VICKSBURG, Miss. – U.S. Army Corps of Engineers (USACE) Vicksburg District will begin a slow three foot draw down on the Ouachita River above the Columbia Lock and Dam over the weekend. The lowering of the pool is necessary due to the ongoing non-breach emergency at the lock and dam.
The Columbia pool draw down is being triggered by decreasing flows on the Ouachita River. This draw down will lower pool levels around to where they were in Fall 2024. The pool has recently been back at normal or high levels due to heavy rain and high river flows this Spring. This lowering of the pool will result in lower river levels throughout the pool from Columbia Lock and Dam up to Felsenthal Lock and Dam and will affect river levels around Monroe, LA. The pool at Jonesville Lock and Dam is not being raised at this time. However, it is expected to be raised in upcoming months.
Currently, no boat ramps are closed and no ramp closures are expected over the Fourth of July weekend. Use caution while using ramps as there is sand deposition from the recent high water. Boat ramps do not start seeing impacts until the Columbia Lock and Dam upper gage is at 49 ft. As of July 3, it was at 52.1 ft. USACE will be working to clear sand and keep ramps open as the pool is lowered.
The change in normal pool levels is in response to an ongoing non-breach emergency declaration by the Vicksburg District. The purpose of the pool change is to reduce risk until repairs can be made to address concerns that were discovered at the Columbia Lock and Dam in August 2024.
Lowering the Columbia pool decreases pressures at the structure by decreasing the difference between the water level on the upstream and downstream sides of the dam. The difference in water levels at Columbia is currently being limited to 13 feet. The biggest difference in water levels occurs during low flow. During high flows on the river, the river levels on the upstream and downstream sides of the dam equalize, reducing pressures at the dam. During low flow, the difference in river levels at the dam increases, which in turn, increases pressures at the dam. Lowering the Columbia pool during low flow helps to reduce that differential and lowers risk.
During periods of low flow, the Jonesville Lock and Dam pool, which is downstream from Columbia Lock and Dam, can be raised up to 2 feet to further reduce the differential at Columbia. Raising the pool at Jonesville only has a significant impact on the downstream water level at Columbia Lock and Dam when the pool is relatively flat, which occurs when river flows are low. When the pool is flat, raising the pool at Jonesville by 2 feet also results in an increase of about 2 feet in water levels on the downstream side of Columbia. Current flow conditions on the river prohibit a raise at Jonesville from having a significant impact at Columbia. The Jonesville Lock and Dam Pool is expected to be raised in upcoming months as flows decrease further.
For current conditions on the Ouachita River:
USACE MVK Water Management – Ouachita River Report: https://wm.mvk.ds.usace.army.mil/ouachita.htm
Ouachita River Navigation Current Pool Levels Graphic: https://wm.mvk.ds.usace.army.mil/plots/ouachita_structures.png
The USACE Vicksburg District is engineering solutions to the nation’s toughest challenges. The Vicksburg District encompasses a 68,000-square-mile area across portions of Mississippi, Arkansas, and Louisiana, that holds nine major river basins and incorporates approximately 460 miles of mainline Mississippi River levees. The Vicksburg District is engaged in hundreds of projects and employs approximately 1,100 personnel.
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