Alluvial deposits in the Red River Valley constitute a relatively undeveloped but potentially important aquifer in northwestern Louisiana. The alluvium is 75 to 150 feet thick in the thalweg of the entrenched valley. It consists of clay, silt, sand, and gravel; the sand and gravel constitute the lower half of the deposits.

The Red River alluvial aquifer is a relatively undeveloped source of large amounts of freshwater int he pool 2 area of the Red River waterway navigation project in Louisiana. Infiltration of rainfall provides the primary source of recharge to the alluvial aquifer. In general, ground-water levels are highest during December through May, when most of the rainfall occurs and evapotranspiration is low. Ground-water levels are lowest during September and October, when the least rainfall occurs and evapotranspiration is high. Water levels in the alluvial aquifer typically fluctuate 10 feet or less. However, these fluctuations can be much larger in wells near the river. The Red River is hydraulically connected to the alluvial aquifer, and ground-water levels near the river fluctuate in response to changes in river stage.

Rapides Parish in central Louisiana possess abundant water resources. Ground water furnishes nearly all water supplies, but the resource has been developed to only a slight extent. Surface water is used little for domestic or industrial supplies but its use for irrigation is increasing.