The moderate but somewhat erratic rainfall is the source of water for crops and range. Summer droughts are common. The larger rivers, such as the Brazos and Colorado Rivers, flow most of the year, but local streams flow intermittently. There are several large lakes and numerous flood-detention, reservoirs in the area. Livestock water comes from streams or ponds.
Ground water is scarce.
Most of the soils are Ustolls, Usterts, Ustalfs, and Ochrepts. These soils are well drained and moderately well drained, somewhat stony, and medium textured to fine textured. They have a thermic temperature regime, an ustic moisture regime, and mixed or montmorillonitic mineralogy. The Potential vegetation is rather uniform throughout the area despite the wide variation in soils. Little bluestem, indiangrass, big bluestem, sideoats grama, hairy grama, and Texas wintergrass are the dominant grass species.