Feb 10, 2020 6:51 PM

Soil saturation raises flood concerns this spring

Posted Feb 10, 2020 6:51 PM


St. Joseph Post

Saturated soil throughout the Missouri River Basin makes flooding more likely this spring.

Kevin Lowe with the National Weather Service says snowpack in the mountains is about normal this winter so far. But very wet soil has already caused some problems along the Missouri River.

“During the past month, we’ve experienced minor to moderate flooding along many of the tributaries to the Missouri River in the state of Missouri and the main stem Missouri River itself has been in flood (stage) in the lower 100 miles,” Lowe tells a conference call arranged by the U.S. Army Corps of Engineers.

Lowe says there also have been ice jams on the Platte, North Platte, Elkhorn, and Middle Loup Rivers in Nebraska as well as on the Missouri River itself north of Omaha.

Lowe says the saturation will prevent soil from absorbing rain this spring, increasing the amount of runoff.

Upper Missouri River Basin runoff last year totaled 60.9 million acre feet, just off the record 61 million acre feet runoff of 2011. The Corps of Engineers estimates the runoff this year will total 36.3 million acre feet, which would rank ninth in 122 years of record keeping.

Lowe says heavy rain throughout last year and conditions this winter have not allowed the ground to dry, with above normal soil moisture through almost the entire Missouri River Basin.

“In the Dakotas, we’re in the 99 percentile according to one estimate, meaning that I think over the past 50 years I believe this is in the top 1% of the 50 years with regard to how wet it is,” Lowe says. “So, we’re very wet.”

Lowe says that means whatever snowpack and rainfall falls on the ground this spring, it is going to run off.

“So, that definitely gives us a higher risk for flooding,” Lowe says.

Missouri River Basin Water Management Chief John Remus with the Corps of Engineers says the conditions have his attention.

“The analogy I use is a sponge, a wet sponge and a dry sponge,” Remus says. “And, right now, the sponge is pretty wet in the upper basin, so you’re not going to be able to get any water to soak in.”

Water releases at Gavins Point Dam are at 35,000 cubic feet per second, twice the normal winter release, as the Corps attempts to prepare the upper Missouri River reservoirs to take in the larger than normal runoff and prevent further flooding.