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I ~ I I I I ,I I I I I I I . I I I I I I I o A levee is proposed to be constructed from near the east abutment of State Highway 9 downstream to the vicinity of Lincoln Street where either alluvial soils or Dempster soils are located. o A levee is proposed to be constructed from near the east abutment of State Highway 9 to north of Pearl Street which is north of Highway 9 where mostly Dempster soils are located. o A levee is proposed to be constructed north of North Fourth Avenue along the existing berm alignment extending to high ground where Kennebec soils are located on the western half of the proposed levee, Dempster soils were located in the center, and Davis soils are located on the eastern half. o A levee is proposed to be constructed along the railroad north of North Second Avenue and consists of Colo soils on the western half of the proposed levee and Kennebec soils on the eastern half. A discussion of the soils and their properties identified within the areas of the proposed levees are presented below. There are six different types of soils identified in the Soil Survey of Lyon County, Iowa, by the USDA. The soils identified as Davis loam or silty loam consist of silt, are fine grained, low plastic, and are dark gray to black in color. The water table depth is assumed to be over 5 feet deep in areas of this soil type. The permeability ranges from 0.6 to 2.0 inches per hour for Davis loam or silty loam. The Dempster series soils range from silty clay loam from the surface to about 3 feet below the surface to sand and gravel below the 3-foot level. The Dempster silty clay loam consists of clay, is sandy, low plastic, and is very dark brown in color with a permeability ranging from 0.6 to 2,0 inches per hour, The Dempster sand and gravel consists of sand with gravel, is non plastic, and is brown with a permeability of over 6 inches per hour. The water table depth in the areas associated 9