Ipava and Keomah soils are on similar nearby landscapes and form a biosequence with Clarksdale soils. The poorly drained Rushville soils do not have a dark surface layer and are on nearly level or slightly depressional areas. The poorly drained Sable soils have mollic epipedons and are typically on broad upland areas farther from the dissecting drainageways than Clarksdale soils. Somewhat poorly drained. Surface runoff potential is slow to medium.
Permeability is moderately slow.
In undisturbed areas the seasonal high water table is above 20 inches for some time in most years. Where artificially drained it is above a depth of 36 inches for short periods in spring in most years. Soils are used to grow corn, soybeans, small grain, and hay. Natural vegetation is grass and deciduous hardwood forest. Central and western Illinois.