Watershed
The Red River's watershed covers 65,590 square miles (169,900 km2) and is the southernmost major right tributary of the Mississippi, and the southernmost major river system in the Great Plains. Its drainage basin is mostly in the states of Texas and Oklahoma, but also covers parts of Arkansas and Louisiana. Its basin is characterized by flat, fertile agricultural land, with only a few major cities. The drainage basin of the Red River is very arid and receives little precipitation. As a result, much of the river above the Texas-Oklahoma border is intermittent, and until the river is past its great bend south in Arkansas, the flow varies widely. Most of the agriculture in the basin is sustained by groundwater, which is rapidly being depleted. The lower course of the river flows through a series of marshes and swamps, where its flow is dramatically moderated.
Read more about this topic: Red River Of The South