Gulf Coast Rivers of the Southwestern United States

The Gulf Coast rivers of the southwestern United States encompass a region defined by strong temperature and precipitation gradients. The western rivers of the Pecos and Devils flow through landscapes dominated by shrub/scrub with some isolated, montane forests in the upper Pecos region. The easternmost three rivers include the Trinity, San Jacinto, and Neches. The eastern rivers also contain large urban areas including the Dallas-Fort Worth and Houston metropolitan areas. The central rivers include the San Marcos and Nueces rivers. Both are spring dominated from the Edwards Aquifer. The San Marcos supports a unique ecosystem of many endangered and endemic species in central Texas. The Nueces River and its tributaries provide a beautiful range of canyonlands within its upstream Edwards Plateau ecological region and then flow to the flat, Coastal Plains along the Gulf of Mexico. The Nueces-Rio Grande basin includes small creeks (arroyos) and a southern section dominated by the Rio Grande delta and its ancient distributaries called resacas.