2.2.2 Geology and Soils

The depth to bedrock within the subwatershed varies from 200 to 300 feet in the northern half of the subwatershed to 100-200 feet in the southern half.  Quaternary deposits - the surficial material overlaying the bedrock - are distinctly different from north to south.  The area to the north is mainly high relief New Ulm loamy till, with pockets of peat.  A large area through the central subwatershed to the north and east of Gleason Lake was deposited with sandy and gravelly outwash sediment.  South of Gleason Lake deposits of peat, muck, and lake clay dominate, although areas of sandy till are present as well.  Soils within the watershed are predominantly classified as Natural Resources Conservation Service Hydrologic Soil Group B (loamy soils with moderate infiltration potential) and D (clayey soils with very low infiltration potential) (see Figure 3).  The Group D soils are found in low-lying areas and are generally hydric, or showing indications of inundation (see Figure 4).