Wann soils formed in stratified, calcareous, alluvium along major streams. They have slopes of 0 to 2 percent and commonly occur in the lower part of the landscape. In Colorado mean annual precipitation ranges down to 11 inches. These include the Alda , Cass , Darr , Inavale , Lamo , Leshara , Lex , Ord , and Platte soils all on a similiar flood plain. Lex soils have coarse sand or gravelly sand between a depth of 20 to 40 inches.
Inavale soils are coarser textured and better drained.
Cass soils are better drained. Darr soils are better drained and have coarse sand or gravelly sand between a depth of 20 to 40 inches. Lamo and Leshara soils are fine-silty. Platte soils are shallow to coarse sand, gravelly sand or gravelly coarse sand. Ord soils have sand at 20 to 35 inches and are more clacareous.