The Corps Water Management System (CWMS) includes four interrelated models to assist with water management for the basin:

- GeoHMS (Geospatial Hydrologic Modeling Extension)
- ResSIM (Reservoir System Simulation)
- RAS (River Analysis System)
- FIA (Flood Impact Analysis)

Little River rises in the mountainous country of Le Flore County in southeast Oklahoma and is about 217 miles long. It flows in a westerly direction from its source through Le Flore and Pushmataha Counties, Oklahoma, to the McCurtain County line, thence easterly through McCurtain County, Oklahoma, and Sevier County, Arkansas, to a point near Horatio, Arkansas, then it turns southeast to join the Red River near Fulton, Arkansas. The drainage basin is fan-shaped, with a total area of about 4,260 square miles. Five large tributaries join Little River from the north. They are: Glover Creek, drainage area 338 square miles, entering 127.9 miles above the mouth; Mountain Fork River (Broken Bow Lake), drainage area 842 square miles, entering 87.1 miles above the mouth; Rolling Fork River (DeQueen Lake), drainage area 354 square miles, entering 72.9 miles above the mouth; Cossatot River (Gillham Lake), drainage area 530 square miles, entering 43.5 miles above the mouth; and the Saline River (Dierks Lake), drainage area 552 square miles, entering 22.8 miles above themouth. These streams are left bank tributaries, Each of these tributaries and the head waters of Little River flow out of the mountainous area in southeast Oklahoma and southwest Arkansas to the main Little River bottoms, paralleling the Red River in southern Oklahoma and southwestern Arkansas. Nearly 75 percent of the total drainage area is mountainous country covered with a heavy growth of timber. The remaining 25 percent of the drainage area is timbered overflow area and rolling hill country. The elevation of the headwaters of Little River and its tributaries is in excess of 1,000 feet msl. The elevation of the land at the mouth of Little River near Fulton, Arkansas, is about 235 feet msl. There is considerable overflow area on Little River and in the lower reach of each of the five main tributaries. The channel slope varies