The U.S. Army Corps of Engineers St. Louis District reports that on Dec. 15 it began increasing releases from Carlyle Lake in support of safe navigation on the Mississippi River.
Water from the lake will help provide the depth necessary for river commerce to pass Thebes, Ill., where rock formations pose a risk to navigation at -5 feet and below on the St. Louis gage. Carlyle Lake is located on the Kaskaskia River system in Southwest Illinois.
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. Maj. Gen John Peabody, Mississippi Valley Division commander, authorized all the lakes on the Upper Mississippi River system to hold an additional 10 percent above seasonal pool levels October 17 in anticipation of historic low levels on the Middle Mississippi.
Releases from Carlyle Lake began late Saturday, and will increase gradually to 4,000 cubic feet per second by Monday afternoon. The full extent of the releases is expected to reach Thebes by Dec. 24. 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
"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 Dec. 14, the Corps announced the schedule for removing rock formations in the Mississippi River near Thebes, Ill. The agency has awarded two contracts for rock removal work in a nearly six mile stretch of river. Newt Marine Inc., of Dubuque, Iowa, will remove the rock formation upstream of Thebes; Kokosing Construction, from Fredericktown, Ohio, will remove the rock formation downstream of Thebes.
Work began Saturday, Dec. 15, upstream of the Thebes railroad bridge. While final blasting plans are still being developed, full operations will begin early the week of Dec 17, with blasting to take place during daylight hours. The U.S. Coast Guard is coordinating notices to mariners, and river closures are scheduled for 16 hours on working days starting Monday, Dec. 17, between 6 a.m. and 10 p.m. each day during the rock removal, with traffic allowed to pass for eight hours.
The work will remove around 890 cubic yards of limestone from the water-starved river to reduce the risk for vessels in the channel during low water. The rocks are part of a large formation that impedes the navigation channel during low water. More rock removal is planned for later dates, but the work that began Saturday will address areas that will have the most immediate impact on the navigation.
Removing the rock formations are one of many operations the Corps and U.S. Coast Guard are undertaking along the narrowing river to maintain a 9-foot deep channel for river navigation. Dredging has been ongoing since early July to preserve the channel, as well as continued surveys, channel patrols to keep commerce safely moving on the Middle Mississippi.
"The drought across much of the Midwest is making river navigation challenging," said Col. Chris Hall, St. Louis District commander. "We are taking additional measures and are confident that we will be able to maintain a safe and reliable channel for our partners in the river industry."