Reservoir officials again increasing discharge from lake

RANKIN CO., Miss. (WLBT) - For the third time this week, the Pearl River Valley Water Supply District is increasing the amount of water being released at the Spillway.

The agency that governs the Barnett Reservoir announced the decision Friday morning, saying that the discharge would be increased to 55,000 CFS or cubic feet per second.

The additional discharge is needed to help lower the lake to 297 feet above sea level. It currently sits at 298.13 feet, due to the increased runoff caused by heavy precipitation upstream.

“Not to be redundant, but everybody knows it rained a lot,” said PRV General Manager John Sigman said at a Friday press conference. " It rained a lot in Carthage and Walnut Grove - 12 inches - all that water comes to the reservoir... what comes in has to go out we can retain very little water.”

The reservoir sits on the Pearl River, and water flows into it from upstream. Water is released downstream along the Spillway.

PRV officials say the amount of water being let out could be increased again in the next several days, especially as more runoff comes in.

“What we’re doing now is letting a little more out and what’s coming in in order to attenuate the peak that’s going to hit us on Monday night, Tuesday morning,” he said. " That peak is estimated at this time to be 67 to 72,000 gallons, cubic feet per second. That’s a lot of water.”

That increase in outflow, coupled with the latest heavy rains, is causing the Pearl to swell. National Weather Service expects the river south of the reservoir to rise to 36 feet, eight feet above flood stage.

At that level, homes across the capital city will be impacted. The flooding also will impact a mobile home community in Ridgeland, which Mayor Gene McGee was asking people to begin evacuating Friday morning.

Sigman said PRV will hold back as much water as possible, as long as possible, but said the reservoir does not have as much capacity as it did in 2020.

In early 2020, heavy rains caused severe flooding in the metro, impacting about 500 structures in Northeast Jackson.

“In 2020, we did have a lot of extra capacity because lake [level] was down to battle of giant Salvinia, which by the way we eliminated. However, this time, we didn’t have that we had a little bit of room. But then, the amount of direct rainfall that fell on the lake took that up immediately,” Sigman explained. “So, we’re having to release more and more water... We have to do that because the lake is continuing to rise.”

Sigman says if the reservoir rises to 300 feet, the dam along the Spillway is designed to fail, something that would release even more water downstream.

“Contrary to popular belief, we don’t have a way to activate that with a switch or with dynamite or anything like that itself erodes and then you’re suddenly putting 10 feet of water from the lake, down river,” he said. “And that’s an uncontrolled situation that we don’t want to face.”

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