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HomeMy WebLinkAbout01_2025 Arrowhead Score Your Shore Final Report2025 ARROWHEAD LAKE SCORE YOUR SHORE ASSESSMENT City of Edina Edge Aquatic Services, LLC Shoreline Importance The shoreline is where land and water meet, providing an especially rich life zone for birds, pollinators, fish, and other animals. The shoreline itself is part of a larger natural community and ecosystem. When living on a lake, how you manage your shoreline, directly impacts the water quality in that lake and the fisheries and wildlife found there. Healthy, more natural shorelines are vital to good water quality in a lake and provide many benefits to homeowners and the lake. 1. Native vegetation stabilizes shorelines and reduces erosion a. Native vegetation has deeper roots that help stabilize soils more than turf grass b. Protects against wind and wave action 2. The deep root system of native vegetation filters run off preventing nutrients and sediment from flowing into a lake 3. Trees and vegetation provide homeowners privacy 4. Natural shorelines discourage large flocks of geese gathering on lawns 5. Native shoreline vegetation provides habitat for pollinators and dragonflies a. Dragonflies are predators of mosquitoes helping with control When shorelines are turf grass all the way to the water’s edge, there are no deep roots to hold the soil in place. Thus, a lot of sediment washes into the lake - twelve times more than with a natural shoreline. Sediment contains a lot of phosphorus and phosphorus leads to an increase in algae growth. Score Your Shore Tool Score Your Shore is a tool developed by the Minnesota Department of Natural Resources (MNDNR) to assess shoreline health on developed parcels around Arrowhead Lake. The assessment scores 3 shoreline zones: Upland Zone, Shoreline Zone, and Aquatic Zone (Figure 1). Figure 1. Three zones assessed in the Score Your Shore Assessment. Photo from the MNDNR. Each zone has its own scoring rubric. The upland zone is assessed on trees, shrubs, and natural ground cover with a maximum score of 65 points (Figure 2). The shoreline zone is assessed on trees & shrubs and natural ground cover with a maximum score of 35 (Figure 3) and dominate shoreline type was noted (natural, mowed, rip rap, etc.). The aquatic zone is assessed on emergent/floating leaf aquatic vegetation, submerged aquatic vegetation, overhanging vegetation, and downed woody habitat with a maximum score of 100 (Figure 4). The total maximum score a property can receive is 200. Impervious surfaces such as pathways, sheds, or patios, manicured lawns, removal of aquatic vegetation, etc. decrease overall score for each zone. Figure 2. Upland zone scoring rubric developed by the MNDNR. Figure 3. Shoreline zone scoring rubric developed by the MNDNR. Figure 4. Aquatic zone scoring rubric developed by the MNDNR. Results The Arrowhead Lake Score Your Shore survey was completed on 6/28/2025. 40 parcels were evaluated using the rubric above. The results are divided into a series of tables and maps based on each zone surveyed. Terrestrial Zone Results The terrestrial zone consists of the upland and shoreline zones. Below are results for each zone. Upland Zone Results Natural upland areas provide many benefits for lake health. It reduces erosion by holding sediments, large root systems promote runoff infiltration and the uptake of nutrients and provides habitat for wildlife. The maximum score for the upland zone is 65. Table 1 shows the percentage of parcels in each grade for upland zone categories. Table 2 combines upland trees, shrubs, and ground cover scores into an upland zone total score and quantifies the proportion of properties with high quality habitat and those that need improvement. Figure 5 shows the upland tree grade for each Arrowhead Lake parcel. Figure 6 shows the upland shrub grade for each parcel. Figure 7 shows the ground cover grade for each parcel. Figure 8 shows the total upland zone score, which is the combination of upland trees, shrubs, and ground cover scores. Table 1. Proportion of 40 Arrowhead Lake parcels grades for upland zone categories. Grade % of Lot Trees Shrubs Ground Cover A 75-100 32.50% 42.50% 50.00% B 50-75 20.00% 12.50% 10.00% C 25-50 22.50% 17.50% 12.50% D 1-24 25.00% 15.00% 0.00% F 0 0.00% 12.50% 27.50% Table 2. Combines upland trees, shrubs, and ground cover scores into an upland zone total score. Total Upland Zone Rating Score Range % of Lots High 50-65 45.00% Moderate 35-50 15.00% Low 20-35 17.50% Very Low 0-20 22.50% Figure 5. 2025 Arrowhead Lake upland zone trees scores. 32.5% of parcels scored an A, 20% scored a B, 22.5% scored a C, and 25% scored a D. Figure 6. 2025 Arrowhead Lake upland zone shrubs scores. 42.5% of parcels scored an A, 12.5% scored a B, 17.5% scored a C, 15% scored a D, and 12.5% scored a F. Figure 7. 2025 Arrowhead Lake upland zone ground cover scores. 50% of parcels scored an A, 10% scored a B, 12.5% scored a C, 0% scored a D, and 27.5% scored a F. Figure 8. 2025 upland zone total scores. Shoreline Zone Results Natural shorelines provide many benefits for lake health. It reduces erosion by holding sediments, large root systems promote runoff infiltration and the uptake of nutrients and provides habitat for wildlife. The maximum score for the shoreline zone is 35. Table 3 shows the percentage of parcels in each grade for shoreline zone categories. Table 4 combines shoreline trees, shrubs, and ground cover scores into a shoreline zone total score and quantifies the proportion of properties with high quality habitat and those that need improvement. Table 5 lists the different shoreline types found around Arrowhead Lake and the percentage of parcels with that shoreline type. Figure 9 shows the shoreline tree and shrub grade for each Arrowhead Lake parcel. Figure 10 shows the shoreline ground cover grade for each parcel. Figure 11 shows the total shoreline zone score, which is the combination of shoreline trees, shrubs, and ground cover scores. Figure 12 shows the dominant shoreline type for each parcel. Table 3. Proportion of 40 Arrowhead Lake parcels grades for shoreline categories. Grade % of Lot Trees & Shrubs Ground Cover A 75-100 30.00% 75.00% B 50-75 22.50% 5.00% C 25-50 17.50% 7.50% D 1-24 17.50% 5.00% F 0 12.50% 7.50% Table 4. Combines shoreline trees, shrubs, and ground cover scores into a shoreline zone total score. Total Shoreline Zone Rating Score Range % of Lots High 30-35 50.00% Moderate 20-30 22.50% Low 10-20 15.00% Very Low 0-10 12.50% Table 5. Lists the different shoreline types found around Arrowhead Lake and the percentage of parcels with that shoreline type. Dominant Shoreline % of Parcels Beach 5.00% Mowed 15.00% Natural 80.00% Figure 9. 2025 Arrowhead Lake shoreline tree and shrub scores. 30% of parcels scored an A, 22.5% scored a B, 17.5% scored a C, 17.5% scored a D, and 12.5% scored a F. Figure 10. 2025 Arrowhead Lake shoreline ground cover scores. 75% of parcels scored an A, 5% scored a B, 7.5% scored a C, 5% scored a D, and 7.5% scored a F. Figure 11. 2025 Arrowhead Lake shoreline zone total scores. Figure 12. Dominate shoreline type for Arrowhead Lake parcels. Terrestrial Zone Total Results Table 6 combines upland and shoreline zone scores for a total terrestrial and quantifies the proportion of properties with high quality habitat and those that need improvement. Figure 13 shows the total terrestrial score for each Arrowhead Lake parcel. Table 6. Combined upland and shoreline zone scores for a total terrestrial score and the percentage of parcels in each rating. Total Terrestrial Rating Score Range % of Lots High 85-100 35.00% Moderate 65-85 22.50% Low 25-65 30.00% Very Low 0-25 12.50% Figure 13. 2025 Arrowhead Lake terrestrial zone total scores. Aquatic Zone Results The aquatic zone consists of emergent and floating aquatic vegetation, submerged aquatic vegetation, artificial openings in aquatic vegetation, overhanging terrestrial vegetation, and downed woody vegetation. Below are results for each zone. Emergent and Floating Aquatic Vegetation Results Emergent and floating aquatic vegetation is extremely important for shoreline health and provides many benefits. It reduces erosion by decreasing wave action, it absorbs nutrients from runoff, and it provides habitat for fish and wildlife. The maximum score for emergent and floating vegetation is 40. Table 7 shows the percentage of Arrowhead Lake Parcel grades for emergent and floating aquatic vegetation. Figure 14 shows the emergent and floating aquatic vegetation scores for each Arrowhead Lake parcel. Table 7. Proportion of 40 Arrowhead Lake parcels grades for emergent and floating vegetation. Grade % of Shoreline Score % of Lots A 75-100 40 60.00% B 50-75 30 10.00% C 25-50 20 22.50% D 1-24 10 7.50% F 0 0 0.00% Figure 14. 2025 Arrowhead Lake aquatic zone emergent and floating vegetation scores. 60% of parcels scored an A, 10% scored a B, 22.5% scored a C, 7.5% scored a D, and 0% scored a F. Submerged Aquatic Vegetation Results Submerged aquatic vegetation is extremely important for shoreline health and provides many benefits. It reduces erosion by decreasing wave action, it absorbs nutrients from runoff, and it provides habitat for fish and wildlife. The maximum score for aquatic vegetation is 35. Table 8 shows the percentage of Arrowhead Lake Parcel scores for submerged aquatic vegetation. Figure 15 shows the submerged aquatic vegetation scores for each Arrowhead Lake parcel. Table 8. Proportion of 40 Arrowhead Lake parcels scores for submerged aquatic vegetation. Rating Score % of Lots Abundant 35 72.50% Sparse 15 27.50% Absent 0 0.00% Figure 15. 2025 Arrowhead Lake aquatic zone submerged aquatic vegetation scores. 72.5% of parcels scored abundant, 27.5% scored sparse, and 0% scored absent. Openings in Aquatic Vegetation Results Unnatural openings in aquatic vegetation are areas in submerged vegetation that have been removed by landowners. Openings can be used for watercraft navigation or a beach area. The maximum score is 5. Table 9 shows the percentage of Arrowhead Lake Parcel scores for unnatural openings in submerged aquatic vegetation stands. Figure 16 shows the openings in submerged aquatic vegetation scores for each Arrowhead Lake parcel. Table 9. Proportion of 40 Arrowhead Lake parcels scores for unnatural openings in submerged aquatic vegetation. Rating Score % of Lots No Opening 5 95.00% Opening Present 0 5.00% Figure 16. 2025 Arrowhead Lake aquatic zone unnatural openings in submerged aquatic vegetation. 95% of parcels exhibited no opening and 5% exhibited an unnatural opening. Overhanging Terrestrial Vegetation Results Overhanging terrestrial vegetation describes vegetation that hangs from the shoreline into the surface of the water. It provides habitat for fish, macroinvertebrates, and other wildlife. Maximum score is 10. Table 10 shows the percentage of Arrowhead Lake Parcel scores for overhanging vegetation. Figure 17 shows overhanging vegetation scores for each Arrowhead Lake parcel. Table 10. Proportion of 40 Arrowhead Lake parcels scores for overhanging vegetation. Rating Score % of Lots Present 10 95.00% Absent 0 5.00% Figure 17. 2025 Arrowhead Lake aquatic zone overhanging vegetation. 95% of parcels exhibited overhanging vegetation and 5% exhibited no overhanging vegetation. Downed Woody Vegetation Results Downed woody vegetation describes fallen trees and shrubs that residents have left in the water. Like overhanging vegetation downed woody vegetation provides habitat for fish, macroinvertebrates, and other wildlife. Maximum score is 10. Table 11 shows the percentage of Arrowhead Lake Parcel scores for downed woody habitat. Figure 18 shows downed woody habitat scores for each Arrowhead Lake parcel. Table 11. Proportion of 40 Arrowhead Lake parcels scores for downed woody habitat. Rating Score % of Lots Present 10 30.00% Absent 0 70.00% Figure 18. 2025 Arrowhead Lake aquatic zone downed woody vegetation. 30% of parcels exhibited downed woody vegetation and 70% exhibited no downed woody vegetation. Total Aquatic Zone Results Table 12 combines emergent and floating aquatic vegetation, submerged aquatic vegetation, artificial openings in aquatic vegetation, overhanging terrestrial vegetation, and downed woody vegetation and shows the proportion of properties with high quality habitat and those that need improvement. The maximum score is 100. Figure 19 shows the total aquatic zones score for each Arrowhead Lake parcel. Table 12. Combined all aquatic zone scores for a total aquatic zone score and the percentage of parcels in each rating. Total Aquatic Zone Score Score Range % of Lots High 85-100 52.50% Moderate 65-85 25.00% Low 25-65 22.50% Very Low 0-25 0.00% Figure 19. 2025 Arrowhead Lake aquatic zone total scores. Total Score The total score combines terrestrial and aquatic zone scores. The maximum score is 200. Table 13. Total scores and the percentage of parcels in each rating. Rating Score Range % of Lots High 170-200 37.50% Moderate 130-170 27.50% Low 50-130 35.00% Very Low 0-50 0.00% Figure 20. 2025 Arrowhead Lake total scores. Appendix Table 14. Individual property scores labeled with parcel ID. PID Upland Trees Upland Shrubs Upland Ground Shoreline Trees & Shrubs Shoreline Ground Emergent and Floating Aquatic Vegetation Submerged Aquatic Vegetation Unnatural Openings Overhanging Terrestrial Vegetation Downed Woody Habitat Dominant Shoreline 0611621210068 13 10 0 10 7 10 35 0 10 0 Mowed 0611621210069 25 20 20 5 15 20 35 5 10 0 Natural 0611621210114 18 5 20 15 15 40 35 5 10 0 Natural 0611621210115 18 5 15 15 12 40 35 5 10 0 Natural 0611621210116 25 15 20 15 15 40 35 5 10 10 Natural 0611621220012 9 0 0 5 15 40 15 5 10 0 Natural 0611621220013 9 15 10 5 15 40 35 5 10 0 Natural 0611621220014 9 10 15 0 15 40 35 5 10 10 Natural 0611621220017 18 15 10 0 15 40 15 5 10 0 Natural 0611621220020 9 5 0 5 4 10 15 5 10 0 Mowed 0611621220021 9 0 0 0 0 30 15 5 10 0 Natural 0611621220056 9 10 15 0 15 20 15 5 0 0 Natural 0611621220057 25 20 20 20 15 30 35 5 10 0 Natural 0611621220058 25 20 20 20 15 40 15 5 10 0 Natural 0611621220059 13 5 0 20 15 20 15 5 10 0 Natural 0611621230008 13 10 0 10 7 10 15 5 10 10 Mowed 0611621230012 13 20 20 15 15 20 35 5 10 10 Natural 0611621230014 13 5 0 5 0 20 35 5 10 0 Mowed 0611621230015 13 20 20 15 15 40 35 5 10 0 Natural 0611621230023 18 20 20 10 15 40 35 5 10 0 Natural 0611621230024 25 20 20 20 15 40 35 5 10 0 Natural 0611621230025 18 15 10 15 15 40 35 5 10 0 Natural 0611621230029 9 0 0 5 4 40 15 5 10 0 Mowed 0611621230056 25 20 20 20 15 40 35 5 10 0 Natural 0611621230060 18 20 20 5 15 30 35 5 10 0 Natural 0611621230061 9 5 0 10 15 20 35 5 10 10 Natural 0611621230062 13 10 10 15 15 40 35 5 10 10 Natural 0611621240001 9 10 10 10 7 20 15 5 10 0 Beach 0611621240006 25 20 20 20 15 40 35 5 10 0 Natural 0611621240008 25 20 20 20 15 40 35 5 10 10 Natural 0611621240009 18 15 15 10 12 20 15 0 10 0 Beach 0611621240025 13 10 20 10 15 40 35 5 10 10 Natural 0611621240026 25 20 20 20 15 40 35 5 10 0 Natural 0611621240030 18 20 20 15 15 40 35 5 10 10 Natural 0611621240031 25 20 20 20 15 30 35 5 10 10 Natural 0611621240033 13 0 0 15 15 40 35 5 10 0 Natural 0611621240034 9 0 0 0 0 20 35 5 0 0 Mowed 0611621240035 25 20 20 20 15 40 35 5 10 10 Natural 0611621240038 25 20 20 20 15 40 35 5 10 0 Natural 0611621240039 25 20 20 20 15 40 35 5 10 10 Natural Figure 21. Arrowhead Lake parcels labeled with PIDs.