3322 KROMER AVE Geotech Report 2023-05-25

GeoTest Services, Inc.—Revision 1 April 10, 2020 Kikuchi Retaining Wall, Everett, Washington Project No. 20-0344 Groundwater levels are variable and groundwater conditions will fluctuate depending on local subsurface conditions, precipitation, and changes in on-site and off-site use. Soil Survey According to the United States Department of Agriculture (USDA) Natural Resource Conservation Service website, soils within the vicinity of the subject property are classified as Indianola loamy sand and Alderwood-Urban land complex. Indianola loamy sand soils are derived from a parent material of sandy glacial outwash. These soil units are somewhat excessively drained.An erosion susceptibility K factor is not given for this soil type. Values of K range from 0.02 to 0.69; the higher the value, the more susceptible the soil is to sheet and rill erosion by water. Indianola soils have a Land Capability Classification of "e". This subclass is made up of soils where erosion is the dominant problem or hazard in their use (USDA, 1961). Thus, the USDA classification would suggest that some erosion mitigation would be needed if development occurs near the slope. Alderwood-Urban land complex soils are derived from a parent material of basal till. The soil profile consists predominately of gravelly loam on 25 to 65 percent slopes. These soil units are moderately well drained and have a lower potential for erosion with a susceptibility (K factor) of 0.05. Table 1 summarizes the soil properties obtained from the USDA Web Soil Survey website. Table 1 USDA Web Soil Survey Soil Classifications Map Unit Symbol 26 5 Map Unit Name Indianola Alderwood-Urban land complex Soil Description Loamy sand, 15 to 30 percent slopes Gravelly loam,25 to 65 percent slopes Landform Eskers, kames,terraces Till plains Parent Material Sandy glacial outwash Basal till Land Capability Classification 4e 4s Erosion K Factor, Whole Soil -- 0.05 7