Entergy: Drawdown five feet this year

The annual wintertime drawdown on lakes Hamilton and Catherine will be 5 feet this year, Entergy Arkansas Inc.’s Hydro Operations office said Thursday.

“Last week, Entergy Hydro performed our annual vegetation inspection with the Arkansas Game and Fish Commission. Even though less vegetation was found to be present at our check sites, due to last year’s mild winter, and some projects on the lake, it has been determined that we will have a 5-foot drawdown on both lakes Hamilton and Catherine,” Kimberly Bogart, lakes and property coordinator for Entergy Arkansas Inc. Hydro Operations, said Thursday in an email.

The drawdown will begin Nov. 1. The

lakes’ levels will be drawn down around 6 inches a day until Nov. 10, when they should reach the winter lake levels of 394.7 feet above mean sea level on Lake Hamilton and 299 feet msl on Lake Catherine, Bogart said.

The depth of the drawdown varies each winter, in part, to curb the growth of nuisance vegetation. A vegetation management plan developed in conjunction with the AGFC usually calls for alternating 3-foot and 5-foot drawdowns.

The reasoning behind varying the depth is to keep certain plant species from getting accustomed to a constant lake level. Other factors include water clarity, since reduced visibility can decrease the amount of sunlight that can reach the bottom of the lake’s shallow areas, and the severity of the winter.

The drawdown was 3 feet in 2014-15 and 5 feet in 2015-16.

It isn’t unprecedented for Entergy to do 5-foot drawdowns twice in a row, utility officials said last year, and there was an 8-foot drawdown on Lake Catherine one year to allow for a dam inspection.

“Please note that if we get a significant rainfall during this time period, it may affect the dates and amount of water released,” Bogart said.

“Moving forward, Entergy Hydro anticipates using Nov. 1 through Nov. 10 as the annual drawdown period,” she said.