2.2.1 Topography and Drainage
The eastern half of the subwatershed is located within the Emmons-Faribault moraine geomorphic region, and the topography is typical of that region – gentle rolling hills with an abundance of lakes and ponds, reflected in the area’s many wetlands. The western half is within the Lonsdale-Lerdal till region, an area characterized by thinly spread glacial drift and circular, level-topped hills. The 2003 MCWD Hydrologic, Hydraulic, and Pollutant Loading Study (HHPLS) subdivided the Long Lake subwatershed into 53 subwatershed units, designated LLC-1 through LLC-53 (see Figure 2).
Long Lake is fed by two main drainage corridors originating in the northwestern corner from School Lake, and in the northeastern corner from Holy Name Lake. A tributary from School Lake drains the northwestern upper subwatershed and flows through several wetlands and Wolsfeld Lake. A tributary from Holy Name Lake flows through wetlands before joining with the western tributary just south of Wolsfeld Lake. That stream continues south and flows into the north end of Long Lake. Additional, smaller drainage areas to the west of the lake include Dickey’s Lake, and the City of Long Lake/US Highway 12 area that flows through a ravine that flows into Long Lake through the Park Ponds, District-constructed water quality ponds.
Long Lake Creek flows 2.7 miles from the southern end of Long Lake through several wetlands and Tanager Lake prior to discharging into Browns Bay.
Two significant areas within the subwatershed are landlocked. Units LLC-21, 22, and 23, which include Mooney Lake and Lydiard Lake, have no natural outlet. Mooney Lake is pumped out when certain agreed-upon conditions occur. Units LLC-40, 42, and 43 contain wetlands that have no or limited outlet.