National Lakes Assessment 2012

Lake specific reports: Lakes on the Tamarac National Wildlife Refuge This is part of a series based on Minnesota’s participation in United States Environmental Protection Agency’s 2012 National Lakes Assessment

July 2014

Authors Principal author: Steve Heiskary

Contributors/acknowledgements Minnesota’s 2012 National Lakes Assessment (NLA) was led by Minnesota Pollution Control Agency’s (MPCA) Water Quality Monitoring Unit. A total of 150 lakes were sampled during summer 2012 in this effort. Team leads for the survey, which included responsibility for field reconnaissance, assembling and purchasing needed equipment, office logistics, and sampling of the lakes was led by Pam Anderson, Jesse Anderson, Kelly O’Hara, Lee Engel, Dereck Richter, and Steve Heiskary. Other staff assisting with sampling included: Amy Garcia, Courtney Ahlers-Nelson, Mike Kennedy and Andrew Swanson. Student workers Will Long and Ben Larson also assisted with the sampling. In addition to MPCA staff, Minnesota Department of Natural Resources, US Forest Service, and Native American Band natural resources staff were instrumental in support of sampling and reconnaissance for many of the lakes in this survey. Report Author: Steven Heiskary Pictures on front cover are examples of lakes sampled in this 150-lake survey effort.

Minnesota Pollution Control Agency 520 Lafayette Road North | Saint Paul, MN 55155-4194 | www.pca.state.mn.us | 651-296-6300 Toll free 800-657-3864 | TTY 651-282-5332

This report is available in alternative formats upon request, and online at www.pca.state.mn.us .

Document number: wq-nlap1-10 Map of lakes included in Minnesota’s 2012 National Lakes Assessment

Contents

National Lakes Assessment Overview ...... 1

Flat Lake, Becker County (DOW 3-0242, NLA12_MN-120) ...... 2

Unnamed Lake Becker County (DOW 3-0236, NLA12_MN-281) ...... 5

National Lakes Assessment Overview Minnesota routinely participates in the U.S. Environmental Protection Agency’s (EPA) national random surveys of lakes, streams, wetlands, and estuaries. These surveys occur on a rotating five-year basis. In the first National Lakes Assessment (NLA) in 2007, Minnesota received 42 lakes as a part of the national draw and added eight lakes to allow for state-based assessment. Several partnerships were established to help conduct the survey and prominent partners included Minnesota Departments of Natural Resources and Agriculture and the US Forest Service (Superior National Forest). With aid of these partners, there were several significant add-ons to the national study. In 2012, these same partners and collaborations with the Red Lake and White Earth Bands contributed to a successful survey of Minnesota’s lakes. Notable add-ons in 2012 included pesticides, emerging contaminants, and zooplankton. These brief reports address the two lakes in the Tamarac Wildlife Refuge that were included in the 2012 NLA: Flat Lake (3-0242, MN-120) and Unnamed Lake (3-0236, MN-281).

Study design In the 2012 NLA, Minnesota received 42 lakes and added 8 lakes from the overdraw pool to yield 50 lakes, which allows for statistically based condition estimates for Minnesota’s lakes. All 50 lakes followed the national protocols that included water chemistry, algae, zooplankton and sediment core collection, and physical-habitat assessment. Further details are available at the EPA site http://water.epa.gov/type/lakes/lakessurvey_index.cfm. In addition, Minnesota Pollution Control Agency (MPCA) added 100 lakes from the overdraw list, to allow for ecoregion-based assessments for the three aggregated ecoregions that comprise Minnesota: Northern Lakes and Forests (NLF) and Northern Minnesota Wetlands, Eastern Temperate Forests (Central Hardwood Forest & Driftless Area), and Great Plains (Western Corn Belt Plains, Northern Glaciated Plains, & Red River Valley). Water chemistry, dissolved oxygen and temperature profiles, Secchi, blue-green algal toxin microcystin, pesticide triazine assay, and zooplankton samples were collected from each of these lakes. This 150-lake frame provides comprehensive and representative coverage of Minnesota lakes.

Lake-specific reports While the primary emphasis of the NLA is to statistically-describe the condition of lakes at national, regional, and state scales, the MPCA provides lake-specific reports for a subset of the 2012 NLA lakes. These reports serve a variety of purposes as follows: · Response to request from landowners or other entities that have provided access to lakes and are interested in learning more about the lake. · Provided for lakes within reservation boundaries, forest service property, or other areas where collaborators may be interested in NLA results. · Provided for all 2007 NLA lakes re-sampled in the 2012 survey. These reports will compare results among the two surveys and allow for observations on trends. The individual reports include summary statistics on lake morphometry, watershed area, and land use composition (2006 National Land Cover Dataset). Basic water chemistry and comparisons to ecoregion norms and water quality standards are made when appropriate. A brief narrative is provided for each lake as well. These reports generally do not include biological data, sediment core, nearshore assessments, pesticides, or emerging contaminant information as these will be addressed in topic specific reports that will be posted at http://www.pca.state.mn.us/qzqh141c.

NLA 2012 Report of the Lakes on the Tamarac National Wildlife Refuge • July 2014 Minnesota Pollution Control Agency 1 Flat Lake, Becker County (DOW 3-0242, NLA12_MN-120)

Background Flat Lake has a very large surface area but is very shallow lake located in Becker County. It has a moderate watershed relative to its surface area (12:1) and land use in the watershed is fairly typical for the NLF ecoregion. The entire lake is considered littoral and submergent and emergent plants were evident throughout the lake. Flat was part of the 2007 NLA as well so that data is included for comparison purposes.

Results and discussion Flat Lake was sampled over different timeframes in 2007 and 2012 and that may account for the differences in some of the water chemistry parameters. Water temperature was over 8 C cooler in 2012 as compared to 2007. The lake was well-mixed and well-oxygenated from top to bottom. The trophic status parameters: total phosphorus (TP), chlorophyll-a, and Secchi are indicative of mesotrophic status. TP was lower in 2012 as compared to 2007 and chlorophyll-a was lower as well. Secchi was about twice as deep in 2012 as compared to 2007. These measures are all within or below the typical range for the NLF ecoregion. These measures are also well within the water quality standards for NLF lakes as well. Nitrogen measurements were in the typical range as well. The water is quite clear based on the color and dissolved organic carbon values and indicative of minimal inputs from wetland and forest runoff. The alkalinity, conductivity, calcium, and magnesium values indicate moderately hard water and no significant difference is evident between the two years. Sulfate and chloride levels are low, which in the case of chloride suggests minimal amounts of salt enter the lake from the lake’s watershed. The amount of algae was very low in 2012 based on chlorophyll-a. The blue-green algal toxin, microcystin, was below or just above the reporting limit (RL) in 2012 and was above the RL in 2007. The 2012 values are very low and present no risk, while the 2007 values would be considered very low risk. The MPCA also collected samples for measurement of various emerging contaminants (EMC) and pesticides from the 50 national lakes in the study. Of the numerous EMC tested for, four were detected at low levels: DEET (a personal care product), Amitriptyline and Sulfamethizole (pharmaceuticals), and Androstenedione (hormone). DEET was the most common contaminant found across the study with detections in 75% of the lakes tested. Androstenedione was found in about 30% of the lakes. Further details on this study and information on these contaminants may be found in a MPCA report located at http://www.pca.state.mn.us/index.php/view-document.html?gid=19427. Pesticide samples were analyzed at the Minnesota Department of Agriculture (MDA) laboratory. Three pesticides were detected, but at very low levels. These pesticides, or their degradate products, were as follows: 2,4-D, Atrazine, and Hydroxyatrazine. Since there is minimal cultivated and pastured land use in the watershed, atmospheric deposition may be a possible mode of transport to the lake. Further details on this testing are available in a MDA report that may be accessed from the MPCA web page http://www.pca.state.mn.us/qzqh141c.

NLA 2012 Report of the Lakes on the Tamarac National Wildlife Refuge • July 2014 Minnesota Pollution Control Agency 2 In summary, Flat Lake appears to be unchanged between the two time periods and the differences that do exist can be attributed to the different timeframe of the sample collection. It has very good water quality; however, it is quite sensitive because of its shallowness. It can be considered to be in a “clear water phase” that is characterized by abundant submerged and emergent macrophytes. Lake and watershed characteristics

Lake Metric English Lake area 743 hectares 1,835 acres Lake maximum depth 6.4 meters 21 feet Lake mean depth 1.2 meters 4.0 feet Watershed area (total) 8,780 hectares 21,686 acres Watershed: lake ratio 12:1 Ecoregion: Northern Lakes & Forests (NLF)

Land use composition for total watershed including the lake, based on 2006 NLCD.

NLF typical land Land use Lake % use %

Developed 1 0-7 Cultivated (Ag) 0 <1 Pasture & open 3 0-6 Forest 72 54-81

Water & wetland 25 14-31

NLA 2012 Report of the Lakes on the Tamarac National Wildlife Refuge • July 2014 Minnesota Pollution Control Agency 3

Flat Lake 2007 and 2012 NLA visits as compared to typical range for NLF ecoregion reference lakes and water quality standards (WQS). Ecoregion range and standards are based on summer-mean values.

Parameter 2007 (EPA) 2012 (MDH) NLF WQS Date 8/7/2007 6/12/2012 Temperature C 22.0 14.1 Total Phosphorus (µg/L) 24 <10 14 - 27 30 Chlorophyll (µg/L) 9.4 2.9 4 - 10 9 Secchi Disk (meters) 1.3 2.5 2.4 - 4.6 2.0 Total Kjeldahl Nitrogen (mg/L) 0.88 0.4 – 0.75 Total Nitrogen (mg/L) 0.83 0.73 Color (Pt-Co Units) 20 10 10 – 35 Dissolved organic carbon (mg/L) 9.7 9.0 pH (SU) 8.8 8.3 7.2 - 8.3 6.5-9.0 Total Suspended Sol. (mg/L) 3.6 < 1 – 2

NLA 2012 Report of the Lakes on the Tamarac National Wildlife Refuge • July 2014 Minnesota Pollution Control Agency 4 Parameter 2007 (EPA) 2012 (MDH) NLF WQS Conductivity (umhos/cm) 187 241 50 – 250 Alkalinity (mg/L) 130 40 – 140 Calcium (mg/L) 23.9 27.0 Magnesium (mg/L) 15.3 17.4 Sulfate (mg/L) -- <1.0 Chloride (mg/L) 0.6 0.5 0.6 – 1.2 <0.15 RL, <10 Low Microcystin (µg/L) 4.1 0.19 Index 10-20 Mod. Risk WHO Risk Category1 2.7 <0.15 nearshore 20-200 High Risk 1 Guidelines for safe recreational water environments (World Health Organization, 2003) & MDH report limit

Dissolved oxygen and temperature profile for 2012

Unnamed Lake Becker County (DOW 3-0236, NLA12_MN-281)

Background Unnamed Lake is a small lake located in Becker County. It is located within the White Earth Reservation and on the Tamarac Wildlife Refuge. Access was gained through Refuge land. This lake was not part of the national draw so samples were analyzed by Minnesota Department of Health (MDH). The lake is located in the NLF ecoregion, which is aggregated with the Northern Minnesota Wetlands Area ecoregion and referred to as Northern Forests for NLA analysis purposes. Unnamed Lake has a small watershed relative to its surface area. Land use is dominated by forest and wetland land uses, which is typical for the NLF ecoregion. Summary data, watershed map, and graphics are included in the following pages. Submergent and emergent macrophytes were observed during the survey.

NLA 2012 Report of the Lakes on the Tamarac National Wildlife Refuge • July 2014 Minnesota Pollution Control Agency 5 Results and discussion The trophic status parameters: TP, chlorophyll-a, and Secchi are indicative of mesotrophic to mildly eutrophic status. All measures were within the typical range for the NLF ecoregion. All three measures meet or are close to the lake eutrophication standards for the NLF. Total Kjeldahl Nitrogen was near the typical range as well. Unnamed Lake was not stratified on the sample date. The water has low coloration based on the color value and dissolved organic carbon is quite low. The alkalinity, conductivity, calcium, and magnesium values indicate moderately hard water and calcium is the dominant cation. Sulfate and chloride levels are low, which suggests minimal anthropogenic inputs. The amount of algae was moderate, based on chlorophyll-a. The blue-green algal toxin, microcystin, was below the reporting limit at the mid-lake site.

NLA 2012 Report of the Lakes on the Tamarac National Wildlife Refuge • July 2014 Minnesota Pollution Control Agency 6

Lake and watershed characteristics

Lake Metric English Lake area 8 hectares 20 acres Lake maximum depth 1.0 meters 3.3 feet Lake mean depth 0.8 meters 2.6 feet Watershed area (total) 49 hectares 120 acres Watershed: lake ratio 6:1 Ecoregion: Northern Lakes & Forests (NLF)

NLA 2012 Report of the Lakes on the Tamarac National Wildlife Refuge • July 2014 Minnesota Pollution Control Agency 7

Unnamed Lake land use composition based on 2006 NLCD.

NLF typical land Land use Lake % use % Developed 6 0-7 Cultivated (Ag) 0 <1

Pasture & open 6 0-6 Forest 67 54-81 Water & wetland 21 14-31

NLA 2012 Report of the Lakes on the Tamarac National Wildlife Refuge • July 2014 Minnesota Pollution Control Agency 8 Unnamed Lake 2012 NLA visit as compared to typical range for NLF ecoregion reference lakes and water quality standards (WQS). Ecoregion range and standards are based on summer-mean values.

Parameter 2012 (MDH) NLF WQS Date 6/12/2012 Temperature C 20.7 Total Phosphorus (µg/L) 23 14 - 27 30 Chlorophyll (µg/L) 14.6 4 - 10 9 Secchi Disk (meters) >1.0 2.4 - 4.6 2.0 Total Kjeldahl Nitrogen (mg/L) 0.77 0.4 - 0.75 Total Nitrogen (mg/L) Color (Pt-Co Units) 20 10 - 35 Dissolved organic carbon (mg/L) 8.1 pH (SU) 8.3 7.2 - 8.3 6.5 - 9.0 Total Suspended Sol. (mg/L) 5.6 <1 - 2 Conductivity (umhos/cm) 288 50 - 250 Alkalinity (mg/L) 160 40 - 140 Calcium (mg/L) 46.2 Magnesium (mg/L) 12.8 Sulfate (mg/L) 1.4 Chloride (mg/L) <1.0 0.6 - 1.2 <0.15 RL, <10 Low Microcystin (µg/L) Index 10-20 Mod. Risk WHO Risk Category1 <0.015 nearshore 20-200 High Risk 1 Guidelines for safe recreational water environments (World Health Organization, 2003) & MDH report limit

NLA 2012 Report of the Lakes on the Tamarac National Wildlife Refuge • July 2014 Minnesota Pollution Control Agency 9