LDWF schedules Lake Bistineau drawdown

MINDEN, La. -- The Louisiana Department of Wildlife and Fisheries will begin lowering the water level at Lake Bistineau on Aug. 12 in an effort to slow the spread of the invasive aquatic plant giant salvinia.

The annual drawdown will affect the lake in Webster, Bossier and Bienville parishes. LDWF said the action is necessary despite months of intensive vegetation management that allowed the lake to remain at its normal level longer than usual this summer.

Once the water control structure is opened, the lake is expected to drop between 4 and 6 inches per day until it reaches a maximum of 8 feet below normal pool stage. The exact rate will depend on rainfall in the watershed.

The drawdown is scheduled to continue until around Nov. 30, when the structure will be closed to allow the lake to refill in time for winter and early spring recreational activities.

LDWF said exposing stranded giant salvinia to late-summer heat will help kill the invasive plant as it dries on the lakebed. Herbicide applications will continue during the drawdown in areas that do not completely dewater, and floating booms may be installed to trap vegetation where it can dry out.

Even with the drawdown, officials estimate about 10,000 acres of water will remain in the lake.

Boaters will still be able to launch from the Port of Bistineau Launch, Bossier Public Launch, Grice's and the Bayou Dorcheat Public Launch. However, LDWF is urging boaters to use extra caution because low water levels may expose underwater hazards, and floating booms will be present in some areas. Markers may identify the safest locations to cross the booms.

The drawdown is part of LDWF's long-term management plan to control excessive aquatic vegetation, maintain recreational access and improve fish habitat.

According to the agency, crews and contractors have treated about 4,900 acres of aquatic vegetation during roughly 120 days of herbicide applications this growing season at a cost of about $514,000. In addition, LDWF staff have released more than 37,000 giant salvinia weevils into hard-to-reach areas of the lake to help control the invasive plant biologically.

Officials said those efforts, combined with favorable weather conditions, allowed Lake Bistineau to remain at full pool longer this year before the drawdown became necessary.