2.2.2 Geology and Soils

The depth to bedrock within the subwatershed varies from 200 to 400 feet.  Quaternary deposits – the surficial material overlaying the bedrock – are generally high relief New Ulm loamy till common to the upper watershed, with pockets of peat and muck and a few isolated pockets of clay deposits.    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) or are in areas of mucky soils.  There are also scattered areas of Group C soils, finer-grained soils with low infiltration potential.