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)

The Big Sandy River lies entirely within the State of Kentucky; however, the total watershed area of 4,283 square miles also drains portions of Virginia and West Virginia. Of the nearly 4,483 square miles that make up the basin, 54% is located in Kentucky, 23% is in West Virginia, and 23% is within Virginia. Big Sandy River is formed by the junction of Tug and Levisa Forks at Louisa, Kentucky, and flows in a general northerly direction for 26.83 miles to its junction with the Ohio River at Kenova, West Virginia and Catlettsburg, Kentucky. The river, along its entire length, forms a part of the boundary between the states of Kentucky and West Virginia. Levisa Fork and Tug Fork are the two largest tributaries of the Big Sandy River Basin draining 2325 and 1559 square miles, respectively, of the total basin. The Big Sandy Basin is irregular in shape, having a length of about 105 miles and a maximum east-west width of 91 miles.

The Big Sandy River Basin lies wholly within the physiographic province known as the Appalachian Plateau. The topography of the Big Sandy River watershed is generally rugged. The area is well dissected and has a total relief of about 3,300 feet. Over most of the area the main streams and their many tributaries flow in deep, narrow, sinuous valleys between steep-sided ridges. In the headwater regions the terrain is mountainous, whereas in the lower portion of the area the valleys are relatively wide and the hills are gentle and rounded, averaging about 300 feet in height.

The Big Sandy River Basin contains a wide variety of flooding problems ranging from flash floods in the upper portions of the basin; major community flood damage centers such as Williamson, Matewan, Pikeville, Prestonsburg, and Paintsville; and backwater flooding from the Ohio River in the lower portion of the basin. Basin runoff is highest during the winter months when storm rainfall may combine with snowmelt and when frozen or saturated ground can result in very low infiltration rates. Runoff is lowest during late summer and early fall when the ground is dry and infiltration losses are high. However, precipitation during these seasons may be quite heavy and of sufficient intensity to more than make up for the higher infiltration rates.

There are no large cities in the Big Sandy River Basin, and the rural areas are sparsely settled. The largest city in the basin is Pikeville, KY, one of only 8 cities in the basin with a population exceeding 3,000 people.

Four cities are protected by USACE local protection projects in the basin, they are Matewan, WV, Williamson, WV, Pikeville, KY, and Prestonburg, KY. The Big Sandy River is the only navigable waterway, used for the local coal industry as well as an oil refinery located on the river.