Balsam Lake ITASCA COUNTY

Transcription

1 Balsam Lake ITASCA COUNTY Lake Water Quality Summary Balsam Lake is located 27 miles north of Grand Rapids, MN in Itasca County. It has many bays and covers 714 acres total (Table 1). Balsam Lake has five inlets and one outlet, which classify it as a drainage lake. Water enters Balsam Lake from nearby lakes. Balsam Creek exits the lake to the east and carries water to the Prairie River, which eventually drains into the Mississippi River. Water quality data have been collected on Balsam Lake from (Tables 2 & 3). These data show that the lake is mesotrophic (TSI = 44) with clear water conditions most of the summer and excellent recreational opportunities. Table 1. Balsam Lake location and key physical characteristics. Location Data MN Lake ID: County: Itasca Ecoregion: Northern Lakes and Forests Major Drainage Basin: Mississippi R. Grand Rapids Latitude/Longitude: / Invasive Species: Curly-Leaf Pondweed Physical Characteristics Surface area (acres): 714. Littoral area (acres): 299. % Littoral area: 42. Max depth (ft), (m): 37.5, 11.4 Inlets: 5 Outlets: 1 Public Accesses: 1 Table 2. Availability of primary data types for Balsam Lake. Data Availability Transparency data Good data source from Chemical data Most recent data from Inlet/Outlet data Site S6-111 (Figure 1) is monitored for transparency by a volunteer. More data would be helpful in determining any potential impacts to the lake. Recommendations For recommendations refer to page 18. RMB Environmental Laboratories, Inc. 1 of Balsam Lake

2 Lake Map Figure 1. Map of Balsam Lake with 21 aerial imagery and illustrations of lake depth contour lines, sample site locations, inlets and outlets, and public access points. Table 3. Monitoring programs and associated monitoring sites. Monitoring programs include the Citizen Lake Monitoring Program (CLMP), Itasca County Lake Assessment (ICLA), Itasca County Lakes Inventory (ICL), Minnesota Pollution Control Agency (MPCA). Lake Site Depth (ft) Monitoring Programs 1 NA ICLA: 1994, 21-22; MPCA: CLMP: 1986, ICLA: *Primary site 37 ICLA: 1993; ICL: ICLA: 1993 RMB Environmental Laboratories, Inc. 2 of Balsam Lake

3 Water Quality Characteristics - Historical Means and Ranges Table 4. Water quality means and ranges for primary sites. Parameters Primary Site 21 Site 23 Total Phosphorus Mean (ug/l): Total Phosphorus Min: Total Phosphorus Max: Number of Observations: 6 14 Chlorophyll a Mean (ug/l): Chlorophyll-a Min: Chlorophyll-a Max: Number of Observations: 3 1 Secchi Depth Mean (ft): Secchi Depth Min: Secchi Depth Max: Number of Observations: Figure Figure 2. Balsam 2. Lake Lake insert total total phosphorus, phosphorus, chlorophyll chlorophyll a and a and transparency transparency historical historical ranges. ranges. The The arrow arrow represents represents the the range range and and the the black black dot dot represents represents the the historical historical mean mean (Primary (Primary Site Site 21). xxx). Figure Figure adapted adapted after Moore and Thornton, [Ed.] Lake and Reservoir Restoration Guidance Manual. (Doc. No. EPA 44/5-88-2) after Moore and Thornton, [Ed.] Lake and Reservoir Restoration Guidance Manual. (Doc. No. EPA 44/5-88-2) RMB Environmental Laboratories, Inc. 3 of Balsam Lake

4 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 in Balsam Lake ranges from 8.5 to 12.4 feet (Figure 3). The annual means hover fairly close to the long-term mean. For trend analysis, see page 1. Transparency monitoring should be continued annually in order to track water quality changes. 14 Transparency and Precipitation 1 Secchi Depth (ft) Precipitation secchi Mean Precipitation (in) Figure 3. Annual mean transparency compared to long-term mean transparency, site 21. Date Balsam Lake transparency ranges from 6.5 to 15.5 feet at site 21. Figure 4 shows the seasonal transparency dynamics. The maximum Secchi reading is usually obtained in early summer. Balsam Lake transparency is high in June, and then declines through August. This transparency dynamic is typical of a Minnesota lake. The dynamics have to do with 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. 4 of Balsam Lake

5 Secchi Depth (ft) Seasonal Transparency Dynamics Grand Total Figure 4. Seasonal transparency dynamics and year to year comparison (Site 21). The black line represents the pattern in the data. 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. Balsam Lake was rated as being "not quite crystal clear" 86% of the time by samplers at site 21 between 1992 and 213 (Figure 5). 14% Physical Appearance Rating % Crystal clear water 86% Not quite crystal clear a little algae visible 14% Definite algae green, yellow, or brown color apparent % High algae levels with limited clarity and/or mild odor apparent 86% % Severely high algae levels Figure 5. Balsam Lake physical appearance ratings by samplers. RMB Environmental Laboratories, Inc. 5 of Balsam Lake

6 As the Secchi depth decreases, the perception of recreational suitability of the lake decreases. Balsam Lake was rated as having "very minor aesthetic problems" 99% of the time from 1992 to 213 (Figure 6). Recreational Suitability Rating 1% % Beautiful, could not be better 99% Very minor aesthetic problems; excellent for swimming, boating 1% Swimming and aesthetic enjoyment of the lake slightly impaired because of algae levels % Desire to swim and level of enjoyment of the lake substantially reduced because of algae levels 99% % 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 Balsam Lake is phosphorus limited, which means that algae and aquatic plant growth is dependent upon available phosphorus. Total phosphorus was evaluated in Balsam Lake in and The data do not indicate much seasonal variability. The majority of the data points fall into the mesotrophic range (Figure 7). Phosphorus should continue to be monitored to track any future changes in water quality. Total Phosphorus (ug/l) Mesotrophic 1 5 Oligotrophic Total Phosphorus 1993, site , site 23 28, site 23 29, site 23 Figure 7. Historical total phosphorus concentrations (ug/l) for Balsam Lake. RMB Environmental Laboratories, Inc. 6 of Balsam Lake

7 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 1 ug/l are perceived as a mild algae bloom, while concentrations greater than 2 ug/l are perceived as a nuisance. Chlorophyll a (ul/l) Chlorophyll a Minor Algae 1993, site , site 23 28, site 23 29, site 23 29, site 23 Chlorophyll a was Figure 8. Chlorophyll a concentrations (ug/l) for Balsam Lake at site 22. evaluated in Balsam Lake in and (Figure 8). Chlorophyll a concentrations were below 1 ug/l in all years, indicating clear water with no algae blooms. There was not much variation over the years monitored and chlorophyll a concentrations remained relatively steady over the summer. Dissolved Oxygen Depth (ft) Dissolved Oxygen (mg/l) Temperature (F) Dissolved Oxygen (mg/l) Water Temperature (F) 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. Balsam Lake is a moderately deep lake, with a maximum depth of 37 feet. Dissolved oxygen profiles from data collected on June 13, 211 show stratification just starting to develop (Figure 9). It was likely too early in the season for the lake to be fully stratified yet. Figure 9. Dissolved oxygen profile for Balsam Lake. RMB Environmental Laboratories, Inc. 7 of Balsam Lake

8 Trophic State Index (TSI) TSI is a standard measure or means for calculating the trophic status or productivity of a lake. More specifically, it is the total weight of living algae (algae biomass) in a waterbody at a specific location and time. Three variables, chlorophyll a, Secchi depth, and total phosphorus, independently estimate algal biomass. 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. If all three TSI numbers are within a few points of each other, they are strongly related. If they are different, there are other dynamics influencing the lake s productivity, and TSI mean should not be reported for the lake. The mean TSI for Balsam Lake falls into the mesotrophic range (Figure 1). There is good agreement between the TSI for phosphorus, chlorophyll a and transparency, indicating that these variables are strongly related (Table 6). Balsam Lake Table 6. Trophic State Index for Balsam. Trophic State Index Site 21 TSI Total Phosphorus 43 TSI Chlorophyll-a 45 TSI Secchi 43 TSI Mean 44 Trophic State: Mesotrophic Numbers represent the mean TSI for each parameter. Hypereutrophic Eutrophic Mesotrophic Oligotrophic Mesotrophic lakes (TSI 4-5) 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. Figure 1. Trophic state index chart with corresponding trophic status. Table 7. Trophic state index attributes and their corresponding fisheries and recreation characteristics. TSI Attributes Fisheries & Recreation <3 Oligotrophy: Clear water, oxygen throughout Trout fisheries dominate the year at the bottom of the lake, very deep cold water. 3-4 Bottom of shallower lakes may become anoxic (no oxygen). Trout fisheries in deep lakes only. Walleye, Cisco present. 4-5 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. 5-6 Eutrophy: Algae and aquatic plant problems possible. "Green" water most of the year. Warm-water fisheries only. Bass may dominate. 6-7 Blue-green algae dominate, algal scums and aquatic plant problems. Dense algae and aquatic plants. Low water clarity may discourage swimming and boating. 7-8 Hypereutrophy: Dense algae and aquatic Water is not suitable for recreation. plants. >8 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. 8 of Balsam Lake

9 Trend Analysis For detecting trends, a minimum of 8-1 years of data with 4 or more readings per season are recommended. Minimum confidence accepted by the MPCA is 9%. This means that there is a 9% chance that the data are showing a true trend and a 1% 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. Balsam Lake had enough data to perform a trend analysis on transparency (Table 8). The data were analyzed using the Mann Kendall Trend Analysis. Table 8. Trend analysis for Balsam Lake. Lake Site Parameter Date Range Trend 23 Total Phosphorus 1993, Insufficient data 23 Chlorophyll a 1993, Insufficient data 21 Transparency No trend 25 Transparency Trend for Balsam Lake 2 Secchi Depth (ft) /27/1992 8/15/1992 8/7/1993 6/11/1994 5/29/1995 7/23/1995 7/6/1996 6/21/1997 6/26/1998 7/1/1999 6/11/2 6/17/21 7/21/21 6/15/22 7/5/23 6/26/24 5/29/25 7/3/25 7/8/26 7/14/27 7/5/28 8/17/28 7/7/29 8/29/29 8/21/21 7/31/211 6/2/213 8/3/213 7/26/214 Figure 11. Transparency (feet) trend for site 21 from Balsam Lake shows no evidence of a transparency trend (Figure 11). This means that the transparency in the lake is stable. Transparency monitoring should continue so that this trend can be tracked in future years. RMB Environmental Laboratories, Inc. 9 of Balsam Lake

10 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. Balsam Lake is in the Northern Lakes and Forest Ecoregion. The mean total phosphorus, chlorophyll a and transparency (Secchi depth) for Balsam Lake are within the ecoregion ranges (Figure 13). Figure 12. Minnesota Ecoregions. 6 3 Total Phosphorus (ug/l, ppb) Chlorophyll-a (ug/l, ppb) Secchi depth (ft) increased algae crystal clear NLF Ecoregion Balsam NLF Ecoregion Balsam 25 CHF Ecoregion Balsam Figure 13. Balsam Lake ranges compared to Northern Lakes and Forest Ecoregion ranges. The Balsam Lake total phosphorus and chlorophyll a ranges are from 16 data points collected in May-September of 1993, The Balsam Lake Secchi depth range is from 137 data points collected in May-September of RMB Environmental Laboratories, Inc. 1 of Balsam Lake

11 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 Grand Rapids 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). Balsam Lake is located in minor watershed 926 (Figure 15). Figure 14. Miss. River- Grand Rapids Major Watershed. Figure 15. Minor Watershed. The MN DNR also has evaluated catchments for each individual lake with greater than 1 acres surface area. These lakesheds (catchments) are the building blocks for the larger scale watersheds. Balsam Lake falls within lakeshed 9262 (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 Figure 16. Balsam Lake lakeshed (9262) with land ownership, lakes, wetlands, and rivers illustrated. RMB Environmental Laboratories, Inc. 11 of Balsam Lake

12 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 Balsam Lake s watershed, containing all the lakesheds upstream of the Balsam Lake lakeshed, see page 17. The data interpretation of the Balsam Lake lakeshed includes only the immediate lakeshed as this area is the land surface that flows directly into Balsam Lake. 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. Balsam Lake lakeshed vitals table. Lakeshed Vitals Rating Lake Area 714 acres descriptive Littoral Zone Area 299 acres descriptive Lake Max Depth 37.5 feet descriptive Lake Mean Depth 15.7 feet descriptive Water Residence Time NA NA Miles of Stream 2.53 miles descriptive Inlets 5 Outlets 1 Major Watershed 9 - Mississippi River-Grand Rapids descriptive Minor Watershed 926 descriptive Lakeshed 9262 descriptive Ecoregion Northern Lakes and Forests descriptive Total Lakeshed to Lake Area Ratio (total lakeshed includes lake area) 6:1 Standard Watershed to Lake Basin Ratio (standard watershed includes lake areas) 37:1 Wetland Coverage (NWI) 17.4% Aquatic Invasive Species Public Drainage Ditches Public Lake Accesses 1 None Miles of Shoreline 1.15 miles descriptive Shoreline Development Index 2.71 Public Land to Private Land Ratio 1:15.2 Development Classification Recreational Development Miles of Road 1.93 miles descriptive Municipalities in lakeshed Forestry Practices None None Feedlots Sewage Management Individual Waste Treatment Systems (septic systems and holding tanks) Lake Management Plan None Lake Vegetation Survey/Plan DNR, 2 RMB Environmental Laboratories, Inc. 12 of Balsam Lake

13 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. Figure 17. Balsam Lake lakeshed (9262) land cover (NLCD 211). Changes in land use, and ultimately land cover, impact the hydrology of a lakeshed. Land cover is also directly related to the land s 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 land s 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 17 depicts the land cover in Balsam Lake s lakeshed. The National Land Cover Dataset (NLCD) has records from 21 and 211. Table 1 describes Balsam Lake s lakeshed land cover statistics and percent change from 21 to 211. Overall, there was not much change over this decade, or from (Table 11). RMB Environmental Laboratories, Inc. 13 of Balsam Lake

14 Table 1. Balsam Lake s lakeshed land cover statistics and % change from 21 to 211 (Data Source: NLCD) % Change Land Cover Acres Percent Acres Percent 21 to 211 Cultivated Crops Deciduous Forest Developed Low Intensity Developed Open Space Emergent Herbaceous Wetlands Evergreen Forest Grassland/Herbaceous Mixed Forest Open Water Pasture/Hay Shrub/Scrub Woody Wetlands Total Area Table 11. Balsam Lake development area and % change from (Data Source: UMN Landsat) % Change Category Acres Percent Acres Percent 199 to 2 Total Impervious Area Urban Acreage Demographics Balsam Lake is classified as a Recreational Development lake. Recreational Development lakes usually have between 6 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 235. Compared to Itasca County as a whole, Balsam Township has a slightly higher growth projection (Figure 18). (source: Percent 9% 8% 7% 6% 5% 4% 3% 2% 1% % Population Growth Projection Compared to 21 Population BalsamTownship; 21 population = 577 Itasca County; 21 population = 45,58 Ec Dev Region; 21 population = 163, Year Figure 18. Population growth projection for adjacent townships, and Itasca County. RMB Environmental Laboratories, Inc. 14 of Balsam Lake

15 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 Balsam Lake s lakeshed is forested uplands (Table 12). This land can be the focus of development and protection efforts in the lakeshed. Table 12. Land ownership, land use/land cover, estimated phosphorus loading, and ideas for protection and restoration in the lakeshed (Sources: County parcel data and the 211 National Land Cover Dataset). Private (75.8) Public (5.) Developed Agriculture Forested Uplands Other Wetlands Open Water County State Federal Land Use (%) Runoff Coefficient Lbs of phosphorus/acre/year Estimated Phosphorus Loading Acreage 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. 15 of Balsam Lake

16 Table 13. Suggested approaches for watershed protection and restoration of DNR-managed fish lakes in Minnesota. Watershed Disturbance (%) Watershed Protected (%) Management Type Comments < 25% > 75% Vigilance < 75% Protection 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%. 25-6% n/a Full Restoration > 6% n/a Partial Restoration 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. Balsam Lake s lakeshed is classified with having 43% of the watershed protected and 7% of the watershed disturbed (Figure 19). Therefore, this lakeshed should have a protection focus. Goals for the lake should be to limit any increase in disturbed land use. Balsam Lake has many other lakesheds flowing into it, but they are well protected (Figure 2). Percent of the Watershed Protected % 1% 75% Balsam Lake (43%) Percent of the Watershed with Disturbed Land Cover % 25% 1% Balsam Lake (6.9%) Figure 19. Balsam Lake s lakeshed percentage of watershed protected and disturbed. Figure 2. Lakesheds that contribute water to the Balsam Lake lakeshed. Color-coded based on management focus (Table 13). RMB Environmental Laboratories, Inc. 16 of Balsam Lake

17 Status of the Fishery (DNR, as of 6/26/26) Balsam Lake is a 71-acre lake located in central Itasca County, north of Taconite, MN. The lake has a maximum depth of 37 ft and a littoral area of 296 acres. One aspect of this survey was to collect data as part of a statewide study evaluating different walleye stocking strategies including fry, fryling and three densities of fingerlings. All stocked fish were marked with oxytetracycline (OTC) to determine the relative contribution of stocked fish and fish from natural reproduction. Walleye gill net catch was.9/net, which was lower than the expected range for similar lakes. Catch rates in past assessments have also been low varying from to 1./gill net. As part of the walleye stocking study, frylings were stocked at a rate of 15/littoral acre in 21, fingerlings were stocked at 2 lbs/littoral acre in 23, and fingerlings were stocked at 1 lb/littoral acre in 25. In 26, 11 fish were aged and only four (36 %) corresponded to stocked year classes. Fish from the 25, year class were likely too small to be sampled effectively and all four fish corresponded to the 23-year class. These fish were also found to carry the OTC marks, confirming that they were stocked fish. Walleye length frequency had two distinct groups; the 23-year class that varied from 12 to 15 inches, and a second group of fish mainly from the year class that varied from 25 to 27 inches. The 1996-year class was a nonstocked year. Back-calculated length at age was not available for the 26 survey, however growth in 24 was similar to the statewide average. Northern pike gill-net catch was 7.1/net, which within the expected range for similar lakes. Gill-net catch rates in past assessments have varied from 3.3 to 1.4/net. Size structure was generally poor and the majority of fish sampled were less than 24 inches. However a few larger fish up to 37 inches were sampled. Balsam Lake has the capability of producing large northern pike, and a 24 to 36 inch protected slot limit was implemented in 26 to improve size structure. Growth was similar to the statewide average with fish averaging 25 inches by age five. Black crappie gill-net catch was 2.6/net, which was toward the upper end of the expected range for similar lakes. Catch rates in past assessments have been highly variable from 2. to 9.1/gill net. Size structure was fairly good with fish up to 1 inches sampled. Recruitment was consistent and all year classes through age 8 were represented. Growth was slower than the statewide average with fish averaging 1 inches by age 8, compared to 12 inches by age 8 for the statewide average. Many of the lakes in this part of the county have a common thread of bog-stained water and slow growing black crappie populations. Bluegill trap net catch rate has been increasing and was 4/net, which was toward the upper end of the expected range for similar lakes. Size structure was poor with few fish exceeding 8 inches. Growth was slower than the lake class average for ages 1 to 6, and faster than the average for ages 7 to 1. Bluegill average 8 inches by age 1. Spring electrofishing sampled largemouth bass at 13.7 fish/hour, which was similar to the 2 catch rate of 18./hr. Fish varied in length from 3 to 16 inches. Growth was similar to the statewide average with fish averaging 15 inches at age seven. Yellow perch gill-net catch was 3.4/gill net and was within the expected range. Catch rates in past assessments varied from.8 to 5.1/net. Size structure was poor with no fish exceeding 9 inches. Other species sampled include tullibee, rock bass, brown bullhead, pumpkinseed, Johnny darter, blackchin shiner, blacknose shiner, bluntnose minnow, golden shiner, longear sunfish, tadpole madtom, and white sucker. The 26 assessment was a full survey, which included vegetation sampling, substrate descriptions and water chemistry. Vegetation sampling described the abundance of 49 different RMB Environmental Laboratories, Inc. 17 of Balsam Lake

18 aquatic and riparian plant species. Substrate was primarily sand and detritus with lesser amounts of rubble and gravel. Water chemistry analysis indicated total phosphorous of.3 ppm and total alkalinity of 91 ppm. Lakeshore owners may affect fish populations not only through harvesting fish, but also through land use practices. It is important to leave a 3 to 5 ft buffer strip of native vegetation along the shoreline to prevent erosion and provide habitat for fish and wildlife. Nonfunctioning septic systems can also lead to water quality problems. Good water quality and fish populations are the direct result of good land use practices. Anglers can also help to improve the size structure of the fish community by practicing selective harvest. See the link below for specific information on gillnet surveys, stocking information, and fish consumption guidelines. Key Findings / Recommendations Monitoring Recommendations Transparency monitoring at sites 21 and 23 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. Total Phosphorus and chlorophyll a monitoring should continue, as the budget allows, to track trends in water quality. The inlets to Balsam Lake appear to be minor, but if they are suspected as phosphorus sources to the lake they could be monitored for phosphorus. Overall Summary Balsam Lake is a eutrophic lake (TSI = 44) with no evidence of trends in water quality, which means the water quality is stable. The total phosphorus, chlorophyll a and transparency ranges are within the ecoregion ranges. Only nine percent (7%) of the Balsam Lake lakeshed is disturbed by development and agriculture (Figure 19). The threshold of disturbance where water quality tends to decline is 25%. Balsam Lake is well under this threshold. Almost half (43%) of the lakeshed is protected (Figure 19) (public land or wetlands) which protects that land from development. Of the privately owned land, 48% of it is forested, which is good for water quality. Priority Impacts to the Lake The priority impact to Balsam Lake would be the expansion of residential housing development along the lakeshore. The conversion of small lake cabins to year-round family homes increases the impervious surface and runoff from the lake lots. Most of the private land around the lake is only lightly developed in the first tier. Overall, the development pressure for Balsam Lake appears low. Data from and show there wasn t much increase in development during that period of time (Tables 1-11). Best Management Practices Recommendations The management focus for Balsam Lake should be to protect the current water quality and lakeshed. Efforts should be focused on managing and/or decreasing the impact caused by additional development, and impervious surface area on existing lots (conversion of seasonal cabins to year-round homes). RMB Environmental Laboratories, Inc. 18 of Balsam Lake

19 The current lakeshore homeowners can lessen their negative impact on water quality by installing or maintaining the existing trees on their properties. Forested uplands contribute significantly less phosphorus (lbs/acre/year) than developed land cover (Table 12). Forested uplands can be managed with Forest Stewardship Planning. In addition, filter strips or native vegetative buffers could be installed to decrease or slow the runoff reaching the water s edge. Septic systems should be pumped and inspected regularly. The lakeshed still has large undeveloped shoreline parcels (Figure 16). Because a lot of undeveloped private land still exists, there is a great potential for protecting this land with conservation easements and aquatic management areas (AMAs). Conservation easements can be set up easily and with little cost with help from organizations such as the Board of Soil and Water Resources and the Minnesota Land Trust. AMAs can be set up through the local DNR fisheries office. 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) Conservation easements Lake Associations Lake condition monitoring Ground truthing visual inspection upstream on stream inlets Watershed runoff mapping by a consultant Shoreline inventory study by a consultant Conservation easements Soil and Water Conservation District (SWCD) and Natural Resources Conservation Service (NRCS) Shoreline restoration Stream buffers Wetland restoration Forest stewardship planning Work with farmers to o Restore wetlands o Implement conservation farming practices o Land retirement programs such as Conservation Reserve Program RMB Environmental Laboratories, Inc. 19 of Balsam Lake

20 Organizational contacts and reference sites Itasca County Environmental Services Department Itasca Soil and Water Conservation District DNR Fisheries Office Regional Minnesota Pollution Control Agency Office Regional Board of Soil and Water Resources Office 124 NE 4 th St., Grand Rapids, MN (218) East Highway 2, Grand Rapids, MN (218) East Highway 2, Grand Rapids, MN (218) Lake Avenue South, Duluth, MN 5582 (218) Minnesota Drive, Brainerd, MN 5641 (218) RMB Environmental Laboratories, Inc. 2 of Balsam Lake