West Leaf Lake DNR ID:

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1 East Otter Tail County Water Quality Factsheet West Leaf Lake DNR ID: Vitals Physical Characteristics MN Lake ID: Surface area (acres): 700 Zoning Authority: Ottertail Littoral area (acres): 292 Lake Classification: % Littoral area: 42% Major Drainage Basin: Upper Mississippi River Max depth (ft): 53 Latitude/Longitude: / Mean depth (ft): 22 Water Body Type: Public Inlets/Outlets/Accesses: 1/1/1 Invasive Species: None Lakeshed to lake area ratio: 5:1 Total Phosphorus West Leaf Lake is phosphorus limited, which means that algae and aquatic plant growth is dependent upon available phosphorus. Total phosphorus was evaluated in West Leaf Lake in and The data do not indicate much seasonal variability. Most of the results are within the mesotrophic range. There is not a total phosphorus trend at this time. Chlorophyll a Chlorophyll a is the pigment that makes plants and algae green. It is tested in lakes to determine the algae concentration or how green the water is. Chlorophyll a concentrations greater than 10 ug/l are perceived as a mild algae bloom, while concentrations greater than 20 ug/l are perceived as a nuisance. Chlorophyll a was evaluated in West Leaf Lake in and Concentrations reached 10 ug/l most years, which indicates minor algae blooms; little seasonal variability was evident. No trends were present. West Leaf Lake total phosphorus, chlorophyll a, and transparency historical ranges. The arrow represents the range and the black dot represents the historical mean (Primary Site 206). Figure adapted after Moore and Thornton, [Ed.] Lake and Reservoir Restoration Guidance Manual. (Doc. No. EPA 440/ ) Transparency (Secchi Depth) Transparency is how easily light can pass through a substance. In lakes it is how deep sunlight penetrates through the water. Plants and algae need sunlight to grow, therefore they are only found in areas of lakes where the sun penetrates. Water transparency depends on the amount of particles in the water. An increase in particulates results in a decrease in transparency. The annual mean transparency for West Leaf Lake ranges from 8.0 to 12.5 feet; with the annual means remaining near the long-term mean. The West Leaf Lake transparency was slightly better than the long-term mean in 2000 and 2002, and lower in 2007 and There is no transparency trend. Hypereutrophic Eutrophic Mesotrophic Trophic State Index (TSI) Oligotrophic Phosphorus (nutrients), chlorophyll a (algae concentration), and Secchi depth (transparency) are interrelated. As phosphorus increases, there is more food available for algae, resulting in increased algal concentrations. When algal concentrations increase, the water becomes less transparent and the Secchi depth decreases. The results from these three measurements cover different units and 0 ranges and thus cannot be directly compared or averaged. In order to standardize these measurements to make them directly comparable, we convert them to a tropic state index (TSI). The mean TSI for West Leaf Lake is 47; falling into the mesotrophic range (TSI 40-50). These lakes characteristically have moderately clear water most of the summer. Meso means middle, therefore, mesotrophic literally means medium amount of productivity. Mesotrophic lakes are commonly found in central Minnesota and have clear water with algal blooms in late summer. They are also good for walleye fishing. Local association information: the Leaf Lakes Area Association

2 West Leaf Lake OTTER TAIL COUNTY Lake Water Quality Summary West Leaf Lake is less than 1 mile east of Ottertail, MN in Otter Tail County. It covers 700 acres and has an elongated shape. West Leaf Lake has two inlets and one outlet. It is located very high in the Red Eye River Watershed and receives water from a small area. The main inlet is located along the southwest shore. Water flows into West Leaf from Gourd and Grass Lakes. The second inlet drains a small area to the south of the lake. The outlet is along the east shore and drains into Middle and East Leaf Lakes. The Leaf River ties in with Crow Wing River 3 miles north of Staples, MN, and then eventually the Mississippi River. Water quality data have been collected on West Leaf Lake in and (Table 2 3). These data show that the lake is mesotrophic, characteristic of clear water throughout most of the summer and good recreational opportunities (page 9). The Leaf Lakes Area Association includes West, Middle, and East Leaf Lakes. The association is dedicated to informing the public about the impacts facing lakes today. Their website offers detailed information about invasive species, lake aging, lake stewardship, and wildlife protection strategies. They are also a member of the Otter Tail County Coalition of Lake Associations (COLA). Table 1. Location data and physical characteristics for West Leaf Lake. Location Data MN Lake ID: County: Ecoregion: Major Drainage Basin: Otter Tail Northern Central Hardwood Forests Upper Mississippi River Latitude/Longitude: / Invasive Species: None as of 2011 Table 2. Data availability for West Leaf Lake. Data Availability Physical Characteristics Surface area (acres): 700 Littoral area (acres): 292 % Littoral area: 42% Max depth (ft), (m): 53, 16 Inlets: 1 Outlets: 1 Public Accesses: 1 Transparency data Excellent data source from Chemical data Inlet/Outlet data Excellent total phosphorus and chlorophyll a data from and No inlet or outlet data available. Recommendations For recommendations refer to page 19. RMB Environmental Laboratories, Inc. 1 of West Leaf Lake

3 Lake Map Figure 1. Map of West Leaf Lake with 2010 aerial imagery and illustrations of lake depth contour lines, sample site locations, inlets and outlets, and public access points. The light green areas in the lake illustrate the littoral zone, where the sunlight can usually reach the lake bottom allowing aquatic plants to grow. Table 3. Monitoring programs and associated monitoring sites. Programs include National Lake Assessment (NLA), Citizen Lake Monitoring Program (CLMP), Assess of Chemicals of Potential Concern in MN Lake Sediment and Fish (CPO), Clean Water Legacy Surface Water Monitoring (CWL), MN Department of Agriculture Water Quality Monitoring Program (MNDA), and RMB Environmental Laboratory Monitoring Program (RMBEL). Lake Site Depth (ft) Monitoring Programs NLA: CLMP: *Primary Site 50 CPO: 2007; CLMP: ; CWL: 2011; MNDA: 2007; NLA: 2007; RMBEL: , RMB Environmental Laboratories, Inc. 2 of West Leaf Lake

4 Average Water Quality Statistics The information below describes available chemical data for the primary site (202) of West Leaf Lake through The data set is limited, and all parameters with the exception of total phosphorus, chlorophyll a, and Secchi depth, are means for 1 sample in 2007 and 5 samples in Minnesota is divided into 7 ecoregions based on land use, vegetation, precipitation, and geology. The MPCA has developed a way to determine the average range of water quality expected for lakes in each ecoregion. For more information on ecoregions and expected water quality ranges, see page 11. Table 4. Water quality means compared to ecoregion ranges and impaired waters standard. Impaired Parameter Mean Ecoregion Range 1 Waters Standard 2 Interpretation Total phosphorus (ug/l) > 40 3 Chlorophyll a (ug/l) > 14 Chlorophyll a max (ug/l) Secchi depth (ft) < 7 Dissolved oxygen Total Kjeldahl Nitrogen (mg/l) Dimitic See page 9 Results are better than the expected range for the ecoregion. Dissolved oxygen depth profiles show that the deep areas of the lake are anoxic in late summer. 0.7 < Indicates insufficient nitrogen to support summer nitrogeninduced algae blooms. Alkalinity (mg/l) Indicates a low sensitivity to acid rain and a good buffering capacity. Color (Pt-Co Units) Indicates clear water with little to no tannins (brown stain). ph Indicates a hard water lake. Lake water ph less than 6.5 can affect fish spawning and the solubility of metals in the water. Chloride (mg/l) Within the expected range for the ecoregion. Total Suspended Solids (mg/l) Specific Conductance (umhos/cm) Total Nitrogen :Total Phosphorus Indicates low suspended solids and clear water Within the expected range for the ecoregion. 45:1 25:1 35:1 Indicates the lake is phosphorus limited, which means that algae growth is limited by the amount of phosphorus in the lake. 1 The ecoregion range is the 25 th 75 th percentile of summer means from ecoregion reference lakes 2 For further information regarding the Impaired Waters Assessment program, refer to 3 Chlorophyll a measurements have been corrected for pheophytin Units: 1 mg/l (ppm) = 1,000 ug/l (ppb) RMB Environmental Laboratories, Inc. 3 of West Leaf Lake

5 Water Quality Characteristics - Historical Means and Ranges Table 5. Water quality means and ranges for primary sites. Parameters Primary Site 202 Total Phosphorus Mean (ug/l): 19 Total Phosphorus Min: 10 Total Phosphorus Max: 52 Number of Observations: 76 Chlorophyll a Mean (ug/l): 8 Chlorophyll a Min: 1 Chlorophyll a Max: 20 Number of Observations: 74 Site 201 Secchi Depth Mean (ft): Secchi Depth Min: Secchi Depth Max: Number of Observations: Figure 2. West Leaf Lake total phosphorus, chlorophyll a, and transparency historical ranges. The arrow represents the range and the black dot represents the historical mean (Primary Site 202). Figure adapted after Moore and Thornton, [Ed.] Lake and Reservoir Restoration Guidance Manual. (Doc. No. EPA 440/ ) RMB Environmental Laboratories, Inc. 4 of West Leaf Lake

6 Secchi Deapth (ft) Transparency (Secchi Depth) Transparency is how easily light can pass through a substance. In lakes it is how deep sunlight penetrates through the water. Plants and algae need sunlight to grow, so they are only able to grow in areas of lakes where the sun penetrates. Water transparency depends on the amount of particles in the water. An increase in particulates results in a decrease in transparency. The transparency varies year to year due to changes in weather, precipitation, lake use, flooding, temperature, lake levels, etc. The annual mean transparency for West Leaf Lake ranges from 8.0 to 12.5 feet; with the annual means remain near the long-term mean. The transparency was slightly better than the long-term mean in 2000 and 2002 and lower in 2007 and Monitoring should be continued annually at site 202 to track water quality changes. 14 Transparency: Annual Means Site 202 Long-term Mean Figure 3. Annual mean transparency compared to long-term mean transparency (site 202). West Leaf Lake transparency ranges from 4.9 to 20.5 feet at the primary site (202). Figure 4 shows the seasonal transparency dynamics. The maximum Secchi reading is usually obtained in early summer. West Leaf Lake transparency is high in May and June, and then declines through August. The transparency then rebounds in October after fall turnover. This transparency dynamic is typical of a northern Minnesota lake, and are influenced by algae and zooplankton population dynamics, and lake turnover. It is important for lake residents to understand the seasonal transparency dynamics in their lake so that they are not worried about why their transparency is lower in August than it is in June. It is typical for a lake to vary in transparency throughout the summer. RMB Environmental Laboratories, Inc. 5 of West Leaf Lake

7 Secchi Depth (ft) Seasonal Transparency Dynamics Poly. (Pattern) Figure 4. Seasonal transparency dynamics and year to year comparison (Primary Site 202). The black line represents the seasonal pattern of the data. User Perceptions When volunteers collect Secchi depth readings, they record their observations of the water based on the physical appearance and the recreational suitability. These perceptions can be compared to water quality parameters to see how the lake user would experience the lake at that time. Looking at transparency data, as the Secchi depth decreases the perception of the lake's physical appearance rating also decreases. West Leaf Lake was rated as being not quite crystal clear 55% of the time between (site 202). 1% Physical Appearance Rating 1% Crystal clear water 55% Not quite crystal clear a little algae visible 44% 44% Definite algae green, yellow, or brown color apparent 55% 0% High algae levels with limited clarity and/or mild odor apparent 0% Severely high algae levels Figure 5. Physical appearance rating, as rated by the volunteer monitor (site 202). RMB Environmental Laboratories, Inc. 6 of West Leaf Lake

8 Total Phosphorus (ug/l) As the Secchi depth decreases, the perception of recreational suitability of the lake decreases. West Leaf Lake was rated as having very minor aesthetic problems 55% of the time from (site 202). 15% Recreational Suitability Rating 30% 15% Beautiful, could not be better 55% Very minor aesthetic problems; excellent for swimming, boating 30% Swimming and aesthetic enjoyment of the lake slightly impaired because of algae levels 0% Desire to swim and level of enjoyment of the lake substantially reduced because of algae levels 55% 0% Swimming and aesthetic enjoyment of the lake nearly impossible because of algae levels Figure 6. Recreational suitability rating, as rated by the volunteer monitor from (site 202). Total Phosphorus West Leaf Lake is phosphorus limited, which means that algae and aquatic plant growth is dependent upon available phosphorus. Total phosphorus was evaluated in West Leaf Lake in and The data do not indicate much seasonal variability. Most of the results are within the mesotrophic range (Figure 7) Total Phosphorus Eutrophic Mesotrophic Oligotrophic Phosphorus should continue to be monitored to track any future changes in water quality. Figure 7. Historical total phosphorus concentrations (ug/l) for West Leaf Lake. RMB Environmental Laboratories, Inc. 7 of West Leaf Lake

9 Chlorophyll a Chlorophyll a Chlorophyll a is the pigment that makes plants and algae green. It is tested in lakes to determine the algae concentration or how green the water is. Concentrations greater than 10 ug/l are perceived as a mild algae bloom, while concentrations greater than 20 ug/l are perceived as a nuisance. Chlorophyll a was evaluated in West Leaf Lake in and Concentrations reached 10 ug/l most years, which indicates minor algae blooms (Figure 8); little seasonal variability was evident Chlorophyll a Figure 8. Chlorophyll a concentrations (ug/l) for West Leaf Lake Nuisance Algae Minor Algae Dissolved Oxygen Dissolved Oxygen (DO) is the amount of oxygen dissolved in lake water. Oxygen is necessary for all living organisms to survive, except for some bacteria. Living organisms breathe in oxygen that is dissolved in the water. Dissolved oxygen levels of <5 mg/l are typically avoided by game fisheries. West Leaf Lake is a moderately deep lake, with a maximum depth of 53 ft. Dissolved oxygen profiles from 2007 and 2011 indicate that site 202 stratifies in the summer. In July and August game fish will not likely be found below 23 feet, due to the lack of oxygen. Benthic phosphorus samples taken in 2007 and 2011 indicate minor internal loading (16 84 ug/l). Figure 9 illustrates stratification in the summer of 2011 at site 202. This is a representative DO profile for West Leaf Lake. Figure 9. Dissolved oxygen for West Leaf Lake in 2011 at site 202. RMB Environmental Laboratories, Inc. 8 of West Leaf Lake

10 Trophic State Index Phosphorus (nutrients), chlorophyll a (algae concentration), and Secchi depth (transparency) are related. As phosphorus increases, there is more food available for algae, resulting in increased algal concentrations. When algal concentrations increase, the water becomes less transparent and the Secchi depth decreases. The results from these three measurements cover different units and ranges and thus cannot be directly compared or averaged. In order to standardize these three measurements to make them directly comparable, we convert them to a trophic state index (TSI). Table 6. Trophic State Index for site 202 Trophic State Index Site 202 TSI Total Phosphorus 47 TSI Chlorophyll a 51 TSI Secchi 44 TSI Mean 47 Trophic State: Mesotrophic Numbers represent the mean TSI for each parameter. 100 The TSI for West Leaf Lake falls in the mesotrophic range (40 50) (Figure 10). There is fairly good agreement between the TSI for phosphorus, chlorophyll a, and transparency, indicating that these variables are related (Table 6). The transparency TSI is slightly lower than the chlorophyll TSI. This could be due to zooplankton West Leaf Lake grazing on the smaller algae cells, large algae particles dominate the algal community, or loss of rooted vegetation. Hypereutrophic Eutrophic Mesotrophic Mesotrophic lakes (TSI 40 50) are characterized by moderately clear water most of the summer. "Meso" means middle or mid; therefore, mesotrophic means a medium amount of productivity. Mesotrophic lakes are commonly found in central Minnesota and have clear water with algal blooms in late summer (Table 7). They are also good for walleye fishing. Oligotrophic Figure 10. Trophic state index chart with corresponding trophic status. 0 Table 7. Trophic state index attributes and their corresponding fisheries and recreation characteristics. TSI Attributes Fisheries & Recreation <30 Oligotrophy: Clear water, oxygen throughout Trout fisheries dominate the year at the bottom of the lake, very deep cold water Bottom of shallower lakes may become anoxic (no oxygen). Trout fisheries in deep lakes only. Walleye, Cisco present Mesotrophy: Water moderately clear most of the summer. May be "greener" in late summer. No oxygen at the bottom of the lake results in loss of trout. Walleye may predominate Eutrophy: Algae and aquatic plant problems possible. "Green" water most of the year. Warm-water fisheries only. Bass may dominate Blue-green algae dominate, algal scums and aquatic plant problems. Dense algae and aquatic plants. Low water clarity may discourage swimming and boating Hypereutrophy: Dense algae and aquatic Water is not suitable for recreation. plants. >80 Algal scums, few aquatic plants Rough fish (carp) dominate; summer fish kills possible Source: Carlson, R.E A trophic state index for lakes. Limnology and Oceanography. 22: RMB Environmental Laboratories, Inc. 9 of West Leaf Lake

11 Secchi Depth (ft) Trend Analysis For detecting trends, a minimum of 8 10 years of data, with 4 or more readings per season, are recommended. Minimum confidence accepted by the MPCA is 90%. This means that there is a 90% chance that the data are showing a true trend and a 10% chance that the trend is a random result of the data. Only short-term trends can be determined with just a few years of data, because there can be different moisture years, water levels, weather, etc., that affect the water quality naturally. There is enough historical data to perform trend analysis for transparency, total phosphorus, and chlorophyll a on West Leaf Lake (Table 8, Figure 11); the Mann Kendall Trend Analysis was used. Table 8. Trend analysis for West Leaf Lake. Lake Site Parameter Date Range Trend 202 Transparency No Trend 202 Total Phosphorus No Trend 202 Chlorophyll a No Trend 25 West Leaf Lake Transparency Trend Figure 11. Transparency (ft) trend for site 202 from No trend was found for any of the parameters, indicating stable water quality. Transparency monitoring should continue at site 202 so potential trends can be tracked in the future. RMB Environmental Laboratories, Inc. 10 of West Leaf Lake

12 Total Phosphorus (ppb) Chlorophyll-a (ppb) Secchi depth (ft) Ecoregion Comparisons Minnesota is divided into 7 ecoregions based on land use, vegetation, precipitation, and geology (Figure 12). The MPCA has developed a way to determine the average range of water quality expected for lakes in each ecoregion. From , the MPCA evaluated the lake water quality for reference lakes. These lakes are not considered pristine, but have little human impact and therefore are representative of the typical lakes within the ecoregion. The average range refers to the 25 th 75 th percentile range for data within each ecoregion. For the purpose of this graphical representation, the means of the reference lake data sets were used. West Leaf Lake is in the Central Hardwood Forest Ecoregion. The mean total phosphorus, chlorophyll a, and transparency (Secchi depth) for West Leaf Lake are all within the expected ecoregion ranges (Figure 13). Figure 12. Minnesota Ecoregions increased algae crystal clear 0 CHF Ecoregion West Leaf 0 CHF Ecoregion West Leaf 25 CHF Ecoregion West Leaf Figures 13a-c. West Leaf Lake ranges compared to Central Hardwood Forest Ecoregion ranges. The West Leaf Lake total phosphorus and chlorophyll a ranges are from 76 and 74, respectively, data points collected in May-September of and The West Leaf Lake Secchi depth range is from 133 data points collected in May-September from RMB Environmental Laboratories, Inc. 11 of West Leaf Lake

13 Lakeshed Data and Interpretations Lakeshed Understanding a lakeshed requires an understanding of basic hydrology. A watershed is defined as all land and water surface area that contribute excess water to a defined point. The MN DNR has delineated three basic scales of watersheds (from large to small): 1) basins, 2) major watersheds, and 3) minor watersheds. The Mississippi River-Brainerd Major Watershed is one of the watersheds that make up the Upper Mississippi River Basin, which drains south to the Gulf of Mexico (Figure 14). This major watershed is made up of 128 minor watersheds. West Leaf Lake is located in minor watershed (Figure 15). Figure 14. Pine River Watershed. Figure 15. Minor Watershed contributes water to West Lake. The MN DNR also has evaluated catchments for each individual lake with greater than 100 acres surface area. These lakesheds (catchments) are the building blocks for the larger scale watersheds. West Leaf Lake falls within lakeshed (Figure 16). Though very useful for displaying the land and water that contribute directly to a lake, lakesheds are not always true watersheds because they may not show the water flowing into a lake from upstream streams or rivers. While some lakes may have only one or two upstream lakesheds draining into them, others may be connected to a large number, reflecting a larger drainage area via stream or river networks. For further discussion and information, see page 17. The data interpretation of the West Leaf lakeshed includes only the immediate lakeshed as this area is the land surface that flows directly into West Leaf Lake. Figure 16. The West Leaf Lakeshed ( ) with land ownership, lakes, and wetlands illustrated. RMB Environmental Laboratories, Inc. 12 of West Leaf Lake

14 The lakeshed vitals table identifies where to focus organizational and management efforts for each lake (Table 9). Criteria were developed using limnological concepts to determine the effect to lake water quality. KEY Possibly detrimental to the lake Warrants attention Beneficial to the lake Table 9. West Leaf lakeshed vitals table. Lakeshed Vitals Rating Lake Area 700 acres descriptive Littoral Zone Area 292 acres descriptive Lake Max Depth 53 ft. descriptive Lake Mean Depth 22 ft. Water Residence Time NA NA Miles of Stream 1.8 descriptive Inlets 1 Outlets 1 Major Watershed 13 Redeye River descriptive Minor Watershed descriptive Lakeshed descriptive Ecoregion North Central Hardwood Forests descriptive Total Lakeshed to Lake Area Ratio (total lakeshed includes lake area) 5:1 Standard Watershed to Lake Basin Ratio (standard watershed includes lake areas) 30:1 Wetland Coverage 7.1% Aquatic Invasive Species None as of 2011 Public Drainage Ditches Public Lake Accesses 1 None Miles of Shoreline 6.9 descriptive Shoreline Development Index 1.9 Public Land to Private Land Ratio 0.009:1 Development Classification Recreational Development Miles of Road 9.7 descriptive Municipalities in lakeshed Forestry Practices None No county forest plan Feedlots 1 Sewage Management Individual waste treatment systems (last county-wide inspection in 1998) Lake Management Plan None Lake Vegetation Survey/Plan None RMB Environmental Laboratories, Inc. 13 of West Leaf Lake

15 Land Cover / Land Use The activities that occur on the land within the lakeshed can greatly impact a lake. Land use planning helps ensure the use of land resources in an organized fashion so the needs of the present and future generations can be best addressed. The purpose of land use planning is to ensure that each area of land will be used in a manner that provides maximum social benefits without degradation of the land resource. Changes in land use, and ultimately land cover, impact the hydrology of a lakeshed. Land cover is also directly related to the lands ability to absorb and store water rather than cause it to flow overland (gathering nutrients and sediment as it moves) towards the lowest point, typically the lake. Impervious intensity describes the lands inability to absorb water, the higher the % impervious intensity the more Figure 17. The West Leaf lakeshed ( ) land cover ( area that water cannot penetrate in to the soils. Monitoring the changes in land use can assist in future planning procedures to address the needs of future generations. Phosphorus export, which is the main cause of lake eutrophication, depends on the type of land cover occurring in the lakeshed. Figure 17 depicts the land cover in West leaf lakeshed. The University of Minnesota has online records of land cover statistics from years 1990 and 2000 ( Although this data is 12 years old, it is the only data available that is able to compare over a decade s time. Table 10 describes West Leaf lakeshed land cover statistics and percent change from 1990 to Due to the many factors that influence demographics, one cannot determine with certainty the projected statistics over the next 10, 20, 30+ years, but one can see the transition within the lakeshed from agriculture and grass/shrub/wetland, to forest and urban acreages. The largest change in percentage is the increase in forest cover (67%); however, in acreage. In addition, the impervious intensity has increased, which has implications for storm water runoff into the lake. The increase in impervious intensity is consistent with the increase in urban acreage. RMB Environmental Laboratories, Inc. 14 of West Leaf Lake

16 Table 10. West Leaf lakeshed land cover statistics and % change from 1990 to 2000 ( % Change Land Cover Acres Percent Acres Percent 1990 to 2000 Agriculture % Decrease Grass/Shrub/Wetland % Increase Forest % Increase Water % Decrease Urban % Increase Impervious Intensity % % Decrease % Increase % Increase % Increase % Decrease % Increase % Increase Total Area Total Impervious Area (Percent Impervious Area Excludes Water Area) % Increase Demographics West Leaf Lake is classified as a recreational development lake. These lakes usually have between 60 and 225 acres of water per mile of shoreline, 3 to 25 dwellings per mile of shoreline, and are more than 15 feet deep. The Minnesota Department of Administration Geographic and Demographic Analysis Division has extrapolated the future population of the area, in 5-year increments, out to Compared to Otter Tail County as a whole, Leaf Lake Township has a higher extrapolated growth projection (Figure 18). Figure 18. Population growth projection for Leaf Lake Township and Otter Tail County. (source: phy.state.mn.us/res ource.html?id=1933 2) RMB Environmental Laboratories, Inc. 15 of West Leaf Lake

17 West Leaf Lake Lakeshed Water Quality Protection Strategy Each lakeshed has a different combination of public and private lands. Looking in more detail at the makeup of these lands can give insight on where to focus protection efforts. The protected lands (easements, wetlands, and public land) are the future water quality infrastructure for the lake. Developed land and agriculture have the highest phosphorus runoff coefficients, so this land should be minimized for water quality protection. The majority of the land within West Leaf lakeshed is utilized for agriculture (Table 11). This land can be the focus of development and protection efforts in the lakeshed. Table 11. Land ownership, land use/land cover, estimated phosphorus loading, and ideas for protection and restoration in West Leaf Lake lakeshed (Sources: Otter Tail County parcel data, National Wetlands Inventory, and the 2006 National Land Cover Dataset). Private (79%) 20% Public (1%) Developed Agriculture Forested Uplands Other Wetlands Open Water County State Federal Land Use (%) 5.3% 51.1% 10.0% 5.5% 7.1% 20% 0.9% 0.1% 0% Runoff Coefficient Lbs of phosphorus/acre/year Estimated Phosphorus Loading Acreage x runoff coefficient <1 0 Description Focused on Shoreland Cropland Focus of development and protection efforts Open, pasture, grassland, shrubland Protected Potential Phase 3 Discussion Items Shoreline restoration Restore wetlands; CRP Forest stewardship planning, 3 rd party certification, SFIA, local woodland cooperatives Protected by Wetland Conservation Act County Tax Forfeit Lands State Forest National Forest DNR Fisheries Approach for Lake Protection and Restoration Credit: Peter Jacobson and Michael Duval, Minnesota DNR Fisheries In an effort to prioritize protection and restoration efforts of fishery lakes, the MN DNR has developed a ranking system by separating lakes into two categories, those needing protection and those needing restoration. Modeling by the DNR Fisheries Research Unit suggests that total phosphorus concentrations increase significantly over natural concentrations in lakes that have watershed with disturbance greater than 25%. Therefore, lakes with watersheds that have less than 25% disturbance need protection and lakes with more than 25% need restoration (Table 12). Watershed disturbance was defined as having urban, agricultural, and mining land uses. Watershed protection is defined as publicly owned land or conservation easement. RMB Environmental Laboratories, Inc. 16 of West Leaf Lake

18 Table 12. Suggested approaches for watershed protection and restoration of DNR-managed fish lakes in Minnesota. Watershed Watershed Management Disturbance Protected Comments Type (%) (%) < 25% > 75% Vigilance < 75% Protection 25 60% n/a Full Restoration > 60% n/a Partial Restoration Percent of the Watershed Protected Sufficiently protected -- Water quality supports healthy and diverse native fish communities. Keep public lands protected. Excellent candidates for protection -- Water quality can be maintained in a range that supports healthy and diverse native fish communities. Disturbed lands should be limited to less than 25%. Realistic chance for full restoration of water quality and improve quality of fish communities. Disturbed land percentage should be reduced and BMPs implemented. Restoration will be very expensive and probably will not achieve water quality conditions necessary to sustain healthy fish communities. Restoration opportunities must be critically evaluated to assure feasible positive outcomes. The next step was to prioritize lakes within each of these management categories. DNR Fisheries identified high value fishery lakes, such as cisco refuge lakes. Ciscos (Coregonus artedi) can be an early indicator of eutrophication in a lake because they require cold hypolimnetic temperatures and high dissolved oxygen levels. These watersheds with low disturbance and high value fishery lakes are excellent candidates for priority protection measures, especially those that are related to forestry and minimizing the effects of landscape disturbance. Forest stewardship planning, harvest coordination to reduce hydrology impacts, and forest conservation easements are some potential tools that can protect these high value resources for the long term. West Leaf lakeshed is classified with having 27.2% of the watershed protected and 59.1% of the watershed disturbed (Figure 19), indicating it should have a full restoration focus. Goals for the lake should limit any increase in disturbed land use and implement best management practices. Figure 20 displays the upstream lakesheds that contribute water to the lakeshed of interest. All of the land and water area in this figure has the potential to contribute water to West Leaf Lake, whether through direct overland flow or through a creek or river. Six of the 9 upstream lakesheds have the same management focus (full restoration). 0% 75% 100% West Leaf Lake (27.2%) Percent of the Watershed with Disturbed Land Cover 0% 25% 100% West Leaf Lake (59.1%) Figure 19. West Leaf lakeshed s percentage of watershed protected and disturbed. Figure 20. Upstream lakesheds that contribute water to the West Leaf lakeshed. Color-coded based on management focus (Table 12). RMB Environmental Laboratories, Inc. 17 of West Leaf Lake

19 West Leaf Lake, Status of the Fishery (as of 07/19/2010) West Leaf Lake is a 684-acre mesotrophic (moderately fertile) lake located in east central Otter Tail County approximately two miles east of Ottertail, MN. West Leaf Lake is connected to Middle Leaf Lake via an non-navigable culvert along the east shoreline. The immediate watershed is composed primarily of agricultural land interspersed with hardwood woodlots and marshland. West Leaf Lake has a maximum depth of 55 feet; however, 37% of the lake is less than 15 feet in depth. The Secchi disk reading during the 2010 lake survey was 8.5 feet; readings have ranged from 5.6 to 9.9 feet. Development is located around the entire shoreline of West Leaf Lake. The 1994 lake resurvey report referenced 129 homes and cabins along the shoreline, with one resort located along the northeast shoreline. A state-owned concrete public access is located on a township road along the northeast shoreline off of County Highway 108. Shoal water substrates consist primarily of sand and gravel. There are extensive areas of emergent aquatic plants (harstem bulrush, wild rice, and common cattail) present in the lake. Plants such as these provide valuable fish and wildlife habitat, and are critical for maintaining good water quality. They protect shorelines and lake bottoms, absorbing and breaking down pollution. Emergent plants also provide spawning areas for fish such as northern pike, largemouth bass, and panfish, and serve as important nursery areas for all species of fish. Due to their ecological value, emergent plants may not be removed without a DNR permit. To maintain the excellent water quality and angling, it is imperative to preserve quality aquatic habitat. West Leaf Lake can be ecologically classified as a bass-panfish-walleye type of lake and this is reflected in the assemblage of the fish community. Walleye, northern pike, largemouth bass, and bluegill are the dominant game species in the fish community. The prolificacy of these species can be attributed to the abundance of suitable spawning habitat. Walleye abundance has historically fluctuated. In this survey, the test-net catch rate was within the expected range for this type of lake. Walleyes ranged in length from 9.2 to 23.0 inches with an average length and weight of 15.7 inches and 1.5 pounds. Individuals attained an average length of 16.4 inches at four years of age. Historically, the northern pike population has remained abundant. Age data from recent surveys indicate that northern pike exhibit consistently good reproduction. Pike ranged in length from 9.2 to 26.4 inches with an average length and weight of 18.5 inches and 1.4 pounds. Growth rates are slow with an average length of 22.1 inches at six years of age. This may correspond with a low abundance of yellow perch, a preferred forage fish. Test-net catch data indicate that largemouth bass are also abundant. Age data indicate that largemouth bass reproduction is consistently good. Individuals ranged in length from 4.2 to 15.6 inches, with an average length of 11.8 inches at four years of age. Historically, the bluegill population has exhibited large fluctuations in abundance. The test-net catch rate for this survey was within the expected range. Fifteen percent of those caught were 7.0 inches or greater in length. Average lengths of 7.3 inches were present at eight years of age. Anglers can maintain or improve the quality of angling by practicing selective harvest. This management practice encourages the release of medium to large size fish while allowing the harvest of more abundant, smaller fish for table fare. Releasing the medium to large fish will ensure that the lake has enough spawning-age fish annually, providing anglers with more opportunities to catch large fish in the future. See the link below for specific information on gillnet surveys, stocking information, and fish consumption guidelines. RMB Environmental Laboratories, Inc. 18 of West Leaf Lake

20 Key Findings / Recommendations Monitoring Recommendations Transparency monitoring at site 202 should be continued annually. It is important to continue monitoring weekly, or at least bimonthly, every year to enable annual comparisons and trend analyses. In order to track future water quality trends, phosphorus and chlorophyll a monitoring should continue as the budget allows. Overall conclusions West Leaf Lake is currently in good shape regarding water quality, however, the lakeshed needs restoration from disturbed land uses. West Leaf Lake is a mesotrophic lake (TSI=47) with no significant trends in water quality. One percent (1%) of the lakeshed is in public ownership, and 27% of the lakeshed is protected, while 59% is disturbed (Figure 19). West Leaf Lake is in an interesting position hydrologically, falling along the western edge of the Upper Mississippi River Basin; a few miles west is the Red River Basin containing Otter Tail Lake. West Leaf Lake has a moderately small watershed (Figure 20) primarily composed of agricultural land. A surface water runoff analysis, on the following pages, shows the majority of runoff into the lake occurs from the surrounding shoreline and nearby agriculture. The areas in red show the highest priority runoff areas. These areas can be targeted for wetland restoration, shoreline restoration, and rain garden projects. Priority Impacts to the lake Agricultural land use in the lakeshed is high (51%), and is the reason for the lakeshed being classified as full restoration (Table 12, Figure 20). Shoreline buffers are thin in many farmed sections (especially the northeast side), so nutrient and sediment runoff from agricultural lands into the lake and stream inlets may affect water quality. Agricultural uses include pasture/hay, cultivated crops, and animal feedlots. Although the first tier around the lake is mostly developed, new development pressure does not appear to be very high. From , there was a negligible increase in urban and impervious acreages (Table 10). In the future, if the second tier becomes developed, it could significantly impact the drainage around the lake. West Leaf Lake has extensive areas of emergent aquatic plants in the lake. If these plants are removed, they could greatly impact the fish and wildlife habitat and the water quality of the lake. See the best management practices section for more explanation on protecting these areas. Best Management Practices Recommendations The management focus for West Leaf Lake should protect the current water quality, and restore and protect more of the lakeshed. Partnering with farmers to implement conservation farming practices, increase lake and stream shoreline buffers, and place priority parcels into land retirement programs can decrease the impacts of agriculture in the lakeshed. Protection efforts should be also focused on managing and/or decreasing the impact caused by additional development, including second tier development, and impervious surface area. Project ideas include protecting land with conservation easements, enforcing county shoreline ordinances, smart development, shoreline restoration, rain gardens, and septic system maintenance There are extensive areas of emergent aquatic plants (harstem bulrush, wild rice, and common cattail) present in the lake. Plants such as these provide valuable fish and wildlife habitat, and are RMB Environmental Laboratories, Inc. 19 of West Leaf Lake

21 critical for maintaining good water quality. They protect shorelines and lake bottoms, absorbing and breaking down pollutants. Emergent plants provide spawning areas for fish such as northern pike, largemouth bass, and panfish, and serve as important nursery areas for all species of fish. Due to their ecological value, emergent plants may not be removed without a DNR permit. To maintain the excellent water quality and angling, it is imperative to preserve quality aquatic habitat. Project Implementation The best management practices above can be implemented by a variety of entities. Some possibilities are listed below. Individual property owners Shoreline restoration Rain gardens Aquatic plant bed protection (only remove a small area for swimming) Lake Associations Lake condition monitoring Internal loading monitoring Ground truthing visual inspection upstream on stream inlets Watershed mapping by a consultant Shoreline inventory study by a consultant Soil and Water Conservation District (SWCD) and Natural Resources Conservation Service (NRCS) Shoreline restoration Stream buffers Work with farmers to o Restore wetlands o Implement conservation farming practices o Participate in land retirement programs such as Conservation Reserve Program Organizational Contacts and Reference Sites Leaf Lakes Area Association DNR Fisheries Office Regional Minnesota Pollution Control Agency Office Otter Tail Soil and Water Conservation District st Avenue North, Fergus Falls, MN fergusfalls.fisheries@state.mn.us Lake Ave., Suite 220, Detroit Lakes, MN , Jenny Ave SW Suite 2, Perham, MN ext.3 RMB Environmental Laboratories, Inc. 20 of West Leaf Lake

22 West Leaf Lake Watershed Analysis for Non-Point Water Quality Projects This project used computer analysis of new LiDAR elevation data to determine which areas of the watershed have the potential to deliver nutrients to West Leaf Lake by surface water runoff. This analysis does not account for how the land is currently being used but instead highlights areas where pollution reducing practices will have a direct benefit to the lake. Prepared By: Steve Henry Otter Tail County Shoreland Specialist

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