HENDERSON, La. (KLFY) — After months of delays, the drawdown of Henderson Lake in St. Martin Parish has begun.
Based on recommendations from biologists with the Louisiana Department of Wildlife and Fisheries, officials with St. Martin Parish Government opened the control gates at the Henderson Control Structure Monday morning to begin lowering the level of the lake.
Shortly after 8 a.m. Monday, Bridge Tender “Snap” Laviolette with St. Martin Parish Government opened the control gates about 10 feet to allow water to flow from the Pontoon Bridge Canal through the control structure into a channel that feeds the Atchafalaya River.
The goal is to lower the lake’s water level by about 3 inches per day until it reaches a target depth of six feet, explained Wes Dupuis with St. Martin Parish Public Works. Once that level is reached, the gates will be adjusted to hold the water level at about 6 feet until Nov. 1, when the water level will be allowed to naturally refill.
At the time the gates were opened, the water level for Henderson Lake was 8.49 feet and the Atchafalaya River was at 2.5 feet.
Originally scheduled to start August 1, the drawdown was delayed due to a request from the Coastal Protection and Restoration Authority (CPRA) to St. Martin Parish Government, based upon the implementation of the Henderson Lake Dixie Pipeline Spoil Bank Hydrologic Restoration Project. That project has been completed.
Dupuis said the parish does a drawdown each year based on recommendations from LDWF biologists to improve the ecosystem, which in turn leads to healthier fish and wildlife throughout the 5,000-acre Henderson Lake area.
LDWF Biologist Manager Brac Salyers said the area is very shallow. As a result, maintaining proper oxygen levels is a challenge. Also, since sunlight can get to the bottom of the lake, vegetation can get out of control.
“Most people think of Henderson Lake as a lake. It’s not. It’s a swamp impoundment,” Salyers said.
Salyers noted there are numerous benefits from conducting an annual drawdown. First, he said decreasing the water level makes it easier for predator fish to be able to catch their prey.
“This helps the predator fish get in better body condition for the spring spawning season,” Salyers said.
Next, he said lowering the water level will result in portions of the lakebed to be exposed, allowing the sun to dry the soil.
“The exposed lake bottom will dry and crack. This allows the soil to harden and compact,” Salyers said. “Next spring, that hard substrate will be very important for bass and bream and other fish to build their nests.”
In addition to the natural benefits, there is also a financial benefit.
“This is free,” Salyers noted. “It doesn’t cost anything to open the control structure to lower the water level. Pesticides are expensive. There is significant savings to the budget to do drawdowns.”