U.S. Army Corps of Engineers emergency and water management officials held a call June 13 to communicate to Midwest Congressional representatives, Tribal, state and local government officials (including levee sponsors and emergency managers) an update of current runoff conditions, system storage and a status of flooding response and recovery activities.

A recording of that call can be accessed here: https://www.dvidshub.net/audio/58374/missouri-river-basin-water-management. It is also available via Podcast at: https://podcasts.apple.com/podcast/id508457675.

All of the information provided on this call is accessible through the Missouri Basin “Web App.” The information at the links in the web app is the most up-to-date information from the National Weather Service and the U.S. Army Corps of Engineers. https://go.usa.gov/xmtYU.

Scott Dummer from the Missouri Basin River Forecast Center, National Weather Service, provided an update on Missouri River tributaries throughout the basin that are in major or moderate flood status these rivers are the James and Big Sioux rivers in South Dakota, the North Platte River in Nebraska, the Big Sioux River in Iowa, and the Big Blue and Black Vermillion rivers in Kansas, as well as numerous rivers in Missouri and many points along the Missouri River from Blair, Nebraska to St. Louis, Missouri.

From June 14 to 19, up to 5 inches of rain are forecast to fall over the southern Osage River Basin, in Missouri and over the Osage and Missouri river tributaries in areas downstream of Kansas City.

“With rivers already at elevated levels, this forecast rain will cause small rivers to again rise, some above flood stage, and slow down the recession of the Missouri River,” said Dummer.

The National Weather Service provides official river stage and weather forecasts.  Its website -- www.weather.gov/mbrfc -- provides river observations and forecasts; weather observations and forecasts, and additional information including the spring flood outlook under items of seasonal interest. The Corps’ Missouri River Water Management Division shares all release forecasts with the National Weather Service for incorporation into their forecast products.

The Missouri River Water Management Division provided an update on the June 12, three-week regulation forecast with projected reservoir elevations and release forecasts through early July. The three-week regulation forecast is updated each Wednesday or more frequently if runoff conditions warrant it.

Key points from Mike Swenson, power production team lead for the Missouri River Water Management Division included the Oahe reservoir is forecast to exit the exclusive flood control storage zone on June 15, the Garrison Reservoir has entered its exclusive flood control zone, flows will be increasing from Garrison Dam to a target 46,000 cubic feet per second on June 24, and on June 17, some flows will be transferred to the spillway to accommodate scheduled maintenance at the Garrison project.

John Leighow, chief of Readiness and Contingency Operations, emphasized the Corps commitment to provide recovery support under Public Law 84-99 authorities noting the Omaha and Kansas City district’s aggressive efforts to assess damages, provide initial and temporary repairs, and that work would continue until all repairs are complete.

Leighow noted the President had signed a disaster relief bill that provides funds to support recovery efforts.   

“Our senior leadership is engaging Congressional and State leaders on the subject and we are awaiting additional guidance from the U.S. Army Corps of Engineers Headquarters would be who are actively working this guidance before those funds become available for use,” said Leighow.

The Omaha District provided an update on the status of post flood levee inspections and rehabilitation. They keep this information updated on their website at: https://go.usa.gov/xmtYB.

Noteworthy items from Matt Krajewski, chief of Emergency Management for the Omaha District, included the completion of the initial breach closure at levee L611-614 near Council Bluffs, Iowa; a contract award for initial breach repairs to the L550 levee system near Weston, Missouri;   and pending contract awards for L575 near Percival and Hamburg, Iowa and L594 in Fremont County, Iowa.

Estimated completion dates for work that is already taking place includes L601 near Bartlett, Iowa, June 17; L575-A near Percival, Iowa, June 14; L575-B near Hamburg, Iowa, July 8; and L594 in Fremont County, Iowa, June 14.

Eric Shumate, chief of hydrologic engineering from the Kansas City District provided an update on the status of the reservoirs on the Kansas River and the Osage River. This information is available on their website at: https://go.usa.gov/xmhrd. 

“We still have very little remaining flood control space in the 10 reservoirs located within the lower Kansas basin and Osage River basin, of the little over 9 million acre feet of combined flood storage space in these 10 reservoirs, 83% is occupied. Significant rainfall can push one or more of these reservoirs into surcharge operations,” said Shumate.

The Kansas City District provided an update on the status of their flood response efforts and levee conditions. They keep this information updated on their website at: https://go.usa.gov/xmtYD.

Jud Kneuvean, chief of Emergency Management for the Kansas City District, advised that the U.S. Coast Guard would be re-opening the river to navigation. The district is expecting to receive up to 90 additional requests for assistance from levee sponsors affected by flooding resulting from the May rainstorm.

A question and answer session followed with many questions related to the forecast rain in Missouri.

To address questions we have been receiving about different levee categorizations and their repairs, we prepared a graphic depicting levee vocabulary.

Finally, though not provided on the call, the Missouri River Water Management Division is providing further clarification regarding the release rate of 75,000 cfs from Gavins Point Dam.

Releases from Gavins Point Dam are high because releases from any of the other five Missouri River Mainstem dams eventually comes through Gavins Point.

In April and May, late plains snow, saturated soils, and record rainfall caused record high runoff that entered System reservoirs in South Dakota. At the same time, releases from Garrison Dam, which flows into Oahe, were cut in half. Despite reducing Garrison’s releases, the runoff caused the Oahe and Fort Randall reservoirs to rise into their exclusive flood control zones. As the pools rose, higher releases were necessary to reduce the chances for even higher releases.

These releases eventually flow into and are released from Gavins Point. Because of the limited storage space at Gavins Point, average inflows and releases are usually about the same.

Through maintaining the 75,000 cfs system release, reservoir levels at Oahe and Fort Randall are slowly receding. The Oahe reservoir is forecast to exit the exclusive flood control zone on June 15 and Fort Randall is forecast to exit the exclusive flood control zone on June 20.  

The total amount of water stored in the system and the forecast runoff for the rest of the year are how release rates are projected. More runoff requires higher releases. When, where and how much rain falls influences release amounts and where they occur. 

A mid-month runoff forecast update is expected next week.