The releases will help provide the depth necessary for river commerce to pass in Thebes, Ill., where rock formations pose a hazard at -5 feet and below, the Corps says. Carlyle Lake is one of few Corps reservoirs able to significantly capture water above its seasonal pool level to support navigation during the current drought.
Releases gradually increased to 4,000 cubic feet per second between Saturday and late Monday. The full extent of the releases is expected to reach Thebes by Dec. 24. The Corps say this will provide an additional six inches of depth in this critical reach of the river.
Releases will continue if needed until the river level increases through precipitation, or until Carlyle Lake reaches its winter pool elevation. With the additional release schedule, Carlyle Lake is expected to reach its winter pool level in approximately three weeks. The Corps says additional releases from other reservoirs will be considered if the need arises.
Maj. Gen John Peabody, Mississippi Valley Division commander, authorized all the lakes on the Upper Mississippi River system to hold an additional 10% above seasonal pool levels in October in anticipation of historic low levels on the Middle Mississippi.
"With the Mississippi River watershed receiving less rain than forecasted, we are working to provide the water depth needed at a time when inches make a difference," Peabody said. "We'll continue to work closely with the navigation industry and our partners in the U.S. Coast Guard to keep the vital artery for commerce open."
On Tuesday, Corps officials met with state and local representatives to discuss the release and river navigation. The meeting was organized by Sen. Dick Durbin, D-Ill., and also attended by Capt. Byron Black of the U.S. Coast Guard, Rep. Jerry Costello, D-Ill., Rep. John Shimkus, R-Ill., and Illinois Lt. Gov. Sheila Simon.
Maj. Gen. Peabody also attended the meeting, noting that removal of limestone began this week, which he expects will ensure that barge restrictions will not be needed at this time.
"We remain cautiously optimistic that if we do have any interruptions, it will be short in duration as we continue to maintain a safe and reliable navigation channel," Peabody said.
Along with work on rock removal, the Corps plans to continue to dredge.
"The Dredge Potter has dredged more than 6 million cubic yards of material on the Upper and Lower Mississippi since it began operations in June," said Army Corps St. Louis District Commander Col. Chris Hall. "We will continue dredging problem areas, conducting channel patrols and surveys to keep commerce safely moving on the Middle Mississippi."