Lake Chicot NAM-19

Lat.33.322 Lng.-91.278 Alt.31.5
Riparian Nation(s) USA
Surface Area 17 km2 Mean Depth 3.63 m Volume 0.06 km3
Shoreline 58.2 km Catchment Area 906 km2 Residence Time 0.4 yr
Frozen Period None Mixing Type Polymictic Morphogenesis/Dam
Related Info/Site

Description

Lake Chicot is an oxbow lake that was created more than 600 years ago by the meandering of the Mississippi River. It is located in Chicot County in southeastern Arkansas adjacent to the present Mississippi River. As the largest natural lake in Arkansas, it earned an early reputation for its good fishing and recreational value.

A flood in 1927 partially created a natural earth dam dividing the lake into a large lower lake and a considerably smaller upper lake. This dam was completed by the State of Arkansas. Development of a levee system forced the enlargement of the lake's watershed to its present 350 square miles.

Initially this alteration affected only the volume flow through the lake, drastically reducing the water residence time. Because the watershed was located in one of the most agriculturally productive regions in the world, the land, predominantly comprised of clay and fine silts, quickly became more intensively farmed. The use of agricultural chemicals increased, large amounts of sediments were produced and the lake began to become severely impacted by this activity.

In the early 1960's Congress enacted legislation authorizing the Corps of Engineers to begin planning a method of restoring the lake. Plans were made to construct three structures; a dam to prevent poor quality water from entering the lake, a combination gravity flow-pump facility to divert the poor quality water through the levee into the Mississippi River, and a dam on the outflow to regulate lake levels and regulate discharge. The structures were placed into operation during March 1985 and are operational according to a plan to improve the water quality in the lake. These structures and plans have resulted in a nearly complete restoration of the lake (Q).

Photo of Lake Chicot
Photo: B. Morrison