Vermillion River Section

Compreh ensive Water Quality Assessment of Select Metropolitan Area Streams

VERMILLION RIVER

December 2014 The Council’s mission is to foster efficient and economic growth for a prosperous metropolitan region.

Metropolitan Council Members

Susan Haigh Chair Edward Reynoso District 9 Katie Rodriguez District 1 Marie McCarthy District 10 Lona Schreiber District 2 Sandy Rummel District 11 Jennifer Munt District 3 Harry Melander District 12 Gary Van Eyll District 4 Richard Kramer District 13 Steve Elkins District 5 Jon Commers District 14 James Brimeyer District 6 Steven T. Chávez District 15 Gary L. Cunningham District 7 Wendy Wulff District 16 Adam Duininck District 8

The Metropolitan Council is the regional planning organization for the seven-county Twin Cities area. The Council operates the regional bus and rail system, collects and treats wastewater, coordinates regional water resources, plans and helps fund regional parks, and administers federal funds that provide housing opportunities for low- and moderate-income individuals and families. The 17-member Council board is appointed by and serves at the pleasure of the governor.

This publication printed on recycled paper.

On request, this publication will be made available in alternative formats to people with disabilities. Call Metropolitan Council information at 651-602-1140 or TTY 651-291-0904. About the Study The Twin Cities metropolitan area has a wealth of streams that traverse its landscape and ultimately flow into one of its three major rivers – the Mississippi, the Minnesota, and the St. Croix. These streams provide rich habitat for aquatic life and wildlife and enhance the recreational and aesthetic value of the metro area. The Metropolitan Council is committed to the conscientious stewardship of the region’s streams and works with its partners to maintain and improve their health and function. The foundation for these efforts is the collection and analysis of high-quality data about their condition over time. The Comprehensive Water Quality Assessment of Select Metropolitan Area Streams is a major study conducted by the Metropolitan Council that examines the water quality of 21 streams or stream segments that discharge into the metropolitan area’s major rivers. The study provides a base of technical information that can support sound decisions about water resources in the metro area − decisions by the Council, state agencies, watershed districts, conservation districts, and county and city governments. All background information, methodologies, and data sources are summarized in Introduction and Methodologies, and a glossary and a list of acronyms are included in Glossary and Acronyms. Both of these, as well as individual sections for each of the 21 streams, are available for separate download from the report website. The staff of Metropolitan Council Environmental Services (MCES) and local partners conducted the stream monitoring work, while MCES staff performed the data analyses, compiled the results and prepared the report. About This Section This section of the report, Vermillion River, is one in a series produced as part of the Comprehensive Water Quality Assessment of Select Metropolitan Area Streams. Located in Dakota, Scott, and Goodhue counties, the Vermillion River is one of the eight Mississippi River tributaries examined. This section discusses a wide range of factors that have affected the condition and water quality of the Vermillion River. Cover Photo The photo on the cover of this section depicts the Vermillion River near mile 15.6. It was taken by Metropolitan Council staff. Recommended Citations Please use the following to cite this section of the report:

Metropolitan Council. 2014. Vermillion River. In Comprehensive water quality assessment of select metropolitan area streams. St. Paul: Metropolitan Council.

Please use the following to cite the entire report:

Metropolitan Council. 2014. Comprehensive water quality assessment of select metropolitan area streams. St. Paul: Metropolitan Council.

Comprehensive Water Quality Assessment of Select Metropolitan Area Streams | Metropolitan Council Vermillion River i Content Introduction ...... 1 Partnerships and Funding ...... 2 Monitoring Station Descriptions ...... 2 Stream and Watershed Description ...... 3 Water Quality Impairments ...... 10 Hydrology ...... 12 Vulnerability of Stream to Groundwater Withdrawals ...... 16 Pollutant Loads ...... 17 Dissolved Oxygen Assessment ...... 25 Flow and Load Duration Curves ...... 27 Aquatic Life Assessment Based on Macroinvertebrates ...... 31 Trend Analysis ...... 35 Comparison with Other Metro Area streams ...... 49 Conclusions ...... 60 Recommendations ...... 61 Citations ...... 63

Figures Figure VR-1: Vermillion River near the Empire Wastewater Treatment Plant, approximately 15 miles upstream of Hastings, Minnesota ...... 1 Figure VR-2: Vermillion River Hybrid Land Cover ...... 6 Figure VR-3: Vermillion River Watershed Topography ...... 8 Figure VR-4: Vermillion River Public and Impaired Waters and Potential Pollution Sources ... 9 Figure VR-5: Vermillion River Daily Average Flow, Sample Flow, and Precipitation, 1995-2012 ...... 14 Figure VR-6: Vermillion River at Empire Daily Flow, Empire WWTP Effluent Flow, and WWTP Percent of Flow, 2000-2012 ...... 15 Figure VR-7: Groundwater and surface water elevations between the cities of Vermillion and Hastings (courtesy of Dakota County) ...... 16 Figure VR-8: Vermillion River Annual Mass Load, 1995-2012 ...... 19 Figure VR-9: Vermillion River Annual Flow-Weighted Mean Concentrations, 1995-2012 ...... 20 Figure VR-10: Vermillion River Annual Areal-Weighted Load, 1995-2012 ...... 21 Figure VR-11: Vermillion River Annual Precipitation-Weighted Areal Load, 1995-2012 ...... 22 Figure VR-12: Vermillion River Mass Load by Month ...... 23

Comprehensive Water Quality Assessment of Select Metropolitan Area Streams | Metropolitan Council Vermillion River ii Figure VR-13: Vermillion River Flow-Weighted Mean Concentration by Month ...... 24 Figure VR-14: Vermillion River at Empire (VR15.6) Daily Dissolved Oxygen Flux ...... 27 Figure VR-15 Flow and Duration Curves, 1995-2012 ...... 30 Figure VR-16: Vermillion River Annual Family Biotic Index (FBI) Scores, 2001-2011 ...... 32 Figure VR-17: Vermillion River Percent Abundance of Pollution Intolerant Taxa, 2001-2011 .33 Figure VR-18: Vermillion River Percent Abundance of POET Taxa, 2001-2011 ...... 34 Figure VR-19: Vermillion River Annual Macroinvertebrate Index of Biological Integrity (M-IBI) Scores, 2004-2011 ...... 35

Figure VR-20: Vermillion River 20.6 Trends for TSS, TP, Chl-a and NO3 ...... 41

Figure VR-21: Vermillion River 15.6 Trends for TSS, TP, Chl-a and NO3 ...... 42

Figure VR-22: Vermillion River 2.0 Trends for TSS, TP and NO3 ...... 43 Figure VR-23: Populations in Cities of Farmington, Apple Valley, and Lakeville, 1970-2012 .44 Figure VR-24: Annual Mass of TP in WWTP Effluent Discharged to Vermillion River: 1970- 2012 ...... 44 Figure VR-25: Vermillion River TP Concentrations at Farmington, Empire, and Hastings, 1970-2012 ...... 45 Figure VR-26: Nitrate Concentrations in Empire WWTP Effluent and the Vermillion River at Hastings (VR2.0), Empire (VR15.6), and Farmington (VR20.6) and Flow in the Vermillion River at Hastings: 2006-2012 ...... 48 Figure VR-27: General Schematic of a Box-and-Whisker Plot ...... 49 Figure VR-28: Total Suspended Solids for MCES-Monitored Streams, 2003-2012 ...... 51 Figure VR-29: Total Phosphorus for MCES-Monitored Streams, 2003-2012 ...... 52 Figure VR-30: Nitrate for MCES-Monitored Streams, 2003-2012 ...... 53 Figure VR-31: Chloride for MCES-Monitored Streams, 2003-2012 ...... 54 Figure VR-32: M-IBI Results for MCES-Monitored Streams, 2004-2011 ...... 56 Figure VR-33: Estimated Trends in Flow-Adjusted Stream Concentrations of TSS, TP, and NO3 in the Seven-County Metropolitan Area, 2008-2012 ...... 58 Figure VR-34: Regional Maps of Estimated Trends in Flow-Adjusted Stream Concentrations of TSS, TP, and NO3 in the Seven-County Metropolitan Area, 2008-2012 ...... 59

Tables Table VR-1: Vermillion River Land Cover Classes1...... 5 Table VR-2: Permitted Domestic Wastewater Treatment Facilities Discharging to the Vermillion River ...... 7 Table VR-3: Impaired Reaches in the Vermillion River Watershed as Identified on the MPCA 2014 Impaired Waters List ...... 11 Table VR-4: Impaired Lakes in the Vermillion River Watershed as Identified on the MPCA 2014 Impaired Waters List ...... 12

Comprehensive Water Quality Assessment of Select Metropolitan Area Streams | Metropolitan Council Vermillion River iii Table VR-5: Vermillion River Summer Daily Minimum Dissolved Oxygen, 2006-2012 ...... 26 Table VR-6: Vermillion River Winter Minimum Dissolved Oxygen, 2006-2012 ...... 26 Table VR-7: Vermillion River Beneficial Use and River Nutrient Region (RNR) Classifications and Pollutant Draft Standards ...... 29 Table VR-8: Annual Median Concentrations, Loads, and Yields for MCES-Monitored Streams, 2003-2012 ...... 55

Comprehensive Water Quality Assessment of Select Metropolitan Area Streams | Metropolitan Council Vermillion River iv Introduction The Vermillion River is located in the southeast metropolitan area and is a tributary to the Mississippi River (Figure VR-1). It drains approximately 312 square miles of agricultural areas, forest, wetlands, grasses, and urban areas (cities of Elko New Market, Apple Valley, Lakeville, Farmington, and Hastings) through portions of Scott, Dakota, and Goodhue counties.

Figure VR-1: Vermillion River near the Empire Wastewater Treatment Plant, approximately 15 miles upstream of Hastings, Minnesota

This report:

• documents those characteristics of the Vermillion River and its watershed most likely to influence stream flow and water quality.

• presents the results from assessments of flow, water quality, and biological data.

• presents statistical assessments of trends in stream chemistry concentrations.

• draws conclusions about possible effects of landscape features, climatological changes, and human activities on flow and water quality.

• compares the Vermillion River flow and water quality with other streams within the metropolitan area monitored by Metropolitan Council Environmental Services (MCES).

• makes general recommendations for future monitoring and assessment activities, for potential MCES collaborations with local watershed management organizations, and other potential actions to remediate any water quality or flow concerns.

Comprehensive Water Quality Assessment of Select Metropolitan Area Streams | Metropolitan Council Vermillion River 1 MCES plans to update this report approximately every five to 10 years, in addition to issuing annual data summary reports. Partnerships and Funding MCES has supported water quality monitoring of the Vermillion River immediately downstream of Highway 61 in the city of Hastings since 1995. MCES partners with the Dakota County Soil and Water Conservation District (SWCD) to operate the monitoring station as part of MCES’s WOMP (Watershed Outlet Monitoring Program) program, which is funded solely by MCES.

The Vermillion River Watershed Joint Powers Organization (VRWJPO; formed 2002) is the local water management organization charged with development and implementation of policies, programs, and projects that protect and preserve water resources within the watershed. MCES staff serve on the Technical Advisory Group (TAG) for the VRWJPO. The VRWJPO works closely with other organizations, like MnDNR, the University of Minnesota, the Minnesota Outdoor Heritage Fund, and Trout Unlimited to perform projects that protect both the trout habitat in the river and the watershed’s water resources (VRWJPO, 2011).

In addition to the work the VRWJPO accomplishes in the watershed, Friends of the Mississippi River (FMR), MnDNR, Dakota County SWCD, and MCES have worked collaboratively to improve the 400-acre MCES property at the Empire Wastewater Treatment Plant (WWTP) in Empire Township. Collaborative projects have included a natural resources management plan (FMR, et al., 2002), streambank stabilization and trout habitat restoration, restoration of a 50- acre wet meadow wetland, and removal of invasive species including buckthorn and purple loosestrife. During the WWTP expansion of 2004-2007, MCES used the natural resources plan to site a number of innovative stormwater practices within the plant process area, including three bioinfiltration basins, five pervious paver parking areas, vegetated swales to transport runoff, a green (vegetated) roof, and a prairie plant garden.

In 2002 MCES funded the SWCD to prepare a Vermillion River headwaters groundwater recharge area inventory and protection plan (Emmons and Olivier Resources, Inc., 2007). Goals of the plan included identification of groundwater recharge areas; identification of the relationship between recharge, river flow, and potential development impacts; prioritization of stormwater infiltration areas; and guidance for incorporation protection of groundwater recharge areas into community plans. Monitoring Station Descriptions The WOMP monitoring station was originally located on the north bank of the Vermillion River inside the ConAgra Mill near Highway 61 in Hastings, Minnesota, about two miles upstream from the Mississippi River floodplain, and is referred to as VR 2.0. In 2010 the station was moved to the south side of the river, almost directly across from the original location.

The flow monitoring station includes continuous stage monitoring (OTT PLS Pressure Transducer) and an automatic water sampler (Hach Sigma Sampler) which was used when composite samples were collected. The rating curve at this location is based on a relationship between a staff gauge and water level. An in-situ turbidity probe, previously deployed just upstream of the WOMP station during 2009-2011 by the VRWJPO, was installed at the station in 2012. During 2007-2012 only grab samples were collected from the station; no event composite samples have been collected since 2006 due to infrastructural and technical difficulties.

Comprehensive Water Quality Assessment of Select Metropolitan Area Streams | Metropolitan Council Vermillion River 2 There is no rain gauge at this station; however, precipitation data are obtained from the Minnesota Climatology Working Group, Hastings Dam Station Number 213567. Daily precipitation totals from this station were used to create the hydrograph in the Hydrology section of this report. For the analysis of precipitation-weighted loads, MCES used the Minnesota Climatological Working Group's monthly 10-kilometer gridded precipitation data to represent the variability of rainfall within the watersheds (Minnesota Climatology Working Group, 2013). These data are generated from Minnesota's HIDEN (High Spatial Density Precipitation Network) dataset. The gridded data was aerially weighted based on the watershed boundaries.

MCES also conducts grab sample monitoring at three locations in the upper watershed as part of its river monitoring program. Three sampling locations - VR20.6 (Vermillion River near Farmington), VR15.6 (Vermillion River near Empire), and VR 2.7 (Vermillion River near Hastings) – were established in the late 1970’s to assess water quality effects of effluent discharge from the Empire WWTP. The Farmington and Empire stations are located upstream and downstream, respectively, of the original Empire WWTP effluent discharge pipe. These stations include auto-monitoring equipment (dissolved oxygen, specific conductance, and temperature) and manual collection of weekly or biweekly grab samples, which are analyzed for bacteria, nutrients chloride, oxygen demand, and suspended solids. The third river monitoring station (VR 2.7) is located 0.7 miles upstream of the WOMP station. Monitoring at this station is limited to auto-monitoring (dissolved oxygen, conductance, and temperature) and grab sampling for bacteria and ammonia. This report focuses on the data collected at the WOMP station (VR 2.0) and will include limited discussion of the upstream river monitoring sites. Stream and Watershed Description The Vermillion River flows through Scott, Dakota, and Goodhue counties and has a drainage area of approximately 312 square miles. The Vermillion River has several headwaters, for example the outlet of Lake Marion in the city of Lakeville and wetlands in New Market and Castle Rock townships. The river generally flows to the east for 43 miles until it flows over the Vermillion Falls (also known as the Hastings Dam) south of Highway 61, through the Vermillion River gorge, and under a railroad bridge, which MCES uses as the Mile 0.0 designation for the river. Downstream of the railroad bridge, the river splits, with one branch flowing north to the Mississippi River and the second branch flowing south, paralleling the Mississippi River within its floodplain for approximately 20 miles before joining the river near the city of Red Wing (VRWJPO, 2005).

The portion of the Vermillion River in Scott and Dakota counties lies within the seven-county metropolitan area and the Metropolitan Council’s jurisdiction (Council Districts 4, 15, and 16). In 1988 and 2003 portions of the Vermillion River and its tributaries were designated as trout stream by the MnDNR [M.S. § 97C.005, Special Management Waters; (VRWJPO, 2005)].

In addition to the Vermillion River, there are many other open water bodies within the watershed. For example, Lake Alimagnet (104 acres), Long Lake (36 acres), Farquar Lake (64 acres), Lake Marion (530 acres), Potters Lake (8 acres), and Rice Lake (55 acres) are lakes in the Vermillion River watershed. For more information about lakes in the watershed, please see the Lake Finder website from the MnDNR (MnDNR, 2014).

Additionally, there are a number of tributaries that feed into the Vermillion River, including South, Middle, and North Creeks and the North and South Branches. The largest tributary, the

Comprehensive Water Quality Assessment of Select Metropolitan Area Streams | Metropolitan Council Vermillion River 3 South Branch, enters the main stem of the Vermillion River near river mile 12, downstream of the former location of the Empire WWTP effluent outfall.

The Vermillion River watershed is a total of 199,474 acres, with 149,436 acres (74.9%) of the watershed upstream of the monitoring station. The entire watershed has 98,271 acres/49.3% (75,416 acres/50.5% monitored) agricultural land and 47,070 acres/23.6% (39,867 acres/26.7% monitored) developed urban land (Table VR-1; Figure VR-2). The urban area includes the cities of Farmington, Hampton, Coates, and Vermillion, the majority of Elko New Market and Hastings, and portions of Burnsville, Apple Valley, Lakeville, Rosemount and Red Wing.

Along with the 50,038 unmonitored acres in the Vermillion River watershed downstream of the monitoring station, a 23,427 acre section of land topographically drains to the Vermillion River, but is excluded from the watershed discussion for this study. This area is north of the mapped watershed, encompassing portions of Apple Valley, Eagan, Inver Grove Heights, Sunfish Lake, and Rosemount. It has been determined that the majority of surface water in this area is either infiltrated to groundwater, landlocked, or drains by overland flow directly to the Mississippi River (M. Zabel, VRWJPO, personal communication, 2015).

Based on the United States Department of Agriculture (USDA) National Agricultural Statistics Service (NASS) 2009 Cropland Data Layer of agricultural land in the watershed, 43% (42% within the monitored area) is planted in corn and 23% (23% within the monitored area) in soybeans. According to a statewide estimate of potentially draintiled fields by University of Minnesota researchers (D. Mulla, University of Minnesota, personal communication, 2012), 4% of the agricultural land in the monitored and total watershed is potentially draintiled.

The geologic history of a watershed dictates many soil and hydrologic properties and surface topography. The Vermillion River watershed was last glaciated during the Wisconsin Glaciation, which began approximately 75,000 years ago (Lusardi, 1997). Two separate lobes of the glacier advanced and retreated over the watershed. The Superior Lobe was first, and it formed the St. Croix moraine till and outwash plain in the northeast part of the watershed. The second lobe was the Des Moines Lobe which formed the Bemis moraine present in the western part of the watershed (Balaban and Hobbs, 1990). As the glaciers retreated they exposed the limestone, dolomite, sandstone, and shale bedrock. Additionally, sandy outwash was deposited, which is the present-day target of many quarries in the Vermillion River watershed.

Past studies (Almendinger and Mitton, 1995; Dakota County, 2003) indicate that the complicated geology of the watershed drives both shallow groundwater discharge to the river, as well as flow from the river to surficial groundwater. A buried valley of an ancient precursor to the Mississippi River cuts across the Vermillion River from northeast to southwest upstream of the city of Hastings, near the city of Vermillion. The depth-to-bedrock in the buried valley (which is filled with later glacial outwash) is greater than 500 feet, in contrast to a depth of less than 50 feet outside of the buried valley. The buried valley provides a conduit for river water to flow downward to surficial aquifers. See the Hydrology section for more information.

Comprehensive Water Quality Assessment of Select Metropolitan Area Streams | Metropolitan Council Vermillion River 4 Table VR-1: Vermillion River Land Cover Classes1 Monitored Unmonitored Total Land Cover Class Acres Percent Acres Percent Acres Percent 5-10% Impervious 7,076 4.7% 1,856 3.7% 8,932 4.5% 11-25% Impervious 5,726 3.8% 2,837 5.7% 8,562 4.3% 26-50% Impervious 20,573 13.8% 1,607 3.2% 22,180 11.1% 51-75% Impervious 4,148 2.8% 717 1.4% 4,866 2.4% 76-100% Impervious 2,343 1.6% 186 0.4% 2,529 1.3% Agricultural Land 75,416 50.5% 22,855 45.7% 98,271 49.3% Forest (all types) 8,399 5.6% 7,877 15.7% 16,275 8.2% Open Water 984 0.7% 1,242 2.5% 2,225 1.1% Barren Land 0 0.0% 2 0.0% 2 0.0% Shrubland 280 0.2% 122 0.2% 402 0.2% Grasses/Herbaceous 13,879 9.3% 4,286 8.6% 18,165 9.1% Wetlands (all types) 10,611 7.1% 6,452 12.9% 17,064 8.6% Total 149,436 100.0% 50,038 100.0% 199,474 100.0% 1 Land cover spatial data file provided by MnDNR. The data is a composite of the 2008 MLCCS (Minnesota Land Cover Classification System), which covered primarily the 7-county metro area; and the 2001 NLCD (National Land Cover Data), which covered the outstate areas not included in the 2008 MLCCS.

According to the U. S. Department of Agriculture (USDA) Natural Resources Conservation Service (NRCS) STATSGO soils data, nearly all of the soils in the Vermillion River watershed are characterized as Type B soils, which have a moderate infiltration capacity. There are few, localized regions of soils with high infiltration capacities, or Type A soils, near Farmington and Empire, and the dual hydrologic soil group, Type B/D, along the Mississippi River and south of Hastings (VRWJPO, 2005). The STATSGO soil survey may not be representative of actual conditions. For installation of infiltration practices, soil borings should be taken from the exact location of the proposed site location to assess level of soil filling or disturbance.

The watershed topography consists of hummocky till in the far west, transitioning into rolling till along the south watershed border; the remainder of the watershed is relatively flat outwash and alluvium plane carrying the river over the Hastings Dam (Vermillion Falls) to the Minnesota River (Figure VR-3). The maximum watershed elevation is 1223.0 MSL and the minimum elevation is 752.5 MSL within the monitored area. Within the monitored area 2% of the slopes are considered steep, and an additional 1% is considered very steep (MnDNR, 2011).

Comprehensive Water Quality Assessment of Select Metropolitan Area Streams | Metropolitan Council Vermillion River 5 Edina Mill Pond Mirror Saint Saint Minneapolis Nokomis CrosbyPickerel Ramsey Marys Paul West Pigs Eye Carver Hawkes Lilydale Saint Maplewood Point Pamela Diamond Figure VR-2 Birchcrest Mother Fish Creek St. Croix Kinnickinnic Pond Mendota Paul Troy South Woodbury Afton S Twp. Richfield Legion Duck R Heights T Twp. Heights Cornelia A Mendota Saint

(South) T Newport C R MLCCS-NLCD Hybrid Land Cover Edina Wood Richfield O Augusta Paul

Adams S Sunfish O Rogers River

Edina Hill Pond E 05330920 Schmitt I X Vermillion River Hennepin N Gun Club Falls * N Horseshoe I Hornbean Smith R Pond M River MCES River Monitoring Sites N Falls * in Penn Hohag Saint e Pond Lemay Inver Washington MCES Stream Monitoring Sites Mi Bloomington Paul le Grove 05342000 Bush Cr Park e Oxboro USGS Flow Stations

Cemetery e Heights Marsh O'Leary Marcott k Pond Long Mainstems (Monitored and Unmonitored) Fish Hyland Meadow Blackhawk Denmark River Marcott Cottage Clifton Major Mainstem Tributaries Heritage Bald Grey Cloud Twp. Falls Twp. Hills Pond R Eagan Grove TA Island Twp. Twp. SO Black Monitored Watershed Boundaries E Dog N Quigley Overlook MI N River Mooers Unmonitored Portion of Watersheds Mike's Nine Thomas Grey Cloud Mile Baldwin Slough Marsh McDonough Street Centerlines (NCompass, 2012) Credit O'Brien County Boundary River Burnsville Jensen Area of Willow Main Groundwater City and Township Boundaries Creek Discharge to the Spring Long Kegan Mississippi River Prescott Savage Apple Rebecca Conley Nininger 05344490 Alimagnet Valley Rosemount Twp. Oak MLCCS-NLCD Hybrid Land Cover Earley 05331580 Isabelle 05344500 M Grove Trimbelle 5-10% Impervious Hastings IS Twp. Hanrahan S Twp. Keller Vermillion River I Crystal VR-2.0 SS 11-25% Impervious Horseshoe IP North Coates PI 26-50% Impervious Murphy Lee Branch R Kingsley North Creek Vermillion Krenz 51-75% Impervious Orchard River Mud Hen Unnamed 76-100% Impervious (South Empire r Middle e Portion) Ravenna v Sharp Agricultural Land i Twp. Marion Twp. Muskrat R Credit Twin it (West Marion Lakeville Vermillion Barren Land (rock, mud) d VR-15.6 Marshan e River Bay) (Middle r Farmington Twp. Diamond Forest (all types) C Twp. Bay) VR-20.6 Upper Marion North 05345000 Vermillion Clear Bluff Twp. (East Bay) 05346050 Creek r Brewer Grasses/Herbaceous ve Twp. i Clear R Open Water South n Sturgeon llio

mi Lower Nelson 05344850 Shrubland C r Creek e Rattling r V Springs e Unknown, or No Data d

i t South B er R ran iv Wetlands (open water, forest, shrub and emergent) ch illio n R Goose iv Potters Verm e Buffalo r Hampton Welch New Slough New Rice Trier Twp. Data Source: MnDNR Market Miesville Twp. Eureka Castle Hampton MLSSC/NLCD Hybrid Land Cover Twp. Rock Twp. Douglas Red Wing Vermillion River Twp. Monitored Unmonitored Total k Twp. e N h re Land Cover Class Acres Percent Acres Percent Acres Percent Chub ort B C ra 05355200 g 5-10% Impervious 7,076 4.7% 1,856 3.7% 8,932 4.5% n n k i Elko New c r e h p 11-25% Impervious 5,726 3.8% 2,837 5.7% 8,562 4.3%

e S Scott Market r C 26-50% Impervious 20,573 13.8% 1,607 3.2% 22,180 11.1% C hu Cannon

b bC u r 51-75% Impervious 4,148 2.8% 717 1.4% 4,866 2.4%

h e River C e 76-100% Impervious 2,343 1.6% 186 0.4% 2,529 1.3% Dakota k P er ine iv Agricultural Land 75,416 50.5% 22,855 45.7% 98,271 49.3% Cr Cre ek ee R Forest (all types) 8,399 5.6% 7,877 15.7% 16,275 8.2% Por ter k n Randolph o Open Water 984 0.7% 1,242 2.5% 2,225 1.1% n ek Randolph C re Twp. an k Barren Land 0 0.0% 2 0.0% 2 0.0% hub Cr e k C C e e b e u r Shrubland 280 0.2% 122 0.2% 402 0.2%

h C C Byllesby e Grasses/Herbaceous 13,879 9.3% 4,286 8.6% 18,165 9.1% Creek ll Dut c h Greenvale Cannon e Vasa Wetlands (all types) 10,611 7.1% 6,452 12.9% 17,064 8.6% Waterford Sciota B k Total 149,436 100.0% 50,038 100.0% 199,474 100.0% Webster Twp. d Cree r Falls Cannon Twp. Mu Twp. Twp. e v Featherstone Twp. i R Falls Twp. n o Twp.

Stanton n a

C Twp. C les re ow e le Kn k t it L thCree k Goodhue ea k H e re g C in B r ut Union Sp k l Northfield e er Creek e Bridgewater Sibley r k C e ie e Forest Mud Twp. Marsh ir r Rice ra Warsaw C Belle e Goodhue P l Leon l

Twp. Northfield Twp. e Creek Twp.

B Twp. Dundas Twp. Twp. 0 2 4 6 8 10 lf Creek Wo Circle lf Cre Miles Wo ek Dennison The Vermillion River watershed contains four domestic wastewater treatment plants, including two Class A facilities - the Metropolitan Council’s Empire WWTP and the Elko-New Market WWTP (Figure VR-4, Table VR-2). However in 2008 the Empire WWTP’s outfall was diverted to the Mississippi River north of Hastings. Part of this diversion project included an expansion and upgrade of the Empire WWTP, with a biological phosphorus removal system added in 2006. The Elko-New Market WWTP was decommissioned in 2011, with the wastewater directed to the Empire WWTP. There are no WWTPs in the unmonitored part of the watershed. The watershed has four cooling, potable treatment and dewatering facilities, two industrial wastewater permit holders, and19 industrial stormwater permit holders within the monitored part of the watershed. There is one cooling, potable treatment and dewatering facility and three industrial stormwater permit holders in the unmonitored part.

The Vermillion River watershed has 87 registered feedlots with a total of 12,700 animal units (AUs) in the monitored part of the watershed, and an additional 35 registered feedlots with a total of 5,636 AUs in the unmonitored part. 44 of the feedlots in the monitored area have 100 AUs or more, and 20 feedlots in the unmonitored area have 100AUs or more. The largest feedlot in the watershed is a beef cattle farm with 995 AUs.

Table VR-2: Permitted Domestic Wastewater Treatment Facilities Discharging to the Vermillion River Design Phosphorus Permit #1 Permit Holder Flow Class2 Reduction Other notes3 (mgd) History3 Effluent diverted from Vermillion Met Council - Empire P reduction MN0045845 29 A River to WWTP initiated 06/2006 Mississippi River starting 01/2008 Facility ceased Elko-New Market P reduction MN0056219 0.362 A operation WWTP initiated 03/2006 12/2011 MN0021946 Hampton WWTP 0.101 D NA NA MN0025101 Vermillion WWTP 0.054 C NA NA 1 Facilities with design flow > 1 mgd shown in gray 2 In general, Class A and B WWTPs use mechanical systems with activated sludge that continuously discharge. Class D are stabilization ponds that are allowed to discharge March 1-June 15 (spring discharge) and September 15-December 31 (fall discharge). See Minn. Rule. 9400.0500, Classification of Facilities, for more information. 3 Information provided by MPCA, April 2013. Information was not tabulated for smallest facilities, thus labeled NA.

Comprehensive Water Quality Assessment of Select Metropolitan Area Streams | Metropolitan Council Vermillion River 7 Sanctuary U.S. Lock Wilmes Lake Edith St. Hopkins 05331000 Airport Saint Maplewood Marsh & Dam #1 North Portion Croix Meadowbrook Marsh Paul Valley Harriet Hiawatha Pickerel Pigs Creek Saint Highland Minnehaha Creek 05289800 Lilydale Eye Figure VR-3 Park Pond West Fish Marys Nokomis Carver Hawkes Crosby Saint Creek Point Kinnickinnic Pamela Diamond Troy Pike Woodbury Afton Birchcrest Pond Taft Paul Twp. Twp. Watershed Topography Bredeson Mother Island Marsh Arrowhead Heights Cornelia Richfield Legion Duck Fort Mendota Snelling South Vermillion River Indianhead (South) Wood Richfield Snelling Augusta Heights 05330920 Sunfish Saint Adams Newport Eden (unorg.) Rogers Schmitt Paul River Edina Edina Hill Pond Hennepin Gun Club Prairie Horseshoe Falls * MCES River Monitoring Sites North Smith Anderson Normandale Pond River MCES Stream Monitoring Sites Southwest Hohag Falls * Anderson Penn Inver Washington Nordmyr Pond Lemay Saint USGS Flow Stations Bush Bloomington Grove 05342000 Oxboro Paul Oregon Marsh Heights Stream Mile Markers O'Leary Marcott Park Avenue Pond Long Hyland Nine Mile Blackhawk Fish Denmark Meadow Cottage Mainstems (Monitored and Unmonitored) Heritage Bald Marcott Grey Cloud Twp. Clifton River Creek Eagan Hills Pond Island Twp. Grove Twp. Falls Twp. Unmonitored Watershed Areas Black River Sylvia Dog Quigley Fisher Overlook Monitored Watershed Boundaries Mae Marsh Thomas Mooers Rice Mike's Marsh McDonough Grey Cloud Mi County Boundary O'Brien Slough s Willow sissippi Eagle Credit Jensen Area of Baldwin Creek R City and Township Boundaries Creek River Groundwater iv Main e Shakopee Burnsville Discharge to the r Highways and Other Major Roads Spring Savage LongFarquar Kegan Mississippi River Prescott Rebecca Public Waters Inventory Apple Nininger Conley 05344490 Alimagnet Rosemount 05331580 Valley Twp. Other Rivers and Streams Earley Isabelle 05344500 Oak Grove Lower Trimbelle Prior Hastings 8 7 Twp. Cate's or 9 6 5 Hanrahan Keller 4 Twp. Hidden 11 10 VR-2.0 0 Crystal 12 3 Horseshoe Coates Vermillion 2 1 Elevation Murphy Lee North North Creek Branch 13 River Feet Above Mean Sea Level Krenz Kingsley Vermillion 14 Orchard Empire Mud Hen High : 1594 River 15 Cleary Unnamed Twp. Credit 16 Sharp Spring (South Middle Ravenna River Portion) 17 Muskrat Trenton 1400 Lake Marion Dakota Twp. Twp. 18 Twin Twp. Twp. (West Lakeville VR-15.6 19 Marshan 1200 Bay) 20 26 Vermillion Twp. Diamond Scott Farmington VR-20.6 05345000 22 21 Upper North Kane Marion 27 Clear 05346050 Bluff Twp. 32 29 25 1000 (East Bay) Creek 30 23 Brewer Vermillion Clear 34 33 South Twp. 05344850 800 35 Lower Nelson Sturgeon McMahon Creek Rattling 36 Ver Low : 643 Springs m ll C i io

r 37 n e 39 38 S S d 41 o l 42 40 uth Bran ou ch er g Source: USGS National Elevation Dataset, it Ve iv Welch h R Potters rm on R 1/3 arc-second, 10-meter resolution New 44 43 illi Goose Pickerel iv Twp. e 45 Hampton Wildcat r Market Rice New Slough Twp. r Trier e 46 Miesville v i 50 R Eureka Castle Hampton Mainstem Elevation (Feet Above Mean Sea Level) Vermillion 47 Twp. a Rock Twp. Douglas Br nch Twp. 1300 48 orth C b 49 Cr N hu Cr Twp. Red Wing Cedar ub ee e h k e k Vermillion River Average Slope: 8.3 feet/mile Lake Elko New C Cannon 05355200 River Monitoring Station 1200 Twp. Market gCre C in e Pine re r k ek p Chub Creek S 1100 lle

e B P orter 1000 Cr eek C Randolph hub C reek Randolph 900 Riv k anno n er Twp. r Wheatland ee Greenvale C Byllesby e Dutch r C ek v C re i hu b C Sciota Vasa 800 Twp. Twp. k R Webster d Cree non Twp. u Twp. k n Featherstone Hastings Dam M a e Cannon Twp. Waterford re C 700 C Twp. e ng l Twp. ri t Falls Twp. t

Sp i L Goodhue 600 k Stanton Kno reek e 0.05.010.015.020.025.030.035.040.045.050.0 wle C e s r Twp. C Lonsdale th Creek ea ie H ir River Mile a

Pr r Union e Northfield v Butler Cree i k

k Sibley R e n Mud Marsh re o

Erin n C

l Rice n e

Northfield a Goodhue

Twp. l

Forest k Warsaw C Leon Belle Dundas Twp. e e Twp. re e e B Twp. W lf C e k r Twp. ttl Twp. Creek Twp. o Bridgewater C i L

e i r

Circle Twp. i Dennison a r 0 2 4 6 8 10 P Goodhue Fox Miles Harriet Minneapolis M Pickerel West Highland 05289800 Saint IS R Saint Ramsey Park Pond Diamond Nokomis S I Marys Point Hawkes ISSIPP Lilydale Paul Fish Creek 4 Bredeson Taft Figure VR- Fort Mendota Troy Cornelia Snelling Woodbury (North) Richfield Legion South Newport Afton Twp. (unorg.) Kinnickinnic

Cornelia Richfield Augusta Mendota Sunfish Saint R Public and Impaired Waters and Potential Pollution Sources Edina (South) Adams Wood Twp.

Heights Lake Paul X Hill 05330920 Schmitt I Edina Rogers Vermillion River Pond Hennepin Gun Club Horseshoe O Smith R Bloomington Pond R C River MCES River Monitoring Sites Wright's A T Normandale T Falls * S Penn O Lemay S Saint Washington MCES Stream Monitoring Sites Marsh E Paul Park 05342000 Oregon N Avenue USGS Flow Stations IN O'Leary Marcott Pond M Blackhawk Fish Denmark River Mainstems (Monitored and Unmonitored) Cottage Clifton Falls Heritage Nine Mile Creek Bald Marcott Grey Cloud Twp. Monitored Watershed Boundaries Hills Pond Eagan River Grove Twp. Twp. Island Twp. Black St. Unmonitored Portion of Watersheds Sylvia Dog Quigley Inver Croix Mae Marsh Nine Grove Mooers Mike's Mile Thomas McDonough Heights Industrial Discharges ** Marsh Willow Grey Cloud O'Brien Slough Industrial Stormwater Creek Jensen Area of Baldwin Credit Burnsville Main Groundwater River Discharge to the Nininger Industrial & Individual Wastewater Mississippi River Spring Twp. Long Farquar Kegan Prescott Cooling, Potable Treatment & Dewatering Apple Savage Alimagnet Conley Rebecca 05344490 Empire WWTP Effluent Diversion (1/2008) Valley Rosemount 05344500 05331580 Isabelle Oak Earley Grove Domestic Wastewater Discharges ** Hastings Trimbelle Twp. Twp. Class A Hanrahan Crystal Keller VR-2.0 Class B Horseshoe Coates M Lee IS Murphy S Class C Krenz Kingsley North Creek IS r

e Orchard Dakota Mud Hen S

v I Class D

i Unnamed Empire North Branch P R Vermillion River P (South Vermillion Sharp I t Middle Twp. R Class Unknown i Portion) Twp. Ravenna Muskrat d Marion e Marion Twp. Twin r (West Marshan C (Middle Feedlots with 100 or more animal units ** Credit Bay) VR-15.6 Vermillion Twp. Diamond Bay) Lakeville Farmington Upper 100 - 249 River 05345000 Clear North Bluff Twp. Twp. Marion 250 - 499 (East Bay) VR-20.6 05346050 Creek Brewer 500 - 999 Clear Scott South 1000 or more r 05344850 e Lower iv Sturgeon C R Rattling Impaired Lakes 2014 Draft (MPCA 303(d) List) ** o n Ve r Creek li r il Springs milli e m o

d r n Impaired Streams (2014 Draft MPCA 303(d) List) ** e i S

t l V ou ch g Other Rivers and Streams * R ran h iv Potters South B e Goose Pickerel Lakes and Other Open Water (PWI) * r Rice Wildcat Slough Hampton New Wetlands (PWI) * Castle Trier Miesville New Eureka Rock Twp. Designated Trout Streams * Market Twp. Welch Twp. NCompass Street Centerlines, 2013 Twp. a Douglas Red Wing Br nch N orth C hubC k County Boundaries re Twp. e e Hampton re k Cannon C City and Township Boundaries g Elko New Twp. n River ri p

Market C S Data Sources: * MN DNR, ** MPCA, *** MN DOT

Pine ree 05355200 C k

Chub h

u Extent of Main Map b r k ve e Stearns Isanti C i re Sherburne r R C Cr eek e MISSISSIPPI R Chisago P er e n e

ort l k Randolph o e n Randolph Twp. n B Ca Vasa Wright M IS Washington utch C Sciota Cannon Twp. S Anoka D r Byllesby IS e Greenvale e S r ek I C Twp. Falls P e C b ST CROIXR k Twp. h u P I k R Webster d Cree Mu Cannon Hennepin Twp. ek Stanton re Falls Twp. Ramsey Twin Cities g C Twp. Metropolitan prin S Area sC Goodhue le r w e Featherstone Kn o ek Northfield Twp. McLeod Carver MINNESOTA R Union thCre ek ea H M Northfield Scott Dakota I SS IS S k IP e r Butler Cre P e ek I r e R v

Sibley C k Northfield i Sibley ie R e Mud Marsh ir R Forest e Rice Twp. a Warsaw n r A r Goodhue T P o Leon C O

Twp. e Twp. n 0 1 2 4 6 8 S l Twp. l E Bridgewater a Twp. Belle Dundas N e

C N I Rice lf Cree Twp. B Creek Le Sueur o k M W tle Miles t Goodhue i

lf Cre L Twp. Nicollet Circle Wo ek Dennison Wabasha Water Quality Impairments The Vermillion River watershed contains 17 stream reaches that are included on the MPCA 2014 303d (Impaired Waters) list (Figure VR-4, Table VR-3). This includes six reaches of the Vermillion River, from the headwaters in New Market Township to the confluence with the Mississippi River, and 11 reaches of smaller tributary streams that feed the Vermillion River. Most of the Vermillion River watershed impairments are biological (Fecal Coliform, E. coli, and macroinvertebrate and fish bioassessements); the exceptions are mercury in fish tissue (all have approved plans), PCBs in fish tissue, and impairments for dissolved oxygen and temperature.

Comprehensive Water Quality Assessment of Select Metropolitan Area Streams | Metropolitan Council Vermillion River 10 Table VR-3: Impaired Reaches in the Vermillion River Watershed as Identified on the MPCA 2014 Impaired Waters List Affected Approved Needs Reach Name Reach Description Reach ID Use(s)1 Plan Plan2,3 Headwaters to Unnamed creek 07040001-546 AQR --- E.coli* Unnamed cr Headwaters to Unnamed creek 07040001-542 AQR --- FC* Unnamed cr Unnamed cr to Unnamed creek 07040001-548 AQR --- E.col*i Unnamed cr Unnamed cr to Unnamed creek 07040001-527 AQR --- FC* Vermillion R Unnamed creek Unnamed cr to (Vermillion 07040001-545 AQR, AQL --- FC*, DO Vermillion R River Tributary) Unnamed creek Unnamed cr to T114 (Vermillion 07040001-668 AQR --- FC* R20W S25, east line River Tributary) Unnamed creek Unnamed cr to T114 (Vermillion R19W S19, south 07040001-670 AQR --- E.coli* River Tributary) line Unnamed creek T114 R19W S30, (Vermillion north line to 07040001-671 AQR --- FC* River Tributary) Unnamed cr T114 R18W S21, AQR, AQL, Vermillion River west line to 07040001-692 FC, HgF F-IBI AQC Hastings Dam Headwaters to T113 Vermillion River 07040001-516 AQR, AQC HgF E.coli* R20W S8, east line T114 R19W S30, AQR, AQL, Vermillion River south line to S Br 07040001-507 FC, HgF M-IBI, F-IBI AQC Vermillion R Vermillion R/Vermillion Slough, Vermillion River 07040001-504 AQC, AQL HgF, T PCBF Hastings Dam to Mississippi R T113 R20W S9, M-IBI, FC*, west line to T114 AQR, AQL, Vermillion River 07040001-517 HgF F-IBI, DO, R19W S31, north AQC T* line S Br Vermillion R to Vermillion River T114 R18W S20, 07040001-691 AQC, AQC HgF --- east line

Comprehensive Water Quality Assessment of Select Metropolitan Area Streams | Metropolitan Council Vermillion River 11 Vermillion Headwaters to T113 River, South 07040001-706 AQR --- FC* R19W S2, east line Branch T113 R19W S1, Vermillion west line to T114 River, South 07040001-707 AQR --- FC* R18W S29, north Branch line 1 AQR = Aquatic Recreation; AQL = Aquatic Life; AQC = Aquatic Consumption 2 FC = Fecal Coliform; T = Turbidity; F-IBI = Fisheries Bioassessments; DO = Dissolved Oxygen; M-IBI = Aquatic Macroinvertebrates Bioassessments; PCBF = PCB in Fish Tissue 3 * = Is addressed in the 2014 DRAFT Vermillion River Watershed TMDLs (MPCA et al., 2014)

The Vermillion River watershed contains 5 lakes that are included on the MPCA 2014 303(d) list (Figure VR-4, Table VR-4). Most of the lakes have approved plans for their impairments. The remaining two lakes, Alimagnet and Unnamed, still need plans to address their nutrient impairments.

Table VR-4: Impaired Lakes in the Vermillion River Watershed as Identified on the MPCA 2014 Impaired Waters List Affected Approved Needs Lake Name Lake ID Use(s)1 Plan2 Plan2,3 Alimagnet 19-0021-00 AQR --- Nutrients* Farquar 19-0023-00 AQR Nutrients --- Long 19-0022-00 AQR Nutrients --- Marion (East Bay) 19-0026-01 AQC HgF --- Marion (Middle Bay) 19-0026-02 AQC HgF --- Marion (West Bay) 19-0026-03 AQC HgF --- Unnamed 19-0349-00 AQR --- Nutrients* 1 AQC = Aquatic Consumption; AQR = Aquatic Recreation 2 HgF = Mercury in Fish Tissue; 3 * = Is addressed in the 2014 DRAFT Vermillion River Watershed TMDLs (MPCA et al., 2014)

The VRWJPO is currently working with the MPCA to develop the Vermillion River Watershed Restoration and Protection Strategy, or WRAPS. This process will allow the VRWJPO to create a plan to address the many impairments within the watershed. As a part of the process many reports have been produced such as, biological stressor identification (Wenck Associates, Inc. 2013), watershed monitoring and assessment (MPCA, 2014b), and TMDLs (MPCA et al., 2014). Hydrology MCES has monitored flow of the Vermillion River at Hastings (VR 2.0) since 1995. Flow measurements were collected at 15-minute intervals and converted to daily averages. The hydrograph of the Vermillion River (Figure VR-5), which displays daily average flow, daily

Comprehensive Water Quality Assessment of Select Metropolitan Area Streams | Metropolitan Council Vermillion River 12 precipitation, and the flow associated with grab and composite samples, indicates the variation in flow rates from season to season and from year to year, and the effect of precipitation events on flow.

The MCES sampling program specifies collection of baseflow grab samples between events and event-based composites. The hydrograph indicates samples were collected during most events and that baseflow was also adequately sampled. Due to technical issues with the monitoring station, only grab samples have been collected since 2007.

The Vermillion River has both cool water reaches (headwaters to Empire) and warm water reaches (Empire to Hastings). The cool reaches have a groundwater source which helps to lower the water temperature and provide temperatures suitable for trout habitat. The warm reach flows are primarily derived from surface waters. Due to groundwater contributions, the Vermillion River maintains a baseflow and typically does not fully freeze during the winter months or run dry during prolonged periods with little precipitation.

The Vermillion River hydrograph is characteristic of a moderate prairie river system. Generally, the storm event daily average flows were less than 1,100 cubic feet per second (cfs); five spring rains or snowmelt-driven events exceeded this level in 1998, 2002, 2003, and 2012. Of those events, the highest recorded daily average flow in the Vermillion River - 2,035 cfs - occurred in 1998. The mean average daily flow is much lower - 139 cfs - which is higher than the median average daily flow of 99 cfs. This highlights the effect of larger events on the mean average daily flow value.

Analysis of the duration of daily average flows indicates the upper 10th percentile flows for period 1995-2012 ranged between approximately 267 to 2,035 cfs, while the lowest 10th percentile flows ranged from 21 to 43 cfs (See Figure VR-15 in the Flow and Load Duration Curves section of this report).

The variations in flow are partially driven by seasonal patterns in precipitation as well as by variation in frequency of intense storm events. However, nearly half of the precipitation most likely does not affect the stream as surface runoff. During the years 1995-2012, the median annual runoff ratio was 0.25, indicating 75% of the precipitation either infiltrated the soils, evaporated off of the surface, was evapotranspirated by vegetation, or was stored in watershed wetlands, lakes, and ponds.

As mentioned in the stream and watershed description, the primary Vermillion River soil type (Type B) facilitates moderately high infiltration which may extract much of the overland flow. Over time the infiltrated precipitation recharges the groundwater, which in turn feeds into the stream. This potential flow regime may account for the slight lag between the precipitation and rise in the flows and the nonlinear response between the magnitude of flows and the amount of precipitation (Figure VR-5).

An additional complication in interpreting Vermillion River flow data is the influence of the effluent discharged from the Empire WWTP. The WWTP was commissioned in 1979 and discharged to the river until 2008, when the effluent was diverted to the Mississippi River. During periods of low flow, the effluent volume comprised a significant portion of the river flow, at times exceeding 50% (Figure VR-6).

Comprehensive Water Quality Assessment of Select Metropolitan Area Streams | Metropolitan Council Vermillion River 13 Figure VR-5: Vermillion River Daily Average Flow, Sample Flow, and Precipitation, 1995-2012* 3,300 0.0

2,750 2.0

2,200 4.0

1,650 6.0

1,100 8.0 (in) Precipitation Daily Daily Average Flow(cfs) Average Daily

550 10.0

0 12.0 12 11 10 09 08 07 06 12 05 11 04 10 03 09 02 08 01 07 00 06 99 05 98 04 97 03 96 02 95 01 00 99 98 97 96 95 ------Jul Jul Jul Jul Jul Jul Jul Jul Jul Jul Jul Jul Jul Jul Jul Jul Jul Jul Jan - Jan - Jan - Jan - Jan - Jan - Jan - Jan - Jan - Jan - Jan - Jan - Jan - Jan - Jan - Jan - Jan - Jan -

Daily Average Flow Event Composite Sample Grab Sample Daily Precipitation

*Precipitation record was acquired from NWS COOP stations: 213567-Hastings Dam 2 and 217107-Rosemount Agr Exp Stn Figure VR-6: Vermillion River at Empire Daily Flow, Empire WWTP Effluent Flow, and WWTP Percent of Flow, 2000-2012

Vermillion River at Empire (USGS) Daily Flow, Empire WWTP Effluent, and WWTP Percent of Flow, 2000-2012 400 60%

300 30%

200 0% WWTP WWTP Percent of Flow (%) Flow (cfs)

100 -30%

0 -60% 2003 2004 2000 2001 2002 2005 2006 2007 2008 2009 2010 2011 2012

Vermillion River at Empire Empire WWTP WWTP percent of total flow

There have been many hydrologic studies of the Vermillion River since the 1970’s, primarily focused on flood hazard planning within the watershed:

• 1974 – TR-20 Hydrologic Evaluation Study (USDA, 1974)

• 1989 – Eugene A. Hickock and Associates: Watershed Management Organization Study

• 1995 – Hydrology and Relation of Selected Water-Quality Constituents to Selected Physical Factors in Dakota County, Minnesota, 1990-1991 (Almendinger and Mitton, 1995)

• 1998 – HEC-1 Model Study (USACE, 1998)

• 2002 – Watershed Management Organization Volume Study (Montgomery-Watson- Harza, 2002)

• 2003 -- Hastings Area Nitrate Study Final Report. (Dakota County, 2003)

• 2009 – Vermillion River Hydrologic Study of Existing Conditions (Barr Engineering Company, 2009)

Comprehensive Water Quality Assessment of Select Metropolitan Area Streams | Metropolitan Council Vermillion River 15 is filled with later glacial outwash) is greater than 500 feet, in contrast to a depth of less than 50 feet outside of the buried valley. The buried valley provides a conduit for river water to flow downward to surficial aquifers. Dakota County’s Hastings Area Nitrate Study (Dakota County, 2003) indicates that the quality of the Vermillion River in the vicinity of the buried valley may affect shallow individual household drinking water wells downstream near the city of Hastings (Figure VR-7). Conversely, the geology in the vicinity of the South Branch of the Vermillion River drives the discharge of both deep and shallow groundwater to the river (Almendinger and Mitton, 1995). Dakota County has found elevated nitrate levels in the South Branch, likely driven by both discharge of agricultural runoff and high nitrate groundwater to the river (T. Thiel, Dakota County, personal communication, 2015).

Figure VR-7: Groundwater and surface water elevations between the cities of Vermillion and Hastings (courtesy of Dakota County)

Vulnerability of Stream to Groundwater Withdrawals Regional analysis (Metropolitan Council, 2010) of hydrogeologic conditions in the seven-county metropolitan area suggests that some surface water features are in direct connection with the underlying regional groundwater flow system and may be impacted by groundwater pumping. While regional in nature, this analysis serves as a screening tool to increase awareness about the risk that groundwater pumping may have for surface water protection and to direct local resources toward monitoring and managing the surface waters most likely to be impacted by groundwater pumping. Additional information, including assumptions and analytical methodologies, can be found in the 2010 report.

To assess the vulnerability of the Vermillion River watershed to groundwater withdrawals, MCES staff examined spatial datasets of vulnerable stream segments and basins created as part of the 2010 regional groundwater analysis. All of the groundwater-fed reaches and tributaries of the Vermillion River (generally, west of the township of Empire) were identified as potentially vulnerable. Additionally, all of the basins within the western portion of watershed

Comprehensive Water Quality Assessment of Select Metropolitan Area Streams | Metropolitan Council Vermillion River 16 were identified as vulnerable to groundwater withdrawals, including Rice Lake and Lake Marion, plus a number of surrounding smaller unnamed wetlands.

MCES is continuing to evaluate the effects of groundwater withdrawal on surface waters, including updating analyses with the best available data and linking results to predictive groundwater modeling and the comprehensive planning process involving local communities. Pollutant Loads The U.S. Army Corps of Engineers program Flux32 (Walker, 1999) was used to convert daily average flow, coupled with grab and event-composite sample concentrations, into annual and monthly loads and flow-weighted mean concentrations. Loads were estimated for total suspended solids (TSS), total phosphorus (TP), total dissolved phosphorus (TDP), nitrate (NO3), ammonia (NH3), and chloride (Cl) for each year of monitored data in the Vermillion River (1995- 2012).

The purpose of this report is to assess and summarize data collected at stream outlet stations (in this case, WOMP station VR2.0, Vermillion River near Hastings). MCES also operates two stations, VR20.6 (near city of Farmington) and VR15.6 (near city of Empire), which bracket the Empire WWTP effluent discharge pipe, as part of its river monitoring program. Pollutant loads for those two stations are available, but will not be discussed in this report.

Figures VR-8 to VR-11 illustrate annual loads at the Vermillion River near Hastings (VR2.0) expressed as mass, as flow-weighted mean (FWM) concentration, as mass per unit of area (lb/ac), and as mass per unit of area per inch of precipitation (lb/ac/in), as well as three hydrological metrics (annual average flow rate, depth of flow (annual flow per unit area), and precipitation depth coupled with runoff ratio). A later section in this report (Comparison with Other Metro Area Streams) offers graphical comparison of the Vermillion River loads and FWM concentrations with the other MCES-monitored metropolitan area tributaries.

The first charts in Figures VR-8 and VR-9 plot the annual flows from 1995-2012. The flow metrics indicate small year-to-year variations in annual flow rate, as expected from a groundwater fed stream. The highest average annual flow, and thus the highest volume of flow, occurred during 2002 (approximately 283 cfs average annual flow); the lowest average annual flow and lowest volume of flow occurred in 2009 (approximately 49.5 cfs average annual flow). The mean average annual flow was 139 cfs, which is close to the median average annual flow of 132 cfs, suggesting the annual flows were evenly distributed around the mean annual flow.

The annual mass loads for all of the parameters exhibit significant year-to-year variation, indicating the influence of precipitation and surficial flowpaths transporting pollutants within the watershed to the stream, as well as the influence of variable pollutant loads discharged by the Empire WWTP (VR-8). Both TP and TDP loads show a significant drop after 2006, which corresponds with the implementation of biological phosphorus (Bio-P) removal at the Empire WWTP – a process intended to reduce the amount of phosphorus in the effluent. Similarly, there appears to be a reduction in Cl loading after 2007, which corresponds with the 2008 diversion of the Empire WWTP effluent to the Mississippi River.

The annual FWM concentrations reinforce and emphasize the observations from the annual mass loads (Figure VR-9). The pollutant FWM concentrations fluctuate year-to-year, and were likely influenced by the frequency, magnitude, timing, and the routing of precipitation. The TP and TDP FWM concentrations exhibited a decrease after 2006, and chloride concentration

Comprehensive Water Quality Assessment of Select Metropolitan Area Streams | Metropolitan Council Vermillion River 17 decreased after 2007 (likely due to diversion of the Empire WWTP effluent from the Vermillion River to the Mississippi River). The NH3 FWM concentrations showed two peaks - in 2003 and 2007 - corresponding with large snowmelt or spring rain events. It is widely accepted that soil microbes are highly active under insulating snows, accumulating large stores of NH3 in the soils (Brooks et al., 2011). Snowmelt events produce a large volume of water that flows over the thawed soils, potentially transporting NH3 into the stream.

Figures VR-10 and VR-11 present the areal- and precipitation-weighted loads, respectively. These graphics are presented to assist local partners and watershed managers, and will not be discussed here.

The Flux32 loads and FWM concentrations were also compiled by month to allow analysis of time-based patterns in the loads in the Vermilion River (Figures VR-12 and VR-13). The results for each month were expressed in two ways: the monthly results for the most recent year of data (2012 for the Vermillion River) and the monthly average for 2003-2012 (with a bar indicating the maximum and minimum value for that month).

In general, the highest mass loads of all monitored pollutants in the Vermillion River occurred in March through June each year, likely due to effects of snow melt and spring rains. In 2012, the peak water volume and pollutant loads occurred in June.

The TSS FWM concentrations show similar patterns as the loads, highlighting the relationship between higher flows and higher suspended sediments. The TP, TDP, and NO3 FWM concentrations exhibited a very slight reduction during June through August, most likely attributable to biological uptake. The Cl FWM concentration was the highest during the late winter/early spring months, suggesting the influence of road salts.

Comprehensive Water Quality Assessment of Select Metropolitan Area Streams | Metropolitan Council Vermillion River 18 Cl (lb) NH3 (lb) NO3 (lb) TDP (lb) TP (lb) TSS (lb) Annual flow (cfs) 10,000,000 20,000,000 30,000,000 40,000,000 10,000,000 20,000,000 30,000,000 40,000,000 50,000,000 1,000,000 1,500,000 2,000,000 2,500,000 500,000 100,000 150,000 200,000 250,000 100,000 150,000 200,000 250,000 100,000 200,000 300,000 400,000 50,000 50,000 0 0 0 0 0 0 100 200 300 0 *TSS, TP, andTDPsamplingbegan in1995,NO3andNH3began in1998,andClbegan 2001. Bars represent 95% confidence intervals ascalculatedinFlux32. Bars represent 95%confidenceintervals effluentfromtheVermillionEmpire WWTP begandiverting River toMississippi River inJanuary2008. 9919 9319 9719 0120 0520 092011 2009 2007 2005 2003 2011 2001 2009 1999 2007 1997 2005 1995 2003 1993 2011 2001 1991 2009 1999 1989 2007 1997 2005 1995 2003 1993 2011 2001 1991 2009 1999 1989 2007 1997 2005 1995 2003 1993 2011 2001 1991 2009 1999 1989 2007 1997 2005 1995 2003 1993 2011 2001 1991 2009 1999 1989 2007 1997 2005 1995 2003 1993 2011 2001 1991 2009 1999 1989 2007 1997 2005 1995 2003 1993 2001 1991 1999 1989 1997 1995 1993 1991 1989 Figure VR−8 Annual MassLoad : VermillionRiver* Cl (mg/l) NH3 (mg/l) NO3 (mg/l) TDP (mg/l) TP (mg/l) TSS (mg/l) Annual flow (cfs) 0.05 0.15 0.25 100 200 300 100 100 0.2 0.4 0.6 20 40 60 80 20 40 60 80 0.1 0.2 0.2 0.4 0.6 0.8 0 Annual Flow−Weighted MeanConcentration 0 0 0 0 0 2 4 6 8 0 *TSS, TP, andTDPsamplingbegan in1995,NO3andNH3began in1998,andClbegan 2001. Empire WWTP began diverting effluentfromtheVermillionEmpire WWTP begandiverting River toMississippi River inJanuary2008. 9919 9319 9719 0120 0520 092011 2009 2007 2005 2003 2011 2001 2009 1999 2007 1997 2005 1995 2003 1993 2011 2001 1991 2009 1999 1989 2007 1997 2005 1995 2003 1993 2011 2001 1991 2009 1999 1989 2007 1997 2005 1995 2003 1993 2011 2001 1991 2009 1999 1989 2007 1997 2005 1995 2003 1993 2011 2001 1991 2009 1999 1989 2007 1997 2005 1995 2003 1993 2011 2001 1991 2009 1999 1989 2007 1997 2005 1995 2003 1993 2001 1991 1999 1989 1997 1995 1993 1991 1989 Figure VR−9 : VermillionRiver* Cl (lb/acre) NH3 (lb/acre) NO3 (lb/acre) TDP (lb/acre) TP (lb/acre) TSS (lb/acre) Precipitation and runoff (in) Precipitation Runoff 100 150 200 250 100 150 200 250 0.5 1.5 0.2 0.4 0.6 50 50 0.5 1.5 10 20 30 40 50 10 15 0 0 0 1 0 0 0 5 0 1 2 *TSS, TP, andTDPsamplingbegan in1995,NO3andNH3began in1998,andClbegan 2001. Empire WWTP began diverting effluentfromtheVermillionEmpire WWTP begandiverting River toMississippi River inJanuary2008. 9919 9319 9719 0120 0520 092011 2009 2007 2005 2003 2011 2001 2009 1999 2007 1997 2005 1995 2003 1993 2011 2001 1991 2009 1999 1989 2007 1997 2005 1995 2003 1993 2011 2001 1991 2009 1999 1989 2007 1997 2005 1995 2003 1993 2011 2001 1991 2009 1999 1989 2007 1997 2005 1995 2003 1993 2011 2001 1991 2009 1999 1989 2007 1997 2005 1995 2003 1993 2011 2001 1991 2009 1999 1989 2007 1997 2005 1995 2003 1993 2001 1991 1999 1989 1997 1995 1993 1991 1989 Figure VR−10 Annual Areal−Weighted Load : VermillionRiver* Cl (lb/acre/inch) NH3 (lb/acre/inch) NO3 (lb/acre/inch) TDP (lb/acre/inch) TP (lb/acre/inch) TSS (lb/acre/inch) Runoff Ratio 0.005 0.015 0.025 0.01 0.02 0.03 0.01 0.02 0.03 0.04 0.05 0.06 0.02 0.04 0.06 0.08 0.2 0.4 0.6 0.8 0.2 0.4 0.6 0.8 0 2 4 6 0 2 4 6 8 0 0 0 0 0 1 Annual Precipitation−Weighted ArealLoad *TSS, TP, andTDPsamplingbegan in1995,NO3andNH3began in1998,andClbegan 2001. Empire WWTP began diverting effluentfromtheVermillionEmpire WWTP begandiverting River toMississippi River inJanuary2008. 9919 9319 9719 0120 0520 092011 2009 2007 2005 2003 2011 2001 2009 1999 2007 1997 2005 1995 2003 1993 2011 2001 1991 2009 1999 1989 2007 1997 2005 1995 2003 1993 2011 2001 1991 2009 1999 1989 2007 1997 2005 1995 2003 1993 2011 2001 1991 2009 1999 1989 2007 1997 2005 1995 2003 1993 2011 2001 1991 2009 1999 1989 2007 1997 2005 1995 2003 1993 2011 2001 1991 2009 1999 1989 2007 1997 2005 1995 2003 1993 2001 1991 1999 1989 1997 1995 1993 1991 1989 Figure VR−11 : VermillionRiver* Figure VR−12: Vermillion River Mass Load by Month Most Recent Year (2012) of Data Compared to 2003−2012 Average

2012 2003−2012 Average Barbell indicates minimum and maximum 800 values between 2003 and 2012. 600 ● 400 ● ● ● ● ● ● ● ● 200 ● ● ● ● ● ● ● ● ● ● ● ● ● ● ●

Monthly Flow (cfs) Monthly Flow 0