Along the north and eastern county boundary, the Red River Bottomlands follows the Red River. This eco-region contains floodplains, low terraces, oxbow lakes, meander scars, backswamps, natural levees, and the meandering Red River. Natural vegetation is southern floodplain forest unlike the oak–hickory– pine forest of higher, better drained compared to adjacent forests. However, the region has widely been cleared and drained for agriculture. The Red River is almost continuously turbid; suspended sediment concentrations are usually much higher than in the Saline River or Ouachita River due to land cover, land use, and upstream lithology differences.