Weekend rains push Patoka Lake levels

Patoka Lake photo courtesy U.S. Army Corps of Engineers


PATOKA LAKE — Weekend rains pushed levels at Patoka Lake to 547.48 feet, or about 96 percent of the dam’s capacity. It’s still too early to tell if the structure will reach capacity with rain in the forecast later this week, but even if it does, a major overflow is not predicted.

“Basically, if we just touch spillway crest, nobody is gonna see any difference,” Jamie Blanton, a hydraulic engineer with the Louisville U.S. Army Corps of Engineers, said today in a phone interview. “It’s gotta get quite a bit of water over the spillway before anything’s gonna look different than what people are used to. So, at this time, we’re not expecting that.”

A Friday afternoon press release from the Corps explained that if emergency spillway flow occurs due to an additional heavy rainfall event, residents in Dubois, Jasper and other areas downstream would experience higher river stages than they would with a similar rain event due to the fact that the dam has reached its maximum amount of flood storage.

That release went on to say that staff have been performing increased surveillance and monitoring of the dam to ensure its safety, and no concerns of the integrity of the dam have been observed. It is structurally sound and operating as designed.

Rainfall amounts are being monitored and staff are increasing the pumping according to plan. Blanton explained that today, water is being pushed out of the lake at 1,200 cubic feet per second — a pretty fast rate.

“We’re trying to push it as hard as we can without causing any problems downstream,” Blanton said.

Last week, representatives from the cities of Jasper and Huntingburg as well as Dubois County met to discuss the situation with lake management, and ultimately, local stakeholders voiced their support to aggressively release water through May 15 to help drain the dam.

A previous request to release extra water from the lake to preemptively cut the water level was approved in early March, but the more than 17 inches of rain that have fallen in the roughly two months since have complicated efforts to drain the lake down to a normal level. It currently rests a little more than 11 feet higher than it normally is at this time of the year.

“It’s really not even so much what’s happening on the lake that’s a factor, it’s what’s happening on the gauges downstream,” Greg Carpenter, the U.S. Army Corps of Engineers’ natural resources project manager at Patoka Lake, explained Friday. “So, we’ll put as much in that channel as we can without causing significant damage.”

It takes about 24 hours for the flow from the dam to reach Jasper, and if water is being pumped out at a high rate before a rain event, river flooding can be exacerbated.

Carpenter said that “the dam is operating as it should and everything’s working very well,” adding that “this is what we prepare for.” He said the lake’s primary function is to reduce flooding and damage downstream, and as of Friday, it was doing just that.

The spillway overflowed in May 2011 in an event that led to widespread flooding in the area. During that event, the dam swelled to around 125% of its capacity.

Lake management is currently keeping a close eye on the water levels.

“I would like them to know that this is what the Army Corps of Engineers does and this is what we prepare for,” Carpenter said in a message to readers. “You see us working out at the lake and running around the dam and maintaining facilities. It’s all in preparation for this event.”

More on DuboisCountyHerald.com