NRCS Maine State Office - Conceptual and Final Designs For Proposed Fishway

The Maine NRCS would like to provide aquatic organism passage around the existing 145 feet long dam at the outlet of Sanborn Pond to improve stream connectivity for a variety of aquatic species (Maine Gazetteer Map 14-A3). The existing dam is approximately 7 ft. tall and is composed of boulders, hemlock planks and unreinforced concrete over bedrock. The bedrock is exposed along the river left bank upstream of the dam and underneath the dam which will provide a solid foundation for the proposed fishway. The dam is located approximately 450 feet upstream of Route 137; the dam is privately owned and is currently a complete barrier to aquatic organism passage. The work consists of providing up to three different conceptual fishway designs and one finalized fishway design. The fishway should be able to accommodate a multitude of aquatic species at different flowrates during upstream and downstream migration; alewives will be the target species. The design services required at the Sanborn Pond Outlet include preparing the following for the fishway design: Site inspection Review of existing surveys completed by the NRCS and partners Hydrologic calculations for the proposed fishway including the low flow (7Q10), mean and median monthly flows, flows during upstream and downstream passages seasons and the following flood flows: bankfull, 2-year, 5-year, 10-year, 25-year, 100-year and 500-year storm events. Analysis of potential fishway options at the site and conceptual design (30% complete designs) for up to three fishway structures. The conceptual design should include the proposed fishway, appurtenances and any instream work that is potentially needed. A conceptual design report detailing proposed fishway options and preliminary calculations will be submitted with the designs to the NRCS for review and comment. Design meetings with the NRCS and partners to discuss conceptual and final designs. A public meeting outlining the conceptual options. Hydraulic analysis at the proposed fishway location including an estimated range of water levels and flows to account for seasonal fluctuations in the pond. The final engineering design shall include a design report including hydrologic and hydraulic calculations and all supporting calculations for the fish passage design based on fish passage criteria developed by the NOAA Fisheries and U.S. Fish and Wildlife Service. Final PE stamped design drawings of the fishway which includes a site plan showing the full extent of project activities including mobilization, erosion and sediment control areas, stockpile areas and fishway. Engineer's itemized opinion of cost and probable schedule of events. A completed bid package that can be issued to contractors.