability of the chemocline and makes them difficult to compare with dimictic or polymictic lakes. Swain (1984) first theorized that the structural changes made to Brownie Lake caused its state of permanent stratification. Swain’s 1984 study of a 117-cm lake sediment core found changes in the ratios of iron to manganese (Fe:Mn) and iron to phosphorus (Fe:P) at a layer in the sediment corresponding to approximately 1925. The change in the chemistry of the sediments indicates the onset of permanently anoxic bottom-water signifying to Swain that Brownie Lake had become meromictic. In the past, stormwater inputs from Interstate 394 (old U.S. Highway 12) added pollutants to Brownie Lake and has contributed to the stability of the chemocline. Currently, Brownie Lake receives runoff from both Minneapolis and St. Louis Park.

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Swain’s lake-core analysis found further evidence of the influence that human activities had on Brownie Lake. Ragweed pollen first appeared at sediment core at depths that corresponding to 1850- 1860, an indication of European-American settlement (Swain, 1984). Later, changes in the watershed led to increases in primary productivity, algal biomass, and sediment accumulation indicating eutrophication. As water clarity decreased over time benthic diatoms were replaced by planktonic forms and the zooplankton community shifted from large bodied Daphnia to the smaller Bosmina species (Swain, 1984).

Water levels in Brownie Lake have been manipulated at various times in its history. Groundwater was first used to augment lake levels in the Chain of Lakes (Brownie, Cedar, Isles and Calhoun) in 1933 and continued through 1938. During the 1950s, the Prudential Insurance Building began discharging 50 thousand gallons of cooling water per day into Brownie Lake. During this time- period, a link was created between Brownie Lake and Bassett’s Creek that provided water to the Chain of Lakes during times of low water levels. In 1966, a pumping station was constructed at the Mississippi River to augment flow in Bassett’s Creek. Water levels in the Chain of Lakes were regulated by pumping from the Mississippi River into Brownie Lake until 1990.

Brownie Lake is on an every other year sampling schedule and was not sampled in 2015. All water quality data presented pertains to the 2014 sampling season. Figure 3-2 shows the bathymetric map and Table 3-1 shows the morphometric data for Brownie Lake.

Table 3-1. Brownie Lake morphometric data.

Surface Mean Watershed: Residence Max Littoral Volume Watershed Area Depth Lake Area Time Depth (m) Area* (m3) Area (acres) (acres) (m) (ratio) (years) 18 6.8 15.2 39% 4.98x105 369 20.5 2.0 * Littoral area defined as less than 15 feet deep.

2015 Water Resources Report – Minneapolis Park & Recreation Board Page 3-2

Figure 3-2. Bathymetric map of Brownie Lake.

LAKE LEVEL

The Ordinary High Water Level (OHW) for Brownie Lake, as determined by the MDNR, is 853 ft (msl). The OHW is defined as the elevation where high water levels can be maintained for a long enough a period of time to leave evidence of the water level on the landscape.

See Section 4, Lake Calhoun for more information on water levels in the Chain of Lakes.

2015 Water Resources Report – Minneapolis Park & Recreation Board Page 3-3 WATER QUALITY TRENDS – TROPHIC STATE INDEX (TSI)

Figure 3-3 shows the Brownie Lake TSI scores and linear regression. The 2014 TSI score for Brownie Lake was 54 and the lowest score since 1993, when sampling began. There is no significant trend in TSI scores over the last 21 years (p > 0.05); however, Brownie is only sampled every-other year. Brownie Lake is scheduled to be sampled again in 2016. A detailed explanation of TSI can be found in Section 1.

Figure 3-3. Brownie Lake TSI scores and linear regression.

Brownie Lake falls near the 50th percentile category for lakes in this ecoregion, based on calculations from the Minnesota Lake Water Quality Assessment Data Base Summary (MPCA, 2004).

BOX AND WHISKER PLOTS

The box and whisker plots in Figure 3-4 show the distribution of data for Secchi depth, chlorophyll- a, and total phosphorus sampling from 2005 to 2014. The horizontal line crossing the graph represents the MPCA eutrophication standard for deep lakes. Data for the entire period of record presented in box and whisker plot format is available in Appendix A. Long-term lake monitoring is necessary to evaluate the seasonal and year-to-year variations seen in each lake and predict trends. A detailed explanation of box and whisker plots can be found in Section 1.

Water transparency in Brownie Lake in 2014 was similar to previous years with an average Secchi depth of 1.4 meters. Algal biomass, as measured by chlorophyll-a concentration, and total phosphorus was lower than 2012 and similar to the mid-2000s. Brownie met the MPCA eutrophication standard for chlorophyll-a and total phosphorus, but not Secchi transparency. Due to Brownie Lake’s permanent stratification, it may not be reasonable to compare Brownie Lake to the deep lake standard. A better measure of the health of Brownie Lake may be to look at long-term trends, which show no significant change over the past 20 years (p > 0.05).

It is difficult to compare Brownie Lake to other Minneapolis Lakes since it is meromictic and is only sampled once per month rather than twice per month that is usual with most of the other lakes. The only other meromictic lake in Minneapolis is Spring Lake.

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Figure 3-4. Brownie Lake box and whisker plots of TSI data for the past ten years. Horizontal lines represent MPCA eutrophication standard for deep lakes. Data for the entire period of record can be found in Appendix A.

2015 Water Resources Report – Minneapolis Park & Recreation Board Page 3-5 WINTER ICE COVER

Ice came off Brownie Lake on March 31, 2015, which was four days earlier than average. Ice came on the lake December 21, 2015, which was 22 days later than average and the latest recorded ice-on date. See Section 1 for details on winter ice cover records and Section 18 for a comparison with other MPRB lakes.

PHYTOPLANKTON

Phytoplankton and zooplankton are the microscopic plant and animal life that form the foundation of the food web in lakes. Figure 3-5 shows the Secchi transparency, chlorophyll-a concentration, and relative abundance of phytoplankton divisions for the 2014 sampling season. No zooplankton samples were collected from Brownie in 2014 due to low zooplankton densities in the past. In 2008, zooplankton tows yielded low concentrations compared to other Minneapolis lakes.

Water transparency fluctuated between 0.8 meters to 2.4 meters, with the lowest transparency in early spring and greatest transparency in June (Figure 3-5a). The low Secchi depth in May was associated with low chlorophyll-a concentration and a large abundance of haptophytes and diatoms (Bacillariophyta, Figures 3-5b, c). The highest chlorophyll-a values of the season occurred in July and September comprised of mainly green algae (Chlorophyta) and blue-green algae (Cyanophyta) respectively. Surprisingly, blue green algae, a group typically characteristic of warm stratified waters in the summer, were abundant in March and then again in September. Cryptomonads (Cryptophyta) were present throughout the year, but were at their greatest abundance in June.

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Figure 3-5. Secchi transparency (a), chlorophyll-a concentration (b), and relative abundance of phytoplankton (c) during the 2014 Brownie Lake sampling season. Note that the Secchi depth axis is reversed.

2015 Water Resources Report – Minneapolis Park & Recreation Board Page 3-7 WATER QUALITY IMPROVEMENT PROJECTS

The MPRB and other surrounding landowners have completed several projects improving the Brownie Lake basin. In 2007, the Target Corporation rehabilitated a stormwater pipe and restored disturbed hillside vegetation on the west side of the lake. City of Minneapolis Public Works and the MPRB worked together to solve an erosion problem on the east side of Brownie Lake in 2008. The two organizations restored an eroded area and replaced an exposed and eroding stormwater outlet with a buried drop-structure and pipe.

In March 2012, the MPRB Board of Commissioners approved an Area Plan for Brownie Lake to improve the land and park amenities surrounding the lake, including path and bike trail improvements and a new canoe launch. Trail improvements, a pedestrian bridge, a new canoe launch, tree planting and landscaping were completed in 2014.

2015 Water Resources Report – Minneapolis Park & Recreation Board Page 3-8 4. LAKE CALHOUN / BDE MAKA SKA

HISTORY

Lake Calhoun is the largest lake in the Minneapolis Chain of Lakes (Figure 4-1). It receives water from Lake of the Isles and discharges water through a weir and open channel to Lake Harriet. The lake has a multitude of recreational opportunities including personal watercraft, sail boat buoy rentals, three public beaches, fishing, and picnicking. The Minneapolis Chain of Lakes Regional Park is the most visited park in the State of Minnesota with nearly 5.5 million user visits a year (Met Council, 2015).

Figure 4-1. Geese flying over Lake Calhoun at sunset.

The lake formerly known as Mde Medoza (Lake of the Loons) and Bde Maka Ska (White Earth Lake) was renamed after John Caldwell Calhoun after he established a military post at Fort Snelling while Secretary of War under President Monroe. In 2015, the Dakota name for the lake, Bde Maka Ska, was added to signs around the lake to honor the Dakota people and educate the public about the lake’s Dakota name.

The lake and adjacent property were acquired by the Minneapolis Park and Recreation Board (MPRB) between 1883 and 1907 at a cost of $130,000. Similar to other lakes in the Minneapolis Chain of Lakes Lake, Lake Calhoun was dredged and surrounding wetland areas were filled (~35 acres) in the early part of the 20th century. Nearly 1.5 million cubic yards of soil were placed on the shoreline between 1911 and 1924.

An effort was made to connect Lake of the Isles and Lake Calhoun after wet years in the early 1900s increased interest in water related activities. A water connection between Isles and Calhoun was created in 1911 after the MRPB received numerous requests and petitions to join the lakes. A connection between Lake Calhoun and Lake Harriet was pondered but was never implemented due to a five foot elevation difference between the lakes. In 1967, a pipeline and pumping station were

2015 Water Resources Report – Minneapolis Park & Recreation Board Page 4-1 constructed between Lakes Calhoun and Harriet to help regulate water elevations in the Chain of Lakes. Between 1999 and 2001, the outlet was partially daylighted and converted to a gravity-flow connection.

Studies have shown that water quality in Lake Calhoun has degraded with human activity. In 1973, Shapiro and Pfannkuch found that phosphorus levels in the sediment were about 80% higher than they had been in the prior 80 to 90 years. Total phosphorus in the water column had also increased to 50 – 60 μg/L by the 1970s from pre-industrial levels of between 16 – 19 μg/L (Brugam and Speziale, 1983). The increases in sediment and water column phosphorus appear to be due to European settlement and land clearing for agriculture in the watershed. The construction and connection of storm sewers to Lake Calhoun (1910 to 1940) is also thought to have had a negative impact on water quality. A study by Klak (1933) showed that cyanobacteria were dominant by the early 1930s in Lake Calhoun, indicating possible nutrient enrichment.

Water quality restoration projects throughout the 1990s and early 2000s have improved water quality in Lake Calhoun. A detailed Clean Water Partnership diagnostic study conducted in 1991 determined that phosphorus input to the Chain of Lakes should be reduced to increase water quality. Best management practices (BMP) were then implemented for Calhoun and included: public education, increased street sweeping, improved storm-water treatment including constructed wetlands (1999), grit chambers (1995, 1998, 1999), and an aluminum sulfate (alum) treatment to limit internal loading of phosphorus in 2001. Current data analysis confirms that the BMPs are having a positive effect and that water quality in Lake Calhoun is at, or even slightly better than historic conditions. For example, Lake Calhoun’s observed TP is similar to the TP level from 1750 and 1800 based on diatom reconstruction of sediment cores (Heiskary et al., 2004).

Lake Calhoun is a deep, dimictic, glacial kettle lake that typically remains stratified until late October. Table 4-1 contains the morphometric data for Lake Calhoun. Figure 4-2 shows the bathymetric map of Lake Calhoun.

Table 4-1. Lake Calhoun morphometric data.

Surface Mean Maximum Watershed: Residence Littoral Volume Watershed Area Depth Depth Lake Area Time Area* (m3) Area (acres) (acres) (m) (m) (ratio) (years) 421 10.6 27.4 27% 1.80x107 2,992 7.1 4.2 * Littoral area was defined as less than 15 feet deep.

2015 Water Resources Report – Minneapolis Park & Recreation Board Page 4-2

Figure 4-2. Bathymetric map of Lake Calhoun.

2015 Water Resources Report – Minneapolis Park & Recreation Board Page 4-3 LAKE LEVEL

The lake level for the Upper Chain of Lakes (Brownie, Calhoun, Cedar, and Isles) is measured at Lake Calhoun. The four lakes are connected by channels and the gage at Lake Calhoun represents the level at each of the four lakes. The designated Ordinary High Water Level (OHW) for Lake Calhoun is 853 feet above mean sea level. The outlet elevation for Lake Calhoun is 851.85 ft above mean sea level. Lake levels for the Upper Chain of Lakes are shown in Figure 4-3. Following two years with heavy spring rains and high lake levels, the 2015 levels were lower with two peaks in July and November due to above average precipitation during those months.

Figure 4-3. Lake levels for the Minneapolis Upper Chain of Lakes (Brownie, Cedar, Isles and Calhoun). Horizontal line represents Lake Calhoun Ordinary High Water Level (853 ft msl).

WATER QUALITY TRENDS – TROPHIC STATE INDEX (TSI)

Figure 4-4 shows historical Lake Calhoun TSI scores and trend line. There has been a significant decrease in TSI since 1991 (p < 0.05) with a TSI score of 42 in 2015. This decrease has followed multiple rehabilitation efforts since 1995. The lake is now mesotrophic with moderately clear water and some algae.

Recent lake conditions have remained relatively stable with a TSI score 10 to 15 units lower (better) than the early 1990s, before the lake and watershed improvement projects from the Clean Water Partnership. In comparison to other lakes in this ecoregion, Calhoun is in the top 5% of TSI scores based on calculations using the Minnesota Lake Water Quality Data Base Summary (MPCA, 2004). A detailed explanation of TSI can be found in Section 1.

2015 Water Resources Report – Minneapolis Park & Recreation Board Page 4-4

Figure 4-4. Lake Calhoun TSI scores and linear regression. The blue square highlights the 2001 alum treatment.

BOX AND WHISKER PLOTS

The box and whisker plots in Figure 4-5 show the data distribution for Secchi transparency, chlorophyll-a, and total phosphorus for the past 10 years. Red horizontal lines on the graphs indicate the MPCA deep lake standards. A detailed explanation of box and whisker plots can be found in Section 1. Data from the entire period of record in box and whisker plot format can be found Appendix A.

Water transparency, chlorophyll-a, and total phosphorus in 2015 were similar to the previous 10 years and all parameters met the MPCA eutrophication standards. The one high total phosphorus sample occurred when the lake was ice covered when nutrient concentrations at the surface can be higher due to mixing with nutrient rich bottom waters. When comparing the boxplots in Figure 4-5 to those in Appendix A, it becomes obvious that the 2001 alum treatment had a profound effect on parameters measured in Lake Calhoun, indicating an overall water quality improvement.

2015 Water Resources Report – Minneapolis Park & Recreation Board Page 4-5

Figure 4-5. Lake Calhoun box and whisker plots of TSI data for the past 10 years. Horizontal lines represent MPCA eutrophication standard for deep lakes. See Appendix A for the entire period of record.

2015 Water Resources Report – Minneapolis Park & Recreation Board Page 4-6 BEACH MONITORING

In 2015, bacteria levels were monitored at Lake Calhoun at three different locations: Calhoun 32nd Street Beach on the east side, Calhoun Main Beach on the north side, and Calhoun Thomas Beach on the south side. As shown in Table 4-2, the season long geometric means for Escherichia coli (E. coli) for Calhoun Main Beach was low; meanwhile, 32nd Street Beach and Thomas Beach were moderately low. High bacteria levels closed Thomas Beach for one day in 2015, most likely due to a high amount of geese in the area during the time the samples were taken. E. coli concentrations had dropped to 32 MPN/100 mL the following afternoon and below 5 MPN/100 mL two days later, highlighting how quickly bacteria levels can change in the lake. See Section 19 for more information on beach monitoring.

Table 4-2. Summary of E. coli (MPN per 100 mL) data for Lake Calhoun beaches in 2015.

Statistical Calculations Calhoun 32nd Calhoun Main Calhoun Thomas Number of Samples 13 13 13 Minimum 7 3 3 Maximum 353 207 1484 Median 50 15 56 Mean 107 57 265 Geometric Mean 60 21 59 Max 30-Day Geo Mean 120 56 101 Standard Deviation 112 77 455

Figure 4-6 illustrates the box and whisker plots of E. coli sampling results (per 100 mL of lake water) for Lake Calhoun beaches from 2006 to 2015. The box and whisker plots show the scatter in the dataset over several years. The dashed light red line represents the E. coli standard for the 30-day geometric mean (126 MPN/100mL), while the solid dark red line represents the single-sample maximum standard (1260 MPN/100mL). The 2015 E. coli results generally had higher variation than previous years at Calhoun Main and Thomas Beaches. Thomas Beach had higher E. coli concentrations than historic levels for the second straight year.

2015 Water Resources Report – Minneapolis Park & Recreation Board Page 4-7

Figure 4-6. Box and whisker plots of E. coli results (per 100 mL) for Lake Calhoun beaches from data collected between 2006 and 2015. The dashed horizontal line represents the E. coli standard for the 30-day geometric mean (126 MPN/100mL) and the solid horizontal line represents the single-sample maximum standard (1260 MPN/100mL). Note the log scale on the Y-axis. From 2006-2009 E. coli concentrations were determined as colony forming units (CFU/100ml).

2015 Water Resources Report – Minneapolis Park & Recreation Board Page 4-8

LAKE AESTHETIC AND USER RECREATION INDEX (LAURI)

Figure 4-7 shows the 2015 LAURI for Lake Calhoun. Lake Calhoun was rated excellent in aesthetics, habitat quality, clarity, and recreational access. Elevated E. coli levels at Thomas and 32nd St beaches led to a good rating in public health. Dettails on LAURI can be fouund in Section 1 and comparisons with other lakes can be found in Sectioon 18.

Figure 4-7. The 2015 LAURI for Lake Calhoun.

2015 Water Resources Report – Minneapolis Park & Recreation Board Page 4-9

WINTER ICE COVER

Ice came off Lake Calhoun on April 2, 2015, which was seven days later than average. Lake ice did not fully cover the lake until January 4, 2016, which was 22 days later than the average. (See Figures 4-8 and 4-9 below).

While there is a lot of fluctuation in the data, there is a significant trend towards an earlier ice-off (p < 0.05) since 1940 (Figure 4-8). The running average ice-off date has shifted to earlier dates, floating around April 13th in the 1970s to April 8th for the past 10 years. The histogram in Figure 4- 8 shows the majority of ice-off dates occurring in early to mid-April over the past 70 years, with a few years with early ice-off dates in March.

Figure 4-8. Lake Calhoun ice-off dates and frequency of the occurrence of ice-off on particular dates for all the years of record. 66 recorded ice-off dates exist over the past 70 years.

Fewer observations for ice-on dates exist for Lake Calhoun. While there is no significant trend in ice-on date (p > 0.05) since 1962, the five latest ice-on dates have occurred since 2001 (Figure 4-9). The histogram in Figure 4-9 shows Lake Calhoun is typically frozen in early to mid-December over the past 53 years of observation, with a few ice-on dates in January. See Section 1 for details on winter ice cover records and Section 18 for a comparison with other lakes.

Figure 4-9. Lake Calhoun ice-on dates and frequency of the occurrence of ice-on on particular dates for all the years of record. 46 ice-on records exist.

2015 Water Resources Report – Minneapolis Park & Recreation Board Page 4-10

EXOTIC AQUATIC PLANT MANAGEMENT

The Minnesota Department of Natural Resources (MDNR) requires a permit to remove or control Eurasian watermilfoil. These permits limit the area from which milfoil can be harvested in order to protect fish habitat. The permits issued to the MPRB allow for harvesting primarily in swimming areas, boat launches, and in areas where public recreational access is needed. In 2015, the permitted area on Lake Calhoun was 47 acres which is about 40% of the littoral zone (area 15 feet or shallower). For more information on aquatic plants see Section 1 and Section 20.

PHYTOPLANKTON AND ZOOPLANKTON

Phytoplankton and zooplankton are the microscopic plant and animal life that form the basic food web of lake ecology. Figures 4-10 shows the Secchi transparency, chlorophyll-a concentrations, and relative abundance of phytoplankton division during the 2015 sampling season.

Water clarity was greater than 2 meters for the entire sampling season in 2015, with the greatest transparency of 5.2 meters in early June (Figure 4-10a). Chlorophyll-a concentrations were low throughout the season as well (Figure 4-10b). The highest algal biomass occurred in March while the lake was still ice covered (9 µg L-1) and was characterized by cryptomonads (Cryptophyta) and diatoms (Bacillariophyta; Figure 4-10b, c). The phytoplankton community in Lake Calhoun was largely dominated by blue green algae for most of the year, even the winter sample (Figure 4-10c). Diatoms and cryptomonads (Cryptophyta) were abundant in the spring and then again in late October. Both groups are high quality food for zooplankton. Dinoflagellates had a small bloom at the beginning of September.

Figure 4-11 shows the zooplankton distribution in Lake Calhoun sampled throughout 2015. Rotifers comprised the entire zooplankton community in the spring and were at their highest density in April, May, August, and October. Nauplii (juvenile stages of zooplankton) were found at their highest numbers in the May sample, tapering off throughout the rest of the season. Cladocerans and protozoa were at their highest abundance in July. Cyclopoids and calanoids were present in low numbers from April through October.

2015 Water Resources Report – Minneapolis Park & Recreation Board Page 4-11

Figure 4-10. Secchi transparency (a), chlorophyll-a concentration (b), and relative abundance of phytoplankton (c) during the 2015 Lake Calhoun sampling season. Note that the Secchi depth axis is reversed.

2015 Water Resources Report – Minneapolis Park & Recreation Board Page 4-12

Figure 4-11. Lake Calhoun 2015 zooplankton density.

FISH STOCKING

Additional information and a definition of fry, fingerling, yearling and adult fish can be found in Section 1.

Lake Calhoun was stocked by the MDNR in: 1999 with 71 adult Muskellunge, 125 fingerling Muskellunge. 2000 with 107 adult Muskellunge, 1,590 yearling Walleye. 2001 with 12,654 fingerling Walleye. 2002 with 500 fingerling Tiger Muskellunge. 2003 with 5,545 fingerling Walleye. 2005 with 500 fingerling Tiger Muskellunge. 2006 with 2,356 fingerling Walleye. 2007 with 500 fingerling Tiger Muskellunge. 2009 with 480 fingerling Tiger Muskellunge, 9,991 fingerling Walleye, 248 yearling Walleye. 2010 with 127 fingerling Muskellunge. 2012 with 123 fingerling Muskellunge, 12,684 yearling Walleye. 2015 with 40 fingerling Walleye, 1613yearling Walleye

2015 Water Resources Report – Minneapolis Park & Recreation Board Page 4-13

5. CEDAR LAKE

HISTORY

Like the other lakes in the Chain of Lakes, Cedar Lake was altered from its natural state when it was dredged between 1911 and 1917. Channels connecting Cedar Lake to Lake of the Isles and to Brownie Lake were created in 1913 and 1916. The Lake of the Isles connection caused the water level in Cedar Lake to drop six feet. The new water elevation changed the shape of the lake most noticeably turning Louis Island on the west side of the lake into a peninsula. Figure 5-1 shows one of Cedar Lake’s three beaches.

Clean Water Partnership projects were implemented to improve water quality at Cedar Lake. Constructed wetlands (1995) and an aluminum sulfate (alum) treatment (1996) were best management practices (BMPs) implemented to improve water quality in the lake. The 1996 alum treatment improved phosphorus levels at the surface and the hypolimnion and was predicted to have a treatment life span of at least seven years (Huser, 2005).

Cedar Lake is a kettle lake and is typically dimictic; however, there is evidence that in some years the lake may mix during the late summer and then re-stratify (Lee and Jontz, 1997). Figure 5-2 shows a bathymetric map of Cedar Lake. Table 5-1 shows the Cedar Lake morphometric data.

Figure 5-1. View of Cedar Lake from Main Beach.

Table 5-1. Cedar Lake morphometric data.

Surface Mean Watershed: Residence Max Depth Littoral Volume Watershed Area Depth Lake Area Time (m) Area* (m3) Area (acres) (acres) (m) (ratio) (years) 170 6.1 15.5 37% 4.26x106 1,956 11.5 2.7 * Littoral area defined as less than 15 feet deep.

2015 Water Resources Report – Minneapolis Park & Recreation Board Page 5-1 Cedar Lake Bathymetry 1:10,000

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Bathymetry of Cedar Lake. Fieldwork by MDNR 1958. Depth Contours Contours digitized and provided by MDNR. Streets Additional data provided by the City of Minneapolis.

Figure 5-2. Bathymetric map of Cedar Lake.

LAKE LEVEL

The designated Ordinary High Water Level (OHW) for Cedar Lake is 853 feet above msl. Section 4, Lake Calhoun includes more information on historic Chain of Lakes water level information.

2015 Water Resources Report – Minneapolis Park & Recreation Board Page 5-2 WATER QUALITY TRENDS – TROPHIC STATE INDEX (TSI)

The 2015 TSI score for Cedar Lake was 51, putting Cedar in the top 25% of TSI scores compared to other lakes in the ecoregion (based on calculations from the Minnesota Pollution Control Agency, using the Minnesota Lake Water Quality Data Base Summary, 2004). The TSI scores for all monitored years with a linear regression are shown in Figure 5-3. Restoration efforts begun in 1994 have helped improve water quality in the lake. Although there was an initial decrease in TSI after restoration projects, there has been no significant trend in TSI from 1991-2014 (p > 0.05). Cedar Lake is currently mesotrophic with moderately clear water and some algae. A detailed explanation of TSI can be found in Section 1.

Figure 5-3. Cedar Lake TSI scores and linear regressions from 1991-2015. The alum treatment year is indicated with a blue square.

BOX AND WHISKER PLOTS

The box and whisker plots in Figure 5-4 show the data distribution for Secchi transparency, chlorophyll-a, and total phosphorus for Cedar Lake for the past decade. Horizontal lines on the graphs indicate the MPCA deep lake standards. A detailed explanation of box and whisker plots can be found in Section 1. Data in box and whisker plot format for the entire period of record can be found in Appendix A.

Cedar Lake water transparency in 2015 was similar to the past two years and slightly worse than clarity from 2007-2012; however, chlorophyll-a and total phosphorus levels were consistent with levels from the past decade. Cedar met the MPCA eutrophication standard for chlorophyll-a and total phosphorus, but did not meet the standard for Secchi depth in 2015.

2015 Water Resources Report – Minneapolis Park & Recreation Board Page 5-3

Figure 5-4. Box and whisker plot data for Cedar Lake for the past decade. Horizontal lines represent MPCA eutrophication standard for deep lakes. See Appendix A for the entire period of record.

2015 Water Resources Report – Minneapolis Park & Recreation Board Page 5-4 BEACH MONITORING

Escherichia coli (E. coli) levels were sampled at three different locations around Cedar Lake: Cedar Main Beach, Cedar Point Beach, and East Cedar Beach (Hidden). All Cedar Lake beaches remained open for the entire 2015 season. As shown in Table 5-2, the season-long geometric means for E. coli were relatively low at all of the Cedar Lake beaches. East Cedar Beach was opened as a supervised public beach for the first time in 2007 and typically has had some of the lowest E. coli count values for all MPRB beaches.

Table 5-2. Summary of 2015 E. coli results (MPN per 100 mL) for Cedar Lake beaches.

Statistical Calculations Cedar Main Cedar Point East Cedar

Number of Samples 13 13 13 Minimum 4 2 1 Maximum 155 158 150 Median 31 60 10 Mean 43 59 32 Geometric Mean 29 30 10 Max 30-Day Geo Mean 51 86 28 Standard Deviation 42 45 47

Figure 5-5 shows box and whisker plots of E. coli sampling results for 2006 - 2015. The dashed red line represents the E. coli standard for the 30-day geometric mean (126 MPN/100mL), while the solid red line represents the single-sample maximum standard (1260 MPN/100mL). Cedar Point beach had higher E. coli levels that previous years, but were still below state and federal standards. Both Cedar Main and East Cedar beaches had comparable levels to previous years. Additional information on beach monitoring can be found in Section 19.

2015 Water Resources Report – Minneapolis Park & Recreation Board Page 5-5

Figure 5-5. Box and whisker plots of E. coli results (per 100 mL) for Cedar Lake beaches for 2006 -2015. The dashed horizontal line represents the E. coli standard for the 30- day geometric mean (126 MPN/100mL) and the solid horizontal line represents the single-sample maximum standard (1260 MPN/100mL). Note the log scales on each y-axis. From 2006-2009 E. coli concentrations were determined as colony forming units (CFU/100ml).

2015 Water Resources Report – Minneapolis Park & Recreation Board Page 5-6 LAKE AESTHETIC AND USER RECREATION INDEX (LAURI)

The 2015 LAURI for Cedar Lake is presented in Figure 5-6. Cedar Lake scored “excellent” in aesthetics, habitat quality, public health, and recreational aaccess and “good” in water clarity. See Section 1 for details on the LAURI index.

Figure 5-6. The 2015 LAURI for Cedar Lake.

2015 Water Resources Report – Minneapolis Park & Recreation Board Page 5-7

WINTER ICE COVER

Ice came off Cedar Lake on April 1, 2015, which was six days earlier than average. Ice was back on the lake by December 21, 2015, which is 18 days later than the average ice-on date and tied for the latest ice-on date recorded. See Section 1 for details on winter ice-cover records and Section 18 for a comparison with other lakes.

EXOTIC AQUATIC PLANT MANAGEMENT

The MDNR requires a permit to remove or control Eurasian watermilfoil. The permit limits the area from which milfoil can be harvested in order to protect fish habitat. The permits issued to the MPRB allowed for harvesting primarily in swimming areas, boat launches, and shallow areas where recreational access was necessary. In 2015, the permitted area on Cedar Lake was 19 acres which is approximately 25% of the littoral zone of the lake (area shallower than 15 feet). See Section 1 for details on aquatic plants.

PHYTOPLANKTON AND ZOOPLANKTON

Phytoplankton and zooplankton are the microscopic plant and animal life that form the foundation of the food web in lakes. Figure 5-7 shows the Secchi transparency, chlorophyll-a concentrations, and relative abundance of phytoplankton division during the 2015 sampling season. Figure 5-8 shows the zooplankton distribution over 2015.

Secchi depth at the beginning of the season was low (1.2 m), but chlorophyll-a concentrations were also low (3.2 µg L-1), indicating non algal turbidity may have influenced water transparency in the early spring (Figure 5-7a, b). These early spring samples were a mixture of diatoms (Bacillariophyta), green algae (Chlorophyta), cryptophytes (Cryptophyta), haptophytes (Haptophyta), and dinoflaggelates (Pyrrhophyta, Figure 5-6c). Similar to previous years, there was a brief time in early June when water transparency exceeded 4 meters, but the remainder of the season Secchi depth slowly declined to less than 1 meter once blue green algae (Cyanobacteria) became more abundant (Figure 5-7a-c).

Zooplankton samples were taken once per month between April and October during the 2015 sampling season and results are displayed in Figure 5-8. Concentrations of juvenile zooplankton and nauplii were abundant throughout the season with the highest density in July. Rotifers, which are a group of small zooplankton, were present throughout the season and were most abundant in spring and late fall. Cladoceran and cyclopoid numbers remained fairly stable throughout the season. Calanoids were present at low levels and Protozoa were present only in July.

2015 Water Resources Report – Minneapolis Park & Recreation Board Page 5-8

Figure 5-7. Secchi transparency (a), chlorophyll-a concentration (b), and relative abundance of phytoplankton (c) during the 2015 Cedar Lake sampling season. Note that the Secchi depth axis is reversed.

2015 Water Resources Report – Minneapolis Park & Recreation Board Page 5-9

Figure 5-8. 2015 Cedar Lake zooplankton distribution.

FISH STOCKING

Additional information and a definition of fry, fingerling, yearling, and adult fish sizes can be found in Section 1.

Cedar Lake was stocked by MDNR in: 1998 with 299 fingerling Muskellunge. 2001 with 200 fingerling Tiger Muskellunge. 2004 with 200 fingerling Tiger Muskellunge. 2005 with 1,168 fingerling Walleye. 2007 with 160 fingerling Tiger Muskellunge and 2,022 fingerling Walleye. 2009 with 2,835 fingerling Walleye and 115 yearling Walleye. 2010 with 67 fingerling Muskellunge. 2011 with 3,828 fingerling Walleye. 2012 with 63 fingerling Muskellunge. 2013 with 3.640 fingerling Walleye. 2015 with 167 yearling Walleye.

2015 Water Resources Report – Minneapolis Park & Recreation Board Page 5-10 6. DIAMOND LAKE

HISTORY

Diamond Lake is a small shallow water body predominantly surrounded by residential neighborhoods and parkland (Figure 6-1). The National Wetlands Inventory classifies Diamond Lake as a permanently flooded lacustrine/limnetic system with an unconsolidated bed (L1UBH). The fringe of Diamond Lake is classified as palustrine semipermanently flooded wetland with emergent vegetation (PEMF) (USFWS, 2012).

Diamond Lake and surrounding park areas were donated to the MPRB between 1926 and 1936. In 1937, a project was proposed to dredge Diamond Lake, generating fill to deposit in Pearl Lake to create Pearl Park. However, the Board voted against the project and decided to use fill from airport properties instead. A drain from Pearl Park was installed to divert water to Diamond Lake and prevent flooding in the park.

Water levels in Diamond Lake have fluctuated due to land use changes in the surrounding watershed. In 1940, the City of Minneapolis installed storm sewers and by 1941, 800 acres of developed land was draining into Diamond Lake causing drastic water elevation fluctuations. In 1942, the Works Progress Administration (WPA) constructed an overflow to control water elevation and an outflow pipe that carried water from the northeast shore to Minnehaha Creek. Construction of Interstate 35W during the 1960s added several miles of highway runoff to Diamond Lake. In 1991, the MPRB placed a weir at 822.0 ft msl allowing for higher water than the previous outlet which was 820.1 ft msl (110.3 feet above city datum). The increase in water elevation was made to encourage establishment of aquatic plants and to restore wildlife habitat in Diamond Lake.

Figure 6-1. Diamond Lake in Fall 2013.

In 1953, the Minnesota Department of Natural Resources (MDNR) completed a water quality survey

2015 Water Resources Report – Minneapolis Park & Recreation Board Page 6-1 and determined that the lake could not be considered a fish supporting lake due to the lack of oxygen during the winter months (MDNR, 1953). MPRB sampling has confirmed that Diamond Lake freezes to the bed during some winters. In 2007, construction began on the 35W/HWY62 improvement project that changed the drainage areas in the Diamond Lake watershed. Figure 6-2 shows a map for Diamond Lake. Table 6-1 shows morphometric data for Diamond Lake.

Table 6-1. Diamond Lake morphometric data.

Surface Mean Watershed: Ordinary Max Littoral Volume Watershed Area Depth Lake Area High Water Depth (m) Area* (m3) Area (acres) (acres) (m) (ratio) Level (msl) 41 0.9 2.1 100% 7.15x104 669 16.3 822.32 * Littoral area is defined as less than 15 feet deep.

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2015 Water Resources Report – Minneapolis Park & Recreation Board Page 6-2 LAKE LEVEL

The lake level for Diamond Lake is measured at a gage near the Diamond Lake Lutheran Church and results are shown in in Figure 6-3. The designated Ordinary High Water Level (OHW) for Diamond Lake is 822.32 feet above mean sea level. Lake levels started the season low due to the lack of significant snowmelt and increased with rainfall in July and September. Diamond Lake froze near its ordinary high water level.

Figure 6-3. Diamond Lake levels from 2000 to the present. Horizontal line represents Diamond Lake ordinary high water elevation (822.5 ft msl).

WATER QUALITY TRENDS – TROPHIC STATE INDEX (TSI)

The 2015 TSI score for Diamond Lake was 67. Figure 6-4 shows the TSI scores and trend from 1992–2015 at Diamond Lake. A detailed explanation of TSI can be found in Section 1.

Carlson’s TSI Index would classify Diamond Lake as eutrophic. However, Carlson’s index was developed for lakes without non-algal turbidity and with low macrophyte populations. Diamond Lake does not meet these criteria. It is a fertile, very shallow water body with high non-algal turbidity and thick aquatic plant beds. Secchi depth was not used in TSI calculations of Diamond Lake, since the lake is often either clear to the bottom or the Secchi disk is obscured by dense aquatic plant growth. In 2004, the sampling location changed from a grab sample off a dock on the northeast side of the lake to a grab sample over the deep spot in the southern part of the lake from a canoe. There is no significant trend in the TSI score for Diamond Lake from 1992-2015 (p > 0.05); however, there is a significant decrease in TSI score from 2004-2015 (p < 0.05) indicated by the red line in Figure 6-4. This phenomenon could be due to the change in sampling location or to improvements due to water quality infrastructure constructed for the 35W/HWY62 project.

2015 Water Resources Report – Minneapolis Park & Recreation Board Page 6-3

Figure 6-4. Diamond Lake TSI scores and linear regression analysis from 1992 to 2015. The linear regression line for the entire record is colored blue, while the linear regression line since 2004 is colored red.

BOX AND WHISKER PLOTS

The box and whisker plots in Figure 6-5 show the data distribution for chlorophyll-a and total phosphorus levels in Diamond Lake over the past ten years. Data from the entire period of record in box and whisker plot format can be found in Appendix A. A detailed explanation of box and whisker plots can be found in Section 1.

Diamond Lake has limited Secchi transparency data due to its shallowness and high macrophyte density. During 2015, only two Secchi disk readings were taken; otherwise, the lake was either clear to the bed or obscured by thick aquatic plant growth.

Chlorophyll-a and total phosphorus levels began to decrease in the mid-2000s. This phenomenon could be due to construction activities from the 35W/HWY 62 project and subsequent slope stabilization and constructed best management practices. Continued monitoring will help to determine if the trend will continue or whether the changes in nutrient levels are part of the natural fluctuations of the wetland. Generally data from Diamond Lake is more variable and contains more scatter than deeper lakes. Increased scatter in the Diamond Lake data could be influenced by seasonal water level changes and stormwater influx.

2015 Water Resources Report – Minneapolis Park & Recreation Board Page 6-4

Figure 6-5. Box and whisker plots of Diamond Lake data from 2006-2015. See Appendix A for the entire period of record.

WINTER ICE COVER

In the spring, ice came off of Diamond Lake on March 21, 2015, 12 days earlier than average. Ice came back on to Diamond Lake on December 18, 2015, 19 days after the average ice-on date. See Section 1 for details on winter ice cover records and Section 18 for a comparison with other lakes.

PHYTOPLANKTON

Phytoplankton are the microscopic plant life that form the foundation of the food web in lakes. In Figure 6-6 shows the chlorophyll-a concentrations and relative abundance of phytoplankton division during the 2015 sampling season in Diamond Lake. Zooplankton are not sampled at Diamond Lake.

Chlorophyll-a was low (< 10 µg L-1) during the spring and comprised mainly of cryptomonads (Cryptophyta), euglenoids (Euglenophyta), and green algae (Chlorophyta). In July the chlorophyll-a concentrations began to rise and exceeded 70 µg L-1 at the end of August. During this time there was a decrease in cryptomonads and an increase in green and blue green algae (Cyanophyta). Chrysophytes (Chrysophyta) were periodically abundant throughout the season. Chlorophyll-a levels dropped the remainder of the season and cryptomonads were abundant again in October (Figure 6- 6a, b). Unlike most of the other MPRB lakes, euglenoids were present at high levels in the late

2015 Water Resources Report – Minneapolis Park & Recreation Board Page 6-5 summer. Euglenoids are commonly found in waters rich in nutrients and organic matter around sediments and macrophytes. Also unlike most other Minneapolis lakes, blue-green algae were only present at low levels throughout the summer. Diamond Lake contains high levels of dense plant growth and the phytoplankton collected may partially reflect the community of organisms living attached to plants as well as the free-floating algae community found in most of the other sampled lakes.

Figure 6-6. Chlorophyll-a concentration (a) and relative abundance of phytoplankton (b) during the 2015 Diamond Lake sampling season.

2015 Water Resources Report – Minneapolis Park & Recreation Board Page 6-6 WETLAND HEALTH EVALUATION PROJECT (WHEP)

The wetland fringe of Diamond Lake was evaluated by the Wetland Health Evaluation Project (WHEP) led by Hennepin County and a group of citizen volunteers. Results of the wetland evaluation are presented in Section 21. 2015 was the tenth year that Diamond Lake was evaluated in the WHEP program.

2015 Water Resources Report – Minneapolis Park & Recreation Board Page 6-7 7. GRASS LAKE

HISTORY

Grass Lake was created during the construction of State Highway 62. The highway separated one waterbody into two new lakes: Grass Lake to the north and Richfield Lake to the south. The area is known for bird-watching. Land surrounding the lake is not connected to the Minneapolis Park system and is shown below in Figure 7-1.

Grass Lake was added to the Minneapolis Park & Recreation Board (MPRB) lake sampling program in 2002. It is typically sampled every other year and was not sampled in 2015. All water quality data presented pertains to the 2014 sampling season. Morphometric data for the lake is presented in Table 7-1. Figure 7-2 shows a map of Grass Lake.

Figure 7-1. Photograph of Grass Lake in 2012.

Table 7-1. Grass Lake morphometric data. OHW= Ordinary High Water Level.

Surface Area Mean Depth Maximum Watershed Watershed: Lake OHW (acres) (m) Depth (m) Area (acres) Area (ratio) (msl) 27 0.6 1.5 386 14.3 830.9

2015 Water Resources Report – Minneapolis Park & Recreation Board Page 7-1

Figure 7-2. Grass Lake map.

WATER QUALITY TRENDS – TROPHIC STATE INDEX (TSI)

The TSI Index is also meant to examine lakes without non-algal turbidity and with low macrophyte populations. Grass Lake is a predominantly a Type 5 wetland containing extensive macrophytes and is too shallow to measure the Secchi depth; therefore, Secchi depth was not used in TSI calculations for Grass Lake. A detailed explanation of TSI can be found in Section 1.

The 2014 Grass Lake TSI score was 56 and Figure 7-3 shows the Grass Lake TSI scores for 2002- 2014. This data includes samples from two different locations, potentially biasing the results. The original sample location has been inaccessible since 2008 due to a construction project. There is not significant trend in TSI scores over the last 13 years (p > 0.05); however, Grass is only sampled every-other year. Grass Lake is scheduled to be sampled again in 2016. It appears as though 2003 was an outlier, as subsequent years have clustered between a TSI score of 55 to 65. Additional years of monitoring will be needed to discern a trend from natural variation seen in Grass Lake.

2015 Water Resources Report – Minneapolis Park & Recreation Board Page 7-2

Figure 7-3. Grass Lake TSI scores and linear regression for monitored years from 2002 to 2014. The trend should be viewed with caution since only 7 data points have been calculated and the sampling location changed in 2008.

BOX AND WHISKER PLOTS

Figure 7-4 shows box and whisker plots of the Grass Lake data from 2005 to 2014. A detailed explanation of box and whisker plots can be found in Section 1. Data from the entire period of record in box and whisker format can be found in Appendix A.

Secchi readings are not taken due to the shallowness of the wetland and the sampling location. Grass Lake can freeze to the bed in some years, making it impossible to collect a winter sample. Variations in the Grass Lake data may be due to climatic differences, the monthly sampling regime, or the variability of the wetland.

2015 Water Resources Report – Minneapolis Park & Recreation Board Page 7-3

Figure 7-4. Plots of chlorophyll-a, total phosphorus, and total nitrogen data for Grass Lake.

WINTER ICE COVER

Ice came off Grass Lake on March 23, 2015, eleven days earlier than average. Ice was back on Grass Lake on December 18, 2015, 16 days later than average and the latest ice on recorded since records began in 2002. See Section 1 for details on winter ice cover records and Section 18 for a comparison with other lakes.

2015 Water Resources Report – Minneapolis Park & Recreation Board Page 7-4 PHYTOPLANKTON

Phytoplankton are the microscopic plant life that forms the foundation of the food web in lakes. Figure 7-5 shows the concentration of chlorophyll-a and the relative abundance of phytoplankton divisions in Grass Lake for the 2014 sampling season. Chlorophyll-a levels were low (< 10.5 µg L-1) throughout the open water season (Figure 7-5a). Cryptomonads (Cryptophyta), green algae (Chlorophyta), and diatoms (Bacillariophyta) dominated the phytoplankton assemblage, while blue- green algae were at low abundance throughout the season (Figure 7-5b). The Grass Lake phytoplankton community is similar to Diamond Lake, which is the other shallow wetland sampled this year.

Figure 7-5. Chlorophyll-a concentration (a) and relative abundance of phytoplankton (b) during the 2014 Grass Lake sampling season.

2015 Water Resources Report – Minneapolis Park & Recreation Board Page 7-5 8. Lake Harriet

HISTORY

Lake Harriet is named after Harriet Lovejoy Leavenworth, the wife of Colonel Leavenworth. Colonel W.S. King donated a majority of the lake (360 acres) and surrounding areas (55 acres) to the Minneapolis Park & Recreation Board (MPRB) in 1885. The MPRB acquired the remainder of the surrounding land between 1883-1898 and 1921.

Lake Harriet is a deep kettle lake that generally remains strongly stratified from May through October. The lake offers many recreational activities including sailing, swimming, and fishing. Park patrons enjoy concerts at the bandshell and the many gardens surrounding the lake. In 2006, both of the MDNR-funded floating docks in Lake Harriet were extended. The lake is shown below in Figure 8-1. Figure 8-2 shows a bathymetric map and Table 8-1 shows the morphometric data for Lake Harriet.

Figure 8-1. Lake Harriet sailboat buoy field at sunset in 2016.

There was less dredging and filling at Lake Harriet compared to the other MPRB lakes. A marshland on the northeast corner of the lake was filled to make room for the parkway. The wetland at the north end of the lake that is now Robert’s Bird Sanctuary was deemed too expensive to fill. A proposed channel connecting Lake Harriet with Lake Calhoun was never constructed due to the 5- foot elevation difference between the upper Chain of Lakes and Harriet. Today, after several modifications to the inlet and outlet, there is a 4-foot difference between the two lakes.

2015 Water Resources Report – Minneapolis Park & Recreation Board Page 8-1 Lake Harriet Bathymetry 0 1:10,000

42ND 20

QUEEN 42ND ROSE WAY

UPTON SHERIDAN

LINDEN HILLS

60 42ND WEST LAKE HARRIET 70 43RD 43RD

50

30 44TH 30

30 44TH

30

THOMAS 70 45TH 45TH 60

30

80 15 30

EAST LAKE HARRIET 46TH 46TH 46TH 60

UPTON

47TH 40 47TH 47TH HUMBOLDT

48TH 10 FREMONT 48TH

5 HUMBOLDT 48TH GIRARD

PARK SHERIDAN

IRVING KNOX

0 0.05 0.1 0.2 0.3 0.4 0.5 Miles

Water Bathymetry of Lake Harriet. Fieldwork by MDNR 1981. Depth Contours Contours digitized and provided by MDNR. Streets Additional data provided by the City of Minneapolis.

Figure 8-2. Bathymetric map of Lake Harriet.

Table 8-1. Lake Harriet morphometric data.

Surface Mean Watershed: Residence Max Littoral Volume Watershed Area Depth Lake Area Time Depth (m) Area* (m3) Area (acres) (acres) (m) (ratio) (years) 353 8.7 25.0 25% 1.25x107 1,139 3.2 3.4 * Littoral area defined as less than 15 feet deep.

2015 Water Resources Report – Minneapolis Park & Recreation Board Page 8-2 In 1967, a pumping station and pipeline were constructed between Lakes Harriet and Calhoun in order to control water levels in the upper Chain. In 1999, it was replaced with a gravity outlet, open channel, and pipe connection. The inlet into Lake Harriet consists of a pipe under the water near the boat launch on the northeast corner of the lake. Lake Harriet discharges to Minnehaha Creek through a submerged pipe located at the southern edge of the lake.

Brugam and Speziale (1983) analyzed deep sediment cores and determined that European-American settlement in the 1850s led to increased sedimentation rate due to land clearing and agriculture. Diatom reconstruction of total phosphorus suggests that pre-European phosphorus levels were around 20 µg/L. However, increases in stormsewer discharge since the 1920s led to increased phosphorus levels that peaked in the 1970s. Recent observed data have shown a decline in phosphorus levels since the 1990s and suggest concentrations in Lake Harriet have returned to levels similar to pre- European settlement (Heiskary et al., 2004).

Restoration techniques and best management practices (BMPs) have improved water quality in Lake Harriet. A detailed Clean Water Partnership diagnostic study conducted in 1991 determined that phosphorus input to the Chain of Lakes should be reduced to improve water quality. BMPs implemented included: public education, increased street sweeping, constructed wetlands (1998), and grit chambers (1994-1996). In 2001, an alum treatment was also carried out on areas of the lake shallower than 25 feet to control filamentous algae growth in the littoral zone by limiting the available phosphorus. Not originally intended to do so, the alum had an unexpected benefit of limiting internal phosphorus loading in the lake (Huser, 2005). Current trophic state index (TSI) scores confirm that the BMPs have positively affected water quality in Lake Harriet.

In 2010, the MPRB and the City of Minneapolis received a Clean Water Partnership Grant to complete a diagnostic study of Lake Harriet to update and intensify existing studies at the lake and provide planning toward implementing a second-phase of improvements for water quality.

LAKE LEVEL

The lake level for Lake Harriet is recorded weekly and is shown in Figure 8-3. Following two years with heavy spring rains and high lake levels, the 2015 levels were lower and comparable to a normal year.

The ordinary high water level (OHW) determined by the MDNR for Lake Harriet is 846.82 ft msl. The designated OHW is the highest regularly sustained water level that has made a physical imprint on the land, marked by either a transition in vegetation or a physical characteristic.

See Section 18 for a comparison between other MPRB lake levels.

2015 Water Resources Report – Minneapolis Park & Recreation Board Page 8-3

Figure 8-3. Lake levels for Lake Harriet from 1971 to the present. Horizontal line represents the Lake Harriet ordinary high water elevation (846.82 ft msl).

WATER QUALITY TRENDS – TROPHIC STATE INDEX (TSI)

The TSI scores for Lake Harriet are improving as shown by the linear regression in Figure 8-4. A detailed explanation of TSI can be found in Section 1.

Figure 8-4. Lake Harriet TSI scores and linear regression from 1991-2015.

Lake Harriet’s 2015 TSI score was 47, which classifies the lake as mesotrophic with moderately clear water and some algae. There is no significant trend in TSI scores from 1991-2015 (p > 0.05) and scores have stayed between 45 and 50 for the last ten years. The lake remains in the top 25% of TSI scores in this ecoregion (based on calculations from the Minnesota Pollution Control Agency, using the Minnesota Lake Water Quality Data Base Summary, 2004).

2015 Water Resources Report – Minneapolis Park & Recreation Board Page 8-4

BOX AND WHISKER PLOTS

The box and whisker plots in Figure 8-5 show the data distribution for Secchi, chlorophyll-a, and total phosphorus sampling for the past ten years. MPCA deep lake standards are indicated by a horizontal line across the box plot graphs. A further detailed explanation of box and whisker plots can be found in Section 1. Appendix A contains box plots of data for all of the years of record.

There was little variation in water clarity in Lake Harriet during 2015 and was similar to 2014. Both chlorophyll-a and total phosphorus were similar to previous years, with higher phosphorus levels early in the season. Harriet met the MPCA eutrophication standard for Secchi depth, chlorophyll-a, and total phosphorus in 2015.

Figure 8-5. Lake Harriet box and whisker plots of TSI data for the past 10 years. Horizontal lines represent MPCA eutrophication standard for deep lakes. See Appendix A for the entire period of record.

2015 Water Resources Report – Minneapolis Park & Recreation Board Page 8-5

Figure 8-5 ctd. Lake Harriet box and whisker plots of TSI data for the past 10 years. Horizontal lines represent MPCA eutrophication standard for deep lakes. See Appendix A for the entire period of record.

BEACH MONITORING

Escherichia coli (E. coli) levels were sampled at two different locations on Lake Harriet: Harriet Main Beach and Harriet Southeast Beach. As shown in Table 8-2 and Figure 8-6, E. coli counts were low for the most of beach season. Neither Lake Harriet beach closed in 2015 due to high bacteria levels.

Table 8-2. Summary of E. coli results (per 100 mL) for Lake Harriet beaches in 2015.

Statistical Calculations Harriet Main Harriet SE

Number of Samples 13 13 Minimum 4 1 Maximum 129 243 Median 12 36 Mean 21 62 Geometric Mean 13 26 Max 30-Day Geo Mean 22 85 Standard Deviation 33 70

Figure 8-6 illustrates the box and whisker plots of E. coli sampling results (MPN per 100 mL) for Lake Harriet beaches for the past ten years. Results from 2015 at Harriet Southeast Beach were slightly higher than recent years, while Harriet Main Beach were similar to previous years. The samples with higher bacteria at Harriet Southeast beach were taken after weekend rain events and noticeable erosion of the beach on Monday morning, when the samples were taken. The dashed red line represents the E. coli standard for the 30-day geometric mean (126 MPN/100mL), while the solid red line represents the single-sample maximum standard (1260 MPN/100mL). Further details on MPRB beach monitoring can be found in Section 19.

2015 Water Resources Report – Minneapolis Park & Recreation Board Page 8-6

Figure 8-6. Box and whisker plots of E. coli results (per 100 mL) for Lake Harriet beaches, 2006-2015. The dashed horizontal line represents the E. coli standard for the 30- day geometric mean (126 MPN/100mL) and the solid horizontal line represents the single-sample maximum standard (1260 MPN/100mL). Note the log scale on the Y-axis. From 2006-2009 E. coli concentrations were determined as colony forming units (CFU/100ml).

2015 Water Resources Report – Minneapolis Park & Recreation Board Page 8-7

LAKE AESTHETIC AND USER RECREATION INDEX (LAURI)

Figure 8-7 shows the 2015 LAURI for Lake Harriet. Lake Harriet ranked “excellent” in aesthetics, habitat quality, public health, and recreational access. The lake scored “good” in water clarity largely due to slightly elevated algal growth in June. Details on the LAURI can be found in Section 1.

LAKE HARRIET 2015 POOR GOOD EXCELLENT Aesthetics

Water Clarity

Public Health

Habitat Quality

Rec. Access

Figure 8-7. The 2015 LAURI for Lake Harriet.

2015 Water Resources Report – Minneapolis Park & Recreation Board Page 8-8 WINTER ICE COVER

Ice went out on Lake Harriet on April 2, 2015 which, was five days earlier than average. Ice did not completely cover Lake Harriet for the season again until January 4, 2016, which was 22 days later than the average ice-on date. See Section 1 for details on winter ice cover records and Section 18 for a comparison with other lakes.

EXOTIC AQUATIC PLANT MANAGEMENT

The MDNR requires a permit to remove or control Eurasian watermilfoil. These permits limit the area milfoil can be harvested in order to protect fish habitat. The permits issued to the MPRB allowed for harvesting primarily in swimming areas, boat launches and in shallow areas where recreational access was necessary. The permitted area for Eurasian water milfoil harvest on Lake Harriet was 40 acres, which is 45% of the littoral zone of the lake (area shallower than 15 feet). More information on aquatic plants can be found in Section 1 and Section 20.

PHYTOPLANKTON AND ZOOPLANKTON

Phytoplankton and zooplankton are the microscopic plants and animals that form the foundation of the food web in lakes. Figure 8-8 shows the Secchi transparency, chlorophyll-a concentrations, and relative abundance of phytoplankton division during the 2015 sampling season.

Secchi depth was greater than 2 m for the entire open water season in 2015 at Lake Harriet (Figure 8-8a). Chlorophyll-a concentrations were low (< 7 µg L-1) for much of the season with the exception of early June when chlorophyll-a levels reached 15 µg L-1 (Figure 8-8b). The clearest water of the year occurred in May with Secchi depths greater than 5 m and low chlorophyll-a levels (< 2 µg L-1). Blue green algae (Cyanophyta), cryptomonads (Cryptophyta), and green algae (Chlorophyta) characterized the majority of the phytoplankton community in the early season. Blue green algae comprised much of the phytoplankton community for the remainder of the season with Secchi depths ranging from 2-3 m. In eutrophic lakes, blue-green algae are often indicators of poor water quality; however, blue-green algae can dominate even in lakes with good water quality due to their ability to scavenge nutrients and out-compete other groups. Cryptomonads (Cryptophyta) also bloomed early and remained a minor part of the phytoplankton community through October. Cryptomonads are relatively small (3-50 µm long) members of the phytoplankton community and are common in cold waters. Diatoms (Bacillariophyta), haptophytes, Dinoflagellates (Pyrrhophyta), and chrysophytes were present at various times throughout the season as well (Figure 8-8c).

Zooplankton abundance in Lake Harriet during the 2015 sampling season is shown in Figure 8-9. Nauplii and juvenile zooplankton were present in all the samples, but were at the highest density in the spring and early summer. Rotifers were present in high numbers throughout the season as well. Cladocerans and cyclopoids were present throughout the year, with the highest concentrations occurring in the fall. Calanoids and protozoa were only present in low numbers.

2015 Water Resources Report – Minneapolis Park & Recreation Board Page 8-9

Figure 8-8. Secchi transparency (a), chlorophyll-a concentration (b), and relative abundance of phytoplankton (c) during the 2015 Lake Harriet sampling season. Note that the Secchi depth axis is reversed.

2015 Water Resources Report – Minneapolis Park & Recreation Board Page 8-10

Figure 8-9. Zooplankton distribution in Lake Harriet for 2015.

FISH STOCKING

Additional information and a definition of fry, fingerling, yearling and adult size fish can be found in Section 1.

Lake Harriet was stocked by MDNR in: 1998 with 250 fingerling Muskellunge, 1,365 fingerling Walleye. 1999 with 824 fingerling Walleye, 50 yearling Walleye. 2000 with 175 fingerling Muskellunge, 142 adult Walleye, 499 adult Walleye. 2001 with 2,273 fingerling Walleye. 2002 with 175 fingerling Muskellunge, 312 fingerling Walleye, 698 yearling Walleye. 2003 with 554 fingerling Walleye, 33 yearling Walleye. 2004 with 175 fingerling Muskellunge, 3,447 fingerling Walleye. 2005 with 140 yearling Walleye. 2006 with 175 fingerling Muskellunge, 1,919 fingerling Walleye, 33 adult Walleye. 2007 with 136 adult Walleye, 50 fingerling Walleye, and 428 yearling Walleye.

2015 Water Resources Report – Minneapolis Park & Recreation Board Page 8-11 2008 with 117 adult Walleye, 3,234 fingerling Walleye, and 175 fingerling Muskellunge. 2009 with 110 yearling Walleye, and 2,482 fingerling Walleye. 2010 with 179 fingerling Muskellunge, and 2862 fingerling Walleye. 2011 with 3,244 fingerling Walleye. 2012 with 175 fingerling Muskellunge, and 2,520 yearling Walleye. 2013 with 2,890 fingerling Walleye. 2014 with 2,545 fingerling Walleye. 2015 with 165 yearling Walleye.

2015 Water Resources Report – Minneapolis Park & Recreation Board Page 8-12 9. LAKE HIAWATHA

HISTORY

Lake Hiawatha was acquired by the Minneapolis Park & Recreation Board (MPRB) in 1923 at a cost of $555,000. At that time the lake was a shallow wetland named Rice Lake for the stands of wild rice that grew in its shallow waters. Lake Hiawatha was renamed after Henry Wadsworth Longfellow’s poem “Song of Hiawatha” in 1925. Major changes were made to the shape and depth of Lake Hiawatha in the early part of the 20th century in an attempt to improve health and to make it more desirable to build and live near the lake. Beginning in 1929, over 1.25 million cubic yards of material were dredged and relocated to construct Hiawatha Golf Course. Today Lake Hiawatha is part of the Lake Nokomis–Lake Hiawatha Regional Park.

Figure 9-1. Great blue heron taking flight at Lake Hiawatha in 2015.

Figure 9-2 shows the bathymetric map of Lake Hiawatha. Lake Hiawatha has an extremely large watershed due its connection with Minnehaha Creek. The watershed of the lake includes 115,840 acres and the large volume of runoff associated with this area (~97% of the water and ~88% of the phosphorus input to the lake) reduces the residence time of the water in the lake to an average of 11 days or less. Flushing time in Lake Hiawatha is short compared to most other lakes in Minneapolis that have residence times up to four years (Table 18-1). The limited amount of time the water spends in the lake affects the biology of the system. The most obvious effect is a generally less than expected level of algae in the water based on the amount of phosphorus present. The converse of this occurs during seasons with low creek flow (for example 2002, 2007 and 2009) which increased the residence time in the lake and allows excess algae to build up. Table 9-1 shows the morphometric data for Lake Hiawatha.

2015 Water Resources Report – Minneapolis Park & Recreation Board Page 9-1 Flow contributed from the creek and from storm sewer connections have other physical repercussions for Lake Hiawatha. A delta has formed at the point where Minnehaha Creek meets the lake. The water level in Lake Hiawatha varies widely due to fluctuations in the flow of Minnehaha Creek. Additionally, the creek and stormwater inflow can have a destabilizing effect on the thermal stratification of the lake during the summer months.

Figure 9-2. Bathymetric map of Lake Hiawatha based on MCWD data.

Table 9-1. Lake Hiawatha morphometric data.

Surface Watershed: Mean Max Littoral Volume Watershed Residence Area Lake Area Depth (m) Depth (m) Area* (m3) Area (acres) Time (years) (acres) (ratio) 54 4.1 7.0 49% 8.95x105 115,840 2145 0.03 *Littoral area defined as less than 15 feet deep.

2015 Water Resources Report – Minneapolis Park & Recreation Board Page 9-2 LAKE LEVEL

Lake levels for Lake Hiawatha are recorded weekly during the open water season. The lake levels for Lake Hiawatha from 1996 to the present are shown in Figure 9-3. Up to four feet of water level bounce can be seen in Lake Hiawatha due to the influence of Minnehaha Creek and the dam at Gray’s Bay in Lake Minnetonka. Following heavy rains and record high lake levels in Lake Hiawatha during the summer of 2014, lake levels were generally lower in 2015. However, there were two peaks in July and November following above average precipitation in those months. The OHW as determined by the MDNR is 812.8 ft msl.

Figure 9-3. Lake levels for Lake Hiawatha 1995-2015. Horizontal line represents the Lake Hiawatha ordinary high water elevation (812.8 ft msl).

WATER QUALITY TRENDS – TROPHIC STATE INDEX (TSI)

Figure 9-4 shows the Lake Hiawatha linear regression of TSI scores over time. A detailed explanation of TSI can be found in Section 1. The TSI score of Lake Hiawatha mainly reflects the water it receives from Minnehaha Creek. Abnormally high TSI scores seen in the years 2000, 2007, 2009, and 2012 coincide with drought years where Minnehaha Creek was dry for at least a portion of the summer. With all years taken into consideration, Lake Hiawatha has no significant trend in TSI score from 1992 to 2015 (p > 0.05) shown in Figure 9-4. The 2015 TSI score for Lake Hiawatha was 56, which is slightly lower than normal for the lake. Currently Lake Hiawatha has a TSI score that is average for lakes in the Central Hardwood Forest ecoregion (MPCA, 2004).

2015 Water Resources Report – Minneapolis Park & Recreation Board Page 9-3

Figure 9-4. Lake Hiawatha TSI scores and liner regression from 1992-2015.

BOX AND WHISKER PLOTS

The box and whisker plots in Figure 9-5 show the variation between years for the Secchi, chlorophyll-a, and total phosphorus data for the past ten years. Lake Hiawatha site specific standards are indicated by a horizontal line on the box plot graphs. The US EPA approved a new 50 µg L-1 TP standard for Lake Hiawatha in 2013 (MPCA, 2013). A detailed explanation of box and whisker plots can be found in Section 1. Data collected since 1992 in box and whisker format is available Appendix A. Long-term lake monitoring is necessary to evaluate the seasonal and year-to-year variations seen in each lake and predict trends.

In most years, the Lake Hiawatha system is similar due to short residence times and the strong influence of Minnehaha Creek. In 2015, Hiawatha met the site specific standards set by the MPCA for both Secchi depth and chlorophyll-a, but did not meet the total phosphorus standard. Water transparency in 2015 was similar to the previous five years and one of the clearest on record. Both chlorophyll-a and total phosphorus levels were higher than 2014, but were similar to historic concentrations. This could be explained by the abnormally high precipitation in 2014. Continued monitoring will help evaluate effects of climate variability on the water quality in Lake Hiawatha.

2015 Water Resources Report – Minneapolis Park & Recreation Board Page 9-4

Figure 9-5. Ten years of box and whisker plots of Lake Hiawatha TSI data. Horizontal lines represent Lake Hiawatha site specific eutrophication standards. See Appendix A for the entire period of record.

BEACH MONITORING

The public beach at Lake Hiawatha was officially closed from 2004 to 2006 because of budgetary constraints and the history of E. coli bacteria issues at the beach. Due to concern about bacteria levels, monitoring continued while the beach was closed. Because of the beach’s popularity with the public and its continued heavy use, the MPRB re-opened the beach in 2007.

2015 Water Resources Report – Minneapolis Park & Recreation Board Page 9-5

Table 9-2. Summary of 2015 E. coli (MPN per 100 mL) results for Lake Hiawatha.

Statistical Calculations Hiawatha

Number of Samples 13 Minimum 12 Maximum 2420 Median 355 Mean 728 Geometric Mean 280 Max 30-Day Geo Mean 506 Standard Deviation 882

Table 9-2 shows the basic statistics on the 2015 bacteria sampling at Lake Hiawatha. The 30-day geometric mean standard of 126 MPN/100 mL was exceed in early July of 2015 and remained over the standard for the rest of the swimming season (Figure 9-6). Further details on MPRB beach monitoring can be found in Section 19.

Figure 9-6. 2015 E. coli concentrations at Hiawatha Beach. Blue line is the running 30-day geometric means and the horizontal red line represents the 30-day geometric mean standard of 126 colonies per 100 mL.

2015 Water Resources Report – Minneapolis Park & Recreation Board Page 9-6

Figure 9-7. Box and whisker plot of E. coli results (per 100 mL) for the Lake Hiawatha site, 2006 to 2015. Note the log scale on the Y-axis. The dashed horizontal line represents the E. coli standard for the 30-day geometric mean (126 MPN/100mL) and the solid horizontal line represents the single-sample maximum standard (1260 MPN/100mL). From 2006-2009 E. coli concentrations were determined as colony forming units (CFU/100ml).

Figure 9-7 shows box and whisker plots of E. coli sampling results (per 100 mL) for the past ten years. The 2015 season had high E. coli counts compared to previous years. The highest bacteria levels occurred in July following heavy rains and high flows from Minnehaha Creek. The range of results at Lake Hiawatha is larger than at the other lakes in Minneapolis due to the large influence Minnehaha Creek has on the lake’s water quality.

LAKE AESTHETIC AND USER RECREATION INDEX (LAURI)

The LAURI for Lake Hiawatha is shown in Figure 9-8. In 2015, Lake Hiawatha scored “excellent” in aesthetics and water clarity. The lake scored “good” in habitat quality and recreational access and “poor” on public health. Lake Hiawatha scored “excellent” in aesthetics due to low water odor and light brown/green water color; however, it collects trash flowing down Minnehaha Creek, especially after large rainstorms. The trash gets deposited along the still shoreline of the lake where it usually remains for the rest of the summer. Details on the LAURI index can be found in Section 1.

2015 Water Resources Report – Minneapolis Park & Recreation Board Page 9-7

Figure 9-8. The 2015 LAURI for Lake Hiawatha.

WINTER ICE COVER

Ice came off Lake Hiawatha on March 29, 2015, six days earlier than average. Ice returned to the lake for the winter on December 28, 2015, 25 days later than the averaage ice-on date. See Section 1 for details on winter ice cover records and Section 18 for a comparison with other lakes.

2015 Water Resources Report – Minneapolis Park & Recreation Board Page 9-8 PHYTOPLANKTON AND ZOOPLANKTON

Phytoplankton and zooplankton are the microscopic plant and animal life that form the foundation of the food web. The Secchi transparency, chlorophyll-a concentrations, and relative abundance of phytoplankton division during the 2015 sampling season composition is shown in Figure 9-9. Secchi depth fluctuated throughout the year and decreased from 2.8 meters in May and early June to less than 1 meter in the fall (Figure 9-9a). Chlorophyll-a concentrations were the highest (28 µg L-1) under the ice in early March and fluctuated between 4-17 µg L-1 for the remainder of the year (Figure 9-9b). Chrysophytes and cryptomonads dominated the phytoplankton community in the winter sample when chlorophyll-a values were the highest. Both cryptomonads and chrysophytes contain chlorophyll-a for photosynthesis but some species are also able to utilize organic matter to acquire carbon. Spring was characterized by diatoms (Bacillariophyta) and cryptomonads. Blue green algae (Cyanophyta) and green algae (Chlorophyta) became more abundant in the summer months while cryptomonads and diatoms were still present. Blue green algae typically represent the majority of the phytoplankton community in Lake Hiawatha. The fall phytoplankton community was comprised almost entirely of diatoms. Dinoflagellates (Pyrrhophyta), haptophytes, and euglenoids were present in low abundances during the season (Figure 9-9c).

2015 Water Resources Report – Minneapolis Park & Recreation Board Page 9-9

Figure 9-9. Secchi transparency (a), chlorophyll-a concentration (b), and relative abundance of phytoplankton (c) during the 2015 Lake Hiawatha sampling season. Note that the Secchi depth axis is reversed.

Figure 9-10 shows the zooplankton distribution in Lake Hiawatha during the 2015 sampling season. Cladocerans, rotifers and juveniles were the dominating zooplankton groups present throughout the sampling season. Calanoids, cyclopoids, and protozoa were only present in low numbers throughout the season. Like most of the Minneapolis lakes, juvenile zooplankton were at their highest concentrations in early spring.

2015 Water Resources Report – Minneapolis Park & Recreation Board Page 9-10

Figure 9-10. Lake Hiawatha zooplankton distribution during the 2015 sampling season.

EVENTS REPORT

On July 28 2010, zebra mussels (Dreissena polymorpha) were confirmed as present in Lake Minnetonka and at the headwaters of Minnehaha Creek by MDNR ecologists. The MDNR declared Lake Minnetonka, Minnehaha Creek and all public waters with creek connections to be infested with zebra mussels, including Lake Hiawatha.

In response, MPRB has been installing zebra mussel sampling plates in five lakes since 2010. In 2011, Water Resources staff began using a separate set of equipment only to be used on infested lakes as a precaution to not spread zebra mussels. Since 2012, the MPRB has operated an Aquatic Invasive Species (AIS) Inspection Program at boat launches on Lake Calhoun, Lake Harriet, and Lake Nokomis to prevent the spread of zebra mussels.

Zebra mussels had been expected to arrive in Lake Hiawatha within a few years after their discovery in Lake Minnetonka, due to its direct connection with Minnehaha Creek. In August 2013, Water Resources staff discovered and the Minnesota DNR confirmed the finding of zebra mussels on a sampling plate in Lake Hiawatha. Since, staff has continued to monitor the sampling plate and conduct annual shoreline survey to determine the extent of infestation. Figure 9-11 shows the results of the annual rapid shoreline survey from 2013-2015. Zebra mussels have been found in low densities around much of the lake, but the population of the invasive mussel in the lake appears to be low. Future surveys and lake monitoring will indicate whether zebra mussels are altering the ecology of the lake.

2015 Water Resources Report – Minneapolis Park & Recreation Board Page 9-11

Figure 9-11. Results of zebra mussel shoreline surveys from 2013-2015.

2015 Water Resources Report – Minneapolis Park & Recreation Board Page 9-12 10. LAKE OF THE ISLES

HISTORY

Lake of the Isles was named for the four islands that were present in the lake prior to alteration of the park. The original park property consisted of 100 acres of water, 67 acres of wetland, and 33 acres of land. The park was acquired by the Minneapolis Park and Recreation Board in 1886 through purchase, donation, and condemnation. One of the islands had already been eliminated in 1884 by the Chicago Milwaukee and Saint Paul Railway when tracks were laid on fill between Lake Calhoun and Isles. Half a million cubic yards of material were dredged between 1889 and 1911 eliminating a second island and increasing the lake area to 120 acres. The lake was further modified by filling 80 acres of marsh to create parkland, to deepen the North Arm to a uniform depth, and to replace the marshy east side of the lake with an upland shoreline. The connection of Isles to Calhoun was completed in 1911 and was celebrated by citywide festivities. Lake of the Isles is part of the Chain of Lakes Regional Park which receives nearly 5.5 million visitors year and the most visited park in Minnesota (Metropolitan Council, 2015).

The lake was part of the Clean Water Partnership project for the Chain of Lakes and was the focus of multiple restoration activities including grit chambers (1994, 1997, 1999) for stormwater sediment removal, constructed wetland detention ponds for further treatment of incoming stormwater, and a whole lake alum treatment (1997) to limit the internal loading of phosphorus.

Lake of the Isles is a shallow lake with dense stands of macrophytes in shallow areas. The lake is polymictic as it becomes thermally stratified and periodically mixes due to wind throughout the summer. Figure 10-1 shows Lake of the Isles in fall. Table 10-1 shows the Lake of the Isles morphometric data. Figure 10-2 shows the Lake of the Isles bathymetry.

Figure 10-1. Lake of the Isles in 2015.

2015 Water Resources Report – Minneapolis Park & Recreation Board Page 10-1

Table 10-1. Lake of the Isles morphometric data.

Surface Mean Watershed: Residence Max Littoral Volume Watershed Area Depth Lake Area Time Depth (m) Area* (m3) Area (acres) (acres) (m) (ratio) (years) 103 2.7 9.4 89% 1.11x106 735 7.1 0.6 *Littoral area defined as less than 15 feet deep.

Lake of the Isles Bathymetry

S

H D

E N O S R E

A I O E D

S

U U M

A W

E P Q

O 21ST

N N

T M

H E

O N T A

T S K 21 E J N W

R 1 T E 0 22ND O

V

I N N

L

N

O

E 22ND P N

0 S A 1 A D I T M

R D O E L

H H O T S 24TH 24TH B

M

L

U

L

H

E

S 0

S

U 25 BURNHAM R T S H H E E K R A ID L A N

T 26 H TH N O O 18 M W T ID P A U E L S 10 C S U T E KENILWORTH L 0 A 10

K

E 2

0 S

O 5 5 3 0 5 E 1

F 2 0 2 L

S T I 6 H E DEAN G E H N I T I

S V 2 F 7T L R H O I E

S E N 1 K I 15 0 P LA E 7 25 S T N A 1 S N N 3 0 2 A E M 20 O 15 E H T O 5 28T P H H U T 28TH

S

E

MIDTO M WN GREEN A WAY W J 1:8,800

00.05 0.1 0.2 0.3 0.4 0.5 Miles Water Bathymetry of Lake of the Isles. Fieldwork by MDNR 1958. Depth Contours Contours provided by MDNR, digitized by MPRB. Streets Additional data provided by the City of Minneapolis.

Figure 10-2. Bathymetric map of Lake of the Isles.

2015 Water Resources Report – Minneapolis Park & Recreation Board Page 10-2 LAKE LEVEL

The ordinary high water level (OHW) designated by the MDNR for Lake of the Isles is 853 ft msl. The designated OHW is an estimate of the highest regularly sustained water level that has made a physical imprint on the land. This mark may be a transition in vegetation or a physical characteristic. For additional lake level information see Lake Calhoun in Section 4.

WATER QUALITY TRENDS – TROPHIC STATE INDEX (TSI)

Figure 10-3 shows the Lake of the Isles linear regression of TSI scores from 1991 to the present. The Lake of the Isles 2014 TSI score is 54, average for this ecoregion (based on calculations from the Minnesota Pollution Control Agency using the Minnesota Lake Water Quality Data Base Summary, 2004). There has been no significant trend in TSI score since 1991 (p > 0.05). The alum treatment in 1997 coincided with the lowest/best TSI score for Lake of the Isles, but did not result in a long term decrease in TSI scores. A detailed explanation of TSI can be found in Section 1.

Figure 10-3. Lake of the Isles TSI scores and linear regression. The blue square highlights the 1997 alum treatment.

BOX AND WHISKER PLOTS

The box and whisker plots in Figure 10-4 show the data distribution for the Secchi, chlorophyll-a, and total phosphorus for the past ten years. MPCA standards are indicated by a horizontal line on the plots. A detailed explanation of box and whisker plots can be found in Section 1 and all available data in box and whisker format can be found in Appendix A.

All data shown in Figure 10-4 were measured after Clean Water Partnership project improvements installed between 1994 and 1997. Water transparency in 2015 ranged from less than 0.5 meters to greater than 4 meters throughout the year; however, the summer average water clarity met state eutrophication standards. Similarly, average chlorophyll-a and total phosphorus levels met state standards and were comparable to concentrations in the late 2000s. Total phosphorus levels appear to vary year to year and apart from the high samples in the winter and early spring, 2015 phosphorus levels were on the low end compared to the past 10 years.

2015 Water Resources Report – Minneapolis Park & Recreation Board Page 10-3

Figure 10-4. Lake of the Isles box and whisker plots of TSI data from 2006-2015. Horizontal lines represent MPCA eutrophication standard for shallow lakes. See Appendix A for the entire period of record.

2015 Water Resources Report – Minneapolis Park & Recreation Board Page 10-4 LAKE AESTHETIC AND USER RECREATION INDEX (LAURI)

The LAURI for Lake of the Isles is shown in Figure 10-5. In 2015, Lake of the Isles scored “excellent” in aesthetics, water clarity, habitat quality, and recreational access. Since Lake of the Isles does not have a swimming beach, a score was not calculated for public health. For more details on LAURI see Section 1.

Figure 10-5. The LAURI for Lake of the Isles in 2015.

2015 Water Resources Report – Minneapolis Park & Recreation Board Page 10-5 WINTER ICE COVER

Ice came off Lake of the Isles on March 30, 2015, 6 days earlier than average. Ice fully covered the lake on December 21, 2015, which was 20 days later than average for Lake of the Isles. See Section 1 for details on winter ice cover records and Section 18 for a comparison with other lakes.

EXOTIC AQUATIC PLANT MANAGEMENT

The MDNR requires a permit to remove or control Eurasian water milfoil. In order to protect fish habitat, the MDNR permits limit the area from which milfoil can be harvested. The permits issued to the MPRB allowed for harvesting primarily in swimming areas, boat launches, and in shallow areas where recreational access was necessary. The area permitted for milfoil harvesting in Lake of the Isles in 2015 was 38 acres which is just over 40% of the littoral zone (area shallower than 15 feet). See Section 1 and Section 20 for details on aquatic plants.

PHYTOPLANKTON AND ZOOPLANKTON

Phytoplankton and zooplankton are the microscopic plant and animal life that form the foundation of the food web in lakes. Figure 10-6 shows the Secchi transparency, chlorophyll-a concentrations, and relative abundance of phytoplankton division during the 2015 sampling season. Figure 10-7 shows the abundance of zooplankton groups in 2015. The winter sample was dominated by haptophytes and cryptomonads. Secchi depth was around 1 meter in April, but increased to greater than 4 meters in early June. Chlorophyll-a levels remained low (< 4 µg L-1) during that time and was comprised mainly of diatoms (Bacillariophyta), chrysophytes, cryptomonads, and dinoflaggelates (Pyrrhophyta). Water transparency decreased the rest of the summer as chlorophyll-a levels increased led by the emergence of blue green algae (Cyanophyta) to a high level of 52 µg L-1 in early August. Secchi depth increased and chlorophyll-a concentrations returned to low levels in the fall with an increase in chrysophytes again in October.

The distribution of zooplankton for Lake of the Isles is shown in Figure 10-7. There were low numbers of zooplankton in April. Rotifers emerged in high numbers in May and slowly decreased the rest of the year. Nauplii and juvenile zooplankton were also present in May and were at their highest density in July. Cladocerans, large zooplankton that graze on algae, were present in most samples. Similar to other lakes, cyclopoids and calanoids were present in low levels in most samples.

2015 Water Resources Report – Minneapolis Park & Recreation Board Page 10-6

Figure 10-6. Secchi transparency (a), chlorophyll-a concentration (b), and relative abundance of phytoplankton (c) during the 2015 Lake of the Isles sampling season. Note that the Secchi depth axis is reversed.

2015 Water Resources Report – Minneapolis Park & Recreation Board Page 10-7

Figure 10-7. Lake of the Isles 2015 zooplankton distribution.

FISH STOCKING

Additional information and a definition of fry, fingerling, yearling, and adult fish can be found in Section 1.

Lake of the Isles was stocked by MDNR in: 2000 with 300 fingerling Tiger Muskellunge. 2004 with 300 fingerling Tiger Muskellunge. 2007 with 180 fingerling Tiger Muskellunge.

2015 Water Resources Report – Minneapolis Park & Recreation Board Page 10-8 11. LORING POND

HISTORY

Loring Park was acquired in 1883 as the “Central Park” of Minneapolis. Loring Pond was named in 1890 in honor of Charles M. Loring the first president of the Board of Park Commissioners and is known as the “Father of the Minneapolis Park System.”

The pond’s current configuration was created by connecting two small bodies of water: Jewett Lake and Johnson’s Pond. The smaller north basin of the pond was originally a wetland. In the winter of 1883-1884, peat was sawn out of the frozen ground in order to create a basin that would hold open water. Stormwater diversion has reduced the watershed of Loring Pond to the surrounding 24.1 acres of parkland and has left the lake with a negative water balance; therefore, a groundwater augmentation well is used to maintain water levels.

Figure 11-1 is a photograph of Loring Pond and Figure 11-2 is a map of the pond showing estimated bathymetry. Table 11-1 shows the morphometric data for Loring Pond.

Figure 11-1. Loring cattail removal in the fall 2014.

2015 Water Resources Report – Minneapolis Park & Recreation Board Page 11-1

Loring Pond Bathymetry

0

15

10 5

E V

RO G 15 TH K A O 1:2,000

050 100 200 300 400 500 Feet Water Depth Contours Bathymetry of Loring Pond. Streets Contours estimated by MPRB, unknown source. Paths Additional data provided by the City of Minneapolis.

Figure 11-2. Map of Loring Pond showing approximate bathymetry contours.

Table 11-1. Loring Pond morphometric data.

Surface Area Mean Depth Maximum Volume Watershed Area Watershed: Lake (acres) (m) Depth (m) (m3) (acres) Area (ratio) 8 1.5 5.3 4.88x104 24.1 3.0

2015 Water Resources Report – Minneapolis Park & Recreation Board Page 11-2

Several attempts were made in the 1970s to improve water quality in Loring Pond. An Olszewski tube was installed in an attempt to drain high-nutrient hypolimnetic water from the lake. The tube never functioned properly and was abandoned. The pipe was capped in 2014 in an effort to limit water losses in the pond. Dredging of the north arm from 1976 to1977 also did not improve the water quality of the lake. Augmentation of the lake level with groundwater appears to have had a positive effect on water quality and continues today.

Further lake restoration and park improvement projects were initiated in 1997. The lake bottom was sealed, lined, and vented. An aerator was installed to help prevent oxygen depletion during the summer months. Multiple vegetation restoration projects were completed throughout the park. A fishing pier, bike and pedestrian trails, and horseshoe courts were also installed to increase park recreational opportunities. In 1999, the shoreline was planted with native vegetation in cooperation with the Minnesota Department of Natural Resources (MDNR) and the Friends of Loring Park. The native shoreline restoration provided a buffer strip for waterfowl management, protection against shoreline erosion, pollutant filtration, and improved lake aesthetics.

In 2007, the north basin was dredged again to remove accumulated sediment and restore original depths in the channel between the northern and southern basins. In order to accomplish this, the northern basin was dewatered and the water level in the southern basin was lowered. The project had the unintended consequence of stimulating cattail growth that led to a multi-year cattail removal project that MPRB began in 2013. See Water Quality Projects for more details on the work associated with the latest cattail removal and vegetation restoration project.

LAKE LEVEL

Lake levels for Loring Pond are recorded weekly during ice free conditions and are shown in Figure 11-3 for 1994-2015. Loring Pond lake levels are influenced by an augmentation well that is used to pump groundwater into the lake periodically throughout the year to maintain a consistent level. As the water level was often below the bottom of the lake gauge on the outlet structure, a new auxiliary gauge was installed in 2013.

Dewatering for the North Bay dredging project lowered water levels in Loring significantly in 2007. Stormsewer backflow entered Loring several times in 2010 and 2011 during high-intensity rain events and the largest of these events can be seen as peaks in the level graph. Water pressure from stormsewer backflow caused the Loring Pond outlet to deteriorate. In 2011, MPRB staff repaired the cement at the base of the outlet and re-installed the outlet board. Staff were able to raise the level of the lake using groundwater, but pumping could not overcome the amount of water lost in the late summer drought. High water levels in 2012 were due to a malfunction in the groundwater pump. Water levels were manipulated and drawn down throughout the summer and then raised to the top of the outlet wall as part of a cattail removal in 2014. Water levels were kept near the top of the outlet in 2015 as well. See Water Quality Projects for more details.

The ordinary high water level (OHW) designated by the MDNR for Loring Pond is 818.0 ft msl. The designated OHW is an estimate of the highest regularly sustained water level that has made a physical imprint on the land. See Section 18 for a comparison between other MPRB lake levels.

2015 Water Resources Report – Minneapolis Park & Recreation Board Page 11-3

Figure 11-3. Lake levels for Loring Pond from 1994 – 2015. Water levels frequently dropped below the gage in the 2000s and water levels couldn’t be accurately measured during that time. An auxiliary gage installed in 2013 is able be read at lower lake levels. Horizontal line represents Loring Pond OHW (818.0 ft msl).

AUGMENTATION WELLS

An augmentation well is used to maintain the water levels at Loring Pond. The Minnesota Department of Natural Resources (MDNR) issues the permits and determines pumping limits for augmentation wells. The MPRB staff records groundwater usage monthly. Table 11-2 shows annual usage for the past five years. In 2015, all 12 million gallons of the annual groundwater permit was used and an additional 6,732,120 million gallons out of a temporary permit issued for the cattail removal project was pumped into Loring Pond.

Table 11-2. Loring Pond annual pumping volume in gallons.

2011 2012 2013 2014 2015 Total (gal) Total (gal) Total (gal) Total (gal) Total (gal) 8,475,000 11,572,500 1,378,500 6,871,020 18,732,120

2015 Water Resources Report – Minneapolis Park & Recreation Board Page 11-4 WATER QUALITY TRENDS – TROPHIC STATE INDEX (TSI)

The 2015 TSI score for Loring Pond was 57, the lowest score since 1992 when data collection began. Loring Pond has a TSI score that falls near the 50th percentile category for lakes in the Northern Central Hardwood Forest ecoregion (MPCA, 2004). Figure 11-4 shows the TSI data for Loring Pond along with a linear regression. A detailed explanation of TSI can be found in Section 1.

There is no significant trend in TSI from 1992-2015 in Loring Pond (p < 0.05). Caution should be used when viewing the Loring Pond data in total since dredging projects that disturbed all or a large portion of the lake occurred in 1997-1998 and during the summer of 2007. Additionally, water levels have been manipulated from 2013-2015 and a large amount of groundwater was pumped into the lake in the summer of 2015.

Figure 11-4. Loring Pond TSI data and linear regression from 1990 to 2015. The lake was significantly manipulated during 1997-1998 and the summer of 2007. Due to these disturbances, data should be viewed with caution.

BOX AND WHISKER PLOTS

The box and whisker plots in Figure 11-5 show the distribution of data for the Secchi, chlorophyll-a, and total phosphorus measurements for the past ten years. MPCA shallow lake standards are shown as a horizontal line across the box plots. A detailed explanation of box and whisker plots can be found in Section 1. Data presented in box and whisker plot format for the entire period of record can be found Appendix A.

The 303(d) assessment for impaired waters is limited to lakes of ten acres or greater (MPCA, 2014); therefore, Loring Pond is too small (8 acres) to be listed on MPCA’s impaired waters list. However, it is still useful to compare Loring’s data to the shallow lake standards to determine lake water quality. Secchi transparency was greater than 1 meter all year long and is significantly different than pre-2014 transparencies. Chlorophyll-a levels were similar to 2014 and significantly lower than previous years. However, total phosphorus concentrations were still high in 2015 with the highest value in the winter sample.

2015 Water Resources Report – Minneapolis Park & Recreation Board Page 11-5

Figure 11-5. Box and whisker plots of Loring Pond TSI data for the most recent 10 years. Horizontal lines represent MPCA eutrophication standard for shallow lakes. See Appendix A for the entire period of record.

2015 Water Resources Report – Minneapolis Park & Recreation Board Page 11-6 LAKE AESTHETIC AND USER RECREATION INDEX (LAURI)

The LAURI for Loring Pond is shown in Figure 11-6. In 2015, Loring Pond scored “excellent” in aesthetics and water clarity. Loring scored “good” in habbitat quality. Loring Pond does not have a swimming beach and was therefore not scored for public health. Loring does not have boat or canoe access and therefore scored a “poor” in recreational access. Details on the LAURI index can be found in Section 1.

Figure 11-6. The 2015 LAURI for Loring Pond.

2015 Water Resources Report – Minneapolis Park & Recreation Board Page 11-7 WINTER ICE COVER

Ice came off Loring Pond on March 23, 2015, 10 days earlier than average ice-off date. Ice came on to the pond on December 21, 2015, 20 days later than the average ice-on date for Loring Pond. Loring Pond is a popular spot for geese, ducks and gulls, and some years waterfowl keep an open hole of water from freezing past normal ice-on. See Section 1 for details on winter ice cover records and Section 18 for a comparison with other lakes.

PHYTOPLANKTON AND ZOOPLANKTON

Phytoplankton and zooplankton are the microscopic plant and animal life that form the foundation of the food web in lakes. Zooplankton preferentially graze on phytoplankton and play a part in water clarity. Figure 11-7 shows the Secchi transparency, chlorophyll-a concentrations, and relative abundance of phytoplankton division and Figure 11-8 shows the zooplankton abundance in 2015.

The winter sample contained the highest algal biomass (chlorophyll-a concentration of 28 µg L-1) and was comprised of cryptomonads and green algae (Chlorophyta). Water transparency started high (3 m) in April, slowly decreased to about 1 meter through June and fluctuated between 1-3 meters the remainder of the season. Chlorophyll-a concentrations were low for the entire open water season (< 12 µg L-1) with a phytoplankton community comprised of mostly cryptomonads for much of the year with green algae becoming more abundant in August. Euglenoids, dinoflagellates (Pyrrhophyta), diatoms (Bacillariophyta), and a small amount of blue green algae (Cyanophyta) were also present throughout the year.

Zooplankton density at Loring Pond in 2015 is shown in Figure 11-8. A high number of cladocerans, primary grazers of algae, were present in Loring for much of 2015. Nauplii and juvenile zooplankton were present every month, but were the most abundant in June and September. Rotifers were only present in small numbers May, June, September and October.

2015 Water Resources Report – Minneapolis Park & Recreation Board Page 11-8

Figure 11-7. Secchi transparency (a), chlorophyll-a concentration (b), and relative abundance of phytoplankton (c) during the 2015 Loring Pond sampling season. Note that the Secchi depth axis is reversed.

2015 Water Resources Report – Minneapolis Park & Recreation Board Page 11-9

Figure 11-8. Zooplankton distribution at Loring Pond during the 2015 sampling season.

FISH STOCKING

Additional information and a definition of fry, fingerling, yearling, and adult fish sizes can be found in Section 1.

Loring Pond was stocked by MDNR in: 2001 with 417 adult Black Crappie, 465 adult Bluegill Sunfish. 2002 with 268 adult Black Crappie, 423 adult Bluegill Sunfish. 2003 with 107 adult Black Crappie, 417 adult Bluegill Sunfish. 2004 with 102 adult Black Crappie, 485 adult Bluegill Sunfish. 2005 with 100 adult Black Crappie, 402 adult Bluegill Sunfish, 50 adult Channel Catfish. 2006 with 102 adult Black Crappie, 400 adult Bluegill Sunfish, 50 adult Channel Catfish. 2007 with 158 adult Black Crappie, 200 adult Bluegill Sunfish. 2008 with 200 adult Black Crappie, 400 adult Bluegill Sunfish, 50 adult Channel Catfish. 2009 with 102 adult Black Crappie, 403 adult Bluegill Sunfish. 2010 with 108 adult Black Crappie, 402 adult Bluegill Sunfish, 50 adult Channel Catfish. 2011 with 79 adult Black Crappie, 329 adult Bluegill Sunfish, 28 adult Channel Catfish. 2014 with 92 adult Black Crappie, 35 adult Blugill Sunfish, 75 adult Channel Catfish

2015 Water Resources Report – Minneapolis Park & Recreation Board Page 11-10

WATER QUALITY PROJECTS

In the summer of 2012, MPRB contracted with Applied Ecological Services (AES) to begin a multi- year project to reduce the cattail monoculture in a select area on the South Bay of Loring pond. Working under MDNR Aquatic Plant Permits, the 2012-2014 project included removal of hybrid and narrow-leaf cattail in a 15-foot area in front of the outlet structure, an area 25 feet in either direction from the center point of the dock, and a 100-foot long restoration area on the south shore. The 100 foot restoration area was to have cattails removed and the area planted with native aquatic emergent vegetation. Maintenance of the 100 foot restoration zone plantings and removal of cattails near the dock and outlet structure has been continuous.

In the fall of 2014, the AES contract was expanded to include cutting as many cattails as possible beneath the water surface. AES cut as many cattails as possible below the water in an effort to suffocate cattails and prepare the site for future vegetation management. It was anticipated that cutting cattails during this timeframe would either kill or reduce cattail populations the following growing season in 2015.

During the fall 2014 cattail cutting project, AES found that the North Bay was predominantly a floating mat of cattails and there were also additional floating mats in the South Bay. It is not possible to cut floating mats of cattails below the surface of the water since the mats float higher in the water when the cattails are cut. Additionally, it was found during this process that there were many cattails growing in shallow water further up the shore, none of which could be cut beneath the surface of the water.

Through Minnesota State Legislative action passed in 2014, the MPRB was “authorized to remove all hybrid and narrow-leaved cattails by mechanical removal and chemical control at Loring Lake…and replant the shoreland with native species…” (2014 Minnesota Session Laws, Chapter 290, Sec. 60).

As a result of the Legislative action, the MPRB solicited Request for Proposals in early 2015 to implement a larger project to control cattails and replanting with native aquatic emergent vegetation into both the South and North bays of the lake. The MPRB entered into a contract with AES for three years (2015-2018) with the exception of the North Bay work. Due to the complexity and cost of removing the large cattail mat in the North Bay, this project was taken off the scope of contracted work. AES work in the North Bay was only for cattail control during the 2015 growing season and winter (2015-2016) removal of cattail stems from the floating mat.

The fall 2014 below water cutting was very successful tool to control cattails in open water areas. A second cutting was necessary and this work was done by the contractor in August 2015 using brush saws, loppers and hand pruners either from a boat or from the shore. Herbicide treatments were applied to the floating mats and to cattails that were growing in saturated soils in early September 2015. Work in the North Bay included below water cutting and herbicide treatment of the floating mat during the growing season.

A good amount of native emergent plants that were part of the 1999 shoreline planting project were found to be thriving once the cattails were removed. Most notably, large patches of sweet flag on the north end of the south pond remain intact.

2015 Water Resources Report – Minneapolis Park & Recreation Board Page 11-11 12. LAKE NOKOMIS

HISTORY

In 1907, the Minneapolis Park and Recreation Board (MRPB) purchased open water, wetland and a peat bog known as Lake Amelia, later renamed Lake Nokomis. At that time, wetlands were viewed as unsanitary, so Theodore Wirth developed a plan to make the area more desirable for development and to protect public health. Dredging began in 1914, moving nearly 2.5 million cubic yards of material to increase the park by 100 acres, create beaches, solid shoreline, and parkways around the lake. Wirth predicted that the new parkland would settle, it did, and was corrected by a 1934 Works Progress Administration project.

Numerous restoration projects have been implemented to improve water quality in the lake, many projects undertaken were those recommended by the Blue Water Commission report (BWC, 1998). Carp were seined from the lake during the winter of 2001-02 in order to limit internal phosphorus loading caused by the fish foraging in the sediment. Increased street sweeping, grit chambers and wetland detention ponds were also implemented in 2001. An inflatable weir was installed in 2002 to prevent nutrients from Minnehaha Creek from entering the lake and was operational in 2003. In 2012, Minnehaha Creek Watershed District (MCWD) replaced it with a more durable fixed weir which allows the lake to overflow during periods of high water, yet still prevent the creek from flowing into the lake. A photograph of Lake Nokomis is presented below in Figure 12-1. Figure 12- 2 is a bathymetric map of Lake Nokomis and Table 12-1 contains morphometric data.

Figure 12-1. Lake Nokomis dock at sunrise in 2016.

2015 Water Resources Report – Minneapolis Park & Recreation Board Page 12-1

Figure 12-2. Bathymetric map of Lake Nokomis based on data collected by the Minnehaha Creek Watershed District.

Table 12-1. Nokomis Lake morphometric data.

Surface Mean Watershed: Residence Max Depth Littoral Volume Watershed Area Depth Lake Area Time (m) Area* (m3) Area (acres) (acres) (m) (ratio) (years) 204 4.3 10.1 51% 3.54x106 869 4.3 4.0 * Littoral area defined as less than 15 feet deep.

Lake Nokomis is a shallow polymictic lake which mixes many times during the growing season. Mixing potential is increased when higher than normal wind speeds occur along the north-south fetch of the lake. This has the effect of destabilizing the water column and mixing hypolimnetic phosphorus into the surface water where it can be utilized by algae near the surface.

2015 Water Resources Report – Minneapolis Park & Recreation Board Page 12-2 LAKE LEVEL

Weekly lake levels at Lake Nokomis from 1999 through 2015 are shown in Figure 12-3. In 2003, a new staff gage was surveyed in at the Lake Nokomis outlet. The ordinary high water level (OHW) designated by the MDNR for Lake Nokomis is 815.4 ft msl. The designated OHW is an estimate of the highest regularly sustained water level that has made a physical imprint on the land. See Section 18 for a comparison between other MPRB lake levels. Nokomis lake levels were very low for several years (2003-2011) due to a combination of factors including: several consecutive drought years, less discharge from the Mother Lake watershed, and the separation from Minnehaha Creek. Higher levels were recorded in 2011-2013 after large snowmelt and spring rains. Heavy rains between April and June resulted in the highest water levels ever recorded in Lake Nokomis and flooding issues around the lake lasted until late 2014. The 2015 levels were lower with two peaks in July and November due to above average precipitation during those months.

Figure 12-3. Lake levels recorded at Lake Nokomis, 1999-2015. The horizontal line represents Lake Nokomis OHW elevation (815.4 ft msl).

WATER QUALITY TRENDS – TROPHIC STATE INDEX (TSI)

The Lake Nokomis TSI scores over time are shown in Figure 12-4. There has been no significant change in TSI scores from 1992-2015 (p > 0.05); however, there has been a trend towards lower TSI scores in recent years. Lake Nokomis’s 2015 TSI score is 55 and the second lowest score observed since 1992. This value puts Nokomis between the 50th and top 25th percentile compared to other lakes in our ecoregion (based on calculations from the Minnesota Pollution Control Agency, using the Minnesota Lake Water Quality Data Base Summary, 2004). A detailed explanation of TSI can be found in Section 1.

2015 Water Resources Report – Minneapolis Park & Recreation Board Page 12-3

Figure 12-4. Lake Nokomis TSI scores and linear regression from 1992-2015.

BOX AND WHISKER PLOTS

Figure 12-5 shows box and whisker plots of Secchi transparency, chlorophyll-a, and total phosphorus data for Lake Nokomis for the most recent 10 years of data. Lake Nokomis site specific standards are indicated by a horizontal line on the box plot graphs. The US EPA approved a new 50 µg L-1 TP standard for Lake Nokomis in 2013 (MPCA, 2011). A detailed explanation of box and whisker plots can be found in Section 1. Data in box and whisker format from the entire period of record can be found in Appendix A.

The relatively wide range in the Lake Nokomis data may be due to the polymictic nature of the lake. Years with more mixing events and less stable stratification may result in greater phosphorus return from the sediments and more algal productivity near the surface.

Secchi transparency in 2015 had a longer clear water phase in the spring than previous years, but the average Secchi depth for the summer did not meet MPCA eutrophication standards. Chlorophyll-a and total phosphorus were some of the lowest concentrations observed in recent years and both met the MPCA standard (Figure 12-5). A MCWD-led biomanipulation project began in 2010 at Lake Nokomis, which aimed to reduce sediment disturbance by burrowing fish. While there appears to be a change in the fish community away from burrowing species based on fish surveys, the project may now be having a positive effect on clarity as there is a lower level of sediment phosphorus release (MCWD, 2013). Future monitoring will continue to show how effective this approach is on water quality in Lake Nokomis.

2015 Water Resources Report – Minneapolis Park & Recreation Board Page 12-4

Figure 12-5. Box and whisker plots of Lake Nokomis TSI data from the last ten years. Horizontal lines represent Lake Nokomis site specific eutrophication standards. See Appendix A for the entire period of record

BEACH MONITORING

Bacteria levels were monitored at Nokomis Main Beach and Nokomis 50th Street Beach during 2015. As shown in Table 12-2, the season long geometric mean for Escherichia coli (E. coli) was low for both beaches. There were no closures at either beach on Lake Nokomis during the 2015 beach season. Further details on MPRB beach monitoring can be found in Section 19.

2015 Water Resources Report – Minneapolis Park & Recreation Board Page 12-5 Table 12-2. Summary of 2015 E. coli results (MPN colonies per 100 mL) on Lake Nokomis beaches.

Statistical Calculations Nokomis 50th Nokomis Main Number of Samples 13 13 Minimum 8 9 Maximum 100 78 Median 26 37 Mean 39 37 Geometric Mean 27 29 Max 30-Day Geo Mean 59 60 Standard Deviation 33 23

Figure 12-6 shows the box and whisker plots for E. coli sampling results (MPN per 100 mL) for data collected over the past ten years. The dashed red line represents the E. coli standard for the 30-day geometric mean (126 MPN/100mL) and the dark red line represents the single-sample maximum standard (1260 MPN/100mL). The box and whisker plots show the data distribution for the sampling between years.

Figure 12-6. Box plots of Nokomis beach E. coli results (MPN per 100 mL), 2006–2015. The dashed horizontal line represents the E. coli standard for the 30-day geometric mean (126 MPN/100mL) and the solid horizontal line represents the single-sample maximum standard (1260 MPN/100mL). Note the log scale on the Y-axis. From 2006-2009 E. coli concentrations were determined as colony forming units (CFU/100ml).

2015 Water Resources Report – Minneapolis Park & Recreation Board Page 12-6 LAKE AESTHETIC AND USER RECREATION INDEX (LAURI)

Figure 12-7 shows the LAURI scores for Lake Nokomis. In 2015, the lake scored “excellent” in aesthetics, public health and recreation access. Water clarity and habitat quality were scored as “good.” Large amounts of algae typically limit water clarity which prevents light from penetrating into the water column and limits the amount of plant growth in the lake. See Section 1 for details on the LAURI index.

Figure 12-7. The 2015 LAURI Index scores for Lake Nokomis.

2015 Water Resources Report – Minneapolis Park & Recreation Board Page 12-7 WINTER ICE COVER

Ice came off Lake Nokomis on March 26, 2015, 10 days earlier than average ice-off for the lake. Ice came back on to the lake for the winter on December 28, 2015, which was 26 days later than average for the lake. See Section 1 for detailed winter ice records and Section 18 for comparison with other lakes.

EXOTIC AQUATIC PLANT MANAGEMENT

The MDNR requires a permit to remove or control Eurasian watermilfoil. Permits limit the area from which milfoil can be harvested in order to protect fish habitat. The permits issued to the MPRB allow for harvesting primarily in swimming areas, boat launches and in shallow areas where recreational access is necessary. The permitted area on Lake Nokomis was 15 acres, which is just under 15% of the littoral zone (area shallower than 15 feet). In 2015, approximately 1,200 pounds of aquatic plants was removed from the beach areas at Lake Nokomis using SCUBA divers. See Section 1 and Section 20 for details on aquatic plants.

PHYTOPLANKTON AND ZOOPLANKTON

Phytoplankton and zooplankton are the microscopic plant and animal life that form the foundation of the food web in lakes. Figure 12-8 shows the Secchi transparency, chlorophyll-a concentrations, and relative abundance of phytoplankton divisions and Figure 12-9 shows the zooplankton abundance during the 2015 sampling season. Blue green algae (Cyanophyta) comprised much of the phytoplankton community for most of the year. There was a greater abundance of diatoms (Bacillariophyta) and chrysophytes in the spring samples and diatoms stayed at a low abundance the remainder of the year. Green algae (Cyanophyta), cryptophytes, euglenoids, haptophytes and dinoflaggelates (Pyrrhophyta) were all present in low numbers in 2015. Water clarity was greater than 1.5 meters for the entire spring and early summer and dropped to less than 1 meter from the end of July through September, when chlorophyll-a concentrations were the highest.

The 2015 zooplankton distribution in Lake Nokomis is shown in Figure 12-9. Nauplii and juveniles were present in high numbers throughout the season, peaking in September. Rotifers were also present the entire year and were most abundant from May through August. Cladocerans, the primary grazers, were present in each sample with high densities in July and October. Calanoid, cyclopoids, and protozoa were present in small numbers during the year as well.

2015 Water Resources Report – Minneapolis Park & Recreation Board Page 12-8

Figure 12-8. Secchi transparency (a), chlorophyll-a concentration (b), and relative abundance of phytoplankton (c) during the 2015 Lake Nokomis sampling season. Note that the Secchi depth axis is reversed.

2015 Water Resources Report – Minneapolis Park & Recreation Board Page 12-9

Figure 12-9. Zooplankton distribution in 2015 in Lake Nokomis.

FISH STOCKING Additional information and a definition of fry, fingerling, yearling and adult fish can be found in Section 1.

Lake Nokomis was stocked by the MDNR in: 1998 with 400 fingerling Tiger Muskellunge. 1999 with 82,144 fry Tiger Muskellunge, 773 fingerling Walleye, 46 yearling Walleye. 2000 with 300 fingerling Tiger Muskellunge. 2001 with 8,065 fingerling Walleye. 2002 with 300 fingerling Tiger Muskellunge. 2003 with 7,873 fingerling Walleye. 2005 with 4,266 fingerling Walleye. 2006 with 300 fingerling Tiger Muskellunge. 2007 with 740 yearling Walleye, 63 fingerling Walleye, 156 adult Walleye. 2009 with 458 fingerling Tiger Muskellunge and 7,718 fingerling Walleye. 2010 with 200 fingerling Tiger Muskellunge. 2011 with 9,376 fingerling Walleye.

2015 Water Resources Report – Minneapolis Park & Recreation Board Page 12-10 2012 with 200 Tiger Muskellunge and 2,000 yearling Walleye. 2013 with 8,476 fingerling Walleye. 2014 with 200 fingerling Tiger Muskellunge. 2015 with 495 yearling Walleye

2015 Water Resources Report – Minneapolis Park & Recreation Board Page 12-11 13. POWDERHORN LAKE

HISTORY

Powderhorn Lake was acquired by the Minneapolis Park and Recreation Board (MPRB) in 1890 and was named because its original shape resembled a gun’s powderhorn. Dipper dredge operations were conducted shortly thereafter from 1894 to 1904. Between 1924 and 1925 the south end of the lake was deepened by hydraulic dredging with nearly 150,000 cubic yards of spoils used to fill the north half to create parkland. Powderhorn Lake has always been a very popular neighborhood lake. It has been stocked by the MDNR as a Fishing in the Neighborhood (FiN) lake since 1980. Powderhorn Park hosts several large community events including the May Day Festival and the Powderhorn Art Festival.

Figure 13-1. Powderhorn Lake in 2013.

Powderhorn is a shallow lake with an island and one deeper hole at its southeastern end (Figures 13- 1 and 13-2, Table 13-1). Computer modeling indicates the lake was historically eutrophic (MPRB, 1999). Restoration activities were implemented as early as 1975 when a temporary summer aerator was installed to increase oxygen content in deeper water and to prevent fish kills. In 1995, a permanent winter aeration system was installed with the MDNR to provide a refuge for fish and prevent winter fish kills. Lake water levels are occasionally augmented with groundwater.

The MPRB and Minneapolis Public Works developed a major restoration plan for Powderhorn Lake in 1999. In 2001, five continuous deflective separation (CDS) grit chambers were installed to remove solids from stormwater inflow. In 2002, native plants were planted to improve aesthetics and habitat, and to filter overland flow from the park. Restoration also included repairing the Works Progress Administration (WPA) stone wall, removing concrete sluiceways, and installing a permanent summer aerator. An alum treatment was conducted in May 2003 to limit phosphorus availability. The combined effects of these restoration projects have improved water quality in Powderhorn Lake; however, the large amount of stormwater entering the lake from its watershed inhibits further improvement.

2015 Water Resources Report – Minneapolis Park & Recreation Board Page 13-1 The MPRB has applied barley straw treatments at Powderhorn every spring since 2004 to control algal growth. While it is difficult to ascertain which restoration activities have benefited the lake the most, the barley straw treatments seem to have been an important tipping point for improving water clarity in some years. Macrophyte beds were first noted in 2006 and led to improved clarity and lower nutrient levels in the lake. In 2010, extensive duckweed (Lemna spp.) beds covered the lake and shaded out macrophyte growth. Filamentous algae dominated large portions of the lake bed and water surface from 2011 to 2013. More recently, there has been summer blue-green algal blooms in the lake. The decomposition of thick plant and algae growth combined with a hot dry summer often creates low oxygen levels in the lake.

Restoration efforts shifted in 2007 when the invasive species Egeria densa (Brazilian waterweed) was discovered growing in several small stands in the lake. During the fall of 2007, the MDNR treated the invasive plant with herbicide Diquat to target and eradicate the unwanted species. At the request of the MDNR, the MPRB did not use the Powderhorn Lake winter aeration system during the winter of 2007. The invasive plant has not been identified in the lake since the herbicide treatment and was removed from the infested waters list for this species in 2014. The DNR based the decision off of 5 years of surveys indicating no presence of Egeria densa.

Powderhorn Lake Bathymetry

H 33RD

T

4 1

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0

15

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34 1/2

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H

050 100 200 300 400 500 Feet Water Depth Contours Bathymetry of Powderhorn Lake. Fieldwork by MDNR 1963. Streets Contours provided by MDNR, digitized by MPRB. Paths Additional data provided by the City of Minneapolis.

Figure 13-2. Bathymetric map of Powderhorn Lake.

2015 Water Resources Report – Minneapolis Park & Recreation Board Page 13-2 MPCA removed Powderhorn Lake from the US EPA 303(d) list of impaired waters in 2012 due to a strong trend towards improved water quality. However, the lake has not met standards for clarity or chlorophyll-a the past three years and if the trend continues it could be put back on the list. MPCA and MPRB will continue to evaluate the lake for potential improvement options. Improving oxygen levels, reducing trash accumulation, and reducing algae growth are all areas where improvements could continue at the lake.

Table 13-1. Powderhorn Lake morphometric data.

Surface Mean Watershed: Residence Maximum Littoral Volume Watershed Area Depth Lake Area Time Depth (m) Area* (m3) Area (acres) (acres) (m) (ratio) (years) 11 1.2 6.1 99% 5.43x104 286 26.0 0.2 * Littoral area was defined as less than 15 feet deep.

LAKE LEVEL

Powderhorn Lake levels are recorded weekly during the ice free season and are shown in Figure 13-3 from 1999 through 2015. Water levels were normal in the spring and increased to some of the highest levels recorded for the lake and flooding part of the fishing dock for much of the summer. In the fall the outlet pump was turned on and 9.9 million gallons were pumped out of the lake to accommodate repair work on the Tea House. Powderhorn Lake levels are occasionally augmented with a groundwater well. There is no MDNR designated ordinary high water level (OHW) for Powderhorn Lake. See Section 18 for comparison with other MPRB lake levels.

Figure 13-3. Powderhorn Lake levels from 1999  2015.

2015 Water Resources Report – Minneapolis Park & Recreation Board Page 13-3 AUGMENTATION WELL

A groundwater well is used to maintain the water level at Powderhorn. The MDNR issues permits and determines pumping limits for augmentation wells. In 2006, the permitted pumping volume decreased from 26 million gallons per year to 10 million gallons per year. MPRB staff records groundwater usage monthly. Table 13-2 shows the annual water usage since 2011. The groundwater pump was used in April of 2015, pumping roughly 1.3 million gallons into the lake. See Section 1 for detailed information on MPRB augmentation wells.

Table 13-2. Powderhorn Lake yearly pumping volume in gallons.

2011 2012 2013 2014 2015 Total (gal) Total (gal) Total (gal) Total (gal) Total (gal) 10,371,600 8,014,500 3,261,600 0 1,282,500

WATER QUALITY TRENDS – TROPHIC STATE INDEX (TSI)

Powderhorn Lake has historically been eutrophic due to high nutrient levels. Figure 13-4 shows TSI scores and a regression line for Powderhorn Lake. Powderhorn Lake has a TSI score of 71 in 2015 and is below average for the Northern Central Hardwood Forest ecoregion falling in the 75th percentile for this ecoregion based on calculations from the Minnesota Pollution Control Agency, using the Minnesota Lake Water Quality Data Base Summary, 2004. There is no linear trend in TSI scores with water quality fluctuating over the past 20 years. The restoration efforts improved TSI scores from 2001-2009. CDS units decreased phosphorus, solids, and sediment inputs, annual barley straw treatments increased water clarity, and an alum treatment briefly decreased phosphorus and increased water clarity. However, the trend is changing towards higher TSI scores and lower water quality since 2009. A detailed explanation of TSI can be found in Section 1.

Figure 13-4. Powderhorn Lake TSI scores and linear regression. The blue square highlights the 2003 alum treatment.

2015 Water Resources Report – Minneapolis Park & Recreation Board Page 13-4 BOX AND WHISKER PLOTS

Figure 13-5 shows box and whisker plots for the Powderhorn Lake data for the past ten years. MPCA shallow lake standards are shown as a horizontal line across the graph. A further detailed explanation of box and whisker plots can be found in Section 1. Box and whisker plots from the entire period of record from Powderhorn Lake can be found in Appendix A.

Figure 13-5. Box and whisker plots of data from Powderhorn Lake: 2006-2015. Horizontal lines represent MPCA eutrophication standard for shallow lakes. See Appendix A for the entire period of record.

2015 Water Resources Report – Minneapolis Park & Recreation Board Page 13-5 Marked improvements in the TSI parameters have been seen in Powderhorn Lake during the restoration projects, but have gone back to pre-restoration levels in recent years. The Secchi transparency, chlorophyll-a and total phosphorus concentrations in 2015 were similar to the previous two years and none of them met MPCA eutrophication standards. As shown in Appendix A, 2015 resemble data from the late 1990s more than the mid-2000s. Nitrogen levels remain lower than pre-2001 levels, as shown in Figure 13-6. It is unknown why nitrogen levels have decreased so drastically. CDS units and grit chambers were installed in the watershed at this time, but the mechanism by which these BMPs would influence nitrogen is not known.

Figure 13-6. Total nitrogen data from Powderhorn Lake: 1992- 2015.

LAKE AESTHETIC AND USER RECREATION INDEX (LAURI)

The LAURI for Powderhorn Lake is shown in Figure 13-7. In 2015, Powderhorn Lake scored “excellent” in aesthetics and “good” in habitat quality. Powderhorn received a score of “poor” in recreational access and water clarity. Powderhorn Lake does not have a swimming beach and was not scored for public health. See Section 1 for details on the LAURI.

2015 Water Resources Report – Minneapolis Park & Recreation Board Page 13-6

Figure 13-7. The 2015 LAURI scores for Powderhorn Lake.

WINTER ICE COVER

Ice came off of Powderhorn Lake on March 25, 2015, ten days earlier than average. Ice came back onto the lake on December 21, 2015, which was 22 days later than the average ice-on date and tied 2001 for the latest ice-on date recorded on the lake. Waterfowl keep Powderhorn Lake open later in some years. See Section 1 for details on winter ice cover records and SSection 18 for a comparison with other lakes.

2015 Water Resources Report – Minneapolis Park & Recreation Board Page 13-7 PHYTOPLANKTON AND ZOOPLANKTON

Phytoplankton and zooplankton are the microscopic plant and animal life that form the foundation of the food web in lakes. Figure 13-8 shows the Secchi transparency, chlorophyll-a concentrations, and relative abundance of phytoplankton divisions and Figure 13-9 shows the zooplankton abundance during the 2015 sampling season.

Figure 13-8. Secchi transparency (a), chlorophyll-a concentration (b), and relative abundance of phytoplankton (c) during the 2015 Powderhorn Lake sampling season. Note that the Secchi depth axis is reversed.

2015 Water Resources Report – Minneapolis Park & Recreation Board Page 13-8

The phytoplankton community in the winter sample was greater than 60% dinoflaggelates (Pyrrhophyta), a group that is sometimes heterotrophic, gaining its resource requirements from ingesting particles from the water. Water clarity was poor (< 1 m) for the entire year with chlorophyll-a concentrations ranging from 6-70 µg L-1 and often exceeding 45 µg L-1 from June through September. The open water season was characterized by a phytoplankton community comprised of a mix of diatoms (Bacillariophyta), green algae (Chlorophyta), cryptomonads and blue green algae (Cyanophyta). Diatoms and green algae being more abundant in the spring before blue greens made up over 70% from July through October, when there was a visible blue-green scum on the surface of the lake.

Rotifers were at high levels in April, May and June. Interestingly, rotifers almost comprised the entire zooplankton sample in April along with a small number of nauplii and juvenile copepods. Cladocerans were present beginning in June and were abundant through September. Cyclopoids were present in Powderhorn, but only at low numbers (Figure 13-9).

Figure 13-9. Zooplankton distribution in Powderhorn Lake during 2015.

2015 Water Resources Report – Minneapolis Park & Recreation Board Page 13-9

FISH STOCKING

Additional fish stocking information can be found in Section 1.

Powderhorn Lake was stocked by the MDNR in: 1998 with 585 adult Bluegill Sunfish. 1999 with 501 adult Black Crappie, 1,008 adult Bluegill Sunfish, 9 adult Largemouth Bass. 2000 with 380 adult Black Crappie, 1,728 adult Bluegill Sunfish. 2001 with 510 adult Black Crappie, 1,002 adult Bluegill Sunfish. 2002 with 510 adult Bluegill Sunfish. 2003 with 422 adult Black Crappie, 1,614 adult Bluegill Sunfish. 2004 with 270 adult Black Crappie, 516 adult Bluegill Sunfish, 99 adult Channel Catfish. 2005 with 500 adult Bluegill Sunfish, 120 adult Channel Catfish. 2006 with 500 adult Bluegill Sunfish, 100 adult Channel Catfish. 2007 with 500 adult Bluegill Sunfish, 85 adult Channel Catfish. 2008 with 500 adult Bluegill Sunfish, 117 adult Channel Catfish, and 1 adult Largemouth Bass. 2009 with 499 adult Bluegill Sunfish, 75 adult Channel Catfish, 20 adult Largemouth Bass. 2010 with 623 adult Bluegill Sunfish, and 137 adult Channel Catfish. 2011 with 277 adult Bluegill Sunfish, 116 adult Channel Catfish, and 13 adult Largemouth Bass. 2012 with 711 adult Bluegill Sunfish, and 35 adult Channel Catfish. 2014 with 3 adult Black Crappie, 346 adult Bluegill Sunfish, 173 adult Channel Catfish, 4 adult Hybrid Sunfish, and 4 adult Pumpkinseed. 2015 with 300 adult Bluegill Sunfish, 251 adult Channel Catfish

WATER QUALITY PROJECTS

Water quality improvement projects have been implemented to improve the health of Powderhorn Lake and are detailed in the History section of this chapter. Barley straw was first used at Powderhorn Lake in 2004 when 250 pounds/acre were added. Barley straw is applied by staking loose bales below the surface of the water where it slowly decomposes. The first treatment appeared to have little effect. Application rates were increased to 364 lbs/ac or 4000 pounds for the lake, and appear to have been more successful. 2015 was the 12th application of barley straw to Powderhorn Lake.

2015 Water Resources Report – Minneapolis Park & Recreation Board Page 13-10 14. RYAN LAKE

HISTORY

Ryan Lake is a small body of water that borders the cities of Robbinsdale, Brooklyn Center, and Minneapolis (Figure 14-1). The Canadian Pacific Railway owns a rail line corridor in the Humboldt Industrial Park that runs along the northern shore of the lake. The City of Minneapolis owns land on the east side of the lake which is maintained by the Minneapolis Park and Recreation Board (MPRB). Private residents own the west and the south shores of Ryan Lake. The MPRB installed a new dock on the east side for use by the public in 2006. In the spring of 2006, a small rain garden was constructed. Figure 14-2 shows a bathymetric map of Ryan Lake and Table 14-1 shows the morphometric data on Ryan Lake.

Figure 14-1. View at Ryan Lake, 2012.

2015 Water Resources Report – Minneapolis Park & Recreation Board Page 14-1 Ryan Lake Bathymetry

O S 1:3,500 S E O

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0100 200 400 600 800 1,000 Feet Legend Water Wetland Bathymetry of Ryan Lake. Fieldwork by MDNR 1963. Contours georectified and digitized by MPRB 2010. Depth Contours Additional data provided by the City of Minneapolis. Streets

Figure 14-2. Bathymetric map of Ryan Lake.

2015 Water Resources Report – Minneapolis Park & Recreation Board Page 14-2 Table 14-1. Ryan Lake morphometric data. OHW= designated ordinary high water level.

Surface Area Max Littoral Watershed Watershed:Lake OHW (acres) Depth (m) Area* Area (acres) Area (ratio) (ft msl) 19 10.7 50% 5,510 306 849.6 *Littoral area was defined as less than 15 feet deep.

Ryan Lake has been monitored periodically through the Metropolitan Council’s Citizen Assisted Monitoring Program (CAMP) since 1994, but was not monitored in 2015. Over the years, the Ryan Lake CAMP score has fluctuated between a “B” and “D”, with a most recent score of a “B” in 2012. Additional information on the CAMP monitoring at Ryan Lake can be found through the Metropolitan Council on their Lake Monitoring and Assessment or the Shingle Creek Watershed Management Commission webpages.

Ryan Lake was listed on the Minnesota Pollution Control Agency’s list of impaired waters (303(d) list) for excess nutrients. A TMDL and an implementation plan were approved in 2007 along with the Twin Lake chain of lakes. In the five years following, multiple projects have focused on reducing phosphorus loading from the watershed, but more reduction is needed from both external and internal sources (Shingle Creek Watershed Management Commission, 2014). More information can be found on the MPCA webpage under the Twin and Ryan Lakes - Excess Nutrients TMDL Project.

WINTER ICE COVER

Ice was off of Ryan Lake on March 30, 2015, seven days earlier than average. Ice came back to Ryan Lake on December 21, 2015, 15 days later than the average ice-on date. See Section 1 for details on winter ice cover records and Section 18 for a comparison with other lakes.

FISH STOCKING

Additional information on fish stocking can be found in Section 1. Ryan Lake was stocked by MDNR in:

2004 with 20 adult Black Crappie, 30 adult Bluegill Sunfish, and 5 adult Largemouth Bass 2007 with 20 adult Black Crappie, 24 adult Bluegill Sunfish, 10 adult Largemouth Bass, and 8 adult Northern Pike. 2008 with 31 adult Bluegill Sunfish, and 100 Yellow Perch. 2009 with 20 adult Bluegill Sunfish, and 21 adult Yellow Perch. 2010 with 20 adult Black Crappie, 20 adult Bluegill Sunfish, and 20 adult Yellow Perch. 2011 with 20 adult Bluegill Sunfish, 20 Black Crappie, and 6 Largemouth Bass 2013 with 130 yearling Yellow Perch. 2014 with 9 adult Black Crappie, 14 adult Bluegill Sunfish, 3 adult Largemouth Bass, 9 adult Northern Pike, 15 adult Pumpkinseed, and 5 adult White Crappie.

2015 Water Resources Report – Minneapolis Park & Recreation Board Page 14-3 15. SPRING LAKE

HISTORY

Spring Lake is located to the west of Loring Pond adjacent to Kenwood Parkway and the Parade Stadium grounds in central Minneapolis. Spring Lake was acquired by the MPRB in 1893 through a special assessment requested by citizens. Today the lake appears secluded, but at the time of purchase, Spring Lake was the park’s focal point. In an unusual move for the time, a 2-acre area including the lake and surrounding land was designated as a bird sanctuary and kept in a natural state. Historic photos and documents show that the north side of the lake was once a lumberyard.

Despite being surrounded by parkland on three sides, Spring Lake receives a lot of urban runoff Figure 15-1. Highway 394 borders the northwest portion of the riparian zone and contributes stormwater runoff to the lake. Spring Lake also receives water from a 195-acre subwatershed of the Bassett Creek watershed. These urban stormwater inputs contribute to meromixis in Spring Lake. Meromictic lakes do not mix completely so that the deeper layers of the lake remain continually stratified. It is difficult to compare meromictic lakes with dimictic or polymictic lakes, since their chemical, physical, and trophic structures are much different.

The typical sampling schedule requires Spring Lake to be monitored every other year; however, the lake has been sampled each year since 2011 in order to assess the water quality effects of artificial islands (see Water Quality Projects section below). Table 15-1 shows morphometric data for the lake and Figure 15-2 shows a map of Spring Lake.

Figure 15-1. Spring Lake in October, 2011. Two of the artificial islands are visible.

2015 Water Resources Report – Minneapolis Park & Recreation Board Page 15-1

Figure 15-2. Spring Lake map.

Table 15-1. Spring Lake morphometric data. OHW=ordinary high water level.

Surface Watershed: Mean Maximum Volume Watershed OHW Area Lake Area Depth (m) Depth (m) (m3) Area (acres) (ft msl) (acres) (ratio) 3 3.0 8.5 3.65x104 45 15.0 820.46

2015 Water Resources Report – Minneapolis Park & Recreation Board Page 15-2 WATER QUALITY TRENDS – TROPHIC STATE INDEX (TSI)

Figure 15-3 shows the Spring Lake TSI scores and linear regression since 1995. In 2015, Spring Lake had a TSI score of 72, or hypereutrophic. There is no significant trend in TSI from 1995-2015 (p > 0.05). Spring Lake’s TSI scores and trend line must be viewed with caution as both are based on a limited number of samples and the number of samples collected in a season has changed over time. From 1999–2001, samples were collected quarterly and only one sample per year was collected during the growing season; therefore, a TSI score could not be calculated. During 2002, 2003, and subsequent odd-numbered years Spring Lake was sampled monthly in order to calculate a TSI score. A detailed explanation of TSI can be found in Section 1.

Figure 15-3. Spring Lake TSI scores and linear regression from 1995-2015.

BOX AND WHISKER PLOTS

The box and whisker plots in Figure 15-4 show the data distribution for the Secchi, chlorophyll-a, total phosphorus, and total nitrogen for Spring Lake over the last ten years. Horizontal lines indicate the MPCA nutrient criteria. The 303(d) assessment for impaired waters is limited to lakes of ten acres or greater (MPCA, 2014). Spring Lake is too small (3 acres) to be listed on MPCA’s impaired waters list; however, it is still useful to compare Spring’s data to the state standards to determine lake water quality. A detailed explanation of box and whisker plots can be found in Section 1. Data in similar format for the entire period of record can be found in Appendix A.

Spring Lake is eutrophic with considerable amounts of algae at times. High nutrient concentrations in the lake generally contribute to high algal growth and shallow Secchi depths. Total phosphorus levels were high and variable, ranging from 124 to 892 µg L -1. Chlorophyll-a concentrations were higher than the previous three years and more similar to pre-2011 values. Since 2011, duckweed (Lemna spp.) has covered the lake for much of the summer. The thick layer of duckweed can shade photosynthetic algae, leading to lower chlorophyll-a concentrations, and creating low dissolved oxygen levels. The fresh oxygenated layer that typically forms on the surface of Spring Lake was very thin to non-existent during the summer of 2015.

2015 Water Resources Report – Minneapolis Park & Recreation Board Page 15-3

Figure 15-4. Box and whisker plots of Spring Lake TSI data: 2006-2015. Horizontal lines represent MPCA eutrophication standard for shallow lakes. See Appendix A for the entire period of record.

2015 Water Resources Report – Minneapolis Park & Recreation Board Page 15-4

Figure 15-4 continued. Box and whisker plots of Spring Lake Total Nitrogen from 1995-2015.

WINTER ICE COVER

The ice came off Spring Lake on March 23, 2015, nine days earlier than average. Ice covered Spring Lake on December 18, 2015, 19 days later than the average ice-on date for the lake. See Section 1 for details on winter ice cover records and Section 18 for a comparison with other lakes.

PHYTOPLANKTON AND ZOOPLANKTON

Phytoplankton are the microscopic plant life that form the foundation of the food web in lakes. Chlorophyll-a is the main pigment used by phytoplankton for photosynthesis and can be used as a proxy for the density of phytoplankton growth. Figure 15-5 shows the Secchi transparency, chlorophyll-a concentrations, and relative abundance of phytoplankton divisions for Spring Lake in 2015. Although zooplankton weren’t sampled, observations of surface water noted bright red zooplankton on several occasions. Certain zooplankton can produce a substance similar to hemoglobin that they use to store oxygen when living in low-oxygen environments, making them appear red.

Water transparency remained fairly stable between 0.5-2 m for much of the open water season and closely mirrored chlorophyll-a concentration fluctuations. Cryptomonads, specificially the species Cryptomonas erosa, comprised the majority of the phytoplankton community for much of 2015 with relative abundances reaching 99% from July-October. Green algae (Chlorophyta) were present in the winter and spring, but were not present in the remainder of the year. In past sampled years, Spring Lake has had a diverse phytoplankton community; however since 2012, Spring Lake has exhibited a strongly homogenous phytoplankton population dominated by cryptomonads. Lemna cover in recent years may also be affecting the phytoplankton community composition, since C. erosa can survive in low light conditions.

2015 Water Resources Report – Minneapolis Park & Recreation Board Page 15-5

Figure 15-5. Secchi transparency (a), chlorophyll-a concentration (b), and relative abundance of phytoplankton (c) during the 2015 Spring Lake sampling season. Note that the Secchi depth axis is reversed.

WATER QUALITY PROJECTS

In August of 2011, the Minnesota Chapter of the American Society of Landscape Architects (ASLA), the Lowry Hill Neighborhood Association, and Blake School partnered with the MPRB to install seven floating artificial biohavens in Spring Lake (Figure 15-6). Funds for the project were donated by the Lowry Hill Neighborhood and Midwest Floating Islands. Volunteers planted the biohavens

2015 Water Resources Report – Minneapolis Park & Recreation Board Page 15-6 with a combination of native vegetation chosen as aggressive, pioneer species, cover plants, or plants with food value for birds. Each biohaven was planted with a unique combination of plant species.

The biohavens were intended to add aesthetic value, bird hhabitat, and potential water quality benefits to Spring Lake. The biohavens are composed of a high surface area reecycled plastic matrix, which will grow a biofilm together with root systems established by the plantings. As the biofilm and the plants on the biohaven grow, it is theorized that nutrients will be removed from the water and will be recycled back to the lake as the plants and biofilm senesce. Birds mayy be sources and sinks of nutrients for Spring Lake as they may eat seeds and fruits produced on the biohavens but may contribute nutrients from outside of the system as well.

Plant growth and biohaven performance were qualitatively monitored monthly during the growing season by MPRB. Regular monitoring of TSI parameters in Spring Lake will allow comparison between pre- and post-island years. Biohaven performance will be evaluated for usse in other MPRB projects such as stormwater ponds and shoreline restoration.

Figure 15-6. Locations of biohavens in Spring Lake.

2015 Observations

2015 marked the fourth full year since the biohavens were installed. The islands were inspected in July and were in need of repair (Figure 15-7). Three of the seven islands have detached and are resting around the lake. In the beginning of September, two of the islands were found resting near the dock. Purple loosestrife was present on three of the islands and made up a large percentage of the total vegetation on those islands at times. All the islands showed some signs of damage from animals (i.e. bent fences and/or exposed substrate).

2015 Water Resources Report – Minneapolis Park & Recreation Board Page 15-7

Island #1 Island #2 Island #3

Island #4 Island #5 Island #6

Figure 15-7. Condition of the floating islands in July 2015, there was no picture of island #7.

2015 Water Resources Report – Minneapolis Park & Recreation Board Page 15-8 16. WEBBER NATURAL SWIMMING POOL

HISTORY

Webber Park was named in 1939 for Charles C. Webber, who donated the land in memory of his late son. Originally, a dam across Shingle Creek created a 2-acre pool known as Camden Pond. Overflow water was used to fill a swimming pool in summer and the pond was used for ice skating in winter. In the 1950s, a flood prevention project rerouted Shingle Creek to the north to increase the drop in the creek from 1.5 to 5 feet. The project removed the dam that impounded Webber Lagoon and created the configuration of Webber Pond that existed until 2013.

Figure 16-1. Zero entry into Webber Natural Swimming Pool

On August 14, 2013, Webber Park was redeveloped to make way for the Webber Natural Swimming Pool (NSP). MPRB contracted BioNova Natural Pool and Landform companies to create the first public natural filtration swimming pool in the United States. The pool consists of two swimming basins (upper and lower pools) and a regeneration basin. Additionally, a stormwater pond was designed to treat runoff from the area surrounding the pool. Information on the stormwater pond can be found in Section 26. The pool’s total swimming area covers more than 21,000 square feet and contains approximately 500,000 gallons of water. The upper pool is smaller and shallower (3’7” depth). The lower pool features an open swimming area (6’4” depth), jumping platform area (11’7” depth) and lap swimming area (6’0” depth). The Webber NSP relies on a biological filtration system rather than chlorine disinfection to maintain water quality. Water flows from the swimming

2015 Water Resources Report – Minneapolis Park & Recreation Board Page 16-1 area through fine filters that remove particulate matter and then through a16,500 square foot regeneration pond to remove nutrients before returning to the swimming area. The regeneration basin contains plants, gravel and other aggregates, but does not contain any soil. Therefore, the plant and microbial communities must rely on the nutrients in the water to grow, making nutrients unavailable to nuisance algae. A complete cycle of water is drained out of the pool, circulated through the regeneration basin and pumped back into the pool occurs every 12 hours.

Construction was completed in June 2015 and the pool opened on July 24, 2015. However, it was only open during weekends because specialized aquatic robotic vacuums for maintaining pool did not work and new customized vacuums needed to be built. Without the robotic vacuums, increased maintenance (hand scrubbing and pressure washing) was needed the first few months of operation.

BACKGROUND

Since the water quality in the pool depends on the ecological conditions in the system, MPRB Environmental Management and Maintenance staff monitors the physical, chemical and biological parameters laid out in Table 16-1.

Fecal contamination of water is a potential health risk to the users of recreational waters. Escherichia coli (E. coli) is an indicator for fecal contamination in recreational waters. While indicator organisms themselves do not cause illness under normal conditions, they may indicate the presence of other disease causing pathogens. According to Bionova, Inc, the presence of elevated Enterococci indicates the presence of birds in the regeneration area and elevated Pseudomonas aeruginosa indicates the presence of excess sediment in the pool system, indicating that maintenance must be increased.

Potential sources of bacteria to the pool include: Wild and domestic animal waste, leaking diapers, bather defecation, organic debris, swimmers’ bodies, and naturalized growth on NSP surfaces.

From 2004 to the present, MPRB Environmental Management staff monitored the Minneapolis beaches for E. coli as an indicator of the presence of harmful bacteria as recommended by the US Environmental Protection Agency (USEPA). Knowledge gained from the E. coli monitoring program, along with EPA, World Health Organization (WHO), and FLL guidance has been used to create the Webber NSP standards and protocols.

The NSP at Webber Pond is held to a combination of current standards recommended by the German FLL (Forschungsgesellschaft Landschaftsentwicklung Landschaftsbau e.V.: Landscaping and Landscape Development Research Society), US EPA Beach Act STV standards (EPA, 2012), and WHO standards until US EPA or State of Minnesota approved standards are available for natural swimming pools. The FLL standards Scope of Validity (FLL, 2011) applies to “operation inspection, servicing, upkeep, and repair of outdoor pools with biological water purification used publicly, commercially, and not solely for private purposes.”

FLL 2011 standards note that Legionella bacteria testing is required in regular sampling if pool water is technologically heated. Since Webber NSP is not technologically heated, and is only heated by the sun, these bacteria will not be part of the regular sampling program at this time. Excess algal growth can not only be nuisance to swimmers, but also a safety concern if the blooms limit visibility to the bottom of the pool. Algal biomass is restricted by removing nutrients, most notably phosphorus, from the water and sequestering them in the plants and biofilms within the regeneration basin. Any fresh water used must first be run through a phosphate filter to limit the phosphorus concentration in the pool water.

2015 Water Resources Report – Minneapolis Park & Recreation Board Page 16-2

Table 16-1. List of physical, chemical and biological parameters along with the method used in 2015.

Parameter Sampling location MPRB method Upper pool, Lower pool, & Regeneration Escherichia coli SM 9223 Colilert basin or pump 1 Upper pool, Lower pool, & Regeneration Enterococcus Enterolert basin or pump 1 Upper pool, Lower pool, & Regeneration Pseudomonas aeruginosa Pseudolert basin or pump 1

Water transparency Upper pool & Lower pool Secchi Disk

Upper pool, Lower pool, & Regeneration Water temperature Temperature probe basin Upper pool, Lower pool, & Regeneration pH value pH probe basin Oxidative Reduction Water monitoring units in pumphouse ORP probe Potential (ORP) Upper pool, Lower pool, & Regeneration Conductivity Conductivity probe basin Upper pool, Lower pool, & Regeneration Luminescent dissolved oxygen Dissolved oxygen basin probe Upper pool, Lower pool, & Regeneration Alkalinity SM 2320 B. basin Upper pool, Lower pool, & Regeneration Total phosphorus SM 4500 P.E. basin Upper pool, Lower pool, & Regeneration Nitrate/nitrate USGS I-3520-85 basin Upper pool, Lower pool, & Regeneration Ammonia SM 4500 NO3 E. basin Upper pool, Lower pool, & Regeneration Hardness SM 2350 C. basin Upper pool, Lower pool, & Regeneration Chlorophyll -a SM 10200 H basin Phyto - rapid assessment and Phytoplankton/ Upper pool, Lower pool, & Regeneration biomass estimate zooplankton basin Zoop - horizontal tow 80 µm

2015 Water Resources Report – Minneapolis Park & Recreation Board Page 16-3

METHODS

Environmental Management staff monitors water in the upper pool, lower pool and regeneration basin for E. coli, Enterococci and Pseudomonas aeruginosa bacteria throughout the season. The bacteria samples for the regeneration basin we initially taken directly from the open water from May until late July when the sampling location was switched to the pump pumping water from the regeneration basin to the pool for the rest of the year based on a consultant’s recommendation. Bacteria samples were collected once a week in May after the pool was filled with water, two times a week in June, three times a week from July and August while the pool was open to the public and once a week again in September until the pool was drained for cleaning.

MPRB Maintenance staff records the water transparency by lowering a black and white 20-cm diameter Secchi disk into the deep diving well of the pool three times per day. Probes were installed in the pumphouse to monitor water temperature, pH and ORP, but the probes were not calibrated and the conductivity probe was not yet installed during the 2015 swim season. Therefore, a Hydrolab Minisonde 5 Multiprobe was used to record temperature, pH, conductivity, dissolved oxygen, and turbidity profiles during each visit to the pool to measure bacteria. The multiprobe was calibrated according to the manufacturer’s guidelines prior to each sampling trip.

Grab samples were taken from each basin (upper pool, lower pool and regeneration basin) for total phosphorus, nitrate/nitrate, ammonia, alkalinity, hardness, chlorophyll-a and phytoplankton enumeration. Both chlorophyll-a and phytoplankton samples were stored in opaque bottles for analysis with the phytoplankton samples preserved with a 25% glutaraldehyde solution. Horizontal zooplankton tow samples were taken in each basin using a 80-µm mesh tow net retrieved at a rate of 1 m/s. The 80-µm mesh was rinsed with distilled water or ethanol from the outside. The sample was preserved 90% denatured histological ethanol to a mix of approximately 50% sample 50% ethanol.

Immediately following collection all samples were placed on ice in a cooler and stored at approximately 4°C. Samples were transported to the contract laboratory for analysis within 8 hours of collection. Sampling procedures, sample preservation, and holding times followed procedures described in Standard Methods (2005) or US Environmental Protection Agency (US EPA, 1979 (revised 1983) and can be found in Table 16-1. The 2015 contract laboratory for chemical analyses was Instrumental Research, Inc. (IRI). PhycoTech, Inc. analyzed all phytoplankton and zooplankton samples.

RESULTS & DISCUSSION

Bacteria

E. coli concentrations were below the FLL standard of 100 MPN per 100 mL for much of the year, with a few samples in late July and early August that were above the FLL standard. A total of 94% of the samples met the FLL standard for E. coli. The only sample to exceed the EPA STV threshold was not taken from the pool, but rather the pump from the regeneration basin (Figure 16-2a and Figure 16-3a). Enterococci concentrations were similar to the E. coli results which are similar to the findings at the beaches, where enterococci and E. coli were strongly correlated (Section 18). A total of 83% of the enterococci samples met the FLL standard of 50 MPN per 100 mL, with the exceedances occurring at various times in June, July and August. Six of the samples exceeded the enterococci EPA STV threshold of 130 MPN per 100 mL (Figure 16-2b and Figure 16-3b). A total

2015 Water Resources Report – Minneapolis Park & Recreation Board Page 16-4 of 88% of the Pseudomonas aeruginosa samples met the FLL standard of 10 MPN per 100 mL. The only Pseudomonas sample that exceeded the WHO standard of 100 MPN per 100 mL occurred before the pool opened in May (Figure 16-2c and Figure 16-3c).

The elevated E. coli and enterococci numbers could be due to birds in the area. Although numerous anti-bird devices are used around Webber pool, the pool is located along a major flyway and it is difficult to deter every bird, especially at night. Pseudomonas is a common bacterium in soils and excess sediment in the pool is typically thought to be the cause of elevated concentrations. Extra cleaning around the pool followed elevated bacteria concentrations.

Figure 16-2. Webber pool E. coli (a), Enterococci (b) and Pseudomonas aeruginosa (c) concentrations in 2015. The dashed horizontal lines represent the FLL standard and solid horizontal lines represent either the EPA STV threshold for E. coli or Enterococci or the WHO guideline for Pseudomonas. Note the log scales on each y-axis.

2015 Water Resources Report – Minneapolis Park & Recreation Board Page 16-5

Figure 16-3. Webber pool E. coli (a), Enterococci (b) and Pseudomonas aeruginosa (c) concentrations in 2015 by pool (the regeneration basin was sampled in the open water until late July and the pump for the rest of the season). The dashed horizontal lines represent the FLL standard and solid horizontal lines represent either the EPA STV threshold for E. coli or Enterococci or the WHO guideline for Pseudomonas. Note the log scales on each y-axis.

2015 Water Resources Report – Minneapolis Park & Recreation Board Page 16-6 Water Chemistry

Pool water temperature met the FLL recommendation of less than 25 °C except for the end of July and early August. However, temperatures did not exceed 28 °C, which the FLL states can only be tolerated for up to five days (Figure 16-4a). The pH of the pool was initially higher than 9 in late May and early June, but remained around 8 the rest of the season (Figure 16-4b). The FLL recommends the pH of the pool to be between 6 and 8 since people with sensitive skin may experience some skin irritation with pH values greater than 9. Specific conductivity was within the FLL recommended range (200-1000 µS cm-1) the entire season (Figure 16-4c). Dissolved oxygen in the pool was also within the FLL recommended range (80-120%) (Figure 16-4d). The dissolved oxygen in the regeneration basin was supersaturated at times since the water is aerated with an air compressor prior to entering the basin and isn’t a concern for the pool.

Figure 16-4. Webber pool temperature (a), pH (b), conductivity (c), and dissolved oxygen (d) in 2015. The horizontal lines represent the FLL recommended values and the dashed horizontal lines represent acceptable levels as an exception according to the FLL.

The contractor initially responsible for the upkeep of the pool and wasn’t cleaning the pool as frequently as needed; therefore, it took a while for MPRB maintenance staff to catch up, leading to high algal abundance in late May and early June. Chlorophyll-a values then decreased to low (< 2 µg L-1) for the rest of the season (Figure 16-5a). Total phosphorus levels were initially above the FLL recommendation at over 0.100 mg L-1 due to the pool being filled using the city water supply which contains high levels of polyphosphate as an anti-corrosion agent. This likely fueled the algal bloom

2015 Water Resources Report – Minneapolis Park & Recreation Board Page 16-7 that occurred in June and most of it was removed using the fine filters. The total phosphorus levels decreased each month and fell within the FLL recommended value (< 0.01 mg L-1) by the end of the season (Figure 16-5b). Nitrate/nitrite concentrations were between 0.5 and 2 mg L-1 for the entire season and were well within the FLL recommendation of less than 30 mg L-1 (Figure 16-5c) Ammonia was also measured and was below detection (< 0.5 mg L-1) from June-September. Both alkalinity and hardness slowly increased throughout the season and were lower than the FLL recommended values of greater than 200 mg L-1 and 100 mg L-1 respectively (Figure 16-5d and 16- 5e).

Figure 16-5. Webber pool chlorophyll-a (a), total phosphorus (b), nitrate/nitrite (c), alkalinity (d) and hardness (e) in 2015. The horizontal lines represent the FLL recommended values.

2015 Water Resources Report – Minneapolis Park & Recreation Board Page 16-8 Phytoplankton

Phytoplankton biovolume by division is displayed in Figure 16-6. The June algal bloom is obvious and consisted of mainly green algae (Chlorophyta) and cryptomonads (Cryptophyta). Algal biomass was low the remainder of the year in the pools can was comprised of a mix of green algae and diatoms (Bacillariophyta). There was also a small amount of blue green algae (Cyanophyta) and haptophytes, but neither significantly contributed to the algal biomass. A bloom of filamentous algae in the regeneration basin occurred in August and led to high algal biovolume in that basin. Algal biomass was below the FLL recommended value of 1 mm3 L-1 in all three basins the entire year.

Figure 16-6. Webber pool phytoplankton biomass in 2015. The horizontal line represents the FLL recommended maximum value.

Zooplankton

Zooplankton was only abundant in June and July as shown in Figure 16-7. The zooplankton community is important for filtering bacteria in the pool water. Copepods have been found to have the greatest filtration capacity (64.8 ml/ind/day), followed by cladocerans (33.3 ml/ind/day) and rotifers (8.5 ml/ind/day) (Eydeler et al. 2010). The pool contained a mix of juvenile or nauplii copepods, cyclopoids and rotifers in June. There were a large number of cladocerans in both the upper and lower pools in July and Daphnia were visible in the deep diving well of the lower pool. There was also a large amount of Daphnia in the water tank between the pools and the fine filter tank when it was drained as part of a training exercise in July. The regeneration basin contained more rotifers than either pool basin. There was little zooplankton abundance in August and September.

2015 Water Resources Report – Minneapolis Park & Recreation Board Page 16-9

Figure 16-7. Webber pool zooplankton abundance in 2015.

2015 Water Resources Report – Minneapolis Park & Recreation Board Page 16-10 17. WIRTH LAKE

HISTORY

Wirth Lake was acquired by the Minneapolis Park and Recreation Board (MPRB) in 1909, enlarging the adjacent park from its previous size of 64 acres that was purchased in 1889. It was originally known as Keegan’s Lake and renamed to Glenwood Lake in 1890. The lake was renamed yet again in 1938 after Theodore Wirth at the end of his tenure as Park Superintendent. A plant nursery was established on the west side of the lake in 1910 that provided the system with plantings through 1980.

As with most other lakes in the MPRB system thousands of cubic yards of sediment from Wirth were dredged. The spoils were used to raise the parkland near Glenwood Avenue. Wirth Lake Beach was constructed with sand purchased from sources outside of the MPRB. The lake is shown below in Figure 17-1.

Figure 17-1. Boardwalk across the north side of Wirth Lake in 2015.

Wirth Lake is generally dimictic but can mix during extreme events if Bassett Creek backflows to the lake (Wirth Lake TMDL Report, 2010). Historically, the lake was considered oligotrophic to mesotrophic. Early restoration projects included Rotenone in 1977 to remove rough fish and subsequent stocking of channel catfish, largemouth bass, walleye, and bluegills. A summer aerator was installed and operated from the early 1980s until 1991. A portable winter aerator was used for a few years before a permanent aeration system was put in place in 2002. Figure 17-2 shows a bathymetric map of Wirth Lake and Table 17-1 shows the Wirth Lake morphometric data.

2015 Water Resources Report – Minneapolis Park & Recreation Board Page 17-1 Wirth Lake Bathymetry

HI GHWAY 55 H IGHWAY 55

0

2

0

Y O R 5 K

10

15 D T H O E O O W D N O E R L E G

W I R T H

1:4,500

0100 200 400 600 800 1,000 Feet Legend

Water Bathymetry of Wirth Lake. Fieldwork by MDNR 1963. Depth Contours Contours digitized and provided by MDNR. Additional data provided by the City of Minneapolis. Streets

Figure 17-2. Bathymetric map of Wirth Lake.

Table 17-1. Wirth Lake morphometric data.

Surface Watershed: Mean Maximum Littoral Volume Watershed Area Lake Area Depth (m) Depth (m) Area* (m3) Area (acres) (acres) (ratio) 39 4.3 7.9 59% 6.70x105 348 9.4 * Littoral area was defined as less than 15 feet deep.

2015 Water Resources Report – Minneapolis Park & Recreation Board Page 17-2 LAKE LEVEL

Wirth Lake levels are recorded weekly during ice free conditions. The lake levels for Wirth Lake are shown in Figure 17-3 from 1971 through 2015. The ordinary high water level (OHW) designated by the MDNR for Wirth Lake is 818.9 ft msl. The effects of new outlets installed in 1978 and in 1996 on water level fluctuations can be seen in the graph below. Since the installation of the 1996 outlet fewer high flow events have backed up water from Bassett Creek into the lake. The outlet to Bassett Creek Outlet was renovated and a new staff gauge was installed in August 2013. Lake levels were slightly higher for much of 2015, but only exceeded the OHW in late November after above average precipitation. See Section 18 for a comparison between other MPRB lake levels.

Figure 17-3. Lake levels for Wirth Lake from 1971–2015. Horizontal line represents Wirth Lake OHW elevation (818.9 ft msl).

WATER QUALITY TRENDS – TROPHIC STATE INDEX (TSI)

Figure 17-4 shows the Wirth Lake TSI scores over time. The 2015 TSI score for Wirth Lake was 46. Overall, there has been a significant decrease in TSI score from 1992-2015 (p < 0.05) with TSI scores being on average 15 TSI units lower in the past few years than when monitoring began. Wirth Lake now has a TSI score that falls within the 25th percentile category for lakes in this ecoregion (based on calculations from the Minnesota Pollution Control Agency, using the Minnesota Lake Water Quality Data Base Summary, 2004). A detailed explanation of TSI can be found in Section 1.

2015 Water Resources Report – Minneapolis Park & Recreation Board Page 17-3

Figure 17-4. Wirth Lake TSI scores and linear regression from 1992-2015.

BOX AND WHISKER PLOTS

The box and whisker plots in Figure 17-5 show the distribution of data for the Secchi, chlorophyll-a, and total phosphorus for Wirth Lake over the past ten years. The red horizontal lines indicate MPCA deep lake nutrient criteria. A detailed explanation of box and whisker plots can be found in Section 1. Data from the entire period of record in box and whisker format can be found in Appendix A.

The separation of Bassett Creek from Wirth Lake and upstream water quality improvements in the watershed may be responsible for continued improvement in Wirth Lake. Secchi transparency is increasing with deeper average readings, with 2015 being similar to the previous seven years. Both phosphorus and chlorophyll-a levels were also similar to recent years. All three parameters met the MPCA eutrophication standards in 2015.

2015 Water Resources Report – Minneapolis Park & Recreation Board Page 17-4

Figure 17-5. Box and whisker plots of Wirth Lake data from over the past ten years. Horizontal lines represent MPCA eutrophication standard for deep lakes. See Appendix A for the entire period of record.

2015 Water Resources Report – Minneapolis Park & Recreation Board Page 17-5 BEACH MONITORING

Bacteria levels were monitored weekly from June through August at Wirth Beach in 2015 (Table 17- 2). Figure 17-6 illustrates the box and whisker plots of E. coli sampling results (MPN per 100 mL) for all data collected between 2006 and 2015. Bacteria levels at Wirth Beach in 2015 were a little higher than the last couple years, but still similar to values recorded in previous years. Bacteria levels were low for much of the season with a season long geometric mean of 16 MPN per 100 mL. There were a few higher samples, but Wirth Beach remained open the entire swim season in 2015.

Table 17-2. Summary of E. coli results (MPN per 100 mL) for Wirth Beach in 2015.

Statistical Calculations Wirth Number of Samples 13 Minimum 2 Maximum 586 Median 10 Mean 85 Geometric Mean 16 Max 30-Day Geo Mean 69 Standard Deviation 179

Figure 17-6. Box and whisker plot of Wirth Beach E. coli results (colonies per 100 mL), for 2006–2015. The dashed horizontal line represents the E. coli standard for the 30- day geometric mean (126 MPN/100mL) and the solid horizontal line represents the single-sample maximum standard (1260 MPN/100mL). Note the log scale on the Y-axis. From 2004-2009 E. coli concentrations were determined as colony forming units (CFU/100ml).

2015 Water Resources Report – Minneapolis Park & Recreation Board Page 17-6 LAKE AESTHETIC AND USER RECREATION INDEX (LAURI)

The 2015 LAURI for Wirth Lake is shown in Figure 17-7. Wirth Lake scored “excellent” for aesthetics, habitat quality, public health, and recreational access opportunities and “good” for water clarity. Details on the updated LAURI can be found in Section 1.

Figure 17-7. Wirth Lake LAURI for 2015.

2015 Water Resources Report – Minneapolis Park & Recreation Board Page 17-7

WINTER ICE COVER

Ice came off Wirth Lake on March 26, 2015, seven days earlier than the average date for the lake. Ice came on to the lake for the winter on December 21, 2015, which was 21 days later than average and tied 2001 for the latest ice-on date recorded on the lake. Details on winter ice cover records can be found in Section 1 and a comparison with other lakes can be found in Section 18.

EXOTIC AQUATIC PLANT MANAGEMENT

The MDNR requires a permit to remove or control Eurasian water milfoil. Aquatic plant control permits limit the area from which milfoil can be harvested to protect fish habitat. The permits issued to the MPRB allow for harvesting at the beach and the boat launch. The permitted area on Wirth Lake was 5 acres which is 20% of the littoral zone of the lake (area shallower than 15 feet). A mechanical harvester could not be used inside of the beach boardwalk, so MPRB contracted SCUBA divers to remove vegetation from areas around the swimming beach, boardwalk, and boat launch. Approximately 3,700 pounds of aquatic plants were removed from Wirth Lake in 2015. See Section 1 and Section 20 for details on aquatic plants.

PHYTOPLANKTON AND ZOOPLANKTON

Phytoplankton and zooplankton are the microscopic plant and animal life that form the foundation of the food web in lakes. Figure 17-8 displays the Secchi transparency, chlorophyll-a concentrations, and relative abundance of phytoplankton division and Figure 17-9 shows the distribution of zooplankton sampled in 2015.

Water clarity initially started out poor in May with Secchi depths around 1 meter, but improved to between 2-5 meters for the remainder of the open water season. There was low algal abundance in 2015 with a maximum chlorophyll-a concentration of 14 µg L-1 with much of the year below 5 µg L-1. The phytoplankton community had a lot of turnover over the course of the year. The winter phytoplankton community was a mix of cryptomonads (Cryptophyta), haptophytes, diatoms (Bacillariophyta), green algae (Chlorophyta) and a small amount of blue green algae (Cyanophyta). Diatoms, haptophytes, dinoflaggelates (Pyrrhophyta), cryptomonads, chrysophytes and green algae comprised much of the spring and early summer samples and blue green algae and dinoflaggelates were more abundant in the summer. The winter sample was mostly cryptomonads; however, there was low algal abundance with chlorophyll-a levels below detection.

Zooplankton populations varied over the 2015 sampling season in Wirth Lake, as shown in Figure 17-9. Nauplii and juvenile zooplankton were at their highest levels throughout the early season and leveled off in late summer through fall. Cladocerans, primary grazers of phytoplankton, were present in throughout the year, but were in high numbers in the June and July samples. Rotifers were in low abundance in the spring and summer months but became more abundant in the fall. Cyclopoids and calanoids were only present in low concentrations in 2015.

2015 Water Resources Report – Minneapolis Park & Recreation Board Page 17-8

Figure 17-8. Secchi transparency (a), chlorophyll-a concentration (b), and relative abundance of phytoplankton (c) during the 2015 Wirth Lake sampling season. Note that the Secchi depth axis is reversed.

2015 Water Resources Report – Minneapolis Park & Recreation Board Page 17-9

Figure 17-9. Wirth Lake 2015 zooplankton distribution.

FISH STOCKING

Additional information and a definition of fry, fingerling, yearling, and adult fish sizes can be found in Section 1.

Wirth Lake was stocked by MDNR in: 1998 with 290 adult Black Crappie 258 adult Bluegill Sunfish. 1999 with 1,900 fingerling Channel Catfish. 2000 with 1,900 fingerling Channel Catfish. 2001 with 2,304 yearling Channel Catfish. 2003 with 600 adult Walleye. 2007 with 23,000 fry Walleye. 2008 with 40 adult Walleye and 57 fingerling Walleye. 2011 with 2,772 fingerling Walleye. 2012 with 23,000 fry Walleye.

2015 Water Resources Report – Minneapolis Park & Recreation Board Page 17-10 18. COMPARISON AMONG LAKES

PHYSICAL CHARACTERISTICS

Understanding the physical characteristics of a lake is important when interpreting data from an individual lake and when comparing groups of lakes. Shallow and deep lakes respond in distinct ways to environmental and watershed changes and may require entirely different approaches for rehabilitation. Lakes with large watershed to lake area ratios are typically more eutrophic and may be more complicated to manage if their watersheds cross political boundaries. A lake’s residence time can also influence its overall physical condition, with long residence times causing delayed effect of rehabilitation efforts. Table 18-1 presents the physical characteristics of the Minneapolis lakes.

Table 18-1. Minneapolis lakes physical characteristics.

Surface Mean Max Watershed Watershed: Residence Littoral Volume Lake Area Depth Depth Area Lake Area Time Area* (m3) (acres) (m) (m) (acres) (ratio) (years) Birch 5.8 ND ND ND ND ND ND ND

Brownie 18 6.8 15.2 67% 4.98x105 369 20.5 2.0

Calhoun 421 10.6 27.4 31% 1.80x107 2,992 7.1 4.2

Cedar 170 6.1 15.5 37% 4.26x106 1,956 11.5 2.7

Diamond 41 0.9 2.1† 100% 7.15x104 669‡ 16.3 ND

Grass 27 0.6 1.5 NA NA 386‡ 14.3 ND

Harriet 353 8.7 25.0 25% 1.25x107 1,139 3.2 3.4

Hiawatha 54 4.1 7.0 26% 8.95x105 115,840 2,145 0.03

Isles 103 2.7 9.4 89% 1.11x106 735 7.1 0.6

Loring 8 1.5 5.3 NA 4.88x104 24 3.0 ND

Nokomis 204 4.3 10.1 51% 3.54x106 869 4.3 4.0‡

Powderhorn 11 1.2 6.1 99% 5.43x104 286 26.0 0.2‡

Ryan 18 NA 10.7 50% ND 5,510 306 ND

Spring 3 3.0 8.5 ND 3.65x104 45 15.0 ND

Wirth 39 4.3 7.9 61% 6.70x105 348 9.4 ND * Littoral area defined as less than 15 feet deep. ND= No Data Available. NA= Not Applicable † Based on long-term data. ‡ Recent projects within the watersheds have altered these statistics.

2015 Water Resources Report – Minneapolis Park & Recreation Board Page 18-1 Summary statistics of interest include:

 Largest Lake: Lake Calhoun at 421 acres.  Smallest Lake: Spring Lake at 3 acres.  Deepest Lake: Lake Calhoun at 89 feet 11 inches.  Largest Watershed: Lake Hiawatha at 115,340 acres.  Smallest Watershed: Loring Pond at 24 acres.  Longest Residence Time: Lake Calhoun at 4.3 years.  Shortest Residence Time: Lake Hiawatha at 11 days.

WATER QUALITY TRENDS – TROPHIC STATE INDEX (TSI)

The Minneapolis Park and Recreation Board (MPRB) calculates a trophic state index score (TSI) for each lake using chlorophyll-a, Secchi depth, and total phosphorus measurements. TSI scores can be used to evaluate changes in an individual lake or to compare lakes to each other. Detailed information on TSI scores can be found in Section 1.

In 2015, MPRB water resources scientists monitored 11 of the city’s most heavily used lakes in order to calculate TSI scores. Figure 18-1 shows the 2015 TSI data plotted on the trophic state continuum. All of the Minneapolis lakes fell into the mesotrophic or eutrophic categories, which is the typical distribution for lakes in the North Central Hardwood Forest ecoregion (MPCA, 2004). With some exceptions, the deeper lakes had lower TSI scores than the shallow lakes. Scores for Diamond Lake should be viewed with caution since these lakes are too shallow to calculate the Secchi portion of the TSI index.

Changes in lake water quality can be tracked by looking for trends in TSI scores over time. Historical trends in TSI scores are used by lake managers to assess the effectiveness of restoration and management activities on the trophic state of the lakes. Comparing TSI trends in single lakes to trends seen in all of the lakes can help to identify whether changes in lake water quality may be due to climate cycles or to changes specific to a watershed.

Trends were identified by using a linear regression of the TSI scores through time. Table 18-2 shows the historical trends in TSI scores since 1991, the year sampling began for most lakes. Because the record for some lakes is so long, and because many large water quality improvement projects took place in the late 1990s and early 2000s, the long term water quality trend and 10-year trends for the Minneapolis lakes can be different. Table 18-3 shows the TSI trends since 2006. Graphs of TSI scores over the entire period of record for each lake are shown in Figures 18-2. For more detailed information on a particular lake’s trend in TSI scores and nutrient related water quality parameters, see the individual lake sections. Details on TSI scores and linear regression analysis can be found in Section 1.

2015 Water Resources Report – Minneapolis Park & Recreation Board Page 18-2 CARLSON'S TROPHIC STATE INDEX

WATER QUALITY TSI SCORE TROPHIC STATE 0 GOOD OLIGOTROPHIC

10

20 Clear water, little algae

30

2015 40 Lake Calhoun MESOTROPHIC Wirth Lake Lake Harriet Cedar Lake 50 Moderately clear water, Lake of the Isles some algae Lake Nokomis Lake Hiawatha EUTROPHIC Loring Pond 60

Diamond Lake Bluegreen algae prevalent Swimming impaired Powderhorn Lake 70 Spring Lake

80

90

Frequent noxious algae blooms

100 HYPEREUTROPHIC POOR

Figure 18-1. 2015 lake trophic state comparison. In general, the deeper lakes have lower TSI scores.

2015 Water Resources Report – Minneapolis Park & Recreation Board Page 18-3

Table 18-2. Water quality trends in Minneapolis lakes from 1991-2015.

Lakes with increasing Lakes with Lakes with decreasing water quality indicators stable trend water quality indicators

Lake Calhoun Cedar Lake Lake Nokomis Lake Harriet Wirth Lake Lake Hiawatha Lake of the Isles Loring Pond Powderhorn Lake Spring Lake

Table 18-3. Water quality trends in Minneapolis lakes from 2006-2015.

Lakes with decreasing Lakes with Lakes with increasing water quality indicators water quality indicators stable trend

Lake Calhoun Cedar Lake Lake Harriet Lake Nokomis Lake Hiawatha Powderhorn Lake Wirth Lake Lake of the Isles Loring Pond Spring Lake

Lakes Calhoun, Nokomis, and Wirth have all seen a significant improvement in water quality indicators since the early 1990s (linear regression, p < 0.1). Although Calhoun’s water quality is improved from the early 1990s, TSI scores have stabilized in the last 10 years. Lake Nokomis has seen a large improvement in water quality in the past few years following a biomanipulation project. The water quality improvement at Wirth Lake has been occurring since 1992, going from a eutrophic system dominated by algal growth to a moderately clear mesotrophic system.

Most of the Minneapolis Lakes have no directional trend in water quality indicators since the early 1990s. The water quality in Cedar Lake showed improvement following restoration efforts through the late 1990s but has shown a slow decline since; however, current TSI scores are still below levels in the early 1990s. Lake Harriet experienced a few years with lower TSI scores following a littoral

2015 Water Resources Report – Minneapolis Park & Recreation Board Page 18-4 alum treatment in the mid-2000s, but has returned to values similar to the 1990s and remains stable. Lake Hiawatha is heavily influenced by the inflow from Minnehaha Creek. The TSI scores in Lake Hiawatha have remained stable over the past 24 years, but the lake has poorer water quality during drought years. The water quality in Lake of the Isles varies from year to year, but there is no significant trend in any direction since 1991. Loring Pond experienced decreased water quality immediately following a dredging project in 1997; however, conditions have slowly returned to levels similar to pre-1997. Powderhorn Lake has experienced large swings in water quality, with the worst TSI scores in the late 1990s and the best scores in the late 2000s. Powderhorn currently has a recent trend towards worse water quality in the past six years. The water quality in Spring Lake is variable, but there is no significant trend in any direction since 1994.

Diamond Lake and Grass Lake are not included in this analysis, since TSI scores are only appropriate for deeper lake systems and there is no water clarity measurements available in these lakes. There are no lakes in Minneapolis with significant decreases in water quality indicators since the early 1990s (linear regression, p < 0.1).

2015 Water Resources Report – Minneapolis Park & Recreation Board Page 18-5

Figure 18-2. TSI scores for selected Minneapolis lakes 1991–2015.

2015 Water Resources Report – Minneapolis Park & Recreation Board Page 18-6 LAKE LEVELS

Lake levels are recorded weekly for Harriet, Hiawatha, Nookomis, Loring, Powderhorn, Wirth, and the Upper Chain of Lakes (Brownie, Calhoun, Cedar and Islees) at Lake Calhoun from ice-out to ice-on. Channels connect the Upper Chain of Lakes which makes the level at Calhoun representative of all four lakes. Fixed staff gauges are used at all locations that are shown in Figure 18-3. Average annual lake levels and selected statistics for each lake with a staff gauge are shown in Tables 18-4 and 18-5. Water levels for Minneapolis lakes are illustrated in Figure 18-4.

Figure 18-3. Minneapolis lake level monitoring locations.

2015 Water Resources Report – Minneapolis Park & Recreation Board Page 18-7

Lake levels vary annually based on precipitation, stream flow, and stormwater inflow. The spring of 2015 started out dry, with below average precipitation through April. There was above average precipitation from May through July, with July having over 3 inches of rain above normal. The weather dried up again in August before a wet fall. The above average rain from May through July caused lake levels to rise throughout the city. Water levels then slowly fell over the remainder of 2015. Only Powderhorn and Nokomis greatly varied from 10-year averages. All other lakes were similar to their long term average lake level as can be seen in Tables 18-4 and 18-5. Historical lake levels can be found in the individual lake chapters

Loring’s water level was allowed to fall below the outlet in 2014 to allow cattails to be cut at the manipulated water surface. Water levels were then augmented with groundwater in November 2014, flooding the cut shoots and preventing oxygen from reaching the rhizomes and thus killing the plant. Groundwater continued to be pumped into Loring Pond throughout 2015 to keep water levels at the top of the outlet structure. Large storms have caused stormsewers to surcharge to the pond periodically in the last 10 years and can be seen in the lake level graph in Loring’s individual lake chapter.

Powderhorn Lake is another lake that can be augmented by a groundwater well; however, the augmentation well was only used in April. In the fall the outlet pump was turned on and 9.9 million gallons were pumped out of the lake to accommodate work on the Tea House. The lake is strongly influenced by stormwater. Large storms are often followed by peaks in Powderhorn’s level. The lake was 1.68 feet above its 10-year average in 2015 (Table 18-5).

Lake Hiawatha levels are influenced by the inflow of Minnehaha Creek which changes depending on the operation of the Lake Minnetonka outlet dam. The dam at Gray’s Bay opened in May 2015 and was only open between 12-20 cfs from May through October. The dam periodically closed in October before needed to be opened to 100-300 cfs in November. The dam remained open above 75 cfs until the end of December. The 2015 average lake level was 0.13 feet below the 10-year average for the lake.

Table 18-4. Average annual lake levels in feet above msl for the past 10 years.

Lake 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015 Chain§ 852.85 852.53 852.14 851.75 852.50 852.94 852.05 852.66 853.80 852.38 Harriet 847.11 847.37 847.13 846.89 847.28 847.63 847.14 847.48 847.84 847.36 Diamond 820.91 NA NA 821.59 822.02 821.84 821.58 821.72 822.24 822.35 Hiawatha 812.61 812.31 812.14 811.64 812.79 813.36 811.83 813.05 814.14 812.53 Loring* 816.68 817.63 817.85 817.80 817.77 817.84 817.95 817.85 814.87 818.45 Nokomis 812.96 813.00 813.22 811.89 812.24 814.71 814.46 815.13 816.37 815.24 Powderhorn* 818.40 817.43 816.89 816.70 817.18 817.76 817.39 818.15 819.67 819.60 Wirth 817.81 817.95 817.96 817.95 818.03 818.07 818.00 818.10 818.47 818.27 § The Chain of lakes includes: Calhoun, Cedar, Isles, & Brownie. * In dry years the level can be below recordable stage.

2015 Water Resources Report – Minneapolis Park & Recreation Board Page 18-8 Table 18-5. Selected statistics for lakes with level data based on the past 10 years of data.

Standard deviation 10 year average 2015 average 2015 comparison Lake around 10 year average (ft msl) (ft msl) to 10 year average (ft) (ft) Chain 852.67 852.38 -0.29 0.84 Harriet 847.37 847.36 -0.01 0.43 Hiawatha 812.66 812.53 -0.13 1.15 Loring 818.06 818.45 0.39 0.34 Nokomis 814.22 815.24 1.02 1.55 Powderhorn 817.92 819.60 1.68 1.25 Wirth 818.09 818.27 0.18 0.29

Figure 18-4. Lake levels for the Minneapolis Lakes in 2015. Horizontal lines represent ordinary high water elevation (OHW). Note the MDNR has not designated an OHW for Powderhorn Lake.

2015 Water Resources Report – Minneapolis Park & Recreation Board Page 18-9 LAKE AESTHETIC AND USER RECREATION INDEX (LAURI)

The LAURI was developed to provide recreational users with an additional source of information about the health of MPRB lakes. The LAURI provides lake users with an easily understandable recreational suitability indicator for the MPRB lakes. Background information on the LAURI can be found in Section 1. The LAURI index was updated in 2009 to include measures of habitat quality and recreational access, and has been used by Minneapolis and the Minneapolis Greenprint as a Citywide Metric.

All scores in the LAURI are between 1 and 10 with 10 as the best possible score. Table 18-6 shows the LAURI scores of each lake for 2015. If the LAURI parameters were looked at for all of the lakes together, it would look like the LAURI presented in Figure 18-5.

Table 18-6. 2015 sub-scores and classifications for each LAURI category.

Water Public Health Habitat Recreation Lake Aesthetics Clarity Index Quality Access Calhoun 8.9 7.0 6.0 9.0 10.0 Cedar 9.0 4.0 7.0 8.3 10.0 Harriet 8.6 6.0 8.0 8.5 10.0 Hiawatha* 7.1 8.0 1 6.3 4.0 Isles* 9.1 8.0 N/A 7.5 10.0 Loring* 8.7 10.0 N/A 3.5 3.0 Nokomis* 8.9 6.0 7.0 4.8 10.0 Powderhorn* 7.0 2 N/A 5.3 3.0 Wirth 9.0 6.0 8.0 6.8 10.0

LEGEND Excellent Good Poor * Denotes shallow lake. NB = no swimming beach.

In general, lakes with the best habitat quality also had the best clarity and aesthetics. Lakes with poor clarity, odor, or trash problems scored lower in aesthetics. Larger lakes had better recreational access scores due to more opportunities to access the water through boating.

2015 Water Resources Report – Minneapolis Park & Recreation Board Page 18-10

Figure 18-5. 2015 Average LAURI for Minneapolis. Includes: Callhoun, Cedarr, Harriet, Hiawatha, Isles, Loring, Nokomis, Powderhorn, and Wirth Lakes.

WINTER ICE COVER

The Minneapolis lakes had a longer than average ice-free period in 2015. Ice came off the lakes around 5-10 days earlier than the average ice-off date and varied based on lake size, as shown in Table 18-7. Most lakes completely froze over between a week and two weeks earlier than the average recorded ice-on date, as can be seen from Table 18-8. Lake size typically influences the date ice forms on the lakes, with the larger lakes freezing later than some of the smaller lakes in Minneapolis. For further information on winter ice coverr records see Section 1 and individual lake sections.

2015 Water Resources Report – Minneapolis Park & Recreation Board Page 18-111 Table 18-7. Statistics related to ice-off dates.

Earliest Year Latest Year Years of Lake 2015 Ice Off Occurred Ice Off Occurred Mean Median Record Birch 3/30 3/8 2000 4/28 2013 4/4 4/4 30 Brownie 3/31 3/9 2000 4/28 2013 4/4 4/3 34 Calhoun 4/2 3/9 2000 4/28 1965, 2013 4/9 4/10 66 Cedar 4/1 3/9 2000 4/28 2013 4/7 4/6 42 Diamond 3/21 3/6 2000 4/24 2013 4/1 4/4 23 Harriet 4/2 3/9 2000 4/28 1965, 2013 4/7 4/7 48 Hiawatha 3/29 3/8 2000 4/26 2013 4/4 4/4 41 Isles 3/30 3/8 2000 4/28 2013 4/5 4/5 46 Loring 3/23 3/6 2000 4/25 2013 4/2 4/3 35 Nokomis 3/26 3/8 2000 4/27 2013 4/5 4/4 44 Powderhorn 3/25 3/8 2000 4/27 1965, 2013 4/4 4/3 36 Spring 3/23 3/6 2000 4/24 2013 4/1 4/2 25 Wirth 3/26 3/7 2000 4/27 2013 4/2 4/3 39

Table 18-8. Statistics related to ice-on dates.

Earliest Year Latest Years of Lake 2015 Ice On Occurred Ice On Year Occurred Mean Median Record Birch 11/30 11/1 1991 12/16 1998 11/25 11/27 30 Brownie 12/21 11/5 1991 12/21 2015 11/29 12/1 34 Calhoun 1/4 11/25 1996 1/16 2006-07 12/12 12/10 46 12/21 11/18 1989 12/21 1998, 1999, 12/4 12/4 34 Cedar 2001, 2015 Diamond 12/18 11/13 2008, 2014 12/20 2001 12/1 12/1 21 Harriet 1/4 11/25 1996 1/16 2006-7 12/13 12/11 43 Hiawatha 12/28 11/1 1991 1/31 2006-7 12/3 12/3 35 Isles 12/21 11/5 1991 1/2 2006-7 12/1 12/2 41 12/21 11/1 1991 12/21 1999, 2001, 12/1 12/3 31 Loring 2015 Nokomis 12/28 11/1 1991 1/17 2011-12 12/1 12/1 36 Powderhorn 12/21 11/1 1991 12/21 2001, 2015 11/29 11/30 31 Spring 12/18 11/10 1995 12/20 2001 11/28 11/27 25 Wirth 12/21 11/5 1991 12/21 2001, 2015 11/30 12/2 35

2015 Water Resources Report – Minneapolis Park & Recreation Board Page 18-12 INVASIVE SPECIES MONITORING

MPRB has been actively monitoring invasive species since the late-1980s, when Eurasian watermilfoil (Myriophyllum spicatum) was first discovered in the Chain of Lakes. By 1992, MPRB and the Hennepin County Conservation District began managing milfoil in the Chain of Lakes with financial support from the MDNR. In the early 1990s, MPRB staff tracked areas of invasive Eurasian watermilfoil (EWM) versus native northern watermilfoil (Myriophyllum exalbescens). Later, MPRB partnered with Dr. Ray Newman of the University of Minnesota. Dr. Newman conducted some early studies in the Minneapolis lakes and the potential use of a native beetle, Euhrychiopsis lecontei, that prefers to feed on EWM and can be grow to high enough densities to diminish the growth of EWM in lakes in certain situations.

MPRB first began managing aquatic invasive species when Eurasian water milfoil was discovered; however, EWM was not the first invasive aquatic species to be introduced to the MPRB lakes. In 1910, curly-leaf pondweed (Potamogeton crispus) was first documented in the state of Minnesota. Curly-leaf pondweed has an unusual life cycle in that it is an annual that begins growing under the ice and dies off in June. After mild winters, curly-leaf pondweed often produces thick mats of vegetation in the spring that is a nuisance for boating; however, this plant can be held to low levels of growth by harsh Minnesota winters. Macrophyte surveys by Shapiro (1974) documented curly-leaf pondweed in Lakes Calhoun, Harriet, Isles, and Nokomis. The surveys carried out by Shapiro were in late-July which was likely too late in the season to capture the full extent of curly-leaf pondweed in the Minneapolis Lakes.

The 1974 Shapiro surveys found that aquatic plants grew to only about 15 feet of depth in Lakes Calhoun and Harriet. Lake of the Isles and Lake Nokomis only had plants growing out to about 5 to 6 feet of water. Wirth Lake only had a shallow ring of aquatic plants growing out to a depth of 3 feet. Intact and robust native plant communities are better able to withstand invasion by exotics. Therefore, the lack of plant growth throughout the littoral zones of the Minneapolis lakes may have left them vulnerable to invasion by EWM two decades later.

Most other exotic aquatic species only occur in a few lakes in the MPRB system as can be seen from Figure 18-6 and Table 18-9. Brazilian water weed (Egeria densa) was found in Powderhorn Lake in 2007 during a routine MPRB plant survey. The MDNR mapped areas where the invasive plant was growing and chemically treated those areas with diquat, an herbicide approved for aquatic use. Brazilian water weed has not been identified in the lake since treatment. This plant can grow to extremely high densities limiting growth for native plants. It is a common aquarium plant and likely found its way to Powderhorn Lake via an aquarium release. Powderhorn was delisted for Brazilian water weed in 2014 after five years of surveys not finding the plant.

Chinese mystery snails (Bellamya chinensis) have been identified by MDNR and MPRB in Loring Pond, Powderhorn Lake, and Grass Lake as shown in Figure 18-6 and Table 18-9. The Chinese mystery snail, which is native to Asia, was introduced to California in 1892 and was found on the East Coast by 1915 (MDNR, AIS website). The species is a popular aquarium snail and new populations are often a result of an aquarium release. This species has the capability of growing to high densities and tends to have boom and bust cycles. When the population reaches the “bust” portion of the cycle, large concentrations of dead snails can ring the shoreline and create odor and aesthetic issues as they decompose.

2015 Water Resources Report – Minneapolis Park & Recreation Board Page 18-13 Lakes Nokomis and Hiawatha have been declared infested with zebra mussels (Dreissena polymorpha) because of their connection with Minnehaha Creek and Lake Minnetonka. However, as of fall 2015, zebra mussels have not been confirmed to be present in Lake Nokomis. The Minnehaha Creek Watershed District (MCWD) and MPRB have performed rapid assessments on MPRB lakes each fall since zebra mussels were confirmed in Lake Minnetonka in 2010. MPRB also deploys bi- monthly samplers in Calhoun, Harriet, and Hiawatha as an early detection method. Additionally, Friends of Lake Nokomis monitors two bi-monthly samplers in Lake Nokomis. In August 2013, zebra mussels were confirmed as present in Lake Hiawatha. Zebra mussels were found on the sampling plate in Hiawatha again in the fall of 2015. No zebra mussels were found in the other Minneapolis lakes via MPRB and MCWD’s rapid assessments or zebra mussel sampling program in 2015.

Lakes containing European carp (Cyprinus carpio) and goldfish (Carassius auratus) are identified in Figure 18-6. The data shown were taken from MDNR Lake Finder and is based on MDNR fish surveys. Other Minneapolis lakes may have carp or goldfish but these species have not been identified specifically in fish surveys. Each of these species can reproduce to very high densities. At high densities, these bottom-feeding fish are capable of disturbing lake beds to the extent that water quality can be diminished. Lakes with an overgrowth of European carp typically have high phosphorus concentrations, low water clarity, and little to no aquatic plant growth. Carp eat vegetation and can alter or destroy the aquatic plant community in a lake. In 1977, MDNR chemically treated Wirth Lake with rotenone to remove rough fish and stocked the lake with largemouth bass, walleye, and channel catfish. In 2002, the MCWD sponsored a carp removal at Lake Nokomis.

Zebra Mussels European Carp Goldfish Brazilian Waterweed Chinese Mystery Snail Eurasian Watermilfoil Curly Leaf Pondweed 5

4

3

2

1

0

Figure 18-6. Invasive and exotic aquatic species found in MPRB Lakes. Birch Pond, Ryan, and Grass Lakes have not been fully surveyed for invasive species. Zebra mussels have not been confirmed present in Lake Nokomis. Brazilian water weed in Powderhorn was successfully treated with chemicals in 2007.

2015 Water Resources Report – Minneapolis Park & Recreation Board Page 18-14

Table 18-9. Exotic species established in MPRB lakes, the number of lakes where the species are found and the data source used. Common Name Scientific Name # of Lakes Data Source Curly leaf pondweed Potamogeton crispus 11 MPRB Eurasian watermilfoil Myriophyllum spicatum 10 MDNR infested waters list European carp Cyprinus carpio 8 MDNR fish survey Chinese mystery snail Bellamya chinensis 3 MDNR Zebra mussel§ Dreissena polymorpha 2 MDNR infested waters list Goldfish Carassius auratus 2 MDNR fish survey Brazilian water weed* Egeria densa 0 MDNR infested waters list §Lakes Nokomis is considered infested with zebra mussels due to its connection with Minnehaha Creek and Lake Minnetonka. The species has not been confirmed present in Lake Nokomis as of fall 2014. * Treated successfully in 2007 by MDNR and delisted in 2014.

2015 Water Resources Report – Minneapolis Park & Recreation Board Page 18-15 19. PUBLIC BEACH MONITORING

BACKGROUND

The Minneapolis Park and Recreation Board (MPRB) has twelve official beaches located on six lakes (Figure 19-1). Prior to 2003 the City of Minneapolis Environmental Health Department monitored the beaches for fecal coliform bacteria. The MPRB began beach monitoring in 2003 and tested the beaches for Escherichia coli (E. coli) as well as fecal coliform bacteria. From 2004 to the present MPRB Environmental Management staff monitored the beaches for E. coli alone as recommended by the US Environmental Protection Agency (US EPA). US EPA guidelines for E. coli require that a single sample should not exceed 235 organisms per 100 mL of water and that the geometric mean of not less than 5 samples equally spaced over a 30-day period should not exceed 126 organisms per 100 mL of water (US EPA, 1986). MPRB followed this set of guidelines for the 2004 and 2005 beach seasons. Epidemiological testing allowed the Minnesota Pollution Control Agency to develop an inland lakes standard which MPRB has followed since 2006. The inland lakes standard has a single- sample limit of 1,260 organisms per 100 mL and was accepted into rule during 2008 and has been used by MPRB since that time.

Figure 19-1. Map MPRB public beaches monitored in 2015.

2015 Water Resources Report – Minneapolis Park & Recreation Board Page 19-1 A great diversity of pathogenic microorganisms exist, and testing for a large array of microbes would be time consuming and expensive. Due to this difficulty, E. coli is used as an indicator organism for monitoring and regulation. E. coli is a proxy for the measure of fecal contamination in recreational waters (US EPA, 2005). Indicator organisms do not cause illness under normal conditions which makes them useful when determining if a potential health risk is present in the lake water. Bacteria can enter the aquatic environment from agricultural and stormwater runoff, direct discharge of waste from mammals and birds and from untreated human sewage. Elevated bacteria levels generally occur in aquatic environments after rain events when bacteria from various sources are washed into the lakes. Elevated bacteria levels in MPRB lakes usually return to normal levels within 24 to 48 hours of a rain event.

Potential sources of E. coli in lake water include:  foreshore beach sand  organic debris  leaking diapers, bather defecation  polluted stormwater runoff  sewage spills near the beach  sewer line break discharges  stream inflows  wild and domestic animal waste (such as geese, gulls, raccoons, dogs, etc.).

Research originally used to develop E. coli as an indicator organism held that it does not survive well outside of the digestive systems of warm-blooded animals. Half-lives of approximately 1 day in water, 1.5 days in sediment, and 3 days in soil were once thought to be typical survival rates of E. coli outside of its host environment (Winfield and Groisman, 2003).

More recent findings indicate that E. coli is able to survive and grow outside of its host environment. New research shows that algae can be a potential source of E. coli. Whitman et al. (2003) found that Cladophora (green algae) mats in Lake Michigan are capable of supporting E. coli in significant numbers. Bacteria from the dried mats grew upon re-hydration even after 6 months. Shigella, Salmonella, Campylobacter, and a shiga toxin-producing strain of E. coli (STEC) have also been found to be associated with a common filamentous algae species, Cladophora (Byappanahalli et al, 2008).

Beach sand has also been identified as another potential growth medium for E. coli. Whitman and Nevers (2003) have shown that E. coli can sustain itself in wet beach sand that can serve as a non- point source of bacterial contamination. Another study by Byappanahalli et al. (2003) found E. coli to be ubiquitous and persistent in a Midwestern stream. E. coli was common in stream banks and wetted sediments acting as a source of contamination to the stream. Genthner et al. (2005) found that after tidal events the swash zone (area of beach where waves continuously wash up on the sand) harbored higher densities of microorganisms and indicator bacteria, which is partially attributable to entrapment. It has been shown that biological (e.g. nutrients and protection from predation) and physical (e.g. particulate matter, periodic wetting and drying, and protection from solar irradiation) factors enhance bacteria survival while providing a growth-promoting environmental niche. In studies in the Upper Midwest, Ishii et al. (2005) found significant populations of viable, naturalized E. coli in northern temperate soils in three Lake Superior watersheds. Ishii et al. (2007) found that the distribution of human and naturalized sources of E. coli at beaches can change over the course of a summer.

2015 Water Resources Report – Minneapolis Park & Recreation Board Page 19-2 METHODS

Samples were collected from twelve MPRB beaches every Monday during the beach season (6/8/15 through 8/31/15). Beaches monitored in the 2015 MPRB program were:

 Calhoun 32nd Street  Calhoun Main (North)  Calhoun Thomas (South)  Cedar Main (South)  Cedar Point  East Cedar (Hidden)  Harriet Main  Harriet Southeast  Hiawatha  Nokomis 50th Street (East)  Nokomis Main  Wirth Main.

Two E. coli samples and one Enterococci sample were taken from each beach in knee deep water (1.8 feet) roughly six to twelve inches below the surface. The samples were then transported in an ice water bath to Instrumental Research Incorporated’s lab (IRI). IRI used a Colilert-Quanti Tray to determine the most probable number (mpn) of E. coli and Enterococci colonies in the samples. Field duplicates were also collected every sampling day on a rotating schedule. Water and air temperature were measured using a digital thermometer. Rain data was collected at the MPRB South Side Service Center using a tipping bucket rain gage.

Other parameters collected in the field when samples were taken included:  air temperature  current weather  LAURI parameters of beach (For additional information on the LAURI see Section 1)  number of adults, children, and children in diapers not in the water broken  number of geese, ducks, and gulls on the beach  number of swimmers in the water broken down by adults, children, and children in diapers  water quality parameters (when permitted)  water temperature  comments (anything unusual, visible fecal material).

Additional data compiled in the office were:  amount of previous day’s rainfall  wind speed and direction  duration of rain event  hours since last rain event  intensity of rain event  lake level  beach attendance.

2015 Water Resources Report – Minneapolis Park & Recreation Board Page 19-3 RESULTS & DISCUSSION

Specific lake and beach results are discussed in each of the lake sections.

Table 19-1 shows the basic descriptive statistics of E. coli (mpn organisms per 100 mL of water) in the beach water sampled during the 2015 beach season. Most beaches had low season-long geometric means, but there were couple beach closures during the 2015 beach season. Thomas Beach on Lake Calhoun closed on 6/30/15 due to the single sample limit of 1,260 E. coli per 100 mL of water being exceeded and reopened once samples showed E. coli had returned to acceptable levels on 7/1/15. The presence of significant amounts of waterfowl waste was observed at the beach during the closure, and may have contributed to the observance of high E. coli. Lake Hiawatha’s beach closed on 7/8/15 due to high a geometric mean that exceeded the 126 mpn/100 mL standard and remained closed the remainder of the season.

Table 19-1. Minimum, maximum, median, mean, geometric mean (entire season), and maximum 30-day geometric mean for E. coli values (mpn/100 mL) from the twelve beaches monitored by the MPRB in 2015.

Statistical Calhoun Calhoun Calhoun Cedar Cedar Cedar Harriet Harriet Hiawatha Nokomis Nokomis Wirth Calculations 32nd Main Thomas East Main Point Main SE 50th Main

Number of 13 13 13 13 13 13 13 13 13 13 13 13 Samples Minimum 7 3 3 1 4 2 4 1 12 8 9 2 Maximum 353 207 1484 150 155 158 129 243 2420 100 78 586 Median 50 15 56 10 31 60 12 36 355 26 37 10 Mean 107 57 265 32 43 59 21 62 728 39 37 85 Geometric 60 21 59 10 29 30 13 26 280 27 29 16 Mean Max 30-Day 120 56 101 28 51 86 22 85 506 59 60 69 Geo Mean Standard 112 77 455 47 42 45 33 70 882 33 23 179 Deviation

In general, rain and large amounts of birds near the beach are likely the single most influential cause of elevated E. coli levels in Minneapolis lakes. Rain washes the bacteria off of hard surfaces and sends it through the storm sewer system to the lakes. Table 19-2 shows the number of storms during the beach season, the amount of rain received in the largest single rain event, the average amount of precipitation per rain event, and the total amount of rain received during the beach season. Rain data was collected at the MPRB South Side Service Center Rain gauge.

The relationship between rain and E coli at the beaches is complex. Differences in the timing and pattern of rainfall may be more influential on E. coli levels than rainfall amounts. The combination of rain intensity and duration may also influence bacteria at some of the beaches.

2015 Water Resources Report – Minneapolis Park & Recreation Board Page 19-4 Table 19-2. Number of storms, largest storm (inches), average storm (inches), and total rain (inches), for the 2009–2015 beach seasons. A storm is defined as being greater than 0.10 inches and separated by 8 hours.

2009 2010 2011 2012 2013 2014 2015 Number of storms 11 20 15 16 12 15 18 Max rain single event 2.27 2.52 3.71 0.85 3.0 3.0 2.52 Avg rain per event 0.64 0.62 0.91 0.42 0.8 0.66 0.69 Total Rain 7.02 12.49 13.81 6.7 9.66 10.15 12.22

It is difficult to assess the quality of water the same day of sample collection since testing requires 24 hours. The lag time between sample collection and receipt of test results can result in unnecessary beach closures and/or exposure to poor water quality. A study by Ha Kim and Grant (2004) found that the public is misnotified about current water quality status and beaches are misposted up to 40% of the time. An example of this at MPRB occurred in 2015 when a sample was taken at Calhoun Thomas Beach on June 29th. The beach was closed around noon on the 30th when the results were found to exceed the single sample limit and the beach was re-sampled. The results from that sample came back on July 1st and were below the limit. The beach was open on June 29th when it should have been closed and closed unnecessarily on June 30th when it should have been open. The 24-hour delay caused posting errors on 2 days.

Beach management decisions are made using the best available methods and data. MPRB Environmental Stewardship staff seeks out the latest E. coli and beach pathogen research as well as technology for a rapid E. coli test to eliminate unnecessary closures. In the past, staff members have also participated in a Metro-Wide Beach Regulators group to enhance consistency among the different organizations operating beaches in the Metro.

In the US EPA Environmental Health Perspective (2005), the number of illnesses attributable to recreational water exposures was reported to be increasing. In Minnesota, there were 11reported outbreaks which were traced to recreational contact at lakes since 2005. The outbreaks were associated with 6 different pathogens (Minnesota Department of Health, 2015). It should be noted that none of the waterborne illness outbreaks were at Minneapolis beaches.

Communicating the results of beach monitoring with the public is a very important aspect of the process and also offers an opportunity for water and public health education. A phone and email tree is utilized to quickly notify staff and elected officials of beach closures and re-openings. A Beach Information Telephone Line (612.313.7713) is updated daily on beach closures due to bacteria testing. Results from testing are also put on the MPRB website the day results are received (https://www.minneapolisparks.org/park_care__improvements/water_resources/beach_water_resourc es/). The communication efforts were very successful in 2015 and offered the public many opportunities to obtain information regarding beach water quality and closures.

2015 Water Resources Report – Minneapolis Park & Recreation Board Page 19-5 In addition to monitoring E. coli at the beaches, MPRB collected enterococci samples during 2015 to help understand enterococci concentrations being taken at Webber Natural Swimming Pool (NSP). The enterococci and E. coli concentrations were correlated with each other (Spearman’s correlation, p < 0.05), but there were a few high enterococci samples where E. coli was low (Figure 19-2). The strong correlation between the two isn’t too surprising as both are indicators of fecal contamination. Enterococci is the preferred indicator in oceanic beaches rather than E. coli; however, the two indicators cannot be used interchangeably in freshwater monitoring (Kinzelman et al, 2002). This knowledge, along with the natural range of enterococci, helps interpret data taken from Webber NSP (Section 19).

Figure 19-2. E. coli vs. enterococci concentrations (MPN per 100 mL) taken from the Minneapolis beaches in 2015. Diagonal line is a 1:1 line representing perfect correlation. Note: Both axes are on a log scale.

2015 Water Resources Report – Minneapolis Park & Recreation Board Page 19-6 20. AQUATIC PLANT MANAGEMENT

EURASIAN WATER MILFOIL (MYRIOPHYLLUM SPICATUM)

Eurasian watermilfoil (Myriophyllum spicatum) has been an ongoing concern in several Minneapolis lakes. From an ecological standpoint it out-competes native species and changes the habitat for fish and other organisms. Milfoil often forms dense floating mats that interfere with boating and swimming.

The Minneapolis Park and Recreation Board (MPRB) primarily uses harvesting to maintain recreational access to city lakes. Only the top two meters of the milfoil plants are removed and this temporarily allows for problem-free boating and swimming. The MDNR permits limit the area of milfoil harvest. Harvesting was completed on Calhoun, Cedar, Harriet and Isles in 2015. MPRB Staff removed 211 flatbed truck loads of milfoil in 2015 which is comparable to 1158 cubic yards of aquatic plant material. For harvested acreage see each individual lake section. MPRB contracted out harvesting work on Wirth and Nokomis to Waterfront Restoration, LLC, who removed milfoil from high traffic recreational areas by hand via SCUBA.

In the early 2000s, the MPRB and the University of Minnesota released aquatic weevils that eat Eurasian water milfoil into Cedar Lake, Lake of the Isles, Lake Harriet, and Lake Hiawatha. The weevils were not successful controlling milfoil. The most likely explanation is that the high density of sunfish in the lakes fed on the weevils and limited their population. In 2015, the University of Minnesota continued to research the effect of sunfish on weevil densities in Cedar Lake.

BRAZILIAN WATERWEED (EGERIA DENSA)

In August of 2007, the aquatic invasive species Egeria densa (E. densa) was identified in Powderhorn Lake. The new invasive is native to South America and used extensively in aquariums and water gardens. It is likely that Egeria was introduced to Powderhorn Lake though an aquarium release. In September of 2007, the MDNR spot-treated stands of E. densa with diquat, an herbicide approved for aquatic use. The lake was removed from the list of waterbodies infested with this plant in 2014 following five years of MDNR and MPRB surveys not finding E. densa in Powderhorn.

PURPLE LOOSESTRIFE (LYTHRUM SALICARIA)

Since 1999, the MPRB has collaborated with the MDNR to introduce leaf-feeding beetles (Galerucella spp.) as a biocontrol for purple loosestrife (Lythrum salicaria). Both biocontrol methods and chemical herbicides are used to manage purple loosestrife throughout the park system. Beetles were found feeding at major purple loosestrife sites on MPRB properties in 2013. MPRB and MDNR staff continue to monitor beetle release sites. Additionally, MPRB leads a volunteer effort to cut purple loosestrife inflorescence around Lake of the Isles in order to limit seed dispersal. In 2015, 121 hours were spent clipping purple loosestrife and was the fourth year of volunteer management efforts around the lake. MPRB has tracked the spread of purple loosestrife around Lake of the Isles to monitor its spread and efforts to limit seed dispersal.

2015 Water Resources Report – Minneapolis Park & Recreation Board Page 20-1 21. Wetland Health Evaluation Project (WHEP)

BACKGROUND

The Wetland Health Evaluation Project (WHEP) began in 1997 in Dakota County with Environmental Protection Agency (US EPA) funding. In 2001, Hennepin County began its own WHEP program as a pilot project. The pilot program was successful at both the county and local levels and has continued as a partnership between the two counties, cities, and other water management organizations. WHEP utilizes teams of trained volunteers to collect and analyze wetland data to characterize wetland health. Hennepin County Environmental Services staff then cross-check, synthesize, and report the collected data back to the partner organizations and to the public.

MPRB has sponsored citizen volunteer teams who monitor wetlands within the park system each year since 2002. Every summer between two and six wetlands are monitored within Minneapolis depending on the needs of the MPRB. During 2015 the wetlands monitored were: a portion of the wetland edge of Diamond Lake, Heritage Park North Wetland, Wirth Beach Restored Wetland, Southwest Calhoun and Amelia Pond. The Roberts Bird Sanctuary wetland is also monitored annually as a reference wetland site for the City of Minneapolis.

For more information see the Minnesota WHEP website at www.mnwhep.org.

METHODS

Volunteers for the project are trained in three sessions by MPCA staff. Training sessions cover monitoring methods, macroinvertebrate identification, and vegetation identification. Spot checks and quality control checks are conducted by other citizen teams and by a technical expert for quality assurance purposes.

Sampling from the wetlands includes both vegetation and invertebrate data. All wetland evaluation and sampling protocols followed the Vegetation Method for Wetland Evaluation (Gernes, 2002). A vegetation survey was performed in a 100 square meter plot considered representative of the entire wetland for each site. Additionally, an invertebrate survey was completed with two samples from a dip-net within the emergent vegetation zone, near the shoreline, and in six overnight bottle trap samples.

The information is then used to evaluate the wetland’s biological health based on metrics developed by the Minnesota Pollution Control Agency (MPCA). An index of biotic integrity (IBI) has been developed by the MPCA to include both vegetation and invertebrate metrics. The IBI metrics are listed below.

2015 Water Resources Report – Minneapolis Park & Recreation Board Page 21-1 Vegetation IBI metrics (identification to genus level)  Total number of forbs, woody species, and grass-like plants  Total number of mosses, lichens, liverworts, and macro-algae (Chara and Nitella)  Cover of sedge (Carex)  Presence of Bladderwort (Ultricularia)  Total number of “Aquatic Guild” plants  Cover of plants with persistent standing litter

Invertebrate IBI Metrics (identification to family level)  Number and type of leeches in net and bottle trap samples  Proportion of Water Boatmen (Corixidae) in a bottle trap in relation to the total number of aquatic beetles and all bugs in the sample  Number of types of dragonflies and damselfly nymphs in dip-net samples  Total number of mayflies, plus the number and type of caddis flies, plus presence of fingernail clams and dragonflies  Number of types of snails  Number of taxa above, plus the number of crustaceans, plus the presence of Chaoborus

Ratings developed for the invertebrate and vegetation IBI are shown below in Table 21-1. The IBI assessment is useful to give a wetland a qualitative description that makes it easier to communicate results. Wetlands with poor ratings would have minimal species richness and diversity indicating disturbance and poor wetland health. A wetland with a rating of excellent would have high diversity and species richness indicating a healthy wetland and relatively minimal ecological disturbance.

Table 21-1. Ratings for the invertebrate and vegetation IBIs.

Invertebrate Index of Biotic Integrity Vegetation Index of Biotic Integrity Sum of invertebrate Sum of vegetation Interpretation Interpretation metric scores metric scores 6-14 Poor 7-15 Poor 15-22 Moderate 16-25 Moderate 23-30 Excellent 26-35 Excellent

RESULTS AND DISCUSSION

During the summer of 2015, WHEP-trained volunteers monitored six wetlands within the MPRB system. Roberts Bird Sanctuary was monitored for its thirteenth time serving as a reference wetland for the Minneapolis WHEP program. IBI scores for other monitored wetlands can be compared to scores for the reference wetland to determine the effects of inter-annual variation or regional changes (drought, wet periods, plant diseases, etc.) on wetland heath. Results and discussion for each wetland are presented individually within this section.

Roberts Bird Sanctuary (Reference Site) The Roberts Bird Sanctuary is located north of Lake Harriet. The Sanctuary is a natural area that has been preserved, and thus has been used as a reference wetland for the Minneapolis WHEP program. The wetland is estimated to be ten acres in size. The WHEP team accesses the monitoring location near a tamarack stand from the boardwalk. 2015 was the thirteenth year that WHEP monitored the site. Table 21-2 shows the results for Roberts Bird Sanctuary. In 2015, the wetland scored 22/moderate for invertebrates and 21/moderate for vegetation.

2015 Water Resources Report – Minneapolis Park & Recreation Board Page 21-2 Table 21-2. WHEP scores at the Roberts Bird Sanctuary Site.

Invertebrate Invertebrate Quality Vegetation Quality Year Vegetation Score Score Rating Rating 2003 20 Moderate 17 Moderate 2004 20 Moderate 17 Moderate 2005 22 Moderate 15 Poor 2006 22 Moderate 17 Moderate 2007 28 Excellent 13 Poor 2008 20/22 Moderate/Moderate 21/17 Moderate/Moderate 2009 26 Excellent 19 Moderate 2010 20/22 Moderate/Moderate 21/19 Moderate/Moderate 2011 22/23 Moderate/Moderate 21/23 Moderate/Moderate 2012 26 Excellent 11 Poor 2013 24 Excellent 15 Poor 2014 26 Excellent 15 Poor 2015 22 Moderate 21 Moderate

Diamond Lake Wetland Fringe Diamond Lake has been monitored eleven times in the WHEP Program. The wetland fringe at Diamond Lake has typically scored poor in vegetation IBI and the invertebrate IBI has varied (Table 21-3). In 2015, the Diamond Lake Wetland Fringe was cross checked by two teams and scored 18/moderate and 16/moderate for invertebrates and 19/moderate and 15/poor for vegetation quality. This site is located in an urban setting with a large urban watershed and provides valuable bird habitat.

Table 21-3. WHEP scores at Diamond Lake.

Invertebrate Invertebrate Quality Vegetation Quality Year Vegetation Score Score Rating Rating 2002 8 Poor 13 Poor 2005 14 Poor 7 Poor 2006 16 Moderate 13 Poor 2008 10 Poor 15 Poor 2009 18 Moderate 11 Poor 2010 24 Excellent 20 Moderate 2011 8 Poor 11 Poor 2012 24 Excellent 15 Poor 2013 26 Excellent 15 Poor 2014 19 Moderate 12 Poor 2015 18/16 Moderate/Moderate 19/15 Moderate/Poor

Heritage Park North Wetland Heritage Park North Wetland is located in Sumner Field Park. The wetland was developed in 2006- 2007. It receives stormwater runoff from multiple inlets and outlets at corner of 8th and Aldrich N where water then flows to Bassett Creek Tunnel, under downtown and to Mississippi River. The site was planted with wetland vegetation and infiltration trenches have been re-worked several times

2015 Water Resources Report – Minneapolis Park & Recreation Board Page 21-3 which has disturbed vegetation in the immediate area. The site has many best management practices (BMPs) installed, such as grit chambers and level spreaders, with additional rain gardens upstream.

2015 was the fourth year Heritage Park was included in WHEP monitoring, as presented below in Table 21-4. In 2015, Heritage Park received an invertebrate score of 18/moderate and a vegetation quality score of 23/moderate.

Table 21-4. WHEP scores at Heritage Park North Wetland Invertebrate Invertebrate Quality Vegetation Quality Year Vegetation Score Score Rating Rating 2012 12 Poor 23 Moderate 2013 20 Moderate 23 Moderate 2014 10 Poor 15 Poor 2015 18 Moderate 23 Moderate

Wirth Beach Restored Wetland Wirth Beach Restored Wetland is located near the southern tip of Wirth Lake just southeast of the swimming beach. The site has inlets from the Upper/Lower Wirth wetland complex and parkland and from the basins adjacent to the parking lot to the east of the wetland. The outlet is to Wirth Lake. Additionally, there are multiple groundwater springs at the north end of the wetland. The wetland was historically filled with debris from the old Wirth Beachhouse. Debris was removed and the wetland was replanted. 2015 is the fourth season post-planting. The previous vegetation type of the wetland was a mix of cattail/purple loosestrife.

2015 was the second year of monitoring at the Wirth Beach Restored Wetland, as in Table 21-5. Wirth Beach Restored Wetland received a score of 20/moderate for the invertebrate IBI and a score of 27/excellent for vegetation.

Table 21-5. WHEP scores at Wirth Beach Restored Wetland

Invertebrate Invertebrate Quality Vegetation Quality Year Vegetation Score Score Rating Rating 2014 18 Moderate 25 Moderate 2015 20 Moderate 27 Excellent

Southwest Calhoun Wetland The wetland was constructed in 2000 to treat stormwater prior to discharge into Lake Calhoun. 2015 was the fourth year that the Southwest Calhoun wetland was monitored by WHEP (Table 21-6). The Southwest Calhoun wetland received a score of 14/poor on the invertebrate IBI and a score of 23/moderate on vegetation quality.

Table 21-6. WHEP scores at the Southwest Calhoun Wetland

Invertebrate Invertebrate Quality Vegetation Quality Year Vegetation Score Score Rating Rating 2009 6 Poor 21 Moderate 2010 10 Poor 25 Moderate 2011 14/10 Poor 20/15 Moderate 2015 14 Poor 23 Moderate

2015 Water Resources Report – Minneapolis Park & Recreation Board Page 21-4 Amelia Pond Amelia Pond is located at the S.W. corner of Lake Nokomis. It was once part of a large wetland called “Lake” Amelia. Around 1917 the Minneapolis Park and Recreation Board began dredging Lake Amelia to create what is now called Lake Nokomis. In the 1980s native wetland and wet prairie vegetation was planted in the area, since the location was prone to flooding. In 2001, the Minnehaha Creek Watershed District dredged and created Amelia pond as a stormwater pond to “treat” stormwater runoff entering Lake Nokomis. Plantings of native vegetation were completed the summer of 2001. The site was dredged again in 2010. The summer of 2015 was the fifth time Amelia Pond was monitored through the WHEP Program.

Results have shown improvement in wetland quality since the reconstruction in 2001 (Table 21-7). This wetland was newly reconstructed prior to its first summer in the WHEP program and the wetland has now had several growing seasons to establish and develop increasing diversity and richness. In 2015, the wetland received a 18/moderate score for invertebrates and a 23/moderate for vegetation.

Table 21-7. WHEP scores at Amelia Pond

Invertebrate Invertebrate Quality Vegetation Quality Year Vegetation Score Score Rating Rating 2003 12 Poor 19 Moderate 2004 16 Moderate 23 Moderate 2007 36 Excellent 23 Moderate 2013 21 Moderate 29 Excellent 2015 18 Moderate 23 Moderate

2015 Water Resources Report – Minneapolis Park & Recreation Board Page 21-5 22. NATIONAL POLLUTANT DISCHARGE ELIMINATION SYSTEM (NPDES) MONITORING

BACKGROUND

The Minneapolis Park and Recreation Board (MPRB) and the City of Minneapolis are co-signatories on the National Pollutant Discharge Elimination System (NPDES) Municipal Separate Storm Sewer System (MS4) Permit. The MPRB has performed the NPDES MS4 stormwater monitoring since 2001. Best Management Practices (BMPs) are devices or practices used to treat and clean stormwater. The purpose of the stormwater monitoring is to characterize the quantity and pollutant load of runoff from small areas representing various types of land use under a “no BMP” scenario. In reality, the results do not represent actual conditions for either runoff quantity or quality because there are numerous BMPs and other structural controls and management practices that reduce pollutants in stormwater runoff and/or temper stormwater runoff quantity in the watershed.

At the beginning of the first NPDES MS4 permit (2001-2004), the MPRB and City of Minneapolis partnered with the City of St. Paul to fulfill the NPDES monitoring requirements. Five sites in Minneapolis and St. Paul were jointly monitored between 2001–2004. In 2005, the MPRB stopped monitoring stormwater in St. Paul, and four new sites in Minneapolis were selected for monitoring. In 2006, new sites were chosen in Minneapolis to comply with the NPDES permit and to assist with modeling and load allocation efforts.

In 2015, the same four sites, representing the major land uses in Minneapolis -- residential, commercial/industrial, mixed use, and parkland -- were monitored for stormwater runoff quantity and quality. Representative sampling is mathematically extrapolated to calculate potential nutrient and contaminant loading on a citywide scale under the “no BMP” scenario. While the results do not represent actual impacts of stormwater discharge to receiving waters because they do not reflect the effects of structural controls and management practices, they nevertheless are useful for comparing land uses and to create baseline conditions for water quality modeling exercises.

METHODS

The summary below includes descriptions of equipment installation at each site, parameters monitored, field quality assurance sampling, computer models used, data handling, validation, and reporting.

Site Installation The ISCO equipment installed at each site included a 2150 datalogger with low profile area/velocity pressure transducer probe, 2105 interface module, 2105ci or 2103ci cell phone modem, and a 3700 sampler. The 3700 sampler collected stormwater through 3/8” ID vinyl intake tubing complete with strainer. The dataloggers flow-paced the samplers to collect flow-weighted stormwater samples over the entire storm hydrograph. Each site automatically uploaded data, via cell phone modem, to the network server database Monday through Friday. Each site could also be communicated with remotely by Flowlink Pro software in order to adjust pacing, enable or disable samplers, and see if a site had triggered.

2015 Water Resources Report – Minneapolis Park & Recreation Board Page 22-1

Equipment installation began when freezing spring temperatures were no longer a concern in order to prevent area velocity transducer damage. See Figure 22-1 for a map of site locations. Site 6 (22nd/Aldrich) was installed on 4/27/15. Site 7 (14th/Park), was installed on 4/21/15. Site 8a (Pershing Park) was installed on 4/23/15. Site 9 (61st/Lyndale) was installed on 4/22/15. See Table 22-1 for site characteristics.

Figure 22-1. Map of the 2015 NPDES sites located in Minneapolis.

Table 22-1. 2015 NPDES stormwater monitoring sites for Minneapolis.

Site ID Site 6 Site 7 Site 8a Site 9 22nd St & Aldrich Pershing Field east of 49th 335 ft. east of 61st St & Location E 14th St & Park Ave S Ave S St & Chowen Ave Harriet Ave S

Multi–Family Commercial/Industrial/ Land Use Recreational/Parkland Commercial/Industrial Residential High Rise Residential Area (acres) 8.9 13.1 2.5 34.9 Pipe Diameter 18 42 12 36 (inches)

Outfall ID# 10 – 430J 10 – 430D 57 – 100A/B 71 – 070

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Sample Collection and Monitored Parameters The MS4 permit target frequency for storm event sample collection is 15 samples per site, per year. If a sample was missed during one month due to lack of precipitation events, then two or more were taken the next month. In 2015, flow-paced storm event samples were collected from May through early November.

The total volume sampled for each site and total recorded volumes in 2015 are given in Table 22-2 along with the seasonal aggregate percentage sampled. Detailed information on sampling events is shown in Table 22-3.

Table 22-2. NPDES site volume totals for the sampling period 5/7/15 – 10/31/15.

Site 6 Site 7 Site 8a Site 9 Total volume recorded (with Flowlink) for 2015 (cf) 200,637 880,892 72,779 1,550,345 Total volume of sampled events (cf) 130,921 350,914 42,833 790,220 % sampled ANNUAL 65% 40% 59% 51% % sampled SPRING (May- June) 30% 48% 7% 41% % sampled SUMMER (July- September) 40% 34% 90% 44% % sampled FALL (October- November) 29% 18% 3% 14%

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Table 22-3. 2015 precipitation event data and samples collected for NDPES sites. A precipitation event is defined as being greater than 0.10 inches and separated by 8 hours. The rain gage is located at 3800 Bryant Ave. S., Minneapolis, MN. 2015 NPDES Events Collected

Time since Start End Precip Duration Intensity last Precip. Sample Site 6 Site 7 Site 8a Site 9 Event Date/Time Date/Time (inches) (hours) (in/hr) (hours) Type 22nd/Aldrich 14th/Park Pershing 61st/Lyndale +1 1/26/2015 14:00 n/a n/a n/a n/a n/a n/a grab X(w/Ecoli) X(w/Ecoli) X(w/Ecoli) +2 2/24/2015 13:30 n/a n/a n/a n/a n/a n/a grab X(w/Ecoli) X(w/Ecoli) X(w/Ecoli) +3 3/9/2015 13:45 n/a n/a n/a n/a n/a n/a grab X(w/Ecoli) 4 5/7/2015 6:00 5/8/2015 2:45 0.10 20.75 0.005 26 composite X 5 5/10/2015 12:30 5/11/2015 1:15 0.70 12.75 0.05 58 composite X X 6 5/14/2015 7:45 5/14/2015 23:00 0.33 15.25 0.02 78 composite X(lmtd) X X 7 5/24/2015 2:45 5/25/2015 9:15 0.72 30.5 0.02 150 composite X(lmtd) X(lmtd) X(lmtd) X(lmtd) 8 5/26/2015 10:15 5/27/2015 12:30 1.19 26.25 0.05 25 composite X(w/Ecoli) X(w/Ecoli) X X(w/Ecoli) 9 5/29/2015 3:15 5/29/2015 4:30 0.29 1.25 0.23 39 composite X(lmtd) X X(lmtd) X 10 5/29/2015 14:30 5/29/2015 21:30 0.28 7 0.04 10 composite X(lmtd) X(lmtd) X(lmtd) X(lmtd) 11 6/3/2015 8:15 6/3/2015 20:15 0.72 12 0.06 107 composite X X X X 12 6/6/2015 23:30 6/7/2015 0:00 0.32 0.5 0.64 75 composite X(lmtd) X(lmtd) X(lmtd) X(lmtd) 13 6/11/2015 4:45 6/11/2015 15:45 0.31 11 0.03 101 composite X X 14 6/17/2015 13:45 6/17/2015 14:15 0.16 0.5 0.32 142 composite X(lmtd) 15 6/20/2015 5:45 6/20/2015 8:15 0.39 2.5 0.16 64 composite X(lmtd) X(lmtd) 16 6/22/2015 7:00 6/22/2015 16:15 1.52 9.25 0.16 47 composite X X 17 7/12/2015 23:30 7/13/2015 10:00 1.65 10.5 0.16 155 composite X X 18 7/15/2015 7:00 7/15/2015 17:00 0.13 10 0.01 45 composite X 19 7/17/2015* 0:00 7/18/2015 3:00 0.87 4 0.22 28 composite X(lmtd) X(lmtd) X(lmtd) X(lmtd) 20 7/24/2015 3:15 7/24/2015 6:45 0.47 3.5 0.13 202 composite X(lmtd) 21 7/28/2015 6:15 7/28/2015 12:15 1.49 6 0.25 95 composite X(Ecoli only) X X(w/Ecoli) 22 8/16/2015 17:30 8/17/2015 4:00 0.62 10.5 0.06 229 composite X X X X 23 8/18/2015 10:15 8/19/2015 12:30 0.87 26.25 0.03 15 grab X(Ecoli only) 24 8/22/2015 18:00 8/22/2015 21:00 0.29 3 0.10 77 grab X(lmtd) X(lmtd) X(lmtd) X(lmtd) 25 9/16/2015 19:45 9/17/2015 17:30 0.88 21.75 0.04 153 composite X(Ecoli only) X(Ecoli only) X(Ecoli only) 26 9/18/2015 16:30 9/18/2015 22:15 0.27 5.75 0.05 23 comp/grab X(lmtd) 27 10/8/2015 3:45 10/8/2015 8:15 0.29 4.5 0.06 320 composite X X X X 28 10/23/2015 5:00 10/24/2015 2:30 1.63 21.5 0.08 357 composite X(lmtd) X(lmtd) X(lmtd) 29 10/27/2015 18:30 10/31/2015 10:30 1.19 88 0.01 88 composite X(lmtd) X X Totals 17.68 21 20 18 19 + snowmelt event n/a = not applicable X = event sampled with full parameters X(lmtd) = event sampled with limited parameters generally due to holding times e.g.BOD, Ortho P, and TDP X(w/Ecoli) = event sampled with E. coli X(Ecoli only) = only E. coli sampled *NWS data collected at MSP airport

2015 Water Resources Report – Minneapolis Park & Recreation Board Page 22-4

Table 22-4 shows the parameters tested as part of the MS4 permit for each sample collected. Table 22-5 gives the approved methods used for analysis, reporting limit, and holding time for each parameter as reported by the contract laboratory Instrumental Research, Inc. (IRI). Legend Technical Services Laboratory analyzed all metals samples.

Limited parameter sample designation is when the sample is collected after some of the parameters (e.g. BOD, TDP) holding times have expired and those parameters are not analyzed. In 2015, limited parameters were collected nineteen times. These samples were recovered after more than 24 hours and parameters with short holding times were not analyzed (e.g. cBOD, TDP) or there was limited composite volume.

As required by the MS4 permit, Escherichia Coli (E. coli) grab and pH samples were collected by quarterly sampling. E.coli was collected annually at all sites except at Site 8a (Pershing). Site 8a was inaccessible for grab sampling after snowmelt and equipment installation. When flow and time were sufficient, E. coli grab samples were collected. A total of sixteen E. coli grabs were collected in 2015. Site 6 (22nd/Aldrich), Site 7 (14th and Park), and Site 9 (61st and Lyndale) were each collected five times. Site 8a (Pershing) was collected once. If the pH was measured in the field it was using an Oakton Waterproof pHTestr 2™ or it was performed at the IRI laboratory. If the Oakton field meter was used, the pH meter was calibrated with 2-point calibration prior to each sampling trip.

With the exception of Site 8 (Pershing) all required E. coli grab and pH sampling was successfully accomplished in 2015.

Table 22-4. The list of monitored chemical parameters for the NPDES permit. BOD is biochemical oxygen demand.

Parameter Abbreviation Units Sample Type BOD –carbonaceous, 5 Day cBOD mg/L Composite Chloride, Total Cl mg/L Composite Specific Conductivity Sp. Cond µmhos/cm Composite E. coli (Escherichia Coli) E. coli MPN/100mL Grab (4X year) Hardness Hard mg/L Composite Copper, Total Cu µg/L Composite Lead, Total Pb µg/L Composite Zinc, Total Zn µg/L Composite

Nitrite+Nitrate, Total as N NO3NO2 mg/L Composite

Ammonia, Un-ionized as N NH3 mg/L Composite Kjeldahl Nitrogen, Total TKN mg/L Composite pH pH standard unit Grab/Comp (4X year) Phosphorus, Ortho-P Ortho-P mg/L Composite Phosphorus, Total Dissolved TDP mg/L Composite Phosphorus, Total TP mg/L Composite Solids, Total Dissolved TDS mg/L Composite Solids, Total Suspended TSS mg/L Composite Solids, Volatile Suspended VSS mg/L Composite

Sulfate SO4 mg/L Composite

2015 Water Resources Report – Minneapolis Park & Recreation Board Page 22-5

Table 22-5. Analysis method, reporting limit, and holding times for parameters used by Instrumental Research, Inc.

Parameter Method Reporting Limit Holding Times cBOD, carbonaceous, 5 Day (20°C) SM 5210 B 1.0 mg/L 24 hours Chloride, Total SM 4500-Cl- B 2.0 mg/L 28 days Specific Conductivity SM 2510 B 10 µmhos/cm 28 days E. coli (Escherichia Coli) SM 9223B 1 MPN per 100mL < 24hrs Hardness SM 2340 C 2.0 mg/L 6 months Copper, Total EPA 200.9 1.4 µg/L 6 months Lead, Total SM 3500-Pb B 3 µg/L 6 months Zinc, Total SM 3500-Zn B 2 µg/L 6 months Nitrite+Nitrate, Total as N SM 4500-NO3 E 0.030 mg/L 28 days Ammonia, Un-ionized as N SM 4500-NH3 F 0.500 mg/L 7 days Kjeldahl Nitrogen, Total SM 4500-Norg B 0.500 mg/L 7 days pH SM 4500 H+ B 0.01 units 15 minutes Phosphorus, Ortho-P SM 4500-P A, B, G 0.010 mg/L 48 hours Phosphorus, Total Dissolved SM 4500-P A, B, G 0.010 mg/L 48 hours Phosphorus, Total SM 4500-P A, B, E 0.010 mg/L 48 hours Solids, Total Dissolved SM 2540 C 10.0 mg/L 7 days Solids, Total Suspended SM 2540 D 1.0 mg/L 7 days Solids, Volatile Suspended SM 2540 E 2.0 mg/L 7 days Sulfate* ASTM D516-90 15 mg/L 28 days Sulfate* samples were spiked (with 10 mg/L) and the spike was later subtracted to lower the 2015 detection limit to 5 mg/L.

FIELD QUALITY ASSURANCE SAMPLES

Ten percent of samples were laboratory quality assurance samples (e.g. duplicates, spikes). Field blanks consisted of deionized water which accompanied samples from the field sites to the analytical laboratory. A field blank was generated for each sampling trip and was analyzed for all NPDES parameters. All field blank parameters were below the minimum detection limits in 2015. As part of the overall QA/QC program, blind monthly performance samples of known concentration were made for all monitored parameters and delivered to IRI.

If the Oakton field pH meter was used, the meter was calibrated with a 2-point calibration prior to each sampling trip.

An equipment blank (~ 2 L sample) was collected at Site 8a (Pershing) 11/05/15. This site has a standard NPDES stormwater monitoring set up. To collect the equipment blank, a large bottle of deionized water was placed at the strainer end of the sampler tubing. The intake line was filled and flushed with deionized water, simulating the presample flush. After the flush was pumped to waste, a sample of deionized water was collected. The sample taken was of sufficient volume to allow analysis of all parameters. All analytes came back from the laboratory below the minimum detection limits.

Manual transcription of data was minimized to reduce error introduction. A minimum of 10% of the final data were checked by hand against the raw data sent by the laboratory to ensure there were no errors entering, manipulating, or transferring the data. See Section 31, Quality Assurance Assessment Report for details.

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Field measurements were recorded on a Field Measurement Form in the 2015 Field Log Book. Electronic data from the laboratory were forwarded to the MPRB in preformatted spreadsheets via email. Electronic data from the laboratory were checked and passed laboratory quality assurance procedures. Protocols for data validity followed those defined in the Storm Water Monitoring Program Manual (MPRB, 2001). For data reported below the reporting limit, the reporting limit value was divided in half for use in statistical calculations.

A Chain of Custody form accompanied each set of sample bottles delivered to the lab. Each sampler tray or container was iced and labeled indicating the date and time of collection, the site location, and the field personnel initials. The recorded collection date and time assigned to the sample was the time when the last sample of the composite was collected. The time that each composite sample was collected was recorded from the ISCO sampler onto field sheets. A complete description of methods can be found in the Storm Water Monitoring Program Manual (MPRB, 2001). All statistics were calculated using Microsoft Excel.

Computer Models used (P-8 and Flux) The computer model P8 (v3.4) was calibrated and verified for each site. P8 was used to estimate daily cfs snowmelt runoff from January through May. Daily temperature and hourly precipitation files used as P8 inputs were obtained from the National Oceanic and Atmospheric Administration (NOAA) National Data Center (NDC). Data from a heated rain gauge (for snowmelt water equivalent) was used and is located at the Minneapolis/St. Paul International Airport.

A description of P8 as described in the software’s introduction: P8 is a model for predicting the generation and transport of stormwater runoff pollutants in small urban catchments. Simulations are driven by hourly rainfall and daily air-temperature time series.

The P8 estimated daily average cfs snowmelt data, with the ISCO Flowlink measured daily average cfs runoff data, the grab and composite water chemistry data were put into Flux32 (v3.10) and used to calculate flow-weighted mean concentrations.

In Flux32, all the chemical parameters were run unstratified, and if possible, stratified by flow and month. A minimum of three data points are required to “cut the data” in any stratification. Flux32 methods 2 and 6 were recorded for each parameter run. The modeled concentration value with the lowest coefficient of variation was chosen and used for load calculations.

A description of Flux32 as described in the help menu (US Army Corps, 2009):

Flux32 is interactive software designed for use in estimating the transport (load) of nutrients or other water quality constituents past a tributary sampling station over a given period of time. The basic approach of Flux32 is to use several calculation techniques to map the flow/concentration relationship developed (modeled) from the sample record onto the entire flow record. This provides an estimate of total mass transport for the whole period of study with associated error statistics. Note that this approach does NOT focus on estimating changes in loads over time (i.e. time series).

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An important option within Flux32 is the ability to stratify the data into groups based upon flow, date, and/or season. This is a key feature of the FLUX approach and one of its greatest strengths. In many (most) cases, stratifying the data increases the accuracy and precision of loading estimates.

RESULTS & DISCUSSION

Seasonal statistics (snowmelt, spring, summer, and fall) of the data for the combination of all sites were calculated and are listed in Table 22-6. Seasonal patterns are evident. Snowmelt had the highest geometric mean concentrations for all of the parameters, except E. coli. The snowmelt E. coli concentrations were the lowest measured. Bacteria are temperature dependent and do not grow well in the cold. Spring stormwater had the lowest geometric mean concentrations for TDP and Pb.

Summer had the lowest geometric mean concentrations of TP, Ortho-P, TKN, NH3, Cl, Hardness, TSS, TDS, cBOD, Sulfate, Cu and Zn. Fall had the highest geometric mean concentrations for E. coli. Fall had lowest geometric mean concentration for the parameters: NO2NO3 and VSS.

2015 Water Resources Report – Minneapolis Park & Recreation Board Page 22-8

Table 22-6. 2015 statistical summary of concentrations by season from all sites (6 –9).

2015 Statistical TP TDP Ortho-P TKN NH3 NO3NO2 Cl Hardness TSS VSS TDS cBOD Sulfate pH E. coli Cu Pb Zn Season Function mg/L mg/L mg/L mg/L mg/L mg/L mg/L mg/L mg/L mg/L mg/L mg/L mg/L std units MPN/100mL ug/L ug/L ug/L MEAN (geometric) 0.477 0.196 0.226 5.36 1.79 0.502 1847 215 124 50 2393 39 42 7.6 610 29 10 115 MEAN (arithmetic) 0.598 0.348 0.348 5.67 2.49 1.56 4767 290 174 71 4502 55 62 7.7 3024 43 18 218 MAX 1.68 1.12 1.15 8.26 5.39 6.06 12513 570 385 165 14457 117 145 11.6 12033 92 41 520 SNOWMELT MIN 0.249 0.054 0.093 2.79 0.587 0.045 37 64 25 14 214 14 12 6.5 29 3 2 10 (January-March) MEDIAN 0.459 0.147 0.158 6.16 1.58 0.781 3525 216 102 52 1726 32 50 6.8 345 29 14 160 STDEV 0.506 0.390 0.389 1.93 2.033 2.29 4727 216 140 59 4958 46 52 2.0 5127 32 15 201 NUMBER 77 777 67 7 777 7 7 7 5777 COV 0.847 1.12 1.12 0.340 0.816 1.47 0.992 0.745 0.805 0.841 1.10 0.823 0.836 0.256 1.70 0.758 0.827 0.921 MEAN (geometric) 0.245 0.065 0.101 1.96 0.446 0.270 30 32 68 29 67 6 5 7.0 7270 4 4 47 MEAN (arithmetic) 0.297 0.075 0.126 2.29 0.531 0.297 42 37 102 37 83 8 6 7.1 7270 9 8 71 MAX 0.754 0.147 0.378 6.56 1.69 0.654 247 110 396 125 299 22 16 8.6 7270 73 35 400 SPRING MIN 0.059 0.032 0.029 0.66 0.237 0.106 9 16 5 3 30 1 3 6.5 7270 3 2 10 (April-May) MEDIAN 0.266 0.052 0.093 2.00 0.381 0.266 27 28 78 34 74 7 5 6.9 7270 3 4 46 STDEV 0.190 0.042 0.095 1.44 0.411 0.132 51 22 101 26 72 6 4 0.5 17 11 86 NUMBER 22 12 12 19 11 20 20 20 20 20 12 11 12 19 1 19 19 19 COV 0.640 0.559 0.758 0.630 0.774 0.444 1.22 0.606 0.986 0.708 0.866 0.703 0.705 0.069 1.82 1.36 1.21 MEAN (geometric) 0.215 0.072 0.079 1.45 0.345 0.265 3 21 55 22 40 5 3 6.6 10478 4 6 45 MEAN (arithmetic) 0.242 0.087 0.090 1.79 0.392 0.301 6 23 75 27 50 5 3 6.7 10502 8 12 74 MAX 0.701 0.270 0.236 5.87 0.773 1.02 40 50 252 82 158 14 6 7.7 11199 77 70 640 SUMMER MIN 0.083 0.017 0.023 0.250 0.250 0.090 1 10 12 4 13 3 3 6.1 9804 3 2 10 (June-August) MEDIAN 0.195 0.073 0.076 1.52 0.250 0.282 1 21 60 23 38 5 3 6.6 10502 3 6 53 STDEV 0.133 0.058 0.048 1.16 0.221 0.173 9 10 58 17 37 3 1 0.4 986 15 16 113 NUMBER 33 16 17 33 16 31 31 32 32 32 20 14 16 16 2 30 30 30 COV 0.550 0.672 0.537 0.649 0.565 0.574 1.44 0.448 0.770 0.636 0.739 0.557 0.420 0.060 0.094 1.94 1.34 1.52 MEAN (geometric) 0.417 0.172 0.207 1.48 0.493 0.254 5 31 56 18 98 16 12 6.4 11140 6 6 74 MEAN (arithmetic) 1.34 0.197 0.236 2.15 0.65 0.419 10 37 87 34 143 22 22 6.4 11734 10 12 94 MAX 12.6 0.324 0.387 5.47 1.44 1.43 38 120 233 91 600 59 110 6.7 17329 31 79 220 FALL MIN 0.074 0.067 0.068 0.250 0.190 0.033 1 14 3 1 45 7 6 6.1 8664 3 2 10 (Sept-Nov) MEDIAN 0.435 0.201 0.251 1.48 0.456 0.286 5 30 70 23 80 11 9 6.4 9208 3 5 75 STDEV 3.39 0.100 0.111 1.67 0.487 0.420 12 28 69 30 186 20 36 0.2 4853 11 22 59 NUMBER 13 8 7 13 8 13 13 12 13 13 8 7 8 7 3 12 12 12 COV 2.53 0.508 0.470 0.776 0.751 1.00 1.25 0.761 0.788 0.859 1.30 0.912 1.66 0.027 0.414 1.03 1.78 0.624 -highest concentration -lowest concentration

STDEV= standard deviation, COV= coefficient of variation, Blue highlighted cells have the highest seasonal geometric mean, Orange have the lowest seasonal geometric mean.

2015 Water Resources Report – Minneapolis Park & Recreation Board Page 22-9

Table 22-7 shows the 2015 sampled storm event raw data concentrations. These data generally show peaks during snowmelt and early spring for many parameters, but at some sites there are additional peaks that occurred in late fall. Stormwater concentrations can be extremely variable because the concentrations can be due to precipitation, the intensity of precipitation, BMP activity and maintenance, etc.

2015 Water Resources Report – Minneapolis Park & Recreation Board Page 22-10

Table 22-7. 2015 NDPES sampled event data by site. Date Sampled Time Site Location Sample TP TDP OPO4 TKN NH3 NO3NO2 Cl Hardness TSS VSS TDS cBOD Sulfate Sp.Cond. pH E. Coli Cu Pb Zn Type mg/L mg/L mg/L mg/L mg/L mg/L mg/L mg/L mg/L mg/L mg/L mg/L mg/L uhmos s td units MPN ug/L ug/L ug/L 1/26/2015 14:45 Site 6, 22nd & Aldrich Grab 0.737 0.561 0.549 6.16 3.10 1.60 983 108 102 52 1726 17 18 3650 6.7 12033 29 28 160 2/24/15 13:30 Site 6, 22nd & Aldrich Grab 0.459 0.087 0.093 8.26 5.01 0.045 8768 424 385 165 6022 117 100 29900 6.5 345 82 41 460 5/11/2015 0:51 Site 6, 22nd & Aldrich Composite 0.312 0.104 0.078 2.70 0.593 0.168 71 16 138 64 47 9 <5.0 64 6.8 22 34 99 5/14/2015 20:08 Site 6, 22nd & Aldrich Composite 0.478 0.140 0.186 2.86 0.417 50 24 63 39 64 5 88 5/25/2015 3:30 Site 6, 22nd & Aldrich Composite 0.318 2.97 0.106 22 26 39 26 66 6.6 <5.00 7 46 5/26/2015 19:40 Site 6, 22nd & Aldrich Composite 0.240 0.047 0.073 2.17 0.359 0.254 20 22 80 30 35 3 <5.0 43 7.1 <5.00 5 22 5/28/2015 14:30 Site 6, 22nd & Aldrich Grab >2420 5/29/2015 4:01 Site 6, 22nd & Aldrich Composite 0.754 151 5/29/2015 18:57 Site 6, 22nd & Aldrich Composite 0.267 2.50 0.209 9 28 89 40 66 6.8 <5.00 29 77 6/3/2015 19:03 Site 6, 22nd & Aldrich Composite 0.580 0.115 0.038 5.87 0.768 0.108 9 30 252 82 62 14 6 106 6.3 77 13 640 6/7/2015 0:28 Site 6, 22nd & Aldrich Composite 0.226 2.58 0.262 <2.0 18 140 41 61 <5.00 70 110 6/11/2015 8:04 Site 6, 22nd & Aldrich Composite 0.333 0.110 0.147 2.31 0.341 <2.0 22 81 48 37 <5.00 85 6.8 6/20/2015 6:20 Site 6, 22nd & Aldrich Composite 0.334 2.98 0.302 <2.0 28 44 20 79 20 24 75 6/22/2015 8:22 Site 6, 22nd & Aldrich Composite 0.141 0.124 0.067 0.522 <0.500 0.224 <2.0 12 24 12 13 5 <5.00 34 6.6 <5.00 8 33 7/13/2015 0:30 Site 6, 22nd & Aldrich Composite 0.172 0.017 0.023 1.48 <0.500 0.213 <2.0 10 47 24 16 3 <5.0 39 6.4 <5.00 17 40 7/18/2015 2:50 Site 6, 22nd & Aldrich Composite 0.108 0.945 0.309 <2.0 16 40 16 43 <5.00 19 50 7/28/2015 8:50 Site 6, 22nd & Aldrich Grab >24200 8/16/2015 19:54 Site 6, 22nd & Aldrich Composite 0.349 0.108 0.093 2.66 0.773 0.497 <2.0 36 80 30 30 8 <5.0 68 6.5 21 45 110 8/22/2015 20:52 Site 6, 22nd & Aldrich Composite 0.281 2.32 0.275 <2.0 16 108 38 66 20 47 89 9/17/2015 13:50 Site 6, 22nd & Aldrich Composite 8664 10/8/2015 5:16 Site 6, 22nd & Aldrich Composite 0.639 0.202 0.387 3.95 0.633 0.065 5 30 131 91 76 59 8 112 6.1 15 10 60 10/28/2015 0:02 Site 6, 22nd & Aldrich Composite 0.339 2.07 0.033 3 26 70 48 82 <5.00 19 65 1/26/2015 14:30 Site 7, 14th & Park Grab 0.473 0.409 0.250 2.79 0.587 0.499 783 64 81 37 1346 14 15 2870 6.8 2420 28 14 130 2/24/15 13:45 Site 7, 14th & Park Grab 0.249 0.064 0.095 6.98 5.390 0.069 12513 540 343 141 14457 81 145 43000 6.8 <1 92 31 520 5/14/2015 21:07 Site 7, 14th & Park Composite 0.186 0.043 0.108 1.29 <0.500 0.654 45 30 28 19 84 10 9 125 7.5 <5.00 4 68 5/25/2015 2:51 Site 7, 14th & Park Composite 0.109 0.655 0.331 20 20 51 47 65 6.8 <5.00 <3.00 29 5/26/2015 11:30 Site 7, 14th & Park Grab 7270 5/26/2015 18:59 Site 7, 14th & Park Composite 0.609 0.032 0.062 1.11 0.314 0.186 25 20 45 20 30 <1.00 <5.0 57 7.3 <5.00 <3.00 25 5/29/2015 4:20 Site 7, 14th & Park Composite 0.240 0.048 0.124 2.00 0.381 0.435 45 26 105 45 40 12 6 72 6.5 <5.00 <3.00 23 5/30/2015 19:06 Site 7, 14th & Park Composite 0.086 0.909 0.127 10 28 34 14 86 6.7 <5.00 4 45 6/3/2015 19:50 Site 7, 14th & Park Composite 0.286 0.035 0.063 2.75 <0.500 0.364 24 20 150 44 69 6 <5.00 129 6.6 <5.00 7 50 6/7/2015 1:09 Site 7, 14th & Park Composite 0.153 2.07 0.281 2 22 68 22 83 <5.00 14 88 6/11/2015 8:43 Site 7, 14th & Park Composite 0.151 0.049 0.082 0.944 0.580 0.494 2 20 17 11 76 5 89 6.6 6/20/2015 8:33 Site 7, 14th & Park Composite 0.132 1.20 0.439 4 22 46 22 74 <5.00 7 73 6/22/2015 8:15 Site 7, 14th & Park Composite 0.135 0.054 0.074 0.92 <0.500 0.14 <2.0 14 47 20 18 7 <5.00 43 6.3 <5.00 11 55 7/18/2015 2:47 Site 7, 14th & Park Composite 0.083 <0.500 0.351 <2.0 12 12 4 44 <5.00 3 25 8/16/2015 19:44 Site 7, 14th & Park Composite 0.257 0.076 2.31 0.642 36 8/18/2015 15:50 Site 7, 14th & Park Grab 9804 8/22/2015 21:22 Site 7, 14th & Park Composite 0.178 1.52 0.253 3 16 96 30 68 <5.00 9 73 9/17/2015 13:40 Site 7, 14th & Park Grab 17329 10/8/2015 5:03 Site 7, 14th & Park Composite 0.513 0.067 0.271 3.51 1.02 0.933 6 36 119 51 84 39 10 125 6.4 19 7 110 10/24/2015 13:57 Site 7, 14th & Park Composite 0.159 1.48 0.184 4 30 62 23 100 <5.00 4 58 10/28/2015 9:02 Site 7, 14th & Park Composite 0.074 0.103 0.068 <0.500 <0.500 0.366 1 18 3 <2.0 45 11 7 50 6.3 <5.00 <3.00 220 10/28/2015 23:46 Site 7, 14th & Park Composite 0.222 0.103 0.122 0.980 0.190 0.076 5 32 34 16 76 11 8 102 6.4 <5.00 6 82 2015 Water Resources Report – Minneapolis Park & Recreation Board Page 22-11

Table 22-7. 2015 NDPES sampled event data by site. (Continued)

Date Sampled Time Site Location Sample TP TDP OPO4 TKN NH3 NO3NO2 Cl Hardness TSS VSS TDS cBOD Sulfate Sp.Cond. pH E. Coli Cu Pb Zn Type mg/L mg/L mg/L mg/L mg/L mg/L mg/L mg/L mg/L mg/L mg/L mg/L mg/L uhmos s td units MPN ug/L ug/L ug/L 3/9/15 13:45 Site 8, Pershing Grab 1.68 1.12 1.15 4.65 1.05 <0.030 37 110 25 20 214 32 12 330 6.5 291 <5.00 <3.00 <20.0 5/25/2015 2:10 Site 8, Pershing Composite 0.059 0.168 30 20 5 3 22 6.7 <5.00 <3.00 <20.0 5/26/2015 17:26 Site 8, Pershing Composite 0.267 0.055 0.063 2.11 0.480 0.266 20 26 76 36 41 5 <5.0 61 6.8 <5.00 <3.00 <20.0 5/29/2015 4:06 Site 8, Pershing Composite 0.424 150 5/29/2015 18:41 Site 8, Pershing Composite 0.140 1.12 0.243 9 28 30 14 34 6.6 <5.00 <3.00 23 6/3/2015 18:48 Site 8, Pershing Composite 0.214 0.097 0.073 1.61 <0.500 0.282 9 30 42 30 39 5 <5.00 56 6.9 <5.00 <3.00 25 6/7/2015 0:17 Site 8, Pershing Composite 0.127 1.18 0.166 4 12 14 7 29 <5.00 <3.00 <20.0 6/17/2015 14:07 Site 8, Pershing Composite 0.432 3.92 0.160 3 34 119 56 95 29 13 130 7/13/2015 0:58 Site 8, Pershing Composite 0.256 0.040 0.059 1.68 <0.500 0.102 <2.0 30 56 47 14 4 <5.0 66 6.6 <5.00 <3.00 <20.0 7/15/2015 17:08 Site 8, Pershing Composite 0.142 0.074 0.062 1.19 <0.500 0.303 <2.0 18 16 8 32 3 <5.0 47 6.5 <5.00 <3.00 <20.0 7/18/2015 2:34 Site 8, Pershing Composite 0.701 2.92 0.494 <2.0 50 64 26 158 <5.00 5 25 7/24/2015 5:43 Site 8, Pershing Composite 0.265 1.03 44 15 62 <5.00 <3.00 30 7/28/2015 7:54 Site 8, Pershing Composite 0.151 0.104 0.104 <0.500 <0.500 0.090 <2.0 10 23 9 37 3 3 22 6.1 <5.00 <3.00 <20.0 8/16/2015 2:26 Site 8, Pershing Composite 0.363 0.270 0.236 1.63 0.751 1.02 1 16 13 10 33 7 <5.0 <10.0 6.5 <5.00 <3.00 <20.0 8/22/2015 21:08 Site 8, Pershing Composite 0.190 1.26 0.335 <2.0 12 13 6 34 <5.00 <3.00 <20.0 9/24/2015 7:01 Site 8, Pershing Composite 0.176 1.23 0.336 <2.0 18 46 18 42 <5.00 <3.00 32 10/8/2015 5:11 Site 8, Pershing Composite 0.719 0.200 0.328 3.89 1.13 0.904 4 38 117 42 88 6 113 6.5 28 79 140 10/24/2015 1:34 Site 8, Pershing Composite 0.112 0.780 0.128 <2.0 14 13 7 39 <5.00 <3.00 <20.0 1/26/2015 14:05 Site 9, 61st & Lyndale Grab 0.321 0.147 0.158 3.99 0.721 1.06 3525 216 201 65 6022 18 50 12915 9.3 29 41 12 220 2/24/15 14:15 Site 9, 61st & Lyndale Grab 0.263 0.054 0.136 6.88 1.58 6.065 6759 570 83 14 1726 109 93 33400 11.6 <1 25 <3.00 25 5/7/2015 18:35 Site 9, 61st & Lyndale Composite 0.701 0.147 0.029 6.56 1.69 0.242 247 110 396 125 299 22 16 449 7.4 73 35 400 5/11/2015 8:42 Site 9, 61st & Lyndale Composite 0.136 0.086 0.056 1.92 0.527 0.354 52 40 118 35 92 8 7 179 7.5 24 9 120 5/14/2015 22:08 Site 9, 61st & Lyndale Composite 0.294 0.116 0.183 1.66 0.692 0.447 50 60 79 28 96 6 <5.00 172 7.5 <5.00 5 91 5/25/2015 13:22 Site 9, 61st & Lyndale Composite 0.265 5.17 0.265 44 52 29 15 268 7.1 <5.00 <3.00 52 5/26/2015 11:05 Site 9, 61st & Lyndale Grab >24200 5/26/2015 15:24 Site 9, 61st & Lyndale Composite 0.133 0.045 0.378 2.39 0.314 0.357 20 64 341 66 89 4 5 127 8.6 <5.00 4 66 5/29/2015 7:13 Site 9, 61st & Lyndale Composite 0.301 0.036 0.171 1.74 0.237 0.397 40 44 164 42 83 7 7 123 6.9 <5.00 <3.00 42 5/30/2015 4:44 Site 9, 61st & Lyndale Composite 0.221 1.60 0.313 14 52 132 33 124 7.2 23 9 100 6/3/2015 19:20 Site 9, 61st & Lyndale Composite 0.303 0.071 0.110 3.13 <0.500 0.189 14 44 136 39 80 5 6 7.2 <5.00 <3.00 56 6/7/2015 3:47 Site 9, 61st & Lyndale Composite 0.253 1.90 0.311 17 36 162 34 152 <5.00 7 110 7/18/2015 3:53 Site 9, 61st & Lyndale Composite 0.149 0.982 0.303 14 26 88 24 125 <5.00 6 66 7/28/2015 7:44 Site 9, 61st & Lyndale Composite 0.188 0.052 0.117 0.616 <0.500 0.212 15 38 184 40 43 3 5 139 7.7 <5.00 6 98 7/28/2015 8:05 Site 9, 61st & Lyndale Grab 11199 8/16/2015 23:10 Site 9, 61st & Lyndale Composite 0.172 0.072 0.098 0.927 <0.500 0.309 11 24 76 21 33 3 <5.0 97 7.1 <5.00 6 67 8/22/2015 22:04 Site 9, 61st & Lyndale Composite 0.195 1.07 0.193 40 18 101 19 191 <5.00 5 48 9/17/2015 13:20 Site 9, 61st & Lyndale Grab 9208 10/8/2015 5:29 Site 9, 61st & Lyndale Composite 0.808 0.255 0.251 3.20 1.44 1.43 15 48 186 59 108 20 14 195 6.7 15 5 130 10/24/2015 12:29 Site 9, 61st & Lyndale Composite 0.625 5.47 0.238 35 120 233 78 359 31 9 150 10/27/2015 18:34 Site 9, 61st & Lyndale Composite 12.6 0.324 <0.500 <0.500 0.471 38 89 <2.0 600 7 110 10/29/2015 5:11 Site 9, 61st & Lyndale Composite 0.435 0.324 0.226 0.936 0.279 0.286 10 30 28 12 67 7 9 125 6.2 <5.00 3 68 2015 Water Resources Report – Minneapolis Park & Recreation Board Page 22-12

Median Comparison Table 22-8 shows a comparison of MPRB and Nationwide Urban Runoff Program (NURP) median residential, mixed use, and composite land use stormwater values. The MPRB data are split into 2015 and 2001-2014 data for comparison.

In 2015, all three MPRB land use categories saw a significant decrease or similar value in the median concentrations of all parameters when compared to the NURP data, with the exception of TKN. It is unknown why all MPRB TKN data are higher than the NURP TKN data. A possible explanation is there is more decaying vegetative material in the Minneapolis watersheds than in the NURP watersheds that were studied from 1979 to 1983.

When the NURP study data were collected lead (Pb) was widely used in gasoline (from the 1920’s to 1990’s) and banned after 1996. The lead reduction in the environment is clearly seen in the MPRB data sets.

It is important to note that the MPRB sites monitored in 2001-2004 are located in different watersheds and have similar but not identical land uses to those monitored in 2005-2015.

Table 22-8. Typical Median stormwater sampled concentrations. Land Use Residential Mixed Composite of all categories 1 2 3 4 5 6 Location MPRB MPRB NURP MPRB MPRB NURP MPRB MPRB NURP Year(s ) 2015 2001–2014 2015 2001–2014 2015 2001–2014 TP (mg/L) 0.333 0.412 0.383 0.178 0.234 0.263 0.257 0.345 0.330 TKN (mg/L) 2.62 2.43 1.9 1.29 1.57 1.29 1.91 2.05 1.5 NO3NO2 (mg/L) 0.633 0.352 0.736 0.348 0.423 0.558 0.431 0.423 0.68 cBOD (mg/L) 9111011887109 TSS (mg/L) 80 84 101 49 60 67 76 83 100 Cu (µg/L) 918333 182731830 Pb (µg/L) 22 31 144 6 12 114 6 14 140 Zn (µg/L) 76 78 135 68 82 154 63 81 160

1 Site 6 data. 2 Sites 1 and 2 data, (Site 6, 2005-2014). 3 Site 7 data. 4 Sites 5 and 5a data, (Site 7, 2005-2014). 5 Sites 6 – 9 data. 6 Sites 1 – 5a data, (Site 6 – 9, 2005-2014). NURP = median event mean concentrations as reported by the Nationwide Urban Runoff Program (USEPA, 1996). MPRB = median values calculated by the MPRB for the identified year(s).

2015 Water Resources Report – Minneapolis Park & Recreation Board Page 22-13

Geometric Mean Comparison Table 22-9 lists the statistical calculations for all measured parameters for each site. Most of the geometric mean maximums occurred at Site 9 (61st and Lyndale) the industrial site. The lowest geometric mean values generally occur at Site 8 (Pershing) and Site 7 (14th & Park). This is as expected since Site 8 (Pershing) is parkland and Site 7 (14th & Park) is a mixed use watershed with little vegetation.

Table 22-9. 2015 event concentration statistics. Site Statistical TP TDP Ortho-P TKN NH3 NO3NO2 Cl Hardness TSS VSS TDS cBOD Sulfate pH E. coli Cu Pb Zn ID Function mg/L mg/L mg/L mg/L mg/L mg/L mg/L mg/L mg/L mg/L mg/L mg/L mg/L std units MPN/100mL ug/L ug/L ug/L 6, 22nd Aldrich MEAN (geometric) 0.328 0.106 0.105 2.57 0.203 0.753 8 27 84 39 78 12 5 6.6 3301 9 20 85 6, 22nd Aldrich MEAN (arithmetic) 0.372 0.147 0.158 3.07 0.301 1.30 553 50 106 48 681 26 14 6.6 7014 19 26 134 6, 22nd Aldrich MAX 0.754 0.561 0.549 8.26 1.60 5.01 8768 424 385 165 6022 117 100 7.1 12033 82 70 640 6, 22nd Aldrich MIN 0.108 0.017 0.023 0.52 0.033 0.250 1 10 24 12 13 3 3 6.1 345 3 5 22 6, 22nd Aldrich MEDIAN 0.333 0.110 0.093 2.62 0.239 0.633 4 25 80 39 45 9 3 6.6 8664 9 22 76 6, 22nd Aldrich STDEV 0.189 0.145 0.164 1.92 0.347 1.644 2063 96 88 36 1750 38 29 0.3 6016 25 18 169 6, 22nd Aldrich NUMBER 19 11 11 18 18 9 18 18 18 18 12 9 11 12 3 16 16 16 6, 22nd Aldrich COV 0.509 0.990 1.04 0.624 1.15 1.26 3.73 1.93 0.824 0.748 2.57 1.47 2.08 0.040 0.858 1.33 0.689 1.27 7, 14th Park MEAN (geometric) 0.189 0.067 0.102 1.33 0.278 0.467 12 28 48 21 107 10 8 6.7 7394 4 5 68 7, 14th Park MEAN (arithmetic) 0.226 0.092 0.116 1.78 0.343 0.842 750 53 74 32 1364 19 19 6.7 9206 10 7 98 7, 14th Park MAX 0.609 0.409 0.271 6.98 0.933 5.39 12513 540 343 141 14457 81 145 7.5 17329 92 31 520 7, 14th Park MIN 0.074 0.032 0.062 0.250 0.069 0.190 1 12 3 1 18 1 3 6.3 2420 3 2 23 7, 14th Park MEDIAN 0.178 0.054 0.089 1.29 0.341 0.348 6 22 49 22 72 11 7 6.6 8537 3 6 68 7, 14th Park STDEV 0.151 0.108 0.071 1.53 0.218 1.45 2941 119 77 31 4140 24 42 0.4 6222 22 7 119 7, 14th Park NUMBER 19 11 12 19 18 12 18 19 18 18 12 10 11 13 4 17 17 17 7, 14th Park COV 0.67 1.18 0.609 0.860 0.634 1.73 3.92 2.24 1.04 0.984 3.04 1.26 2.18 0.055 0.676 2.17 0.980 1.21 8, Pershing MEAN (geometric) 0.253 0.133 0.141 1.53 0.258 0.450 3 24 30 15 52 5 3 6.6 291 3 2 18 8, Pershing MEAN (arithmetic) 0.357 0.244 0.260 1.90 0.333 0.551 8 29 42 21 73 8 4 6.6 291 6 7 30 8, Pershing MAX 1.68 1.12 1.15 4.65 1.02 1.13 37 110 119 56 214 32 12 6.9 291 29 79 140 8, Pershing MIN 0.059 0.040 0.059 0.250 0.090 0.250 1 10 5 3 14 3 3 6.1 291 3 2 10 8, Pershing MEDIAN 0.235 0.101 0.089 1.44 0.266 0.365 2 23 30 15 39 5 3 6.5 291 3 2 10 8, Pershing STDEV 0.380 0.360 0.374 1.27 0.278 0.376 11 24 35 16 68 11 3 0.2 9 19 40 8, Pershing NUMBER 18 8 8 16 15 8 16 16 17 17 9 7 8 10 1 17 17 17 8, Pershing COV 1.07 1.47 1.44 0.666 0.834 0.683 1.44 0.830 0.831 0.770 0.939 1.27 0.834 0.030 1.55 2.70 1.36 9, 61st Lyndale MEAN (geometric) 0.338 0.102 0.133 1.94 0.402 0.485 46 56 121 28 166 9 11 7.6 1441 7 5 85 9, 61st Lyndale MEAN (arithmetic) 0.966 0.133 0.159 2.65 0.708 0.652 577 88 149 39 676 17 25 7.7 6812 14 7 106 9, 61st Lyndale MAX 12.6 0.324 0.378 6.88 6.06 1.69 6759 570 396 125 6022 109 110 11.6 11199 73 35 400 9, 61st Lyndale MIN 0.133 0.036 0.029 0.250 0.189 0.237 10 18 28 1 33 3 3 6.2 29 3 2 25 9, 61st Lyndale MEDIAN 0.265 0.086 0.147 1.90 0.311 0.314 35 46 132 34 94 7 7 7.3 9208 3 5 80 9, 61st Lyndale STDEV 2.82 0.103 0.094 2.04 1.33 0.552 1697 129 96 29 1602 28 36 1.4 5958 19 8 87 9, 61st LyndaleNUMBER 1913121919131918191914131314 3 181818 9, 61st Lyndale COV 2.92 0.777 0.591 0.770 1.89 0.846 2.94 1.46 0.644 0.737 2.37 1.70 1.44 0.177 0.875 1.33 1.08 0.818 All MEAN (geometric) 0.270 0.097 0.117 1.79 0.279 0.520 12 32 63 25 98 9 7 6.9 2831 5 6 55 All MEAN (arithmetic) 0.482 0.147 0.166 2.36 0.429 0.827 486 56 94 35 737 18 17 6.9 7145 12 12 92 All MAX 12.6 1.12 1.15 8.26 6.06 5.39 12513 570 396 165 14457 117 145 11.6 17329 92 79 640 All MIN 0.059 0.017 0.023 0.250 0.033 0.190 1 10 3 1 13 1 3 6.1 29 3 2 10 All MEDIAN 0.257 0.097 0.104 1.91 0.284 0.431 10 28 76 29 69 7 6 6.7 8664 3 6 63 All STDEV 1.44 0.188 0.189 1.78 0.742 1.13 1987 102 86 30 2397 27 32 0.9 5691 20 16 116 AllNUMBER 7543437270427171727247394349 11686868 All COV 2.99 1.28 1.14 0.753 1.73 1.37 4.09 1.84 0.915 0.858 3.25 1.52 1.92 0.130 0.797 1.63 1.36 1.27 -Highest value -Lowest value All = all 4 sites, STDEV = standard deviation, COV = coefficient of variation.

Site 6 (22nd & Aldrich) is an older residential watershed. It had the highest geometric means for TKN, NO2NO3, VSS, cBOD, Cu, and Pb. The cause of the higher TKN, and NO2NO3 values may be pet waste or the dense leaf canopy in the watershed adding to the organic nitrogen load. The higher VSS is likely due to the dense leaf canopy adding a higher VSS to the solids load. The higher Cu and Pb are likely the result of vehicular wear inputs (e.g. brake dust, tire weights). The geometric mean concentration of Pb has been persistently high at this site, and is possibly a remnant of lead based paints shedding from the older houses and soils. The low NH3 is due to the oxidation of ammonia and ammonium to NO2NO3.

Site 7 (14th & Park) is a dense mixed use watershed. It had the highest geometric mean concentrations for E coli. This is likely due to pet and wildlife waste in the watershed. Site 7 also had the lowest geometric mean for all phosphorus and the TKN value. This is likely the result of the hard surface landscape, with minimal

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vegetation, in this mixed use watershed.

Site 8 (Pershing) is a park. It had the highest geometric mean TDP and Ortho-P values likely due to decaying organic material in the parkland watershed or turf maintenance. Site 8 also had the lowest geometric mean NO2NO3, Cl, Hardness, TSS, VSS, cBOD, Sulfate, and all metals. This is also likely due to the park’s vegetated watershed. The low E. coli was not used for analysis since it was a single sample collected during snowmelt.

Site 9 (61st and Lyndale) is a Commercial/Industrial watershed. It had the highest geometric mean for TP, NH3, Cl, Hardness, TSS, TDS, Sulfate, and Zn. Site 9 had the lowest geometric mean values for E. coli, where multiple samples were collected. This watershed is a light industrial site (cement factory, natural gas facility, City maintenance facility, etc.) and it is expected that many of the parameters would be higher than other watersheds due to extensive industrial activities.

Mean Comparison Mean data were comparable to typical urban stormwater data from the Nationwide Urban Runoff Program (NURP), Center for Watershed Protection (CWP), and Bannerman et al. (1993) are inTable 22-10.

Data from MPRB Sites 1–5a (2001–2004) and 6–9 (2005–2014) were partially similar to Sites 6–9 in 2015. NO3NO2, Cl, and TDS were higher in 2015. NH3, TSS and the metals Cu, Pb, and Zn were lower in 2015. The 2015 mean increase in Cl and TDS are likely related to a harsher winter climate and more salt use. The mean decrease in NH3, TSS and all the metals Cu, Pb, and Zn are welcome, but the root cause is unknown.

Table 22-10. Typical Mean urban stormwater concentrations. " -- " = not reported.

6 7 8 1 2 Bannerman 4 St. MWMO MPRB MPRB Parameter NURP CWP 3 Mpls PW 5 et al. Paul 2015 2001–2014 2015 TP (mg/L) 0.5 0.3 0.66 0.417 0.484 0.337 0.460 0.482 TDP (mg/L) -- -- 0.27 0.251 -- 0.087 0.146 0.147 TKN (mg/L) 2.3 ------2.46 1.85 2.78 2.36 NO3NO2 (mg/L) 0.86 ------0.362 0.492 0.568 0.827 NH3 (mg/L) ------0.234 -- 0.168 1.02 0.423 Cl (mg/L) -- 230 (winter) ------121 280 548 BOD (mg/L) 12 -- -- 14.9 25 14 16 18 TDS (mg/L) ------73.3 78 290 552 737 TSS (mg/L) 239 80 262 77.6 129 115 124 94 Cu (µg/L) 50 10 16 26.7 30 20.0 24.7 12.3 Pb (µg/L) 240 18 32 75.5 233 14.0 24.3 11.6 Zn (µg/L) 350 140 204 148 194 121 119 92 1 USEPA (1996) 2 Center for Watershed Protection (2000) 3 Monroe study area of Bannerman et al. (1993) 4 City of Minneapolis Public Works Department (1992) – average from a combination of land uses 5 City of St. Paul 1994 stormwater data – average from a combination of land uses 6 Mississippi Watershed Management Organization 2015 data, average of snowmelt and storms from all sites 7 MPRB arithmetic mean data calculated from NPDES Sites 1 – 5a (2001 – 2004), 6 – 9 (2005 – 2014) 8 MPRB arithmetic mean data calculated from NPDES Sites 6 – 9 (2015)

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Flow-Weighted Mean Comparison The flow-weighted mean concentrations presented in Table 22-11 were calculated using FLUX32. Sample chemistry concentrations and associated daily average flows were used as input for these calculations. The data were run unstratified and often stratified by flow or season to achieve the most accurate and precise results. The method (2 or 6) and event mean concentration with the lowest coefficient of variation was generally chosen as the final concentration value. The “rule of sensibility” was used if the value with the lowest coefficient of variation was an extreme outlier, then the next value was chosen.

Table 22-11. Flow–weighted mean concentrations and related statistics for NPDES parameters in 2015.

TP TDP Ortho-P TKN NO3NO2 NH3 Cl* Hardness TSS VSS TDS* cBOD Sulfate Cu Pb Zn Site (mg/L) (mg/L) (mg/L) (mg/L) (mg/L) (mg/L) (mg/L) (mg/L) (mg/L) (mg/L) (mg/L) (mg/L) (mg/L) (µg/L) (µg/L) (µg/L)

6, 22nd Aldrich 0.267 0.089 0.085 2.10 0.217 0.531 8 20 78 34 38 12 3.0 0.011 0.018 0.089

7, 14th Park 0.241 0.051 0.085 1.35 0.285 0.344 877 23 56 24 49 9 5.0 0.003 0.006 0.052

8a, Pershing 0.225 0.109 0.092 1.39 0.213 0.272 3 24 54 27 39 4 3.0 0.003 0.004 0.021

9, 61st Lyndale 0.614 0.107 0.174 1.86 0.334 0.438 28 51 160 39 108 7 12.0 0.016 0.005 0.086

MEAN 0.337 0.089 0.109 1.68 0.262 0.396 229 30 87 31 59 8 5.8 0.008 0.008 0.062

MEDIAN 0.254 0.098 0.089 1.63 0.251 0.391 18 24 67 31 44 8 4.0 0.007 0.006 0.069

STANDEV 0.186 0.027 0.043 0.366 0.058 0.113 432 14 50 7 33 3 4.3 0.006 0.007 0.032 -Highest value -Lowest value * Flow–weighted mean concentrations for Cl and TDS were difficult to estimate using FLUX32 due to large outliers from the two snowmelt samples; these estimates should be used with caution. STANDEV= standard deviation.

Site 6 (22nd & Aldrich) is a multi-family residential watershed. Site 6 had the highest modeled concentrations of TKN, NH3, Pb, and Zn. It is believed this may be due to its location between two heavily traveled thoroughfares (Hennepin and Lyndale) where a mature dense leaf canopy may collect airborne material and deposit it following precipitation. Site 6 had the lowest modeled concentrations of Ortho-P, Hardness, and TDS. Site 7 (14th & Park) is a densely developed mixed-use watershed. Site 7 had the highest Cl modeled parameter. Site 7 had the lowest modeled TDP, TKN, and VSS. These are all likely due to the dense, highly developed, and low vegetation nature of the watershed. Site 8a (Pershing) is a parkland watershed. Site 8a had none of the highest modeled event mean concentrations. Site 8a had the lowest modeled TP, NO2NO3, NH3, Cl, TSS, cBOD, Sulfate, Cu, Pb, and Zn. This is likely due to the more natural vegetative state of the watershed and an absence of road runoff. Site 9 (61st and Lyndale) is a commercial/industrial watershed. Site 9 had the highest modeled concentration of TP, Ortho-P, NO3NO2, Hardness, TSS, VSS, TDS, Sulfate, and Cu. Site 9 had none of the lowest modeled event mean concentrations. Industrial activities in this watershed likely explain the higher pollutant loads. Site 9 is located adjacent to a large cement aggregate mixing facility which may explain the higher TSS values. This site sometimes had a very small baseflow. In 2008, the baseflow was significantly diminished when the cement aggregate mixing facility improved its on-site runoff and ponding. Table 22-12 includes flow-weighted mean pollutant concentrations of data collected in the 1980s and

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reported by the U.S. Geological Survey (USGS) for various sites within the Twin Cities (as cited in MPCA, 2000). The Yates watershed was a stabilized residential area, the Iverson site was a residential watershed under development, and the Sandberg watershed was predominantly a light industrial land-use area, as reported by the USGS. Site 6 (22nd & Aldrich) is more closely related to the Yates residential watershed land-use characteristics. Site 7 (14th & Park) and Site 9 (61st and Lyndale) are more comparable to the Sandberg light industrial watershed land-use characteristics. Table 22-12. 2015 Flow-weighted mean stormwater pollutant concentrations (mg/L) and ranges as reported by the USGS (as cited in MPCA, 2000). Monitoring Site

Iverson Pollutant Yates area Sandburg Site 6 area Site 7 Site 9 (stabilized area (light (22nd Aldrich) (developing (14th Park) (61st Lyndale) residential) industrial) residential)

TSS 133 78 740 337 56 160 (Mean Range) (2 – 758) (24 – 385) (17- 26,610) (7 – 4,388) (3 – 343) (28 – 396) Pb 0.23 0.018 0.02 0.19 0.006 0.005 (Mean Range) (0.015 –1.8) (0.005 -0.070) (0.008-0.31) (0.003 –1.5) (0.002 – 0.031) (0.002 – 0.035) Zn 0.198 0.089 0.235 0.185 0.052 0.086 (Mean Range) (0.02 – 2.2) (0.022 -0.640) (0.028-0.53) (0.02 –0.81) (0.023 – 0.520) (0.025 – 0.400) TKN 3.6 2.10 1.2 2.5 1.35 1.86 (Mean Range) (0.6 – 28.6) (0.52 – 8.26) (1.0 – 29.2) (0.4 – 16.0) (0.250 – 6.98) (0.250 – 6.88) TP 0.63 0.267 0.62 0.63 0.241 0.614 (Mean Range) (0.10 –3.85) (0.108 – 0.754) (0.2 – 13.1) (0.07 – 4.3) (0.074 – 0.609) (0.133 – 12.6)

When comparing the USGS flow-weighted mean concentrations to the MPRB sites in Table 22-12, Site 6 was lower than Yates for all parameters. The Iverson data are shown only for comparison purposes of a developing residential neighborhood. Compared to Sandberg, Sites 7 and 9 have lower flow-weighted mean concentrations for all parameters and are well within the ranges shown in Table 22-12. Site 7 had significantly lower values than Sandberg for all parameters. Site 9 had roughly half of the Sandberg values with the notable exception of TP. The Site 9 TKN was slightly higher than Sandberg’s TKN but was comparable. The overall mean comparison of Table 22-12 to MPRB water quality values at sites 6, 7, 8a, and 9 shows Minneapolis sites were the same or roughly half of the values for the compared parameters. The Minneapolis mean Pb values are much lower than the Yates and Sandburg studies.

Table 22-13 shows the flow-weighted mean concentrations in 2015 compared to previous years. Flow- weighted mean concentrations for Cl and TDS were difficult to estimate using FLUX32 due to large outliers from the snowmelt samples. These estimates should be used with caution. When samples were below the RL (reporting limit), half of the RL was used for calculations.

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Table 22-13. MPRB Flow–weighted mean concentration compared to previous years. Each year is the average flow–weighted mean concentration of all sites monitored that year.

Flow-weighted mean concentrations Sites 1-5a Site 6-9 Parameter 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015 TP (mg/L) 0.470 0.337 0.474 0.332 0.354 0.548 0.472 0.486 0.583 0.341 0.355 0.368 0.369 0.313 0.337 TDP (mg/L) 0.112 0.095 0.114 0.121 0.123 0.135 0.108 0.139 0.249 0.063 0.126 0.123 0.157 0.121 0.089 Ortho-P (mg/L) nc nc nc nc nc nc nc nc nc nc 0.179 0.097 0.194 0.129 0.109 TKN (mg/L) 2.21 1.60 2.10 1.94 3.48 3.54 4.43 3.22 3.61 1.53 1.74 2.00 2.34 2.40 1.68 NO3NO2 (mg/L) 0.398 0.423 0.496 0.382 0.448 0.638 0.496 0.582 0.755 0.414 0.498 0.397 0.402 0.937 0.262 NH3(mg/L) 0.494 0.722 0.346 0.918 1.74 1.64 0.970 0.966 1.64 0.666 0.922 0.719 0.747 1.00 0.396 Cl (mg/L) 37 11 587 40 18 91 412 139 803 60 213 14 72 205 229 Hardness (mg/L) nc na nc nc na nc nc nc nc na 48.0 37 41 41 30 TSS (mg/L) 116 83 116 70 108 156 180 148 121 107 104 101 95 123 87 VSS (mg/L) nc nc nc nc nc nc nc nc nc nc 30.2 31 29 34 31 TDS (mg/L) 306 85 725 130 252 183 737 507 3323 124 693 97 301 359 59 cBOD (mg/L) 12 8 16 20 9 9 17 25 53 7 11 13 13 10 8 Sulfate (mg/L) nc nc nc nc nc nc nc nc nc nc 15.4 18.4 8.1 6.8 5.8 Cd (µg/L) 0.532 0.518 2.11 2.80 2.50 nc nc nc nc nc nc nc nc nc nc Cu (µg/L) 15 31 23 15 19 29 36 16 40 23 25 16 19 13 8 Pb (µg/L) 23 17 22 14 41 31 34 28 23 24 18 15 22 16 8 Zn (µg/L) 180 76 107 76 86 94 133 132 204 100 103 90 79 68 62 nc = data not collected. na= data not analyzed for. Note: Cadmium (Cd) was discontinued from monitoring in 2006 because Cd concentrations had typically been below detection for the Minneapolis/St. Paul area and it was not useful information. It should also be noted the detection limit for Cd has changed over time. In 2002 it was <0.500 µg/L; in 2003 it was <2.00 µg/L and in 2004 it was <5.00 µg/L. In 2011, ortho-P (or TDP), hardness (for metals toxicity calculations), and sulfate were added.

Chemical concentrations in stormwater are highly variable. Climatological factors such as precipitation amount and intensity, street sweeping type and frequency, BMP maintenance schedule frequency, etc. can cause fluctuations in chemical concentrations. Table 22-13 illustrates the variability of stormwater from year to year. The variability from year to year is due to three likely causes. First, the watersheds monitored have occasionally changed. Second, the timing between street sweeping frequency, BMP maintenance frequency, and sampling probably affect variability within the monitoring year and between years. Third, precipitation frequency, intensity, and duration affect results.

Surcharge Events Surcharge events happen during high precipitation totals or high intensity storm events that exceed the drainage capacity of the pipes. Surcharges occur when water backs up in pipes and creates a hydrostatic pressure head, beyond the diameter of the pipe, which can result in inaccurate daily flow calculations and must be considered when evaluating flow-weighted mean concentrations. If surcharge water inundates the auto-sampler tray the samples are considered contaminated and dumped.

Table 22-14 show the 2015 NPDES surcharge dates. With the exception of Site 8a, most of the surcharging events were storms greater than 1 inch.

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Table 22-14. Surcharge events in 2015 at associated NPDES sites. Site Surcharge Dates Site 6 (22nd and Aldrich) 7/13,7/28 18” pipe Site 7 (Park and 14th) None 42” pipe Site 8a (Pershing) 5/26, 5/29, 6/3, 6/7, 6/17, 6/22, 6/28, 7/6, 7/13, 7/15, 7/18, 12” pipe 7/28, 8/7, 8/18, 8/22, 9/6, 9/9, 9/17, 10/8 Site 9 (61st and Lyndale) 7/13, 8/7 42” pipe

Site 8a (Pershing) is of special concern as it had nineteen surcharges in 2015. At this site, storms as small as 0.33 inches or as large as 3.00 inches caused surcharging. At this site, two pipes and overland flow enter the manhole basin/vault and exit the outlet, a 12-inch PVC pipe. The Site 8 watershed/area of Minneapolis is lower in elevation than the surrounding areas, causing a regular back up of many stormsewers in the system. Minneapolis Public Works is aware of this problem. The surcharges at this site do not appear to have caused any flooding problems. Site 8a samples appear to not be significantly affected by surcharging because the sampler is secured in an above ground enclosure.

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th 23. 37 Street Greenway, Parallel SAFL Baffle

BACKGROUND

The 37th greenway project was a flood control project that had some innovative stormwater BMPs incorporated. The project, in North Minneapolis, consisted of several blocks of 37th Street being closed off and turned into a bike and pedestrian path. The water quality project components included a large underground vault used for floodwater retention, iron enhanced sand filters used to treat both street and alley runoff, and St. Anthony Falls Laboratory (SAFL) baffles used to prevent resuspension in catch basin sumps.

SAFL baffles were developed at the University of Minnesota’s Saint Anthony Falls Laboratory. The baffle is a large flat stainless steel plate with large 4”-6” holes in the plate to dissipate the energy of the oncoming stormwater and prevent cavitation in the sump below, Figure 23-1. Normally, SAFL baffles are placed perpendicular, in the sump, to the incoming stormwater. At the 37th greenway catch basins (CB), the SAFL baffles were placed parallel in the sump to the incoming stormwater. This project was undertaken to see if SAFL baffles prevent sediment resuspension when placed parallel to flow in a CB sump rather than when placed perpendicular to flow in a typical installation.

Figure 23-1. Drawing of a SAFL baffle in a sump. Baffle in the diagram is perpendicular to flow, unlike the baffles in the study site.

METHODS

Site Installation and Tools Four catch basins (CB) were chosen for study. Two had SAFL baffles in them (test) and two did not (control). They were located at 37th and Morgan Avenue North (control) and 37th and Newton Avenue North (test) in North Minneapolis. The catch basins were located on each side of the street, directly across from each other.

The 37th & Morgan West CB drainage area was 1.2 acres and the East CB drainage area was 0.8 acres. The 37th & Newton West and East CB drainage areas were each 1 acre. For both sites, the land use was residential with approximately 50% impervious cover and a dense tree canopy. The catch basin sumps 2015 Water Resources Report – Minneapolis Park & Recreation Board Page 23-1

were vacuumed clean by the City Public Works November 3rd, 2014 prior to the start of the study. Orange tape down marks were painted on each side of all the catch basins on November 17th, 2014, Figure 23-2. The watersheds of the test and control sites were comparable because they are similar in size and land use, and they were one block apart so they experience similar environmental conditions.

Figure 23-2. Stormwater flowing into a control catch basin at 37th & Morgan.

A tape down was made with a fiberglass measuring tape and a lightly weighted Plexiglas foot (or plate) attached to the end of it, Figure 23-3. The Plexiglas foot was designed so it would lightly rest on top of the sump precipitate and not compress or plunge into it. A “zero’ tape down reading was taken and recorded from both sides of each clean catch basin on December 7th, 2014. Tapedown readings were taken on each side and averaged into one reading, Figure 23-4. If sediment was uneven in the sump, the average reading should account for uneven loading. As sediment accumulated, the tape down length would become shorter.

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Figure 23-3. Showing tapedown foot construction.

Figure 23-4. Measuring a tapedown from a fixed point to the catch basin.

Data Collection During ice free conditions, tapedown measurements were made every two weeks on both sides from April 1, 2015 to October 28th, 2015. The catch basin grates were removed and the top edge of the catch basin casting, at the painted marks, were used as the fixed measuring points for the tapedowns. The tapedown measurement was when the tape was lowered from the measuring point straight down until the foot rested on the material in the sump. These measurements were recorded on field sheets and later transferred into Excel for analysis and graphing.

RESULTS & DISCUSSION

Initially, it was unknown if placing SAFL baffles parallel to the flow in a CB sump would prevent resuspension of previously captured sediment. Table 23-1 and Figure 23-2 show the data collected in 2015.

In Table 23-1, the catch basins at Newton Avenue are the test catch basins with the SAFL baffles, and Morgan Avenue are the control without SAFL baffles. The two readings taken at each catch basin are averaged in the colored columns. The green columns are the Morgan average and the red columns are the Newton average. The final column shows the average difference in sediment accumulation between the test and control catch basins.

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Table 23-1. Tapedown depths and average tapedown depths (in feet) to a fixed point at each catch basin. *Newton sites were the test catch basins with SAFL baffles. NA=data not available.

Mean Difference Morgan Morgan Morgan Morgaan Morgan Morgan Newton Newton Newton* Newton Newton Newton* Between Date Intls NW SW W Me an NE SE E Mean NW SW W Mean NE SE E Mean Test/Control (feet) 12/1/2014 MP, RB6.186.18 6.18 6.166.21 6.19 6.08 6.13 6.11 6.13 6.18 6.16 0.05 4/1/2015 MP, RB5.965.90 5.93 5.895.88 5.89 5.69 5.65 5.67 5.88 5.91 5.90 0.13 4/14/2015 MP, RB5.615.65 5.63 5.455.01 5.23 5.22 5.35 5.29 5.56 5.64 5.60 -0.01 4/30/2015 MP 5.61 5.65 5.63 5.495.61 5.55 NA NA NA NA NA NA NA 5/11/2015 MP, QS5.555.57 5.56 5.555.40 5.48 5.15 5.19 5.17 5.49 5.51 5.50 0.18 5/27/2015 MP AT5.395.50 5.45 5.265.39 5.33 4.84 4.87 4.86 5.39 5.20 5.30 0.31 6/12/2015 MP AT5.075.25 5.16 5.095.54 5.32 4.57 4.35 4.46 5.23 5.01 5.12 0.45 6/24/2015 MP QS4.825.04 4.93 4.385.09 4.74 4.43 5.10 4.77 5.01 4.65 4.83 0.04 7/8/2015 MP QS5.125.19 5.16 4.545.11 4.83 4.64 4.59 4.62 4.88 4.85 4.87 0.25 7/23/2015 MP RB5.185.13 5.16 4.945.28 5.11 4.67 4.89 4.78 4.91 5.04 4.98 0.26 8/4/2015 MP AT5.195.15 5.17 5.095.21 5.15 4.76 4.79 4.78 4.83 5.04 4.94 0.31 8/19/2015 MP AT5.165.18 5.17 5.015.10 5.06 4.61 4.62 4.62 4.60 4.59 4.60 0.51 9/2/2015 RB AT 5.10 5.06 5.08 5.005.11 5.06 4.58 4.70 4.64 4.48 4.59 4.54 0.48 9/16/2015 MP AT4.925.09 5.01 4.965.10 5.03 4.43 4.30 4.37 4.31 4.43 4.37 0.65 9/30/2015 MP AT5.155.10 5.13 4.955.10 5.03 4.36 4.51 4.44 4.34 4.70 4.52 0.60 10/15/2015 MP AT5.185.06 5.12 4.935.06 5.00 4.31 4.24 4.28 4.60 4.49 4.55 0.65 10/28/2015 MP AT4.944.87 4.91 4.624.76 4.69 3.71 3.67 3.69 4.22 4.04 4.13 0.89

In Figure 23-5, initially there did not appear to be a difference between the test (Newton) and control (Morgan) catch basins. Then mid-summer (~August 1) the catch basins at Newton, with the SAFL baffles, began to show a difference and were accumulating more sediment, presumably by preventing resuspension. At the conclusion of this study the average SAFL baffle catch basin accumulated 10.6 inches (0.89 feet) more sediment than catch basins without SAFL baffles. Although there was some mid-summer resuspension at both sites overall the SAFL baffles appear to prevent resuspension in catch basins even when placed parallel to flow above the sumps.

Anecdotally, the Newton sites were also more odiferous than the Morgan sites. Odor was likely caused by more accumulated organic material in the Newton sump being digested.

Figure 23-5. Average tapedown depths to a fixed point at each catch baasin. *Newton sites were the test catch basins with SAFL baffles.

2015 Water Resources Report – Minneapolis Park & Recreation Board Page 23-4

th 24. 37 Street Greenway, Iron Enhanced Sand Filters

BACKGROUND

The 37th greenway project is a flood control project that has incorporated innovative stormwater Best Management Practices (BMPs). The project, in North Minneapolis, consisted of several blocks of 37th street being closed off and turned into a bike and pedestrian path. BMP components of the project consist of : large underground vaults, for floodwater retention, iron enhanced sand filters (IESF) to treat both street and alley runoff, and St. Anthony Falls Laboratory (SAFL) baffles to prevent resuspension in catch basin sumps.

Carlos Herrera, of Herrera Environmental Consultants, in Seattle, Washington invented the first iron sand filters used for treating dissolved phosphorus in stormwater. Hee conducted pilot scale testing using full depth filter columns in the late 1980s. The Lakemont Washington Filtration Facility was constructed in phases between 1990 and 1994 when the sand filter, enhanced with a mixture of 95% sand and 5% iron (chopped steel wool), was the first installed in the nation. They were originally called amended sand filters.

The first iron enhanced sand filter (iron filings) built in Minnesota was designed by Barr Engineering and the Ramsey Washington Metro Watershed District and installed in Maplewood Minnesota. The University of Minnesota’s Saint Anthony Falls Laboratory has done further research on these filters and helped to greatly expand their use.

This project consisted of auto-monitoring two IESFs, one draining a street and one draining an alley. The Street Site was located on North Morgan Avenue, and the Alley Site was between North Newton Avenue and Oliver Avenue North, Figure 24-1. The IESFs were constructed as a 3 foot wide trench approximately 30 feet long. A drain tile, acting as an underdrain, is buried the length of the basin. The subsoil was amended with compost on the sides of the basin and it sits over a deeper subsoil of clay. The land use is 50% impervious residential with a dense tree canopy. The drainage area of the 37th & Morgan site is 1.2 acres and the 37th Alley site is 2.3 acres. Note the large shade tree in Figure 23-1 at the 37th and Morgan site.

N. Newton Ave. N. Mor Oliver Ave. N. Street Site Alley Site g an Ave. Ave. an

Shade Tree

Figure 24-1. Map of the 37th Greenway iron enhanced sand filter monitoring sites.

2015 Water Resources Report – Minneapolis Park & Recreation Board Page 24-1 When constructed, the sand filter was amended with 5% iron filings to absorb dissolved phosphorus. When stormwater passes through these filters, iron in the filter should bind with dissolved phosphorus in stormwater, limiting excess nutrients from going downstream. Typically, about 25% to 50% of the phosphorus found in stormwater is dissolved (MPRB/Mpls. NPDES event mean concentrations 2001-2015); therefore, an overall decrease in the amount of phosphorus reaching Crystal Lake downstream should be expected.

The inlet to the iron enhanced filter begins at a 12 inch flared end pipe which discharges into a small cement splash block vault (to capture solids) at one end of the filter, Figure 24-2. The outlet to the filter is a four inch PVC pipe with a threaded cap with a restrictor hole drilled in it intended to slow the drainage and increase the contact time with the iron filings, Figure 24-3.

Figure 24-2. Flared end section and splash block inlet structure to the IESF.

2015 Water Resources Report – Minneapolis Park & Recreation Board Page 24-2

Figure 24-3. Photograph of the 4-inch (white) PVC outlet structure from the IESF.

Both the inlet and outlets were auto sampled and composited the majority of the time. The City, MPCA, and MPRB partnered to do a detailed chemical analysis of select individual storms, where individual bottles were analyzed separately. Single bottle analysis was expected to allow for a better understanding of how these iron enhanced sand filters work throughout the entire event hydrograph.

METHODS

Site Installation Extensive skilled labor including cement masons, plumbers, carpenters, painters, and welders were needed to install monitoring equipment at the 37th Ave Greenway IESF sites. The cement masons were critical due to the extensive concrete hole drilling and anchor placement needed, Figure 24-4 and Figure 24-5.

Figure 24-4. The cement shop drilling access holes and anchors.

2015 Water Resources Report – Minneapolis Park & Recreation Board Page 24-3

Figure 24-5. Mounting sub-surface custom anchor brackets for the sampler enclosure structures.

To monitor the inlet and outlet sites, the inlets were each equipped with one ISCO 2150 datalogger, 2105 interface module, and 2103ci cell phone modem along with a low-profile A/V (area velocity) level probe being placed at the inlet. The 2105 interface module was equipped with a splitter in order to trigger both inlet and outlet samplers simultaneously. Both the inlet and outlet were equipped with ISCO 3700 samplers. The datalogger used the cell phone modem to remotely upload data to the server Monday through Friday. The datalogger could also be remotely called up and programmed to change the pacing or triggers.

Figure 24-6. The 37th Alley Site fully installed. The enclosure structure contains the above ground samplers.

A tipping bucket rain gauge was installed nearby (within 1/4 mile) on a secure rooftop at Folwell Recreation Center. Data was periodically collected throughout the summer from the Hobo datalogger attached to the rain gauge. When precipitation data were missing, it was supplemented with data from the 38th and Bryant Ave S. MPRB South Side Service Center. Precipitation can vary widely over short distances; therefore, having local rain data allowed for more accurate storm event precipitation totals.

2015 Water Resources Report – Minneapolis Park & Recreation Board Page 24-4 Sample Collection

Both the Street runoff site (Morgan Avenue) and Alley runoff site (between Newton and Oliver), the inlet and outlet samplers were each an ISCO 3700 autosampler equipped with 24 one liter bottles, 3/8” inner diameter vinyl tubing, and an intake strainer. The inlet low profile A/V probe and intake strainer were placed just upstream from the flared end outlet with a spring ring. The inlet strainer was placed pointing upstream and offset behind the A/V probe as to not interfere with it. The inlet sampler was triggered at ¾ inches of flow. Both sites used a splitter to trigger inlet and outlet samplers. The datalogger was programmed so once triggered, the inlet sampler would sample only through the storm, but the outlet sampler would continue to run, even if the inlet dropped below the trigger.

At the Street runoff site, the inlet was programmed to flow-pace every 112 cubic feet, taking one flow-paced sample per bottle during the storm. The outlet sampler was programmed to be time-paced, and one sample per bottle every 60 minutes was collected during the storm.

At the Alley runoff site (between Newton and Oliver), the inlet was programmed to flow-pace every 254 cubic feet, taking one flow-paced sample per bottle during the storm. The outlet sampler was programmed to time-pace and one sample per bottle every 22 minutes was collected during the storm.

The goal was to collect 15 storms including five storms where individual bottles could be collected and analyzed separately. Due to the amount of custom work and the amount of problem solving this unique sampling set up required, 15 storms were not collected at all IESF sites in 2015.

RESULTS & DISCUSSION

Sample Collection Table 24-1 shows the events collected and the precipitation, duration, time since last precipitation and intensity of each storm. In 2015, the 37th & Morgan In/Out site collected thirteen paired storm samples. The 37th Alley In/Out collected eight paired storm samples. Most of the storms were composited but a few of the storms had the individual bottles analyzed separately. The 37th & Morgan In/Out site collected five individual bottle storms and at the 37th Alley In/Out site two individual bottle storms were collected. It was planned that individual bottle analysis would allow a better understanding of what was chemically occurring (with phosphorus, solids, and iron) through time during a storm.

Five precipitation events required the South Side Service Center rain gauge, at 38th and Bryant Ave S, to be used to supplement missing precipitation data from the Folwell rain gauge.

2015 Water Resources Report – Minneapolis Park & Recreation Board Page 24-5 Table 24-1. The 2015 precipitation events captured at the 37th & Morgan and 37th Alley IESF sites. A precipitation event was defined as a storm greater than 0.10 inches, separated by eight hours or more from other precipitation. Time since 37th & 37th & 37th 37th Precip Duration last Precip. Intensity Morgan Morgan Alley Alley Start Date/Time End Date/Time (inches) (hours) (hours) inch/hr In Out In Out 06/11/2015 4:45 6/11/2015 15:45 0.31* 11 101 0.03 Composite Composite 06/20/2015 5:45 6/20/2015 8:15 0.39* 2.5 64 0.16 Composite Composite Composite Composite 06/22/2015 7:00 6/22/2015 16:15 1.52* 9.25 47 0.16 Composite Composite 06/26/2015 17:45 6/26/2015 17:45 0.17* 0.25 98 0.68 Composite Composite 7/6/2015 0:52 7/6/2015 13:11 0.34 12 683 0.03 Composite Composite 07/12/2015 23:30 7/13/2015 10:00 1.65* 10.5 155 0.16 Ind Btl. Ind Btl. Ind Btl. Ind Btl. 7/18/2015 0:53 7/18/2015 10:53 0.11 10 276 0.01 Composite Composite 7/28/2015 6:18 7/28/2015 11:05 0.21 5 92 0.04 Ind Btl. Ind Btl. Ind Btl. Ind Btl. 8/6/2015 9:48 8/7/2015 9:20 0.23 24 215 0.01 Composite Composite Composite Composite 8/9/2015 0:00 Non Precip Event Composite Composite Composite Composite 8/18/2015 11:10 8/19/2015 10:12 0.35 23 266 0.02 Composite Composite Composite Composite 9/9/2015 12:16 9/10/2015 6:39 0.13 18 68 0.01 Composite Composite 9/17/2015 4:59 9/17/2015 22:17 0.21 17 166 0.01 Ind Btl. Ind Btl. 9/23/2015 18:10 9/24/2015 15:10 0.10 21 115 0.005 Ind Btl. Ind Btl. 10/27/2015 18:45 10/29/2015 6:13 0.57 35 81 0.02 Ind Btl. Ind Btl. * SSSC precip data

The event of 8/9/15 appeared to be a non-precipitation event. No record of precipitation at Folwell, the NWS MSP airport, or the MPRB South Side Service Center was found.

Event Data

Table 24-2 shows the 2015 37th & Morgan and 37th Alley IESF chemistry data. Data that are underlined failed that parameter during the blind monthly QAQC standards from internal MPRB testing. The sample type column indicates if the sample was a composite or an individual bottle event (Indv Btl). Individual bottle events were when each bottle was analyzed separately. In Table 24-2, the shaded rows separate storm events. The parameters collected were: TP, TDP, Ortho-P, TSS, and Fe. There was a limited amount of TP and TSS water chemistry collected. The additional data proved useful in answering IESF functionality questions.

2015 Water Resources Report – Minneapolis Park & Recreation Board Page 24-6

Table 24-2. The 2015 37th & Morgan Inlet Iron Enhanced Sand Filter data. Date Sampled Time Site Location Sample TP TDP Ortho-P TKN NH3 NO3NO2 Cl Hardness TSS VSS TDS cBOD Sulfate Sp.Cond. pH Cu Pb Zn Fe Type mg/L mg/L mg/L mg/L mg/L mg/L mg/L mg/L mg/L mg/L mg/L mg/L mg/L uhmos std units ug/L ug/L ug/L ug/L 6/11/2015 8:24 37th & Morgan In Composite 0.956 0.575 0.553 13 1000 6/20/2015 7:04 37th & Morgan In Composite 0.872 0.273 0.341 130 2300 6/22/2015 9:04 37th & Morgan In Composite 0.415 0.129 0.142 62 1000 6/26/2015 17:45 37th & Morgan In Composite 0.965 0.186 0.542 119 4800 6/28/2015 1:15 37th & Morgan In #1 Indv Btl. 0.680 0.089 0.171 75 2600 6/28/2015 17:05 37th & Morgan In #2 Indv Btl. 0.387 0.070 0.134 77 1300 7/12/2015 23:14 37th & Morgan In #1 Indv Btl. 2.16 0.701 0.692 367 9500 7/13/2015 0:22 37th & Morgan In #2 Indv Btl. 0.367 0.032 0.079 116 2300 7/13/2015 0:25 37th & Morgan In #3 Indv Btl. 0.865 0.062 0.182 367 9300 7/13/2015 0:27 37th & Morgan In #4 Indv Btl. 0.278 0.011 0.035 67 1100 7/13/2015 0:44 37th & Morgan In #5 Indv Btl. 0.211 0.014 0.037 25 400 7/13/2015 1:02 37th & Morgan In #6 Indv Btl. 0.266 0.021 0.038 22 370 7/13/2015 1:20 37th & Morgan In #7 Indv Btl. 0.211 0.017 0.036 16 300 7/13/2015 1:40 37th & Morgan In #8 Indv Btl. 0.167 0.017 0.034 18 190 7/13/2015 2:12 37th & Morgan In #9 Indv Btl. 0.187 0.012 0.031 24 140 7/18/2015 4:49 37th & Morgan In Composite 0.199 0.107 0.106 15 230 7/28/2015 6:38 37th & Morgan In #2 Indv Btl. 0.342 0.153 0.193 35 600 7/28/2015 6:42 37th & Morgan In #4 Indv Btl. 0.293 0.132 0.172 53 640 7/28/2015 6:47 37th & Morgan In #6 Indv Btl. 0.887 0.336 0.214 26 1600 7/28/2015 7:04 37th & Morgan In #8 Indv Btl. 0.229 0.109 0.137 32 570 7/28/2015 7:28 37th & Morgan In #10 Indv Btl. 0.134 0.087 0.084 22 440 7/28/2015 7:53 37th & Morgan In #12 Indv Btl. 0.109 0.066 0.07 7 110 7/28/2015 8:17 37th & Morgan In #14 Indv Btl. 0.133 0.059 0.07 7 180 7/28/2015 8:42 37th & Morgan In #16 Indv Btl. 0.144 0.077 0.072 7 210 7/28/2015 9:19 37th & Morgan In #18 Indv Btl. 0.149 0.063 0.072 4 160 7/28/2015 10:05 37th & Morgan In #20 Indv Btl. 0.229 0.127 0.127 9 170 8/7/2015 1:16 37th & Morgan In Composite 0.433 0.077 0.119 55 6.5 490 8/9/2015 14:42 37th & Morgan In Composite 0.425 0.187 0.187 17 530 8/18/2015 21:34 37th & Morgan In Composite 0.132 0.061 0.068 9 140 9/10/2015 5:29 37th & Morgan In Composite 0.12 0.098 0.07 1.39 0.816 0.231 <2.0 30.0 11 5 10 6 <5.0 46 7.3 <5.00 <3.00 20 200 9/17/2015 6:41 37th & Morgan In #1 Indv Btl. 0.314 0.134 0.153 81 400 9/17/2015 6:52 37th & Morgan In #2 Indv Btl. 0.204 0.143 0.119 32 170 9/17/2015 7:12 37th & Morgan In #3 Indv Btl. 0.200 0.130 0.107 22 200 9/24/2015 4:27 37th &Morgan In #1 Indv Btl. 0.317 0.252 0.143 10 500 9/24/2015 6:46 37th & Morgan In #2 Indv Btl. 0.261 0.183 0.119 19 290 9/24/2015 7:09 37th & Morgan In #3 Indv Btl. 0.209 0.157 0.105 10 210 10/27/2015 19:00 37th & Morgan In #1 Indv Btl. 2.62 2.29 2.68 25 620 10/27/2015 21:20 37th & Morgan In #2 Indv Btl. 2.37 1.99 2.10 53 210 10/27/2015 21:42 37th & Morgan In #3 Indv Btl. 2.11 1.91 1.84 30 25 10/27/2015 22:03 37th & Morgan In #4 Indv Btl. 2.00 1.79 1.69 26 25 10/27/2015 22:25 37th & Morgan In #5 Indv Btl. 1.91 1.37 1.43 25 25 10/27/2015 22:46 37th & Morgan In #6 Indv Btl. 1.46 1.35 1.27 20 25 10/27/2015 23:08 37th & Morgan In #7 Indv Btl. 1.39 1.25 1.20 18 25 10/27/2015 23:31 37th & Morgan In #8 Indv Btl. 1.26 1.07 0.963 13 25 10/27/2015 23:54 37th & Morgan In #9 Indv Btl. 1.17 1.00 0.901 19 25 10/28/2015 0:18 37th & Morgan In #10 Indv Btl. 1.07 0.902 0.811 17 25 10/28/2015 0:40 37th & Morgan In #11 Indv Btl. 0.989 0.819 0.731 13 25 10/28/2015 1:01 37th & Morgan In #12 Indv Btl. 0.905 0.762 0.676 15 25 10/28/2015 1:24 37th & Morgan In #13 Indv Btl. 0.872 0.735 0.625 3 25 10/28/2015 1:52 37th & Morgan In #14 Indv Btl. 0.771 0.706 0.583 9 25 10/28/2015 2:20 37th & Morgan In #15 Indv Btl. 0.838 0.649 0.539 11 25 10/28/2015 2:49 37th & Morgan In #16 Indv Btl. 0.704 0.691 0.516 4 25 10/28/2015 3:23 37th & Morgan In #17 Indv Btl. 0.721 0.632 0.500 10 25 10/28/2015 4:11 37th & Morgan In #18 Indv Btl. 0.771 0.642 0.493 7 25 10/28/2015 4:56 37th & Morgan In #19 Indv Btl. 0.805 0.644 0.484 5 25 10/28/2015 5:10 37th & Morgan In #20 Indv Btl. 0.704 0.602 0.465 8 25 10/28/2015 5:30 37th & Morgan In #21 Indv Btl. 0.704 0.564 0.448 16 25 2015 Water Resources Report – Minneapolis Park & Recreation Board Page 24-7

Table 24-2 (cont.). The 2015 37th & Morgan Outlet Iron Enhanced Sand Filter data.

Date Sampled Time Site Location Sample TP TDP Ortho-P TKN NH3 NO3NO2 Cl Hardness TSS VSS TDS cBOD Sulfate Sp.Cond. pH Cu Pb Zn Fe Type mg/L mg/L mg/L mg/L mg/L mg/L mg/L mg/L mg/L mg/L mg/L mg/L mg/L uhmos std units ug/L ug/L ug/L ug/L 6/11/2015 13:36 37th & Morgan Out Composite 0.364 0.222 0.243 52 3700 6/20/2015 13:27 37th & Morgan Out Composite 0.262 0.121 0.118 8 2300 6/26/2015 23:15 37th & Morgan Out Composite 0.286 0.044 0.115 18 8300 7/12/2015 18:29 37th & Morgan Out #2 Indv Btl. 0.254 0.192 0.218 1 490 7/12/2015 23:14 37th & Morgan Out #3 Indv Btl. 0.251 0.205 0.234 5 430 7/13/2015 0:12 37th & Morgan Out #4 Indv Btl. 0.257 0.194 0.222 0 340 7/13/2015 1:12 37th & Morgan Out #5 Indv Btl. 0.255 0.182 0.248 5 1500 7/13/2015 2:12 37th & Morgan Out #6 Indv Btl. 0.218 0.16 0.212 3 2000 7/13/2015 3:12 37th & Morgan Out #7 Indv Btl. 0.210 0.149 0.198 0 2600 7/13/2015 4:12 37th & Morgan Out #8 Indv Btl. 0.195 0.16 0.188 4 3300 7/13/2015 5:12 37th & Morgan Out #9 Indv Btl. 0.194 0.128 0.178 1 3800 7/13/2015 6:12 37th & Morgan Out #10 Indv Btl. 0.191 0.117 0.185 2 4200 7/13/2015 37th & Morgan Out Composite 0.236 0.167 0.194 2 580 7/18/2015 2:52 37th & Morgan Out Composite 0.322 0.146 0.244 11 4600 7/28/2015 6:56 37th & Morgan Out #2 Indv Btl. 0.273 0.244 0.255 2 580 7/28/2015 7:56 37th & Morgan Out #3 Indv Btl. 0.272 0.253 0.264 2 470 7/28/2015 8:56 37th & Morgan Out #4 Indv Btl. 0.294 0.245 0.260 2 420 7/28/2015 9:56 37th & Morgan Out #5 Indv Btl. 0.371 0.267 0.278 2 520 7/28/2015 10:56 37th & Morgan Out #6 Indv Btl. 0.281 0.209 0.246 4 2500 7/28/2015 37th & Morgan Out Composite 0.248 0.173 0.210 2 900 8/7/2015 9:21 37th Morgan - Out Composite 0.269 0.127 0.175 9 7.3 2500 8/10/2015 8:36 37th Morgan Out Composite 0.395 0.248 0.285 11 4900 8/19/2015 4:30 37th Morgan Out Composite 0.203 0.147 0.169 2 980 9/10/2015 8:22 37th Morgan Out Composite 0.209 0.140 0.189 1.01 <0.500 0.107 <2.0 100 5 3 140 4 8 225 6.9 <5.00 <3.00 <20.0 2000 9/17/2015 6:02 37th Morgan Out #2 Indv Btl. 0.293 0.168 0.205 5 2300 9/17/2015 7:02 37th Morgan Out #3 Indv Btl. 0.187 0.142 0.148 1 300 9/17/2015 8:02 37th Morgan Out #4 Indv Btl. 0.231 0.163 0.191 1 1400 9/17/2015 9:02 37th Morgan Out #5 Indv Btl. 0.219 0.169 0.197 1 2200 9/17/2015 10:02 37th Morgan Out #6 Indv Btl. 0.227 0.132 0.200 3 2800 9/24/2015 3:23 37th Morgan Out #2 Indv Btl. 0.285 0.183 0.168 8 2000 9/24/2015 4:23 37th Morgan Out #3 Indv Btl. 0.267 0.210 0.205 6 1200 9/24/2015 5:23 37th Morgan Out #4 Indv Btl. 0.241 0.188 0.184 4 790 9/24/2015 6:23 37th Morgan Out #5 Indv Btl. 0.259 0.199 0.213 4 1300 9/24/2015 7:23 37th Morgan Out #6 Indv Btl. 0.190 0.158 0.148 3 400 9/24/2015 8:23 37th Morgan Out #7 Indv Btl. 0.206 0.172 0.181 3 1100 9/24/2015 37th Morgan Out Composite 0.224 0.024 0.192 14 5100 10/27/2015 18:55 37th Morgan Out #1 Indv Btl. 1.54 1.33 1.40 15 1700 10/27/2015 19:55 37th Morgan Out #2 Indv Btl. 1.86 1.72 1.95 18 1300 10/27/2015 20:55 37th Morgan Out #3 Indv Btl. 1.76 1.72 1.70 13 1000 10/27/2015 21:55 37th Morgan Out #4 Indv Btl. 1.48 1.40 1.35 9 850 10/27/2015 22:55 37th Morgan Out #5 Indv Btl. 1.20 1.20 1.11 4 830 10/27/2015 23:55 37th Morgan Out #6 Indv Btl. 0.990 1.03 0.903 6 710 10/28/2015 0:55 37th Morgan Out #7 Indv Btl. 0.869 0.886 0.773 2 700 10/28/2015 1:55 37th Morgan Out #8 Indv Btl. 0.855 0.772 0.711 3 750 10/28/2015 2:55 37th Morgan Out #9 Indv Btl. 0.721 0.731 0.642 2 800 10/28/2015 3:55 37th Morgan Out #10 Indv Btl. 0.708 0.637 0.688 6 800 10/28/2015 4:55 37th Morgan Out #11 Indv Btl. 0.772 0.657 0.596 8 650 10/28/2015 5:55 37th Morgan Out #12 Indv Btl. 0.721 0.684 0.574 2 690 10/28/2015 6:55 37th Morgan Out #13 Indv Btl. 0.725 0.557 0.541 6 790 10/28/2015 7:55 37th Morgan Out #14 Indv Btl. 0.704 0.537 0.502 6 820 10/28/2015 8:55 37th Morgan Out #15 Indv Btl. 0.564 0.520 0.521 9 970 10/28/2015 9:55 37th Morgan Out #16 Indv Btl. 0.607 0.473 0.505 9 1100 10/28/2015 10:55 37th Morgan Out #17 Indv Btl. 0.537 0.507 0.574 8 1200 2015 Water Resources Report – Minneapolis Park & Recreation Board Page 24-8

Table 24-2 (cont). The 2015 37th Alley Inlet/Outlet Iron Enhanced Sand Filter data. Date Sampled Time Site Location Sample TP TDP Ortho-P TKN NH3 NO3NO2 Cl Hardness TSS VSS TDS cBOD Sulfate Sp.Cond. pH Cu Pb Zn Fe Type mg/L mg/L mg/L mg/L mg/L mg/L mg/L mg/L mg/L mg/L mg/L mg/L mg/L uhmos std units ug/L ug/L ug/L ug/L 6/20/2015 6:00 37th Alley In Composite 1.40 0.500 0.536 162 3100 6/22/2015 8:41 37th Alley In Composite 0.396 0.113 0.153 45 1100 7/6/2015 0:41 37th Alley In Composite 0.387 0.139 0.226 230 430 7/12/2015 23:18 37th Alley In #1 Indv Btl. 0.775 0.098 0.310 625 6700 7/12/2015 23:21 37th Alley In #2 Indv Btl. 0.580 0.113 0.201 306 4100 7/12/2015 23:25 37th Alley In #3 Indv Btl. 0.513 0.147 0.236 234 2900 7/12/2015 23:29 37th Alley In #4 Indv Btl. 0.415 0.130 0.197 155 2100 7/12/2015 23:33 37th Alley In #5 Indv Btl. 0.322 0.106 0.171 114 1700 7/12/2015 23:45 37th Alley In #6 Indv Btl. 0.259 0.089 0.147 70 1100 7/13/2015 0:20 37th Alley In #7 Indv Btl. 0.166 0.071 0.113 25 430 7/28/2015 6:30 37th Alley In #1 Indv Btl. 0.714 0.261 0.380 201 2700 7/28/2015 6:40 37th Alley In #2 Indv Btl. 0.443 0.215 0.277 149 1800 7/28/2015 6:45 37th Alley In #3 Indv Btl. 0.391 0.179 0.229 280 2900 7/28/2015 6:50 37th Alley In #4 Indv Btl. 0.353 0.144 0.191 175 1400 7/28/2015 6:56 37th Alley In #5 Indv Btl. 0.381 0.164 0.225 106 1500 7/28/2015 7:00 37th Alley In #6 Indv Btl. 0.320 0.177 0.219 59 970 8/6/2015 15:12 37th Alley In Composite 0.672 0.212 0.283 118 6.7 2000 8/9/2015 14:21 37th Alley In Composite 0.335 0.144 0.163 26 570 8/18/2015 14:35 37th Alley In Composite 0.203 0.113 0.127 19 370

6/20/2015 7:27 37th Alley Out Composite 0.332 0.277 0.269 2 160 6/22/2015 10:01 37th Alley Out Composite 0.341 0.309 0.278 7 98 7/6/2015 9:22 37th Alley Out Composite 0.214 0.160 0.154 10 250 7/12/2015 23:21 37th Alley Out #1 Indv Btl. 0.180 0.063 0.061 5 230 7/12/2015 23:43 37th Alley Out #2 Indv Btl. 0.111 0.067 0.079 1 320 7/13/2015 0:05 37th Alley Out #3 Indv Btl. 0.137 0.107 0.113 4 270 7/13/2015 0:27 37th Alley Out #4 Indv Btl. 0.136 0.123 0.129 6 270 7/13/2015 0:49 37th Alley Out #5 Indv Btl. 0.150 0.128 0.146 2 260 7/13/2015 1:11 37th Alley Out #6 Indv Btl. 0.165 0.151 0.148 1 250 7/28/2015 7:16 37th Alley Out #1 Indv Btl. 0.176 0.094 0.131 5 250 7/28/2015 8:00 37th Alley Out #3 Indv Btl. 0.184 0.149 0.160 4 280 7/28/2015 8:44 37th Alley Out #5 Indv Btl. 0.276 0.169 0.192 11 320 7/28/2015 9:28 37th Alley Out #7 Indv Btl. 0.498 0.420 0.368 5 320 7/28/2015 10:12 37th Alley Out #9 Indv Btl. 0.498 0.420 0.379 8 300 7/28/2015 10:56 37th Alley Out #11 Indv Btl. 0.480 0.402 0.373 5 260 7/28/2015 11:40 37th Alley Out #13 Indv Btl. 0.479 0.455 0.368 4 270 8/6/2015 16:12 37th Alley Out Composite 0.388 0.278 0.272 7 7.2 190 8/9/2015 15:03 37th Alley Out Composite 0.404 0.323 0.312 6 120 8/18/2015 19:51 37th Alley Out Composite 0.340 0.293 0.283 2 140

2015 Water Resources Report – Minneapolis Park & Recreation Board Page 24-9

Table 24-3 shows the 2015 Inlet/Outlet paired storms for both 37th & Morgan and 37th Alley sites. The phosphorus, TDP, Ortho P, TSS, and Fe results can be compared. The geometric mean and median were calculated for the storms with individual bottles collected so one value can be used for comparison with the composite samples. The geometric mean was calculated because it is believed to be the best statistical tool for comparison purposes of stormwater data. Individual storms are separated by shading of the rows.

2015 Water Resources Report – Minneapolis Park & Recreation Board Page 24-10 Table 24-3. 37th & Morgan Inlet/Outlet paired storm comparison of composites and individual bottles during storm. Date Site Sample TP TDP Ortho-P TSS Fe Sampled/Time Location Type mg/L mg/L mg/L mg/L ug/L 06/11/15 08:24 37th & Morgan In Composite 0.956 0.575 0.553 13 1000 06/11/15 13:36 37th & Morgan Out Composite 0.364 0.222 0.243 52 3700 06/20/15 07:04 37th & Morgan In Composite 0.872 0.273 0.341 130 2300 06/20/15 13:27 37th & Morgan Out Composite 0.262 0.121 0.118 8 2300 06/26/15 17:45 37th & Morgan In Composite 0.965 0.186 0.542 119 4800 06/26/15 23:15 37th & Morgan Out Composite 0.286 0.044 0.115 18 8300 07/12/15 23:14 37th & Morgan In #1 Indv Btl. 2.16 0.701 0.692 367 9500 07/13/15 00:22 37th & Morgan In #2 Indv Btl. 0.367 0.032 0.079 116 2300 07/13/15 00:25 37th & Morgan In #3 Indv Btl. 0.865 0.062 0.182 367 9300 07/13/15 00:27 37th & Morgan In #4 Indv Btl. 0.278 0.011 0.035 67 1100 07/13/15 00:44 37th & Morgan In #5 Indv Btl. 0.211 0.014 0.037 25 400 07/13/15 01:02 37th & Morgan In #6 Indv Btl. 0.266 0.021 0.038 22 370 07/13/15 01:20 37th & Morgan In #7 Indv Btl. 0.211 0.017 0.036 16 300 07/13/15 01:40 37th & Morgan In #8 Indv Btl. 0.167 0.017 0.034 18 190 07/13/15 02:12 37th & Morgan In #9 Indv Btl. 0.187 0.012 0.031 24 140 37th & Morgan In GEO MEAN 0.346 0.029 0.064 54 862 37th & Morgan In MEDIAN 0.266 0.017 0.037 25 400 07/12/15 18:29 37th & Morgan Out #2 Indv Btl. 0.254 0.192 0.218 1 490 07/12/15 23:14 37th & Morgan Out #3 Indv Btl. 0.251 0.205 0.234 5 430 07/13/15 00:12 37th & Morgan Out #4 Indv Btl. 0.257 0.194 0.222 0 340 07/13/15 01:12 37th & Morgan Out #5 Indv Btl. 0.255 0.182 0.248 5 1500 07/13/15 02:12 37th & Morgan Out #6 Indv Btl. 0.218 0.16 0.212 3 2000 07/13/15 03:12 37th & Morgan Out #7 Indv Btl. 0.210 0.149 0.198 0 2600 07/13/15 04:12 37th & Morgan Out #8 Indv Btl. 0.195 0.160 0.188 4 3300 07/13/15 05:12 37th & Morgan Out #9 Indv Btl. 0.194 0.128 0.178 1 3800 07/13/15 06:12 37th & Morgan Out #10 Indv Btl. 0.191 0.117 0.185 2 4200 37th & Morgan Out GEO MEAN 0.223 0.163 0.208 2 1456 37th & Morgan Out MEDIAN 0.218 0.160 0.212 2 2000 07/18/15 04:49 37th & Morgan In Composite 0.199 0.107 0.106 15 230 07/18/15 02:52 37th & Morgan Out Composite 0.322 0.146 0.244 11 4600 07/28/15 06:38 37th & Morgan In #2 Indv Btl. 0.342 0.153 0.193 35 600 07/28/15 06:42 37th & Morgan In #4 Indv Btl. 0.293 0.132 0.172 53 640 07/28/15 06:47 37th & Morgan In #6 Indv Btl. 0.887 0.336 0.214 26 1600 07/28/15 07:04 37th & Morgan In #8 Indv Btl. 0.229 0.109 0.137 32 570 07/28/15 07:28 37th & Morgan In #10 Indv Btl. 0.134 0.087 0.084 22 440 07/28/15 07:53 37th & Morgan In #12 Indv Btl. 0.109 0.066 0.070 7 110 07/28/15 08:17 37th & Morgan In #14 Indv Btl. 0.133 0.059 0.070 7 180 07/28/15 08:42 37th & Morgan In #16 Indv Btl. 0.144 0.077 0.072 7 210 07/28/15 09:19 37th & Morgan In #18 Indv Btl. 0.149 0.063 0.072 4 160 07/28/15 10:05 37th & Morgan In #20 Indv Btl. 0.229 0.127 0.127 9 170 37th & Morgan In GEO MEAN 0.213 0.104 0.110 15 334 37th & Morgan In MEDIAN 0.189 0.098 0.106 15 325 07/28/15 06:56 37th & Morgan Out #2 Indv Btl. 0.273 0.244 0.255 2 580 07/28/15 07:56 37th & Morgan Out #3 Indv Btl. 0.272 0.253 0.264 2 470 07/28/15 08:56 37th & Morgan Out #4 Indv Btl. 0.294 0.245 0.260 2 420 07/28/15 09:56 37th & Morgan Out #5 Indv Btl. 0.371 0.267 0.278 2 520 07/28/15 10:56 37th & Morgan Out #6 Indv Btl. 0.281 0.209 0.246 4 2500 37th & Morgan Out GEO MEAN 0.296 0.243 0.260 2 683 37th & Morgan Out MEDIAN 0.281 0.245 0.260 2 520 08/07/15 01:16 37th & Morgan In Composite 0.433 0.077 0.119 55 490 08/07/15 09:21 37th Morgan Out Composite 0.269 0.127 0.175 9 2500 Non-precipitation event 08/09/15 14:42 37th & Morgan In Composite 0.425 0.187 0.187 17 530 08/10/15 08:36 37th Morgan Out Composite 0.395 0.248 0.285 11 4900 08/18/15 21:34 37th & Morgan In Composite 0.132 0.061 0.068 9 140 08/19/15 04:30 37th Morgan Out Composite 0.203 0.147 0.169 2 980 09/10/15 05:29 37th & Morgan In Composite 0.120 0.098 0.070 11 200 09/10/15 08:22 37th Morgan Out Composite 0.209 0.140 0.189 5 2000

2015 Water Resources Report – Minneapolis Park & Recreation Board Page 24-11 Table 24-3 (cont). 37th & Morgan In/Out paired storm comparison of composites and individual bottles during storm. Date Site Sample TP TDP Ortho-P TSS Fe Sampled/Time Location Type mg/L mg/L mg/L mg/L ug/L 09/17/15 06:41 37th & Morgan In #1 Indv Btl. 0.314 0.134 0.153 81 400 09/17/15 06:52 37th & Morgan In #2 Indv Btl. 0.204 0.143 0.119 32 170 09/17/15 07:12 37th & Morgan In #3 Indv Btl. 0.200 0.130 0.107 22 200 37th & Morgan In GEO MEAN 0.234 0.136 0.125 39 239 37th & Morgan In MEDIAN 0.204 0.134 0.119 32 200 09/17/15 06:02 37th Morgan Out #2 Indv Btl. 0.293 0.168 0.205 5 2300 09/17/15 07:02 37th Morgan Out #3 Indv Btl. 0.187 0.142 0.148 1 300 09/17/15 08:02 37th Morgan Out #4 Indv Btl. 0.231 0.163 0.191 1 1400 09/17/15 09:02 37th Morgan Out #5 Indv Btl. 0.219 0.169 0.197 1 2200 09/17/15 10:02 37th Morgan Out #6 Indv Btl. 0.227 0.132 0.200 3 2800 37th & Morgan Out GEO MEAN 0.229 0.154 0.187 2 1429 37th & Morgan Out MEDIAN 0.227 0.163 0.197 1 2200 09/24/15 04:27 37th &Morgan In #1 Indv Btl. 0.317 0.252 0.143 10 500 09/24/15 06:46 37th & Morgan In #2 Indv Btl. 0.261 0.183 0.119 19 290 09/24/15 07:09 37th & Morgan In #3 Indv Btl. 0.209 0.157 0.105 10 210 37th & Morgan In GEO MEAN 0.259 0.193 0.121 12 312 37th & Morgan In MEDIAN 0.261 0.183 0.119 10 290 09/24/15 03:23 37th Morgan Out #2 Indv Btl. 0.285 0.183 0.168 8 2000 09/24/15 04:23 37th Morgan Out #3 Indv Btl. 0.267 0.210 0.205 6 1200 09/24/15 05:23 37th Morgan Out #4 Indv Btl. 0.241 0.188 0.184 4 790 09/24/15 06:23 37th Morgan Out #5 Indv Btl. 0.259 0.199 0.213 4 1300 09/24/15 07:23 37th Morgan Out #6 Indv Btl. 0.190 0.158 0.148 3 400 09/24/15 08:23 37th Morgan Out #7 Indv Btl. 0.206 0.172 0.181 3 1100 37th & Morgan Out GEO MEAN 0.239 0.184 0.182 4 1014 37th & Morgan Out MEDIAN 0.250 0.186 0.183 4 1150 10/27/15 19:00 37th & Morgan In #1 Indv Btl. 2.62 2.29 2.68 25 620 10/27/15 21:20 37th & Morgan In #2 Indv Btl. 2.37 1.99 2.10 53 210 10/27/15 21:42 37th & Morgan In #3 Indv Btl. 2.11 1.91 1.84 30 25 10/27/15 22:03 37th & Morgan In #4 Indv Btl. 2.00 1.79 1.69 26 25 10/27/15 22:25 37th & Morgan In #5 Indv Btl. 1.91 1.37 1.43 25 25 10/27/15 22:46 37th & Morgan In #6 Indv Btl. 1.46 1.35 1.27 20 25 10/27/15 23:08 37th & Morgan In #7 Indv Btl. 1.39 1.25 1.20 18 25 10/27/15 23:31 37th & Morgan In #8 Indv Btl. 1.26 1.07 0.963 13 25 10/27/15 23:54 37th & Morgan In #9 Indv Btl. 1.17 1.00 0.901 19 25 10/28/15 00:18 37th & Morgan In #10 Indv Btl. 1.07 0.902 0.811 17 25 10/28/15 00:40 37th & Morgan In #11 Indv Btl. 0.989 0.819 0.731 13 25 10/28/15 01:01 37th & Morgan In #12 Indv Btl. 0.905 0.762 0.676 15 25 10/28/15 01:24 37th & Morgan In #13 Indv Btl. 0.872 0.735 0.625 3 25 10/28/15 01:52 37th & Morgan In #14 Indv Btl. 0.771 0.706 0.583 9 25 10/28/15 02:20 37th & Morgan In #15 Indv Btl. 0.838 0.649 0.539 11 25 10/28/15 02:49 37th & Morgan In #16 Indv Btl. 0.704 0.691 0.516 4 25 10/28/15 03:23 37th & Morgan In #17 Indv Btl. 0.721 0.632 0.500 10 25 10/28/15 04:11 37th & Morgan In #18 Indv Btl. 0.771 0.642 0.493 7 25 10/28/15 04:56 37th & Morgan In #19 Indv Btl. 0.805 0.644 0.484 5 25 10/28/15 05:10 37th & Morgan In #20 Indv Btl. 0.704 0.602 0.465 8 25 10/28/15 05:30 37th & Morgan In #21 Indv Btl. 0.704 0.564 0.448 16 25 37th & Morgan In GEO MEAN 1.13 0.962 0.850 13 32 37th & Morgan In MEDIAN 0.989 0.819 0.731 15 25 10/27/15 18:55 37th Morgan Out #1 Indv Btl. 1.54 1.33 1.40 15 1700 10/27/15 19:55 37th Morgan Out #2 Indv Btl. 1.86 1.72 1.95 18 1300 10/27/15 20:55 37th Morgan Out #3 Indv Btl. 1.76 1.72 1.70 13 1000 10/27/15 21:55 37th Morgan Out #4 Indv Btl. 1.48 1.40 1.35 9 850 10/27/15 22:55 37th Morgan Out #5 Indv Btl. 1.20 1.20 1.11 4 830 10/27/15 23:55 37th Morgan Out #6 Indv Btl. 0.990 1.03 0.903 6 710 10/28/15 00:55 37th Morgan Out #7 Indv Btl. 0.869 0.886 0.773 2 700 10/28/15 01:55 37th Morgan Out #8 Indv Btl. 0.855 0.772 0.711 3 750 10/28/15 02:55 37th Morgan Out #9 Indv Btl. 0.721 0.731 0.642 2 800 10/28/15 03:55 37th Morgan Out #10 Indv Btl. 0.708 0.637 0.688 6 800 10/28/15 04:55 37th Morgan Out #11 Indv Btl. 0.772 0.657 0.596 8 650 10/28/15 05:55 37th Morgan Out #12 Indv Btl. 0.721 0.684 0.574 2 690 10/28/15 06:55 37th Morgan Out #13 Indv Btl. 0.725 0.557 0.541 6 790 10/28/15 07:55 37th Morgan Out #14 Indv Btl. 0.704 0.537 0.502 6 820 10/28/15 08:55 37th Morgan Out #15 Indv Btl. 0.564 0.520 0.521 9 970 10/28/15 09:55 37th Morgan Out #16 Indv Btl. 0.607 0.473 0.505 9 1100 10/28/15 10:55 37th Morgan Out #17 Indv Btl. 0.537 0.507 0.574 8 1200 37th & Morgan Out GEO MEAN 0.903 0.823 0.797 6 890 37th & Morgan Out MEDIAN 0.772 0.731 0.688 6 820

2015 Water Resources Report – Minneapolis Park & Recreation Board Page 24-12 Table 24-3 (cont.). 37th Alley In/Out paired storm comparison of composites and individual bottles during storm. Date Site Sample TP TDP Ortho-P TSS Fe Sampled/Time Location Type mg/L mg/L mg/L mg/L ug/L 06/20/15 06:00 37th Alley In Composite 1.40 0.500 0.536 162 3100 06/20/15 07:27 37th Alley Out Composite 0.332 0.277 0.269 2 160 06/22/15 08:41 37th Alley In Composite 0.396 0.113 0.153 45 1100 06/22/15 10:01 37th Alley Out Composite 0.341 0.309 0.278 7 98 07/06/15 00:41 37th Alley In Composite 0.387 0.139 0.226 230 430 07/06/15 09:22 37th Alley Out Composite 0.214 0.160 0.154 10 250 07/12/15 23:18 37th Alley In #1 Indv Btl. 0.775 0.098 0.310 625 6700 07/12/15 23:21 37th Alley In #2 Indv Btl. 0.580 0.113 0.201 306 4100 07/12/15 23:25 37th Alley In #3 Indv Btl. 0.513 0.147 0.236 234 2900 07/12/15 23:29 37th Alley In #4 Indv Btl. 0.415 0.130 0.197 155 2100 07/12/15 23:33 37th Alley In #5 Indv Btl. 0.322 0.106 0.171 114 1700 07/12/15 23:45 37th Alley In #6 Indv Btl. 0.259 0.089 0.147 70 1100 07/13/15 00:20 37th Alley In #7 Indv Btl. 0.166 0.071 0.113 25 430 37th & Alley In GEO MEAN 0.388 0.105 0.188 145 2014 37th & Alley In MEDIAN 0.415 0.106 0.197 155 2100 07/12/15 23:21 37th Alley Out #1 Indv Btl. 0.180 0.063 0.061 5 230 07/12/15 23:43 37th Alley Out #2 Indv Btl. 0.111 0.067 0.079 1 320 07/13/15 00:05 37th Alley Out #3 Indv Btl. 0.137 0.107 0.113 4 270 07/13/15 00:27 37th Alley Out #4 Indv Btl. 0.136 0.123 0.129 6 270 07/13/15 00:49 37th Alley Out #5 Indv Btl. 0.150 0.128 0.146 2 260 07/13/15 01:11 37th Alley Out #6 Indv Btl. 0.165 0.151 0.148 1 250 37th & Alley Out GEO MEAN 0.145 0.101 0.107 3 265 37th & Alley Out MEDIAN 0.144 0.115 0.121 3 265 07/28/15 06:30 37th Alley In #1 Indv Btl. 0.714 0.261 0.380 201 2700 07/28/15 06:40 37th Alley In #2 Indv Btl. 0.443 0.215 0.277 149 1800 07/28/15 06:45 37th Alley In #3 Indv Btl. 0.391 0.179 0.229 280 2900 07/28/15 06:50 37th Alley In #4 Indv Btl. 0.353 0.144 0.191 175 1400 07/28/15 06:56 37th Alley In #5 Indv Btl. 0.381 0.164 0.225 106 1500 07/28/15 07:00 37th Alley In #6 Indv Btl. 0.320 0.177 0.219 59 970 37th & Alley In GEO MEAN 0.418 0.186 0.247 145 1750 37th & Alley In MEDIAN 0.386 0.178 0.227 162 1650 07/28/15 07:16 37th Alley Out #1 Indv Btl. 0.176 0.094 0.131 5 250 07/28/15 08:00 37th Alley Out #3 Indv Btl. 0.184 0.149 0.160 4 280 07/28/15 08:44 37th Alley Out #5 Indv Btl. 0.276 0.169 0.192 11 320 07/28/15 09:28 37th Alley Out #7 Indv Btl. 0.498 0.420 0.368 5 320 07/28/15 10:12 37th Alley Out #9 Indv Btl. 0.498 0.420 0.379 8 300 07/28/15 10:56 37th Alley Out #11 Indv Btl. 0.480 0.402 0.373 5 260 07/28/15 11:40 37th Alley Out #13 Indv Btl. 0.479 0.455 0.368 4 270 37th & Alley Out GEO MEAN 0.339 0.258 0.258 6 285 37th & Alley Out MEDIAN 0.479 0.402 0.368 5 280 08/06/15 15:12 37th Alley In Composite 0.672 0.212 0.283 118 2000 08/06/15 16:12 37th Alley Out Composite 0.388 0.278 0.272 7 190 Non-precipitation event 08/09/15 14:21 37th Alley In Composite 0.335 0.144 0.163 26 570 08/09/15 15:03 37th Alley Out Composite 0.404 0.323 0.312 6 120 08/18/15 14:35 37th Alley In Composite 0.203 0.113 0.127 19 370 08/18/15 19:51 37th Alley Out Composite 0.340 0.293 0.283 2 140

Initially, the 37th & Morgan iron enhanced sand filter appeared to be removing TP, TSS, and dissolved phosphorus (TDP and Ortho-P) during the first three storms collected in June. However, after July 12th the IESF exported TDP and Ortho-P. This suggests that the dissolved phosphorus export is possibly soil temperature dependent and may be biologically driven, Figure 24-7. Also, 37th and Morgan site continually exported Fe throughout the study period. This site has a large deciduous shade tree on the southeast corner of the IESF that

2015 Water Resources Report – Minneapolis Park & Recreation Board Page 24-13 shades the IESF much of the day, Figure 24-1. Shading may prevent the 37th and Morgan IESF from drying out completely, creating wet anaerobic conditions, which may contribute to the export of Fe via iron reducing bacteria.

Similar to the 37th and Morgan site, the 37th Alley site appears to rremove TP and TSS early in the season, but after June 20th it also exported TDP and Ortho-P. While only one 37th Alley early season storm was collected, this site appears to follow same pattern as the 37th and Morgan IESF of late season dissolved phosphorus export. Nutrient export at this site may be soil temperature dependent and biologically driven. However, this site did not export Fe. The 37th Alley site is not shaded and has full sun most of the day, Figure 24-1. Drier conditions that do not favor the presence of iron reducing bacteria may explain why this IESF does not export Fe.

Since the IESFs are exporting dissolved phosphorus after mid-summer, the nuttrient export phenomenon is possibly tied to temperature and/or a biological process that transforms TP into dissolved phosphorus within the IESFs. Both IESFs removed TP from stormwater. This TP could then be digested by biological soil organisms, transforming the TP into TDP and Ortho-P. The nutrient export finding couldd also be due to the biological transformation of TP within the composts , placed during construction, in the iron enhanced sand filters, Figure 24-7.

Figure 24-7. Diagram of IESF increasing and decreasing conccentrations and possible paths for them. Question marks represent transformation of TP via biological activity. The blue arrows represent an increase or decrease in phosphorus.

2015 Water Resources Report – Minneapolis Park & Recreation Board Page 24-14

Figure 24-8 shows the orange color of the 37th & Morgan outlet sample bottles. The orange staining is from iron leaving the filter. From the top of the picture moving counterclockwise, the bottles get progressively darker as the filter exports iron through the storm.

Figure 24-8. The 37th and Morgan outlet samples. Starting at 1 o’clock and moving counter clockwise samples progress through the storm.

2015 Water Resources Report – Minneapolis Park & Recreation Board Page 24-15

Figures 24-9 through 24-13 show the events with individual inlet and outlet bottles sampled throughout the storm at 37th & Morgan. The graphs show the Ortho-P In/Out and the Fe In/Out, on the same time scale. This site received street runoff which was very high in organics from its residential watershed.

Figure 24-9. The 37th & Morgan IESF In/Out concentration of individual bottles during the 7/13/15 storm of 1.65”.

Figure 24-10. The 37th & Morgan IESF In/Out concentration of individual bottles during the 7/28/15 storm of 0.21”.

2015 Water Resources Report – Minneapolis Park & Recreation Board Page 24-16

Figure 24-11. The 37th & Morgan IESF In/Out concentration of individual bottles during the 9/117/15 storm of 0.21”.

Figure 24-12. The 37th & Morgan IESF In/Out concentration of individual bottles during the 9/24/15 storm of 0.10”.

2015 Water Resources Report – Minneapolis Park & Recreation Board Page 24-17

Figure 24-13. The 37th & Morgan IESF In/Out concentration of individual bottles during the 10/28/15 storm of 0.57”.

The 37th & Morgan site is exporting iron and dissolved phosphorus much of the time. Dissolved phosphorus export may be a product of two things. First, the TSS (organic solids load) coming from the street may be decomposing, becoming anaerobic and causing particulate total phosphorus too be converted into dissolved phosphorus, leading to the increase in dissolved phosphorus leaving the filter. Second, it is also possible that there is an unknown interaction with compost that was added to the sand filter that is releassing phosphorus that exists within the filter due to its construction. It should be noted that phosphorus remains iron bound only during aerobic conditions. If iron bound phosphorus becomes anaaerobic, the bond releases and phosphorus becomes mobile.

Iron is also being exported from the IESF at 37th and Morgan. The pH data in Table 24-2 show that the mobility of iron does not appear to be driven by low pH. Finally, the filter at 37th and Morgan is shaded and may not be drying out completely between storms. If it is remaining saturated,, anaerobic condition may be leading to iron mobilization. Under anaerobic conditions, iron reducing bacteria could convert solid Fe+3 to the more soluble Fe+2 state. The exact cause of iron release is unknown and was not able to be determined by this study.

2015 Water Resources Report – Minneapolis Park & Recreation Board Page 24-18 Figures 24-14 and 24-15 show the 37th Alley Ortho-P In/Out and the Fe In/Out. This site received alley runoff.

Figure 24-14. The 37th Alley IESF In/Out concentration of individual boottles during the 7/12/15 storm of 1.65”.

Figure 24-15. The 37th Alley IESF In/Out concentration of individual boottles during the 7/28/15 storm of 0.21”.

2015 Water Resources Report – Minneapolis Park & Recreation Board Page 24-19

The 37th Alley site appears to be removing TP, TSS, and Fe, but exporting dissolved phosphorus. The dissolved phosphorus export has two possible explanations. First, particulate phosphorus like organic solids could be breaking down, and transforming into dissolved phosphorus. Second, phosphorus export could be due to dissolved phosphorus leaching out of the IESF itself from phosphorus laden material within the BMP, like compost.

2015 Water Resources Report – Minneapolis Park & Recreation Board Page 24-20 Storm Event Statistics

Tables 24-4 and 24-5 show a statistical comparison of the inlet and outlet data for 37th & Morgan and 37th Alley sites.

Table 24-4. 37th & Morgan In/Out statistical comparison. The bold values, from the Indv Btl. Storm events, are the geometric mean of all of the bottles collected for that storm.

Date Site Sample TP TDP Ortho-P TSS Fe Sampled/Time Location Type mg/L mg/L mg/L mg/L ug/L 06/11/15 08:24 37th & Morgan In Composite 0.956 0.575 0.553 13 1000 06/20/15 07:04 37th & Morgan In Composite 0.872 0.273 0.341 130 2300 06/26/15 17:45 37th & Morgan In Composite 0.965 0.186 0.542 119 4800 07/13/15 02:12 37th & Morgan In Indv Btl. 0.346 0.029 0.064 54 862 07/18/15 04:49 37th & Morgan In Composite 0.199 0.107 0.106 15 230 07/28/15 10:05 37th & Morgan In Indv Btl. 0.213 0.104 0.110 15 334 08/07/15 01:16 37th & Morgan In Composite 0.433 0.077 0.119 55 490 08/09/15 14:42 37th & Morgan In Composite 0.425 0.187 0.187 17 530 08/18/15 21:34 37th & Morgan In Composite 0.132 0.061 0.068 9 140 09/10/15 05:29 37th & Morgan In Composite 0.120 0.098 0.070 11 200 09/17/15 07:12 37th & Morgan In Indv Btl. 0.234 0.136 0.125 39 239 09/24/15 07:09 37th & Morgan In Indv Btl. 0.259 0.193 0.121 12 312 10/28/15 05:30 37th & Morgan In Indv Btl. 1.13 0.962 0.850 13 32 MEAN (geometric) 0.369 0.151 0.171 25 420 MEAN (artithmatic) 0.483 0.230 0.251 39 882 MAX 1.13 0.962 0.850 130 4800 MIN 0.120 0.029 0.064 9 32 MEDIAN 0.346 0.136 0.121 15 334 STDEV 0.347 0.250 0.239 40 1267 NUMBER 13 13 13 13 13 COV 0.719 1.09 0.952 1 1

Date Site Sample TP TDP Ortho-P TSS Fe Sampled/Time Location Type mg/L mg/L mg/L mg/L ug/L 06/11/15 13:36 37th & Morgan Out Composite 0.364 0.222 0.243 52 3700 06/20/15 13:27 37th & Morgan Out Composite 0.262 0.121 0.118 8 2300 06/26/15 23:15 37th & Morgan Out Composite 0.286 0.044 0.115 18 8300 07/13/15 06:12 37th & Morgan Out Indv Btl. 0.223 0.163 0.208 2 1456 07/18/15 02:52 37th & Morgan Out Composite 0.322 0.146 0.244 11 4600 07/28/15 10:56 37th & Morgan Out Indv Btl. 0.296 0.243 0.260 2 683 08/07/15 09:21 37th & Morgan Out Composite 0.269 0.127 0.175 9 2500 08/10/15 08:36 37th & Morgan Out Composite 0.395 0.248 0.285 11 4900 08/19/15 04:30 37th & Morgan Out Composite 0.203 0.147 0.169 2 980 09/10/15 08:22 37th & Morgan Out Indv Btl. 0.209 0.140 0.189 5 2000 09/17/15 10:02 37th & Morgan Out Indv Btl. 0.229 0.154 0.187 2 1429 09/24/15 08:23 37th & Morgan Out Indv Btl. 0.239 0.184 0.182 4 1014 10/28/15 10:55 37th & Morgan Out Indv Btl. 0.903 0.823 0.797 6 890 MEAN (geometric) 0.295 0.171 0.213 6 2031 MEAN (artithmatic) 0.323 0.212 0.244 10 2673 MAX 0.903 0.823 0.797 52 8300 MIN 0.203 0.044 0.115 2 683 MEDIAN 0.269 0.154 0.189 6 2000 STDEV 0.177 0.184 0.167 13 2109 NUMBER 13 13 13 13 13 COV 0.546 0.865 0.684 1 1

2015 Water Resources Report – Minneapolis Park & Recreation Board Page 24-21 When comparing the 37th and Morgan geometric mean inlet and outlet concentrations of all of the storms combined Table 24-4, these data show the IESF filter is capturing a small amount of TP and TSS but is exporting dissolved phosphorus and iron. For example, the geometric mean TP was reduced from an inlet concentration of 0.369 mg/L to an outlet concentration of 0.295 mg/L. The 37th and Morgan IESF reduced TSS inlet geometric mean from an inlet concentration of 25 mg/L to an outlet concentration of 6 mg/L.

The 37th and Morgan IESF filter also exported dissolved phosphorus. For example the TDP geometric mean concentrations rose from an inlet value of 0.151 mg/L to an outlet value of 0.171 mg/L, and a geometric mean inlet Ortho-P concentration of 0.171 mg/L to an outlet concentration of 0.213 mg/L.

The Morgan IESF filter also saw a significant amount of iron being exported, going from an inlet geometric mean concentration of 0.420 mg/L to an outlet concentration of 2.031 mg/L.

Table 24-5. 37th Alley In/Out statistical comparison. The bold values, from the Indv Btl. Storm events, are the geometric mean of all of the bottles collected for that storm.

Date Site Sample TP TDP Ortho-P TSS Fe Sampled/Time Location Type mg/L mg/L mg/L mg/L ug/L 06/20/15 06:00 37th Alley In Composite 1.40 0.500 0.536 162 3100 06/22/15 08:41 37th Alley In Composite 0.396 0.113 0.153 45 1100 07/06/15 00:41 37th Alley In Composite 0.387 0.139 0.226 230 430 07/13/15 00:20 37th Alley In Indv Btl. 0.388 0.105 0.188 145 2014 07/28/15 07:00 37th Alley In Indv Btl. 0.418 0.186 0.247 145 1750 08/06/15 15:12 37th Alley In Composite 0.672 0.212 0.283 118 2000 08/09/15 14:21 37th Alley In Composite 0.335 0.144 0.163 26 570 08/18/15 14:35 37th Alley In Composite 0.203 0.113 0.127 19 370 MEAN (geometric) 0.447 0.164 0.218 82 1102 MEAN (artithmatic) 0.524 0.189 0.240 111 1417 MAX 1.40 0.500 0.536 230 3100 MIN 0.203 0.105 0.127 19 370 MEDIAN 0.392 0.142 0.207 131 1425 STDEV 0.351 0.123 0.122 70 903 NUMBER 8 8 8 8 8 COV 0.670 0.649 0.507 0.629 0.638

Date Site Sample TP TDP Ortho-P TSS Fe Sampled/Time Location Type mg/L mg/L mg/L mg/L ug/L 06/20/15 07:27 37th Alley Out Composite 0.332 0.277 0.269 2 160 06/22/15 10:01 37th Alley Out Composite 0.341 0.309 0.278 7 98 07/06/15 09:22 37th Alley Out Composite 0.214 0.160 0.154 10 250 07/13/15 01:11 37th Alley Out Indv Btl. 0.145 0.101 0.107 3 265 07/28/15 11:40 37th Alley Out Indv Btl. 0.339 0.258 0.258 6 285 08/06/15 16:12 37th Alley Out Composite 0.388 0.278 0.272 7 190 08/09/15 15:03 37th Alley Out Composite 0.404 0.323 0.312 6 120 08/18/15 19:51 37th Alley Out Composite 0.340 0.293 0.283 2 140 MEAN (geometric) 0.299 0.235 0.229 5 177 MEAN (artithmatic) 0.313 0.250 0.242 5 188 MAX 0.404 0.323 0.312 10 285 MIN 0.145 0.101 0.107 2 98 MEDIAN 0.339 0.278 0.271 6 175 STDEV 0.083 0.073 0.067 3 66 NUMBER 8 8 8 8 8 COV 0.264 0.292 0.276 0.493 0.351

2015 Water Resources Report – Minneapolis Park & Recreation Board Page 24-22 When comparing the 37th Alley geometric mean inlet and outlet concentrations Table 24-5, these data show the Alley IESF filter is capturing a small amount of TP and also capturing TSS. The TP went from an inlet geometric mean concentration of 0.447 mg/L to an outlet geometric mean concentration of 0.299 mg/L. The 37th Alley TSS went from an inlet geometric mean of 82 mg/L to an outlet geometric mean of 5 mg/L. The 37th Alley site captured iron with an inlet geometric mean of 1102 µg/L and an outlet geometric mean of 5 µg/L.

In conclusion, both the Street and Alley runoff IESFs are exporting more dissolved phosphorus than they are receiving. The dissolved phosphorus is either being biologically transformed from the inlet TP organic load into dissolved phosphorus or the compost added to the IESF during construction could be an internal source of phosphorus.

The 37th and Morgan IESF is exporting iron. The exact mechanism is unknown but it is proposed that tree shading at this site is preventing the IESF from drying out and causing anaerobic saturated soil conditions leading to the possible mobilization of iron by iron reducing bacteria. Future pH, alkalinity and hardness data should be collected to determine if the iron loss is due to pH or a lack of buffering capacity in the IESF, which also could mobilize iron.

The landscape woodchips which are used to retain moisture for the plants in the IESF may be retaining moisture and preventing IESFs from drying out. Prolonged wet conditions within the IESFs could lead to conditions favoring phosphorus and iron export, either though chemical or biological transformation. It is recommended that woodchips covering the 37th St Greenway basins be removed in order to begin to test the hypothesis that prolonged wet conditions could be favoring TDP and Fe export from the site.

Barr Engineering, the project designer, will be consulted for any future experimental design changes to help better understand why both IESF’s are exporting dissolved phosphorus and the 37th and Morgan IESF is exporting iron.

Areas of possible future study for the 37th Avenue Greenway IESFs are:  Remove wood chips to determine if this organic layer prevents drying.  Consider removing compost to test if this material is a phosphorus source.  Use soil moisture sensor to determine how long it takes for the IESF to dry out.

When siting additional IESFs it is recommended that:  Future IESFs be constructed in sunny areas to facilitate return to dry, aerobic conditions.  Pretreatment at future IESFs removes sediment and organic matter, as excess sediment and organic matter could lead to anaerobic conditions in the IESF.  Carefully consider whether compost is needed, as it may be a phosphorus source.

2015 Water Resources Report – Minneapolis Park & Recreation Board Page 24-23 th 25. 37 & Oliver Flood Relief Vault

BACKGROUND

The 37th Greenway underground vault project was built for flood relief in 2011, Figure 25-1. An underground flood retention vault at 37th and Olivere Avenue North was monitored in 2015 to determine if the vault provided any reduction in water depth (stage) in the downstream 24” reinforced concrete pipe (RCP). This is one of the flood vaults installed in the 37th greenway project. The vault waas built to atttenuate peak flow in the downstream 24” RCP pipe.

The project drainage area is 5.5 acres, 50% impervious, and residential with a dense tree canopy.

Installation of monitoring equipment for this project occurred on 4/28/15. On 5/13/15, to better achieve laminar flow in the 24” outlet pipe, the area velocity (AV) probbe was moved further downstream in the pipe.

Outlet 24” RCP

AV Probes located 37th Ave N. Oliver Ave N. 37th Underground Reelief Vault

Figure 25-1. Map of 37th and Oliver stormsewer pipe structure and storage vault.

METHODS

Equipment Used and Installation The monitoring equipment installed at the 37th and Oliver vault was a 2105ci cell phone modem, two 2150 dataloggers, two battery modules, and two area velocity probes. An extra-lonng AV probe cable was needed for the 24” downstream pipe and a standard AV probe was used to measure the level in the vault. The equipment was hung from a side-iron in the manhole.

Help from cement masons was critical to the project due to the large number of eye-bolts and anchors were needed for both AV probes and associated cables. Figure 25-2 shows the leveel probe being anchored to the vault floor. Figure 25-3 shows the outlet to the vault leading to the 24” downstream pipe. The 24” downstream pipe required a spring ring, because it was installed 4-5 feet into the downstream pipe where it is

2015 Water Resources Report – Minneapolis Park & Recreation Board Page 25-1 not possible to use power tools. Figures 25-4 and 25-5 show the 24” downstream pipe installation and final spring ring configuration. A cell phone antenna was buried in the sidewalk foor better reception.

Both dataloggers at the site were programed to push up data to a server database via the cell phone modeem, Monday through Friday.

Figure 25-2. AV Anchor plate being installed in the vault floor.

Vault Inlet/ Outtlet

24” RCP Downstream Outlet

Figure 25-3. Photograph showing the vault entrance/exit pipe (right) and 24” downstream stormsewer outlet (left).

2015 Water Resources Report – Minneapolis Park & Recreation Board Page 25-2

Figure 25-4. Installation of the spring ring in the 24” downsttream outlet pipe.

Springn Ring

AV Probe

Figure 25-5. The spring ring and AV probe installed in the 24” downstream pipe.

2015 Water Resources Report – Minneapolis Park & Recreation Board Page 25-3 RESULTS & DISCUSSION

Level and Stage Data Figure 25-6 shows the stage in both the vault and the 24” RCP sttormsewer piipe from May through November 2015.

7/6/15 2.53” Storrm

Figure 25-6. Graph of the stage in both the pipe and vault. The pipe level is pink and the vault level is black.

Figure 25-6 shows the effects of the level in the pipe in pink, and the level of the vault in black. The vault appeared to provide a maximum amount of approximately two inches of stage reduction in the downstream pipe compared to the level in the vault during the largest storm of 2015. The flood relief in the pipe appears minimal but may have a significant effect on larger storms or stoorms not experrienced in 2015.

In conclusion, the vault appears to be working to attenuate the peak discharge in the downstream 24” RCP. The stage in the underground vault varied when compared to the 24” downstream pipe but the vault relieved a maximum of approximately two inches of stage in the downstreaam pipe, as shown in Figure 25-6. The stage in the vault never exceeded 15.24” during the largest storm on 7/6/15 of 2.53”. The 24” RCP downstream pipe did not surcharge in 2015.

2015 Water Resources Report – Minneapolis Park & Recreation Board Page 25-4 26. Webber Stormwater Pond (WSP)

BACKGROUND

The Webber Stormwater Pond (WSP) construction began in 2013 and finished in 2015. The purpose of this study is to determine how well the WSP treats runoff from the adjacent Webber Natural Swimming Pool (WNSP) and surrounding area. The stormwater pond is the only remaining remnant of the old Webber Pond (former public water 27111800). It has two inlets and one outlet, Figure 26-1 and 26-2. The North Inlet is a 12 inch reinforced concrete pipe (RCP) and takes drainage from the WNSP overflow and immediate pool area. The South Inlet is a 24 inch RCP and takes drainage from the WNSP wash basin and a few catch basins surrounding the WNSP, Figure 26-3. An underdrain, beneath the WNSP, is another potential water source to the pond, and may be a source of groundwater to the WSP.

The WSP outlet is a vault with an orifice and a weir. The orifice is a 4 inch hole about a 1 foot below the top of the weir. Most of the drainage flows through the orifice into a 12 inch pipe, but during large storms water overtops the weir. The Webber Stormwater Pond (WSP) discharges to Shingle Creek, Figure 26-4.

N. Inlet

S. Inlet

Outlet

Figure 26-1. Aerial photo of Webber stormwater pond during construction.

2015 Water Resources Report – Minneapolis Park & Recreation Board Page 26-1

Inlets

Outlet Weir

Figure 26-2. Photo of Webber stormwater pond following construction.

Figure 26-3. Webber South inlet 24 inch RCP pipe. Arrow shows direction of flow.

Figure 26-4. Webber outlet 12 inch RCP pipe. Arrow shows direction of flow towards Shingle Creek.

2015 Water Resources Report – Minneapolis Park & Recreation Board Page 26-2

The drainage area of the South Inlet (24” RCP) is 85,000 square feet and the North Inlet (12” RCP) drainage area is 43,000 square feet. The land use is the pool patio and grassed area around the WNSP as well as pool water discharged to the North Inlet from the WNSP.

METHODS

Site Installation Due to its proximity and secure location, a tipping bucket rain gauge was installed on the roof of Folwell Recreation Center where precipitation data was also collected for an iron enhanced sand filter BMP project. Folwell Park is three quarters of a mile of Webber Pond. Data was periodically collected throughout the summer from a Hobo datalogger attached to the rain gauge. When precipitation data were missing, data was supplemented with information from the 38th and Bryant Ave S. MPRB South Side Service Center.

In 2015, there were delays in installation due delays in construction at the NSP and stormwater pond. The South Inlet monitoring equipment was installed on 7/10/15, the North Inlet monitoring equipment was installed on 7/9/15, and the Outlet monitoring equipment was installed on 6/24/15. Monitoring equipment at each of the sites included an ISCO 2150 datalogger, 2105 interface module, 2103ci cell phone modem, a low-profile A/V (area velocity) level probe, and a 3700 ISCO sampler. The inlets were too shallow to hang equipment and required above ground doghouse monitoring boxes. The datalogger used the cell phone modem to remotely upload data to a server daily Monday through Friday. The datalogger could also be remotely called up and programmed to change the pacing or triggers.

The samplers were flow-paced and equipped with 24 one liter bottles, 3/8” ID (inner diameter) vinyl tubing, and an intake strainer. The sampler was programmed to multiplex, taking four flow-paced samples per bottle, allowing for 96 flow-paced samples per storm.

Sample Collection The South Inlet was set to trigger at 0.75 inches of flow to avoid the non-precipitation events and paced at 65 cubic feet. The North Inlet was initially set to trigger at 0.75 inches of flow but later adjusted up to 1.25 inches to avoid the non-precipitation events and paced at 50 cubic feet. Non-precipitation events produced enough flow to trigger the inlets but not the pond outlet. The outlet appeared to have an almost continuous baseflow of less than 1 inch for much of the summer. The outlet trigger was set for 1 inch.

RESULTS & DISCUSSION

Sample Collection In 2015, six Webber North Inlet and nine Webber South Inlet storms were collected. At the Webber Outlet, ten storms were collected (Table 26-1).

The South Inlet had a significant number of non-precipitation events due to a wash pad located in its watershed being used one to three times a day to clean filter bags. The filter bag washings became less frequent at the end of summer with the purchase of a new robot to clean the WNSP. The non-precipitation events experienced at the North Inlet occurred due to irrigation water overspray and pool discharge. It was a significant challenge to collect stormwater events and separate out non-stormwater events created from daily maintenance and irrigation discharge.

2015 Water Resources Report – Minneapolis Park & Recreation Board Page 26-3

Verizon cell phone service is very weak in this area of Minneapolis. All of the dataloggers suffered weak signals and communication issues. The North inlet datalogger had several modem communication and internal software problems that required substantial time to solve with the manufacturer. These issues did not lead to loss of data.

Table 26-1. The 2015 precipitation events captured near Webber Stormwater Pond. The rain gauge was on the roof of the Folwell Recreation Center. A precipitation event was defined as a storm greater than 0.10 inches, separated by eight hours or more from other precipitation.

Time since Precip Duration last Precip. Intensity Webber Webber Webber Start Date/Time End Date/Time (inches) (hours) (hours) inch/hr Inlet North Inlet South Outlet 7/6/2015 0:52 7/6/2015 13:11 0.34 12 683 0.03 X(bact. only) 07/12/2015 23:30 7/13/2015 10:00 1.65* 10.5 155 0.16 XX 07/15/2015 7:00 7/15/2015 17:00 0.13* 10 45 0.01 XX 7/18/2015 0:53 7/18/2015 10:53 0.11 10 276 0.01 X(lmtd) X(lmtd) X 7/28/2015 6:18 7/28/2015 11:05 0.21 5 92 0.04 XXX 8/6/2015 9:48 8/7/2015 9:20 0.23 24 215 0.01 X(lmtd) X X 8/18/2015 11:10 8/19/2015 10:12 0.35 23 266 0.02 X(lmtd) X Non Precip Event 8/27/2015 0:00 X(bact. only) X(bact. only) Non Precip Event 9/8/2015 0:00 X(bact. only) 9/9/2015 12:16 9/10/2015 6:39 0.13 18 68 0.007 XXX(lmtd) 9/17/2015 4:59 9/17/2015 22:17 0.21 17 166 0.01 X(W/bact.) X(W/bact.) X(W/bact.) *SSSC precip data

X = event sampled with full parameters X(lmtd) = event sampled with limited parameters generally due to holding times e.g.BOD, Ortho P, and TDP X(w/bact.) = event sampled for bacteria X(bact. only) = only bacteria sampled

Figures 26-5 through 26-7 show the stage discharge of the two Webber inlets (North and South) and the outlet for 2015. During the period of record, the South Inlet had 59,828 cf measured, the North Inlet had 87,602 cf measured, and the Outlet had 260,280 cf measured. These figures are not the same time period, but the period of record that each were monitored.

The additional outlet volume, in the mass balance, was caused by a number of contributing factors. First, the two inlets were very shallow so the temperature was not stable and caused drift in both inlet probes which slightly affected the amount of discharge calculated by the probes. Second, an underdrain beneath the WNSP may carry groundwater to the pond that is not measured by the inlets. Although the WSP is lined, the outlet had a consistent baseflow which supports the hypothesis that groundwater is discharging into the WSP. Finally, when comparing the period of record, the sites were installed at slightly different times. The Outlet site was installed two weeks prior to the Inlet installation and so consequently the outlet probe measured more water.

Figures 26-5 and 26-6 (Inlets) show the level and discharge for the period of record. Diurnal swings in temperature, automatic irrigation overspray (at 1am and 4am), and WNSP discharge at the north inlet created 2015 Water Resources Report – Minneapolis Park & Recreation Board Page 26-4

“noise” in the charts. The Outlet site presented in Figure 26-7 shows the level and discharge for the period of record. A 1.65 inch storm on July 13 was the only storm that caused the outlet weir to be overtopped.

Loads were calculated using the same time periods, 7/25/15 through 11/5/15, and can be seen in Table 26-4. The mass balance of inlets vs outlet during the same time period (7/25/15 – 11/5/15) shows that the outlet is measuring ~38% more water than the inlets. This discrepancy may be due to groundwater discharging from the underdrain tile or a breach in the pond liner allowing in groundwater.

Figure 26-5. Webber Inlet South stage and discharge for the period of record.

2015 Water Resources Report – Minneapolis Park & Recreation Board Page 26-5

Figure 26-6. Webber Inlet North stage and discharge for the period of record.

Figure 26-7. Webber Outlet stage and discharge for the period of record. 2015 Water Resources Report – Minneapolis Park & Recreation Board Page 26-6

Storm Event Data and Statistics

Table 26-2 shows the 2015 Webber Stormwater Pond water chemistry data. Due to site construction, installation was delayed until mid-summer. Some of the events collected were analyzed for limited parameters because of low volume or expired holding times. The pond appears to reduce many chemical parameters (TP, TDP, Ortho-P, TKN, NH3, NO3NO2, TSS, VSS, cBOD, and all metals) as they settled out or were degraded. The bacterial data are limited and vary widely. From the outlet data, it appears that the pond does settle out or degrade bacteria.

Data that are underlined in Table 26-2 failed the blind monthly MPRB internal QAQC performance standard for that parameter for that month. It was deemed the data can be used, with the caution, noting that performance standards were outside the 80% to 120% recovery standards.

2015 Water Resources Report – Minneapolis Park & Recreation Board Page 26-7

Table 26-2. Webber Stormwater Pond water chemistry events data. Cells with “less than” values indicate that the concentration of that parameter was below detection limit. NA = data not available due to expired holding time or low volume. Data that are underlined had a blind performance standard failure for that month, for that parameter. Date Sampled Time Site Location Sample TP TDP Ortho-P TKN NH3 NO3NO2 Cl Hardness TSS VSS TDS cBOD Sulfate Sp.Cond. pH E. Coli Enterococi Pseduomonas Cu Pb Zn Type mg/L mg/L mg/L mg/L mg/L mg/L mg/L mg/L mg/L mg/L mg/L mg/L mg/L uhmos std units MPN MPN MPN ug/L ug/L ug/L 7/13/2015 0:29 Webber In South composite 0.524 0.084 0.108 2.75 <0.500 <0.030 14 58 36 28 120 5 <5.0 230 7.1 <5.00 7 34 7/15/2015 7:03 Webber In South composite 0.170 0.025 0.046 1.64 <0.500 0.592 25 80 54 18 191 <1.00 19.4 358 7.2 <5.00 6 <20.0 7/18/2015 4:13 Webber In South composite 0.370 NA NA 1.22 NA 0.365 14 44 92 27 229 NA NA NA NA <5.00 10 27 7/28/2015 7:03 Webber In South composite 1.46 0.173 0.227 9.38 <0.500 0.203 7 30 547 204 88 32 8.3 235 6.8 44 27 160 8/7/2015 2:48 Webber In South composite 0.803 0.061 0.252 7.24 2.85 0.712 13 76 174 37 136 21 23.5 328 7.5 49 11 94 8/19/2015 17:27 Webber In South composite 0.418 0.078 0.080 3.48 1.37 0.401 17 76 111 53 144 8 22.3 264 7.2 <5.00 4.6 47 8/27/2015 10:05 Webber In South grab 12033 185 9/9/2015 21:11 Webber In South composite 1.10 0.339 0.258 13.9 4.45 0.120 3 104 655 244 113 NA 5.82 305 NA NA NA NA 9/17/2015 14:52 Webber In South composite 0.314 0.192 0.208 2.25 0.853 0.375 15 76 82 24 144 6 19.5 259 7.3 31 4 41 9/17/2015 11:16 Webber In South grab 10460 104620 7/18/2015 2:37 Webber In North composite 0.293 NA NA 1.12 NA 0.176 <2.0 56 77 21 105 NA NA NA NA <5.00 9 28 7/28/2015 7:14 Webber In North composite 0.570 0.253 0.265 2.11 <0.500 0.078 3 20 155 40 66 7 10.3 111 6.8 <5.00 19 49 8/7/2015 1:09 Webber In North composite 0.722 0.107 0.226 2.58 <0.500 0.225 8 72 122 40 119 NA NA 194 NA NANANA 8/19/2015 1:49 Webber In North composite 0.180 NA 0.092 1.28 <0.500 <0.030 16 72 NA NA NA NA NA NA NA NANANA 9/10/2015 1:47 Webber In North composite 0.197 0.082 0.106 1.49 0.686 9.04 26 100 55 19 145 NA 26.2 279 NA NA NA NA 9/17/2015 12:22 Webber In North composite 0.904 0.143 0.271 7.38 1.00 0.092 13 96 669 174 186 NA 17.5 253 7.1 <5.00 4 <20.0 9/17/2015 11:15 Webber In North grab >242000 120330 7/6/2015 14:30 Webber Outlet grab 1300 7/14/2015 9:39 Webber Outlet composite 0.097 0.038 0.029 1.09 <0.500 0.344 15 112 13 2 191 <1.00 52.0 339 7.5 <5.00 <3.00 <20.0 7/15/2015 8:30 Webber Outlet composite 0.068 0.042 0.024 1.05 <0.500 0.031 14 110 6 <2.0 155 <1.00 51.7 329 7.6 <5.00 <3.00 <20.0 7/19/2015 2:08 Webber Outlet composite 0.076 NA NA 0.537 NA 0.029 15 100 12 6 314 NA NA NA NA <5.00 <3.00 <20.0 7/29/2015 2:08 Webber Outlet composite 0.107 0.076 0.057 0.831 <0.500 <0.030 15 38 6 5 131 3 32.3 235 7.9 <5.00 <3.00 <20.0 8/7/2015 4:57 Webber Outlet composite 0.102 0.097 0.072 0.766 <0.500 <0.030 17 76 3 <2.0 147 29.7 254 9.1 <5.00 <3.00 <20.0 8/19/2015 1:19 Webber Outlet composite 0.077 0.060 0.047 0.788 <0.500 <0.030 18 76 2 <2.0 157 4 26.4 231 8.6 <5.00 3 <20.0 8/27/2015 9:50 Webber Outlet grab 84 411 9/8/2015 10:15 Webber Outlet grab 77 15 9/9/2015 22:25 Webber Outlet composite 0.106 NA 0.069 1.04 0.621 NA 18 80 NA NA NA NA NA NA NA 9/17/2015 11:20 Webber Outlet grab >242000 >242000 9/18/2015 2:14 Webber Outlet composite 0.129 0.089 0.075 0.989 0.664 0.083 17 80 8 4 186 6 23.1 262 7.1 41 <3.00 <20.0 9/16/2015 14:15 Webber Outlet - non event grab >2420 1553

2015 Water Resources Report – Minneapolis Park & Recreation Board Page 26-8

Table 26-3 shows statistics from the Webber Pond Inlets and Outlet. Statistics were only calculated for a chemical parameter if there were two or more measured values. When statistical analysis was performed on the data sets, and less than values were present, half of the less than value was used in the calculations.

In comparing the geometric means of inlets vs outlet, it appears that the stormwater pond is removing much of the (TP, TDP, Ortho-P, TKN, NH3, NO3NO2, TSS, VSS, cBOD, and all metals) either by settling or degradation. The Outlet samples had higher concentrations of Cl, Hardness, TDS, and Sulfate, when compared to the Inlets. The increase in concentration of these chemical parameters at the outlet may be due to soil erosion in the pond basin, nutrient contributions from waterfowl, or a connection with groundwater.

2015 Water Resources Report – Minneapolis Park & Recreation Board Page 26-9

Table 26-3. Webber Stormwater Pond 2015 data showing statistics of the inlets and outlet. All “less than data” were transformed into half the reporting limit for statistical calculations (e.g. Pb <3 becomes 1.5). NA = data not available due to limited samples.

Site Statistical TP TDP Ortho-P TKN NH3 NO3NO2 Cl Hardness TSS VSS TDS cBOD Sulfate Cu Pb Zn ID Function mg/L mg/L mg/L mg/L mg/L mg/L mg/L mg/L mg/L mg/L mg/L mg/L mg/L ug/L ug/L ug/L Webber Inlet South MEAN (geometric) 0.523 0.102 0.143 3.77 0.811 0.343 12 64 133 49 140 6 11 8.25 7.74 42.9 Webber Inlet South MEAN (arithmetic) 0.645 0.136 0.168 5.23 1.47 0.395 14 68 219 79 146 12 14 19.1 9.69 59.0 Webber Inlet South MAX 1.46 0.339 0.258 13.9 4.45 0.712 25 104 655 244 229 32 23 49.0 27.0 160 Webber Inlet South MIN 0.170 0.025 0.046 1.22 0.250 0.120 3 30 36 18 88 1 3 2.50 3.50 10.0 Webber Inlet South MEDIAN 0.471 0.084 0.208 3.12 0.853 0.375 14 76 102 32 140 7 19 2.50 6.60 41.0 Webber Inlet South STDEV 0.443 0.108 0.088 4.53 1.61 0.205 7 23 241 90 45 12 9 21.4 8.09 51.5 Webber Inlet South NUMBER 8 7 787 78 888867777 Webber Inlet South COV 0.687 0.793 0.522 0.865 1.10 0.519 0.480 0.340 1.10 1.14 0.309 1.00 0.597 1.12 0.835 0.874 Webber Inlet North MEAN (geometric) 0.396 0.133 0.174 2.10 0.404 0.303 7 62 140 41 117 NA 17 2.50 8.49 23.9 Webber Inlet North MEAN (arithmetic) 0.478 0.146 0.192 2.66 0.487 1.92 11 69 216 59 124 NA 18 2.50 10.5 29.0 Webber Inlet North MAX 0.904 0.253 0.271 7.38 1.00 9.04 26 100 669 174 186 NA 26 2.50 19.0 49.0 Webber Inlet North MIN 0.180 0.082 0.092 1.12 0.250 0.078 1 20 55 19 66 NA 10 2.50 3.70 10.0 Webber Inlet North MEDIAN 0.432 0.125 0.226 1.80 0.250 0.176 10 72 122 40 119 NA 18 2.50 8.70 28.0 Webber Inlet North STDEV 0.300 0.075 0.087 2.38 0.343 3.98 9 29 256 65 45 NA 8 0.00 7.80 19.5 Webber Inlet North NUMBER 6 4 565 56 655513333 Webber Inlet North COV 0.629 0.516 0.452 0.894 0.705 2.07 0.836 0.422 1.19 1.11 0.360 NA 0.442 0 0.745 0.673 Webber Outlet MEAN (geometric) 0.093 0.063 0.049 0.865 0.327 0.037 16 80 6 2 176 2 34 3.73 1.66 10.0 Webber Outlet MEAN (arithmetic) 0.095 0.067 0.053 0.885 0.362 0.076 16 84 7 3 183 3 36 8.00 1.71 10.0 Webber Outlet MAX 0.129 0.097 0.075 1.09 0.664 0.344 18 112 13 6 314 6 52 41.0 3.00 10.0 Webber Outlet MIN 0.068 0.038 0.024 0.537 0.250 0.015 14 38 2 1 131 1 23 2.50 1.50 10.0 Webber Outlet MEDIAN 0.100 0.068 0.057 0.910 0.250 0.029 16 80 6 2 157 3 31 2.50 1.50 10.0 Webber Outlet STDEV 0.020 0.024 0.021 0.188 0.192 0.121 2 24 4 2 62 2 13 14.6 0.567 0 Webber Outlet NUMBER 8 6 787 78 877756777 Webber Outlet COV 0.213 0.364 0.388 0.213 0.530 1.59 0.110 0.284 0.588 0.742 0.336 0.830 0.356 1.82 0.331 0 NA = data not available

2015 Water Resources Report – Minneapolis Park & Recreation Board Page 26-10

Table 26-4 shows the load calculations (for the same period of time 7/25/15 through 11/5/15), when all of the equipment was installed and functional. The geometric mean of all of the data for a specific parameter was used for the load concentration calculation. Webber Stormwater Pond appears to be exporting more water, Chloride, Hardness, Total Dissolved Solids, and Sulfate than it received. The Pond is capturing Total Phosphorus, Nitrogen, Total Suspended Solids, Volatile Suspended Solids, and metals. The North Inlet cBOD could not be calculated due to the limited number of events.

Table 26-4. Load calculations comparing inlets and outlet, in pounds, to the Webber Stormwater Pond for the period 7/25/15 through 11/5/15. Yellow highlighted areas are where the parameter is exporting. LOADS Water TP TDP Ortho-P TKN NH3 NO3NO2 Cl Hardness TSS VSS TDS cBOD Sulfate Cu Pb Zn Dates 7/25 - 11/5 cubic ft Lbs Lbs Lbs Lbs Lbs Lbs Lbs Lbs Lbs Lbs Lbs Lbs Lbs Lbs Lbs Lbs Webber Inlet South 40,669 1.33 0.26 0.36 9.6 2.06 0.87 30 162 339 124 355 16 29 0.02 0.02 0.11 Webber Inlet North 87,602 2.17 0.73 0.95 11.5 2.21 1.66 38 338 765 223 642 NA 92 0.01 0.02 0.06 Webber Outlet 177,365 1.03 0.70 0.54 9.6 3.62 0.40 178 889 67 25 1949 20 378 0.01 0.004 0.03 Lbs Removed (Added) (49,094) 2.46 0.29 0.77 11.5 0.64 2.13 (111) (389) 1036 321 (951) NA (257) 0.02 0.04 0.14 % Reduction/Added -38% 70% 29% 59% 54% 15% 84% -166% -78% 94% 93% -95% NA -213% 65% 90% 85%

2015 Water Resources Report – Minneapolis Park & Recreation Board Page 26-11

The hydrological mass balance showing more water leaving the stormwater pond than entering was surprising. This finding is likely due to groundwater entering the pond from either the WNSP underdrain or a breach in the liner. The impact of the WNSP underdrain drain will need to be assessed to see what impact it could be having on the WSP.

The outlet does an excellent job of retaining stormwater and attenuates peak storm events. The pond and its outlet structure (weir with 4” orifice) make even small storm drainage last for days. However, this retention feature can be challenging when trying to cleanly separate (inlet outlet) paired storms when they comingle due to the long drawdown time of the pond.

The North Inlet is a 12 inch pipe and had more recorded flow than the South Inlet 24 inch pipe. A significant amount of irrigation overspray affected that site. The irrigation sprinklers were programed to automatically irrigate at 1am and 4am. MPRB staff will need to be notified of this overspray, its effects, and to try and mitigate this. The WNSP also drained through the North 12” Inlet which accounts for a significant amount of water discharged through this pipe.

Daily filter bag washing events affected the South 24” inlet pipe. Sampler triggers had to be set very high on the inlets which caused some low intensity storms to be missed. A new pool cleaning robot was purchased late summer 2015 which reduced the number of bag washings to once a day. Some of the non-precipitation inlet events were collected and analyzed but they do not produce enough flow to trigger the outlet sampler as currently programmed. In 2016 more of these non-precipitation events will be collected to better characterize them and to compare the non-precipitation events that the pond captures to stormwater.

In conclusion, the Webber Stormwater Pond reduces bacteria and most pollutants from the adjacent Natural Swimming Pool, but a few parameters saw an increase rather than a reduction in discharge. It is unknown where these pollutants are coming from, or if the pond needs a “break in” period where it will come to equilibrium.

2015 Water Resources Report – Minneapolis Park & Recreation Board Page 26-12

27. Lyndale Farmstead Dog Park

BACKGROUND

The Lyndale Farmstead Dog Park was built in 2012, Figure 27--1. It was a former parking lot used for equipment storage and overflow parking at the adjacent Minneapolis Park Board Service Center. It is approximately 0.56 acres in area and its surface is entirely crushed gravel thaat is sloped to the southwest side where an underdrain carries runoff to the adjacent stormwater pond. The dog park is located next to a stormwater pond that handles drainage from the adjacent resideential watershed.

Following construction, fine particles washed off the gravel and plugged the subsurface BMP drainage filter causing ponding. Ponding in the dog park caused muddy and unpleasant conditions for park patrons. In 2013, above ground surface drains were retrofitted directly to the subsurface underdrain. This retrofit prevented ponding, butu circumvented filtration.

The Lyndale Dog Park drains directly to the adjacent stormwater pond where it is pumped to the Mississippi via a stormwater lift station. The adjacent stormwater pond floods a few times a year which, depending on the amount of precipitation and storm intensity, sometimes results in flooding half or more of the dog park.

Kings Highway or DupontKings Highway Ave S

Sampling Point .

Stormwater Pond

Figure 27-1. Map of Lyndale Farmstead Dog Park and adjacent stormwater pond.

2015 Water Resources Report – Minneapolis Park & Recreation Board Page 27-1

METHODS

Sample Collection Bacteria grab samples were collected during precipitation events. Samples were obtained with a modified dip pole, Figure 27-2. The time, date and depth of flow in the pipe was recorded when the grab sample was collected.

Figure 27-2. Collecting bacteria grab sample at Lyndale Farmstead Dog Park.

It took several storms to determine which pipe was the dog park underdrain. Initially the visible 12” RCP pipe was incorrectly sampled. Later, the smaller PVC pipe (above the 12” RCP) was determined to be the correct underdrain pipe, and was sampled, Figure 27-3.

All precipitation events were measured via a tipping bucket rain gauge at the adjacent South Side Service Center, approximately 100 yards away.

2015 Water Resources Report – Minneapolis Park & Recreation Board Page 27-2

Figure 27-3. View inside the vault of Lyndale Farmstead Dog Park. The small PVC pipe at the top is the underdrain to the dog park.

RESULTS & DISCUSSION

Sample Collection Due to the large surface area of the gravel bed, it appears that at least ¼ inch of rain is needed to overcome depressional storage and produce runoff. If there is more than approximately 1 ½ inches of rain, and a sample is not collected immediately, the stormwater pond can surcharge the pipe, making sampling impossible.

Table 27-1 shows the precipitation events sampled in 2015.

2015 Water Resources Report – Minneapolis Park & Recreation Board Page 27-3

Table 27-1. The 2015 precipitation events captured at the Lyndale Dog Park. A precipitation event was defined as being separated by eight hours or more from other precipitation. Time since Start End Precip Duration Intensity last Precip. Lyndale Dog Date/Time Date/Time (inches) (hours) (in/hr) (hours) Park 5/26/2015 10:15 5/27/2015 12:30 1.19 26.25 0.05 25 X(w/bact.) 6/3/2015 8:15 6/3/2015 20:15 0.72 12.00 0.06 107 X(w/bact.) 6/22/2015 7:00 6/22/2015 16:15 1.52 9.25 0.16 47 X(bact./chem) 7/6/2015 0:30 7/6/2015 12:15 2.52 11.75 0.21 176 X(bact./chem) 8/18/2015 10:15 8/19/2015 12:30 0.87 26.25 0.03 15 X(w/bact.) 10/23/2015 5:00 10/24/2015 2:30 1.63 21.50 0.08 357 X(w/bact.) 11/16/2015 7:30 11/19/2015 12:15 1.66 79.25 0.02 98 X(w/bact.) X(w/bact.) = event sampled for bacteria X(bact./chem) = bacteria sampled with TP and TSS

Event Data Table 27-2 shows the 2015 chemistry and bacteria data collected at the Lyndale Dog Park. The dog park E. coli bacteria samples ranged from 3,076 MPN to greater than 24,200 MPN.

Table 27-2. The 2015 chemistry and bacteria data collected at the Lyndale Dog Park. Date Time Site Sample TP TSS E. coli Sampled Location Type mg/L mg/L MPN 5/26/2015 10:45 Dog Park Underdrain grab 19,863 6/3/2015 13:30 Dog Park Underdrain grab 12,033 6/22/2015 8:30 Dog Park Underdrain grab 0.518 216 >2,420 7/6/2015 8:10 Dog Park Underdrain grab 0.209 208 3,076 8/18/2015 14:10 Dog Park Underdrain grab >24,200 10/23/2015 12:30 Dog Park Underdrain grab 11,531 11/17/2015 8:00 Dog Park Underdrain grab 5,650

The limited TP and TSS samples indicate moderate TP and relatively high TSS. In the field, grab samples appeared tan and cloudy. It is likely that fine particulates washing off the crushed gravel caused the high TSS values. The TP values are similar to other values found in stormwater. For comparison, the event mean concentration from the MPRB NPDES data from 2001 through 2015 of TP ranged from a low of 0.313 mg/L to a high of 0.583 mg/L, similar to the two dog park samples, and TSS ranged from a low of 70 mg/L to a high of 180 mg/L, lower than the dog park samples.

2015 Water Resources Report – Minneapolis Park & Recreation Board Page 27-4 Table 27-3 shows the 2015 NPDES site E. coli geometric mean data for comparison with the Lyndale Dog Park samples. The NPDES sites, E. coli data, were all lower than the Lyndale Dog Park but the 14th and Park site (a mixed use site) was close to the level of bacteria in the Lyndale Dog Park. The two Lyndale Dog Park samples with “greater than” data were used as those values, with the greater than symbol removed.

Table 27-3. The 2015 NPDES E. coli comparison to the Lyndale Dog Park. Bacteria are sampled quarterly at the other NPDES representative land use sites. 2015 E. col i Geometric Site Land Use Mean 22nd Aldrich Residential 3,301 14th Park Mixed Use 7,394 61st Lyndale Industrial 1,441 Lyndale Dog Park Dog Park 8,339

In order to better characterize the Lyndale Dog Park E. coli in stormwater runoff, more bacteria grab samples will need to be collected and analyzed in 2016. Due to the limited number of TP and TSS samples additional samples will also be collected in 2016 to better understand and characterize these parameters.

2015 Water Resources Report – Minneapolis Park & Recreation Board Page 27-5 28. GOLF COURSE WETLAND MONITORING

BACKGROUND

Environmental Stewardship assists the MPRB golf courses in water and vegetation monitoring. The Theodore Wirth and Meadowbrook Golf Courses have requested annual monitoring since 2001. In 2009 Columbia, Hiawatha, and Gross Golf Courses added environmental monitoring to their programs.

Golf Course Foremen assisted Water Resources Staff in choosing representative waterbodies on each course. A visual survey and identification of aquatic and wetland vegetation was conducted at each sample site. Physical parameters (temperature, conductivity, pH, and dissolved oxygen) were measured with a Hydrolab Multiprobe. Water samples were collected and taken to Instrumental Research, Inc. for laboratory analysis of chemical parameters (total phosphorus, nitrate/nitrite, and ammonia). Standard MPRB sampling and QA/QC procedures were followed. This report details the last five years of data and older data can be found in previous reports.

COLUMBIA GOLF COURSE

Three ponds on the Columbia Golf Course were chosen for monitoring and are shown in Figures 28- 1 and 28-2. The headwaters pond is just off of Hole 4 (Pond 1). Pond 1 receives water from a groundwater well used to irrigate the golf course and has clear water all year. Pond 2 (the Driving Range Pond) receives surface drainage from the driving range and drains to an unsampled pond downstream of Pond 1. Pond 3 is the last pond in the series and outlets to a low area before entering a stormsewer that drains to the Mississippi River.

Columbia Golf Club Sampling Location Water

0250500 Meters

Driving Range Pond Hole 4 Pond

Outlet Pond

Figure 28-1. Sample sites on the Columbia Golf Club course.

2015 Water Resources Report – Minneapolis Park & Recreation Board Page 28-1

Pond 1, Hole 4 Pond 2, Driving Range Pond 3, Outlet Pond

Figure 28-2. Photographs of sample sites on the Columbia Golf Club course.

Columbia Golf Course has been monitored since 2009. Aquatic, terrestrial, and wetland plants in the ponds and surrounding buffers were surveyed in mid-August. A few new plant species were discovered around each pond, especially Pond 3. Cattails, Smartweeds and Stinging Nettles are the most prevalent species surveyed in the past five years. Only one new species from the Polygonaceae or Smartweed family was discovered. Dominant species identified from the Columbia Golf Course ponds and buffer zones are presented in Table 28-1.

2015 Water Resources Report – Minneapolis Park & Recreation Board Page 28-2

Table 28-1. Dominant plants within and surrounding the Columbia Golf Course Ponds.

Columbia Golf Course Pond 1, Hole 4 Pond 2, Driving Range Pond Pond 3, Outlet Pond Scientific Name Common Name J u n - 11 J u l- 12 A u g - 13 J u l- 14 J u l- 15 J u n - 11 J u l- 12 A u g - 13 J u l- 14 J u l- 15 J u n - 11 J u l- 12 A u g - 13 J u l- 14 J u l- 15 Terrestrial and Wetland Species Agrostis gigantea Redtop XX Alisma subcordatum Water Plantain XX Ambrosia artemisiifolia Common Ragweed X Arctium minus Burdock X Asclepias incarnata M arsh M ilkweed XX Asclepias syriaca Common M ilkweed XX Aster spp Aster 1 XX XX Bidens cernua Beggarst ick X Brassica spp Mustard XX Bromus inermis Smooth Brome X Carex spp Sedge XX Cirsium spp Thistle XXX XXXXXXXXX Cyperus esculentus Yellow Nut Sedge X Eliocharis obtusa Sp ike Rush XX XXX Fraxinus Pennsylvanica Green Ash X Helenium autumnale Common Sneezeweed X Helianthus spp Sunflower X Nepta cataria Catnip XX X Parthenocissus quinquefolia Virginia Creeper XX Persicaria lapathifolia Nodding Smartweed X Poa pratensis Kentucky Bluegrass XX X XXXXX Polygonum pensylvanicum Smartweed XXX XXXXXX XXXXX Pontedaria cordata Pickerelweed XX Potentilla millegrana Diffuse Cinquefoil XX Potentilla norvegica Rough Cinquefoil XXXXXXX Rorippa palustris Common Yellowcress XX Rumex crispus Curled Dock XX X X X X XXX X XX Salix spp Sandbar Willow XX X X Schoenoplectus acutus Hardstem Bulrush X Scirpus fluviatilis River Bulrush XX Scirpus validus Soft stem Bulrush X Setaria veridis Foxtail X Sinapis spp Mustard XXX X Solanum dulcamara Bittersweet Nightshade XX X XX X Solidago spp Goldenrod XX X X X Typha spp Cattail XXX XXXXXXXXXXXX Ulmaceaespp Elm X Urtica dioica Stinging Nettle XXX XXXXXXXXX XX Verbena hastata Blue Vervain XXX XXXXX Vitus riparia Riverbank Grape XX X X X X

Aquatic Species Pond 1, Hole 4 Pond 2, Driving Range Pond Pond 3, Outlet Pond Scientific Name Common Name J u n - 11 J u l- 12 A u g - 13 J u l- 14 J u l- 15 J u n - 11 J u l- 12 A u g - 13 J u l- 14 J u l- 15 J u n - 11 J u l- 12 A u g - 13 J u l- 14 J u l- 15 Aquatic S pecies Filamentous algae Filamentous algae XXXX X Lemna minor Lesser Duckweed XXXXXXXXX X Potamogeton spp Narrow Leaf Pondweed XX XX Potamogeton zosteriformis Flat Stem Pondweed X Vallisneria americana Water Celery X Wolfia colombiana Wolfia XX

2015 Water Resources Report – Minneapolis Park & Recreation Board Page 28-3 Water quality monitoring results for Columbia Golf Course are shown in Table 28-2. Dissolved oxygen was not recorded in 2015 due to technical difficulties. Pond 1 receives aerated water from a groundwater well. The DO concentration in Pond 1is typically relatively high and stable. Groundwater may be responsible for a lower than expected water temperature in Pond 1.

Table 28-2. Water quality monitoring results for Columbia Golf Course. NS = not sampled. Temp DO% DO pH SpCond TP NH3 NO3/NO2 Colombia Date Time °C Sat mg/l Units µS/cm mg/L mg/L mg/L Pond 1 - Hole 4 6/29/2011 10:20 21.3 109.6 9.48 7.3 1300 0.018 <0.500 0.042 Pond 1 - Hole 4 7/17/2012 10:35 16.7 84.2 7.90 7.6 1482 0.029 0.416 0.090 Pond 1 - Hole 4 8/15/2013 10:00 14.9 83.3 8.23 8.1 1615 0.058 0.871 <0.030 Pond 1 - Hole 4 7/30/2014 10:30 16.3 82.4 7.87 7.5 1633 0.057 0.684 0.064 Pond 1 - Hole 4 7/23/2015 10:20 17.8 NS NS 7.63 1538 0.034 <0.500 0.137 Pond 2 - Driving Range 6/29/2011 10:35 15.7 7.6 0.73 7.6 754 1.27 3.36 <0.030 Pond 2 - Driving Range 7/17/2012 NS NS NS NS NS NS NS NS NS Pond 2 - Driving Range 8/15/2013 10:15 19.6 8.7 0.78 7.7 1357 2.24 6.23 <0.030 Pond 2 - Driving Range 7/30/2014 10:50 19.6 0.0 0.00 7.2 926 0.67 1.53 1.28 Pond 2 - Driving Range 7/23/2015 10:30 21.4 NS NS 7.47 593 0.536 1.55 0.036 Pond 3 - Outlet 6/29/2011 10:45 23.5 80.9 6.73 7.4 837 0.389 2.61 0.033 Pond 3 - Outlet 7/17/2012 NS NS NS NS NS NS NS NS NS Pond 3 - Outlet 8/15/2013 10:25 19.2 111.3 10.04 7.2 1591 0.058 3.37 0.063 Pond 3 - Outlet 7/30/2014 11:00 20.7 13.7 1.19 7.2 1372 0.847 3.33 2.58 Pond 3 - Outlet 7/23/2015 10:50 25.3 NS NS 7.40 1595 0.357 2.63 0.131

Pond 2 historically has low levels of DO due to eutrophication. In 2014 Pond 2 became completely anoxic, although nutrient levels have dropped significantly since 2013. Nutrient concentrations remained lower historic levels in 2015.

Pond 3 also experienced a significant decline in DO in 2014. Nitrates and nitrites were unusually high that year. The decomposition of organic material deposited by major 2014 flooding may have reduced DO in Pond 3. Nitrate and nitrite concentrations were lower in 2015, but higher than historic levels.

The amount of NH3 in all ponds has risen over the past few years. Ponds 2 and 3 are quite high. The increase in NH3 may be indicative of increased nutrient inputs or increased organic decay. Chemical parameters, total phosphorus, ammonia, and nitrate/nitrite were analyzed by IRI, Inc.

2015 Water Resources Report – Minneapolis Park & Recreation Board Page 28-4 GROSS NATIONAL GOLF COURSE

Three ponds and one additional vegetation monitoring site were chosen on Gross National Golf Course presented in Figures 28-3 and 28-4. Pond 7 is one of the oldest water bodies on the golf course and may be a remnant of a natural wetland. The pond is hydrologically isolated, with no drain tile outlets and no connection to the golf course irrigation system. Ponds 14 and 12 were constructed in the mid-1990s to help improve drainage on the golf course.

Figure 28-3. Sample sites on the Gross National Golf Course.

Pond 7 Pond 12 Pond 14

Figure 28-4. Photographs of sample sites on the Gross National Golf Course.

2015 Water Resources Report – Minneapolis Park & Recreation Board Page 28-5 Drain tile from the surrounding fairways leads to each of these ponds. Groundwater for irrigation of the golf course is pumped to Pond 14. Pond 14 drains to Pond 12 and Pond 12 can be pumped to the site marked Low Area in Figure 28-3. A “low area” was chosen as an additional vegetation survey site since water is pumped to it and it had different vegetation than most of the golf course. But the “low area” has not had water in it the last few years.

Gross Golf Course has been monitored since 2009. Aquatic, terrestrial and wetland plants in the ponds and surrounding buffer zones were surveyed at the end of July. Curled Dock, Kentucky Bluegrass and Sandbar Willow were the most prevalent species surveyed in the past five years. No new species were discovered. Dominant plants identified at the Gross National Golf Course ponds and buffer zones are presented in Table 28-3.

2015 Water Resources Report – Minneapolis Park & Recreation Board Page 28-6 Table 28-3. Dominant plants at the Gross National Golf Course sample sites.

Gross Golf Course Pond 7 Pond 12 Pond 14 Low Area Scientific Name Common Name J u n - 11 J u l- 12 Au g - 13 J u l- 14 J u l- 15 J u n - 11 J u l- 12 Au g - 13 J u l- 14 J u l- 15 J u n - 11 J u l- 12 Au g - 13 J u l- 14 J u l- 15 J u n - 11 J u l- 12 Au g - 13 J u l- 14 J u l- 15 Terrestrial and Wetland Species Acer saccharinum Silver Maple XXX Achillea millefolium Yarrow XX Ajuga reptans Bugleweed X Alnus incana Speckled Alder XX X XX Ambrosia spp Ragweed XX Arctium ssp Burdock X Asclepcias incarnata Marsh Milkweed XX Asclepcias syriaca Common Milkweed XX Aster lanceolatus Marsh Aster X Aster spp Aster XXX Brassica rapa Field Mustard X Bromus inermis Smooth Brome Carex spp Sedge XX X XX Carex spp Sedge 2 X Circaea spp Enchanter's Nightshade XX Cirsium spp Thistle XX XXX XXXX Cirsium avense Canadian T histle XX X XX XX Cyperus esculentus Yellow Nutsedge XX Cyperus odoratus Flat sedge X Daucus carota Queen Anne's Lace XX Erigeron annuus Daisy fleabane X Echinochloa crusgalli Barnyard Grass XX Eloecharis obtusa Blunt Spikerush XXX XX X Eupatorium perfoliatum Boneset XX X Fraxinus pennsylvanica Green Ash XX Helenium autumnale Sneezeweed X Juncus tenuis Slen der Rush X Leonurus cariaca Motherwort X Lycopus americanus American bugleweed X Lythrum salicaria Purple Loosestrife XX X Mim ulus ringens Square-stemed Monkeyflower XX Parthenocissus quinquefolia Virginia Creeper X Phalaris arundinacea Reed Canary Grass XX X X XX X XX X XX Poa pratensis Kent ucky Bluegrass XXXXXXXXX XXXX Polygonum pensylvanicum Sm ar t weed XXX XX X X Populus deltoides Eastern Cottonwood XX Populus tremuloides Aspen XXXX XXXX Potentilla norvegica Rough Cinquefoil XX Rhamnus cathartica Common Buckthorn XXX Rudbeckia hirta Black eyed susan XXXX Rumex crispus Curled Dock XX X X XXX X XX X XX XX Sagittaria latifolia Broad-leaved Arrowhead XX XXXXXX XXX X Salix spp Weeping Willow XX X X X Salix spp Sandbar Willow (?) XXX X XX X X XX X XX Salix nigra Black Willow XX Schoenoplectus acutus Hardstem Bulrush XX Scripus atrovirens Green Bulrush X Scirpus cyperinus Woolgrass XX Scirpus fluviatilis River Bulrush XXXXXXXXX X Scirpus validus So f t st em Bulr ush X Scutellaria galericulata Marsh Skullcap XX Solanum dolcamara Bit t ersweet Night shade XX X Sonchus ssp So w T h ist le XX Setaria veridis Foxtail XXX X Sinapis spp Mustard XX Solidago canadensis Canada goldenrod XXX X XX Sonchus oleraceus Common Sow-thistle XX Typha spp Cattail XXXXXXXXXX Urtica dioica Stinging Nettle XX Verbena hastata Blue Vervain XX XXX Verbena urticifolia White Vervain X Vitus riparia Riverbank Grape XX X

Aquatic Species Pond 7 Pond 12 Pond 14 Low Area Scientific Name Common Name J u n - 11 J u l- 12 Au g - 13 J u l- 14 J u l- 15 J u n - 11 J u l- 12 Au g - 13 J u l- 14 J u l- 15 J u n - 11 J u l- 12 Au g - 13 J u l- 14 J u l- 15 J u n - 11 J u l- 12 Au g - 13 J u l- 14 J u l- 15 Aquatic Species Ceratophyllum demersum Coontail X Filamentous algae Filamentous algae XX X Lemna minor Lesser Duckweed X X XXXXX XX Potamogeton spp Pondweed 1 X Potamogeton pectinatus Sago Pondweed X Riccia fluitans Slender Riccia X Spirodela polyrhiza Big Duckweed XX Wolfia colombiana Wolfia X

2015 Water Resources Report – Minneapolis Park & Recreation Board Page 28-7

Water quality monitoring results for Gross Golf Course are shown in Table 28-4. Dissolved oxygen was not recorded in 2015 due to technical difficulties. Pond 7 has become anoxic over the past five years, although the most significant decline occurred in 2013, a year that also showed relatively high levels of phosphorus and ammonia. This may indicate that increased nutrients caused eutrophication in Pond 7.

Table 28-4. Water quality monitoring results for Gross National Golf Course.

Temp DO% DO pH SpCond TP NH3 NO3/NO2 Gross Date Time °C Sat mg/l Units µS/cm mg/L mg/L mg/L Pond 7 6/29/2011 9:15 20.8 104.4 9.16 8.5 352 0.583 <0.500 0.036 Pond 7 7/17/2012 9:25 26.6 69.8 5.42 7.5 441 1.08 0.982 <0.030 Pond 7 8/15/2013 8:50 18.9 5.1 0.47 6.8 412 1.60 1.02 <0.030 Pond 7 7/30/2014 9:00 21.0 1.8 0.15 7.3 360 0.81 <0.500 0.485 Pond 7 7/22/2015 9:00 23.5 NS NS 7.58 351 0.51 0.629 <0.030 Pond 12 6/29/2011 9:40 21.1 66.6 5.81 7.2 367 0.071 <0.500 0.033 Pond 12 7/17/2012 9:45 26.1 77.3 6.06 7.8 427 0.138 0.081 <0.030 Pond 12 8/15/2013 9:15 19.1 12.7 1.15 6.7 346 0.320 1.01 <0.030 Pond 12 7/30/2014 9:40 20.5 21.1 1.86 7.4 289 0.119 <0.500 <0.030 Pond 12 7/22/2015 9:45 25.7 NS NS 7.60 447 0.222 <0.500 <0.030 Pond 14 6/29/2011 9:30 21.3 91.7 7.97 7.7 454 0.083 <0.500 <0.030 Pond 14 7/17/2012 9:35 25.8 53.5 4.21 7.6 443 0.198 0.107 <0.030 Pond 14 8/15/2013 9:10 18.1 95.9 8.90 7.6 385 0.075 0.637 <0.030 Pond 14 7/30/2014 9:30 20.1 85.9 7.62 7.9 391 0.244 <0.500 <0.030 Pond 14 7/22/2015 23.0 NS NS 7.70 448 0.344 <0.500 0.037 9:30

Pond 12 shows a decreasing trend in DO while Pond 14 remains stable. Phosphorus concentrations increased in both ponds in 2015, while ammonia, nitrates and nitrites remained nearly the same. Chemical parameters such as total phosphorus, ammonia, and nitrate/nitrite were analyzed by IRI, Inc.

2015 Water Resources Report – Minneapolis Park & Recreation Board Page 28-8 HIAWATHA GOLF COURSE

Four sample sites were chosen at the Hiawatha Golf Course, Figures 28-5 and 28-6. Ponds 1, 2, and 3 are part of an interconnected chain of ponds that pump water to Lake Hiawatha. It is believed the chain of ponds is pumped down every day throughout the year. Several sources contribute water to the pond chain. Groundwater and drain tile are the two local sources of water to these ponds. Additionally, during precipitation events stormwater from neighborhood streets overflows to the Hiawatha pond chain. To alleviate flooding, the area covering the course’s parking lot is now pumped to Pond 1. Over the next several years, additional upstream neighborhood stormwater may be piped to Pond 1. Pond 4 is not connected to the chain of ponds and is isolated. Prior to zebra mussels entering Lake Hiawatha the golf course occasionally pumped water from Lake Hiawatha to Pond 4.

Figure 28-5. Sample sites on the Hiawatha Golf Course.

2015 Water Resources Report – Minneapolis Park & Recreation Board Page 28-9 Pond 1 Pond 2

Pond 3 Pond 4

Figure 28-6. Photographs of sample sites on the Hiawatha Golf Course.

Hiawatha Golf Course has been monitored since 2009. Aquatic, terrestrial and wetland plants in the ponds and surrounding buffer zones were surveyed at the end of July. Hiawatha Golf Course continues to recover from the severe flooding of 2014 with the vegetation recovering. Kentucky Bluegrass, Reed Canary Grass and Cattails were the most prevalent species surveyed in the past five years. No new species were discovered. Dominant plants from the Hiawatha Golf Course ponds and buffer zones are presented in Table 28-5.

2015 Water Resources Report – Minneapolis Park & Recreation Board Page 28-10 Table 28-5. Dominant plants within and surrounding the Hiawatha Golf Course sample sites.

Hiawatha Golf Course Pond 1Pond 2Pond 3Pond 4 Scientific Name Common Name J u l- 11 N S A u g - 13 J u l- 14 J u l- 15 J u l- 11 N S A u g - 13 J u l- 14 J u l- 15 J u l- 11 N S A u g - 13 J u l- 14 J u l- 15 J u l- 11 N S A u g - 13 J u l- 14 J u l- 15 Terrestrial and Wetland Species Acer spp Maple (saplings) X XXX XXX XX Alnus incana Speckled Alder X Ambrosia artemisiifolia Common Ragweed X XX XXX X Ambrosia trifida Giant Ragweed XX XX Asclepias incarnata Marsh Milkweed X Asclepias spp M ilkweed X XX Asclepias syriaca Common M ilkweed X Aster spp Aster XXXX Carex comosa Bottlebrush Sedge X Carex spp Sedge X XXX X Cirsium spp Thistle XX XX X Eloecharis obtusa Blunt Spikerush XXX Eupatorium perfoliatum Common Boneset X Fraxinus pennsylvanica Green Ash XX Gleditsia triacanthos Honey Locust X Impatiens pallida Pale Jewel Weed XX Larix laricina Tamarack X XXX Lythrum salicaria Purple Loosestrife X Menispermum canadence M oonseed X Phalaris arundinacea Reed Canary Grass X XXXX XXXX XXX Poa pratensis Kentucky Bluegrass X XXXX XXXX XXXX XXX Polyganum perfoliatum Tearthumb XX X XX Polygonum hydropier Smartweed XX Rubus spp Raspberry (?) X Rumex crispus Curled Dock X X XX XXXX X Sagiteria latifolia Broad-leaf Arrowhead X XXX Salix spp Sandbar Willow (?) XX XXX Scirpus atrovirens Green Bulrush X X Scirpus fluviatiis River Bulrush XXX XX Scirpus validus Softstem Bulrush XX Solidago spp Goldenrod X XXXX Sonchus oleraceous Common Sow Thistle XXX XXX Typha spp Cattail X XXXX XXX XXX Unknown Annual Weeds X XXX Urtica diotica Stinging Nettle X XXX Verbena hastata Blue Vervain X

Aquatic S pecies Pond 1Pond 2Pond 3Pond 4 Scientific Name Common Name J u l- 11 N S A u g - 13 J u l- 14 J u l- 15 J u l- 11 N S A u g - 13 J u l- 14 J u l- 15 J u l- 11 N S A u g - 13 J u l- 14 J u l- 15 J u l- 11 N S A u g - 13 J u l- 14 J u l- 15 Aquatic S pecies Ceratophyllum demersum Coontail XX XX Chara spp Muskgrass X Elodea canadensis Canadian Waterweed XX X Lemna minor Lesser Duckweed X XXX Najas flexalis Bushy Pondweed X Nymphaea odorata White Water Lily X Potamogeton foliosus Narrow Leaf Pondweed XXX X XX Potamogeton natans Floating Leaf Pondweed X Potamogeton pectinatus Sago Pondweed XXX

2015 Water Resources Report – Minneapolis Park & Recreation Board Page 28-11

Water quality monitoring results for Hiawatha Golf Course are shown in Table 28-6. Ponds 1, 2 and 3 remain saturated with dissolved oxygen in 2015. Nutrient levels in all four ponds decreased in 2015, possibly due to previous flooding in 2014. Hiawatha was not sampled in 2012. Chemical parameters, total phosphorus, ammonia, and nitrate/nitrite were analyzed by IRI, Inc.

Table 28-6. Water quality monitoring results for Hiawatha Golf Course. NS = no sample.

Temp DO% DO pH SpCond TP NH3 NO3/NO2 Hiawatha Date Time °C Sat mg/l Units µS/cm mg/L mg/L mg/L Pond 1 7/1/2011 9:06 27.1 118.0 9.09 7.4 636 0.036 <0.500 0.034 Pond 1 2012 NS NS NS NS NS NS NS NS NS Pond 1 8/16/2013 9:30 21.4 129.2 11.21 7.9 598 0.046 <0.500 <0.030 Pond 1 7/31/2014 9:50 23.1 93.6 7.82 7.8 668 0.179 <0.500 0.081 Pond 1 7/29/2015 9:30 27.3 136.7 10.52 8.11 679 0.108 <0.500 <0.030 Pond 2 7/1/2011 9:20 22.6 74.3 6.21 7.1 975 0.032 0.743 2.02 Pond 2 2012 NS NS NS NS NS NS NS NS NS Pond 2 8/16/2013 9:20 16.9 65.1 6.18 7.2 986 0.039 0.660 0.622 Pond 2 7/31/2014 10:10 18.6 149.5 13.63 7.5 1004 0.150 <0.500 2.31 Pond 2 7/29/2015 9:45 24.5 125.9 10.19 7.72 905 0.084 <0.500 0.355 Pond 3 7/1/2011 9:30 26.4 139.8 10.90 7.5 862 0.045 1.33 0.616 Pond 3 2012 NS NS NS NS NS NS NS NS NS Pond 3 8/16/2013 9:10 18.9 70.9 6.45 7.4 936 0.073 0.590 0.54 Pond 3 7/31/2014 10:20 21.0 94.2 8.17 7.5 952 0.193 0.760 0.390 Pond 3 7/29/2015 10:00 24.1 98.9 8.07 7.67 909 0.102 <0.500 0.213 Pond 4 7/1/2011 9:35 24.5 24.6 1.99 6.8 987 0.055 3.44 0.532 Pond 4 2012 NS NS NS NS NS NS NS NS NS Pond 4 8/16/2013 8:55 18.3 20.9 1.93 7.1 937 0.118 1.27 0.771 Pond 4 7/31/2014 10:30 18.1 21.1 1.94 7.1 996 0.240 2.81 2.66 Pond 4 7/29/2015 10:30 23.7 108.5 8.92 7.64 873 0.174 0.706 0.232

Although the chain of ponds is interconnected and pumped daily, each pond retains its own character. Their differences can be seen both visually and chemically. Pond 4 is isolated and has continually exhibited distinctly higher phosphorus and ammonia levels than other ponds. Pond 4’s high nutrient condition could be due to its isolation and lack of flushing.

2015 Water Resources Report – Minneapolis Park & Recreation Board Page 28-12 MEADOWBROOK GOLF COURSE

Four water bodies were monitored at Meadowbrook Golf Course: Meadowbrook Lake, Wetland C, Wetland L, and Wetland N, Figures 28-7 and 28-8. The wetland’s alphabetic labels are derived from nomenclature used by Meadowbrook Golf Course.

Figure 28-7. Meadowbrook Golf Course water quality and vegetation monitoring locations.

Meadowbrook Lake Wetland C

Wetland L Wetland N

Figure 28-8. Photographs of Meadowbrook Golf Course water quality and vegetation monitoring locations.

2015 Water Resources Report – Minneapolis Park & Recreation Board Page 28-13 Each of the sampled water bodies on the Meadowbrook Golf Course has unique hydrologic characteristics. Wetland C is the furthest upstream sample site and only receives runoff from the surrounding course. Wetland N is near the course edge and receives stormwater from the neighborhood in order to reduce the risk of flooding in homes. Wetland L is a deep pond and receives water that is pumped from all the other wetlands prior to discharge into Meadowbrook Lake. Minnehaha Creek flows through Meadowbrook Lake.

Meadowbrook Golf Course has been monitored since 2000. Aquatic, terrestrial and wetland plants in the ponds and surrounding buffer zones were surveyed at the end of July. Meadowbrook Golf Course continues to be effected by the flooding of 2014. Wetland L and the area surrounding it remains unmanaged after the 2014 flood and was therefore inaccessible for monitoring in 2015. Reed Canary Grass, Hybrid Cattails and Kentucky Bluegrass were the most prevalent species surveyed in the past five years. One new species, Conyza canadensis or Horseweed, was observed. Older data can be found in previous reports. All species identified from Meadowbrook Golf Course are presented in Table 28-7.

2015 Water Resources Report – Minneapolis Park & Recreation Board Page 28-14 Table 28-7. Dominant plants surrounding the Meadowbrook Golf Course sample sites.

Meadowbrook Golf Course Wetland C Wetland N Wetlant L Medowbrook Lake Scientific Name Common Name J u n - 11 J u l- 12 A u g - 13 J u l- 14 J u l- 15 J u n - 11 J u l- 12 A u g - 13 J u l- 14 J u l- 15 J u n - 11 J u l- 12 A u g - 13 J u l- 14 J u l- 15 J u n - 11 J u l- 12 A u g - 13 N S J u l- 15 Wetland and Upland S pecies Acer ginnala Amur maple XXX Ajuga spp Bugleweed X Andropogon gerardii Big Bluestem XX X Arctium minus Burdock XX X Asclepias incarnata Marsh Milkweed XX X Asclepias syriaca Common M ilkweed XX X Aster lanceolatus Marsh Aster XXX Asteraceae sonchus Sow Thistle X Bromus spp Brome Grass X Carex spp Sedge sp p XXXX X Carex meadii M ead's Sedge X Cirsium avense Canadian Thistle XX X X X XX Conyza canadensis Horseweed X Echinochloa crusgalli Barnyardgrass XX Echinocystis lobata Wild Cucumber XX Eleocharis acicularis Needle spike-rush XX X Eupatorium perfoliatum Boneset X Eupatorium purpureum Joe Pye weed X Fraxinus pennsylvanica Green Ash XXX XX Helenium autumnale Common Sneezeweed XX Helianthus grosseserratus Sawtooth Sunflower X Impatiens capensis Orange Jewelweed XX X X Leersia oryzoides Rice cutgrass X Leonurus cariaca Motherwort XX Lycopus americanus American Bugleweed XX X Lycopus spp. Bugleweed X Lythrum salicaria Purple Loosestrife XX Melilotus albus medikus Sweet White Clover XX Monarda Bee Balm X Parthenocissus quinquefolia Virginia Creeper X X Persicaria lapathifolia Nodding Smartweed X Phalaris arundinacea Reed Canary Grass XX XXXXX X XXX X XX X Poa pratensis Kentucky Bluegrass XX X XX X XX X Polygonum amphibium Water Smartweed XXX Polygonum hydropier Common Smartweed XX Polygonum persicaria Ladies Thumb X Populus deltoides Eastern Cottonwood XX X XXX Populus ssp Aspen X Potentilla norvegica Rough Cinquefoil XXX Rhamnus cathartica Buckthorn XX Rubus strigosus Raspberry X Rudbeckia hirta Black eyed susan XX X X Rumex crispus Curled dock XX XXXX Salix exigua Sandbar Willow XX X XXX X Salix nigra Black Willow XX XXXX X Schoenoplectus acutus Hardstem Bulrush XX Scirpus atrovirens Green Bulrush XX XX X Scirpus fluviatilis River Bulrush X Scirpus validus Soft stem Bulrush X Scutellaria galericulata Marsh Skullcap XX Sedge spp. Sedge sp p X Solanum dulcamara Bittersweet Nightshade XX XXX Solidago canadensis Canada Goldenrod XX Sonchus oleraceus Common Sow-thistle XX X Sparganium eurycarpum Common Bur-reed XX X XX X Spartina pectinata Prairie cordgrass XX X Typha angustifolia Narrow leaved cattail XXXX Typha latifolia Broad-leaved cattail XXXX XX XXX Typha X glauca Hybrid Cattail XX XXX XXX XXX Ulmus pumilla Siberian Elm XX X Urtica dioica Stinging Nettle XX XX XX Verbena hastata Blue vervain XX Vicia cracca Cow Vetch XX X XXX Vitus riparia Riverbank Grape XX XXX XXX Zizea aurea Golden Alexanders X

Aquatic S pecies Wetland C Wetland N Wetland L Medowbrook Lake Scientific Name Common Name J u n - 11 J u l- 12 A u g - 13 J u l- 14 J u l- 15 J u n - 11 J u l- 12 A u g - 13 J u l- 14 J u l- 15 J u n - 11 J u l- 12 A u g - 13 J u l- 14 J u l- 15 J u n - 11 J u l- 12 A u g - 13 N S J u l- 15 Floating S pecies Lemna minor Lesser Duckweed XXXXXX XXX X XXX X Spirodela polyrhiza Big duckweed XX XXXX X XXXX Wolffia columbiana Watermeal XXXX X S ubmerged S pecies Ceratophyllum demersum Coontail X XX X Elodea canadensis Common Waterweed X X Myriophyllum spicatum Eurasian Watermilfoil X Potamogeton berchtoldii Narrow leaved pondweed X Potamogeton crispus Curly-leaf pondweed XX Potamogeton pectinatus Sago Pondweed X Potamogeton zosteriformis Flat-stem pondweed XX Vallisneria americana Water celery X

2015 Water Resources Report – Minneapolis Park & Recreation Board Page 28-15 Water quality monitoring results for Meadowbrook Golf Course are shown in Table 28-8. Wetland L and the area surrounding it remains unmanaged after the 2014 flood and was therefore inaccessible for monitoring. Dissolved oxygen was not recorded in 2015 due to technical difficulties. Specific conductivity decreased in Wetland C and Wetland N in 2015. Wetland C and Wetland N historically have low levels of dissolved oxygen due to the abundance of organic decomposition typical of wetland ecosystems. Chemical parameters, total phosphorus, ammonia, and nitrate/nitrite were analyzed by IRI, Inc.

Table 28-8. Water quality monitoring results for Meadowbrook Golf Course. NS = no sample.

Temp DO% DO pH SpCond TP NH3 NO3/NO2 Meadowbrook Date Time °C Sat mg/l Units µS/cm mg/L mg/L mg/L Meadowbrook Lake 6/30/2011 10:50 25.2 112.3 8.98 7.6 414 NS NS NS Meadowbrook Lake 7/19/2012 9:45 26.1 63.7 5.04 7.4 493 0.104 0.313 0.093 Meadowbrook Lake 8/13/2013 9:25 22.9 60.9 5.13 7.6 445 0.030 0.714 <0.030 Meadowbrook Lake 7/29/2014 NS NS NS NS NS NS NS NS NS Meadowbrook Lake 7/21/2015 9:00 25.0 NS NS 8.07 608 0.034 <0.500 <0.030 We tl and C 6/30/2011 10:30 22.6 14.6 1.23 6.8 286 0.133 <0.500 0.031 We tl and C 7/19/2012 8:55 22.8 3.9 0.33 6.7 347 0.235 1.34 <0.030 We tl and C 8/13/2013 9:00 18.7 2.3 0.21 6.8 218 0.130 0.794 <0.030 We tl and C 7/29/2014 9:45 20.8 4.6 0.41 7.0 544 0.767 1.13 0.078 We tl and C 7/21/2015 9:15 27.4 NS NS 7.98 188 0.142 0.651 <0.030 We tl and L 6/30/2011 11:00 19.5 11.9 1.06 6.8 707 0.341 1.27 0.087 We tl and L 7/19/2012 9:45 19.8 6.8 0.61 7.2 823 0.353 2.59 <0.030 We tl and L 8/13/2013 9:35 16.1 3.5 0.34 7.0 875 0.206 2.29 0.131 We tl and L 7/29/2014 10:25 23.5 14.8 1.23 7.4 516 0.290 <0.500 0.052 We tl and L 7/21/2015 9:30 NS NS NS NS NS NS NS NS We tl and N 6/30/2011 10:45 23.0 3.7 0.31 6.8 371 0.185 <0.500 <0.030 We tl and N 7/19/2012 9:15 23.2 4.0 0.33 7.0 335 0.811 1.48 <0.030 We tl and N 8/13/2013 9:15 19.3 5.0 0.45 7.0 373 0.201 0.771 <0.030 We tl and N 7/29/2014 10:15 22.4 18.2 1.55 7.4 417 0.325 <0.500 <0.030 We tl and N 7/21/2015 10:00 26.0 NS NS 7.93 318 0.152 0.750 <0.030

2015 Water Resources Report – Minneapolis Park & Recreation Board Page 28-16 THEODORE WIRTH GOLF COURSE

Three sample sites were chosen at Theodore Wirth Golf Course. The inlet and outlet of Bassett Creek are monitored in order to assess how the golf course affects stream water quality. The Par 3 wetland is unconnected to Bassett Creek and is located adjacent to a recently developed housing complex and accepts stormwater from this region. The wetland has experienced an increase in the volume in stormwater runoff since monitoring began. Figure 28-9 and Figure 28-10 shows the location of the monitoring sites on the golf course.

Figure 28-9. Wirth Golf Course water quality and vegetation monitoring locations.

Bassett In Bassett Out Par 3 Wetland

Figure 28-10. Photographs of Wirth Golf Course water quality and vegetation monitoring locations.

2015 Water Resources Report – Minneapolis Park & Recreation Board Page 28-17 Theodore Wirth Golf Course has been monitored since 2000. Aquatic, terrestrial and wetland plants in the ponds and surrounding buffers were surveyed at the end of July. Reed Canary Grass, Sandbar Willow, and Kentucky Bluegrass were the most prevalent species surveyed in the past five years. Two new species, Euphorbia esuela or Leafy Spurge and Rumex crispus or Curled Dock, were surveyed this year. All species identified from Theodore Wirth Golf Course are presented in Table 28-9.

2015 Water Resources Report – Minneapolis Park & Recreation Board Page 28-18 Table 28-9. Dominant plants at the Wirth Golf Course sample sites.

Wirth Golf Course Bassett IN Bassett Out Par 3 Wetland

S c ie ntific Name Co mmo n Name J u n - 11 J u l- 12 A u g - 13 J u l- 14 J u l- 15 J u n - 11 J u l- 12 A u g - 13 J u l- 14 J u l- 15 J u n - 11 J u l- 12 A u g - 13 J u l- 14 J u l- 15 Wetland and Upland Vegetation Acer negundo Box Elder X Achillea millefolia Yarrow XXX X Ambrosia artemisiifolia Common Ragweed XXX XXX X Ambrosia trifada Giant Ragweed X Asclepias syriaca L. Common Milkweed XXX X Bidens spp Beggars Tick X Bromus spp Smooth Brome XXX X Calamagrostis canadensis Bluejoint Grass Carex hystericina Muhl. Porcupine Sedge X Cirsium avense Canadian Thistle XXX X X Eleocharis obtusa Blunt Spikerush X Elymus repens Quack Grass X Euphorbia esuela Leafy Spurge X Impatiens pallida Pale Jewelweed X Leonurus cardiaca Motherwort XX Linaria vulgaris Butter and eggs XX Lythrum salicaria Purple Loosestrife XX Melilotus officinalis Sweet Clover XX Mimulus ringens Square-stemmed Monkeyflower X Oxalis ssp Wood Sorrel X Parthenocissus quinquefolia Virginia Creeper XX X X Phalaris arundinacea Reed Canary Grass XXXX X XXXXXXXXXX Phleum pratense Timothy Grass X Plantago major Common Plantain X Poa pratensis Kentucky Bluegrass XXX X X X XX Polygonum amphibium Water Smartweed XXXX Polygonum persicaria Lady's Thumb XX XXX Populus deltoides Eastern cottonwood XXX Rhamnus cathartica Buckthorn XXX Ribes spp Currant X Rumex crispus Curled Dock X Rudbeckia ssp Cone Flower X Salix babalonica Weeping willow XXXX Salix exigua Sandbar willow XXX X X XXX XXX X XX Salix nigra Black willow XXX X Solidago candidensis Canada Goldenrod XX X X X Solidago spp. Goldenrod XX X Sonchus arvensis Sow Thistle XX X Typha angustifolia Narrow leaved cattail X Typha latifolia Broad leaved cattail XXXXX Typha X glauca Hybrid cattail XXXX Urtica dioica Stinging nettle XXX Vitus riparia Riverbank Grape XXX X

Aquatic S pecies Bassett IN Bassett OUT Par 3 Wetland Scientific Name Common Name J u n - 11 J u l- 12 A u g - 13 J u l- 14 J u l- 15 J u n - 11 J u l- 12 A u g - 13 J u l- 14 J u l- 15 J u n - 11 J u l- 12 A u g - 13 J u l- 14 J u l- 15 Floating Species Lemna minor Lesser duckweed XXXXXX X Lemna trisulca Star duckweed XXX Nymphaea odorata White water lily XXX Riccia fluitans Floating slender liverwort XXX Spirodela polyrhiza Big duckweed XX Wolffia columbiana Watermeal XX X Submerged Species Ceratophyllum demersum Coontail XXXX Elodea canadensis Common Waterweed X Potamogeton nodusus Long-leaf pondweed XXXX Potamogeton pectinatus Sago Pondweed XXX Zosterella dubia Water Stargrass XXX X

2015 Water Resources Report – Minneapolis Park & Recreation Board Page 28-19 Water quality monitoring results for Meadowbrook Golf Course are shown in Table 28-10. Dissolved oxygen was not recorded in 2015 due to technical difficulties. However, the Bassett Creek inlet has shown consistently high concentrations of DO over time. While the Bassett Creek outlet and Par 3 Wetland has had lower DO levels.

Table 28-10. Water quality monitoring results for Wirth Golf Course.

Temp DO% DO pH SpCond TP NH3 NO3/NO2 Wirth Date Time °C Sat mg/l Units µS/cm mg/L mg/L mg/L Bassett In 6/30/2011 9:06 22.8 82.0 6.86 7.2 742 0.097 <0.500 0.214 Bassett In 7/19/2012 11:00 23.7 76.5 6.32 7.7 502 0.188 0.879 0.221 Bassett In 8/13/2013 10:35 19.2 80.2 7.25 7.8 880 0.072 0.760 0.196 Bassett In 7/29/2014 11:45 20.5 94.9 8.37 7.8 821 0.074 <0.500 <0.030 Bassett In 7/21/2015 11:30 22.4 NS NS 7.59 305 0.068 <0.500 0.100 Bassett Out 6/30/2011 9:30 23.4 60.3 4.99 7.2 770 0.067 <0.500 0.097 Bassett Out 7/19/2012 11:25 24.8 42.0 3.40 7.7 471 0.153 0.274 0.158 Bassett Out 8/13/2013 11:15 22.0 39.3 3.36 7.5 867 0.085 0.840 0.110 Bassett Out 7/29/2014 12:25 21.2 0.0 0.00 7.6 810 0.099 <0.500 0.289 Bassett Out 7/21/2015 12:00 23.5 NS NS 8.04 721 0.088 <0.500 0.093 Par 3 Wetland 6/30/2011 8:55 22.6 11.9 1.00 6.8 396 0.101 <0.500 0.037 Par 3 Wetland 7/19/2012 10:40 23.0 10.3 0.86 7.5 438 0.350 1.01 <0.030 Par 3 Wetland 8/13/2013 11:00 20.6 1.2 0.11 7.0 422 0.422 1.15 <0.030 Par 3 Wetland 7/29/2014 11:15 22.3 11.5 0.98 7.3 334 0.231 <0.500 <0.030 Par 3 Wetland 7/21/2015 11:00 22.4 NS NS 7.86 706 0.367 0.915 <0.030

Phosphorus concentrations are also higher in the Bassett creek outlet than the inlet, suggesting that the water picks up some nutrients as it travels though the golf course. The Par 3 Wetland historically exhibits low amounts of dissolved oxygen, which is typical of a wetland with a high abundance of organic decomposition. However, specific conductivity for the Par 3 Wetland was higher in 2015. Stormwater from the housing complex (to the North) may have contributed dissolved solids and nutrients which could have discharged into the Par 3 Wetland. Chemical parameters, total phosphorus, ammonia, and nitrate/nitrite were analyzed by IRI, Inc.

2015 Water Resources Report – Minneapolis Park & Recreation Board Page 28-20 29. CLIMATOLOGICAL SUMMARY

NATIONAL WEATHER SERVICE DATA

Annual climate data is tracked and reported due to its year to year variability and significant impact on water resources. Table 29-1 shows total monthly precipitation and monthly average temperature for the year 2015 as recorded by the National Weather Service (NWS).

2015 was generally dry and warm for the first half of the year, and wet and warm the second half. The annual recorded precipitation total for 2015 was 36.14 inches, 0.46 inches above normal. The annual mean temperature was 48.3° F, 2.2° F above normal.

2015 had a very dry spring from January-June (with the exception of May and June), and wet from July-December (with the exception of August and December). The wettest month of the year was July, and the driest month of the year was March. The 2015 annual 0.27 inch departure from normal represents a near normal year, but individual months were above (3.28”) or below (1.31”) normal.

Table 29-1. Minneapolis precipitation, mean temperature and deviation from normal as recorded by the National Weather Service. Year Total Mean 2015 Precip. (inches) "Normal" Comparison: Temp. (F) "Normal" Comparison: January 0.34 0.56" below normal 19.0 3.4 F above normal February 0.35 0.42" below normal 11.2 9.6 F below normal March 0.67 1.22" below normal 35.5 2.7 F above normal April 2.42 0.24" below normal 49.7 2.2 F above normal May 3.55 0.19" above normal 59.2 0.1 F above normal June 4.40 0.15" above normal 69.7 0.9 F above normal July 7.32 3.28" above normal 73.4 0.4 F below normal August 2.99 1.31" below normal 70.7 0.5 F below normal September 4.65 1.57" above normal 67.9 5.9 F above normal October 2.61 0.18" above normal 52.1 3.2 F above normal November 4.52 2.75" above normal 41.4 7.7 F above normal December 2.32 1.16"below normal 30.2 10.5 F above normal Annual Data 36.14 0.27" above normal 48.3 2.2 F above normal

The 2015 NWS monthly data are plotted in Figure 29-1. In general the 2015 average monthly temperatures were above normal for nine months, and below for three months. Temperatures were significantly above normal September through December. The average annual temperature for 2015 was 48.3° F which was 2.2° F above normal.

In 2015 Figure 29-1 shows a very dry first half of the year, followed by a very wet second half of the year.

All NWS data was obtained from http://www.ncdc.noaa.gov/IPS/lcd/lcd.html?_page=1&state=MN&stationID=14922&_target2=Next+ %3E and the National Oceanic and Atmospheric Administration (NOAA) monthly publications. 2015 Water Resources Report – Minneapolis Park & Recreation Board Page 29-1

Figure 29-1. Comparison showing the NWS 30-year “normal” with 2015 temperature and precipitation data.

TWIN CITIES RAIN GAUGE COMPARISON

In order to understand the local spatial pattern of precipitation, monthly NWS rainfall data were compared to the MPRB weather station.

The MPRB operates an automated tipping bucket rain gauge in southwest Minneapolis, located on the roof of the Southside Operations Center at 3800 Bryant Ave. South. The NWS heated rain gauge is located at the Twin Cities airport. The MPRB rain gauge is not heated and cannot measure snowmelt. Only totals for May through October were calculated with these instruments. The monthly precipitation differences between the MPRB and NWS can be seen in Table 29-2.

2015 Water Resources Report – Minneapolis Park & Recreation Board Page 29-2

Table 29-2. Monthly totals for the 2015 growing season (May-October) recorded at the NWS, and MPRB rain gages. NWS MPRB Month (inches) (inches) Difference May 3.55 4.01 0.46 June 4.40 3.99 0.41 July 7.32 6.36 0.96 August 2.99 2.58 0.41 September 4.65 3.04 1.61 October 2.61 2.57 0.04

Totals 25.52 22.55 2.97

2015 Water Resources Report – Minneapolis Park & Recreation Board Page 29-3

30. WATER QUALITY EDUCATION

ACTIVITIES

In 2015, Minneapolis Park & Recreation Board (MPRB) staff provided water quality education programs throughout the City. Environmental Management naturalist staff participated in 58 Minneapolis community festivals, neighborhood events, as well as concerts and movies (List 30-1). Hands-on water quality educational displays focused on neighborhood watersheds and how human activities impact local water bodies. Education staff utilized portable mini-golf, an aerial photo floor graphic of the city and its watersheds, and other hands learning activities.

List 30‐1: Neighborhood water quality education event sites. Some sites had multiple events. . Armatage . Bottineau . Bryant Square . Central Park Gym . Creekview . Father Hennepin Bluffs . Fuller . Longfellow . Loring . Luxton . Lyndale . Minnehaha Falls . Martin Luther King . Nicollet Island . Painter . Pershing . Powderhorn . Sibley . Victory Memorial Parkway . Webber . Windom North East . Windom South . Wirth Park

2015 Water Resources Report – Minneapolis Park & Recreation Board Page 30-1

CANINES FOR CLEAN WATER

More than 100,000 dogs reside in the City of Minneapolis. They generate an estimated 41,000 pounds of solid waste each day. A water quality education program targeting dog owners was initiated in 2009 called Canines for Clean Water, and we continue to build on this work. In 2015, the Canines for Clean Water campaign continued to focus on Public Service Announcements (PSAs) shown at the Riverview Theatre, located near the Mississippi River and Lakes Nokomis and Hiawatha. The PSAs focus on two main actions: getting pet owners to pick up after the dogs and encouraging all property owners to stop or reduce their use of salt or chlorides. The PSAs had a simple message with images of the Mississippi River, Lake Nokomis, and Minnehaha Creek. The summer and fall message was to Protect the River, Protect the Lake, Protect the Creek: Grab a Bag and Scoop the Poop. For winter, the images featured winter scenes of the Mississippi River, Lake Nokomis, and dogs frolicking in the snow. The message here was to Protect the River, Protect the Lakes, Protect the Paws: Shovel, Don’t Salt. The word chloride was not used in the PSA because more people understood ice melt as salt. However, detailed information about chlorides, their impacts, best practices for distribution was found on the Minneapolis Park & Recreation Board website www.minneapolisparks.org/dogs. The same was true for information about the impact of dog poop on water quality.

2015 Water Resources Report – Minneapolis Park & Recreation Board Page 30-2

THE MISSISSIPPI RIVER GREEN TEAM

The Mississippi River Green Team (Green Team) is a conservation-based teen crew engaged in daily hands-on environmental work throughout the summer. There are two crews of ten youth each, which work mostly in the natural areas of the Minneapolis park system, and also within the watershed of the Mississippi River. Typical work days include invasive species removal, weed wrenching, planting, watering, mulching, and citizen science work. As part of weekly education days and exposure to green career paths, this year’s crews worked and learned alongside National Park Service Rangers, Minneapolis Park & Recreation Board gardeners, Three Rivers Park District naturalists, Minnesota Conservation Corps members, and a public artist who celebrates quaking bogs. The team members also toured the City of Minneapolis water treatment plant, met scientists at the St. Anthony Falls Laboratory, and explored the University of Minnesota Monarch Lab.

In 2015, the Green Team continued to serve as citizen scientists for the Minnesota Dragonfly Society, formerly known as the Minnesota Odonata Survey Project. Each week the teens caught and identified dragonflies at North Mississippi Regional Park. The crew also surveyed Heritage Park. Dragonflies are an indicator species for assessing habitat and water quality in wetlands, riparian forests, and lakeshore habitats. You can read more about the survey work here: http://www.mndragonfly.org

Other summer work sites included Lake Nokomis, Mill Ruins Park, B F Nelson Park, Heritage Park and Sumner Field, Audubon Park, JD Rivers’ Children’s Garden, Lake Harriet, Minnehaha Park, and Powderhorn Park. The Green Team also worked with staff from Wetland Habitat Restorations, Inc. at several stormwater holding ponds owned by the City of Minneapolis including Camden Central Pond, Central Avenue Pond at Columbia Golf Course, Columbus Ave pond at 37th Street, Heritage Park, and the Park Avenue ponds. The teens removed invasive species and weed trees, picked up trash, and mulched trees and shrub beds. The Mississippi River Green Team is made possible through a partnership between the Minneapolis Park & Recreation Board and the Mississippi Watershed Management Organization, with additional funding through the City of Minneapolis STEP-UP Youth Employment Program.

2015 Water Resources Report – Minneapolis Park & Recreation Board Page 30-3 LAKE CALHOUN

A new moveable water quality education exhibit was deployed at Lake Calhoun near Tin Fish, a very popular lakeside restaurant. The spinning cubes (see image) provides information about watersheds, stormwater runoff, and actions people can take to positively impact water quality. This location was chosen because of the consistent captive audience of people standing in line waiting to order food. Intermittent staff observations throughout the season confirmed that many of the people waiting in line interacted with the cubes.

GREENING TEEN TEAMWORKS

Teen Teamworks is a summer youth employment program managed by the Minneapolis Park & Recreation Board for 30+ years. Teen Teamworks hires and trains 250 to 300 youth each summer to assist in park maintenance work for 8 to 10 weeks depending on available funding. Two MPRB education staff are assigned to work with the site supervisors and teen crews to provide weekly instruction about storm water runoff, water quality, and actions that should be taken to help keep our lakes, creeks, and river healthy. These site-based crews are charged with keeping the park’s storm drains clear and curb lines picked up, and at parks with waterbodies, the crews remove debris from outlets and tidy up shorelines. Crews are required to create a project that demonstrates what they’ve learned about water quality; these projects have included posters, small exhibits, photo collages, short videos, and even a song. As part of the program participants must complete a pre and post knowledge test. Results show that teens and supervisors increase their knowledge and understanding of water quality, watersheds, runoff, and positive actions that benefit our lakes, creeks, and river. The program is funded by the Mississippi Watershed Management Organization.

RECONNAISSANCE WORK FOR 2016 EDUCATION EFFORTS

During 2015, water quality education staff met with managers of local hardware stores to determine their interest and willingness to participate in a winter education campaign focused on reducing chloride use. Based on their input, we will design and fabricate floor graphics that show a typical sidewalk panel and the correct amount of salt/de-icer to apply. The floor graphic will be placed in the hardware store aisle that features de-icer and chlorides. Some store managers also agreed that they could direct check-out staff to place an educational sticker on to each bag of chlorides sold. These items will be fabricated in the summer of 2016 for distribution in October.

The MPRB is currently engaged in an extensive Aquatic Invasive Species (AIS) Inspection Program at the public boat launches located at Lakes Calhoun, Harriet, and Nokomis. The boat launches are staffed seven days a week from May 1 to December 1 and all boats entering and leaving the lakes are inspected for AIS. In addition to providing boat inspections, staff also serves as an information source for the park visitors. During 2015 small sandwich boards were placed adjacent to the AIS booth. The boards had hand written information about the lake and how to be a good water steward. Based on

2015 Water Resources Report – Minneapolis Park & Recreation Board Page 30-4 the positive feedback from park visitors, including a lot of “I didn’t know that”, a set of changeable signs have been created with stewardship messages for use in 2016. The sandwich board messages can be changed out daily based on weather, time of year, etc. Annually more than five million people visit the Chain of Lakes and more than one million visit Lake Nokomis.

TRAINING

Two MPRB full time staff completed the introductory and advanced courses for Fostering Sustainable Behavior Community-Based Social Marketing (CBSM) led by Douglas McKenzie-Mohr. To quote from McKenzie-Mohr’s website, “CBSM is an approach to achieving broad sustainable behavior in our communities. It combines the knowledge from psychology and social marketing to leverage community members’ action to change behavior. CBSM is more than education; it is spurring action by a community and for a community”. Community-based social marketing is composed of four steps: uncovering barriers to behaviors and then, based upon this information, selecting which behavior to promote; designing a program to overcome the barriers to the selected behavior; piloting the program; and then evaluating it once it is broadly implemented (McKenzie-Mohr & Smith, 1999). The MPRB’s goal is to utilize CBSM in future water quality education efforts.

2015 Water Resources Report – Minneapolis Park & Recreation Board Page 30-5 EARTH DAY CLEAN UP EVENT

The Earth Day Watershed Clean-up was initiated in 1995 to draw attention to the water quality improvement needs of Minneapolis’ lakes, and the effects that individual actions have on urban water quality. The goals of the Earth Day Clean-Up event are to prevent trash and debris from entering Minneapolis water bodies, and to provide a volunteer experience and environmental education to Minneapolis residents and park users. This annual event occurs in Minneapolis parks and neighborhood areas that are part of the watersheds of Minneapolis water bodies, including the Chain of Lakes, Lake Nokomis, Lake Hiawatha, Powderhorn Lake, Diamond Lake, Shingle Creek, Minnehaha Creek, Bassett Creek, and the Mississippi River.

The annual Minneapolis Earth Day Clean-Up is held at several sites throughout the City of Minneapolis. It is a collaborative effort between the Minneapolis Park & Recreation Board (MPRB) and City of Minneapolis Solid Waste and Recycling. The 2015 event featured 38 sites across Minneapolis with more than 1800 volunteers helping to pick up and beautify the park system. Volunteers collected an impressive 8,480 pounds of garbage, 620 pounds of recycling and 1,460 pounds of metal. In addition Earth Day participants received education in properly sorting recyclables, garbage and organics as well as the opportunity to participate in naturalist led programs or to build their own bird house.

2015 Water Resources Report – Minneapolis Park & Recreation Board Page 30-6 31. QUALITY ASSURANCE ASSESSMENT REPORT

BACKGROUND

Environmental monitoring and management requires the collection of highly reliable data. Data accepted for inclusion in a database must be of known quality and must meet established criteria. A Quality Assurance Program is a defined protocol for sample collection, handling, and analysis to ensure that the quality of the data collected is quantified and tracked. Quality Assurance consists of two components (Standard Methods, 2005):

 Quality Assessment (QA) Periodic evaluations of laboratory performance through the submission and analysis of externally provided blanks, standard solutions, duplicates, and split samples.  Quality Control (QC) Documented operator competence, recovery of known additions, and analysis of internally provided reagent blanks, proper equipment calibration, and maintenance of control charts.

DESCRIPTION

This Quality Assurance Project Plan (QAPP) describes the procedures and quality control measures used for water quality monitoring and laboratory analyses completed in 2015 for the Minneapolis Chain of Lakes monitoring, the National Pollutant Discharge Elimination Systems (NPDES) stormwater monitoring, and other studies. The project activities for lake sampling are detailed in the Lake Monitoring Program Overview, Section 1. Stormwater monitoring procedures are explained in the Stormwater Monitoring Program Manual (MPRB, 2001).

QA/QC definitions, as presented by T.A. Dillaha, et al. (1988) and Standard Methods for the Examination of Water and Wastewater (2005), are used in the presentation of the information in this document.

 Precision is a measure of the degree of agreement between independent measurements of some property. Precision is concerned with the closeness of the results and is usually expressed in terms of the standard deviation of the data for duplicate or replicate analyses. Precision is a measure of how close the results are together with respect to each other not how close they are to a “true value.”

 Accuracy is a measure of the degree of agreement of a measured value with an accepted reference or true value. It is usually expressed in terms of percent recovery of the expected value (standard solution) and is an expression of the amount of bias in the data. Accuracy is a measure of how close the results are to a known “true value.”

 Representativeness is a measure of the degree to which data accurately and precisely represent the characteristics of the population which is being monitored.

2015 Water Resources Report – Minneapolis Park & Recreation Board Page 31-1  Completeness is a measure of the amount of valid data obtained from a measurement system compared to the amount expected to be obtained under correct normal conditions. For example, a data set for a lake will not be complete if the laboratory did not analyze all expected parameters. Completeness is usually expressed as a percent of the “true value.”

 Comparability expresses the confidence with which one data set, measuring system, or piece of equipment can be compared with another. Data can be considered comparable if they are similar to those reported by others in the literature, data from previous years, and if the analysis procedures produce results similar to those reported by other laboratories for split samples.

The frequencies of quality assessment and quality control activities are set forth to ensure the validity of the database is listed in Table 31-1. The QA/QC plan follows the recommendations of Standard Methods for the Examination of Water and Wastewater (2005).

Table 31-1. Summary and frequency of QA/QC activities.

Sample type Description Function Frequency Reagent-grade de-ionized water Estimating background values End of sampling Equipment Blank subject to sample collection, due to sample collection, season processing and analysis processing and analysis Reagent-grade de-ionized water Estimating background values Bottle Blank/Field Blank subject to sample processing and due to sample processing and Each sampling trip analysis analysis; carried in the field Duplicate of lake sampling Estimating lab batch and Field Duplicate Each sampling trip procedures sampling procedure precision Blind QA/QC Audit Synthetic sample to mimic a Estimating overall batch Once/Month Standard natural sample precision and lab bias Laboratory Calibration Standard solution from a source Calibrate the instrument before One/lab batch (10% Standard other than the control standard samples are analyzed of samples)

Laboratory Calibration Identifying signal drift and One/lab batch (10% Reagent-grade de-ionized water Blank contamination of samples of samples) Laboratory Reagent Reagent-grade de-ionized water Identifying contamination of One/lab batch (10% Blank plus reagents reagents of samples) Determining accuracy and Laboratory Control Standard solution from a source One/lab batch (10% consistency of instrument Standard other than calibration standard of samples) calibration 2 different lakes, Split of lake sample sent to Split Samples Determining comparability once during sampling different laboratories for analysis season Determining analytical precision 10% of samples (at Laboratory Duplicate Split of sample aliquot within batches least one per batch) Laboratory Matrix Known spike of sample (recovery Determining percent recovery of 10% of samples (at Spike/Matrix Spike of known additions) parameter analyzed least one per batch) Duplicate

2015 Water Resources Report – Minneapolis Park & Recreation Board Page 31-2 OBJECTIVES

The primary objective of this QAPP is to ensure and identify the completeness, representativeness, precision, accuracy, and comparability of the data collected. The following pages summarize these data characteristics for results from both field measurements and parameters as analyzed by Instrumental Research Inc. (IRI) located in Fridley, MN. Metals analysis was performed by Legend Technical Services located in St. Paul, MN.

This program was designed to clearly establish which data were: 1) usable, 2) of questionable usability and needed to be flagged or 3) unusable. Quantitative data quality descriptions have been included to provide data users with background on why certain data were deemed to be questionable or unusable. This enables the data user to apply more or less stringent acceptance limits on defining usability to meet the objectives of their own analyses. Quantitative data quality indicators were calculated for each analysis method individually. In order to estimate quantitative data quality indicators on a method-by-method basis, all samples analyzed using a given method were treated as belonging to the same population (Fairless and Bates, 1989).

The QAPP set forth target frequencies for all QA/QC activities:  Every sampling batch included analysis blanks, standards, and duplicates for each set of samples analyzed.  Ten percent of all samples were run in duplicate.  The fall sampling trip had equipment blanks associated with them.  A bottle field blank was associated with every sampling trip.  One laboratory reagent blank was analyzed for every ten samples run.  Filter blanks were analyzed where appropriate.  A matrix spike was analyzed with every ten samples.

Blind performance evaluation samples of known concentration were submitted monthly to the laboratory by the MPRB for analysis. The performance evaluation samples served as a quality assessment of monthly analytical runs. IRI used the following procedures during each analytical run:  Blanks for water and reagents (one for each) were analyzed for every 10 samples run.  A standard of known concentration was analyzed for each analytical run.  One spike (recovery of known additions) was analyzed for every 10 samples run.  One duplicate sample was analyzed for every 10 samples run, which included duplicate spikes.

Additional quality control measures used in the contract laboratory were as follows:  Control charts were maintained for all routinely measured parameters and analyses were not performed unless control (reference) samples fell within the specified acceptance limits see Table 31- 2.  Experienced individuals trained technicians before they were allowed to conduct analyses by themselves and their supervisors routinely reviewed their performance.

2015 Water Resources Report – Minneapolis Park & Recreation Board Page 31-3 Table 31-2. 2015 IRI analytical laboratory and Legend Technical Services reporting limits, the performance evaluation (PE) percent recovery acceptance limits, and relative percent difference (RPD) allowed with duplicates. NA = Not Applicable.

Legend PE % Rec Duplicate RPD Parameter Abbreviation IRI MDL MDL Limits Limits Alkalinity, Total Alk 2.0 mg/L NA 80-120 ±10% Ammonia, Un-ionized as N NH3 0.500 mg/L NA 80-120 ±10% BOD, 5 Day carbonacious cBOD 1.0 mg/L NA 80-120 ±10% Calcium Ca NA 1.0 mg/L 80-120 ±10% Chloride, Total Cl 2.0 mg/L NA 80-120 ±10% Chlorophyll-a Chl-a 5 µg/L NA NA ±25% Conductivity Cond 10 µmhos/cm NA 80-120 ±25% Copper, Total Cu NA 1.4 µg/L 80-120 ±25% Escherichia coli E. coli 1 MPN per 100ml NA NANA Enterococci Enterococci 1 MPN per 100ml NA NANA Hardness, Total as CaCO3 Hard 2.0 mg/L NA 80-120 ±10% Kjeldahl Nitrogen, Total TKN 0.500 mg/L NA 80-120 ±10% Lead, Total Pb NA 3 µg/L 80-120 ±25% Nitrite+Nitrate, Total as N NOx or NO2NO3 0.030 mg/L NA 80-120 ±10% Nitrogen, Total (persulfate) TN 0.500 mg/L NA 80-120 ±10% pH pH 1.00 Std Units NA 80-120 ±10% Phosphorus, Dissolved TDP 0.010 mg/L NA 80-120 ±10% Phosphorus, Total TP 0.010 mg/L NA 80-120 ±10% Silica, Reactive Si 0.500 mg/L NA NA ±10% Solids, Total Dissolved TDS 2.0 mg/L NA 80-120 NA Solids, Total Suspended TSS 1.0 mg/L NA 80-120 NA Solids, Volatile Suspended VSS 2.0 mg/L NA 80-120 ±10% Soluble Reactive Phosphorus SRP 0.003 mg/L NA 70-130 ±25% Zinc, Total Zn NA 2 µg/L 80-120 ±25%

METHODS

Laboratory results and field data were entered into a spreadsheet. Data were evaluated to determine usability according to the methods below. Data were categorized into one of three levels of usability: fully usable, questionable usability, or unusable. To be “fully usable” the data had to meet all of the data quality criteria: completeness, representativeness, comparability, precision, and accuracy. Data rated as “questionable usability” met all but one of the quality criteria. Unusable data were those that were known to contain significant errors or data that met fewer than four of the data quality criteria.

Completeness: Data sets were deemed to be complete if fewer than 5% of the data were missing or not analyzed appropriately. Representativeness: Data sets were deemed to be representative if samples were collected according to the sampling schedule, and standard collection and handling methods were followed. Monitoring locations, frequencies and methods followed suggested protocol to ensure representativeness (Wedepohl et al., 1990).

Comparability: Data for a given parameter were deemed to be highly comparable if the laboratory split results from all three labs for that parameter had a relative

2015 Water Resources Report – Minneapolis Park & Recreation Board Page 31-4 percent difference of less than 20% and if reported values were consistent with past results. If the relative percent difference between labs for a given parameter was more than 20% but the majority of data reported were within 20% the data set for that parameter was deemed to be moderately comparable. Coefficient of variation (CV) was used as another measure of how close the laboratories were to each other.

Coefficient of Variation (CV) = standard deviation mean

Precision: Data sets were deemed precise if two criteria were met (Standard Methods, 2005): 1. The relative percent difference of results for each pair of duplicate analyses was within acceptance limits for each given parameter. 2. The percent recovery of known standard additions met the established acceptance limits for each parameter.

Percent Recovery (% Rec) = Observed Value X 100% Expected Value

Precision was further quantified by calculating the average range and standard deviation of results for duplicates.

Relative Percent Difference (RPD) = |X - X | 1 2 X 100% (X1 + X2)/2

Where: X1 and X2 are duplicate pair values; sum for all duplicates

Average Range (R) =

Σ | X1 - X2 | n

Where: X1 and X2 are duplicate pair values; sum for all duplicates, and n = number of duplicate pairs

Standard Deviation (estimated)

Accuracy: Data sets were deemed accurate if the percent recovery reported for performance evaluation standards fell within the established acceptance limits for each given

2015 Water Resources Report – Minneapolis Park & Recreation Board Page 31-5 parameter and had been deemed precise (Table 31-2). The percent recovery estimates bias in the data set. Together, bias and precision reflect overall data set accuracy (Standard Methods, 2005). Low bias and high precision translates to high accuracy.

The standard solutions used for performance evaluation samples were manufactured by Environmental Resource Associates (ERA) located in Arvada, Colorado and diluted by MPRB staff to achieve the desired concentrations. ERA provided performance acceptance limits for the recovery of each analyte. These performance limits defined acceptable analytical results given the limitations of the United States Environmental Protection Agency (US EPA) approved and Standard Methods methodologies (US EPA Reports, 1980, 1985). The acceptance limits were based on data generated by laboratories in ERA's InterLab program and data from the US EPA and closely approximated the 95% confidence interval. If a laboratory failed a blind monthly performance standard all of the monthly data for that parameter were flagged as questionable. Laboratories were allowed ± 20% recovery for all parameters except soluble reactive phosphorus and total dissolved phosphorus data which were allowed ± 30% recovery due to the low phosphorus concentrations.

The contract laboratories provided minimum detection limits (MDL) and reporting limits (RL). The IRI laboratory calculated the MDL based upon documented performance studies and the RL are two to five times the MDL. Table 31-2 lists the reporting limits for analyses as provided by IRI.

RESULTS AND DISCUSSION

If the “blind” monthly performance standard failed to achieve the required percent recovery (±20%) and the error was greater than two times the reporting limit, the entire month’s data were flagged by underlining it. There were a total of four data points flagged in 2015. These include the February Cu, March TDP, August TSS, and September Conductivity.

Completeness The data collected in 2015 was deemed to be complete. Missing data and improper analyses accounted for less than 1% of the samples collected. A minimum of 10% of the final data were checked by hand against the raw data sent by the laboratories to ensure there were no errors entering or transferring the data.

Representativeness The 2015 lakes data were deemed to be representative of actual in-lake conditions. Samples were collected over the deepest point of each lake to create a profile at appropriate meter depths. The duration of monitoring, sampling frequency, site location, and depth intervals sampled met or exceeded the recommendations to collect representative data and to account for seasonal changes and natural variability (Wedepohl et al., 1990). Sample collection and handling followed established protocol for monitoring water quality as detailed in Standard Methods for the Examination of Water and Wastewater (2005). NPDES stormwater samples were collected in accordance with the Stormwater Monitoring Program Manual (MPRB, 2001).

Comparability

Between Years The 2015 lakes data were deemed to be comparable to previous years’ data. In reviewing box and whisker plots of total phosphorus, Secchi transparency, and chlorophyll-a data, reported values appeared to be consistent with values reported at the same times during the 2012 - 2014 monitoring

2015 Water Resources Report – Minneapolis Park & Recreation Board Page 31-6 seasons. The 2015 monitoring season was roughly comparable to the 2014 monitoring season. Stormwater data for 2015 appeared to be very comparable to other stormwater data, however, it should be noted that stormwater concentrations are highly variable.

Between Laboratories To determine data comparability between laboratories lake samples were split in the field and shared with IRI, Minnehaha Creek Watershed District (MCWD), and Three Rivers Park District (TRPD). MCWD used RMB Environmental Laboratories, Detroit Lakes, MN as their laboratory and TRPD uses their own in-house laboratory. The 2015 lake split data set were deemed to be generally comparable to data analyzed by TRPD and MCWD, but there were significant issues with Chl-a and Cl, as seen in Table 31-3. The MPRB shared “round-robin” format split samples with the participating laboratories from one sampling event on July 20th, 2015. The results from all agency split samples are summarized in Table 31-3 and in Figures 31-1 through 31-5.

Data for a given parameter were deemed to be highly comparable if the laboratory split results for that parameter from all the laboratories had a coefficient of variation (CV) less than 20% and if reported values were consistent with past results. Generally if the CV between laboratories for a given parameter was more than 20% then the data set for that parameter was deemed to be moderately comparable. If a majority of the parameters tested for the data set had a laboratory outlier the comparability was deemed low. Care must be taken when interpreting these data at very low levels or near reporting limits. For example, the CV between 1 and 2 µg/L is 47%, but the CV between 10 and 11 µg/L is 7%. Both have a difference of 1 µg/L. In Table 31-3 the SRP values reported below reporting limits did not have CV’s calculated if more than two laboratories were below reporting limits.

2015 Water Resources Report – Minneapolis Park & Recreation Board Page 31-7 Table 31-3. Summary of 2015 split sample results reported by IRI, MCWD, and TRPD.

ID Parameter Units Depth Lake MPRB MCWD TRPD CV 1 Chla mg/M3 0-2 Harriet 2 5 7 61% 2 Chla mg/M3 0-2 LHL01 T 29 56 60 34% 3 Chla mg/M3 0-2 MED 0-2 14 34 36 43% 4 TP mg/l 0-2 Harriet 0.023 0.021 0.021 6% 5 TP mg/l 20 Harriet 0.303 0.326 0.296 5% 6 TP mg/l 0-2 LHL01 T 0.090 0.140 0.117 21% 7 TP mg/l 8 LHL01B 3.46 1.64 1.45 51% 8 TP mg/l 0-2 MED 0-2 0.064 0.051 0.052 13% 9 TP mg/l 6 MED 6 0.060 0.056 0.041 19% 10 TP mg/l 12 MED 12 0.687 0.703 0.658 3% 11 TP mg/l Standard REB 0.130 0.003 0.126 84% 12 SRP mg/l 0-2 Harriet 0.003 0.003 0.006 43% 13 SRP mg/l 20 Harriet 0.294 0.313 0.290 4% 14 SRP mg/l 0-2 LHL01 T 0.024 0.027 0.031 14% 15 SRP mg/l 8 LHL01B 1.33 1.17 1.13 9% 16 SRP mg/l 0-2 MED 0-2 0.005 0.003 0.009 54% 17 SRP mg/l 6 MED 6 0.010 0.013 0.013 15% 18 SRP mg/l 12 MED 12 0.439 0.465 0.397 8% 19 SRP mg/l Standard REB 0.074 0.076 0.074 1% 20 TN mg/l 0-2 Harriet 0.500 0.436 0.500 8% 21 TN mg/l 0-2 LHL01 T 1.43 1.43 1.70 10% 22 TN mg/l 0-2 MED 0-2 1.84 0.794 0.840 51% 23 TN mg/L Standard REB 2.94 0.302 2.90 74% 24 Cl mg/l 0-2 Harriet 110 123 120 6% 25 Cl mg/l 20 Harriet 113 132 125 8% 26 Cl mg/l 0-2 LHL01 T 41 36 35 9% 27 Cl mg/l 8 LHL01B 36 35 34 3% 28 Cl mg/l 0-2 MED 0-2 187 150 142 15% 29 Cl mg/l 12 MED 12 199 155 140 19% Notes: CV = Coefficient of Variation. Underlined data are less than values. nc = not calculated. NS = no sample.

The comparability of the inter-laboratory split sample within each of the parameters differed considerably. Table 31-4 details the variability within parameters and lists the determined level of comparability for each. The comparability between years was determined by comparing 2015 values to previous year’s data. The 2015 data set were somewhat comparable to previous years. The final CV calculated for SRP should not be used if many are below or near detection limit values.

2015 Water Resources Report – Minneapolis Park & Recreation Board Page 31-8 Table 31-4. 2015 comparability of parameters analyzed as a part of the inter-laboratory split sample program and compared to previous years’ data. Values listed are the range and mean for the coefficient of variation between labs.

Coefficient of Variation Comparability Parameter 2015 Range 2015 Mean % Between labs Between years Chl-a 34%-61% 46% Low Low TP 3%-51% 25% Moderate Moderate SRP 1%-54% 18% Moderate Moderate TN 8%-51% 36% Low Low Cl 3%-19% 10% Moderate High

The split samples for chlorophyll-a had low comparable as seen in Figure 31-1. All laboratories used a spectrophotometer. In 2015 all chlorophyll-a lake data points had suspect samples. The outliers were sample ID number 1, 2, and 3. IRI will investigate why they are consistently low. Since there is no chlorophyll-a standard, the MRPB should seriously consider using HPLC to determine the “true” chlorophyll-a concentration of each sample. Chlorophyll-a concentrations can be extremely variable due to inherent sampling limitations and plankton patchiness as well as the difficulty in laboratory grinding and analysis. The average CV for chlorophyll-a was 46%.

Figure 31-1. Plot of chlorophyll-a split sample results reported for 2015. See Table 31-3 to reference ID numbers with sample descriptions and results.

2015 Water Resources Report – Minneapolis Park & Recreation Board Page 31-9 Total phosphorus splits were moderately comparable as seen in Figure 31-2. Most of the samples were moderate to lower level concentrations but none were at detection limit. The high outlier was sample ID number 7, analyzed by the MPRB. Phosphorus is an important and limiting aquatic nutrient and accuracy for this element is critical. The average CV for TP was 25%.

Figure 31-2. Scatter plot of total TP split sample results reported for 2015. See Table 31-3 to reference ID numbers with descriptions and results.

2015 Water Resources Report – Minneapolis Park & Recreation Board Page 31-10

Two concentrations of the submitted SRP split samples were near lab reporting limits or near detection levels as seen in Figure 31-3. There were no significant outliers. IRI and MCWD (RMB laboratory) had a reporting limit of 0.003 mg/L, while TRPD has a reporting limit of 0.006 mg/L. The split SRP data must be deemed of questionable comparability especially at concentrations below 0.006 mg/L. Users of these data must decide if this loss of resolution at low concentrations is of significant concern for any given data application. The average CV for SRP was 18%.

Figure 31-3. Scatter plot of SRP split sample results reported for 2015. See Table 31-3 to reference sample ID numbers with descriptions and results.

2015 Water Resources Report – Minneapolis Park & Recreation Board Page 31-11

Total nitrogen splits were completed by IRI, TRPD and MCWD as seen in Figure 31-4. The significant outliers for TN were sample ID numbers 22 and 23. Sample number 22 the MPRB was the outlier and sample number 23 MCWD was the outlier. TRPD and IRI perform a persulfate digestion and MCWD (RMB laboratory) performs a sum of the nitrogen species TKN and NO3NO2. The average CV for TN was 36%.

Figure 31-4. Scatter plot of TN split sample results reported for 2015. See Table 31-3 to reference ID numbers with descriptions and results.

2015 Water Resources Report – Minneapolis Park & Recreation Board Page 31-12

Chloride splits were completed by IRI, TRPD and MCWD as seen in Figure 31-5. Sample ID numbers 28 and 29 were outliers and were both analyzed by the MPRB. Chloride is an extremely stable test and there is generally little variability between laboratories. The average CV for chloride was 10%.

Figure 31-5. Scatter plot of Cl split sample results reported for 2015. See Table 31-3 to reference ID numbers with descriptions and results.

The split data show the MPRB laboratory (IRI) as a consistent and significant outlier in the Chl-a split samples. The MPRB laboratory also had two chloride outliers. This is also of concern since chloride is a very stable test and easy to replicate. With the exception of Chl-a, the data sets appear moderately to very comparable since all parameters had some outliers. Depending on the parameter, 2015 saw both more and less scatter among the splits than in 2014.

Precision The first criterion used for assessing data precision was the relative percent difference (RPD) between duplicates. For reporting and calculation purposes, the average of duplicate samples was used.

Field Duplicates Field duplicates test the reproducibility of field methods and also lake uniformity. Table 31-5 summarizes the results from field duplicate samples in 2015. Significant differences between duplicates was defined as having a RPD greater than 20%. The goal is to have the average RPD for parameters to be 10% or less. When values are near the reporting limit the RPD calculations are skewed but most times the data are considered acceptable.

The difference in some samples may also be the result of lake or pond sediment being disturbed by a boat anchor, water sampling device such as the Kemmerer sampler, or particles in the epilimnion.

2015 Water Resources Report – Minneapolis Park & Recreation Board Page 31-13 Further investigation should look into the cause(s). Low values, for example, of 0.003 and 0.004 with a RPD of 29% should not be considered a true duplicate failure but rather a statistical anomaly.

Table 31-5. 2015 summary of field duplicate sample results and acceptability for IRI Laboratory.

Average Relative Std. Dev. Parameter Units % Difference Average Range (estimated) Acceptable Chl‐a µg/L 6.88 1.20 1.06 Yes Silica mg/L 1.91 0.075 0.066 Yes TP mg/L 3.43 0.004 0.003 Yes SRP mg/L 4.97 0.004 0.003 Yes TKN mg/L 2.44 0.028 0.025 Yes TN mg/L 6.24 0.069 0.062 Yes

NO2NO3 mg/L 0.72 0.015 0.014 Yes Alk mg/L 0.000 0.000 0.000 Yes Hard mg/L 1.33 2.00 1.77 Yes Cl mg/L 1.67 2.57 2.28 Yes

Lab Duplicates IRI reported all internal QA/QC results to the MPRB. The reported RPD values for duplicate analyses were within acceptance limits. All duplicate analyses were deemed acceptable.

Performance Evaluation Samples The second criterion for assessing data precision was percent recovery of performance evaluation samples. Performance evaluation standards were purchased from ERA. MPRB water quality staff used prepared standards mixed to concentrations similar to those being measured in the field for submission to the contract laboratory. The “rule of sensibility” was used to evaluate the data and whether to flag it or not. Table 31-6 and Figures 31-6 through 31-11 summarize the performance evaluation sample results for each parameter. Of the performance parameters tested only four fell outside the recovery limits. Four data points (parameters) were flagged in 2015, the February Cu, March TDP, August TSS, and September Conductivity. All other performance evaluation samples fell within acceptance limits.

2015 Water Resources Report – Minneapolis Park & Recreation Board Page 31-14

Table 31-6. Performance evaluation samples analyzed by IRI in 2015. Results in red are outside acceptance limits.

Sample ID Parameter Date Calc. Value IRI Value % Recovery 1 Alk 2/12/2015 32 31 97% 2 Alk 3/18/2015 32 31 97% 3 Alk 4/15/2015 32 30 94% 4 Alk 5/7/2015 32 30 94% 5 Alk 6/5/2015 91 86 94% 6 Alk 7/7/2015 141 131 93% 7 Alk 8/4/2015 83 78 94% 8 Alk 9/11/2015 36 33 93% 9 Alk 10/30/2015 105 104 99% 10 BOD5C 2/12/2015 8 8 102% 11 BOD5C 3/18/2015 8 8 104% 12 BOD5C 4/15/2015 8 8 102% 13 BOD5C 5/7/2015 7 8 108% 14 BOD5C 6/5/2015 7 8 110% 15 BOD5C 7/7/2015 7 8 110% 16 BOD5C 8/4/2015 7 7 91% 17 BOD5C 9/11/2015 7 7 93% 18 BOD5C 10/30/2015 7 8 106% 19 Cl 2/12/2015 50 48 97% 20 Cl 3/18/2015 50 52 105% 21 Cl 4/15/2015 50 49 99% 22 Cl 5/7/2015 50 53 107% 23 Cl 6/5/2015 80 79 99% 24 Cl 7/7/2015 39 43 110% 25 Cl 8/4/2015 77 79 102% 26 Cl 9/11/2015 48 50 103% 27 Cl 10/30/2015 52 53 101% 28 Conductivity 2/12/2015 329 359 109% 29 Conductivity 3/18/2015 329 336 102% 30 Conductivity 4/15/2015 329 336 102% 31 Conductivity 5/7/2015 329 329 100% 32 Conductivity 6/5/2015 463 457 99% 33 Conductivity 7/7/2015 402 437 109% 34 Conductivity 8/4/2015 459 462 101% 35 Conductivity 9/11/2015 227 293 129% 36 Conductivity 10/30/2015 461 486 105% 37 Cu 2/12/2015 330 260 79% 38 Cu 3/18/2015 330 310 94% 39 Cu 4/15/2015 330 340 103% 40 Cu 5/7/2015 220 230 105% 41 Cu 6/5/2015 220 230 105% 42 Cu 7/7/2015 220 240 109% 43 Cu 8/4/2015 220 220 100% 44 Cu 9/11/2015 220 230 105% 45 Cu 10/30/2015 220 220 100%

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Table 31-6. (continued) Performance evaluation samples analyzed by IRI in 2015. Results in red are outside acceptance limits.

Sample ID Parame te r Date Calc. Value IRI Value % Re cove ry 46 Ecoli -Quarterly 4/15/2015 121 (45-321) 228 100% 47 Ecoli -Quarterly 4/15/2015 <1 <1 100% 48 Ecoli -Quarterly 8/4/2015 267 (133-535) 225 100% 49 Ecoli -Quarterly 8/4/2015 <1 <1 100% 50 Ecoli -Quarterly 10/30/2015 1200 (607-2400) 1203 100% 51 Ecoli -Quarterly 10/30/2015 <1 <1 100% 52 Enterococci 8/4/2015 333 (142-781) 365 100% 53 Enterococci 8/4/2015 <1 <1 100% 54 Fe 7/7/2015 362 390 108% 55 Fe 8/4/2015 362 360 99% 56 Fe 10/30/2015 362 380 105% 57 NH3 2/12/2015 0.484 0.535 111% 58 NH3 3/18/2015 0.484 0.513 106% 59 NH3 4/15/2015 0.484 0.563 116% 60 NH3 5/7/2015 3.48 3.44 99% 61 NH3 6/5/2015 3.48 3.18 91% 62 NH3 7/7/2015 3.48 3.48 100% 63 NH3 8/4/2015 3.48 3.51 101% 64 NH3 9/11/2015 3.58 3.40 95% 65 NH3 10/30/2015 3.48 3.46 99% 66 Nox 2/12/2015 0.970 1.07 110% 67 Nox 3/18/2015 0.970 1.08 111% 68 Nox 4/15/2015 0.970 0.930 96% 69 Nox 5/7/2015 3.58 3.25 91% 70 Nox 6/5/2015 3.58 3.42 96% 71 Nox 7/7/2015 3.58 3.67 103% 72 Nox 8/4/2015 3.58 3.56 99% 73 Nox 9/11/2015 3.58 4.24 118% 74 Nox 10/30/2015 3.58 3.56 99% 75 Ortho-P 7/7/2015 0.006 0.007 111% 76 Ortho-P 2/12/2015 0.017 0.016 94% 77 Ortho-P 3/18/2015 0.017 0.019 112% 78 Ortho-P 4/15/2015 0.017 0.017 100% 79 Ortho-P 5/7/2015 0.006 0.008 127% 80 Ortho-P 6/5/2015 0.006 0.007 111% 81 Ortho-P 8/4/2015 0.006 0.007 111% 82 Ortho-P 9/11/2015 0.006 0.007 111% 83 Ortho-P 10/30/2015 0.006 0.008 127% 84 Pb 2/12/2015 7 6 83% 85 Pb 3/18/2015 7 6 87% 86 Pb 4/15/2015 7 7 107% 87 Pb 5/7/2015 15 14 96% 88 Pb 6/5/2015 15 13 89% 89 Pb 7/7/2015 16 17 109% 90 Pb 8/4/2015 15 14 96% 91 Pb 9/11/2015 15 15 103% 92 Pb 10/30/2015 15 16 110%

2015 Water Resources Report – Minneapolis Park & Recreation Board Page 31-16 Table 31-6. (continued) Performance evaluation samples analyzed by IRI in 2015. Results in red are outside acceptance limits.

Sample ID Parame te r Date Calc. Value IRI Value % Re cove ry 93 SO4 2/12/2015 34 31 94% 94 SO4 3/18/2015 33.5 31.6 94% 95 SO4 4/15/2015 33.5 32.0 96% 96 SO4 5/7/2015 33.5 31.9 95% 97 SO4 6/5/2015 18.1 15.2 84% 98 SO4 7/7/2015 17.6 14.9 85% 99 SO4 8/4/2015 17.6 14.4 82% 100 SO4 9/11/2015 17.5 15.5 89% 101 SO4 10/30/2015 37.6 34.8 93% 102 SRP 2/12/2015 0.017 0.016 94% 103 SRP 3/18/2015 0.017 0.019 112% 104 SRP 4/15/2015 0.017 0.017 100% 105 SRP 5/7/2015 0.006 0.008 127% 106 SRP 6/5/2015 0.006 0.007 111% 107 SRP 7/7/2015 0.006 0.008 127% 108 SRP 8/4/2015 0.006 0.008 127% 109 SRP 9/11/2015 0.006 0.007 111% 110 SRP 10/30/2015 0.006 0.008 127% 111 TDP 2/12/2015 0.017 0.018 106% 112 TDP 3/18/2015 0.017 0.022 130% 113 TDP 4/15/2015 0.017 0.018 106% 114 TDP 5/7/2015 0.006 0.007 111% 115 TDP 6/5/2015 0.006 0.007 111% 116 TDP 7/7/2015 0.006 0.006 96% 117 TDP 8/4/2015 0.006 0.006 96% 118 TDP 9/11/2015 0.006 0.006 96% 119 TDP 10/30/2015 0.006 0.007 111% 120 TDS 2/12/2015 223 224 100% 121 TDS 3/18/2015 223 234 105% 122 TDS 4/15/2015 223 221 99% 123 TDS 5/7/2015 223 221 99% 124 TDS 6/5/2015 383 368 96% 125 TDS 7/7/2015 414 433 105% 126 TDS 8/4/2015 367 325 89% 127 TDS 9/11/2015 192 186 97% 128 TDS 10/30/2015 412 393 95% 129 TKN 2/12/2015 1.24 1.23 99% 130 TKN 3/18/2015 1.24 1.29 104% 131 TKN 4/15/2015 1.24 1.21 98% 132 TKN 5/7/2015 2.46 2.46 100% 133 TKN 6/5/2015 2.46 2.46 100% 134 TKN 7/7/2015 2.46 2.38 97% 135 TKN 8/4/2015 2.46 2.21 90% 136 TKN 9/11/2015 2.46 2.75 112% 137 TKN 10/30/2015 2.46 2.45 100%

2015 Water Resources Report – Minneapolis Park & Recreation Board Page 31-17 Table 31-6. (continued) Performance evaluation samples analyzed by IRI in 2015. Results in red are outside acceptance limits.

Sample ID Parameter Date Calc. Value IRI Value % Recovery 138 TN 2/12/2015 1.24 1.44 116% 139 TN 3/18/2015 1.24 1.35 109% 140 TN 4/15/2015 1.24 1.31 106% 141 TN 5/7/2015 2.46 2.55 104% 142 TN 6/5/2015 2.46 2.77 113% 143 TN 7/7/2015 2.46 2.47 100% 144 TN 8/4/2015 2.46 2.55 104% 145 TN 9/11/2015 2.46 2.75 112% 146 TN 10/30/2015 2.46 2.55 104% 147 Total Hardness 2/12/2015 137 144 105% 148 Total Hardness 3/18/2015 137 128 93% 149 Total Hardness 4/15/2015 115 116 101% 150 Total Hardness 5/7/2015 137 128 93% 151 Total Hardness 6/5/2015 279 256 92% 152 Total Hardness 7/7/2015 362 344 95% 153 Total Hardness 8/4/2015 141 151 107% 154 Total Hardness 9/11/2015 221 200 90% 155 Total Hardness 10/30/2015 168 164 98% 156 TP01 2/12/2015 0.316 0.313 99% 157 TP01 3/18/2015 0.126 0.123 97% 158 TP01 4/15/2015 0.126 0.125 99% 159 TP01 5/7/2015 0.073 0.073 101% 160 TP01 6/5/2015 0.015 0.014 97% 161 TP01 7/7/2015 0.034 0.036 107% 162 TP01 8/4/2015 0.036 0.037 102% 163 TP01 9/11/2015 0.036 0.034 94% 164 TP01 10/30/2015 0.036 0.038 105% 165 TP02 2/12/2015 1.26 1.26 100% 166 TP02 3/18/2015 1.26 1.26 100% 167 TP02 4/15/2015 1.26 1.28 101% 168 TP02 5/7/2015 0.726 0.730 101% 169 TP02 6/5/2015 0.726 0.735 101% 170 TP02 7/7/2015 0.726 0.755 104% 171 TP02 8/4/2015 0.726 0.728 100% 172 TP02 9/11/2015 0.726 0.716 99% 173 TP02 10/30/2015 0.726 0.702 97% 174 TSS 2/12/2015 55 49 89% 175 TSS 3/18/2015 55 53 95% 176 TSS 4/15/2015 69 60 87% 177 TSS 5/7/2015 55 53 96% 178 TSS 6/5/2015 63 60 95% 179 TSS 7/7/2015 36 34 94% 180 TSS 8/4/2015 35 46 134% 181 TSS 9/11/2015 42 38 90% 182 TSS 10/30/2015 76 69 90%

2015 Water Resources Report – Minneapolis Park & Recreation Board Page 31-18 Table 31-6. (continued) Performance evaluation samples analyzed by IRI in 2015. Results in red are outside acceptance limits.

Sample ID Parameter Date Calc. Value IRI Value % Recovery 183 Zn 2/12/2015 292 300 103% 184 Zn 3/18/2015 291 270 93% 185 Zn 4/15/2015 292 310 106% 186 Zn 5/7/2015 255 280 110% 187 Zn 6/5/2015 255 290 114% 188 Zn 7/7/2015 255 280 110% 189 Zn 8/4/2015 255 260 102% 190 Zn 9/11/2015 255 280 110% 191 Zn 10/30/2015 255 280 110% 192 Ca, Calcium 4/15/2015 16 16 102% 193 K Potassium 4/15/2015 35 33 95% 194 Mg, Manganese 4/15/2015 18 19 104%

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Figure 31-6. Scatter plot of reported percent recoveries for performance evaluation samples in 2015. See Table 31-6 to reference ID numbers with descriptions and results.

Figure 31-7. Scatter plot of reported percent recoveries for performance evaluation samples in 2015. See Table 31-6 to reference ID numbers with descriptions and results.

2015 Water Resources Report – Minneapolis Park & Recreation Board Page 31-20

Figure 31-8. Scatter plot of reported percent recoveries for performance evaluation samples in 2015. See Table 31-6 to reference ID numbers with descriptions and results.

Figure 31-9. Scatter plot of reported percent recoveries for performance evaluation samples in 2015. See Table 31-6 to reference ID numbers with descriptions and results.

2015 Water Resources Report – Minneapolis Park & Recreation Board Page 31-21 Most of the performance evaluation standards were acceptable for all months. Alkalinity, chloride, hardness, pH, TDS, and TSS are pre-made and are the only standards that do not require dilution. The remaining standards were diluted before they were submitted to the lab.

All E. coli standards were acceptable. The performance acceptance limits for E coli and Enterococci supplied by ERA are much wider than for the other parameters, (+/- 50%). The coliform and Enterococci standards are shipped directly to the (MPRB laboratory) IRI from ERA.

SRP and TDP performance evaluation samples were mixed to low concentrations approximately 10- 20 times the minimum detection limit. Standard Methods (2005) recommends that performance evaluation samples be mixed to a minimum concentration of 5 times the minimum detection limit. Because of the low concentrations the acceptance limit for SRP and TDP were widened from the recommended 80-120% range to 70-130% recovery. All SRP samples were acceptable in both the 70-130% and 80-120% range.

The February Cu, March TDP, August TSS, and September Conductivity samples were flagged as failing for that month.

Analysis of Equipment Blanks and Field Blanks Equipment blanks were run for both lake water and stormwater sampling equipment. Results from lake and stormwater equipment blanks for 2015 yielded non-detects for all parameters. The 2015 results from the bottle/field blanks which were carried in the field unopened yielded non-detects for all parameters. Reagent blanks run by IRI laboratories during batch analyses resulted in no detectable levels for all parameters analyzed.

Recovery of Known Additions and Internally Supplied Standard Solutions All of the recovery values for spike samples (known additions) reported by IRI were within acceptance limits. All of the reported recoveries for internally supplied standards of known concentration were within acceptance limits.

FINAL ASSESSMENT OF DATA USABILITY

Table 31-7 lists the overall completeness, representativeness, comparability, and precision determined for the 2015 data by parameter. All additional parameters not analyzed by IRI and collected in the field (dissolved oxygen, temperature, conductivity, pH, and Secchi transparency) were deemed to be fully usable. These measurements followed standard methods and protocols for collection and daily equipment calibration.

The 2015 data designated as “questionable usability” may still meet the data quality needs of some analyses. Users of these data should assess if the data quality indicators discussed in this document meet their needs. Much of the data designated as questionably usable are categorized as such because of a missed performance evaluation standard or split samples with low comparability.

The parameters listed on Table 31-7 as questionably usable are only so for the months that they failed monthly performance standards or for split comparability. No parameters in 2015 failed performance standards for every month. When reviewing the monthly performance samples the “rule of sensibility” must be applied and percent recovery must be viewed in relation to the values (low or high), stability of the test and multiple of the reporting limit (2X) used to qualify the data.

2015 Water Resources Report – Minneapolis Park & Recreation Board Page 31-22

Table 31-7. Summary of 2015 data usability by parameter. ‘+’ denotes that acceptance criteria were met, ‘’ denotes that some of the data were of questionable usability, ‘ᴥ’ denotes that data were not within acceptable range.

Completeness Representativeness Precision Comparability Parameter (<5% missing (representative of (lab field dups, (splits, 2015 data) data) natural samples) performance) Alkalinity + + + + Ammonia + + + + BOD 5 day + + + + Conductivity + + +  Chloride + +  + Chlorophyll-a + + ᴥ + Copper + + +  E. coli + + + + Hardness + + + + Lead + + + + Nitrate+Nitrite + + + + Ortho-P + + + + pH + + + + Silica + + + + Soluble Reactive Phosphorus + + + + Sulfate + + + + Total Dissolved Phosphorus + + + + Total Dissolved Solids + + +  Total Kjeldahl Nitrogen + + + + Total Nitrogen + +   Total Phosphorus + + + + Total Suspended Solids + + +  Zinc + + + +

2015 Water Resources Report – Minneapolis Park & Recreation Board Page 31-23 32. ADDITIONAL SOURCES OF WATER QUALITY INFORMATION

Minneapolis Park and Recreation Board

Water Quality Homepage https://www.minneapolisparks.org/park_care__improvements/water_resources 612.230.6400

City of Minneapolis

Storm and Surface Water Management Website http://www.ci.minneapolis.mn.us/stormwater/

Results Minneapolis Lake water quality http://www.ci.minneapolis.mn.us/results/env/waterquality

Watershed Management Organizations

Bassett Creek Watershed Management Commission http://www.bassettcreekwmo.org/

Minnehaha Creek Watershed District http://www.minnehahacreek.org/ 952.471.0590

Mississippi Watershed Management Organization http://www.mwmo.org/ 651-287-0948

Shingle Creek Watershed Management Commission http://www.shinglecreek.org/ 763-553-1144

2015 Water Resources Report – Minneapolis Park & Recreation Board Page 32-1 Hennepin County or Metro Resources

Hennepin County Environmental Services http://www.hennepin.us/residents#environment 612.348.3777

Minnesota Wetland Health Evaluation Project (WHEP) http://www.mnwhep.org/

Metropolitan Council – Environmental Services https://metrocouncil.org/About-Us/What-We-Do/Departments/Environmental-Services.aspx 651.602.1000

State of Minnesota Resources

Minnesota Department of Natural Resources Information on lake surveys, maps, fish stocking, fish advisories and more. http://www.dnr.state.mn.us/lakefind/ 651.296.6157

Aquatic Invasive Species http://www.dnr.state.mn.us/invasives/index_aquatic.html

Minnesota Pollution Control Agency Information on environmental monitoring, clean-up, and more. https://www.pca.state.mn.us/ 651.296.6300

Minnesota Department of Health http://www.health.state.mn.us/

Minnesota Lake Superior Beach Monitoring Program http://www.mnbeaches.org

Minnesota Department of Agriculture – Water & Land http://www.mda.state.mn.us/protecting.aspx 651.297.2200

Minnesota Extension Service http://www.extension.umn.edu/

Minnesota Sea Grant http://www.seagrant.umn.edu

2015 Water Resources Report – Minneapolis Park & Recreation Board Page 32-2 US Federal Government

US Army Corps of Engineers St. Paul District http://www.mvp-wc.usace.army.mil/

US Geological Survey – Minnesota Stream data and links to the national website http://mn.water.usgs.gov/ 763.783.3100

US Geological Survey – Nonindigenous Aquatic Species Information and maps of invasive aquatic plants and animals http://nas.er.usgs.gov/default.aspx

Other Resources

Minnesota Climatology Working Group http://climate.umn.edu/

Ice On/Out Information From Environment Canada https://www.naturewatch.ca/icewatch/

Midwest Invasive Plant Network http://www.mipn.org

Minnesota Invasive Species Advisory Council http://www.mda.state.mn.us/misac/

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US EPA. (1980). Interim guidelines and specifications for preparing quality assurance project plans. QAMS-005/80. Office of Research and Development, Washington, D.C.

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2015 Water Resources Report – Minneapolis Park & Recreation Board Page 33-6 APPENDIX A

This section contains box-and-whisker plots for each of the regularly monitored Minneapolis lakes for the entire period of record. A detailed explanation of box-and-whisker plots can be found in Section 1.

2015 Water Resources Report – Minneapolis Park & Recreation Board Page A-1 Brownie Lake 1991-2014

2015 Water Resources Report – Minneapolis Park & Recreation Board Page A-2 Lake Calhoun 1991-2015

2015 Water Resources Report – Minneapolis Park & Recreation Board Page A-3 Cedar Lake 1992-2015

2015 Water Resources Report – Minneapolis Park & Recreation Board Page A-4 Diamond Lake 1992-2015

2015 Water Resources Report – Minneapolis Park & Recreation Board Page A-5 Grass Lake 2002-2014

2015 Water Resources Report – Minneapolis Park & Recreation Board Page A-6 Lake Harriet 1991-2015

2015 Water Resources Report – Minneapolis Park & Recreation Board Page A-7 Lake Hiawatha 1992-2015

2015 Water Resources Report – Minneapolis Park & Recreation Board Page A-8 Lake of the Isles 1991-2015

2015 Water Resources Report – Minneapolis Park & Recreation Board Page A-9 Loring Pond 1992-2015 Note: Loring was not sampled in 1997.

2015 Water Resources Report – Minneapolis Park & Recreation Board Page A-10 Lake Nokomis 1992-2015

2015 Water Resources Report – Minneapolis Park & Recreation Board Page A-11 Powderhorn Lake 1992-2015

2015 Water Resources Report – Minneapolis Park & Recreation Board Page A-12 Powderhorn Lake Nitrogen 1994-2015

2015 Water Resources Report – Minneapolis Park & Recreation Board Page A-13 Spring Lake 1994-2015

2015 Water Resources Report – Minneapolis Park & Recreation Board Page A-14 Spring Lake 1994- 2015 Nitrogen

2015 Water Resources Report – Minneapolis Park & Recreation Board Page A-15 Webber Pond 1992-2013  L g    a  Chlorophyll 0 100 200 300 400

1992 1994 1996 1998 2000 2002 2004 2006 2008 2010 2012  L g    Phosphorus  Total 0 100 200 300 400 500 600

1992 1994 1996 1998 2000 2002 2004 2006 2008 2010 2012  L mg   Nitrogen  Total 01234567

1994 1996 1998 2000 2002 2004 2006 2008 2010 2012

2015 Water Resources Report – Minneapolis Park & Recreation Board Page A-16 Wirth Lake 1992-2015

2015 Water Resources Report – Minneapolis Park & Recreation Board Page A-17 Wirth Lake 1994-2015 Nitrogen

2015 Water Resources Report – Minneapolis Park & Recreation Board Page A-18 Appendix B

This section contains lake monitoring data for 2015.

2015 Water Resources Report – Minneapolis Park & Recreation Board Page B-1

Date Time Secchi Depth DO pH SpCond TurbSC Chl‐a Pheo‐a Silica TP SRP TKN NO3NO2 Alk Hard SO4 K Ca Mg E. Coli Lake Name MM/DD/YYY HH:MM:SS meters meters Temp °C %DO mg/L units µS/cm NTU mg/M3 mg/M3 mg/L mg/L mg/L mg/L TN mg/L mg/L mg/L mg/L Cl mg/L mg/L mg/L mg/L mg/L mpn/100mL Calhoun 3/6/2015 11:54:14 0 0.72 89.7 12.56 8.13 779.1 0.6 9.00 1.27 <0.500 0.044 0.003 0.585 0.651 0.093 135 164 157 Calhoun 3/6/2015 11:53:36 1 2.86 91.2 12.04 8.11 757.9 0.6 Calhoun 3/6/2015 11:52:33 2 2.94 90.9 11.98 8.10 756.3 0.7 Calhoun 3/6/2015 11:52:04 3 2.94 90.9 11.98 8.10 756.3 0.6 Calhoun 3/6/2015 11:51:29 4 2.94 90.9 11.98 8.10 756.2 0.4 Calhoun 3/6/2015 11:50:59 5 2.94 90.9 11.98 8.09 756.4 0.5 Calhoun 3/6/2015 11:50:25 6 2.95 91.1 12.01 8.09 756.3 0.5 0.032 0.003 Calhoun 3/6/2015 11:49:16 7 2.95 90.7 11.95 8.08 756.3 0.4 Calhoun 3/6/2015 11:48:22 8 2.94 90.8 11.97 8.08 756.1 0.4 Calhoun 3/6/2015 11:47:43 9 2.92 89.7 11.82 8.06 756.8 0.4 Calhoun 3/6/2015 11:46:46 10 2.91 69.1 9.12 7.88 758.5 0.3 Calhoun 3/6/2015 11:46:08 11 2.90 49.4 6.51 7.59 764.7 0.3 Calhoun 3/6/2015 11:45:26 12 2.95 51.7 6.82 7.61 769.9 0.3 0.029 0.003 Calhoun 3/6/2015 11:44:38 13 2.95 48.1 6.34 7.58 774.8 0.3 Calhoun 3/6/2015 11:43:51 14 2.96 27.8 3.67 7.48 785.9 0.2 Calhoun 3/6/2015 11:43:18 15 2.92 20.8 2.74 7.41 798.4 0.2 Calhoun 3/6/2015 11:42:46 16 2.92 17.7 2.33 7.38 829.0 0.2 Calhoun 3/6/2015 11:42:24 17 2.97 22.2 2.92 7.40 840.8 0.1 Calhoun 3/6/2015 11:41:48 18 3.06 23.6 3.09 7.40 852.4 0.1 0.091 0.047 Calhoun 3/6/2015 11:40:57 19 3.09 19.4 2.54 7.36 884.2 0.0 Calhoun 3/6/2015 11:40:10 20 3.19 8.4 1.10 7.30 904.7 0.0 Calhoun 3/6/2015 11:39:34 21 3.26 0.0 0.00 7.25 916.0 0.0 Calhoun 3/6/2015 11:38:53 22 3.36 1.4 0.18 7.22 930.0 0.0 0.154 0.066 182 Calhoun 3/6/2015 11:37:58 23 3.42 0.0 0.00 7.15 934.4 0.0 Cedar 2/13/2015 12:10:40 0 0.78 75.6 10.58 7.55 798.8 6.30 5.93 3.350 0.054 0.003 1.145 1.295 0.232 156 200 146 Cedar 2/13/2015 12:09:53 1 2.75 60.9 8.07 7.49 784.6 Cedar 2/13/2015 12:09:06 2 2.75 61.4 8.14 7.48 784.6 Cedar 2/13/2015 12:08:30 3 2.75 58.2 7.72 7.47 784.6 Cedar 2/13/2015 12:08:01 4 2.77 49.5 6.55 7.41 787.5 Cedar 2/13/2015 12:07:04 5 2.79 35.9 4.74 7.36 837.4 0.032 0.006 Cedar 2/13/2015 12:06:24 6 2.77 38.2 5.06 7.35 864.5 Cedar 2/13/2015 12:05:15 7 2.83 30.9 4.08 7.32 893.7 Cedar 2/13/2015 12:04:41 8 2.84 27.5 3.63 7.30 921.3 Cedar 2/13/2015 12:03:42 9 3.02 15.1 1.98 7.25 943.5 Cedar 2/13/2015 12:02:43 10 3.10 3.2 0.41 7.22 955.0 0.047 0.029 Cedar 2/13/2015 12:02:13 11 3.10 1.2 0.15 7.20 969.0 Cedar 2/13/2015 12:01:50 12 3.09 1.2 0.15 7.19 976.7 Cedar 2/13/2015 12:01:28 13 3.12 1.6 0.21 7.16 986.9 Cedar 2/13/2015 12:01:05 14 3.24 2.4 0.32 7.13 999.8 0.129 0.078 163 Cedar 2/13/2015 12:00:42 15 3.38 3.0 0.39 7.06 1009.0 Harriet 2/13/2015 10:25:38 0 0.25 73.0 10.36 7.59 677.9 2.40 0.87 <0.500 0.069 0.045 0.739 0.944 0.103 123 148 121 Harriet 2/13/2015 10:24:59 1 2.48 71.6 9.56 7.57 655.6 Harriet 2/13/2015 10:24:36 2 2.48 70.8 9.45 7.55 655.8 Harriet 2/13/2015 10:23:57 3 2.48 71.9 9.61 7.53 655.8 Harriet 2/13/2015 10:23:28 4 2.48 71.2 9.51 7.54 656.1 Harriet 2/13/2015 10:22:51 5 2.49 71.1 9.49 7.51 656.5 Harriet 2/13/2015 10:22:20 6 2.49 69.9 9.33 7.50 657.5 0.072 0.047 Harriet 2/13/2015 10:21:25 7 2.51 66.3 8.85 7.48 659.5 Harriet 2/13/2015 10:20:44 8 2.55 62.9 8.38 7.47 660.7 Harriet 2/13/2015 10:20:02 9 2.58 53.4 7.11 7.42 663.1 Harriet 2/13/2015 10:19:11 10 2.63 43.1 5.72 7.38 666.7 Harriet 2/13/2015 10:18:30 11 2.67 40.8 5.42 7.38 669.5 Harriet 2/13/2015 10:17:57 12 2.71 33.7 4.47 7.36 673.0 0.083 0.071 Harriet 2/13/2015 10:17:15 13 2.77 22.7 3.01 7.34 675.9 Harriet 2/13/2015 10:16:26 14 2.84 8.9 1.18 7.32 683.1 Harriet 2/13/2015 10:15:51 15 2.86 5.3 0.70 7.33 700.5 0.126 0.108 Harriet 2/13/2015 10:15:26 16 2.91 4.0 0.53 7.33 717.7 Harriet 2/13/2015 10:14:51 17 2.90 5.0 0.67 7.33 728.8

2015 Water Resources Report - Minneapolis Park Recreation Board Page B1 Date Time Secchi Depth DO pH SpCond TurbSC Chl‐a Pheo‐a Silica TP SRP TKN NO3NO2 Alk Hard SO4 K Ca Mg E. Coli Lake Name MM/DD/YYY HH:MM:SS meters meters Temp °C %DO mg/L units µS/cm NTU mg/M3 mg/M3 mg/L mg/L mg/L mg/L TN mg/L mg/L mg/L mg/L Cl mg/L mg/L mg/L mg/L mg/L mpn/100mL Harriet 2/13/2015 10:14:29 18 2.92 3.4 0.45 7.34 742.6 Harriet 2/13/2015 10:13:54 19 2.95 3.7 0.49 7.35 760.6 Harriet 2/13/2015 10:13:12 20 2.94 14.4 1.90 7.39 781.7 0.183 0.166 126 Harriet 2/13/2015 10:12:44 21 2.99 15.2 2.00 7.40 793.2 Harriet 2/13/2015 10:12:10 22 3.09 9.5 1.24 7.41 799.4 Hiawatha 3/6/2015 13:39:56 0 0.82 124.2 17.32 8.03 1117.0 2.8 27.90 3.50 10.500 0.096 0.003 1.150 1.280 0.276 221 296 217 Hiawatha 3/6/2015 13:39:33 1 2.67 125.7 16.66 7.97 1117.0 2.4 Hiawatha 3/6/2015 13:38:43 2 2.67 113.5 15.04 7.89 1117.0 2.2 Hiawatha 3/6/2015 13:38:06 3 2.68 76.9 10.19 7.65 1188.0 2.2 Hiawatha 3/6/2015 13:36:59 4 3.21 4.5 0.59 7.32 1521.0 2.2 0.070 0.004 242 Hiawatha 3/6/2015 13:36:23 5 3.39 0.0 0.00 7.30 1561.0 2.4 Hiawatha 3/6/2015 13:35:44 6 3.65 0.0 0.00 7.29 1591.0 3.0 Isles 2/13/2015 11:24:47 0 1.68 43.1 5.88 7.45 770.5 5.80 1.13 2.920 0.061 <0.003 1.190 1.240 0.332 145 172 155 Isles 2/13/2015 11:24:18 1 3.51 43.3 5.64 7.39 775.1 Isles 2/13/2015 11:23:34 2 3.59 39.1 5.06 7.37 775.3 Isles 2/13/2015 11:22:11 3 4.00 18.5 2.37 7.34 783.4 Isles 2/13/2015 11:20:55 4 4.07 11.2 1.44 7.34 790.1 Isles 2/13/2015 11:19:59 5 4.05 22.9 2.93 7.38 795.1 0.056 0.025 Isles 2/13/2015 11:19:07 6 4.08 25.2 3.22 7.40 800.5 Isles 2/13/2015 11:18:27 7 4.12 29.9 3.81 7.42 806.1 Isles 2/13/2015 11:17:22 8 4.17 28.2 3.60 7.44 811.9 0.044 0.017 Isles 2/13/2015 11:16:13 9 4.18 7.5 0.96 7.42 806.0 Loring 2/15/2015 10:46:56 0 0.89 59 8.22 7.63 1913 28.9 23.5 20.6 0.325 0.100 1.66 2.19 0.164 245 328 449 Loring 2/14/2015 10:45:46 1 2.95 22.1 2.92 7.6 1907 Loring 2/13/2015 10:44:28 2 3.2 15.4 2.01 7.6 1914 Loring 2/12/2015 10:43:24 3 5.04 2.2 0.27 7.58 2354 Loring 2/11/2015 10:42:48 4 6.61 2.8 0.34 7.47 3798 0.555 0.438 470 Nokomis 3/6/2015 12:58:43 0 1.10 54.7 7.59 7.82 538.3 3.9 9.40 0.78 2.460 0.042 0.003 0.897 0.885 0.056 135 136 107 Nokomis 3/6/2015 12:57:56 1 3.81 59.3 7.64 8.04 587.4 3.5 Nokomis 3/6/2015 12:57:12 2 3.80 59.5 7.67 8.02 587.5 3.3 Nokomis 3/6/2015 12:56:23 3 3.79 59.0 7.61 8.01 587.6 2.9 Nokomis 3/6/2015 12:55:44 4 3.82 54.2 6.98 7.98 587.8 2.2 0.037 <0.003 Nokomis 3/6/2015 12:55:11 5 4.18 31.4 4.01 7.73 596.2 2.1 Nokomis 3/6/2015 12:54:07 6 4.47 19.3 2.44 7.56 609.8 1.8 Nokomis 3/6/2015 12:53:03 7 4.73 0.0 0.00 7.43 632.5 0.6 0.041 0.003 117 Powderhorn 2/11/2015 11:53:53 0 1.70 78.5 10.77 8.35 469.4 38.10 27.70 1.660 0.150 0.005 1.570 2.000 0.070 50 52 96 Powderhorn 2/11/2015 11:53:33 1 3.50 81.5 10.64 8.26 489.1 Powderhorn 2/11/2015 11:52:12 2 4.28 13.9 1.78 7.94 661.2 Powderhorn 2/11/2015 11:51:43 3 4.70 8.2 1.03 7.87 1243.0 Powderhorn 2/11/2015 11:51:06 4 4.76 8.7 1.09 7.85 1384.0 0.061 0.014 Powderhorn 2/11/2015 11:49:19 5 4.76 2.3 0.29 7.84 1468.0 Powderhorn 2/11/2015 6 0.145 0.014 390 Spring 2/11/2015 11:10:52 0 0.47 3.3 0.46 7.23 3432 118 31.8 21.9 0.892 0.571 3.85 4.52 0.152 420 840 864 Spring 2/11/2015 11:10:08 1 1.67 3.2 0.44 7.21 3432 Spring 2/11/2015 11:09:17 2 4.01 2.2 0.29 7.1 3662 Spring 2/11/2015 11:08:46 3 5.7 1.9 0.23 6.97 4527 Spring 2/11/2015 11:08:13 4 6.76 2.2 0.26 6.92 4977 Spring 2/11/2015 11:07:42 5 6.99 2.6 0.31 6.89 5245 Spring 2/11/2015 11:07:21 6 7.11 3.4 0.39 6.89 5339 Spring 2/11/2015 11:06:49 7 6.69 4.8 0.56 6.9 5496 Wirth 2/12/2015 14:33:50 0 1.41 26.2 3.66 7.67 948.9 6.88 5.80 12.2 0.032 0.009 0.662 0.805 0.316 202 292 185 Wirth 2/12/2015 14:33:19 1 3.19 28.1 3.74 7.65 960 Wirth 2/12/2015 14:32:45 2 3.41 27.6 3.64 7.62 964 Wirth 2/12/2015 14:30:59 3 3.98 8.8 1.15 7.59 955.6 Wirth 2/12/2015 14:29:51 4 4.14 0.8 0.1 7.6 975.5 0.033 0.014 Wirth 2/12/2015 14:29:08 5 4.35 0 0 7.59 1031 Wirth 2/12/2015 14:28:36 6 4.64 0.1 0.01 7.59 1151 Wirth 2/12/2015 14:28:00 7 4.96 1.4 0.16 7.47 1850 0.059 0.029 205

2015 Water Resources Report - Minneapolis Park Recreation Board Page B2 Date Time Secchi Depth DO pH SpCond TurbSC Chl‐a Pheo‐a Silica TP SRP TKN NO3NO2 Alk Hard SO4 K Ca Mg E. Coli Lake Name MM/DD/YYY HH:MM:SS meters meters Temp °C %DO mg/L units µS/cm NTU mg/M3 mg/M3 mg/L mg/L mg/L mg/L TN mg/L mg/L mg/L mg/L Cl mg/L mg/L mg/L mg/L mg/L mpn/100mL Wirth 2/12/2015 14:27:16 7.7 5.38 1.7 0.21 7.28 4723 Calhoun 4/14/2015 10:02:29 4.50 0 7.76 100.8 11.82 8.25 734.5 1.6 1.10 1.05 <0.500 0.021 0.003 0.592 0.771 0.174 128 156 150 8.23 4.2 44 12 Calhoun 4/14/2015 10:02:04 1 7.70 100.7 11.83 8.24 734.2 1.6 Calhoun 4/14/2015 10:01:31 2 7.54 99.7 11.76 8.21 734.3 1.6 Calhoun 4/14/2015 10:00:34 3 7.40 98.7 11.67 8.19 734.7 1.5 Calhoun 4/14/2015 9:59:42 4 7.36 98.7 11.69 8.17 734.7 1.5 Calhoun 4/14/2015 9:59:05 5 7.33 99.2 11.75 8.17 735.0 1.5 Calhoun 4/14/2015 9:58:07 6 7.33 98.2 11.63 8.17 734.5 1.5 0.038 0.003 Calhoun 4/14/2015 9:57:40 7 7.31 98.2 11.64 8.17 734.9 1.4 Calhoun 4/14/2015 9:57:11 8 7.30 98.5 11.68 8.16 734.8 1.4 Calhoun 4/14/2015 9:56:43 9 7.26 98.5 11.69 8.15 735.0 1.4 Calhoun 4/14/2015 9:56:13 10 7.18 96.3 11.46 8.13 735.0 1.4 Calhoun 4/14/2015 9:55:42 11 7.04 96.0 11.46 8.10 735.8 1.4 Calhoun 4/14/2015 9:54:29 12 6.95 94.5 11.31 8.09 736.0 1.4 0.023 0.003 Calhoun 4/14/2015 9:53:52 13 6.90 94.1 11.27 8.07 735.9 1.4 Calhoun 4/14/2015 9:53:20 14 6.80 93.1 11.18 8.05 736.8 1.4 Calhoun 4/14/2015 9:52:55 15 6.72 92.7 11.15 8.04 736.9 1.4 Calhoun 4/14/2015 9:51:59 16 6.70 92.3 11.11 8.02 736.8 1.5 Calhoun 4/14/2015 9:51:04 17 6.69 91.6 11.03 8.00 737.1 1.8 Calhoun 4/14/2015 9:50:43 18 6.63 90.9 10.96 7.99 738.0 1.3 0.022 0.003 Calhoun 4/14/2015 9:50:16 19 6.62 90.5 10.92 7.97 738.1 1.3 Calhoun 4/14/2015 9:49:39 20 6.35 85.1 10.33 7.87 741.9 1.5 Calhoun 4/14/2015 9:49:12 21 6.21 83.4 10.17 7.82 744.8 1.4 Calhoun 4/14/2015 9:48:29 22 6.08 78.2 9.57 7.73 748.6 2.3 0.023 0.005 160 8.28 Calhoun 4/14/2015 9:47:43 23 5.54 64.5 8.00 7.54 765.6 1.4 Cedar 4/16/2015 11:25:27 1.17 0 11.50 126.5 13.47 8.61 791.3 2.2 3.20 2.80 1.858 0.060 <0.003 0.752 1.060 0.120 153 192 148 15.00 4.4 55 16 Cedar 4/16/2015 11:25:06 1 11.22 126.4 13.55 8.59 791.0 2.1 Cedar 4/16/2015 11:24:16 2 11.03 125.4 13.50 8.59 790.8 2.0 Cedar 4/16/2015 11:23:21 3 10.46 119.9 13.08 8.49 790.8 1.9 Cedar 4/16/2015 11:22:30 4 9.86 108.7 12.03 8.35 790.2 1.9 Cedar 4/16/2015 11:21:46 5 8.63 93.1 10.61 8.12 790.1 1.8 0.049 0.003 Cedar 4/16/2015 11:21:16 6 8.49 91.8 10.50 8.12 791.5 1.8 Cedar 4/16/2015 11:20:29 7 8.25 87.7 10.09 8.09 791.6 1.7 Cedar 4/16/2015 11:19:10 8 8.00 86.1 9.97 8.05 793.2 1.7 Cedar 4/16/2015 11:18:15 9 7.87 84.9 9.86 8.03 792.2 1.7 Cedar 4/16/2015 11:17:09 10 7.65 81.9 9.56 8.02 793.9 1.7 0.041 0.003 Cedar 4/16/2015 11:15:56 11 7.52 79.5 9.31 7.98 794.9 1.9 Cedar 4/16/2015 11:14:38 12 7.26 75.0 8.84 7.92 796.8 2.2 Cedar 4/16/2015 11:13:05 13 6.10 42.5 5.15 7.69 817.3 3.1 Cedar 4/16/2015 11:11:23 14 4.66 0.0 0.00 7.51 902.1 7.6 0.044 0.003 148 13.40 Cedar 4/16/2015 11:10:29 15 4.43 0.0 0.00 7.48 930.4 12.5 Cedar 4/16/2015 11:09:45 15.3 4.37 0.0 0.00 7.47 934.8 14.2 Diamond 4/15/2015 9:29:35 0 14.24 97.7 9.83 8.02 1011.0 4.4 5.53 4.75 0.633 0.093 0.005 0.833 1.070 0.066 74 88 259 5.96 Diamond 4/15/2015 9:29:11 0.4 14.25 80.0 8.05 8.03 1010.0 140.6 Harriet 4/16/2015 10:03:28 2.30 0 8.43 113.6 13.01 8.49 645.9 1.2 4.01 2.20 <0.500 0.055 0.015 0.680 0.827 0.124 120 140 124 7.32 4.1 40 12 Harriet 4/16/2015 10:02:29 1 8.40 113.8 13.04 8.49 645.8 1.1 Harriet 4/16/2015 10:02:05 2 8.30 112.1 12.89 8.47 645.6 1.1 Harriet 4/16/2015 10:01:45 3 8.03 110.8 12.82 8.42 646.5 1.1 Harriet 4/16/2015 10:01:06 4 7.93 109.4 12.69 8.40 645.9 1.1 Harriet 4/16/2015 10:00:37 5 7.91 109.2 12.67 8.39 645.9 1.0 Harriet 4/16/2015 10:00:10 6 7.89 108.1 12.55 8.38 645.7 1.0 0.059 0.020 Harriet 4/16/2015 9:59:36 7 7.87 108.0 12.55 8.37 645.9 1.0 Harriet 4/16/2015 9:58:35 8 7.48 105.3 12.35 8.33 645.4 1.0 Harriet 4/16/2015 9:58:05 9 7.27 104.3 12.29 8.30 645.8 1.0 Harriet 4/16/2015 9:57:20 10 7.14 102.4 12.11 8.28 645.7 1.0 Harriet 4/16/2015 9:56:56 11 6.95 100.9 11.99 8.25 645.9 1.0 Harriet 4/16/2015 9:56:30 12 6.89 100.6 11.97 8.24 646.0 1.0 0.051 0.027 Harriet 4/16/2015 9:56:03 13 6.84 100.3 11.95 8.24 646.6 1.0

2015 Water Resources Report - Minneapolis Park Recreation Board Page B3 Date Time Secchi Depth DO pH SpCond TurbSC Chl‐a Pheo‐a Silica TP SRP TKN NO3NO2 Alk Hard SO4 K Ca Mg E. Coli Lake Name MM/DD/YYY HH:MM:SS meters meters Temp °C %DO mg/L units µS/cm NTU mg/M3 mg/M3 mg/L mg/L mg/L mg/L TN mg/L mg/L mg/L mg/L Cl mg/L mg/L mg/L mg/L mg/L mpn/100mL Harriet 4/16/2015 9:55:39 14 6.83 100.5 11.98 8.24 646.3 0.9 Harriet 4/16/2015 9:55:13 15 6.84 100.1 11.92 8.23 645.6 0.9 0.053 0.022 Harriet 4/16/2015 9:54:35 16 6.81 99.8 11.90 8.22 646.3 1.0 Harriet 4/16/2015 9:54:07 17 6.76 98.8 11.79 8.20 646.7 0.9 Harriet 4/16/2015 9:53:35 18 6.53 95.4 11.45 8.15 646.6 1.0 Harriet 4/16/2015 9:52:48 19 6.51 95.3 11.44 8.12 646.2 1.0 Harriet 4/16/2015 9:52:14 20 6.51 95.8 11.51 8.11 647.5 1.0 0.051 0.023 124 7.36 Harriet 4/16/2015 9:51:53 21 6.50 96.3 11.57 8.10 647.5 1.0 Harriet 4/16/2015 9:51:30 22 6.51 95.8 11.51 8.08 647.0 1.1 Harriet 4/16/2015 9:51:07 23 6.55 95.5 11.47 8.06 645.4 1.2 Harriet 4/16/2015 9:50:10 24 6.47 95.6 11.50 7.97 647.5 1.2 Hiawatha 4/17/2015 10:35:56 0.80 0 14.34 146.9 14.70 8.73 951.0 3.5 13.00 8.80 3.147 0.070 0.003 1.110 0.905 <0.030 163 204 191 12.90 Hiawatha 4/17/2015 10:35:30 1 13.93 144.6 14.60 8.73 949.4 3.4 Hiawatha 4/17/2015 10:34:14 2 12.93 127.6 13.19 8.59 954.8 3.3 Hiawatha 4/17/2015 10:33:15 3 11.56 95.5 10.17 8.16 967.1 3.3 Hiawatha 4/17/2015 10:31:42 4 10.11 59.8 6.59 7.75 993.1 3.5 0.082 0.003 196 13.50 Hiawatha 4/17/2015 10:30:24 5 9.17 51.1 5.75 7.70 1009.0 3.6 Hiawatha 4/17/2015 10:29:14 6 7.58 63.6 7.44 7.76 1036.0 3.1 Hiawatha 4/17/2015 10:27:30 7 5.42 0.0 0.00 7.25 2078.0 2.9 Hiawatha 4/17/2015 10:26:45 7.7 4.75 0.0 0.00 7.21 2265.0 6.8 Isles 4/14/2015 10:36:01 1.05 0 11.27 115.1 12.42 8.64 740.3 3.1 2.50 2.36 <0.500 0.071 <0.003 <0.500 0.579 0.036 123 144 155 7.52 Isles 4/14/2015 10:35:33 1 11.08 114.4 12.39 8.63 740.8 3.1 Isles 4/14/2015 10:34:53 2 10.98 113.4 12.32 8.62 741.6 3.0 Isles 4/14/2015 10:34:17 3 10.85 112.7 12.28 8.60 740.3 3.0 Isles 4/14/2015 10:33:16 4 10.61 108.6 11.89 8.55 739.4 2.9 Isles 4/14/2015 10:32:27 5 8.91 99.6 11.36 8.33 745.0 2.8 0.036 <0.003 Isles 4/14/2015 10:31:33 6 8.17 91.8 10.65 8.19 744.0 2.7 Isles 4/14/2015 10:30:37 7 7.63 88.1 10.36 8.13 744.1 2.6 Isles 4/14/2015 10:29:20 8 7.50 85.2 10.05 8.05 744.4 2.6 0.030 <0.003 155 7.84 Isles 4/14/2015 10:28:25 9 7.28 74.4 8.83 7.88 746.5 10.5 Loring 4/15/2015 10:44:54 3.07 0 12.99 73.2 7.54 7.78 1827 2.2 1.7 <0.500 16.1 0.196 0.124 1.03 1.28 0.086 216 304 442 18.9 Loring 4/15/2015 10:44:21 1 12.94 72.9 7.53 7.77 1822 2.3 Loring 4/15/2015 10:43:43 2 12.92 72.8 7.52 7.76 1823 2.4 Loring 4/15/2015 10:43:14 3 12.93 72.3 7.47 7.75 1826 2.6 Loring 4/15/2015 10:42:27 4 12.75 61.2 6.34 7.67 1824 2.3 0.224 0.125 464 16.6 Nokomis 4/17/2015 9:39:10 1.50 0 9.71 69.7 7.76 7.97 556.6 34.1 7.10 1.10 <0.500 0.041 <0.003 0.552 0.570 0.030 114 120 95 7.16 4.1 43 6 Nokomis 4/17/2015 9:38:51 1 9.99 86.0 9.51 8.30 547.8 4.5 Nokomis 4/17/2015 9:38:13 2 9.97 92.4 10.22 8.39 547.3 3.7 Nokomis 4/17/2015 9:37:49 3 10.22 92.7 10.21 8.39 548.2 4.0 Nokomis 4/17/2015 9:35:46 4 11.30 118.9 12.76 8.67 536.8 3.8 0.040 <0.003 Nokomis 4/17/2015 9:35:06 5 11.64 131.5 14.00 8.72 534.5 3.1 Nokomis 4/17/2015 9:34:01 6 12.13 131.4 13.83 8.74 534.3 3.1 Nokomis 4/17/2015 9:32:04 7 12.71 131.0 13.61 8.75 536.0 3.1 0.035 <0.003 90 6.33 Nokomis 4/17/2015 9:31:01 8 12.79 131.2 13.60 8.75 535.3 3.0 Powderhorn 4/15/2015 10:03:32 0.53 0 12.30 96.3 10.13 7.61 757.7 6.1 6.20 5.20 1.664 0.152 0.008 1.300 1.530 0.087 46 56 202 7.28 Powderhorn 4/15/2015 10:03:01 1 12.30 96.4 10.14 7.61 757.9 6.1 Powderhorn 4/15/2015 10:02:20 2 12.30 96.6 10.17 7.61 757.8 6.3 Powderhorn 4/15/2015 10:01:45 3 12.30 96.3 10.13 7.61 758.2 6.3 Powderhorn 4/15/2015 10:00:54 4 12.27 95.8 10.08 7.60 758.0 6.8 0.147 0.006 Powderhorn 4/15/2015 10:00:04 5 12.24 94.9 9.99 7.57 758.0 7.3 Powderhorn 4/15/2015 9:59:05 6 12.18 92.1 9.70 7.54 758.6 9.8 0.141 0.012 216 7.28 Powderhorn 4/15/2015 9:58:21 6.3 12.15 91.5 9.66 7.51 758.5 14.1 Spring 4/15/2015 11:19:49 0.78 0 13.65 130.2 13.2 8.29 2638 9.3 179 52.5 21.5 0.602 0.100 2.67 2.24 <0.030 374 680 842 97.4 Spring 4/15/2015 11:18:21 1 10.26 400.7 43.73 8.18 3522 12.3 Spring 4/15/2015 11:15:45 2 5.38 0 0 6.83 3803 14.3 Spring 4/15/2015 11:15:09 3 4.89 0 0 6.68 4454 15.4 Spring 4/15/2015 11:14:34 4 5.88 0 0 6.59 4887 16.4 Spring 4/15/2015 11:13:47 5 6.51 0 0 6.54 5117 18.4

2015 Water Resources Report - Minneapolis Park Recreation Board Page B4 Date Time Secchi Depth DO pH SpCond TurbSC Chl‐a Pheo‐a Silica TP SRP TKN NO3NO2 Alk Hard SO4 K Ca Mg E. Coli Lake Name MM/DD/YYY HH:MM:SS meters meters Temp °C %DO mg/L units µS/cm NTU mg/M3 mg/M3 mg/L mg/L mg/L mg/L TN mg/L mg/L mg/L mg/L Cl mg/L mg/L mg/L mg/L mg/L mpn/100mL Spring 4/15/2015 11:13:04 6 6.84 0 0 6.51 5270 21.4 Spring 4/15/2015 11:11:59 7 7.02 0 0 6.47 5429 28 Wirth 4/16/2015 12:03:44 0.84 0 13.04 124.6 12.8 8.47 967 1.9 2.70 1.60 11.2 0.035 0.003 <0.500 0.559 <0.030 208 296 177 13.4 4.40 72.0 32.0 Wirth 4/16/2015 12:03:00 1 12.72 124.8 12.92 8.46 965.1 1.7 Wirth 4/16/2015 12:02:19 2 12.44 122.4 12.75 8.44 965.4 1.7 Wirth 4/16/2015 12:01:26 3 10.79 107.6 11.64 8.28 959.2 1.7 Wirth 4/16/2015 12:00:46 4 9.22 84.8 9.52 8.01 971 1.7 0.037 0.003 Wirth 4/16/2015 11:59:28 5 8.88 76.7 8.68 7.92 974 1.8 Wirth 4/16/2015 11:58:34 6 8.44 60.2 6.89 7.79 978.2 2 Wirth 4/16/2015 11:57:38 7 7.88 45.5 5.27 7.68 998.6 2.6 0.035 0.003 177 13.3 Calhoun 5/4/2015 10:59:49 3.80 0 14.21 120.0 12.07 8.63 724.5 5.6 1.80 <0.500 <0.500 0.022 0.003 0.579 149 Calhoun 5/4/2015 10:59:23 1 14.18 120.3 12.11 8.64 724.6 5.5 Calhoun 5/4/2015 10:58:26 2 14.15 120.4 12.13 8.63 724.0 5.2 Calhoun 5/4/2015 10:57:46 3 13.87 119.7 12.13 8.62 724.2 4.9 Calhoun 5/4/2015 10:56:46 4 13.38 117.7 12.05 8.57 722.6 4.6 Calhoun 5/4/2015 10:55:56 5 11.42 111.5 11.94 8.44 721.0 4.4 Calhoun 5/4/2015 10:54:55 6 9.85 105.5 11.71 8.36 720.2 4.2 0.021 0.003 Calhoun 5/4/2015 10:54:07 7 9.40 103.1 11.57 8.32 720.2 4.1 Calhoun 5/4/2015 10:52:57 8 8.95 98.3 11.15 8.25 719.7 4.0 Calhoun 5/4/2015 10:52:14 9 8.68 94.3 10.76 8.19 720.0 4.0 Calhoun 5/4/2015 10:51:05 10 8.59 92.3 10.57 8.16 720.3 3.8 Calhoun 5/4/2015 10:50:04 11 8.44 88.9 10.21 8.15 720.7 3.2 Calhoun 5/4/2015 10:48:22 12 8.28 87.3 10.07 8.08 720.3 2.9 0.017 0.003 Calhoun 5/4/2015 10:47:42 13 8.15 84.2 9.74 8.04 720.9 2.8 Calhoun 5/4/2015 10:46:53 14 8.10 82.7 9.58 8.03 720.5 2.6 Calhoun 5/4/2015 10:45:55 15 8.01 81.5 9.46 8.01 722.3 2.4 Calhoun 5/4/2015 10:45:19 16 8.01 81.3 9.43 8.00 721.2 2.3 Calhoun 5/4/2015 10:44:35 17 7.98 79.4 9.22 7.99 721.2 2.2 Calhoun 5/4/2015 10:43:49 18 7.97 79.2 9.20 7.98 722.1 2.0 0.027 0.019 Calhoun 5/4/2015 10:42:14 19 7.94 77.8 9.05 7.97 721.6 1.7 Calhoun 5/4/2015 10:41:02 20 7.94 77.4 9.00 7.97 723.0 1.4 Calhoun 5/4/2015 10:40:03 21 7.93 76.5 8.90 7.97 722.9 18.6 Calhoun 5/4/2015 22 0.042 149 Cedar 5/4/2015 12:10:52 2.45 0 16.08 130.8 12.63 8.75 782.7 4.3 3.00 0.50 0.823 0.034 <0.003 0.709 153 Cedar 5/4/2015 12:10:23 1 16.03 131.8 12.74 8.76 783.2 4.1 Cedar 5/4/2015 12:09:50 2 15.90 131.7 12.77 8.76 782.1 4.0 Cedar 5/4/2015 12:08:59 3 13.38 124.1 12.71 8.64 778.2 3.8 Cedar 5/4/2015 12:08:07 4 10.71 107.7 11.72 8.46 775.8 3.7 Cedar 5/4/2015 12:07:19 5 9.83 80.2 8.91 8.11 777.6 3.6 0.061 <0.003 Cedar 5/4/2015 12:06:31 6 9.51 70.5 7.89 8.01 778.2 3.4 Cedar 5/4/2015 12:06:01 7 9.24 66.4 7.48 7.95 779.2 3.4 Cedar 5/4/2015 12:05:19 8 8.95 60.3 6.84 7.90 778.8 3.3 Cedar 5/4/2015 12:04:24 9 8.51 42.1 4.82 7.73 779.7 3.3 Cedar 5/4/2015 12:03:45 10 8.14 32.0 3.71 7.66 781.7 3.3 0.040 0.014 Cedar 5/4/2015 12:02:55 11 7.81 21.4 2.50 7.60 784.0 3.5 Cedar 5/4/2015 12:01:36 12 6.92 0.0 0.00 7.52 799.5 5.0 Cedar 5/4/2015 12:01:00 13 6.40 0.0 0.00 7.52 820.1 6.0 Cedar 5/4/2015 12:00:17 14 5.88 0.0 0.00 7.50 844.2 6.5 0.124 0.057 158 Cedar 5/4/2015 11:59:28 15 5.67 0.0 0.00 7.47 854.5 325.0 Diamond 5/6/2015 9:24:46 0 18.00 70.1 6.48 8.07 1128.0 3.7 5.60 5.50 1.353 0.074 0.003 0.891 288 Harriet 5/5/2015 10:05:31 6.29 0 14.42 113.6 11.39 8.58 651.3 3.2 1.90 <0.500 <0.500 0.046 0.016 0.640 129 Harriet 5/5/2015 10:05:06 1 14.40 113.8 11.41 8.58 651.3 3.2 Harriet 5/5/2015 10:04:15 2 14.37 114.0 11.44 8.58 651.1 3.0 Harriet 5/5/2015 10:03:30 3 14.24 113.4 11.42 8.56 651.5 2.8 Harriet 5/5/2015 10:02:15 4 13.34 106.7 10.96 8.42 649.6 2.5 Harriet 5/5/2015 10:01:24 5 10.73 96.5 10.51 8.23 649.0 2.5 Harriet 5/5/2015 10:00:32 6 8.84 88.8 10.12 8.14 647.7 2.4 0.057 0.025 Harriet 5/5/2015 9:59:48 7 8.72 87.6 10.01 8.12 647.6 2.4

2015 Water Resources Report - Minneapolis Park Recreation Board Page B5 Date Time Secchi Depth DO pH SpCond TurbSC Chl‐a Pheo‐a Silica TP SRP TKN NO3NO2 Alk Hard SO4 K Ca Mg E. Coli Lake Name MM/DD/YYY HH:MM:SS meters meters Temp °C %DO mg/L units µS/cm NTU mg/M3 mg/M3 mg/L mg/L mg/L mg/L TN mg/L mg/L mg/L mg/L Cl mg/L mg/L mg/L mg/L mg/L mpn/100mL Harriet 5/5/2015 9:58:32 8 8.57 84.5 9.69 8.06 647.6 2.3 Harriet 5/5/2015 9:57:32 9 8.39 82.6 9.51 8.03 648.1 2.2 Harriet 5/5/2015 9:56:09 10 8.19 76.5 8.85 7.95 648.3 2.1 Harriet 5/5/2015 9:55:24 11 8.07 73.5 8.54 7.92 648.9 2.1 Harriet 5/5/2015 9:54:25 12 8.00 73.5 8.55 7.90 648.8 2.1 0.068 0.046 Harriet 5/5/2015 9:53:47 13 7.99 73.3 8.52 7.90 648.4 2.0 Harriet 5/5/2015 9:53:11 14 7.97 71.9 8.37 7.88 648.9 2.0 Harriet 5/5/2015 9:52:27 15 7.91 70.4 8.20 7.87 649.6 2.0 0.067 0.053 Harriet 5/5/2015 9:50:57 16 7.86 68.2 7.96 7.84 648.6 2.1 Harriet 5/5/2015 9:50:07 17 7.83 66.8 7.80 7.82 650.2 2.4 Harriet 5/5/2015 9:49:18 18 7.82 64.5 7.53 7.80 650.3 2.4 Harriet 5/5/2015 9:47:06 19 7.77 60.6 7.09 7.79 650.2 9.2 Harriet 5/5/2015 20 0.077 0.061 129 Hiawatha 5/8/2015 14:06:16 2.80 0 16.96 84.0 7.91 8.12 938.7 3.2 2.00 1.30 1.000 0.053 0.009 0.906 182 Hiawatha 5/8/2015 14:05:48 1 16.96 83.5 7.87 8.12 938.6 3.1 Hiawatha 5/8/2015 14:04:56 2 16.85 82.6 7.80 8.09 938.2 2.9 Hiawatha 5/8/2015 14:03:51 3 16.23 71.9 6.88 7.94 934.2 2.8 Hiawatha 5/8/2015 14:02:18 4 11.98 8.4 0.88 7.58 972.1 3.6 0.069 0.026 182 Isles 5/4/2015 11:31:13 2.29 0 16.82 127.7 12.14 8.84 727.0 4.3 1.80 1.50 0.528 0.030 <0.003 0.678 153 Isles 5/4/2015 11:30:40 1 16.79 127.5 12.14 8.84 726.5 4.1 Isles 5/4/2015 11:29:48 2 16.79 127.2 12.11 8.83 725.5 3.9 Isles 5/4/2015 11:29:15 3 13.75 114.0 11.58 8.61 723.8 3.6 Isles 5/4/2015 11:28:15 4 11.11 103.1 11.12 8.48 727.2 3.5 Isles 5/4/2015 11:27:09 5 10.47 76.3 8.35 8.06 727.7 3.4 0.060 <0.003 Isles 5/4/2015 11:26:38 6 10.18 65.2 7.19 7.91 726.9 3.4 Isles 5/4/2015 11:25:41 7 9.95 53.5 5.93 7.80 727.5 3.7 Isles 5/4/2015 11:24:22 8 9.74 38.0 4.23 7.71 729.1 4.6 0.034 <0.003 153 Isles 5/4/2015 11:23:39 9 9.52 21.3 2.38 7.66 730.6 6.4 Loring 5/6/2015 10:58:38 2.45 0 17.86 74.4 6.88 7.9 1791 4.7 2.1 1.3 9.6 0.1 0.1 0.8 422.0 Loring 5/6/2015 10:57:49 1 17.85 74 6.85 7.9 1797 4.8 Loring 5/6/2015 10:57:02 2 17.83 74.2 6.87 7.89 1788 4.9 Loring 5/6/2015 10:56:08 3 17.83 72.7 6.73 7.88 1797 5.3 Loring 5/6/2015 10:55:24 4 17.75 69.9 6.48 7.85 1786 5.9 0.137 0.078 427 Nokomis 5/8/2015 13:07:28 2.05 0 16.48 110.5 10.53 8.75 542.9 5.0 8.50 0.80 0.528 0.037 <0.003 0.595 96 Nokomis 5/8/2015 13:06:57 1 16.49 110.2 10.51 8.74 541.4 5.1 Nokomis 5/8/2015 13:06:26 2 16.47 110.3 10.51 8.73 542.5 4.9 Nokomis 5/8/2015 13:05:52 3 16.36 109.6 10.47 8.67 543.1 3.7 Nokomis 5/8/2015 13:04:52 4 15.86 96.6 9.33 8.50 547.2 3.8 0.038 <0.003 Nokomis 5/8/2015 13:03:39 5 13.19 72.8 7.45 8.12 551.8 4.4 Nokomis 5/8/2015 13:02:23 6 11.69 55.1 5.84 7.85 551.2 4.1 Nokomis 5/8/2015 13:01:37 7 10.56 10.5 1.14 7.62 555.8 4.0 0.058 <0.003 96 Nokomis 5/8/2015 13:01:04 7.7 10.35 6.2 0.68 7.65 554.5 4.1 Powderhorn 5/6/2015 10:07:19 0.61 0 17.33 90.2 8.46 7.57 780.4 6.1 20.40 12.40 1.884 0.134 0.003 1.470 197 Powderhorn 5/6/2015 10:06:16 1 17.34 89.5 8.39 7.57 780.4 6.1 Powderhorn 5/6/2015 10:05:37 2 17.34 89.9 8.43 7.58 779.9 6.2 Powderhorn 5/6/2015 10:05:00 3 17.35 90.2 8.46 7.59 779.3 6.3 Powderhorn 5/6/2015 10:04:00 4 17.35 90.3 8.47 7.61 780.1 6.3 0.117 <0.003 Powderhorn 5/6/2015 10:03:21 5 17.35 90.0 8.44 7.62 780.5 6.5 Powderhorn 5/6/2015 10:02:43 6 17.34 88.6 8.31 7.62 780.2 6.8 0.122 <0.003 Spring 5/6/2015 11:42:58 1.71 0 17.8 42.6 3.93 7.7 2955 6.7 3.5 0.6 13.9 0.124 0.168 1.47 716 Spring 5/6/2015 11:41:55 1 17.07 196.6 18.4 7.66 3078 9.3 Spring 5/6/2015 11:40:50 2 9.58 0 0 6.67 3859 14 Spring 5/6/2015 11:40:02 3 5.76 0 0 6.63 4476 15.9 Spring 5/6/2015 11:39:25 4 5.94 0 0 6.54 4894 17.9 Spring 5/6/2015 11:38:14 5 6.56 0 0 6.5 5124 22.1 Spring 5/6/2015 11:37:42 6 6.94 0 0 6.47 5262 24.1 Spring 5/6/2015 11:36:59 6.8 7.01 0 0 6.45 5372 46.8 Wirth 5/5/2015 11:12:13 1.35 0 17.34 112.2 10.56 8.36 974.9 3.6 1.40 1.10 6.43 0.022 0.003 0.503 172

2015 Water Resources Report - Minneapolis Park Recreation Board Page B6 Date Time Secchi Depth DO pH SpCond TurbSC Chl‐a Pheo‐a Silica TP SRP TKN NO3NO2 Alk Hard SO4 K Ca Mg E. Coli Lake Name MM/DD/YYY HH:MM:SS meters meters Temp °C %DO mg/L units µS/cm NTU mg/M3 mg/M3 mg/L mg/L mg/L mg/L TN mg/L mg/L mg/L mg/L Cl mg/L mg/L mg/L mg/L mg/L mpn/100mL Wirth 5/5/2015 11:11:30 1 17.27 112 10.55 8.35 973.4 3.5 Wirth 5/5/2015 11:10:43 2 16.99 108.5 10.29 8.33 973.9 3.5 Wirth 5/5/2015 11:09:49 3 13.5 115.3 11.79 8.34 966.7 3.6 Wirth 5/5/2015 11:08:48 4 11.28 105.7 11.36 8.3 964.9 3.9 0.037 0.003 Wirth 5/5/2015 11:07:21 5 10.09 37.1 4.09 7.72 972.4 4.7 Wirth 5/5/2015 11:04:55 6 8.96 0 0 7.47 999.4 8.4 Wirth 5/5/2015 11:03:52 7 8.39 0 0 7.41 1073 10 0.059 0.003 191 Calhoun 5/20/2015 9:40:06 2.75 0 14.02 110.5 11.21 8.83 752.0 0.0 2.00 0.50 0.019 0.003 0.547 149 Calhoun 5/20/2015 9:39:42 1 14.00 111.0 11.26 8.82 752.3 0.0 Calhoun 5/20/2015 9:38:49 2 14.00 110.5 11.21 8.84 752.3 0.0 Calhoun 5/20/2015 9:37:49 3 13.83 109.8 11.18 8.81 753.4 0.0 Calhoun 5/20/2015 9:37:19 4 13.78 108.8 11.08 8.81 753.3 0.0 Calhoun 5/20/2015 9:36:20 5 13.57 107.0 10.95 8.75 754.9 0.0 Calhoun 5/20/2015 9:35:38 6 12.99 100.1 10.39 8.62 753.1 0.0 0.022 0.003 Calhoun 5/20/2015 9:34:49 7 12.02 97.0 10.29 8.44 760.3 0.0 Calhoun 5/20/2015 9:33:29 8 10.60 82.8 9.06 8.04 760.6 0.0 Calhoun 5/20/2015 9:32:59 9 8.92 76.4 8.71 7.95 757.1 0.0 Calhoun 5/20/2015 9:32:15 10 8.70 68.9 7.89 7.88 757.7 0.0 Calhoun 5/20/2015 9:31:27 11 8.45 66.9 7.71 7.86 757.8 0.0 Calhoun 5/20/2015 9:30:46 12 8.24 66.6 7.72 7.84 758.5 0.0 0.023 0.010 Calhoun 5/20/2015 9:29:30 13 8.03 60.8 7.09 7.78 757.9 0.0 Calhoun 5/20/2015 9:28:25 14 7.94 55.9 6.53 7.74 757.7 0.0 Calhoun 5/20/2015 9:27:46 15 7.92 52.7 6.15 7.72 758.1 0.0 Calhoun 5/20/2015 9:27:00 16 7.91 51.3 6.00 7.70 759.4 0.0 Calhoun 5/20/2015 9:26:28 17 7.89 50.4 5.89 7.69 759.3 0.0 Calhoun 5/20/2015 9:25:53 18 7.90 49.7 5.80 7.68 759.2 0.0 0.068 0.053 Calhoun 5/20/2015 9:25:16 19 7.91 49.1 5.73 7.67 759.4 0.0 Calhoun 5/20/2015 9:24:44 20 7.87 48.1 5.63 7.66 759.3 0.0 Calhoun 5/20/2015 9:23:56 21 7.87 45.6 5.33 7.64 759.7 0.0 Calhoun 5/20/2015 9:23:03 22 7.91 43.3 5.05 7.62 759.4 0.0 0.090 0.066 149 Calhoun 5/20/2015 9:22:17 23 7.87 41.6 4.86 7.60 761.4 0.0 Calhoun 5/20/2015 9:21:48 24 7.93 40.2 4.69 7.59 760.1 0.0 Cedar 5/20/2015 11:10:00 4.15 0 14.82 108.2 10.78 8.69 818.6 0.0 2.50 1.00 0.030 0.003 0.725 151 Cedar 5/20/2015 11:09:21 1 14.75 108.6 10.83 8.68 818.4 0.0 Cedar 5/20/2015 11:08:11 2 14.66 107.5 10.74 8.69 818.0 0.0 Cedar 5/20/2015 11:07:21 3 14.56 106.4 10.66 8.65 816.2 0.0 Cedar 5/20/2015 11:06:04 4 13.94 94.1 9.55 8.51 821.4 5.7 Cedar 5/20/2015 11:05:03 5 13.32 82.9 8.53 8.34 819.5 0.0 0.029 0.005 Cedar 5/20/2015 11:03:41 6 10.81 52.9 5.76 7.86 819.7 0.0 Cedar 5/20/2015 11:02:07 7 9.51 35.6 4.00 7.73 819.3 0.0 Cedar 5/20/2015 11:00:51 8 8.92 16.6 1.89 7.62 820.6 0.0 Cedar 5/20/2015 10:59:47 9 8.50 3.6 0.42 7.56 821.3 0.0 Cedar 5/20/2015 10:58:19 10 8.17 0.0 0.00 7.52 822.4 0.0 0.086 0.056 Cedar 5/20/2015 10:57:33 11 7.62 0.0 0.00 7.50 829.3 0.0 Cedar 5/20/2015 10:56:38 12 7.14 0.0 0.00 7.47 839.1 1.1 Cedar 5/20/2015 10:55:36 13 6.53 0.0 0.00 7.42 861.3 4.3 Cedar 5/20/2015 10:54:53 14 6.05 0.0 0.00 7.38 881.7 8.1 0.250 0.163 161 Cedar 5/20/2015 10:54:08 15 6.27 0.0 0.00 7.37 877.0 16.1 Diamond 5/18/2015 9:45:00 0 15.19 69.8 6.81 7.89 976.0 3.1 3.10 0.80 0.104 0.010 9.800 254 Diamond 5/18/2015 9:45:55 0.2 15.25 67.3 6.55 7.89 975.3 1.5 Harriet 5/19/2015 10:21:52 5.15 0 13.46 97.3 10.00 8.68 658.5 45.3 1.50 1.30 0.037 0.006 0.624 156 Harriet 5/19/2015 10:21:10 1 13.48 97.5 10.02 8.68 659.0 0.0 Harriet 5/19/2015 10:20:31 2 13.49 97.5 10.02 8.67 658.5 0.0 Harriet 5/19/2015 10:19:38 3 13.47 97.4 10.01 8.65 658.6 0.0 Harriet 5/19/2015 10:18:51 4 13.47 96.9 9.96 8.68 658.2 0.0 Harriet 5/19/2015 10:18:14 5 13.44 96.8 9.96 8.63 659.0 0.0 Harriet 5/19/2015 10:17:04 6 13.40 96.6 9.94 8.66 659.5 0.0 0.030 0.007 Harriet 5/19/2015 10:15:58 7 12.43 86.0 9.05 8.27 657.9 0.0

2015 Water Resources Report - Minneapolis Park Recreation Board Page B7 Date Time Secchi Depth DO pH SpCond TurbSC Chl‐a Pheo‐a Silica TP SRP TKN NO3NO2 Alk Hard SO4 K Ca Mg E. Coli Lake Name MM/DD/YYY HH:MM:SS meters meters Temp °C %DO mg/L units µS/cm NTU mg/M3 mg/M3 mg/L mg/L mg/L mg/L TN mg/L mg/L mg/L mg/L Cl mg/L mg/L mg/L mg/L mg/L mpn/100mL Harriet 5/19/2015 10:15:14 8 9.32 74.7 8.45 8.07 663.7 0.0 Harriet 5/19/2015 10:13:57 9 8.61 70.3 8.09 7.98 663.8 0.0 Harriet 5/19/2015 10:13:02 10 8.38 64.4 7.44 7.92 663.1 0.0 Harriet 5/19/2015 10:12:07 11 8.25 60.7 7.04 7.88 664.5 0.0 Harriet 5/19/2015 10:10:50 12 7.98 52.4 6.12 7.81 665.0 0.0 0.094 0.082 Harriet 5/19/2015 10:10:00 13 7.88 49.3 5.77 7.79 665.1 0.0 Harriet 5/19/2015 10:09:18 14 7.87 47.4 5.55 7.77 664.7 0.0 Harriet 5/19/2015 10:08:23 15 7.83 43.3 5.08 7.74 665.7 0.0 0.110 0.091 Harriet 5/19/2015 10:07:27 16 7.79 41.6 4.88 7.69 665.9 0.0 Harriet 5/19/2015 10:06:16 17 7.72 33.1 3.89 7.65 667.0 0.0 Harriet 5/19/2015 10:04:52 18 7.69 28.5 3.36 7.63 667.2 0.0 Harriet 5/19/2015 10:03:13 19 7.67 27.3 3.21 7.62 667.4 0.0 Harriet 5/19/2015 10:01:55 20 7.66 25.4 2.99 7.60 668.7 0.0 0.151 0.134 129 Harriet 5/19/2015 10:00:46 21 7.63 21.2 2.50 7.58 668.8 0.0 Harriet 5/19/2015 9:59:48 22 7.63 19.1 2.25 7.57 668.4 0.0 Harriet 5/19/2015 9:58:48 23 7.61 17.7 2.09 7.57 669.3 0.0 Harriet 5/19/2015 9:57:34 24 7.59 13.6 1.60 7.58 671.9 0.0 Hiawatha 5/21/2015 11:27:20 1.95 0 15.19 112.9 11.07 8.31 887.6 1.8 16.50 2.50 0.062 0.010 1.011 178 Hiawatha 5/21/2015 11:26:29 1 14.98 113.2 11.14 8.31 886.9 1.8 Hiawatha 5/21/2015 11:25:10 2 14.79 113.5 11.22 8.28 886.6 1.9 Hiawatha 5/21/2015 11:23:37 3 14.09 90.1 9.04 8.01 913.4 2.1 Hiawatha 5/21/2015 11:22:50 4 13.80 90.1 9.10 7.99 923.5 5.8 0.065 0.011 185 Isles 5/20/2015 10:09:57 3.31 0 14.73 109.6 10.94 8.85 734.0 0.0 0.80 <0.5 0.028 0.004 0.539 159 Isles 5/20/2015 10:09:19 1 14.71 109.7 10.96 8.87 734.0 0.0 Isles 5/20/2015 10:08:34 2 14.65 109.6 10.96 8.86 733.4 0.0 Isles 5/20/2015 10:07:53 3 14.60 109.1 10.92 8.86 733.7 0.0 Isles 5/20/2015 10:06:56 4 14.24 99.6 10.05 8.71 734.4 0.0 Isles 5/20/2015 10:05:22 5 12.88 57.3 5.95 7.85 754.3 0.0 0.030 0.011 Isles 5/20/2015 10:04:33 6 10.74 22.5 2.46 7.60 766.4 0.0 Isles 5/20/2015 10:02:35 7 10.07 5.4 0.60 7.54 767.7 0.0 Isles 5/20/2015 10:01:15 8 9.57 0.0 0.00 7.51 769.7 3.8 0.084 0.056 156 Isles 5/20/2015 10:00:35 9 9.22 0.3 0.03 7.50 776.3 11.6 Loring 5/18/2015 11:32:51 1.95 0 16.83 82.8 7.78 8.06 1734 0 3.70 3.20 0.153 0.076 1.08 513 Loring 5/18/2015 11:31:42 1 16.87 82.5 7.75 8.04 1732 0 Loring 5/18/2015 11:30:57 2 16.86 82.1 7.71 8.05 1731 0 Loring 5/18/2015 11:30:10 3 16.83 81.9 7.69 8.09 1732 0 Loring 5/18/2015 11:29:02 4 16.59 80.6 7.61 8.03 1732 0 0.147 0.079 537 Loring 5/18/2015 11:27:59 4.4 16.5 83.6 7.92 8.08 1730 1809 Nokomis 5/21/2015 10:06:33 1.75 0 15.23 105.0 10.29 8.77 545.1 51.6 6.60 5.90 0.025 0.003 0.628 107 Nokomis 5/21/2015 10:05:56 1 15.15 104.6 10.27 8.78 545.0 43.4 Nokomis 5/21/2015 10:05:08 2 15.01 103.2 10.16 8.77 545.3 26.4 Nokomis 5/21/2015 10:04:24 3 14.98 102.8 10.13 8.75 545.7 16.3 Nokomis 5/21/2015 10:02:59 4 14.50 77.6 7.73 8.42 547.5 9.8 0.056 <0.003 Nokomis 5/21/2015 10:02:15 5 14.43 80.6 8.04 8.45 547.4 7.6 Nokomis 5/21/2015 10:01:27 6 14.41 78.1 7.80 8.41 547.5 7.7 Nokomis 5/21/2015 10:00:05 7 14.38 72.1 7.19 8.27 548.2 14.1 0.086 0.003 93 Nokomis 5/21/2015 9:58:40 7.9 14.42 41.6 4.15 7.80 548.0 25.1 Powderhorn 5/18/2015 10:20:30 0.40 0 16.86 86.3 8.14 7.66 711.0 17.8 24.80 22.60 0.153 0.003 1.507 178 Powderhorn 5/18/2015 10:20:01 1 16.86 85.7 8.08 7.73 711.2 31.3 Powderhorn 5/18/2015 10:19:27 2 16.84 85.8 8.09 7.65 711.4 255.8 Powderhorn 5/18/2015 10:18:50 3 16.85 87.5 8.25 7.68 711.0 277.2 Powderhorn 5/18/2015 10:18:19 4 16.85 86.7 8.17 7.67 710.7 303.5 0.159 0.003 Powderhorn 5/18/2015 10:17:46 5 16.84 86.5 8.16 7.71 710.6 16.0 Powderhorn 5/18/2015 10:17:10 6 16.83 86.8 8.19 7.79 711.0 16.9 0.147 0.003 215 Wirth 5/19/2015 11:22:27 3.86 0 14.56 91 9.12 8.36 973.2 0 2.00 1.30 0.028 0.003 <0.500 200 Wirth 5/19/2015 11:22:00 1 14.54 90.2 9.05 8.33 973.6 0 Wirth 5/19/2015 11:20:36 2 14.47 89.5 8.98 8.32 974.2 0 Wirth 5/19/2015 11:19:44 3 14.4 88.3 8.88 8.31 974.4 0

2015 Water Resources Report - Minneapolis Park Recreation Board Page B8 Date Time Secchi Depth DO pH SpCond TurbSC Chl‐a Pheo‐a Silica TP SRP TKN NO3NO2 Alk Hard SO4 K Ca Mg E. Coli Lake Name MM/DD/YYY HH:MM:SS meters meters Temp °C %DO mg/L units µS/cm NTU mg/M3 mg/M3 mg/L mg/L mg/L mg/L TN mg/L mg/L mg/L mg/L Cl mg/L mg/L mg/L mg/L mg/L mpn/100mL Wirth 5/19/2015 11:18:46 4 13.45 60.2 6.19 7.97 986 0 0.035 0.003 Wirth 5/19/2015 11:17:44 5 10.93 6.3 0.69 7.62 994.8 0 Wirth 5/19/2015 11:16:29 6 9.57 0 0 7.54 1012 2.7 Wirth 5/19/2015 11:15:44 7 8.34 0 0 7.38 1130 24.2 0.246 0.031 205 Calhoun 6/1/2015 12:36:42 5.21 0 17.60 115.2 10.82 8.83 731.0 0.0 1.88 0.50 <0.500 0.019 0.003 <0.500 163 Calhoun 6/1/2015 12:36:19 1 17.54 115.8 10.90 8.83 731.5 0.0 Calhoun 6/1/2015 12:35:32 2 17.40 113.4 10.70 8.84 732.8 0.0 Calhoun 6/1/2015 12:34:12 3 17.33 111.8 10.56 8.82 733.2 0.0 Calhoun 6/1/2015 12:33:28 4 16.83 111.3 10.62 8.79 737.1 0.0 Calhoun 6/1/2015 12:32:36 5 15.53 110.3 10.82 8.73 745.3 28.3 Calhoun 6/1/2015 12:31:38 6 13.66 98.2 10.04 8.57 750.0 0.0 0.027 0.003 Calhoun 6/1/2015 12:30:30 7 12.32 80.1 8.43 8.22 749.8 0.0 Calhoun 6/1/2015 12:29:30 8 11.22 71.0 7.67 8.00 753.0 0.0 Calhoun 6/1/2015 12:28:05 9 9.26 54.2 6.12 7.75 755.9 0.0 Calhoun 6/1/2015 12:26:48 10 8.71 53.9 6.18 7.71 753.9 0.0 Calhoun 6/1/2015 12:25:49 11 8.61 50.0 5.74 7.68 755.6 0.0 Calhoun 6/1/2015 12:24:22 12 8.40 55.2 6.37 7.70 754.1 0.0 0.030 0.013 Calhoun 6/1/2015 12:23:15 13 8.19 55.8 6.48 7.68 753.2 0.0 Calhoun 6/1/2015 12:21:58 14 8.07 48.8 5.67 7.64 754.6 0.0 Calhoun 6/1/2015 12:21:02 15 7.99 42.0 4.89 7.58 755.1 0.0 Calhoun 6/1/2015 12:20:04 16 7.97 40.7 4.74 7.57 755.8 0.0 Calhoun 6/1/2015 12:19:02 17 7.95 37.3 4.35 7.54 756.1 0.0 Calhoun 6/1/2015 12:18:00 18 7.92 32.3 3.77 7.50 755.7 0.0 0.086 0.071 Calhoun 6/1/2015 12:17:01 19 7.88 30.2 3.53 7.50 756.0 0.0 Calhoun 6/1/2015 12:15:58 20 7.90 27.7 3.23 7.47 756.8 0.0 Calhoun 6/1/2015 12:15:03 21 7.94 26.5 3.10 7.46 755.7 0.0 Calhoun 6/1/2015 12:14:02 22 7.97 23.9 2.79 7.44 756.2 0.0 0.112 0.086 158 Calhoun 6/1/2015 12:12:21 23 7.84 22.5 2.63 7.42 758.2 0.0 Calhoun 6/1/2015 12:11:04 24 8.12 15.5 1.80 7.41 754.4 0.0 Cedar 6/1/2015 9:50:09 1.92 0 18.16 122.4 11.37 8.92 790.5 3.9 7.66 0.60 0.750 0.021 0.003 0.810 143 Cedar 6/1/2015 9:48:55 1 18.12 122.2 11.35 8.92 790.7 3.7 Cedar 6/1/2015 9:47:51 2 18.08 122.2 11.36 8.89 791.4 3.3 Cedar 6/1/2015 9:47:08 3 17.98 119.4 11.13 8.87 792.5 19.3 Cedar 6/1/2015 9:44:54 4 15.43 84.2 8.28 8.37 830.6 0.0 Cedar 6/1/2015 9:43:36 5 13.33 60.0 6.17 8.07 817.3 0.0 0.022 0.004 Cedar 6/1/2015 9:42:16 6 11.72 36.5 3.89 7.77 816.8 0.0 Cedar 6/1/2015 9:41:01 7 9.97 25.6 2.85 7.64 814.2 1.0 Cedar 6/1/2015 9:39:39 8 9.03 4.4 0.50 7.55 817.8 0.0 Cedar 6/1/2015 9:38:56 9 8.56 0.0 0.00 7.51 818.4 0.0 Cedar 6/1/2015 9:37:43 10 8.17 0.0 0.00 7.50 821.6 0.4 0.115 0.079 Cedar 6/1/2015 9:36:40 11 7.63 0.0 0.00 7.44 826.6 0.5 Cedar 6/1/2015 9:35:40 12 7.17 0.0 0.00 7.41 837.5 2.1 Cedar 6/1/2015 9:34:19 13 6.74 0.0 0.00 7.38 854.1 4.3 Cedar 6/1/2015 9:33:28 14 6.38 0.0 0.00 7.32 867.7 5.9 0.294 0.202 163 Cedar 6/1/2015 9:32:51 15 6.31 0.0 0.00 7.30 870.3 6.7 Cedar 6/1/2015 9:32:12 16 6.44 0.0 0.00 7.27 869.1 6.6 Cedar 6/1/2015 9:31:15 16.2 6.31 0.0 0.00 7.24 871.4 11.7 Diamond 6/4/2015 9:25:43 0 18.97 32.5 2.94 7.70 459.8 14.0 8.35 2.90 3.104 0.128 0.019 1.375 124 Diamond 6/4/2015 9:26:18 0.6 18.95 24.2 2.19 7.56 479.2 42.3 Harriet 6/2/2015 9:39:24 1.95 0 17.63 129.2 12.05 9.10 640.9 5.1 14.98 1.60 <0.500 0.042 0.003 1.151 121 Harriet 6/2/2015 9:38:49 1 17.63 129.1 12.04 9.08 640.9 4.2 Harriet 6/2/2015 9:37:59 2 17.60 129.5 12.08 9.07 641.2 5.7 Harriet 6/2/2015 9:37:22 3 17.48 122.8 11.49 9.02 642.1 2.8 Harriet 6/2/2015 9:37:01 4 16.71 106.4 10.15 8.82 646.0 0.0 Harriet 6/2/2015 9:36:38 5 14.81 92.1 9.12 8.44 657.3 0.0 Harriet 6/2/2015 9:36:04 6 13.55 84.1 8.55 8.26 657.5 0.0 0.038 0.007 Harriet 6/2/2015 9:35:22 7 11.95 64.9 6.85 7.94 663.0 0.0 Harriet 6/2/2015 9:34:56 8 9.96 57.4 6.34 7.76 662.8 0.0

2015 Water Resources Report - Minneapolis Park Recreation Board Page B9 Date Time Secchi Depth DO pH SpCond TurbSC Chl‐a Pheo‐a Silica TP SRP TKN NO3NO2 Alk Hard SO4 K Ca Mg E. Coli Lake Name MM/DD/YYY HH:MM:SS meters meters Temp °C %DO mg/L units µS/cm NTU mg/M3 mg/M3 mg/L mg/L mg/L mg/L TN mg/L mg/L mg/L mg/L Cl mg/L mg/L mg/L mg/L mg/L mpn/100mL Harriet 6/2/2015 9:34:28 9 8.74 49.2 5.60 7.69 662.8 0.0 Harriet 6/2/2015 9:33:57 10 8.49 44.9 5.19 7.65 663.3 0.0 Harriet 6/2/2015 9:33:29 11 8.26 41.3 4.75 7.61 664.1 0.0 Harriet 6/2/2015 9:32:51 12 8.19 38.3 4.41 7.58 665.4 0.0 0.136 0.105 Harriet 6/2/2015 9:32:27 13 8.09 33.7 3.90 7.56 663.1 0.0 Harriet 6/2/2015 9:32:08 14 8.00 31.1 3.60 7.53 666.7 0.0 Harriet 6/2/2015 9:31:37 15 7.97 28.4 3.29 7.51 664.5 0.0 0.138 0.128 Harriet 6/2/2015 9:31:04 16 7.88 19.7 2.29 7.46 665.1 0.0 Harriet 6/2/2015 9:30:36 17 7.78 10.8 1.26 7.42 667.7 0.0 Harriet 6/2/2015 9:30:00 18 7.77 7.0 0.82 7.40 668.3 0.0 Harriet 6/2/2015 9:29:33 19 7.73 4.9 0.57 7.39 670.6 1.8 Harriet 6/2/2015 9:28:55 20 7.78 2.7 0.31 7.37 700.3 6.6 0.289 0.199 131 Hiawatha 6/8/2015 11:27:02 2.80 0 22.12 63.1 5.31 7.71 705.0 43.5 4.18 1.10 2.722 0.076 0.034 0.818 146 Hiawatha 6/8/2015 11:26:20 1 21.73 63.2 5.37 7.73 707.1 0.8 Hiawatha 6/8/2015 11:25:40 2 21.01 46.7 4.02 7.66 709.9 2.6 Hiawatha 6/8/2015 11:25:05 3 19.45 26.6 2.36 7.56 717.3 7.1 Hiawatha 6/8/2015 11:24:22 4 15.08 0.0 0.00 7.42 895.0 10.6 0.194 0.065 153 Hiawatha 6/8/2015 11:23:39 5 13.75 0.0 0.00 7.43 941.6 12.1 Hiawatha 6/8/2015 11:23:07 6 10.76 0.1 0.01 7.48 1073.0 14.2 Hiawatha 6/8/2015 11:22:11 6.5 9.85 0.5 0.05 7.42 1204.0 51.6 Isles 6/1/2015 10:44:15 4.30 0 18.21 129.0 11.97 9.29 682.3 0.0 3.56 0.60 <0.500 0.024 0.003 0.516 158 Isles 6/1/2015 10:43:25 1 18.15 129.3 12.01 9.28 682.0 0.0 Isles 6/1/2015 10:42:49 2 18.08 129.9 12.09 9.29 682.5 0.0 Isles 6/1/2015 10:41:49 3 18.04 126.2 11.75 9.30 681.6 0.0 Isles 6/1/2015 10:41:12 4 15.65 78.9 7.72 8.35 729.4 0.0 Isles 6/1/2015 10:40:44 5 13.54 27.9 2.86 7.69 746.5 0.0 0.037 0.009 Isles 6/1/2015 10:40:11 6 11.66 3.3 0.36 7.53 762.8 0.0 Isles 6/1/2015 10:39:34 7 10.47 0.0 0.00 7.52 763.1 0.0 Isles 6/1/2015 10:38:55 8 9.82 0.0 0.00 7.46 766.3 8.8 0.108 0.048 168 Isles 6/1/2015 10:38:31 9 9.26 0.0 0.00 7.38 776.5 9.1 Loring 6/4/2015 11:35:00 1.50 0 20 71.6 6.32 7.88 1756 2.4 5.16 2.90 8.88 0.140 0.080 0.864 495 Loring 6/4/2015 11:34:11 1 19.91 68.9 6.1 7.87 1762 2.7 Loring 6/4/2015 11:33:19 2 19.86 67 5.93 7.86 1759 1.8 Loring 6/4/2015 11:32:00 3 19.84 65.4 5.79 7.85 1762 1.2 Loring 6/4/2015 11:30:45 4 19.75 55.8 4.95 7.79 1760 0 0.162 0.095 508 Nokomis 6/8/2015 9:37:27 2.70 0 21.24 101.6 8.71 8.49 545.2 165.7 4.21 0.80 <0.500 0.037 <0.003 <0.500 92 Nokomis 6/8/2015 9:36:54 1 21.19 101.4 8.70 8.49 545.2 10.1 Nokomis 6/8/2015 9:35:13 2 20.98 100.5 8.66 8.45 544.4 7.2 Nokomis 6/8/2015 9:34:07 3 20.36 92.6 8.08 8.37 542.7 11.8 Nokomis 6/8/2015 9:33:03 4 19.99 80.5 7.07 8.20 546.6 3.5 0.041 <0.003 Nokomis 6/8/2015 9:31:00 5 18.61 29.5 2.66 7.75 558.7 8.0 Nokomis 6/8/2015 9:29:50 6 16.78 4.6 0.43 7.57 556.4 3.7 Nokomis 6/8/2015 9:28:40 7 14.37 0.1 0.01 7.57 563.8 1.8 0.040 <0.003 104 Nokomis 6/8/2015 9:27:38 8 13.81 0.1 0.01 7.39 580.6 1.3 Powderhorn 6/4/2015 10:24:37 0.54 0 19.68 75.7 6.75 7.43 623.8 22.5 45.40 15.00 2.213 0.098 0.004 1.429 156 Powderhorn 6/4/2015 10:24:04 1 19.68 75.7 6.75 7.43 623.8 17.8 Powderhorn 6/4/2015 10:23:30 2 19.68 75.6 6.74 7.44 623.8 15.7 Powderhorn 6/4/2015 10:22:58 3 19.67 75.1 6.70 7.44 623.9 24.8 Powderhorn 6/4/2015 10:22:18 4 19.67 75.3 6.71 7.45 623.8 16.4 0.132 0.004 Powderhorn 6/4/2015 10:21:39 5 19.67 75.1 6.70 7.45 623.7 15.8 Powderhorn 6/4/2015 10:21:03 6 19.67 74.3 6.63 7.42 623.8 14.5 0.086 0.020 164 Powderhorn 6/4/2015 10:20:14 6.9 19.64 67.0 5.98 7.29 623.5 30.5 Spring 6/4/2015 12:21:22 1.72 0 19.95 15.2 1.33 7.53 2916 0 5.10 2.11 16.6 0.517 0.441 2.67 696 Spring 6/4/2015 12:16:52 1 17.98 0 0 7.22 3125 0.7 Spring 6/4/2015 12:15:26 2 12.98 32.7 3.32 6.75 3982 13 Spring 6/4/2015 12:14:16 3 7.98 0.1 0.02 6.59 4539 20.4 Spring 6/4/2015 12:13:22 4 6.33 0 0.01 6.51 4983 26.5 4.174 3.656 Spring 6/4/2015 12:12:41 5 6.44 0 0.01 6.46 5237 30.4

2015 Water Resources Report - Minneapolis Park Recreation Board Page B10 Date Time Secchi Depth DO pH SpCond TurbSC Chl‐a Pheo‐a Silica TP SRP TKN NO3NO2 Alk Hard SO4 K Ca Mg E. Coli Lake Name MM/DD/YYY HH:MM:SS meters meters Temp °C %DO mg/L units µS/cm NTU mg/M3 mg/M3 mg/L mg/L mg/L mg/L TN mg/L mg/L mg/L mg/L Cl mg/L mg/L mg/L mg/L mg/L mpn/100mL Spring 6/4/2015 12:11:59 6 6.66 0.1 0.02 6.42 5392 34.9 5.710 5.811 1556 Spring 6/4/2015 12:11:11 7 6.95 0.1 0.01 6.39 5486 38.5 Spring 6/4/2015 12:10:23 7.2 7.04 0 0 6.38 5497 357.5 Wirth 6/2/2015 11:28:24 3.90 0 18.88 123.2 11.19 8.48 925.1 0 1.38 0.55 3.14 0.02 0.003 0.51 190.50 Wirth 6/2/2015 11:27:36 1 18.87 123.3 11.2 8.47 925.2 0 Wirth 6/2/2015 11:26:10 2 18.83 123.1 11.19 8.45 924.5 0 Wirth 6/2/2015 11:25:08 3 18.78 122.6 11.16 8.45 925.8 0 Wirth 6/2/2015 11:23:39 4 14.59 86 8.54 8.06 978.7 0.3 0.034 0.003 Wirth 6/2/2015 11:21:08 5 12.07 8 0.84 7.5 996.9 0.6 Wirth 6/2/2015 11:19:51 6 10.3 1.9 0.21 7.4 1020 18.7 Wirth 6/2/2015 11:18:56 7 8.54 0 0 7.17 1160 34.4 0.191 0.062 228 Wirth 6/2/2015 11:17:20 7.4 8.2 0 0 7.1 1284 42.6 Calhoun 6/15/2015 10:48:49 3.91 0 22.47 114.0 9.61 8.76 718.5 0.0 2.16 <0.500 0.014 0.003 0.510 156 Calhoun 6/15/2015 10:48:17 1 22.45 114.3 9.64 8.77 718.6 0.0 Calhoun 6/15/2015 10:47:11 2 22.37 114.1 9.63 8.76 717.9 0.0 Calhoun 6/15/2015 10:46:36 3 21.90 113.3 9.65 8.74 718.1 0.0 Calhoun 6/15/2015 10:45:56 4 21.75 109.0 9.31 8.70 718.1 0.0 Calhoun 6/15/2015 10:45:20 5 18.63 108.8 9.89 8.60 725.3 0.1 Calhoun 6/15/2015 10:44:33 6 14.61 98.2 9.71 8.40 742.6 0.4 0.020 <0.003 Calhoun 6/15/2015 10:43:41 7 13.46 86.2 8.74 8.16 742.4 0.8 Calhoun 6/15/2015 10:42:35 8 11.17 53.8 5.75 7.73 747.4 1.1 Calhoun 6/15/2015 10:41:57 9 9.84 44.1 4.86 7.66 750.7 1.1 Calhoun 6/15/2015 10:41:14 10 9.06 37.9 4.25 7.63 747.9 1.1 Calhoun 6/15/2015 10:40:47 11 8.79 34.5 3.89 7.62 748.8 1.0 Calhoun 6/15/2015 10:39:56 12 8.64 38.5 4.36 7.62 745.9 1.0 0.037 0.020 Calhoun 6/15/2015 10:39:02 13 8.40 42.5 4.84 7.62 745.9 0.9 Calhoun 6/15/2015 10:38:23 14 8.27 36.4 4.16 7.60 744.8 0.8 Calhoun 6/15/2015 10:37:09 15 8.14 28.6 3.28 7.57 747.4 0.7 Calhoun 6/15/2015 10:35:48 16 8.02 19.0 2.19 7.55 747.3 0.6 Calhoun 6/15/2015 10:35:03 17 8.00 15.1 1.73 7.54 749.0 0.5 Calhoun 6/15/2015 10:34:10 18 7.98 10.3 1.19 7.54 749.0 0.4 0.124 0.090 Calhoun 6/15/2015 10:33:32 19 7.96 6.5 0.75 7.54 749.5 0.3 Calhoun 6/15/2015 10:33:02 20 7.95 5.2 0.60 7.55 751.2 0.3 Calhoun 6/15/2015 10:31:52 21 7.92 0.0 0.00 7.56 751.2 0.2 Calhoun 6/15/2015 10:31:20 22 7.98 0.0 0.00 7.58 751.9 0.1 0.159 0.133 156 Calhoun 6/15/2015 10:30:44 23 7.95 0.0 0.00 7.59 752.0 0.1 Calhoun 6/15/2015 10:30:02 24 8.10 0.0 0.00 7.63 749.3 0.1 Cedar 6/15/2015 9:45:06 2.44 0 22.97 118.0 9.85 8.65 765.9 0.3 3.36 0.80 0.024 <0.003 0.666 154 Cedar 6/15/2015 9:44:35 1 22.85 118.4 9.90 8.64 766.6 0.1 Cedar 6/15/2015 9:43:49 2 22.64 119.7 10.05 8.65 765.9 0.0 Cedar 6/15/2015 9:42:16 3 19.89 99.3 8.80 8.39 789.9 0.1 Cedar 6/15/2015 9:41:19 4 17.49 84.3 7.84 8.14 807.8 0.7 Cedar 6/15/2015 9:40:02 5 14.04 45.7 4.57 7.73 813.0 1.8 0.025 <0.003 Cedar 6/15/2015 9:39:11 6 11.90 19.8 2.08 7.57 811.0 2.4 Cedar 6/15/2015 9:38:21 7 10.44 3.9 0.42 7.50 812.5 2.7 Cedar 6/15/2015 9:37:38 8 9.34 0.0 0.00 7.47 809.8 3.1 Cedar 6/15/2015 9:36:42 9 8.57 0.0 0.00 7.44 812.3 3.8 Cedar 6/15/2015 9:36:16 10 8.18 0.0 0.00 7.41 817.0 3.9 0.146 0.103 Cedar 6/15/2015 9:35:29 11 7.86 0.0 0.00 7.40 819.8 4.4 Cedar 6/15/2015 9:34:45 12 7.30 0.0 0.00 7.37 832.8 5.4 Cedar 6/15/2015 9:34:03 13 6.91 0.0 0.00 7.33 848.9 6.5 Cedar 6/15/2015 9:33:24 14 6.71 0.0 0.00 7.32 857.5 7.6 0.283 0.206 161 Cedar 6/15/2015 9:32:45 15 6.94 0.0 0.00 7.32 860.7 9.1 Diamond 6/16/2015 9:45:35 0 21.45 49.3 4.28 7.46 636.2 1.7 9.10 8.75 0.173 0.043 1.000 264 Diamond 6/16/2015 9:44:47 0.4 21.00 21.2 1.85 7.44 639.2 1.6 Harriet 6/18/2015 10:26:19 2.43 0 21.95 112.6 9.61 8.83 637.4 0.0 6.93 0.70 0.031 0.006 <0.500 139 Harriet 6/18/2015 10:25:46 1 21.92 112.1 9.58 8.82 637.4 0.0 Harriet 6/18/2015 10:25:05 2 21.93 112.8 9.64 8.81 637.0 0.0

2015 Water Resources Report - Minneapolis Park Recreation Board Page B11 Date Time Secchi Depth DO pH SpCond TurbSC Chl‐a Pheo‐a Silica TP SRP TKN NO3NO2 Alk Hard SO4 K Ca Mg E. Coli Lake Name MM/DD/YYY HH:MM:SS meters meters Temp °C %DO mg/L units µS/cm NTU mg/M3 mg/M3 mg/L mg/L mg/L mg/L TN mg/L mg/L mg/L mg/L Cl mg/L mg/L mg/L mg/L mg/L mpn/100mL Harriet 6/18/2015 10:24:23 3 21.83 113.0 9.67 8.79 638.0 0.0 Harriet 6/18/2015 10:23:29 4 20.82 101.3 8.84 8.58 643.8 0.0 Harriet 6/18/2015 10:21:51 5 15.81 57.7 5.57 7.90 665.9 0.0 Harriet 6/18/2015 10:20:33 6 13.56 59.0 5.99 7.85 670.6 0.0 0.020 0.009 Harriet 6/18/2015 10:19:09 7 12.12 57.5 6.03 7.78 667.9 0.2 Harriet 6/18/2015 10:17:50 8 10.45 49.8 5.43 7.68 669.5 0.5 Harriet 6/18/2015 10:16:25 9 8.96 35.1 3.96 7.59 670.6 0.7 Harriet 6/18/2015 10:15:18 10 8.67 29.2 3.32 7.56 672.4 0.7 Harriet 6/18/2015 10:14:23 11 8.44 25.9 2.97 7.54 671.9 0.7 Harriet 6/18/2015 10:13:10 12 8.22 20.9 2.41 7.52 673.0 0.7 0.148 0.135 Harriet 6/18/2015 10:11:39 13 8.10 12.6 1.45 7.48 672.1 0.7 Harriet 6/18/2015 10:10:15 14 7.99 3.4 0.40 7.46 672.7 0.8 Harriet 6/18/2015 10:09:15 15 7.93 0.0 0.00 7.44 674.3 0.8 0.201 0.184 Harriet 6/18/2015 10:08:37 16 7.89 0.0 0.00 7.44 673.7 0.8 Harriet 6/18/2015 10:07:40 17 7.85 0.0 0.00 7.44 675.3 0.9 Harriet 6/18/2015 10:06:33 18 7.83 0.0 0.00 7.44 675.1 0.7 Harriet 6/18/2015 10:05:53 19 7.81 0.0 0.00 7.44 676.3 0.7 Harriet 6/18/2015 10:04:50 20 7.78 0.0 0.00 7.44 677.6 0.7 0.257 0.236 135 Harriet 6/18/2015 10:04:08 21 7.77 0.0 0.00 7.45 678.0 0.6 Harriet 6/18/2015 10:03:20 22 7.78 0.0 0.00 7.47 677.8 0.6 Harriet 6/18/2015 10:01:59 23 7.76 0.0 0.00 7.50 678.0 0.6 Harriet 6/18/2015 10:00:56 24 7.82 0.0 0.00 7.55 678.1 0.6 Hiawatha 6/23/2015 11:22:04 1.17 0 23.08 58.3 4.89 7.58 562.1 0.0 11.60 1.30 0.079 0.014 0.957 112 Hiawatha 6/23/2015 11:20:56 1 22.28 52.5 4.47 7.56 559.1 0.0 Hiawatha 6/23/2015 11:20:05 2 22.14 47.4 4.04 7.54 562.4 0.0 Hiawatha 6/23/2015 11:18:56 3 22.00 22.1 1.89 7.49 562.1 0.0 Hiawatha 6/23/2015 11:17:46 4 19.83 0.0 0.00 7.42 663.1 2.4 0.150 0.057 126 Hiawatha 6/23/2015 11:16:11 5 14.32 0.0 0.00 7.34 968.2 5.5 Hiawatha 6/23/2015 11:14:51 6 11.57 0.0 0.00 7.44 1083.0 5.6 Hiawatha 6/23/2015 11:13:45 6.8 9.79 0.0 0.00 7.38 1364.0 8.4 Isles 6/15/2015 10:09:45 3.34 0 22.47 97.8 8.24 9.08 651.3 0.3 1.80 0.80 0.027 0.004 0.621 147 Isles 6/15/2015 10:09:08 1 22.53 97.1 8.17 9.04 651.0 0.7 Isles 6/15/2015 10:08:27 2 22.47 94.4 7.96 8.99 651.3 1.6 Isles 6/15/2015 10:07:23 3 19.63 110.7 9.86 8.77 685.7 4.0 Isles 6/15/2015 10:06:46 4 17.31 89.2 8.33 8.25 716.9 4.9 Isles 6/15/2015 10:06:14 5 14.35 35.1 3.49 7.69 737.9 5.8 0.030 0.006 Isles 6/15/2015 10:05:44 6 12.08 0.0 0.00 7.59 754.5 6.5 Isles 6/15/2015 10:04:49 7 10.90 3.5 0.37 7.61 756.6 8.8 Isles 6/15/2015 10:04:01 8 10.02 0.0 0.00 7.62 757.6 8.1 0.131 0.042 142 Isles 6/15/2015 10:03:28 9 9.47 0.0 0.00 7.61 772.9 7.4 Loring 6/16/2015 11:52:15 0.96 0 23.27 80.2 6.7 7.86 1736 0.9 6.43 2.20 0.144 0.085 0.994 455 Loring 6/16/2015 11:51:22 1 23.33 78.6 6.57 7.85 1735 1.2 Loring 6/16/2015 11:50:16 2 23.05 71.2 5.98 7.79 1735 1.4 Loring 6/16/2015 11:49:24 3 22.79 65.5 5.53 7.74 1732 1.5 Loring 6/16/2015 11:48:38 4 22.36 47.4 4.03 7.61 1734 1.6 0.140 0.094 479 Loring 6/16/2015 11:47:34 4.5 21.93 8.3 0.71 7.36 1770 3 Nokomis 6/23/2015 10:02:43 2.15 0 23.65 98.0 8.12 8.36 539.7 0.0 5.28 0.60 0.032 0.003 0.562 95 Nokomis 6/23/2015 10:00:54 1 23.62 97.8 8.11 8.33 539.3 0.0 Nokomis 6/23/2015 9:59:57 2 23.38 97.2 8.10 8.30 537.8 0.0 Nokomis 6/23/2015 9:58:59 3 23.26 95.5 7.97 8.23 537.7 0.0 Nokomis 6/23/2015 9:57:56 4 22.76 61.0 5.14 7.80 546.6 0.0 0.049 <0.003 Nokomis 6/23/2015 9:56:14 5 21.47 15.4 1.33 7.59 559.9 0.0 Nokomis 6/23/2015 9:54:34 6 17.27 0.0 0.00 7.57 560.9 3.0 Nokomis 6/23/2015 9:53:40 7 14.99 0.0 0.00 7.52 573.3 4.9 0.049 0.003 107 Nokomis 6/23/2015 9:52:53 8 13.28 0.0 0.00 7.34 618.6 6.6 Nokomis 6/23/2015 9:52:01 8.2 13.11 0.0 0.00 7.35 626.8 19.8 Powderhorn 6/16/2015 10:31:25 0.38 0 23.01 73.4 6.19 7.35 610.7 3.2 64.87 27.05 0.154 0.003 1.510 149 Powderhorn 6/16/2015 10:30:46 1 23.01 73.6 6.20 7.36 610.6 3.2

2015 Water Resources Report - Minneapolis Park Recreation Board Page B12 Date Time Secchi Depth DO pH SpCond TurbSC Chl‐a Pheo‐a Silica TP SRP TKN NO3NO2 Alk Hard SO4 K Ca Mg E. Coli Lake Name MM/DD/YYY HH:MM:SS meters meters Temp °C %DO mg/L units µS/cm NTU mg/M3 mg/M3 mg/L mg/L mg/L mg/L TN mg/L mg/L mg/L mg/L Cl mg/L mg/L mg/L mg/L mg/L mpn/100mL Powderhorn 6/16/2015 10:30:01 2 23.00 73.4 6.18 7.36 610.6 3.3 Powderhorn 6/16/2015 10:29:26 3 23.02 73.8 6.22 7.37 610.6 3.3 Powderhorn 6/16/2015 10:28:41 4 23.01 73.3 6.18 7.37 610.5 3.4 0.173 0.003 Powderhorn 6/16/2015 10:26:59 5 22.95 69.7 5.88 7.38 610.6 3.7 Powderhorn 6/16/2015 10:26:13 6 22.89 66.8 5.64 7.39 610.7 3.8 0.159 0.003 165 Powderhorn 6/16/2015 10:25:14 7 22.88 66.3 5.60 7.42 610.5 32.7 Wirth 6/18/2015 11:33:11 4.87 0 22.37 111.7 9.45 8.29 892.4 0 1.80 <0.500 0.027 0.004 0.755 192 Wirth 6/18/2015 11:32:21 1 22.21 110.4 9.37 8.26 891.9 0 Wirth 6/18/2015 11:31:40 2 22.07 110.3 9.39 8.24 889.7 0 Wirth 6/18/2015 11:30:31 3 20.95 60 5.21 7.72 931.6 0 Wirth 6/18/2015 11:28:37 4 16.84 50.5 4.77 7.73 989.5 0.3 0.030 0.009 Wirth 6/18/2015 11:26:56 5 13.6 19.7 2 7.57 1015 5.2 Wirth 6/18/2015 11:25:35 6 11.97 0 0 7.44 1024 7.5 Wirth 6/18/2015 11:24:29 7 9.06 0 0 7.2 1211 20.3 0.315 0.046 221 Wirth 6/18/2015 11:23:15 7.5 8.46 0 0 7.01 1615 56.8 Calhoun 7/7/2015 11:26:10 3.25 0 22.42 103.6 8.83 8.60 0.0 0.0 1.72 0.50 0.507 0.016 0.002 <0.500 <0.500 <0.030 106 132 150 8.16 4.2 38 13 Calhoun 7/7/2015 11:25:12 1 23.20 103.2 8.65 8.59 696.5 0.0 Calhoun 7/7/2015 11:24:15 2 23.19 103.1 8.64 8.57 695.6 0.0 Calhoun 7/7/2015 11:23:26 3 23.17 102.6 8.59 8.55 694.9 0.0 Calhoun 7/7/2015 11:22:41 4 23.12 102.2 8.57 8.50 693.7 0.0 Calhoun 7/7/2015 11:22:01 5 22.89 100.7 8.49 8.41 694.5 0.0 Calhoun 7/7/2015 11:21:19 6 17.97 92.9 8.65 8.12 742.2 0.0 0.020 0.002 Calhoun 7/7/2015 11:20:24 7 14.72 64.9 6.46 7.78 748.2 0.0 Calhoun 7/7/2015 11:19:30 8 11.74 27.6 2.93 7.57 751.3 0.2 Calhoun 7/7/2015 11:18:29 9 10.58 16.4 1.80 7.54 753.6 0.3 Calhoun 7/7/2015 11:16:16 10 9.77 9.6 1.07 7.52 753.9 0.6 Calhoun 7/7/2015 11:15:37 11 9.05 10.1 1.14 7.52 753.8 0.6 Calhoun 7/7/2015 11:14:58 12 8.85 13.2 1.50 7.53 751.3 0.6 0.027 0.015 Calhoun 7/7/2015 11:14:29 13 8.63 13.5 1.54 7.53 752.5 0.6 Calhoun 7/7/2015 11:13:49 14 8.41 17.8 2.04 7.54 751.1 0.5 Calhoun 7/7/2015 11:13:16 15 8.29 13.8 1.59 7.53 751.3 0.5 Calhoun 7/7/2015 11:12:37 16 8.10 0.0 0.00 7.51 751.7 0.5 Calhoun 7/7/2015 11:11:55 17 8.02 0.0 0.00 7.52 753.0 0.5 Calhoun 7/7/2015 11:11:18 18 7.98 0.0 0.00 7.52 753.2 0.5 0.120 0.100 Calhoun 7/7/2015 11:10:26 19 7.94 0.0 0.00 7.53 754.7 0.6 Calhoun 7/7/2015 11:09:43 20 7.91 0.0 0.00 7.55 755.9 0.5 Calhoun 7/7/2015 11:08:47 21 7.89 0.0 0.00 7.57 757.1 0.5 Calhoun 7/7/2015 11:07:31 22 7.92 0.0 0.00 7.61 757.2 0.3 0.155 0.146 152 7.77 Calhoun 7/7/2015 11:07:07 23 7.93 0.0 0.00 7.65 758.1 0.2 Calhoun 7/7/2015 11:06:30 24 7.92 0.0 0.00 7.65 757.7 0.0 Cedar 7/7/2015 9:49:55 1.45 0 23.26 102.6 8.59 8.47 710.6 0.0 5.97 0.70 1.403 0.018 0.008 0.612 0.651 <0.030 115 160 147 12.50 4.1 42 16 Cedar 7/7/2015 9:48:57 1 23.47 102.0 8.50 8.42 734.8 0.0 Cedar 7/7/2015 9:48:09 2 23.40 101.7 8.48 8.33 733.9 0.0 Cedar 7/7/2015 9:47:26 3 23.32 100.2 8.38 8.20 733.2 0.0 Cedar 7/7/2015 9:46:35 4 20.56 59.0 5.20 7.66 796.8 0.0 Cedar 7/7/2015 9:46:00 5 16.45 17.9 1.71 7.49 812.0 0.1 0.015 0.003 Cedar 7/7/2015 9:44:58 6 13.13 0.0 0.00 7.42 814.4 1.6 Cedar 7/7/2015 9:44:17 7 10.85 0.0 0.00 7.40 813.2 2.3 Cedar 7/7/2015 9:43:26 8 9.59 0.0 0.00 7.36 816.0 3.4 Cedar 7/7/2015 9:42:38 9 8.71 0.0 0.00 7.33 819.3 4.3 Cedar 7/7/2015 9:41:49 10 8.28 0.0 0.00 7.31 821.6 2.9 0.153 0.099 Cedar 7/7/2015 9:41:10 11 7.83 0.0 0.00 7.28 829.7 4.9 Cedar 7/7/2015 9:40:34 12 7.38 0.0 0.00 7.26 838.3 6.3 Cedar 7/7/2015 9:40:03 13 7.00 0.0 0.00 7.25 850.1 5.4 Cedar 7/7/2015 9:39:09 14 6.87 0.0 0.00 7.25 855.2 6.5 0.329 0.266 162 11.80 Cedar 7/7/2015 9:38:06 15 6.78 0.0 0.00 7.27 860.9 6.5 Diamond 7/10/2015 9:33:32 0 22.95 58.9 4.94 7.32 412.90 0.0 24.56 8.50 1.224 0.083 0.015 0.681 0.683 <0.030 44 52 97 5.36 Diamond 7/10/2015 9:32:18 0.7 22.26 30.1 2.56 7.34 417.30 0.1

2015 Water Resources Report - Minneapolis Park Recreation Board Page B13 Date Time Secchi Depth DO pH SpCond TurbSC Chl‐a Pheo‐a Silica TP SRP TKN NO3NO2 Alk Hard SO4 K Ca Mg E. Coli Lake Name MM/DD/YYY HH:MM:SS meters meters Temp °C %DO mg/L units µS/cm NTU mg/M3 mg/M3 mg/L mg/L mg/L mg/L TN mg/L mg/L mg/L mg/L Cl mg/L mg/L mg/L mg/L mg/L mpn/100mL Harriet 7/8/2015 10:06:55 2.68 0 23.45 105.1 8.75 8.72 610.5 0.0 2.35 <0.500 0.567 0.017 0.002 <0.500 0.539 <0.030 93 116 110 6.73 3.9 31 12 Harriet 7/8/2015 10:06:23 1 23.46 105.0 8.74 8.71 610.4 0.0 Harriet 7/8/2015 10:05:37 2 23.33 104.0 8.68 8.68 610.0 0.0 Harriet 7/8/2015 10:04:37 3 23.27 103.5 8.64 8.63 609.9 0.0 Harriet 7/8/2015 10:03:49 4 23.06 103.4 8.67 8.53 610.3 0.0 Harriet 7/8/2015 10:02:34 5 20.70 64.8 5.68 7.86 639.8 0.0 Harriet 7/8/2015 10:00:59 6 15.10 21.7 2.14 7.54 661.0 0.0 0.025 0.002 Harriet 7/8/2015 9:59:25 7 12.18 30.7 3.22 7.53 658.5 0.0 Harriet 7/8/2015 9:58:15 8 10.86 22.5 2.43 7.48 660.4 0.0 Harriet 7/8/2015 9:56:36 9 9.66 15.3 1.71 7.43 662.9 0.3 Harriet 7/8/2015 9:55:37 10 8.83 0.0 0.00 7.40 663.5 0.4 Harriet 7/8/2015 9:54:56 11 8.45 0.0 0.00 7.39 665.1 0.5 Harriet 7/8/2015 9:54:05 12 8.27 0.0 0.00 7.38 663.7 0.5 0.218 0.191 Harriet 7/8/2015 9:53:03 13 8.14 0.0 0.00 7.38 665.1 0.5 Harriet 7/8/2015 9:51:55 14 8.04 0.0 0.00 7.36 665.7 0.5 Harriet 7/8/2015 9:51:18 15 7.96 0.0 0.00 7.37 665.8 0.5 0.249 0.236 Harriet 7/8/2015 9:50:36 16 7.92 0.0 0.00 7.36 667.2 0.5 Harriet 7/8/2015 9:49:50 17 7.87 0.0 0.00 7.35 667.0 0.5 Harriet 7/8/2015 9:49:08 18 7.83 0.0 0.00 7.35 667.5 0.5 Harriet 7/8/2015 9:48:25 19 7.83 0.0 0.00 7.36 668.7 0.5 Harriet 7/8/2015 9:47:46 20 7.83 0.0 0.00 7.36 669.5 0.5 0.318 0.291 113 6.34 Harriet 7/8/2015 9:46:53 21 7.87 0.0 0.00 7.36 668.5 0.4 Harriet 7/8/2015 9:45:58 22 7.86 0.0 0.00 7.38 668.5 0.4 Harriet 7/8/2015 9:45:04 23 7.86 0.0 0.00 7.39 668.5 0.4 Harriet 7/8/2015 9:43:50 24 7.83 0.0 0.00 7.42 671.2 0.3 Hiawatha 7/9/2015 11:07:59 1.74 0 22.93 63.7 5.33 7.61 500.9 0.0 5.40 2.30 4.332 0.069 0.027 0.822 0.908 0.054 92 116 100 6.34 Hiawatha 7/9/2015 11:06:50 1 22.49 59.8 5.06 7.63 501.1 0.1 Hiawatha 7/9/2015 11:05:35 2 22.29 55.7 4.73 7.63 501.8 0.1 Hiawatha 7/9/2015 11:03:43 3 21.99 46.8 3.99 7.65 507.8 0.1 Hiawatha 7/9/2015 11:02:37 4 21.77 56.2 4.82 7.74 519.6 0.0 0.072 0.033 97 6.44 Isles 7/7/2015 10:28:18 2.36 0 23.43 90.2 7.52 8.94 628.2 0.0 6.51 2.30 <0.500 0.022 0.003 0.534 0.629 <0.030 73 96 195 6.88 Isles 7/7/2015 10:27:18 1 23.43 90.2 7.53 8.91 628.2 0.0 Isles 7/7/2015 10:26:10 2 23.40 89.7 7.49 8.83 630.7 0.0 Isles 7/7/2015 10:24:50 3 23.36 87.8 7.34 8.59 635.5 0.0 Isles 7/7/2015 10:23:47 4 21.33 7.2 0.63 7.59 694.5 0.2 Isles 7/7/2015 10:22:56 5 16.50 0.0 0.00 7.50 741.4 1.6 0.033 0.008 Isles 7/7/2015 10:21:59 6 13.34 0.0 0.00 7.47 755.6 2.9 Isles 7/7/2015 10:20:24 7 11.36 0.0 0.00 7.39 759.6 5.7 Isles 7/7/2015 10:18:55 8 10.27 0.0 0.00 7.32 767.1 7.6 0.217 0.154 167 6.88 Isles 7/7/2015 10:17:55 9 9.27 0.0 0.00 7.22 790.3 10.0 Isles 7/7/2015 10:17:08 9.5 9.20 0.0 0.00 7.23 794.2 11.3 Loring 7/15/2015 9:56:42 2.61 0 25.56 41.2 3.28 7.51 1616 0 11.7 3.20 2.8 0.134 0.090 0.836 0.882 <0.030 154 240 452 12.8 Loring 7/15/2015 9:55:59 1 25.5 39.9 3.18 7.5 1617 0 Loring 7/15/2015 9:54:55 2 25.45 37.6 2.99 7.49 1617 0 Loring 7/15/2015 9:53:37 3 25.4 30.1 2.4 7.48 1616 0 Loring 7/15/2015 9:52:51 4 25.17 17.9 1.43 7.45 1617 0 0.144 0.094 463 12.7 Loring 7/15/2015 9:51:43 4.5 24.76 1.8 0.14 7.42 1635 0 Nokomis 7/9/2015 10:01:57 1.94 0 23.86 94.6 7.79 8.25 535.7 0.0 4.71 0.80 2.838 0.022 0.004 0.614 0.629 <0.030 110 120 102 5.87 4.2 43 6 Nokomis 7/9/2015 10:00:12 1 23.85 94.9 7.82 8.22 535.3 0.0 Nokomis 7/9/2015 9:58:21 2 23.72 90.8 7.49 8.13 535.8 0.0 Nokomis 7/9/2015 9:57:23 3 23.66 82.5 6.82 8.03 536.5 0.0 Nokomis 7/9/2015 9:56:11 4 23.53 82.9 6.87 7.99 536.5 0.0 0.026 0.003 Nokomis 7/9/2015 9:55:22 5 23.51 83.3 6.89 7.94 535.7 0.0 Nokomis 7/9/2015 9:53:53 6 21.44 5.2 0.45 7.51 553.3 0.0 Nokomis 7/9/2015 9:52:20 7 15.74 0.0 0.00 7.48 584.6 5.2 0.057 0.014 100 5.09 Nokomis 7/9/2015 9:51:31 8 13.58 0.0 0.00 7.28 629.5 5.2 Powderhorn 7/10/2015 10:37:34 0.47 0 25.79 163.2 12.98 9.01 474.7 1.3 47.80 13.20 2.300 0.096 0.013 1.460 1.520 <0.030 40 48 101 6.29 Powderhorn 7/10/2015 10:36:45 1 24.54 103.5 8.42 7.69 471.9 1.5

2015 Water Resources Report - Minneapolis Park Recreation Board Page B14 Date Time Secchi Depth DO pH SpCond TurbSC Chl‐a Pheo‐a Silica TP SRP TKN NO3NO2 Alk Hard SO4 K Ca Mg E. Coli Lake Name MM/DD/YYY HH:MM:SS meters meters Temp °C %DO mg/L units µS/cm NTU mg/M3 mg/M3 mg/L mg/L mg/L mg/L TN mg/L mg/L mg/L mg/L Cl mg/L mg/L mg/L mg/L mg/L mpn/100mL Powderhorn 7/10/2015 10:34:56 2 23.88 22.1 1.82 6.97 470.9 1.7 Powderhorn 7/10/2015 10:33:05 3 23.77 0.0 0.00 6.93 473.1 2.2 Powderhorn 7/10/2015 10:32:06 4 23.73 0.0 0.00 6.93 475.0 2.6 0.098 0.014 Powderhorn 7/10/2015 10:31:17 5 23.72 0.0 0.00 6.94 476.2 3.0 Powderhorn 7/10/2015 10:30:20 6 23.70 0.0 0.00 6.94 477.5 3.5 Powderhorn 7/10/2015 10:29:34 7 23.57 0.0 0.00 6.92 491.6 16.3 0.147 0.041 101 6.29 Spring 7/15/2015 10:47:04 0.65 0 23.04 21.6 1.8 7.23 1833 4.3 90.3 53.5 16.1 0.316 0.213 1.64 1.70 <0.030 306 580 932 79.4 Spring 7/15/2015 10:45:31 1 19.29 1.3 0.12 6.94 3043 8.7 Spring 7/15/2015 10:44:17 2 13.52 0.9 0.09 6.75 3945 13.5 Spring 7/15/2015 10:43:23 3 9.24 0 0 6.61 4563 16.8 Spring 7/15/2015 10:42:11 4 7.31 0 0 6.55 4947 20.5 4.999 4.876 Spring 7/15/2015 10:41:31 5 6.76 0 0 6.52 5166 22.9 Spring 7/15/2015 10:40:20 6 6.9 0 0 6.5 5362 27.2 5.976 5.272 1484 61.4 Spring 7/15/2015 10:39:05 6.9 7.51 0 0 6.51 5441 117.2 Wirth 7/8/2015 11:12:34 2.79 0 23.47 110.9 9.22 8.4 793.7 0.3 8.53 0.900 3.4 0.017 0.004 <0.500 0.599 <0.030 125 212 179 12.9 2.80 40.0 30.0 Wirth 7/8/2015 11:11:50 1 23.43 112 9.32 8.38 793.3 0.7 Wirth 7/8/2015 11:10:46 2 23.38 112.9 9.41 8.33 792.8 1.3 Wirth 7/8/2015 11:09:23 3 22.69 58 4.9 7.76 815.2 2.6 Wirth 7/8/2015 11:07:38 4 19.94 3.5 0.31 7.5 959.9 5.9 0.034 0.004 Wirth 7/8/2015 11:05:36 5 15.76 0.7 0.06 7.49 1006 13.2 Wirth 7/8/2015 11:04:21 6 13.48 0 0 7.41 1019 21 Wirth 7/8/2015 11:02:55 7 10.43 0 0 7.16 1235 34.9 0.204 0.074 217 8.13 Wirth 7/8/2015 11:02:04 7.5 9.61 0 0 7.04 1580 41.5 Calhoun 7/21/2015 10:27:19 3.63 0 24.68 107.4 8.70 8.60 675.2 0.7 2.28 <0.500 0.016 0.004 <0.500 143 Calhoun 7/21/2015 10:26:24 1 24.67 107.3 8.69 8.59 675.0 1.8 Calhoun 7/21/2015 10:25:43 2 24.64 107.8 8.73 8.57 675.0 2.8 Calhoun 7/21/2015 10:25:03 3 24.61 107.4 8.71 8.54 674.5 3.9 Calhoun 7/21/2015 10:23:56 4 24.53 107.3 8.71 8.47 673.8 6.4 Calhoun 7/21/2015 10:23:04 5 24.49 106.3 8.64 8.33 673.4 9.1 Calhoun 7/21/2015 10:22:17 6 20.89 71.1 6.19 7.81 707.8 12.5 0.019 0.003 Calhoun 7/21/2015 10:21:11 7 15.85 36.4 3.51 7.50 745.4 19.5 Calhoun 7/21/2015 10:20:19 8 12.39 9.5 0.99 7.40 752.0 27.1 Calhoun 7/21/2015 10:19:08 9 10.81 1.8 0.19 7.37 756.7 41.0 Calhoun 7/21/2015 10:18:20 10 10.08 0.0 0.00 7.36 755.2 52.3 Calhoun 7/21/2015 10:16:57 11 9.51 0.4 0.05 7.35 755.2 76.0 Calhoun 7/21/2015 10:15:42 12 9.03 3.7 0.41 7.35 753.5 0.0 0.028 0.021 Calhoun 7/21/2015 10:14:34 13 8.84 0.0 0.00 7.35 753.4 0.1 Calhoun 7/21/2015 10:13:29 14 8.53 0.0 0.00 7.35 753.3 0.2 Calhoun 7/21/2015 10:12:42 15 8.33 0.0 0.00 7.34 754.9 0.2 Calhoun 7/21/2015 10:10:54 16 8.14 0.0 0.00 7.35 754.1 0.4 Calhoun 7/21/2015 10:09:37 17 8.07 0.0 0.00 7.36 755.6 0.5 Calhoun 7/21/2015 10:08:46 18 8.02 0.0 0.00 7.36 756.6 0.5 0.139 0.119 Calhoun 7/21/2015 10:08:05 19 7.96 0.0 0.00 7.37 757.5 0.6 Calhoun 7/21/2015 10:07:25 20 8.02 0.0 0.00 7.38 756.1 0.7 Calhoun 7/21/2015 10:06:34 21 8.06 0.0 0.00 7.39 757.3 0.8 Calhoun 7/21/2015 10:05:42 22 7.99 0.0 0.00 7.41 758.4 1.0 0.171 0.147 147 Calhoun 7/21/2015 10:04:44 23 7.92 0.0 0.00 7.43 759.1 1.7 Calhoun 7/21/2015 10:03:37 24 8.05 0.0 0.00 7.47 758.6 0.7 Cedar 7/21/2015 11:37:30 1.09 0 25.92 121.5 9.62 8.67 700.8 0.0 6.58 0.70 0.017 0.004 0.577 152 Cedar 7/21/2015 11:37:01 1 25.42 121.6 9.71 8.67 698.8 0.0 Cedar 7/21/2015 11:36:01 2 25.24 117.4 9.41 8.57 698.4 0.0 Cedar 7/21/2015 11:35:14 3 24.96 114.3 9.21 8.48 701.5 0.0 Cedar 7/21/2015 11:33:49 4 22.71 36.6 3.08 7.68 745.7 0.0 Cedar 7/21/2015 11:32:43 5 18.14 0.0 0.00 7.50 808.6 0.0 0.032 0.003 Cedar 7/21/2015 11:31:26 6 13.57 0.0 0.00 7.47 816.5 0.5 Cedar 7/21/2015 11:30:15 7 11.23 0.0 0.00 7.42 821.7 1.3 Cedar 7/21/2015 11:29:25 8 9.63 0.0 0.00 7.38 818.6 1.6 Cedar 7/21/2015 11:28:34 9 8.81 0.0 0.00 7.35 821.9 2.0

2015 Water Resources Report - Minneapolis Park Recreation Board Page B15 Date Time Secchi Depth DO pH SpCond TurbSC Chl‐a Pheo‐a Silica TP SRP TKN NO3NO2 Alk Hard SO4 K Ca Mg E. Coli Lake Name MM/DD/YYY HH:MM:SS meters meters Temp °C %DO mg/L units µS/cm NTU mg/M3 mg/M3 mg/L mg/L mg/L mg/L TN mg/L mg/L mg/L mg/L Cl mg/L mg/L mg/L mg/L mg/L mpn/100mL Cedar 7/21/2015 11:27:53 10 8.40 0.0 0.00 7.34 825.4 2.3 0.175 0.142 Cedar 7/21/2015 11:27:11 11 7.93 0.0 0.00 7.31 831.1 2.7 Cedar 7/21/2015 11:26:07 12 7.58 0.0 0.00 7.32 836.9 3.5 Cedar 7/21/2015 11:24:47 13 7.28 0.0 0.00 7.33 846.2 4.4 Cedar 7/21/2015 11:23:54 14 7.14 0.0 0.00 7.33 853.0 5.1 0.356 0.292 143 Cedar 7/21/2015 11:22:53 15 7.06 0.0 0.00 7.36 856.4 5.6 Cedar 7/21/2015 11:22:06 15.6 6.93 0.0 0.00 7.41 861.1 6.9 Diamond 7/22/2015 9:12:24 0 23.90 66.0 5.43 7.56 349.2 0.0 36.20 11.30 0.108 0.007 1.720 92 Diamond 7/22/2015 9:11:32 0.7 23.83 63.7 5.24 7.73 349.2 0.0 Harriet 7/20/2015 9:51:31 1.98 0 25.13 101.7 8.10 8.62 611.0 0.0 1.53 <0.500 0.023 <0.003 <0.500 110 Harriet 7/20/2015 9:50:33 1 25.13 102.1 8.13 8.61 610.2 0.0 Harriet 7/20/2015 9:49:01 2 25.12 101.3 8.08 8.57 610.7 0.0 Harriet 7/20/2015 9:47:58 3 25.03 99.5 7.95 8.51 610.9 0.0 Harriet 7/20/2015 9:46:24 4 24.85 90.8 7.27 8.33 613.1 0.0 Harriet 7/20/2015 9:44:44 5 22.54 57.1 4.78 7.83 625.2 0.0 Harriet 7/20/2015 9:43:03 6 17.15 5.4 0.51 7.52 665.6 0.0 0.034 <0.003 Harriet 7/20/2015 9:41:29 7 12.42 2.6 0.27 7.46 671.3 0.0 Harriet 7/20/2015 9:40:02 8 10.91 1.1 0.11 7.44 670.8 0.0 Harriet 7/20/2015 9:38:22 9 9.96 0.0 0.00 7.42 671.6 0.3 Harriet 7/20/2015 9:37:19 10 9.35 0.0 0.00 7.42 670.7 0.4 Harriet 7/20/2015 9:36:25 11 8.82 0.0 0.00 7.41 673.0 0.4 Harriet 7/20/2015 9:35:35 12 8.64 0.0 0.00 7.41 673.0 0.4 0.193 0.177 Harriet 7/20/2015 9:33:54 13 8.39 0.0 0.00 7.40 674.0 0.5 Harriet 7/20/2015 9:31:41 14 8.29 0.0 0.00 7.40 672.8 0.5 Harriet 7/20/2015 9:30:22 15 8.18 0.0 0.00 7.40 674.3 0.5 0.247 0.239 Harriet 7/20/2015 9:28:31 16 8.08 0.0 0.00 7.40 672.7 0.5 Harriet 7/20/2015 9:26:17 17 8.05 0.0 0.00 7.40 673.9 0.5 Harriet 7/20/2015 9:24:13 18 7.94 0.0 0.00 7.41 676.1 0.5 Harriet 7/20/2015 9:23:08 19 7.93 0.0 0.00 7.42 675.1 0.5 Harriet 7/20/2015 9:21:48 20 7.92 0.0 0.00 7.44 675.6 0.4 0.303 0.294 113 Harriet 7/20/2015 9:20:50 21 7.90 0.0 0.00 7.46 677.0 0.4 Harriet 7/20/2015 9:19:28 22 7.88 0.0 0.00 7.50 676.5 0.3 Harriet 7/20/2015 9:17:49 23 7.94 0.0 0.00 7.56 675.0 0.0 Harriet 7/20/2015 9:16:21 24 7.92 0.0 0.00 7.65 676.4 0.0 Hiawatha 7/23/2015 11:02:08 1.88 0 25.66 118.4 9.42 8.22 538.9 0.0 15.74 1.95 0.066 0.006 0.707 88 Hiawatha 7/23/2015 11:00:52 1 25.33 102.6 8.22 7.98 544.9 0.0 Hiawatha 7/23/2015 10:59:44 2 24.80 76.6 6.20 7.70 554.3 0.0 Hiawatha 7/23/2015 10:58:42 3 24.20 36.5 2.99 7.54 537.3 0.0 Hiawatha 7/23/2015 10:57:26 4 23.59 0.0 0.00 7.50 529.8 3.8 0.129 0.083 89 Hiawatha 7/23/2015 10:56:46 5 19.25 0.0 0.00 7.38 701.0 5.7 Hiawatha 7/23/2015 10:55:41 6 12.96 0.0 0.00 7.42 1154.0 8.9 Hiawatha 7/23/2015 10:54:48 6.3 11.83 0.7 0.07 7.45 1257.0 8.8 Isles 7/21/2015 10:57:32 0.81 0 25.52 115.4 9.21 9.06 591.8 0.0 22.56 1.70 0.044 0.005 0.651 113 Isles 7/21/2015 10:56:40 1 25.21 111.3 8.93 9.02 587.9 0.0 Isles 7/21/2015 10:55:37 2 24.97 102.2 8.24 8.91 591.1 0.0 Isles 7/21/2015 10:54:17 3 24.83 64.8 5.24 8.50 596.9 0.0 Isles 7/21/2015 10:52:10 4 21.73 0.1 0.01 7.53 665.0 0.3 Isles 7/21/2015 10:50:58 5 17.10 0.0 0.00 7.39 738.9 2.6 0.025 0.003 Isles 7/21/2015 10:50:05 6 13.77 0.0 0.00 7.33 760.5 3.6 Isles 7/21/2015 10:49:26 7 12.00 0.0 0.00 7.27 761.4 3.9 Isles 7/21/2015 10:48:49 8 10.62 0.0 0.00 7.22 769.6 4.4 0.175 0.126 115 Isles 7/21/2015 10:47:39 9 9.58 0.0 0.00 7.16 790.3 6.4 Isles 7/21/2015 10:46:46 9.7 9.43 0.0 0.00 7.21 797.5 253.3 Loring 7/22/2015 10:44:18 3.04 0 25.34 43.1 3.44 7.41 1584 0 4.69 1.80 0.118 0.074 0.755 412 Loring 7/22/2015 10:43:36 1 25.08 37.1 2.97 7.38 1581 0 Loring 7/22/2015 10:42:36 2 24.86 33.3 2.68 7.36 1574 0 Loring 7/22/2015 10:41:23 3 24.68 19.8 1.59 7.32 1573 0 Loring 7/22/2015 10:39:48 4 23.25 11.4 0.94 7.3 1510 0 0.123 0.085 365

2015 Water Resources Report - Minneapolis Park Recreation Board Page B16 Date Time Secchi Depth DO pH SpCond TurbSC Chl‐a Pheo‐a Silica TP SRP TKN NO3NO2 Alk Hard SO4 K Ca Mg E. Coli Lake Name MM/DD/YYY HH:MM:SS meters meters Temp °C %DO mg/L units µS/cm NTU mg/M3 mg/M3 mg/L mg/L mg/L mg/L TN mg/L mg/L mg/L mg/L Cl mg/L mg/L mg/L mg/L mg/L mpn/100mL Loring 7/22/2015 10:38:57 4.5 23.01 23 1.92 7.34 1501 623 Nokomis 7/23/2015 10:11:43 0.95 0 26.03 120.3 9.52 8.57 512.7 0.0 10.93 2.50 0.039 0.006 0.785 89 Nokomis 7/23/2015 10:10:43 1 26.00 119.8 9.48 8.53 512.4 0.0 Nokomis 7/23/2015 10:09:32 2 25.72 111.5 8.87 8.37 512.7 0.0 Nokomis 7/23/2015 10:08:41 3 25.64 96.2 7.67 8.13 513.8 0.0 Nokomis 7/23/2015 10:07:38 4 25.03 40.9 3.29 7.63 515.7 0.0 0.031 <0.003 Nokomis 7/23/2015 10:06:46 5 24.72 3.3 0.27 7.51 520.9 1.3 Nokomis 7/23/2015 10:05:48 6 23.45 0.0 0.00 7.52 537.4 2.8 Nokomis 7/23/2015 10:04:57 7 18.27 0.0 0.00 7.51 586.4 3.1 0.054 0.005 93 Nokomis 7/23/2015 10:03:40 8 14.42 0.4 0.04 7.39 638.8 0.6 Powderhorn 7/22/2015 9:53:28 0.35 0 25.41 69.0 5.51 7.44 413.8 0.0 53.45 11.70 0.077 0.006 1.560 101 Powderhorn 7/22/2015 9:52:09 1 25.41 68.5 5.47 7.42 413.5 0.0 Powderhorn 7/22/2015 9:51:28 2 25.41 67.5 5.39 7.42 413.4 0.0 Powderhorn 7/22/2015 9:50:23 3 25.37 64.4 5.15 7.41 413.5 0.0 Powderhorn 7/22/2015 9:49:36 4 25.37 65.3 5.22 7.42 413.2 0.0 0.066 0.005 Powderhorn 7/22/2015 9:48:40 5 25.37 64.6 5.17 7.43 413.3 0.0 Powderhorn 7/22/2015 9:47:44 6 25.35 63.5 5.08 7.44 413.4 0.0 0.067 0.006 101 Powderhorn 7/22/2015 9:46:19 7 25.32 59.6 4.77 7.47 412.8 0.0 Wirth 7/22/2015 11:31:02 2.78 0 25.96 127.3 10.05 8.66 756.9 0 2.76 0.90 0.022 0.004 <0.500 221 Wirth 7/22/2015 11:30:24 1 25.91 127.5 10.08 8.65 757.7 0 Wirth 7/22/2015 11:29:45 2 25.75 124.9 9.91 8.59 758.9 0 Wirth 7/22/2015 11:28:08 3 24.33 71.6 5.82 7.84 812.1 0 Wirth 7/22/2015 11:26:48 4 20.85 7.2 0.62 7.54 931.2 1.9 0.033 0.005 Wirth 7/22/2015 11:25:30 5 16.76 0 0 7.51 1002 4.2 Wirth 7/22/2015 11:24:11 6 13.6 0 0 7.42 1051 13.7 Wirth 7/22/2015 11:23:02 7 11.03 0 0 7.29 1288 22.5 0.398 0.100 165 Calhoun 8/4/2015 10:20:15 2.42 0 24.66 106.9 8.67 8.56 675.2 0.0 3.91 0.70 0.701 0.014 <0.003 <0.500 145 Calhoun 8/4/2015 10:19:26 1 24.64 107.3 8.71 8.55 674.8 0.0 Calhoun 8/4/2015 10:18:40 2 24.63 107.0 8.69 8.53 674.8 0.0 Calhoun 8/4/2015 10:18:06 3 24.56 106.7 8.67 8.51 675.0 0.0 Calhoun 8/4/2015 10:17:25 4 24.49 106.5 8.67 8.48 674.8 0.0 Calhoun 8/4/2015 10:16:29 5 24.49 105.4 8.57 8.39 674.4 0.0 Calhoun 8/4/2015 10:15:15 6 23.24 57.0 4.75 7.88 695.9 0.0 0.017 <0.003 Calhoun 8/4/2015 10:13:29 7 17.19 0.0 0.00 7.35 752.1 0.0 Calhoun 8/4/2015 10:11:58 8 12.71 0.0 0.00 7.30 759.8 0.0 Calhoun 8/4/2015 10:11:16 9 11.03 0.0 0.00 7.28 763.7 0.0 Calhoun 8/4/2015 10:10:26 10 10.18 0.0 0.00 7.27 763.3 0.0 Calhoun 8/4/2015 10:09:47 11 9.73 0.0 0.00 7.27 764.4 0.0 Calhoun 8/4/2015 10:08:51 12 9.12 0.0 0.00 7.26 762.9 0.0 0.046 0.024 Calhoun 8/4/2015 10:07:03 13 8.62 0.0 0.00 7.26 762.3 0.1 Calhoun 8/4/2015 10:06:22 14 8.37 0.0 0.00 7.26 762.7 0.1 Calhoun 8/4/2015 10:05:04 15 8.16 0.0 0.00 7.26 764.4 0.1 Calhoun 8/4/2015 10:03:28 16 8.08 0.0 0.00 7.26 767.0 0.1 Calhoun 8/4/2015 10:02:51 17 8.03 0.0 0.00 7.26 765.7 0.1 Calhoun 8/4/2015 10:01:54 18 8.01 0.0 0.00 7.26 766.3 0.1 0.161 0.145 Calhoun 8/4/2015 10:01:13 19 7.98 0.0 0.00 7.26 767.1 0.1 Calhoun 8/4/2015 9:59:57 20 7.96 0.0 0.00 7.27 766.9 0.1 Calhoun 8/4/2015 9:59:17 21 7.94 0.0 0.00 7.27 767.3 0.1 Calhoun 8/4/2015 9:58:18 22 7.94 0.0 0.00 7.28 767.9 0.1 0.199 0.178 154 Calhoun 8/4/2015 9:57:34 23 7.96 0.0 0.00 7.29 767.6 0.1 Calhoun 8/4/2015 9:53:48 24 7.92 0.0 0.00 7.44 768.8 0.0 Cedar 8/4/2015 11:37:58 1.01 0 25.54 111.8 8.92 8.51 692.4 0.0 11.44 1.40 0.959 0.026 0.002 0.688 149 Cedar 8/4/2015 11:37:31 1 25.45 111.3 8.89 8.47 691.9 0.0 Cedar 8/4/2015 11:36:41 2 25.30 107.4 8.60 8.41 692.1 0.0 Cedar 8/4/2015 11:35:32 3 25.13 97.9 7.87 8.21 693.5 0.3 Cedar 8/4/2015 11:34:47 4 24.61 69.4 5.63 7.87 698.8 0.7 Cedar 8/4/2015 11:32:56 5 17.69 0.6 0.06 7.38 825.1 1.7 0.035 0.002 Cedar 8/4/2015 11:32:09 6 13.79 0.0 0.00 7.34 829.0 2.1

2015 Water Resources Report - Minneapolis Park Recreation Board Page B17 Date Time Secchi Depth DO pH SpCond TurbSC Chl‐a Pheo‐a Silica TP SRP TKN NO3NO2 Alk Hard SO4 K Ca Mg E. Coli Lake Name MM/DD/YYY HH:MM:SS meters meters Temp °C %DO mg/L units µS/cm NTU mg/M3 mg/M3 mg/L mg/L mg/L mg/L TN mg/L mg/L mg/L mg/L Cl mg/L mg/L mg/L mg/L mg/L mpn/100mL Cedar 8/4/2015 11:31:28 7 11.31 0.0 0.00 7.32 828.5 2.3 Cedar 8/4/2015 11:30:31 8 10.09 0.0 0.00 7.28 828.1 2.7 Cedar 8/4/2015 11:29:40 9 9.00 0.0 0.00 7.24 832.5 3.1 Cedar 8/4/2015 11:28:46 10 8.37 0.0 0.00 7.22 840.6 3.4 0.222 0.187 Cedar 8/4/2015 11:27:59 11 8.01 0.0 0.00 7.22 844.5 3.7 Cedar 8/4/2015 11:27:23 12 7.74 0.0 0.00 7.22 848.0 4.0 Cedar 8/4/2015 11:26:46 13 7.37 0.0 0.00 7.22 856.4 4.0 Cedar 8/4/2015 11:26:08 14 7.06 0.0 0.00 7.23 868.2 3.9 0.423 0.374 159 Cedar 8/4/2015 11:25:22 15 6.98 0.0 0.00 7.28 870.5 3.3 Cedar 8/4/2015 11:24:19 16 7.10 0.0 0.00 7.39 868.9 1.5 Diamond 8/5/2015 9:35:18 0 23.73 61.7 5.12 7.66 328.1 0.0 24.28 9.70 1.993 0.127 0.006 1.280 81 Diamond 8/5/2015 9:34:37 0.6 23.24 37.1 3.10 7.76 328.8 0.0 Harriet 8/3/2015 9:41:27 2.07 0 24.99 98.9 7.94 8.61 611.3 0.0 5.59 1.10 0.614 0.018 <0.003 <0.500 135 Harriet 8/3/2015 9:40:50 1 25.00 99.1 7.95 8.58 610.9 0.0 Harriet 8/3/2015 9:40:15 2 24.97 98.7 7.93 8.54 611.0 0.0 Harriet 8/3/2015 9:39:37 3 24.87 97.9 7.88 8.46 611.6 0.0 Harriet 8/3/2015 9:38:49 4 24.52 96.6 7.83 8.32 613.3 0.0 Harriet 8/3/2015 9:37:47 5 23.85 58.6 4.80 7.87 621.4 0.0 Harriet 8/3/2015 9:37:02 6 19.55 0.0 0.00 7.49 662.0 0.0 0.026 0.003 Harriet 8/3/2015 9:36:12 7 13.89 0.0 0.00 7.39 670.3 0.2 Harriet 8/3/2015 9:35:27 8 10.87 0.0 0.00 7.37 672.6 0.4 Harriet 8/3/2015 9:34:59 9 9.78 0.0 0.00 7.35 672.5 0.4 Harriet 8/3/2015 9:34:31 10 9.22 0.0 0.00 7.34 672.3 0.5 Harriet 8/3/2015 9:33:55 11 8.86 0.0 0.00 7.34 673.5 0.5 Harriet 8/3/2015 9:33:16 12 8.62 0.0 0.00 7.33 672.9 0.5 0.245 0.206 Harriet 8/3/2015 9:32:47 13 8.40 0.0 0.00 7.32 674.3 0.5 Harriet 8/3/2015 9:32:10 14 8.30 0.0 0.00 7.32 674.2 0.5 Harriet 8/3/2015 9:31:23 15 8.23 0.0 0.00 7.32 674.3 0.5 0.276 0.268 Harriet 8/3/2015 9:30:49 16 8.13 0.0 0.00 7.31 674.6 0.5 Harriet 8/3/2015 9:30:08 17 8.09 0.0 0.00 7.31 676.9 0.6 Harriet 8/3/2015 9:29:35 18 8.04 0.0 0.00 7.31 677.0 0.6 Harriet 8/3/2015 9:29:00 19 8.00 0.0 0.00 7.31 676.3 0.6 Harriet 8/3/2015 9:28:26 20 7.97 0.0 0.00 7.32 676.9 0.6 0.354 0.334 131 Harriet 8/3/2015 9:27:58 21 8.03 0.0 0.00 7.32 676.5 0.6 Harriet 8/3/2015 9:27:28 22 7.98 0.0 0.00 7.34 677.2 0.7 Harriet 8/3/2015 9:26:38 23 8.17 0.0 0.00 7.36 675.0 0.2 Harriet 8/3/2015 9:25:38 24 8.18 0.0 0.00 7.39 672.9 0.0 Hiawatha 8/6/2015 10:42:33 1.50 0 24.25 95.1 7.75 8.02 537.0 0.0 7.33 1.40 3.673 0.060 0.006 0.785 97 Hiawatha 8/6/2015 10:41:59 1 24.26 95.4 7.77 8.00 536.6 0.0 Hiawatha 8/6/2015 10:40:50 2 24.25 92.9 7.57 7.92 536.4 0.0 Hiawatha 8/6/2015 10:39:21 3 23.96 72.8 5.96 7.66 551.4 0.0 Hiawatha 8/6/2015 10:37:57 4 23.53 12.8 1.06 7.49 540.7 0.0 0.100 0.026 99 Hiawatha 8/6/2015 10:36:43 5 20.65 0.0 0.00 7.40 688.2 0.4 Hiawatha 8/6/2015 10:35:30 6 13.35 0.0 0.00 7.32 1263.0 4.4 Hiawatha 8/6/2015 10:34:12 7 10.58 0.0 0.00 7.27 1575.0 395.8 Isles 8/4/2015 11:02:07 0.84 0 25.29 104.5 8.38 8.86 581.9 0.0 21.58 1.90 <0.500 0.034 <0.003 0.986 116 Isles 8/4/2015 11:01:18 1 24.93 101.2 8.17 8.83 576.1 0.0 Isles 8/4/2015 11:00:00 2 24.86 95.0 7.68 8.73 577.4 0.0 Isles 8/4/2015 10:58:55 3 24.80 77.5 6.27 8.50 578.9 0.0 Isles 8/4/2015 10:56:42 4 22.65 0.0 0.00 7.45 642.8 0.0 Isles 8/4/2015 10:55:28 5 17.29 0.0 0.00 7.30 747.2 0.0 0.035 <0.003 Isles 8/4/2015 10:53:57 6 14.24 0.0 0.00 7.22 766.1 0.4 Isles 8/4/2015 10:52:10 7 12.11 0.0 0.00 7.16 772.4 1.2 Isles 8/4/2015 10:50:58 8 10.63 0.0 0.00 7.08 784.4 2.0 0.211 0.192 112 Isles 8/4/2015 10:49:28 9 9.72 0.0 0.00 7.03 804.2 6.7 Loring 8/5/2015 11:22:00 1.82 0 26.13 61.1 4.82 7.47 1592 0 2.76 1.30 8.24 0.124 0.063 4.950 383 Loring 8/5/2015 11:21:02 1 25.69 56.7 4.51 7.44 1590 0 Loring 8/5/2015 11:19:41 2 25.55 49.9 3.98 7.41 1590 0

2015 Water Resources Report - Minneapolis Park Recreation Board Page B18 Date Time Secchi Depth DO pH SpCond TurbSC Chl‐a Pheo‐a Silica TP SRP TKN NO3NO2 Alk Hard SO4 K Ca Mg E. Coli Lake Name MM/DD/YYY HH:MM:SS meters meters Temp °C %DO mg/L units µS/cm NTU mg/M3 mg/M3 mg/L mg/L mg/L mg/L TN mg/L mg/L mg/L mg/L Cl mg/L mg/L mg/L mg/L mg/L mpn/100mL Loring 8/5/2015 11:18:12 3 25.37 36.9 2.96 7.37 1589 0 Loring 8/5/2015 11:16:54 4 25.26 29.1 2.34 7.36 1588 0 0.126 0.069 348 Loring 8/5/2015 11:15:44 4.4 25.25 25.7 2.06 7.38 1589 54.3 Nokomis 8/6/2015 9:49:53 0.97 0 25.13 94.5 7.57 8.31 502.1 0.0 10.95 1.20 3.501 0.036 <0.003 0.889 97 Nokomis 8/6/2015 9:49:15 1 25.19 95.4 7.64 8.29 502.0 0.0 Nokomis 8/6/2015 9:47:55 2 25.18 95.7 7.67 8.22 501.7 0.0 Nokomis 8/6/2015 9:46:48 3 25.18 95.0 7.61 8.11 501.8 0.0 Nokomis 8/6/2015 9:45:47 4 24.99 27.2 2.19 7.55 506.4 0.0 0.052 <0.003 Nokomis 8/6/2015 9:43:37 5 24.87 6.6 0.54 7.50 508.8 0.0 Nokomis 8/6/2015 9:42:33 6 24.62 0.2 0.01 7.50 510.1 0.0 Nokomis 8/6/2015 9:41:15 7 19.53 0.0 0.00 7.40 592.2 0.0 0.058 0.007 99 Nokomis 8/6/2015 9:39:51 8 14.90 0.0 0.00 7.20 660.4 6.0 Nokomis 8/6/2015 9:38:44 8.3 14.33 0.1 0.01 7.26 684.9 1.0 Powderhorn 8/5/2015 10:18:49 0.35 0 25.76 86.9 6.93 7.59 383.4 0.0 38.13 7.40 2.467 0.061 <0.003 1.760 100 125 Powderhorn 8/5/2015 10:17:58 1 25.74 86.1 6.87 7.57 383.4 0.0 Powderhorn 8/5/2015 10:17:07 2 25.74 86.1 6.87 7.58 383.2 0.0 Powderhorn 8/5/2015 10:15:49 3 25.74 85.9 6.85 7.60 383.1 0.0 Powderhorn 8/5/2015 10:14:50 4 25.73 85.7 6.84 7.63 383.1 0.0 0.123 0.005 Powderhorn 8/5/2015 10:14:12 5 25.72 85.8 6.85 7.65 382.9 0.0 Powderhorn 8/5/2015 10:13:23 6 25.68 84.6 6.75 7.68 382.8 0.0 0.072 0.003 100 Powderhorn 8/5/2015 10:12:52 7 25.67 85.0 6.79 7.70 383.0 0.0 Spring 8/5/2015 12:20:11 0.72 0 24.79 2.8 0.22 7.18 1976 0 85.1 19.8 16.1 0.3 0.2 1.8 696 Spring 8/5/2015 12:13:06 1 21.49 0 0 6.87 2754 0 Spring 8/5/2015 12:03:04 2 13.61 0.1 0.01 6.7 3969 10.9 Spring 8/5/2015 12:01:54 3 10.1 0 0 6.57 4523 14.3 Spring 8/5/2015 12:00:27 4 7.79 0 0 6.5 4986 18.4 4.811 4.611 Spring 8/5/2015 11:59:10 5 7.22 0 0 6.48 5179 20.9 Spring 8/5/2015 11:56:57 6 7.19 0 0 6.48 5301 25.2 6.616 6.569 1446 Spring 8/5/2015 11:55:59 7.1 7.54 0 0 6.49 5366 26.9 Wirth 8/3/2015 10:49:46 3.30 0 25.45 115.3 9.17 8.58 755.1 0 2.76 <0.500 2.55 0.019 0.002 <0.500 159 Wirth 8/3/2015 10:49:04 1 25.45 115.1 9.16 8.54 754.8 0 Wirth 8/3/2015 10:48:06 2 25.44 114.6 9.12 8.48 754.5 0 Wirth 8/3/2015 10:46:38 3 24.68 35.5 2.86 7.71 772.6 1.3 Wirth 8/3/2015 10:44:29 4 21.54 41.5 3.56 7.54 939.4 4.3 0.045 0.004 Wirth 8/3/2015 10:42:41 5 17.33 2.2 0.21 7.36 999.2 9.5 Wirth 8/3/2015 10:41:11 6 13.32 0 0 7.24 1062 14.9 Wirth 8/3/2015 10:40:10 7 11.15 0 0 7.08 1307 19.4 0.999 0.029 224 Calhoun 8/20/2015 10:10:36 2.89 0 22.62 90.4 7.64 8.47 694.8 0.0 3.26 1.00 0.018 <0.003 <0.500 145 Calhoun 8/20/2015 10:10:15 1 22.64 90.4 7.64 8.46 694.2 0.0 Calhoun 8/20/2015 10:09:40 2 22.63 90.2 7.63 8.44 693.7 0.0 Calhoun 8/20/2015 10:09:03 3 22.64 90.2 7.63 8.40 693.2 0.0 Calhoun 8/20/2015 10:08:15 4 22.62 90.2 7.63 8.33 693.0 0.0 Calhoun 8/20/2015 10:07:48 5 22.59 89.8 7.60 8.27 692.0 0.0 Calhoun 8/20/2015 10:07:12 6 22.50 87.9 7.45 8.14 691.7 0.0 0.020 <0.003 Calhoun 8/20/2015 10:06:35 7 19.70 0.1 0.01 7.56 775.4 0.2 Calhoun 8/20/2015 10:05:58 8 13.77 0.0 0.00 7.51 789.4 0.5 Calhoun 8/20/2015 10:05:17 9 11.38 0.0 0.00 7.48 790.6 0.7 Calhoun 8/20/2015 10:04:38 10 10.13 0.0 0.00 7.46 791.5 1.0 Calhoun 8/20/2015 10:04:07 11 9.53 0.0 0.00 7.47 791.4 1.2 Calhoun 8/20/2015 10:03:28 12 9.13 0.0 0.00 7.47 789.0 1.3 0.041 0.023 Calhoun 8/20/2015 10:02:58 13 8.73 0.0 0.00 7.46 787.4 1.5 Calhoun 8/20/2015 10:02:24 14 8.43 0.0 0.00 7.46 788.3 1.8 Calhoun 8/20/2015 10:01:52 15 8.18 0.0 0.00 7.44 791.2 2.0 Calhoun 8/20/2015 10:01:19 16 8.06 0.0 0.00 7.44 791.9 2.6 Calhoun 8/20/2015 10:00:54 17 8.02 0.0 0.00 7.44 792.4 2.7 Calhoun 8/20/2015 10:00:23 18 7.99 0.0 0.00 7.45 792.6 2.2 0.174 0.160 Calhoun 8/20/2015 9:59:37 19 7.98 0.0 0.00 7.44 793.1 1.4 Calhoun 8/20/2015 9:58:39 20 7.94 0.0 0.00 7.45 793.5 1.6

2015 Water Resources Report - Minneapolis Park Recreation Board Page B19 Date Time Secchi Depth DO pH SpCond TurbSC Chl‐a Pheo‐a Silica TP SRP TKN NO3NO2 Alk Hard SO4 K Ca Mg E. Coli Lake Name MM/DD/YYY HH:MM:SS meters meters Temp °C %DO mg/L units µS/cm NTU mg/M3 mg/M3 mg/L mg/L mg/L mg/L TN mg/L mg/L mg/L mg/L Cl mg/L mg/L mg/L mg/L mg/L mpn/100mL Calhoun 8/20/2015 9:57:41 21 7.94 0.0 0.00 7.45 794.4 0.0 Calhoun 8/20/2015 9:56:53 22 7.96 0.0 0.00 7.37 793.4 0.3 0.203 0.186 154 Calhoun 8/20/2015 9:55:57 23 7.94 0.0 0.00 7.39 794.5 7.7 Calhoun 8/20/2015 9:54:21 24 8.50 0.0 0.00 7.62 797.0 41.0 Cedar 8/20/2015 11:24:57 0.72 0 22.73 87.4 7.38 8.44 703.2 0.0 23.15 2.80 0.035 0.003 1.370 145 Cedar 8/20/2015 11:24:19 1 22.68 86.7 7.33 8.41 702.7 0.0 Cedar 8/20/2015 11:23:15 2 22.59 84.5 7.16 8.36 702.3 0.0 Cedar 8/20/2015 11:21:57 3 22.50 80.9 6.86 8.27 701.6 0.0 Cedar 8/20/2015 11:20:31 4 22.38 78.2 6.65 8.13 701.4 0.0 Cedar 8/20/2015 11:19:07 5 18.64 0.0 0.00 7.54 847.1 0.0 0.027 0.002 Cedar 8/20/2015 11:17:44 6 14.25 0.0 0.00 7.48 859.1 0.3 Cedar 8/20/2015 11:16:36 7 11.64 0.0 0.00 7.43 857.5 0.7 Cedar 8/20/2015 11:15:47 8 10.19 0.0 0.00 7.40 858.6 1.0 Cedar 8/20/2015 11:14:57 9 8.99 0.0 0.00 7.36 862.1 1.4 Cedar 8/20/2015 11:14:11 10 8.49 0.0 0.00 7.34 868.6 1.7 0.238 0.215 Cedar 8/20/2015 11:13:19 11 7.95 0.0 0.00 7.32 873.8 2.1 Cedar 8/20/2015 11:12:06 12 7.64 0.0 0.00 7.31 880.0 2.9 Cedar 8/20/2015 11:11:24 13 7.43 0.0 0.00 7.31 885.6 3.4 Cedar 8/20/2015 11:10:20 14 7.20 0.0 0.00 7.32 895.5 4.2 0.422 0.382 158 Cedar 8/20/2015 11:09:09 15 7.02 0.0 0.00 7.37 905.2 4.4 Diamond 8/17/2015 13:04:51 0.46 0 24.04 78.5 6.46 8.00 278.0 0.0 72.08 21.20 0.199 0.005 1.190 60 Diamond 8/17/2015 13:04:15 0.6 23.58 31.7 2.63 8.04 267.2 0.0 Harriet 8/19/2015 12:03:03 2.61 0 23.87 93.4 7.65 8.63 607.2 0.0 3.89 1.30 0.019 0.004 <0.500 127 Harriet 8/19/2015 12:02:19 1 23.88 93.4 7.65 8.61 607.3 0.0 Harriet 8/19/2015 12:01:34 2 23.87 93.2 7.63 8.62 607.2 0.0 Harriet 8/19/2015 12:00:38 3 23.87 93.5 7.66 8.60 607.0 0.0 Harriet 8/19/2015 11:59:56 4 23.88 91.9 7.52 8.57 607.0 0.0 Harriet 8/19/2015 11:58:57 5 23.85 91.4 7.49 8.52 607.0 0.0 Harriet 8/19/2015 11:56:27 6 20.72 0.2 0.01 7.67 654.2 0.0 0.019 <0.003 Harriet 8/19/2015 11:55:07 7 14.66 0.0 0.00 7.53 672.6 0.0 Harriet 8/19/2015 11:54:06 8 11.59 5.4 0.57 7.51 669.4 0.0 Harriet 8/19/2015 11:53:10 9 10.19 0.0 0.00 7.48 673.2 0.0 Harriet 8/19/2015 11:52:21 10 9.41 0.0 0.00 7.46 672.7 0.0 Harriet 8/19/2015 11:50:58 11 8.93 0.0 0.00 7.44 674.7 0.0 Harriet 8/19/2015 11:50:20 12 8.67 0.0 0.00 7.44 674.8 0.0 0.215 0.183 Harriet 8/19/2015 11:49:28 13 8.38 0.0 0.00 7.43 676.1 0.0 Harriet 8/19/2015 11:48:35 14 8.20 0.0 0.00 7.42 675.8 0.0 Harriet 8/19/2015 11:47:44 15 8.14 0.0 0.00 7.41 676.4 0.0 0.349 0.296 Harriet 8/19/2015 11:46:51 16 8.07 0.0 0.00 7.39 677.3 0.0 Harriet 8/19/2015 11:46:11 17 8.01 0.0 0.00 7.40 677.8 0.0 Harriet 8/19/2015 11:44:51 18 7.99 0.0 0.00 7.40 678.6 0.0 Harriet 8/19/2015 11:44:21 19 7.97 0.0 0.00 7.41 679.0 0.0 Harriet 8/19/2015 11:43:14 20 7.97 0.0 0.00 7.41 679.4 0.0 0.403 0.351 127 Harriet 8/19/2015 11:42:16 21 7.96 0.0 0.00 7.43 679.7 0.0 Harriet 8/19/2015 11:41:28 22 7.95 0.0 0.00 7.44 679.3 0.0 Harriet 8/19/2015 11:40:38 23 7.93 0.0 0.00 7.46 680.6 0.0 Harriet 8/19/2015 11:40:02 24 7.94 0.0 0.00 7.48 681.2 0.0 Hiawatha 8/21/2015 10:56:20 1.76 0 21.40 67.9 5.83 7.69 505.2 0.0 6.39 1.50 0.057 0.016 0.904 82 Hiawatha 8/21/2015 10:55:44 1 21.39 67.9 5.83 7.69 504.8 0.0 Hiawatha 8/21/2015 10:54:31 2 21.29 66.5 5.73 7.67 502.5 0.0 Hiawatha 8/21/2015 10:53:36 3 21.12 63.4 5.47 7.64 503.2 0.0 Hiawatha 8/21/2015 10:52:13 4 20.81 66.1 5.74 7.65 504.0 0.0 0.060 0.017 82 Hiawatha 8/21/2015 10:50:58 5 20.53 48.9 4.27 7.58 525.0 0.0 Hiawatha 8/21/2015 10:48:39 6 17.21 0.0 0.00 7.29 996.0 6.3 Hiawatha 8/21/2015 10:46:58 7 11.65 0.0 0.00 7.22 1556.0 52.6 Isles 8/20/2015 10:45:22 0.39 0 21.90 75.3 6.46 8.66 600.9 0.0 52.07 6.55 0.054 0.004 1.115 122 Isles 8/20/2015 10:44:30 1 21.89 72.8 6.24 8.60 601.3 0.0 Isles 8/20/2015 10:42:57 2 21.80 67.3 5.79 8.43 602.8 0.0

2015 Water Resources Report - Minneapolis Park Recreation Board Page B20 Date Time Secchi Depth DO pH SpCond TurbSC Chl‐a Pheo‐a Silica TP SRP TKN NO3NO2 Alk Hard SO4 K Ca Mg E. Coli Lake Name MM/DD/YYY HH:MM:SS meters meters Temp °C %DO mg/L units µS/cm NTU mg/M3 mg/M3 mg/L mg/L mg/L mg/L TN mg/L mg/L mg/L mg/L Cl mg/L mg/L mg/L mg/L mg/L mpn/100mL Isles 8/20/2015 10:42:09 3 21.74 69.7 6.00 8.38 599.6 0.0 Isles 8/20/2015 10:40:42 4 21.06 26.3 2.29 7.74 644.9 0.0 Isles 8/20/2015 10:39:24 5 17.55 0.0 0.00 7.43 775.2 0.0 0.029 0.003 Isles 8/20/2015 10:38:31 6 14.24 0.0 0.00 7.37 795.4 0.0 Isles 8/20/2015 10:37:06 7 12.02 0.0 0.00 7.30 803.3 0.2 Isles 8/20/2015 10:36:12 8 10.81 0.0 0.00 7.25 812.6 0.7 0.257 0.194 156 Isles 8/20/2015 10:34:53 9 9.97 0.0 0.00 7.22 833.3 4.1 Loring 8/17/2015 11:09:39 1.27 0 25.8 38.3 3.04 7.52 1576 0 7.81 4.00 0.133 0.061 0.726 410 Loring 8/17/2015 11:08:35 1 25.86 36.2 2.87 7.52 1574 0 Loring 8/17/2015 11:06:49 2 25.79 26 2.06 7.54 1577 0 Loring 8/17/2015 11:06:00 3 25.56 17.2 1.37 7.6 1576 0 Loring 8/17/2015 4 0.141 0.069 455 Nokomis 8/21/2015 10:09:54 0.66 0 23.04 95.2 7.92 8.15 480.1 0.0 27.03 4.50 0.052 0.006 0.994 86 Nokomis 8/21/2015 10:09:18 1 22.86 87.4 7.30 8.05 480.4 0.0 Nokomis 8/21/2015 10:08:14 2 22.83 84.4 7.05 7.99 480.3 0.0 Nokomis 8/21/2015 10:07:02 3 22.82 83.7 7.00 7.96 480.0 0.0 Nokomis 8/21/2015 10:06:06 4 22.80 85.0 7.11 7.92 480.1 0.0 0.047 0.005 Nokomis 8/21/2015 10:04:30 5 22.78 83.5 6.99 7.79 480.0 0.0 Nokomis 8/21/2015 10:03:41 6 22.59 81.9 6.87 7.69 481.0 1.0 Nokomis 8/21/2015 10:02:26 7 22.08 2.0 0.17 7.33 495.6 4.4 0.059 0.004 91 Nokomis 8/21/2015 10:01:21 8 15.86 0.0 0.00 6.96 685.9 9.4 Nokomis 8/21/2015 10:00:12 8.3 14.74 0.0 0.00 6.88 733.3 13.1 Powderhorn 8/17/2015 13:47:01 0.41 0 26.56 130.7 10.26 8.74 369.0 0.0 48.86 8.90 0.143 0.007 1.280 82 Powderhorn 8/17/2015 13:45:43 1 26.32 103.9 8.19 7.92 367.4 0.0 Powderhorn 8/17/2015 13:44:09 2 26.08 77.5 6.14 7.49 366.6 0.0 Powderhorn 8/17/2015 13:43:16 3 26.00 73.2 5.81 7.45 367.9 0.0 Powderhorn 8/17/2015 13:42:06 4 25.90 28.3 2.25 7.28 371.9 0.0 0.127 0.008 Powderhorn 8/17/2015 13:41:02 5 25.74 0.1 0.01 7.20 379.0 0.0 Powderhorn 8/17/2015 13:40:19 6 25.65 0.0 0.00 7.22 381.5 0.0 0.234 0.051 86 Powderhorn 8/17/2015 13:39:29 7 25.51 0.2 0.01 7.22 390.1 0.0 Powderhorn 8/17/2015 13:38:48 7.3 25.38 0.6 0.05 7.28 398.2 59.4 Wirth 8/19/2015 10:51:12 1.89 0 23.42 69.7 5.75 8.13 763.7 0 13.71 2.00 0.037 0.004 <0.500 155 Wirth 8/19/2015 10:50:03 1 23.44 67.9 5.6 8.08 764.1 0 Wirth 8/19/2015 10:48:42 2 23.44 68.1 5.62 8.04 763.6 0 Wirth 8/19/2015 10:47:09 3 23.29 62 5.13 7.85 774.1 0 Wirth 8/19/2015 10:45:53 4 20.87 2.7 0.24 7.43 942.9 0 0.050 0.003 Wirth 8/19/2015 10:44:38 5 17.65 0 0 7.31 995.9 0 Wirth 8/19/2015 10:43:37 6 13.61 0 0 7.2 1081 0 Wirth 8/19/2015 10:42:41 7 11.18 0 0 7.03 1348 0 0.431 0.073 182 Calhoun 9/9/2015 10:39:48 3.26 0 23.42 104.6 8.68 8.62 671.3 0.0 1.76 <0.500 <0.500 0.015 0.003 <0.500 130 Calhoun 9/9/2015 10:38:52 1 23.48 104.7 8.68 8.60 671.2 0.0 Calhoun 9/9/2015 10:38:17 2 23.45 104.8 8.69 8.58 671.4 0.0 Calhoun 9/9/2015 10:37:07 3 23.45 105.0 8.70 8.52 670.9 0.0 Calhoun 9/9/2015 10:35:47 4 23.31 104.1 8.66 8.37 672.1 0.4 Calhoun 9/9/2015 10:34:57 5 21.31 83.3 7.20 8.05 675.9 0.0 Calhoun 9/9/2015 10:33:59 6 20.40 63.7 5.60 7.84 678.7 0.0 0.016 <0.003 Calhoun 9/9/2015 10:32:34 7 18.98 27.2 2.47 7.61 685.9 0.0 Calhoun 9/9/2015 10:31:38 8 15.90 0.0 0.00 7.50 732.0 0.0 Calhoun 9/9/2015 10:30:52 9 12.17 0.0 0.00 7.46 759.1 0.1 Calhoun 9/9/2015 10:30:03 10 10.64 0.0 0.00 7.44 759.3 0.2 Calhoun 9/9/2015 10:29:20 11 9.61 0.0 0.00 7.45 759.7 0.2 Calhoun 9/9/2015 10:28:34 12 9.25 0.0 0.00 7.45 756.0 0.2 0.055 0.032 Calhoun 9/9/2015 10:27:57 13 8.54 0.0 0.00 7.44 756.3 0.2 Calhoun 9/9/2015 10:27:23 14 8.32 0.0 0.00 7.43 757.0 0.2 Calhoun 9/9/2015 10:26:39 15 8.22 0.0 0.00 7.43 758.3 0.2 Calhoun 9/9/2015 10:25:59 16 8.14 0.0 0.00 7.43 759.1 0.2 Calhoun 9/9/2015 10:25:15 17 8.12 0.0 0.00 7.43 759.3 0.2 Calhoun 9/9/2015 10:24:21 18 8.08 0.0 0.00 7.45 760.1 0.2 0.174 0.160

2015 Water Resources Report - Minneapolis Park Recreation Board Page B21 Date Time Secchi Depth DO pH SpCond TurbSC Chl‐a Pheo‐a Silica TP SRP TKN NO3NO2 Alk Hard SO4 K Ca Mg E. Coli Lake Name MM/DD/YYY HH:MM:SS meters meters Temp °C %DO mg/L units µS/cm NTU mg/M3 mg/M3 mg/L mg/L mg/L mg/L TN mg/L mg/L mg/L mg/L Cl mg/L mg/L mg/L mg/L mg/L mpn/100mL Calhoun 9/9/2015 10:23:18 19 8.07 0.0 0.00 7.46 759.8 0.2 Calhoun 9/9/2015 10:22:34 20 8.04 0.0 0.00 7.48 759.3 0.3 Calhoun 9/9/2015 10:21:46 21 8.09 0.0 0.00 7.50 759.5 0.4 Calhoun 9/9/2015 10:20:41 22 8.08 0.0 0.00 7.53 759.1 0.8 0.202 0.183 139 Calhoun 9/9/2015 10:19:48 23 8.01 0.0 0.00 7.55 760.5 0.4 Calhoun 9/9/2015 10:18:49 24 8.21 0.0 0.00 7.61 763.9 168.1 Cedar 9/9/2015 11:51:54 0.70 0 23.60 113.2 9.36 8.80 675.4 0.0 8.59 1.70 1.360 0.027 <0.003 1.040 130 Cedar 9/9/2015 11:51:01 1 23.66 112.1 9.26 8.75 674.9 0.0 Cedar 9/9/2015 11:50:13 2 23.64 110.7 9.15 8.68 674.8 0.0 Cedar 9/9/2015 11:49:07 3 23.42 105.0 8.71 8.51 676.3 0.0 Cedar 9/9/2015 11:47:33 4 20.42 16.2 1.43 7.69 692.3 0.0 Cedar 9/9/2015 11:45:58 5 18.90 0.0 0.00 7.58 696.1 0.4 0.023 <0.003 Cedar 9/9/2015 11:45:06 6 15.20 0.0 0.00 7.45 815.7 0.7 Cedar 9/9/2015 11:44:00 7 12.46 0.0 0.00 7.42 826.1 1.0 Cedar 9/9/2015 11:43:00 8 10.05 0.0 0.00 7.40 825.7 1.2 Cedar 9/9/2015 11:40:25 9 9.11 0.0 0.00 7.36 832.1 1.9 Cedar 9/9/2015 11:39:28 10 8.46 0.0 0.00 7.34 838.6 2.3 0.251 0.237 Cedar 9/9/2015 11:38:42 11 8.18 0.0 0.00 7.34 840.9 2.7 Cedar 9/9/2015 11:37:27 12 7.77 0.0 0.00 7.32 847.1 3.6 Cedar 9/9/2015 11:36:40 13 7.49 0.0 0.00 7.32 854.9 4.2 Cedar 9/9/2015 11:35:28 14 7.30 0.0 0.00 7.34 859.9 5.1 0.437 0.427 152 Cedar 9/9/2015 11:34:17 15 7.38 0.0 0.00 7.38 858.8 3.9 Diamond 9/14/2015 9:37:17 0.59 0 17.85 87.3 8.03 7.80 328.0 0.0 23.01 9.42 0.976 0.073 0.003 0.945 114 Diamond 9/14/2015 9:36:24 0.5 17.81 85.7 7.89 7.89 326.3 0.0 Harriet 9/11/2015 9:35:58 2.35 0 22.19 105.4 9.01 8.71 610.6 0.0 3.56 0.90 <0.500 0.013 0.003 <0.500 121 Harriet 9/11/2015 9:35:30 1 22.20 105.2 9.00 8.68 611.0 0.0 Harriet 9/11/2015 9:34:56 2 22.20 105.5 9.02 8.66 610.2 0.0 Harriet 9/11/2015 9:34:01 3 22.17 105.7 9.04 8.61 610.7 0.0 Harriet 9/11/2015 9:32:54 4 22.19 104.7 8.96 8.50 609.8 0.0 Harriet 9/11/2015 9:32:08 5 22.14 103.8 8.88 8.38 610.4 0.0 Harriet 9/11/2015 9:30:57 6 20.21 65.9 5.86 7.84 623.4 0.0 0.018 <0.003 Harriet 9/11/2015 9:29:36 7 18.03 9.7 0.90 7.54 643.0 0.0 Harriet 9/11/2015 9:28:35 8 13.89 0.0 0.00 7.43 670.3 0.0 Harriet 9/11/2015 9:27:24 9 10.67 0.0 0.00 7.38 673.1 0.0 Harriet 9/11/2015 9:26:19 10 9.60 0.0 0.00 7.35 675.1 0.0 Harriet 9/11/2015 9:25:23 11 8.86 0.0 0.00 7.33 676.8 0.0 Harriet 9/11/2015 9:24:41 12 8.54 0.0 0.00 7.32 676.6 0.0 0.271 0.248 Harriet 9/11/2015 9:23:54 13 8.36 0.0 0.00 7.31 677.3 0.0 Harriet 9/11/2015 9:22:41 14 8.27 0.0 0.00 7.30 677.0 0.0 Harriet 9/11/2015 9:21:17 15 8.18 0.0 0.00 7.30 679.1 0.0 0.331 0.330 Harriet 9/11/2015 9:19:56 16 8.13 0.0 0.00 7.30 679.6 0.0 Harriet 9/11/2015 9:19:14 17 8.11 0.0 0.00 7.30 679.7 0.0 Harriet 9/11/2015 9:18:15 18 8.09 0.0 0.00 7.30 680.2 0.0 Harriet 9/11/2015 9:17:21 19 8.05 0.0 0.00 7.30 681.2 0.0 Harriet 9/11/2015 9:15:54 20 8.04 0.0 0.00 7.32 681.3 0.0 0.392 0.375 121 Harriet 9/11/2015 9:14:26 21 8.04 0.0 0.00 7.35 681.1 0.0 Harriet 9/11/2015 9:13:41 22 8.04 0.0 0.00 7.37 681.2 0.0 Harriet 9/11/2015 9:12:23 23 8.02 0.0 0.00 7.40 682.3 0.0 Harriet 9/11/2015 9:11:21 24 8.04 0.0 0.00 7.42 683.3 0.0 Hiawatha 9/15/2015 10:30:25 1.42 0 20.68 93.1 8.11 7.90 552.1 0.0 14.69 3.70 2.460 0.054 0.005 0.886 93 Hiawatha 9/15/2015 10:29:27 1 20.66 92.8 8.09 7.88 552.0 0.0 Hiawatha 9/15/2015 10:28:39 2 20.65 92.3 8.05 7.83 552.0 0.0 Hiawatha 9/15/2015 10:27:36 3 20.50 85.2 7.45 7.75 552.5 0.0 Hiawatha 9/15/2015 10:26:16 4 19.47 48.8 4.36 7.56 555.0 0.2 0.055 0.012 93 Hiawatha 9/15/2015 10:25:20 5 18.91 9.2 0.83 7.48 623.6 0.9 Hiawatha 9/15/2015 10:24:23 6 17.95 0.0 0.00 7.43 753.0 1.7 Hiawatha 9/15/2015 10:23:09 7 15.22 0.0 0.00 7.31 1115.0 17.0 Hiawatha 9/15/2015 10:21:24 7.5 14.76 0.1 0.01 7.41 1194.0 0.4

2015 Water Resources Report - Minneapolis Park Recreation Board Page B22 Date Time Secchi Depth DO pH SpCond TurbSC Chl‐a Pheo‐a Silica TP SRP TKN NO3NO2 Alk Hard SO4 K Ca Mg E. Coli Lake Name MM/DD/YYY HH:MM:SS meters meters Temp °C %DO mg/L units µS/cm NTU mg/M3 mg/M3 mg/L mg/L mg/L mg/L TN mg/L mg/L mg/L mg/L Cl mg/L mg/L mg/L mg/L mg/L mpn/100mL Isles 9/9/2015 11:12:14 0.53 0 23.35 98.7 8.20 9.12 565.1 0.0 17.52 6.30 1.270 0.038 <0.003 1.450 121 Isles 9/9/2015 11:10:14 1 23.39 98.9 8.21 9.09 565.0 0.0 Isles 9/9/2015 11:08:35 2 23.28 94.2 7.84 8.96 565.3 0.0 Isles 9/9/2015 11:05:56 3 19.96 0.0 0.00 7.79 589.6 0.0 Isles 9/9/2015 11:04:38 4 19.34 0.0 0.00 7.73 588.4 0.0 Isles 9/9/2015 11:03:20 5 18.11 0.0 0.00 7.66 609.1 0.3 0.033 <0.003 Isles 9/9/2015 11:01:58 6 14.84 0.0 0.00 7.41 768.3 0.9 Isles 9/9/2015 11:00:50 7 12.19 0.0 0.00 7.36 779.9 1.7 Isles 9/9/2015 11:00:06 8 10.79 0.0 0.00 7.35 789.8 2.4 0.302 0.283 143 Isles 9/9/2015 10:59:06 9 9.77 0.0 0.00 7.38 823.2 3.6 Loring 9/14/2015 11:24:30 2.80 0 20.63 48.6 4.21 7.47 1545 0 5.89 2.00 9.93 0.124 0.076 0.857 357 Loring 9/14/2015 11:23:49 1 20.26 47.2 4.11 7.46 1545 0 Loring 9/14/2015 11:22:20 2 20.17 42 3.67 7.45 1543 0 Loring 9/14/2015 11:21:26 3 20.08 40 3.5 7.46 1543 0 Loring 9/14/2015 11:20:30 4 19.83 29.7 2.61 7.47 1532 0 0.120 0.076 357 Loring 9/14/2015 11:19:42 4.3 19.5 39.8 3.53 7.53 1510 0 Nokomis 9/15/2015 9:38:15 0.68 0 21.59 88.3 7.56 8.31 472.9 0.0 10.51 7.60 4.158 0.040 <0.003 <0.500 98 Nokomis 9/15/2015 9:37:37 1 21.59 88.2 7.55 8.29 472.4 0.0 Nokomis 9/15/2015 9:36:43 2 21.54 85.3 7.32 8.21 472.6 0.0 Nokomis 9/15/2015 9:35:08 3 21.37 72.6 6.25 8.06 473.5 0.0 Nokomis 9/15/2015 9:34:07 4 21.26 66.9 5.76 8.00 473.7 0.0 0.030 <0.003 Nokomis 9/15/2015 9:32:02 5 21.12 59.0 5.10 7.92 473.8 0.0 Nokomis 9/15/2015 9:31:12 6 21.04 57.1 4.94 7.90 473.7 0.0 Nokomis 9/15/2015 9:29:56 7 21.00 53.4 4.63 7.88 474.2 0.0 0.049 0.003 89 Nokomis 9/15/2015 9:28:27 8 20.93 43.4 3.76 7.83 475.4 0.5 Nokomis 9/15/2015 9:27:45 8.3 20.91 38.5 3.34 7.82 476.6 1.1 Powderhorn 9/14/2015 10:25:44 0.48 0 21.78 109.5 9.31 8.39 339.0 0.0 63.90 11.40 2.550 0.070 <0.003 1.510 76 Powderhorn 9/14/2015 10:25:00 1 21.38 96.7 8.28 8.12 338.3 0.0 Powderhorn 9/14/2015 10:23:31 2 21.35 94.0 8.06 8.01 338.2 0.0 Powderhorn 9/14/2015 10:22:08 3 21.35 94.4 8.10 7.99 338.3 0.0 Powderhorn 9/14/2015 10:19:04 4 21.35 94.4 8.10 7.97 338.1 0.0 0.090 <0.003 Powderhorn 9/14/2015 10:18:19 5 21.32 95.4 8.18 7.97 338.0 0.0 Powderhorn 9/14/2015 10:17:10 6 21.30 95.4 8.18 7.95 338.1 0.0 0.067 <0.003 121 Powderhorn 9/14/2015 10:15:58 7 21.27 92.6 7.95 7.89 338.1 0.0 Powderhorn 9/14/2015 10:15:22 7.2 21.27 92.5 7.94 7.88 338.1 139.1 Spring 9/14/2015 12:18:23 0.80 0 18.15 49 4.45 7.17 2296 2.9 86.1 23.5 16.7 0.224 0.135 1.67 625 Spring 9/14/2015 12:16:39 1 17.04 0.4 0.04 6.91 2524 5.1 Spring 9/14/2015 12:15:34 2 14.72 0.3 0.03 6.7 3737 6.5 Spring 9/14/2015 12:14:50 3 11.11 0 0 6.63 4505 8.1 Spring 9/14/2015 12:13:21 4 8.62 0 0 6.56 4944 12.4 3.570 3.815 Spring 9/14/2015 12:12:04 5 7.49 0 0 6.53 5146 16 Spring 9/14/2015 12:10:25 6 7.14 0 0 6.5 5309 21.4 5.410 5.703 1434 Spring 9/14/2015 12:09:18 6.8 7.11 0 0 6.49 5432 148.6 Wirth 9/11/2015 10:31:28 2.44 0 21.91 91.4 7.86 8.38 766.7 0 4.11 <0.500 5.53 0.022 0.003 0.506 152 Wirth 9/11/2015 10:30:41 1 21.89 91.1 7.83 8.35 766.7 0 Wirth 9/11/2015 10:29:38 2 21.89 88.8 7.64 8.27 767.2 0 Wirth 9/11/2015 10:27:16 3 21.47 24.8 2.15 7.65 794.2 0 Wirth 9/11/2015 10:25:14 4 20.13 0.3 0.03 7.49 816.2 0 0.039 0.003 Wirth 9/11/2015 10:24:02 5 17.83 0 0 7.32 932.4 0 Wirth 9/11/2015 10:21:33 6 14.64 0 0 7.18 1087 0 Wirth 9/11/2015 10:18:53 7 11.7 0 0 7.06 1342 0 1.247 0.685 233 Wirth 9/11/2015 10:17:49 7.5 11 0 0 7.12 1473 0 Calhoun 9/21/2015 10:51:26 3.95 0 19.93 93.1 8.25 8.35 670.9 0.0 1.08 0.70 0.014 0.003 <0.500 149 Calhoun 9/21/2015 10:50:40 1 19.91 93.0 8.23 8.33 670.7 0.0 Calhoun 9/21/2015 10:49:45 2 19.90 92.8 8.22 8.30 670.7 0.0 Calhoun 9/21/2015 10:48:13 3 19.85 91.8 8.14 8.25 670.5 0.0 Calhoun 9/21/2015 10:47:04 4 19.81 91.1 8.08 8.20 670.8 0.0 Calhoun 9/21/2015 10:45:30 5 19.80 88.6 7.86 8.11 671.2 0.0

2015 Water Resources Report - Minneapolis Park Recreation Board Page B23 Date Time Secchi Depth DO pH SpCond TurbSC Chl‐a Pheo‐a Silica TP SRP TKN NO3NO2 Alk Hard SO4 K Ca Mg E. Coli Lake Name MM/DD/YYY HH:MM:SS meters meters Temp °C %DO mg/L units µS/cm NTU mg/M3 mg/M3 mg/L mg/L mg/L mg/L TN mg/L mg/L mg/L mg/L Cl mg/L mg/L mg/L mg/L mg/L mpn/100mL Calhoun 9/21/2015 10:44:34 6 19.73 88.4 7.86 8.02 670.2 0.0 0.015 <0.003 Calhoun 9/21/2015 10:43:41 7 19.45 86.1 7.70 7.90 671.6 0.0 Calhoun 9/21/2015 10:42:26 8 17.69 0.0 0.00 7.40 712.4 0.0 Calhoun 9/21/2015 10:41:32 9 12.43 0.0 0.00 7.33 763.7 0.0 Calhoun 9/21/2015 10:40:22 10 10.99 0.0 0.00 7.31 761.1 0.0 Calhoun 9/21/2015 10:39:21 11 10.19 0.0 0.00 7.30 761.3 0.0 Calhoun 9/21/2015 10:38:09 12 9.16 0.0 0.00 7.29 759.0 0.0 0.048 0.030 Calhoun 9/21/2015 10:36:40 13 8.55 0.0 0.00 7.26 759.7 0.0 Calhoun 9/21/2015 10:34:14 14 8.32 0.0 0.00 7.25 760.6 0.0 Calhoun 9/21/2015 10:32:15 15 8.21 0.0 0.00 7.23 761.0 0.0 Calhoun 9/21/2015 10:31:29 16 8.09 0.0 0.00 7.22 762.6 0.0 Calhoun 9/21/2015 10:30:25 17 8.05 0.0 0.00 7.21 763.0 0.1 Calhoun 9/21/2015 10:29:20 18 8.03 0.0 0.00 7.21 763.2 0.1 0.201 0.182 Calhoun 9/21/2015 10:25:47 19 8.03 0.0 0.00 7.20 763.4 0.2 Calhoun 9/21/2015 10:25:10 20 8.02 0.0 0.00 7.20 763.4 0.2 Calhoun 9/21/2015 10:22:05 21 8.03 0.0 0.00 7.21 763.4 0.5 Calhoun 9/21/2015 10:20:56 22 8.03 0.0 0.00 7.21 763.8 0.2 0.212 0.200 158 Calhoun 9/21/2015 10:19:10 23 8.01 0.0 0.00 7.22 764.9 1.1 Calhoun 9/21/2015 10:17:16 23.3 8.03 0.0 0.00 7.23 765.1 1.7 Cedar 9/21/2015 12:08:40 0.71 0 20.04 85.3 7.54 8.27 681.7 0.0 1.63 0.80 0.027 <0.003 1.030 139 Cedar 9/21/2015 12:07:41 1 20.01 84.7 7.49 8.24 681.6 0.0 Cedar 9/21/2015 12:06:51 2 19.89 83.5 7.39 8.20 682.4 0.0 Cedar 9/21/2015 12:05:25 3 19.82 80.4 7.13 8.11 682.2 0.0 Cedar 9/21/2015 12:04:21 4 19.78 79.3 7.05 8.05 682.7 0.0 Cedar 9/21/2015 12:02:50 5 19.54 66.6 5.94 7.82 686.6 0.0 0.025 <0.003 Cedar 9/21/2015 12:01:27 6 17.11 0.0 0.00 7.40 803.4 0.0 Cedar 9/21/2015 12:00:07 7 12.31 0.0 0.00 7.32 825.9 0.1 Cedar 9/21/2015 11:58:40 8 10.11 0.0 0.00 7.27 831.3 0.3 Cedar 9/21/2015 11:57:23 9 9.14 0.0 0.00 7.24 836.7 0.5 Cedar 9/21/2015 11:56:08 10 8.56 0.0 0.00 7.21 843.1 0.7 0.297 0.257 Cedar 9/21/2015 11:54:59 11 8.18 0.0 0.00 7.20 845.9 1.0 Cedar 9/21/2015 11:53:47 12 7.95 0.0 0.00 7.19 848.8 1.3 Cedar 9/21/2015 11:52:51 13 7.53 0.0 0.00 7.18 858.3 1.6 Cedar 9/21/2015 11:51:52 14 7.37 0.0 0.00 7.17 863.9 2.1 0.486 0.459 163 Cedar 9/21/2015 11:50:51 15 7.24 0.0 0.00 7.19 868.3 2.4 Cedar 9/21/2015 11:49:31 16 7.24 0.0 0.00 7.22 869.6 3.0 Cedar 9/21/2015 11:49:03 16.3 7.23 0.0 0.00 7.25 870.3 22.7 Diamond 9/25/2015 10:11:04 0 19.62 39.6 3.58 7.39 316.5 0.0 26.54 12.00 0.085 0.006 0.820 72 Diamond 9/25/2015 10:09:40 0.6 19.54 24.7 2.24 7.44 316.6 0.0 Harriet 9/22/2015 10:29:19 2.65 0 20.15 97.4 8.63 8.53 609.7 0.0 1.72 0.90 0.019 0.003 0.535 129 Harriet 9/22/2015 10:28:44 1 20.13 97.0 8.60 8.52 609.7 0.0 Harriet 9/22/2015 10:27:53 2 20.07 95.3 8.46 8.46 610.1 0.0 Harriet 9/22/2015 10:27:04 3 20.01 93.6 8.32 8.42 610.8 0.0 Harriet 9/22/2015 10:26:26 4 19.99 93.5 8.31 8.39 609.4 0.0 Harriet 9/22/2015 10:25:36 5 19.91 93.5 8.33 8.35 610.7 0.0 Harriet 9/22/2015 10:23:52 6 19.96 92.5 8.23 8.23 609.2 0.0 0.019 0.004 Harriet 9/22/2015 10:22:39 7 19.64 80.3 7.19 7.97 609.4 0.0 Harriet 9/22/2015 10:21:09 8 15.17 0.0 0.00 7.46 669.9 0.0 Harriet 9/22/2015 10:19:35 9 11.06 0.0 0.00 7.39 670.9 0.0 Harriet 9/22/2015 10:18:22 10 9.55 0.0 0.00 7.34 676.7 0.0 Harriet 9/22/2015 10:17:15 11 8.88 0.0 0.00 7.32 674.7 0.0 Harriet 9/22/2015 10:16:05 12 8.54 0.0 0.00 7.31 674.4 0.0 0.248 0.216 Harriet 9/22/2015 10:15:19 13 8.37 0.0 0.00 7.30 675.4 0.0 Harriet 9/22/2015 10:13:45 14 8.29 0.0 0.00 7.29 676.5 0.0 Harriet 9/22/2015 10:11:19 15 8.21 0.0 0.00 7.29 677.7 0.0 0.352 0.310 Harriet 9/22/2015 10:10:35 16 8.17 0.0 0.00 7.28 678.0 0.0 Harriet 9/22/2015 10:09:39 17 8.16 0.0 0.00 7.27 678.9 0.0 Harriet 9/22/2015 10:08:20 18 8.13 0.0 0.00 7.27 679.9 0.0

2015 Water Resources Report - Minneapolis Park Recreation Board Page B24 Date Time Secchi Depth DO pH SpCond TurbSC Chl‐a Pheo‐a Silica TP SRP TKN NO3NO2 Alk Hard SO4 K Ca Mg E. Coli Lake Name MM/DD/YYY HH:MM:SS meters meters Temp °C %DO mg/L units µS/cm NTU mg/M3 mg/M3 mg/L mg/L mg/L mg/L TN mg/L mg/L mg/L mg/L Cl mg/L mg/L mg/L mg/L mg/L mpn/100mL Harriet 9/22/2015 10:07:12 19 8.10 0.0 0.00 7.27 680.1 0.0 Harriet 9/22/2015 10:03:29 20 8.06 0.0 0.00 7.28 680.9 0.0 0.414 0.376 129 Harriet 9/22/2015 10:02:00 21 8.07 0.0 0.00 7.29 681.1 0.0 Harriet 9/22/2015 10:00:36 22 8.04 0.0 0.00 7.30 681.6 0.0 Harriet 9/22/2015 9:58:50 23 8.07 0.0 0.00 7.32 682.1 0.0 Harriet 9/22/2015 9:57:30 24 8.06 0.0 0.00 7.35 682.4 0.0 Harriet 9/22/2015 9:55:56 24.5 8.03 0.0 0.00 7.41 683.4 0.0 Hiawatha 9/28/2015 11:14:43 0.58 0 20.56 107.7 9.41 8.05 529.6 0.0 17.30 3.00 0.041 0.005 0.886 96 Hiawatha 9/28/2015 11:13:16 1 20.38 100.8 8.84 7.96 531.3 0.0 Hiawatha 9/28/2015 11:12:03 2 20.25 94.6 8.32 7.88 534.4 0.0 Hiawatha 9/28/2015 11:09:36 3 19.72 60.6 5.39 7.66 537.9 0.0 Hiawatha 9/28/2015 11:08:05 4 19.28 28.7 2.57 7.59 537.8 0.0 0.047 0.013 96 Hiawatha 9/28/2015 11:06:34 5 18.66 0.0 0.00 7.57 588.8 0.0 Hiawatha 9/28/2015 11:05:27 6 17.64 0.0 0.00 7.53 734.5 0.1 Hiawatha 9/28/2015 11:04:39 7 17.40 0.3 0.03 7.58 762.8 0.0 Hiawatha 9/28/2015 11:03:25 7.4 17.15 0.0 0.00 7.68 813.2 1.3 Isles 9/21/2015 11:25:45 0.53 0 19.56 81.1 7.23 8.47 570.0 0.0 7.05 4.80 0.047 0.003 1.390 129 Isles 9/21/2015 11:25:04 1 19.47 79.4 7.10 8.43 570.2 0.0 Isles 9/21/2015 11:24:14 2 19.35 76.1 6.82 8.32 571.7 0.0 Isles 9/21/2015 11:23:16 3 19.28 67.2 6.03 8.14 573.1 0.0 Isles 9/21/2015 11:22:40 4 19.06 60.5 5.45 7.99 576.2 0.0 Isles 9/21/2015 11:21:41 5 18.45 0.3 0.03 7.57 615.0 0.0 0.017 <0.003 Isles 9/21/2015 11:20:59 6 15.11 0.0 0.00 7.47 767.3 0.0 Isles 9/21/2015 11:16:43 7 12.40 0.0 0.00 7.19 782.9 1.2 Isles 9/21/2015 11:15:54 8 10.80 0.0 0.00 7.15 798.8 1.8 0.280 0.255 163 Isles 9/21/2015 11:14:44 9 10.03 0.0 0.00 7.13 825.2 3.6 Loring 9/25/2015 11:52:28 2.69 0 20.03 44.2 3.95 7.51 1469 0 3.60 2.90 0.131 0.081 0.879 382 Loring 9/25/2015 11:51:24 1 19.95 41.2 3.69 7.5 1468 0 Loring 9/25/2015 11:50:07 2 19.88 37.9 3.4 7.5 1468 0 Loring 9/25/2015 11:48:56 3 19.87 38.7 3.48 7.51 1468 0 Loring 9/25/2015 11:47:15 4 19.76 28.9 2.6 7.5 1466 0 0.129 0.085 382 Loring 9/25/2015 11:46:11 4.5 19.32 37.8 3.43 7.54 1428 139.7 Nokomis 9/28/2015 10:13:37 0.70 0 20.78 105.3 9.16 8.58 461.3 0.0 15.47 3.50 0.044 0.003 0.995 86 Nokomis 9/28/2015 10:13:04 1 20.81 104.4 9.08 8.55 461.2 0.0 Nokomis 9/28/2015 10:11:31 2 20.70 94.6 8.24 8.40 462.5 0.0 Nokomis 9/28/2015 10:09:56 3 20.59 88.4 7.72 8.27 463.4 0.0 Nokomis 9/28/2015 10:07:46 4 20.54 82.3 7.20 8.12 464.2 0.0 0.046 <0.003 Nokomis 9/28/2015 10:06:10 5 20.45 60.7 5.32 7.91 467.6 0.0 Nokomis 9/28/2015 10:03:55 6 20.35 38.8 3.40 7.80 469.7 0.0 Nokomis 9/28/2015 10:02:39 7 20.32 34.5 3.03 7.80 470.7 0.0 0.049 0.003 86 Nokomis 9/28/2015 10:01:02 8 20.30 28.9 2.54 7.82 472.2 0.0 Nokomis 9/28/2015 9:59:59 8.4 20.26 26.3 2.31 7.88 474.6 0.0 Powderhorn 9/25/2015 10:52:02 0.47 0 20.72 143.0 12.66 9.21 320.3 0.0 69.70 10.60 0.083 <0.003 1.470 76 Powderhorn 9/25/2015 10:51:10 1 20.63 119.1 10.56 8.75 318.0 0.0 Powderhorn 9/25/2015 10:49:44 2 20.37 30.5 2.72 7.20 318.6 0.0 Powderhorn 9/25/2015 10:48:31 3 20.20 9.8 0.88 7.14 321.8 0.0 Powderhorn 9/25/2015 10:46:33 4 20.17 12.1 1.08 7.19 321.4 0.0 0.057 <0.003 Powderhorn 9/25/2015 10:45:14 5 20.16 6.7 0.60 7.21 322.0 0.0 Powderhorn 9/25/2015 10:43:29 6 20.17 1.2 0.11 7.26 323.2 0.0 0.084 0.004 81 Powderhorn 9/25/2015 10:42:02 7 20.17 0.0 0.00 7.32 324.1 5.8 Wirth 9/22/2015 12:18:01 2.95 0 20.4 90.5 7.98 8.18 760.6 0 3.99 <0.500 0.032 0.007 0.520 162 Wirth 9/22/2015 12:17:16 1 20.39 90 7.93 8.14 760.5 0 Wirth 9/22/2015 12:16:15 2 20.3 88.5 7.82 8.07 760.5 0 Wirth 9/22/2015 12:14:07 3 19.96 72.1 6.41 7.87 762.3 0 Wirth 9/22/2015 12:12:15 4 19.36 35.3 3.18 7.64 770.1 0 0.025 0.004 Wirth 9/22/2015 12:10:10 5 18.56 0 0 7.43 850.8 0 Wirth 9/22/2015 12:08:22 6 15.14 0 0 7.24 1063 6.2 Wirth 9/22/2015 12:07:31 7 12.02 0 0 7.11 1333 5.3 1.333 0.708 259

2015 Water Resources Report - Minneapolis Park Recreation Board Page B25 Date Time Secchi Depth DO pH SpCond TurbSC Chl‐a Pheo‐a Silica TP SRP TKN NO3NO2 Alk Hard SO4 K Ca Mg E. Coli Lake Name MM/DD/YYY HH:MM:SS meters meters Temp °C %DO mg/L units µS/cm NTU mg/M3 mg/M3 mg/L mg/L mg/L mg/L TN mg/L mg/L mg/L mg/L Cl mg/L mg/L mg/L mg/L mg/L mpn/100mL Wirth 9/22/2015 12:06:45 7.6 11.16 0 0 7.09 1540 71.5 Calhoun 10/26/2015 10:58:14 3.76 0 12.77 84.7 8.84 8.03 693.9 0.0 0.98 2.00 0.529 0.019 0.003 0.602 0.700 0.104 111 132 137 8.50 3.4 37 13 Calhoun 10/26/2015 10:57:05 1 12.77 84.8 8.85 7.98 694.0 0.0 Calhoun 10/26/2015 10:56:24 2 12.78 83.6 8.73 8.01 693.9 0.0 Calhoun 10/26/2015 10:55:43 3 12.78 84.0 8.77 7.99 693.9 0.0 Calhoun 10/26/2015 10:54:42 4 12.78 83.8 8.75 7.98 694.1 0.0 Calhoun 10/26/2015 10:53:58 5 12.77 83.8 8.75 7.97 693.9 0.0 Calhoun 10/26/2015 10:53:12 6 12.77 82.3 8.59 7.94 694.3 0.0 0.019 0.003 Calhoun 10/26/2015 10:52:02 7 12.77 83.0 8.66 7.92 694.2 0.0 Calhoun 10/26/2015 10:51:12 8 12.77 81.3 8.49 7.90 694.0 0.0 Calhoun 10/26/2015 10:49:25 9 12.75 80.5 8.40 7.84 694.5 0.0 Calhoun 10/26/2015 10:47:41 10 12.71 78.6 8.21 7.78 693.3 0.0 Calhoun 10/26/2015 10:46:03 11 12.60 70.8 7.42 7.64 692.1 0.0 Calhoun 10/26/2015 10:44:37 12 11.10 0.0 0.00 7.44 741.4 0.0 0.021 0.003 Calhoun 10/26/2015 10:43:36 13 8.73 0.0 0.00 7.39 767.6 0.0 Calhoun 10/26/2015 10:42:42 14 8.36 0.0 0.00 7.37 769.6 0.0 Calhoun 10/26/2015 10:41:39 15 8.20 0.0 0.00 7.37 771.3 0.0 Calhoun 10/26/2015 10:41:04 16 8.10 0.0 0.00 7.36 773.0 0.0 Calhoun 10/26/2015 10:40:03 17 8.06 0.0 0.00 7.36 772.9 0.0 Calhoun 10/26/2015 10:39:20 18 8.04 0.0 0.00 7.36 772.1 0.0 0.239 0.224 Calhoun 10/26/2015 10:38:35 19 8.03 0.0 0.00 7.36 773.8 0.0 Calhoun 10/26/2015 10:36:51 20 7.99 0.0 0.00 7.37 774.1 0.0 Calhoun 10/26/2015 10:34:45 21 7.98 0.0 0.00 7.39 775.0 0.0 Calhoun 10/26/2015 10:33:50 22 7.98 0.0 0.00 7.41 775.3 0.0 0.277 0.249 142 6.90 Calhoun 10/26/2015 10:33:07 23 7.97 0.0 0.00 7.42 775.9 0.0 Calhoun 10/26/2015 10:32:16 24 7.95 0.0 0.00 7.43 781.4 8.4 Cedar 10/26/2015 12:26:08 1.42 0 12.61 81.8 8.57 7.98 729.7 0.0 2.24 5.20 2.883 0.047 0.003 1.275 1.479 0.131 125 164 142 11.55 3.6 44 16 Cedar 10/26/2015 12:25:27 1 12.59 81.5 8.54 7.97 729.8 0.0 Cedar 10/26/2015 12:24:24 2 12.57 80.9 8.48 7.94 729.8 0.0 Cedar 10/26/2015 12:23:13 3 12.54 79.5 8.34 7.88 729.5 0.0 Cedar 10/26/2015 12:22:23 4 12.52 79.3 8.32 7.88 729.6 0.0 Cedar 10/26/2015 12:21:27 5 12.53 79.3 8.32 7.85 729.7 0.0 0.052 0.004 Cedar 10/26/2015 12:20:30 6 12.51 79.6 8.35 7.80 729.8 0.0 Cedar 10/26/2015 12:19:23 7 12.50 73.7 7.74 7.73 730.5 0.0 Cedar 10/26/2015 12:17:45 8 12.41 52.4 5.51 7.56 740.3 0.0 Cedar 10/26/2015 12:16:13 9 11.13 0.0 0.00 7.34 821.5 0.0 Cedar 10/26/2015 12:14:41 10 8.86 0.0 0.00 7.29 854.5 0.0 0.344 0.281 Cedar 10/26/2015 12:13:42 11 8.30 0.0 0.00 7.28 856.5 0.0 Cedar 10/26/2015 12:11:31 12 7.97 0.0 0.00 7.27 862.4 0.1 Cedar 10/26/2015 12:08:48 13 7.56 0.0 0.00 7.25 872.1 0.3 Cedar 10/26/2015 12:07:44 14 7.34 0.0 0.00 7.24 880.8 0.4 0.513 0.483 146 11.20 Cedar 10/26/2015 12:07:00 15 7.29 0.0 0.00 7.25 884.2 0.6 Cedar 10/26/2015 12:06:14 16 7.26 0.0 0.00 7.27 887.4 0.9 Cedar 10/26/2015 12:04:39 16.4 7.22 0.0 0.00 7.31 891.7 0.7 Diamond 10/29/2015 9:48:34 0 7.89 60.1 6.87 8.06 379.1 0.3 2.47 2.90 1.263 0.072 0.015 1.460 1.593 0.080 56 56 77 5.80 Diamond 10/29/2015 9:49:18 0.6 7.94 59.6 6.81 8.02 378.4 14.0 Harriet 10/27/2015 9:56:21 2.99 0 12.65 80.6 8.39 7.99 623.5 0.0 1.09 0.90 <0.500 0.030 0.005 0.726 0.839 0.103 104 132 119 7.70 3.4 34 13 Harriet 10/27/2015 9:55:05 1 12.66 80.7 8.40 7.98 623.5 0.0 Harriet 10/27/2015 9:54:23 2 12.67 80.1 8.34 7.98 623.4 0.0 Harriet 10/27/2015 9:53:36 3 12.66 79.9 8.32 7.95 623.9 0.0 Harriet 10/27/2015 9:52:16 4 12.66 79.7 8.29 7.93 623.4 0.0 Harriet 10/27/2015 9:51:21 5 12.66 79.7 8.30 7.92 623.4 0.0 Harriet 10/27/2015 9:49:59 6 12.66 79.6 8.29 7.89 623.4 0.0 0.030 0.005 Harriet 10/27/2015 9:47:36 7 12.66 79.9 8.32 7.83 623.4 0.0 Harriet 10/27/2015 9:46:53 8 12.66 79.6 8.29 7.80 623.6 0.0 Harriet 10/27/2015 9:46:03 9 12.65 78.5 8.17 7.76 623.3 0.0 Harriet 10/27/2015 9:44:34 10 12.64 74.6 7.77 7.69 624.1 0.0 Harriet 10/27/2015 9:42:16 11 10.65 0.0 0.00 7.35 669.9 0.0

2015 Water Resources Report - Minneapolis Park Recreation Board Page B26 Date Time Secchi Depth DO pH SpCond TurbSC Chl‐a Pheo‐a Silica TP SRP TKN NO3NO2 Alk Hard SO4 K Ca Mg E. Coli Lake Name MM/DD/YYY HH:MM:SS meters meters Temp °C %DO mg/L units µS/cm NTU mg/M3 mg/M3 mg/L mg/L mg/L mg/L TN mg/L mg/L mg/L mg/L Cl mg/L mg/L mg/L mg/L mg/L mpn/100mL Harriet 10/27/2015 9:40:57 12 8.79 0.0 0.00 7.31 679.0 0.0 0.169 0.149 Harriet 10/27/2015 9:39:50 13 8.43 0.0 0.00 7.29 680.0 0.0 Harriet 10/27/2015 9:37:42 14 8.26 0.0 0.00 7.28 682.4 0.0 Harriet 10/27/2015 9:35:55 15 8.20 0.0 0.00 7.27 683.4 0.0 0.418 0.391 Harriet 10/27/2015 9:34:51 16 8.11 0.0 0.00 7.26 684.2 0.0 Harriet 10/27/2015 9:33:39 17 8.07 0.0 0.00 7.26 685.4 0.0 Harriet 10/27/2015 9:32:33 18 8.04 0.0 0.00 7.25 686.7 0.0 Harriet 10/27/2015 9:30:52 19 8.01 0.0 0.00 7.27 688.2 0.0 Harriet 10/27/2015 9:30:08 20 8.00 0.0 0.00 7.27 688.4 0.0 0.509 0.489 128 6.10 Harriet 10/27/2015 9:29:08 21 7.99 0.0 0.00 7.27 690.4 0.0 Harriet 10/27/2015 9:27:13 22 7.98 0.0 0.00 7.29 691.0 0.0 Harriet 10/27/2015 9:25:43 23 7.96 0.0 0.00 7.32 692.3 0.0 Harriet 10/27/2015 9:23:31 24 8.04 0.0 0.00 7.39 694.1 1.4 Hiawatha 10/30/2015 11:06:09 0.88 0 9.98 57.8 6.37 7.82 511.9 0.0 7.00 1.90 1.565 0.066 0.020 0.864 1.070 0.097 133 160 82 8.70 Hiawatha 10/30/2015 11:05:29 1 9.96 57.7 6.37 7.83 512.3 0.0 Hiawatha 10/30/2015 11:04:27 2 9.96 57.3 6.33 7.83 512.3 0.0 Hiawatha 10/30/2015 11:03:37 3 9.95 57.4 6.33 7.84 512.5 0.0 Hiawatha 10/30/2015 11:01:59 4 9.95 57.4 6.33 7.87 512.8 0.0 0.084 0.020 82 8.30 Hiawatha 10/30/2015 11:00:55 5 9.95 57.3 6.32 7.88 511.8 0.0 Hiawatha 10/30/2015 10:58:46 6 9.95 57.3 6.32 7.95 512.6 0.0 Hiawatha 10/30/2015 10:57:47 6.4 9.93 57.5 6.34 7.99 512.4 0.0 Isles 10/26/2015 11:29:25 1.62 0 11.93 65.1 6.93 7.88 622.4 0.0 3.64 3.50 0.788 0.055 0.004 1.590 1.710 0.098 100 120 146 6.50 Isles 10/26/2015 11:28:26 1 11.92 65.1 6.93 7.88 622.3 0.0 Isles 10/26/2015 11:27:38 2 11.91 64.6 6.87 7.88 622.2 0.0 Isles 10/26/2015 11:26:41 3 11.90 63.9 6.80 7.88 622.3 0.0 Isles 10/26/2015 11:25:31 4 11.90 64.0 6.81 7.89 622.2 0.0 Isles 10/26/2015 11:24:48 5 11.90 63.7 6.79 7.88 622.6 0.0 0.058 0.004 Isles 10/26/2015 11:23:52 6 11.87 63.1 6.73 7.89 622.3 0.0 Isles 10/26/2015 11:21:56 7 11.83 59.8 6.38 7.90 622.9 0.0 Isles 10/26/2015 11:20:40 8 11.81 58.9 6.28 7.92 622.7 0.0 0.051 0.004 123 6.30 Isles 10/26/2015 11:19:47 9 11.78 55.1 5.88 7.93 624.3 8.2 Loring 10/29/2015 11:37:59 2.15 0 10.27 73.5 7.92 7.74 1383 0 1.7 6.40 8.65 0.144 0.072 1.350 1.786 0.438 201 280 315 19.6 Loring 10/29/2015 11:37:16 1 10.27 73.5 7.9 7.73 1383 0 Loring 10/29/2015 11:35:53 2 10.27 72.8 7.83 7.72 1383 0 Loring 10/29/2015 11:34:45 3 10.26 73.1 7.86 7.72 1383 0 Loring 10/29/2015 11:33:05 4 10.26 73.2 7.87 7.71 1382 0 0.147 0.072 338 21.1 Loring 10/29/2015 11:31:44 4.4 10.26 73 7.86 7.72 1382 0 Nokomis 10/30/2015 10:01:26 1.22 0 10.96 83.0 8.95 8.13 476.5 0.0 12.07 3.40 4.847 0.058 <0.003 1.620 1.910 0.190 99 112 91 5.90 3.6 36 6 Nokomis 10/30/2015 10:00:39 1 10.97 83.6 9.00 8.13 476.8 0.0 Nokomis 10/30/2015 9:59:50 2 10.97 83.2 8.96 8.12 477.3 0.1 Nokomis 10/30/2015 9:59:03 3 10.97 83.3 8.97 8.12 476.9 0.2 Nokomis 10/30/2015 9:58:09 4 10.97 83.1 8.95 8.12 477.2 0.4 0.061 0.003 Nokomis 10/30/2015 9:57:25 5 10.96 83.2 8.96 8.13 476.1 0.8 Nokomis 10/30/2015 9:56:19 6 10.94 83.5 9.00 8.14 475.8 1.2 Nokomis 10/30/2015 9:55:17 7 10.94 83.5 9.00 8.14 476.6 3.1 0.064 0.003 82 6.20 Nokomis 10/30/2015 9:54:01 8 10.92 82.7 8.92 8.17 477.2 9.6 Nokomis 10/30/2015 9:53:00 8.2 10.93 73.2 7.89 8.20 476.8 38.5 Powderhorn 10/29/2015 10:27:27 0.48 0 10.51 78.2 8.40 8.00 295.9 0.0 11.67 1.90 3.551 0.154 0.003 1.350 1.380 0.031 37 36 68 6.10 Powderhorn 10/29/2015 10:26:18 1 10.51 78.1 8.39 8.02 295.6 0.0 Powderhorn 10/29/2015 10:25:18 2 10.51 78.4 8.42 8.04 295.0 0.0 Powderhorn 10/29/2015 10:24:09 3 10.52 78.0 8.38 8.08 295.7 0.0 Powderhorn 10/29/2015 10:23:23 4 10.51 77.9 8.37 8.10 295.5 0.0 0.155 0.003 Powderhorn 10/29/2015 10:22:34 5 10.51 78.0 8.38 8.13 295.6 0.0 Powderhorn 10/29/2015 10:21:51 6 10.51 78.0 8.37 8.16 295.5 0.0 0.146 0.003 68 6.00 Powderhorn 10/29/2015 10:21:06 6.7 10.51 77.7 8.34 8.20 295.6 0.0 Spring 10/29/2015 12:19:55 0.42 0 10.05 2.7 0.29 7.15 2674 0 114 311 18.8 0.639 0.264 3.44 3.53 0.045 324 530 816 65.3 Spring 10/29/2015 12:18:10 1 9.98 0 0 7.09 2677 0 Spring 10/29/2015 12:17:27 2 10.06 0 0 7.02 2675 0.1

2015 Water Resources Report - Minneapolis Park Recreation Board Page B27 Date Time Secchi Depth DO pH SpCond TurbSC Chl‐a Pheo‐a Silica TP SRP TKN NO3NO2 Alk Hard SO4 K Ca Mg E. Coli Lake Name MM/DD/YYY HH:MM:SS meters meters Temp °C %DO mg/L units µS/cm NTU mg/M3 mg/M3 mg/L mg/L mg/L mg/L TN mg/L mg/L mg/L mg/L Cl mg/L mg/L mg/L mg/L mg/L mpn/100mL Spring 10/29/2015 12:16:48 3 11.38 0.2 0.02 6.72 4335 0.3 Spring 10/29/2015 12:16:14 4 9.77 0 0 6.66 4863 0.4 3.649 3.602 Spring 10/29/2015 12:14:49 5 8.23 0 0 6.63 5131 0.4 Spring 10/29/2015 12:13:36 6 7.55 0 0 6.62 5300 0.3 6.343 6.018 1881 92.9 Spring 10/29/2015 12:12:21 7 7.25 0 0 6.63 5484 0.3 Spring 10/29/2015 12:10:49 7.3 7.23 0 0 6.71 5618 2.1 Wirth 10/27/2015 11:11:49 2.95 0 12.11 72.9 7.68 7.87 818.3 0 <0.500 3.70 8.7 0.038 0.006 0.747 0.828 0.081 156 240 160 9.8 3.10 50.0 30.0 Wirth 10/27/2015 11:10:50 1 12.13 72.7 7.66 7.86 818.1 0 Wirth 10/27/2015 11:09:09 2 12.12 72.6 7.65 7.86 818.5 0 Wirth 10/27/2015 11:08:04 3 12.11 72.9 7.68 7.84 818.5 0 Wirth 10/27/2015 11:06:57 4 12.11 76.2 8.03 7.84 819 0 0.045 0.004 Wirth 10/27/2015 11:05:39 5 12.09 77.4 8.16 7.81 819.6 0 Wirth 10/27/2015 11:04:25 6 12.02 75.8 8 7.77 822.2 0 Wirth 10/27/2015 11:02:50 7 11.9 17.8 1.88 7.47 967.4 0 0.460 0.053 172 7.9 Wirth 10/27/2015 10:59:16 7.6 11.57 0 0 7.44 1326 0.1

2015 Water Resources Report - Minneapolis Park Recreation Board Page B28