The Grassval series consists of shallow and very shallow over indurated duripan, well drained soils that formed in alluvium from mixed rock sources.
Grassval soils occur on fan piedmont remnants.
Slopes are 2 to l5 percent. Grassval fine sandy loam, rangeland. The surface is covered with approximately 10 percent gravel. Mildly alkaline or moderately alkaline. Moderately alkaline or strongly alkaline.