These plains are nearly level but smooth hills and valleys are gently rolling. The valleys are narrow to broad. The hills are mostly in the east. Average annual precipitation -625 to 750 mm. Most of the precipitation falls during the growing season.
Rainfall is adequate for range grasses but marginal for cultivated crops.
High temperatures and high evaporation and transpiration rates limit crop production. The Nueces River and deep wells provide water for irrigation. Deep wells and ponds provide water for livestock and for domestic use. Most of the soils are Ustalfs. They are deep and moderately coarse textured and coarse textured.