Projections Call For Rapid Fall In River Levels At St. Louis
With the seasonal decrease in flows from the Missouri River, industry attention concerning low-water conditions is turning to the St. Louis, Mo., to Cairo, Ill., reach of the Upper Mississippi.
The Corps of Engineers is forecasting a river stage of –5 feet in St. Louis by December 13, which would put it in the top six lowest river levels on record, said Bernie Heroff, chairman of the River Industry Action Committee (RIAC). The record is –6.2 feet on January 16, 1940. The records for the region go back to the 1860s.
The stage was at –1.3 on November 30, with a small rise expected through December 3 followed by a rapid fall during the next week. Heroff said the Corps of Engineers currently expects the gage could descend to to –5.4 feet by about December 20, barring any major change in weather patterns.
The last time the river fell below –5 feet in St. Louis was in 1989, when it reached –5.32 feet. In contrast, the low in 2022 was –3.09 in October, and this year’s previous low was –3.68 feet on September 10.
Recent rain north of St. Louis was expected to help short-term, but at the same time the seasonal reduction in flow of the Missouri River was beginning to be felt.
Releases from Gavins Point Dam on the upper Missouri were reduced beginning November 22 from 32,000 cubic feet per second (cfs.), stepping down by 3,000 cfs. each day until reaching 15,000 cfs. Releases were then to be paused before stepping down 1,000 cfs. every five days to the winter release rate of 13,000 cfs., said John Remus, chief of the Corps’ Missouri River Management Division.
The flow support season ended on December 1 at the mouth of the Missouri River.
Remus said the Missouri River has been providing a significant amount of the flow from the St. Louis to Cairo reach of the river, although less so south of Cairo because of the influence of the Ohio River as a major tributary.
The Corps of Engineers has no authority to either lengthen the navigation season or to increase flow supports solely to help maintain the Mississippi River, under the Missouri River Project, Remus said.
“We get asked that question every time we have a drought,” he said.
More than a decade ago, Congress passed the Missouri River Authorized Purposes Study, which would have included looking at the river’s other uses, but shortly after the study began it was defunded and deauthorized, he said.
Within its current authority, the Corps of Engineers works closely with industry to try to maintain the system for the benefit of all stakeholders, however, he said.
Heroff said RIAC is involved in weekly calls with the Corps of Engineers, U.S. Coast Guard and other industry groups to continue monitoring the situation.
“They’re constantly surveying the river between St. Louis and Cairo,” he said.
He added that proactive dredging was also taking place. The dredge Potter was working at Upper Mississippi Mile 97 with its next assignment scheduled to be Mile 102.3.
The Goetz planned to work at Mile 171.5 until December 2 with the next assignment planned for Mile 159 for about 10 days before moving to the areas both above and below the Jefferson Barracks Bridge.
The Pathfinder was also working at the lower entrance to the Chain of Rocks Canal.
The Coast Guard also planned to have the buoy tender Chippewa running between Chester, Ill., and Cairo over the next week, Heroff said.
On the Lower Mississippi, the situation had improved, with rain moving downriver providing some temporary relief. Groundings were minimal for now, but the Lower Mississippi was expected to begin falling rapidly beginning around December 7, said Randy Chamness, co-chairman of the Lower Mississippi River Committee (LOMRC).
The dredge Jadwin was en route from Stack Island to Lakeport at Lower Mississippi Mile 525, where dredging was to begin December 1.
The dredge Hurley was still working in the Memphis, Tenn., region, but was set to move December 2 to the Williams/Beckwith area, Miles 925-928.
Chamness said this dredging was proactive in nature.
“Right now there are no issues there, but it’s in preparation for the fall that we pretty much know is coming,” he said.
More rain in the forecast could also help the Lower Mississippi, Chamness said, but he said industry was also hoping for mild weather in the coming weeks as any ice forming on the Illinois or Upper Mississippi could worsen conditions downriver.