By CourtesyJanuary 2, 2019
By D. Peter Helmlinger
The writer, a brigadier general, is commander of the Northwestern Division of the U.S. Army Corps of Engineers.
Living in the Midlands, you probably noticed a lot of water flowing down the Missouri River this year. The reason is 2018 had remarkably high runoff - the third highest in 120 years of recordkeeping.
This year, engineers and scientists in the U.S. Army Corps of Engineers' Missouri River Basin Water Management Division effectively managed 41.3 million acre feet of runoff. Only 1997, at 49 million acre feet, and 2011 at a record 61 million acre feet, were higher.
True, Williston, North Dakota; communities between Fort Randall and Gavins Point dams; and locations downstream of Gavins Point Dam saw higher-than-normal river stages, and the Missouri River Mainstem System dams (System) made higher-than-normal releases. But, the System performed as designed, and we did not see the widespread flooding that would have happened without the System.
We are mindful that flooding along the river is challenging for all, and we do our best to minimize that reality when we can, consistent with other operational requirements. I believe the Corps' water managers did just that in 2018.
Twice a year, my staff hosts public meetings throughout the basin to present the range of conditions and forecasts that determine how they operate the System.
November's meetings were well attended. Attendees can learn how we watch and study the Missouri River and runoff to make the decisions we do. If you haven't been to a meeting, I recommend it.
We must operate the System for those purposes authorized by Congress. Those include flood control, navigation, hydropower, water supply, irrigation, water quality control, recreation, and fish and wildlife -- including threatened and endangered species.
Normally, water released through the System supports navigation, at the same time generating power, providing water quality control and ensuring access to water for irrigation, and for municipal and industrial needs. As a result, people can reliably boat, fish, camp, hike, etc.
Missouri Basin runoff is a combination of mountain snowpack, plains snow, and rainfall. Not knowing when and how fast the snow will melt; and where, when, and how much rain will fall is why water managers continually monitor basin conditions.
In mid-March, Corps' water managers increased the service level for potential releases from Gavins Point Dam as mountain snowpack kept growing. The service level sets potential minimum and maximum releases based on existing and forecast runoff and stored water. They couldn't increase releases because the river was still frozen in places. But they were already communicating potentially higher-than-normal releases.
Rainfall in Montana during May and June accelerated mountain snow melt, adding to the runoff. In June and July, System reservoirs reached storage levels reserved exclusively for extremely high runoff.
For Yankton and Sioux Falls, South Dakota, 2018 is the wettest year on record. The Big Sioux, Elkhorn, Floyd, James, and Niobrara rivers and the Missouri River downstream from Gavins Point Dam -- where flows are unregulated by dams -- saw annual precipitation 8 to 20 inches above normal.
Knowing higher-than-average river levels are challenging for those along the river, a few times, when models showed we could lessen flooding impacts after a rain event, we reduced releases.
We expect 2018's runoff from will exit the System by early February. All 16.3 million acre feet of space allocated for flood control storage should be available for the 2019 runoff season.
The National Weather Service's winter outlook is generally warmer and drier for the upper basin. However, they remind me we can still have blizzards, droughts, downpours, and heat waves.
Sharing this information is important. We try to reach as many people as possible.
Our efforts to keep you informed via public meetings, media, websites, and social media offer insight of how decisions are made.
Stay informed at www.nwd.usace.army.mil/mrwm. "Weekly Updates" are published every Tuesday and the "News" section has the latest news with detailed forecasts issued the beginning of every month.
We're @NWDUSACE on Facebook and Twitter. And we hope to see you at our public meetings in April.