Clearwater Lake CLEARWATER / BELTRAMI COUNTY

Transcription

1 Clearwater Lake CLEARWATER / BELTRAMI COUNTY Lake Water Quality Summary Clearwater Lake is located on the border of Clearwater and Beltrami Counties, 16.5 miles northeast of the city of Bagley. It has an oblong shape that covers acres (Table 1). Clearwater Lake has two inlets and one outlet, which classifies it as a drainage lake (Figure 1). The Clearwater River flows into the lake along the southern shore and flows out through the large bay along the northwest shore. There is a small intermittent creek that flows into the lake on the north shore. At the outlet of the lake, the Clearwater River takes a northwest path through low marshland as it forms the southwest border of the Red Lake Indian Reservation; eventually joining up with the Red Lake River near the city of Red Lake Falls. Water quality data have been collected on Clearwater Lake in (Tables 2-3). These data show that the lake is mesotrophic, which is characteristic of moderately clear water throughout the summer and excellent recreational opportunities (page 9). The Clearwater Lake Association was organized in Their mission statement is to improve and maintain the environment and quality of life through education, awareness and responsibility of our community for ours and future generations. The association has been involved in many activities including water quality monitoring and publishing a newsletter. The most recent lake management plan was completed in Table 1. Clearwater Lake location and key physical characteristics. Location Data MN Lake ID: County: Beltrami Ecoregion: Northern Lakes and Forests Major Drainage Basin: Red River Latitude/Longitude: / Invasive Species: None as of 2011 Table 2. Availability of primary data types for Clearwater Lake. Data Availability Physical Characteristics Surface area (acres): 1,008 Littoral area (acres): 339 % Littoral area: 33% Max depth (ft), (m): 65, 19.8 Inlets: 2 Outlets: 1 Public Accesses: 1 Transparency data Excellent CLMP data source from Chemical data Good data source covering 1992, 1993, , 2005, 2006 and Inlet/Outlet data Good data source covering Recommendations For recommendations refer to page 20. RMB Environmental Laboratories, Inc. 1 of Clearwater Lake

2 Lake Map Figure 1. Map of Clearwater 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. Lake Site Depth Monitoring Programs (ft) MPCA: MPCA: CLMP: CLMP: 1994, CLMP: , MPCA: *Primary site 45 CLMP: ; Red Lake Watershed CWP: 1992, 1993, 2002, 2003, 2005, CLMP: 1996, 1998; Lake Association: 2010 Acronyms Minnesota Pollution Control Agency (MPCA) Citizen Lake Monitoring Program (CLMP) Clean Water Partnership (CWP) RMB Environmental Laboratories, Inc. 2 of Clearwater Lake

3 Average Water Quality Statistics Table 4 describes available chemical data for the primary site (204) of Clearwater Lake through 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. Though Clearwater Lake is located within the Northern Lakes and Forest category, it is unique because 4 different ecoregion boundaries are within 12 miles of Clearwater Lake. 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 Waters Standard 2 Ecoregion Parameter Mean Range 1 Interpretation Total phosphorus (ug/l) > 30 Results are within the expected 3 Chlorophyll a (ug/l) > 9 Chlorophyll a max (ug/l) 21 < 15 Secchi depth (ft) Dissolved oxygen Dimictic See page 8 ( ) < 6.6 range for the ecoregion, except for the max chlorophyll a. Dissolved oxygen depth profiles show that the deep areas of the lake are anoxic in late summer. Total Kieldahl Nitrogen Indicates insufficient nitrogen to support summer nitrogen-induced (mg/l) 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 Within the expected range for the ecoregion. Lake water ph less than 6.5 can affect fish spawning and the solubility of metals in the water. Chloride (mg/l) NA No data available. Total Suspended Solids (mg/l) 2 < 1 2 Indicates low suspended solids and clear water. Conductivity (umhos/cm) Above the expected range; however the bordering ecoregion (CHF) range is Total Nitrogen :Total Phosphorus 25:1 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 Clearwater Lake

4 Water Quality Characteristics - Historical Means and Ranges Table 5. Water quality means and ranges for primary sites. Years monitored for chemical data: 1992, 1993, , 2005, 2006, Years monitored for secchi data: 1992, 1993, Primary Parameters Site 204 Total Phosphorus Mean (ug/l): 24 Total Phosphorus Min: 3 Total Phosphorus Max: 51 Number of Observations: 78 Chlorophyll a Mean (ug/l): 7 Chlorophyll-a Min: <1 Chlorophyll-a Max: 21 Number of Observations: 59 Secchi Depth Mean (ft): 9.7 Secchi Depth Min: 3.0 Secchi Depth Max: 21.5 Number of Observations: 282 Figure 2. Clearwater Lake total phosphorus, chlorophyll a and transparency historical ranges. The arrow represents the range and the black dot represents the historical mean (Primary Site 204). Figure Clearwaterpted after Moore and Thornton, [Ed.] Lake and Reservoir Restoration Guidance Manual. (Doc. No. EPA 440/ ) RMB Environmental Laboratories, Inc. 4 of Clearwater Lake

5 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 only grow in areas of lakes where the sunlight 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. At site 204, the mean transparency ranges from 8.3 to 12.1 feet (Figure 3). The transparency was above the long-term mean during 1996, 2000, 2001, 2003, 2004 and Transparency monitoring should be continued annually at sites 204 in order to track water quality changes. 14 Transparency: Annual Means 12 Secchi Depth (ft) Site 204 Long term mean 0 Figure 3. Annual mean transparency compared to long-term mean transparency, site 204. Clearwater Lake individual data transparency points range from 3.0 to 21.5 ft at the primary site (204). Figure 4 shows the seasonal transparency dynamics. Transparency is lower in April and early May as the lake is turning over. The maximum Secchi reading is usually obtained in early summer. The transparency then declines in late July and August, and increases again in early October after fall turnover. This transparency dynamic is typical of a northern Minnesota lake. The dynamics have to do with algae 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 Clearwater Lake

6 Secchi Depth (ft) Seasonal Transparency Dynamics Figure 4. Seasonal transparency dynamics and year to year comparison (Primary Site 204). The gray line represents the average from User Perceptions When volunteers collect secchi depth readings, they record their perceptions 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 decreases. Clearwater Lake was rated as being "crystal clear" 23% of the time between (Figure 5). 2% Physical Appearance Rating 23% 23% 23% Crystal clear water 52% Not quite crystal clear a little algae visible 23% Definite algae green, yellow, or brown color apparent 2% High algae levels with limited clarity and/or mild odor apparent 52% 0% Severely high algae levels Figure 5. Physical appearance rating, as rated by the volunteer monitor ( ). RMB Environmental Laboratories, Inc. 6 of Clearwater Lake

7 As the secchi depth decreases, the perception of recreational suitability of the lake decreases. Clearwater Lake was rated as being "beautiful" 34% of the time from (Figure 6). 5% Recreational Suitability Rating 24% 34% 34% Beautiful, could not be better 37% Very minor aesthetic problems; excellent for swimming, boating 24% Swimming and aesthetic enjoyment of the lake slightly impaired because of algae levels 37% 5% Desire to swim and level of enjoyment of the lake substantially reduced because of algae levels 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 ( ). Total Phosphorus Clearwater Lake is phosphorus limited, which means that algae and aquatic plant growth is dependent upon available phosphorus. Total phosphorus was evaluated in Clearwater Lake in 1992, 1993, , 2005, 2006 and The data do not indicate a seasonal pattern (Figure 7); though the variability across years and within each individual year is high. The data does not appear to be clustered into specific ranges. The majority of the data points fall in the upper mesotrophic category. Phosphorus should continue to be monitored to track any future changes in water quality. Total Phosphorus (ug/l) Eutrophic Mesotrophic Oligotrophic Total Phosphorus Figure 7. Historical total phosphorus concentrations (ug/l) for Clearwater Lake, site 204 (data sets from , 2005, 2006, ). RMB Environmental Laboratories, Inc. 7 of Clearwater Lake

8 Chlorophyll a Chlorophyll a is the pigment that makes plants and algae green. Chlorophyll a 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 Clearwater Lake in 1993, , 2005, 2006, Figure 8 indicates that minor algae blooms occur most years, and nuisance algae blooms have occurred on occasion. The algae blooms in early October could be due to fall turnover. Chlorophyll a ug/l Chlorophyll a Minor Algae Nuisance Algae Figure 8. Chlorophyll a concentrations (ug/l) for Clearwater Lake (data from , 2005, 2006, ). 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. Clearwater Lake is a relatively deep lake, with a maximum depth of 60 ft. Dissolved oxygen profiles from 1996 indicate that site 101 stratifies in the summer. The thermocline in June was around 6 meters (20 feet). Benthic phosphorus samples taken in 1996 at site 101 indicate internal loading (range from ug/l). Figure 9 illustrates the stratification process throughout the 1996 season at site 101. This is a representative DO profile for Clearwater Lake. Figure 9. Dissolved oxygen profile for Clearwater Lake in 1996 at site 101. RMB Environmental Laboratories, Inc. 8 of Clearwater Lake

9 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 to each other 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 204. Trophic State Index Site 204 TSI Total Phosphorus 48 TSI Chlorophyll-a 47 TSI Secchi 45 TSI Mean 46 Trophic State: Mesotrophic Numbers represent the mean TSI for each parameter. Hypereutrophic 100 The mean TSI for the two main sites of Clearwater Lake fall into the mesotrophic category (40-50) (Figure 10). There is good agreement between the TSI for phosphorus, chlorophyll a and transparency, indicating that these variables are strongly related Clearwater Lake (Table 6). Eutrophic Mesotrophic Mesotrophic lakes (TSI 40-50) are characterized by moderately clear water most of the summer (Table 7). "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. 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 Clearwater Lake

10 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 wet years and dry years, water levels, weather, etc, that affect the water quality naturally. There is enough historical data to perform trend analysis for total phosphorus, chlorophyll a and transparency on Clearwater Lake. Site 204 has over 8 years of transparency data, which was enough data to perform a long-term trend analysis (Figure 11). The data was analyzed using the Mann Kendall Trend Analysis Clearwater Transparency Trend (site 204) 20.0 Secchi depth (ft) Figure 11. Transparency(ft) trend for site 204 from No consistent significant trend was detected for site 204 on Clearwater Lake for total phosphorus, chlorophyll a or transparency (Table 8). Transparency monitoring should continue because though there was not a significant trend looking at all the secchi data, there was a decreasing trend (90%) when looking at only the secchi maximums between years. Table 8. Trend analysis results for site 204. Lake Site Parameter Date Range Trend Probability Site 204 Total Phosphorus , 2005, 2006, No Trend -- Site 204 Chlorophyll a , 2005, 2006, No Trend -- Site 204 Transparency No Trend -- RMB Environmental Laboratories, Inc. 10 of Clearwater Lake

11 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 reference lakes are not considered pristine, but are considered to 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. Clearwater Lake is in the Northern Lakes and Forests Ecoregion. The mean total phosphorus, chlorophyll a and transparency (secchi depth) for Clearwater are all within the expected ecoregion ranges (Figure 13). Figure 12. Map of Minnesota with the seven ecoregions Total Phosphorus (ug/l, ppb) Chlorophyll-a (ug/l, ppb) Secchi depth (ft) increased algae crystal clear 0 NLF Ecoregion Clearwater 0 NLF Ecoregion Clearwater 25 NLF Ecoregion Clearwater Figures 13a-c. Clearwater Lake ranges compared to Northern Lakes and Forest Ecoregion ranges. The Clearwater Lake total phosphorus and chlorophyll a ranges are from 24 data points collected in May-September of 1986, 1999, 2000, The Clearwater Lake Secchi depth range is from 288 data points collected in May-September from RMB Environmental Laboratories, Inc. 11 of Clearwater Lake

12 Inlet/Outlet Assessment Clearwater Lake has one major inlet and one outlet (Figure 14). The inlet (Clearwater River, S ) and outlet (Clearwater River, S ) have been monitored in the 1980s through the 2000s. When compared to the ecoregion ranges for streams, the data fit very well (Table 9). The results for the outlet are similar to the inlake concentration, which is typical because the outlet water is coming directly from the lake. (Figure 15). The total phosphorus concentration, total suspended solids, and turbidity at the inlet is slighly higher than the ecoregion range (Table 9). This could be due to disturbance in the watershed (see page 18). Clearwater Lake is at the end of the very large Clearwater River Watershed. In , the mean phosphorus concentration at the inlet was much higher than other years (Figure 15), but this was due to one high phosphorus result at the end of March in each of 2003 and Precipitation records do not show above average rainfall during that time, so there may be some other impacting factor that occurred. For a more in-depth assessment of the Clearwater River upstream from Clearwater Lake, please refer to the Clearwater Lake Management Plan: Figure 14. Map of Clearwater Lake and its inlets and outlets. Total Phosphorus (ug/l) Inlet In Lake Outlet Total Phosphorus Figure 15. Total Phosphorus annual means for the inlet, outlet and lake. Table 9. Monitoring results ( means) for the Clearwater Lake inlet and outlet compared to the ecoregion range. Site Description N+N (mg/l) TP (ug/l) OP (ug/l) TSS (mg/l) Turbidity (NTU) Field ph Inlet (S ) Outlet (S ) Ecoregion Range NA RMB Environmental Laboratories, Inc. 12 of Clearwater 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 Clearwater River Major Watershed is one of the watersheds that make up the Red River Basin, which drains north to Lake Winnipeg (Figure 16). This major watershed is made up of 88 minor watersheds. Clearwater Lake is located in minor watershed (Figure 17). Figure 16. Clearwater River Watershed. 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. Clearwater Lake falls within the Clearwater ( ) lakeshed (Figure 18). 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 of lakesheds, reflecting a larger drainage area via stream or river networks. For further discussion of Clearwater Lake s full watershed, containing all the lakesheds upstream of Clearwater Lake lakeshed, see page 18. The data interpretation of the Clearwater Lake lakeshed includes only the immediate lakeshed, not including the upstream lakesheds, as this area is the land surface that flows directly into Clearwater Lake. Figure 17. Minor Watershed contributes water to Clearwater Lake. Figure 18. Clearwater ( ) lakeshed with land ownership, lakes, wetlands, and rivers illustrated. RMB Environmental Laboratories, Inc. 13 of Clearwater Lake

14 The lakeshed vitals table (Table 10) identifies where to focus organizational and management efforts for each lake. 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 10. Clearwater Lake lakeshed vitals table. Lakeshed Vitals Rating Lake Area acres descriptive Littoral Zone Area acres descriptive Lake Max Depth 60 ft. descriptive Lake Mean Depth 27.2 ft. Water Residence Time NA NA Miles of Stream 40.5 descriptive Inlets 2 Clearwater River Outlets 1 Clearwater River Major Watershed 66 Clearwater River descriptive Minor Watershed descriptive Lakeshed descriptive Ecoregion Northern Lakes and Forest descriptive Total Lakeshed to Lake Area Ratio (total lakeshed includes lake area) 16:1 Standard Watershed to Lake Basin Ratio (standard watershed includes lake areas) 109:1 Wetland Coverage 9.5% Aquatic Invasive Species None Public Drainage Ditches None Public Lake Accesses 1 Miles of Shoreline 8.9 descriptive Shoreline Development Index 2.0 Public Land to Private Land Ratio 0.7:1 Development Classification Recreational Development Miles of Road 40.7 Municipalities in lakeshed None Forestry Practices Resource Management Plan July 2008 Feedlots 3 Sewage Management Land use permits require septic systems to be up to state code; septic system compliance inventory completed in 1999 Lake Management Plan Minnesota Board of Water and Soil Resources Challenge Grant, 2003 Lake Vegetation Survey/Plan None RMB Environmental Laboratories, Inc. 14 of Clearwater 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 that the needs of the present and future generations can be best addressed. The basic 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 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 19 depicts the land cover in Clearwater Lake s lakeshed. The University of Minnesota has online records of land cover statistics from years 1990 and 2000 ( Although this data is 11 years old, it is the only data set available to compare over a decade of time. Table 11 describes Clearwater Lake s 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 Figure 19. Clearwater ( ) Lakeshed land cover ( one can see the transition within the lakeshed from agriculture, grass/shrub/wetland, and water acreages to forest and urban acreages. In this particular lakeshed, land use has not changed significantly during the decade from There was about a 1,000 acre decrease in agriculture. The grass/shrub/wetland category decreased with a similar percent increase in forest cover. These are relatively minor changes in land use during this decade. RMB Environmental Laboratories, Inc. 15 of Clearwater Lake

16 Table 11. Clearwater Lake s lakeshed land cover statistics and % change from 1990 to 2000 ( % Change Land Cover Acres Percent Acres Percent 1990 to 2000 Agriculture 4, , % decrease Forest 9, , % increase Grass/Shrub/Wetland 1, , % decrease Water 1, % decrease Urban % increase Impervious Intensity % 0 16, , The impervious surface data did not have a high enough resolution to capture any changes from The increase in urban acreage can be used as a surrogate for the increase in impervious Total Area 16,316 16,316 intensity. Total Impervious Area (Percent Impervious Area Excludes Water Area) Demographics Clearwater Lake is classified as a recreational development lake. Recreational development lakes usually have between 60 and 225 acres of water per mile of shoreline, between 3 and 25 dwellings per mile of shoreline, and are more than 15 feet deep. The Minnesota Department of Administration Geographic and Demographic Analysis Division extrapolated future population in 5- year increments out to These projections are shown in Figure 20 below. Compared to Clearwater County as a whole, Sinclair Township has a lower extrapolated growth projection. However Beltrami County as a whole, Roosevelt Township has a higher extrapolated growth projection. Figure 20. Population growth projection for Sinclair Township and Clearwater County and Roosevelt Township and Beltrami County. (source: ate.mn.us/resource.html?i d=19332) RMB Environmental Laboratories, Inc. 16 of Clearwater Lake

17 Clearwater Lake Lakeshed Water Quality Protection Strategy Each lakeshed has a different makeup 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, 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 Clearwater Lake s lakeshed is made up of private forested uplands (Table 12). This land can be the focus of development and protection efforts in the lakeshed. In addition, 1.7% of the public land in the lakeshed is in a perpetual easement protecting trout habitat in Clearwater River. Table 12. Land ownership, land use/land cover, estimated phosphorus loading, and ideas for protection and restoration in Clearwater lakeshed (Sources: Minnesota DNR GAP Stewardship data, National Wetlands Inventory, and the 2006 National Land Cover Dataset). Developed Agriculture Private (56%) 6% Public (38%) Forested Uplands Other Wetlands Open Water County State Federal Land Use (%) 2.1% 14.5% 28.9% 4.6% 5.9% 6% 37.5% 0.4% 0.09% Runoff Coefficient Lbs of phosphorus/acre/ year Estimated Phosphorus Loading Acerage x runoff coefficient 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% disturbance need restoration (Table 13). 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. 17 of Clearwater Lake

18 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. Table 13. Suggested approaches for watershed protection and restoration of DNR-managed fish lakes in Minnesota. Watershed Disturbance (%) Watershed Protected (%) Management Type Comments > 75% Vigilance < 25% < 75% Protection 25-60% n/a Full Restoration > 60% n/a Partial Restoration 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 Clearwater lakeshed is classified having 44.9% of the watershed protected and 18.3% of the watershed disturbed (Figure 21). Therefore, Clearwater Lake should have a protection focus. The goals for the lake should be to limit any increase in disturbed land use. Figure 22 displays the upstream lakesheds that contribute water the lakeshed of interest. All of the land and water area in this figure has the potential to contribute water to Clearwater Lake, whether through direct overland flow or through a creek or river. Ten of the 15 upstream lakesheds are more disturbed than the Clearwater lakeshed and should have a restoration focus. Percent of the Watershed Protected 0% 75% 100% Clearwater Lake (44.9%) Percent of the Watershed with Disturbed Land Cover 0% 25% 100% Clearwater Lake (18.3%) Figure 21. Clearwater lakeshed s percentage of watershed protected and disturbed. Figure 22. Upstream lakesheds that contribute water to the Clearwater lakeshed. Color-coded based on management focus (Table 13). RMB Environmental Laboratories, Inc. 18 of Clearwater Lake

19 Status of the Fishery (as of 08/06/2007) Clearwater Lake is on the border of Beltrami and Clearwater Counties northeast of the city of Leonard. The 1008-acre lake has a maximum depth of 65 feet and a 54,000-acre watershed. There is a DNR public access on the northwest corner of the lake off of county road 4. The Minnesota Department of Natural Resources has classified Minnesota's lakes into 43 different lake classes based on physical and chemical characteristics. Clearwater Lake is in lake class 27. Lakes in this lake class are typically large, deep, and have regular-shaped shorelines. Clearwater Lake is managed for walleye, northern pike, sunfish, black crappie and largemouth bass. Fishermen have a wide variety of fish to angle for. Because of its riverine characteristic, some species more commonly found in a river environment are also found in Clearwater Lake such as the redhorse sucker species. Clearwater Lake has a very good walleye fishery that is maintained by a combination of natural reproduction and fingerling stocking. Walleye abundance in 2007 of 10 fish per gill net set is typical of past assessments. Walleye sampled ranged in length from 9 to 30 inches with the majority of walleye in the inch size. Eight different year-classes were identified in 2007 with the 2004 and 2005 year-classes making up 83% of the sample. Northern pike abundance has been relatively consistent over all previous assessments dating back to 1953, generally ranging from 5-10 per gill net. Clearwater Lake has a reputation for producing large pike and the average weight in 2007 of 3.1 pounds is the largest of all the assessments. Pike ranged from 13 to 34 inches with most in the inch size range. Pike have a diverse forage supply for good growth rates including a variety of redhorse species, white sucker, tullibee, and yellow perch. This lake also has the physical characteristics such as large size and deep cool water refuge to produce large pike exceeding 20 pounds. There are no protected size limits in place but anglers can help by voluntary release of mid-sized pike in the inch sizes so that more fish can attain their ultimate size potential. There are many members of the sunfish family available for anglers to enjoy including bluegill, pumpkinseed, rock bass, largemouth bass, and black crappie. Bluegill abundance appears to be increasing and fish up to nine inches were sampled, however, quality (the proportion of larger fish in the population) in recent years has declined. This may be an indication of angler harvest on the select preferred sizes. Most of the shoreline around Clearwater Lake is privately owned and subject to development. Development pressure is increasing around the shorelines and within the watersheds on Minnesota lakes. This degrades water quality and impacts valuable shoreline habitat. Native shoreline vegetation provides habitat for fish and wildlife, filters harmful nutrients, and protects against shoreline erosion. Lakeshore owners can minimize their impact on the shoreline and maintain a more natural setting while actually decreasing annual maintenance. For more information on how to accomplish this, contact your nearest Area Fisheries office or go to the following website: See the link below for specific information on gillnet surveys, stocking information, and fish consumption guidelines. RMB Environmental Laboratories, Inc. 19 of Clearwater Lake

20 Key Findings / Recommendations Monitoring Recommendations Transparency monitoring at site 204 should be continued annually. It is important to continue transparency monitoring weekly or at least bimonthly every year to enable year-to-year comparisons and trend analyses. Phosphorus monitoring in the lake and at the inlet will show the effectiveness of upstream projects in the watershed. Priority Impacts to the lake Clearwater Lake has a very large catchment and watershed (109:1 watershed to lake area ratio). Immediate catchment and watershed is well protected by public land and a perpetual easement protecting trout habitat in the Clearwater River (Figure 21). Further upstream, the watershed is more disturbed. Agricultural acreage increases along the Clearwater River towards Bagley. Best Management Practices Recommendations Projects that would have the best chance of improving the water quality of Clearwater Lake include runoff and sedimentation reduction in the Bagley area, and buffer strips along the whole Clearwater River, especially in the area downstream of Bagley. General Recommendations There is no evidence of a declining water quality trend in Clearwater Lake. The Red Lake Watershed District has implemented many projects along the Clearwater River and in Bagley to improve the water quality. Continued monitoring will show the effectiveness of these projects in maintaining and improving water quality in the Clearwater River and in Clearwater Lake. Organizational contacts and reference sites Clearwater Lake Association DNR Fisheries Office Regional Minnesota Pollution Control Agency Office Clearwater Soil and Water Conservation District Red Lake Watershed District PO Box 803, Thief River Falls, MN coreyh@wiktel.com Lake Management Plan: Bemidji Avenue, Bemidji, MN bemidji.fisheries@state.mn.us Lake Ave., Suite 220, Detroit Lakes, MN , Main Avenue North, Suite 3, Bagley, Minnesota RMB Environmental Laboratories, Inc. 20 of Clearwater Lake