News Releases

Corps communicating with officials; making system adjustments as plains snowmelt continues

Northwestern Division
Published March 29, 2019
System storage is 60.9 MAF; 4.8 MAF of the 16.3 MAF of flood control storage is occupied. Over 70% of the flood control storage is available to store runoff this spring and summer.
The remaining plains snowmelt in the upper basin has started melting, resulting in large inflows into the System reservoirs (click here). Snowmelt and large inflows are expected to continue over the next week.
Soils in the upper basin have begun to thaw, but still have a lot of frost left (upper right graphic).
Mountain snowpack is about average (bottom right graphic).

System storage is 60.9 MAF; 4.8 MAF of the 16.3 MAF of flood control storage is occupied. Over 70% of the flood control storage is available to store runoff this spring and summer. The remaining plains snowmelt in the upper basin has started melting, resulting in large inflows into the System reservoirs (click here). Snowmelt and large inflows are expected to continue over the next week. Soils in the upper basin have begun to thaw, but still have a lot of frost left (upper right graphic). Mountain snowpack is about average (bottom right graphic).

Today, Brig. Gen Peter Helmlinger, commander of the Northwestern Division addressed participants on a regularly held call that provides updates to Congressional, State, Tribal, local officials and the media.

These calls have been held daily since March 14 when a “bomb cyclone” caused widespread and devastating tributary flooding that created massive inflows into the Missouri River downstream of more than 99 percent of the storage capacity of the Missouri River system of main stem dams.

“We [the Corps] work side by side with the National Weather Service, not just during runoff events but year round to monitor conditions and provide forecasts that are timely and accurate.

I want to thank every Corps' employee who has answered the call to fight the flooding and every volunteer who has acted to assist those who have been affected by the flooding.

I will be meeting with several elected officials next week and am sure that this spring's flooding will be a topic of conversation.

I want to reiterate that the Corps' number one priority in its operations is life and safety. Our focus is to protect life, and mitigate risks from flood events.

The Corps immediate focus over the coming weeks and months is to work with the region’s levee sponsors, municipalities and states on rehabilitating flood control works. The Corps will also assess how the event occurred and our response. There's always something to learn from these events. We will incorporate lessons learned into our decision-making process. The Corps will continue to work with federal and state agencies as well as levee and drainage districts on how to make basin infrastructure more resilient.

The Corps will continue to work directly with Congressional representatives, Tribal officials, state and local governments and the media,” said Helmlinger.

Missouri Basin Update

The mountain snowpack, which usually peaks around April 15, is still accumulating but at a rate that is considered average. A considerable amount of plains snowmelt is entering Missouri River Mainstem reservoirs in North Dakota and South Dakota.

The inflows are primarily in the reservoirs at Oahe Dam and Fort Randall Dam. System releases are being adjusted as a result.

Release Forecast:

Gavins Point Dam:

  • Sunday, March 31: 39,000 cfs
  • Wednesday, April 3: 42,000 cfs
  • Thursday, April 4: incremental increases from 2,000 to 4,000 cfs with a target release rate of 55,000 cfs

Gavins Point release changes take two to three days to reach Omaha, three to four days to reach Nebraska City, and four to five days to reach Kansas City, Missouri.

Release schedules are subject to change as basin conditions change.

“It is important to note that Oahe and Fort Randall Dams are the two southern or lower most storage reservoirs in the system. The spring runoff season is just beginning. Having very high pools in the lower reservoirs at this time of year severely limits the Corps’ ability to respond to rainfall events that may occur anywhere in the basin. To provide for the greatest degree of flood risk reduction throughout the runoff season, it is important to create some room in these two reservoirs,” said John Remus, chief of the Corps’ Missouri River Water Management Division.

Reservoir Status:

Fort Peck Dam

  • Inflow: 35,000 cubic feet per second (cfs) (down from 42,000 cfs on Wednesday)
  • Release: 6,800 cfs (unchanged since Wednesday)
  • Pool elevation: 2237.28 feet (up 0.3 feet in the past 24 hours)

Garrison Dam

  • Inflow: 158,000 cfs (up from 93,000 cfs on Wednesday)
  • Release: 13,300 cfs (unchanged since Wednesday)
  • Pool elevation: 1840.3 feet (up 0.9 feet in the past 24 hours)

Oahe Dam

  • Inflow: 151 cfs (up from 130,000 cfs on Wednesday)
  • Release: 4,800 cfs (unchanged since Wednesday)
  • Pool elevation: 1612.7 feet (up 0.8 feet in the past 24 hours.)
  • Notes: The pool is forecast to enter the exclusive flood control zone in the next few days due to runoff from plains snowmelt. The base of the flood control zone is 1617 feet.)

Big Bend Dam

  • Inflow: 33,000 cfs (unchanged since Wednesday)
  • Release: 32,600 cfs (unchanged since Wednesday)
  • Pool elevation: 1421.3 feet (unchanged since Wednesday)
  • Notes: Big Bend is a re-regulation project and has very little flood control storage.

Fort Randall Dam

  • Inflow: 70,000 cfs (up from 64,000 cfs on Wednesday)
  • Release: 23,000 cfs (up from 8,000 cfs on Wednesday)
  • Pool elevation: 1366.1 feet (up 1 foot in the last 24 hours)
  • Note: The base of the exclusive flood control pool is 1365 feet, which means 1.1 feet of the exclusive flood control pool is occupied.

Gavins Point Dam

  • Inflow: 27,00 cfs (unchanged since Wednesday)
  • Release: 36,000 cfs (up from 30,000 on Wednesday)
  • Pool elevation: 1205.92 feet (down 0.7 feet in the last 24 hours)
  • Note: Gavins Point Dam is a re-regulation project with very little flood control storage.

“I realize these higher system releases will add water to the lower river. However, maintaining high pool levels at Fort Randall and Oahe increases the risk of even higher, possibly flood level, releases if we were to have a large rainfall event over the central Great Plains. Releasing this water now, will create some space that will allow us to better respond to rainfall events throughout the basin. Our next official runoff forecast will be released April 1,” said Remus.

The entire Missouri River Mainstem Reservoir System has 11.5 million acre-feet (MAF) of the 16.3 MAF of flood control storage available to store upper basin runoff.

Release changes are shared with the National Weather Service, the official forecasting agency for the US Government. The public should look to the National Weather Service for forecasts and flood warnings at https://www.weather.gov/mbrfc/.



 


Contact
Eileen Williamson
402-996-3802
eileen.l.williamson@usace.army.mil

Release no. 19-021