Lake Sarah (Hennepin County) Outlet Investigation

Lake Sarah has been experiencing higher lake levels for several years. The lake has been consistently above its Ordinary High Water (OHW) level since regular lake level readings have been kept since 1994. The DNR Waters Area Hydrologist and the Cities of Greenfield and Independence have received numerous high water complaints, primarily in regard to shoreline erosion and yard damage from higher lake levels. The outlet is located at the northwest end of the lake and flows through a relatively flat wetland/upland reach, eventually reaching the Crow River, approximately two miles downstream of Lake Sarah (Figure 1). The current runout is located at an abandoned railroad grade. The City of Greenfield produced plans to excavate sediment from a 3100-foot reach of the outlet channel to minimize higher water conditions. Concerns about the potential of this proposal to excessively lower lake levels, and impact a protected wetland (27-365W) immediately downstream of Lake Sarah, prompted this investigation.