Watershed ManagementBuffer strips/ErosionSeptic SystemsIn-Lake ManagementMonitoring and RegulationCommunity Awareness and EducationGrants and FundingThreemile Pond RecommendationsThe primary problem facing Threemile Pond is cultural eutrophication. Increased development along the shore accelerates the loading of phosphorus and nitrogen into Threemile Pond. Additionally, the excess phosphorus in the sediment of Threemile Pond is recycled through the water column and made available for plant growth by internal loading. Remediation efforts targeted to limit the quantities of available nutrients must address both of these nutrient sources. The Maine DEP classifies Threemile Pond as eutrophic. Although water quality has not seen a serious decline in recent years, it remains relatively poor. The implementation of preventative measures is essential to improve the water quality of Threemile Pond. The Colby EnvironmentalAssessment Team has developed these recommendations to help address this issue.Watershed ManagementBuffer strips/Erosion- Many shoreline lots have inadequate buffer strips. To minimize phosphorus runoff intothe lake, these buffer strips should be improved:- Cover the length of the shoreline with native shrubs, grasses, and trees.- Allow the buffer to stretch as far back as possible from the lake.- Protect the shoreline itself from erosion with aquatic plants and riprap.- Future building and development must be carefully planned to:- Minimize potential nutrient loading in areas with high erosion potential. - Minimize impervious surfaces like roofs, parking lots, and driveways near theshoreline.Roads- Camp roads should be regularly maintained and improved, with a focus on the problemareas identified in this study. Conduct frequent road surveys to identify new troublespots.- Highest priority for improvement should be assigned to roads in close proximity to thelake, due to their greater potential to contribute phosphorus to the lake.- Hire certified contractors to conduct all roadwork and follow DEP guidelines.- For all road construction, maintenance, and improvement, measures such as grading,crowning, ditching, and diversions should be utilized to limit sediment runoff. Removeberms along road edges to prevent water retention and formation of potholes and rills.- Minimize all road construction within the shoreline zone. Septic Systems- Homeowners can minimize septic system impact on Threemile Pond by:- Following all local and state septic regulations. - Regularly checking and pumping septic tanks when necessary. - Upgrading or replacing the subsurface wastewater disposal systems when thesesystems fail or when the property is expanded or winterized.Land Use- Limit shoreline development and enforce regulations- Monitor new residential and commercial development to ensure compliance with codesand regulation- Retain forested areas, especially on the shoreline to help buffer phosphorus inflow to thelake- Surround cleared areas with silt fences or hay to prevent erosion and phosphorus runoffBoat ramp- Use the public boat launch. All boats should be launched from the public boat launch andthen driven to homeowners' mooring or dock. Private, unpaved boat launches aresignificant sources of erosion and runoff. - Consider enhancements to the public boat launch that would minimize potentialphosphorus loading.In-Lake Management- Phosphorus inputs to the lake should be minimized or stopped before implementingmitigation techniques- The phosphorus loading model predicted that at least 35 percent of the phosphorus inThreemile Pond was due to internal nutrient recycling, making it the greatest contributor. Even if the amount of incoming phosphorus to Threemile Pond is limited, phosphoruslevels will remain high and still sustain algal blooms. In-lake remediation techniques canbe expensive, but the eutrophic status of Threemile Pond may demand such mitigation.Three possibilities for mitigation should be investigated:- Biological manipulation through fish stocking is a practical and less costly meansof potentially controlling the phytoplankton population and improving lake waterquality.- Hypolimnetic aeration could reduce or prevent phosphorus-releasing anaerobicconditions by augmenting dissolved oxygen levels in the deeper parts of the lake.- With proper management and specific application, an alum treatment couldeffectively reduce the amount of phosphorus in the sediment available for release.Monitoring and Regulation- Consistent monitoring of phosphorus levels and transparency should occur throughout thespring, summer, and fall. Continue participation in Maine Volunteer Lake Monitoring Program.- Residents should limit phosphorus entering Threemile Pond by only using low phosphorus fertilizer on shoreline areas. Shoreline residents could also consider using low phosphate soap and detergent.- We suggest protecting existing wetlands to maintain their capacity as a natural buffer. Maintain high standards for future shoreline development that protect existing wetlands.- Residents should continue to support the work of the Threemile Pond Association and China Region Lakes Alliance.- We also suggest continuing consideration of regulating the maximum annual phosphorusload allowed from each lot.Community Awareness and Education- Residents living within the Threemile Pond watershed have a great impact on the overallhealth of the lake. Further education could provide residents with the tools to reduce theimpact of individual residences.- The China Lakes Region Alliance, along with the towns of China, Vassalboro, andWindsor, could host watershed education workshops for community members. Theworkshops could help enhance community understanding of the issues affecting lakewater quality through discussions and hands-on activities.- The China Lakes Region Alliance and other organizations could provide communitydemonstrations of best management practices. These demonstrations would provide thecommunity with an opportunity to see how individuals can help control non-point sourcepollution.- Fact sheets and brochures could be distributed to homeowners living within thewatershed. These sheets could provide the community with information about watershedhealth and practices that lessen residential impact on the watershed.-