Drawdown of Henderson Lake in Atchafalaya Basin Postponed Until September 1

Do you remember last year driving over the Atchafalaya Basin Bridge and seeing little to no water over much of the swamp? Many of us do and boy was it eery.

The reason for that was a drawdown of the lake. That was supposed to happen again soon but now it's been pushed back a few more weeks.

The Louisiana Department of Wildlife and Fisheries (LDWF) originally announced that a scheduled drawdown of Henderson Lake in St. Martin Parish would begin on August 1, 2023.

However, that now has been delayed to start on September 1, 2023, and run through November 30, 2023.

The delay in the drawdown is due to a formal request from the Coastal Protection and Restoration Authority (CPRA) to the St. Martin Parish Government. This request was based upon the current implementation of the Henderson Lake Dixie Pipeline Spoil Bank Hydrologic Restoration Project.

CPRA said that if the drawdown began at the original start date, water elevation would drop to a level where the marsh buggy excavators could not cross the Enterprise Pipeline, and construction of the Henderson Lake Dixie Pipeline Spoil Bank Hydrologic Restoration Project would have to be suspended. Therefore, all parties involved agreed to postpone the drawdown.

What is the importance of the drawdown?

This long-standing collaboration between LDWF and the St. Martin Parish Government helps manage aquatic vegetation and improve fisheries habitat.

One of the main aquatic vegetation that needs to be managed is hydrilla. Those plants regerminate in September and October, so the drawdown comes at a perfect time to help eradicate this species of aquatic vegetation.

Additionally, the drawdown will help out the lake's fish population by promoting a "balanced predator-prey relationship," where forage fish are more available to predator species.

The dewatering will also improve the spawning habitat by promoting the decomposition and dying of organic materials such as leaf litter and submerged vegetation.

The southern control structure gates will open on September 1 and will close back up on November 30.

The lake will dewater at a rate of two to four inches per day until it reaches three feet below pool stage. However, the dewatering rate could be impacted by local rainfall in the surrounding watershed.

When the drawdown gates close up on November 30, this will allow the lake to be refilled.

Houseboat owners on Henderson Lake are encouraged to take any necessary precautions as soon as possible.

The LDWF had this to say to houseboat owners:

During the drawdown, boaters will be able to access the lake from the private ramps along the southern levee. Boaters should use caution as numerous obstructions will be exposed or may be present just under the water’s surface.  Boaters should also be cautious about potential interactions with silver carp as the lower water levels are conducive to those fish jumping around moving boats.

You can view the complete Henderson Lake Waterbody Management Plan here: www.wlf.louisiana.gov/resources/category/freshwater-inland-fish/inland-waterbody-management-plans.