Rains bring Patoka levels closer to spillway

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


PATOKA LAKE — Heavy pockets of rain continued to dampen Dubois County this morning, as water levels at Patoka Lake climbed closer and closer to the structure’s spillway.

On Monday afternoon, the dam reached 547.4 feet — or 94% full. The spillway crest elevation sits at 548 feet, and the recent hard and intermittent rainfall pushed the level to 547.78 this morning.

“The potential for water to flow through the spillway will exist from Tuesday, June 18 into the following week,” reads a Monday press release from the Louisville District of the U.S. Army Corps of Engineers. “With current forecasts, the amount of water to be released through the spillway is anticipated to be minor.”

Per the project’s water control plan, the U.S. Army Corps of Engineers has reduced flows from the reservoir down to the minimum 20 cubic feet per second to minimize flood damages downstream. As soon as river flows below the project recede, the Corps will increase releases through the dam’s gated outlet works to begin lowering the lake level.

County soybean and corn farmers have struggled to plant and grow their crops all season, and should the spillway overflow, fields that stand nearby the dam and are already underwater will be further affected.

“A lot of those fields are already in low-lying areas,” said Ken Eck, Purdue Extension-Dubois County educator for agriculture and natural resources. “They’re really saturated. A lot of them are already underwater, in some cases. What will happen is, if they’re not underwater, they will be underwater definitely, and it could be several days to a week, or more, at least.”

That’s if the rain stops. The National Weather Service is predicting a chance of rain in Dubois each day through Thursday, and the possibility for showers and thunderstorms will return again this weekend and early next week. That means many of those crops could be lost.

Patoka Lake reached an extended, elevated stage due to heavy rainfall over the past several months. Efforts to lower the lake level have been hampered by continued rainfall.

In early May, representatives from the cities of Jasper and Huntingburg as well as Dubois County met to discuss the then-rising levels with lake management. Ultimately, local stakeholders voiced their support to aggressively release water through the middle of the month 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 more than 17 inches of rain fell in the roughly two months between the dates, complicating that plan.

As of this morning, 27 county roads were closed due to flooding.

If water does discharge over the top of the emergency spillway at Patoka, the county highway department would close at least one more: Cuzco Road South, which is in the vicinity of the spillway.

“Depending on how much water comes over, it could go over the top of that roadway as well,” said County Highway Supervisor Steve Berg said. “So, we want to be sure that we have it closed and blocked off to where nobody can get through there.”

It should be noted that the spillway is a non-gated, open rock cut located away from the dam. It is designed to allow a safe release of excess water. The top of the dam stands at 564 feet, which is 16 feet above the spillway floor elevation.

“USACE staff have been performing increased surveillance and monitoring of the dam to ensure its safety,” the Army Corps Press Release reads. “No concerns of the integrity of the dam have been observed and it is structurally sound and operating as designed. The lake is currently storing water and providing flood damage reduction.”

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