Above-Average Runoff Expected Again In Missouri River Basin
The 2019 runoff forecast in the Missouri River Basin above Sioux City, Iowa, is 28.4 million acre feet, 112 percent of normal, according to the Corps of Engineers’ Missouri River Water Management Division.
“The forecast increased about 10 percent from last month due to the continued accumulation of mountain and plains snowpack in the upper basin,” said John Remus, chief of the division, in a March 7 statement. “Gavins Point releases will be increased from 18,000 cubic feet per second (cfs.) to 20,000 cfs. this week,”
As of March 1, the mountain snowpack was 108 percent of average in the reach above Fort Peck and 103 percent of average in the reach from Fort Peck to Garrison. The mountain snowpack increased during February as a result of colder-than-normal temperatures and above-normal precipitation. Normally, the mountain snowpack peaks in mid-April.
Plains snowpack is currently heaviest in central and eastern North Dakota and north central and eastern South Dakota. The snowpack’s liquid content, or snow water equivalency (SWE), ranges from 2 to 5 inches. The rest of the upper basin has accumulated 1 to 3 inches of SWE while the lower basin ranges from 0 to 2 inches of SWE. The Corps is cooperating with other agencies to acquire plains snow measurements in the upper basin.
Beginning in mid-March, releases from Gavins Point Dam will be adjusted to provide flow support for Missouri River navigation.
Current studies indicate that flow support will be at the full service level for the first half of the 2019 season, which begins on April 1 at the mouth. The actual service level will be based on the total volume of water stored in the system on March 15, in accordance with the guidelines in the Corps’ Missouri River Master Manual.
Flow support for the second half of the navigation season, as well as navigation season length, will be based on the actual July 1 system storage.
Flow support is generally sufficient to provide a 9-foot-deep by 300-foot-wide channel.
Spring Public Meetings
Six public meetings will be conducted throughout the basin April 9–11. The purpose of these meetings is to update the region on current hydrologic conditions and the planned operation of the mainstem reservoir system during the coming months. Meeting times and locations are as follows (all times local):
• April 9, 11 a.m.—Fort Peck, Mont.,
Fort Peck Interpretative Center, Lower Yellowstone Road;
• April 9, 6 p.m.—Bismarck, N.D.,
Bismarck State College, National Energy Center of Excellence (NECE), Bldg. 15, Room 335, 1200 Schafer St.;
• April 10, 10 a.m.—Fort Pierre, S.D., Casey Tibbs Conference Center, 210 Verendrye Drive;
• April 10, 4 p.m.—Sioux City, Iowa, Lewis & Clark Interpretive Center, Betty Strong Encounter Center, 900 Larsen Park Road;
• April 11, 11 a.m.—Smithville, MO., Jerry Litton Visitor Center, 16311 DD Highway; and
• April 11, 4 p.m.—Nebraska City, Neb.,
Lewis and Clark Interpretive Center, 100 Valmont Drive.