The "Mighty Mo," America's longest river, flows past communities in Montana, North Dakota, South Dakota, Nebraska, Iowa, Kansas, and Missouri – plus it receives water from Wyoming, Colorado, and Minnesota. The Izaak Walton League is working with partners throughout the region to make sure this amazing waterway stays healthy. Here's what happened along the river in February.

Basin Runoff Remains Low

The Missouri River’s upper basin’s runoff forecast continues below average. January recorded slightly above-average runoff as warmer temperatures melted some snow. It was Nebraska’s third-wettest January and the ninth-wettest January in Iowa in 129 years of record. Despite that, the Corps of Engineers is predicting below-average runoff this year as the drought persists across most of the basin. 2023 runoff is expected to be 21.1 million acre feet (MAF). If received, that’s 82 percent of average. The runoff forecast is based on soil moisture, plains and mountain snowpack, and long-term forecasts.

Water stored in the Missouri River Reservoir System is expected to be over 10 MAF below the system’s flood control zone on March 1, the start of the runoff season. Mountain snowpack is near average; the plains snowpack is slightly above average. The plains snow has two to five inches of snow water equivalent (SWE) in eastern Montana and parts of the Dakotas. The La Niña pattern that has dominated the nation’s weather for three years is expected to give way to neutral conditions this spring. Forecasters are hopeful that drought conditions may begin to lessen in the basin this year.

River Meetings Announced

The Corps’ Missouri River Basin Water Management Division will hold seven public meetings across the basin. The bi-annual meetings are designed to discuss runoff and take comments on the Corps’ operational plans for the Missouri River System. The spring meetings are scheduled in early April and locations in the tri-state area include:

• April 4 – Pierre and Lower Brule, SD
• April 5 – Omaha/Bellevue, NE

Meeting times and locations will be announced. I’ll attend the meeting in the Pierre area and submit comments on the Corps’ planned operation of the Missouri River.

Winter Weather May Result in Fish Kills

Starting in December, massive blizzards moved across the Midwest dumping heavy snow. These storms may impact fish populations in small lakes and ponds. Biologists are recording low oxygen levels, and winterkill occurs when lakes are covered by thick ice and deep snow for a lengthy period. Those conditions prevent sunlight from reaching vegetation needed to produce oxygen.

The situation is complicated by lower water levels, increasing the possibility of winterkill. After ice out, biologists will assess how many lakes suffered winterkill and determine strategies to restock lakes with high losses. These fisheries will come back but it will take several years for that to happen. The region has experienced severe winterkills in the late '70s, mid '80s, and in '96-'97.

League Comments on Garrison Dam Safety Plan

The League submitted comments to the Corps of Engineers on an Environmental Assessment for Garrison Dam on the Missouri River in North Dakota. The Corps completed a Dam Safety Modification Study and identified an alternative to reduce the dam’s safety risks. The study found six issues that could result in failure of the 70-year-old spillway. The risks were identified after the 2011 flood, the only time this spillway has been used.

The risk of a spillway or dam failure is highly unlikely. But we commended the Corps for conducting the assessment and proposing modifications to increase the dam’s safety and protect human life and downstream infrastructure. We supported Alternative 12, the Corps’ Tentatively Selected Plan (TSP), to reduce the chance of a catastrophic spillway failure.

Failure of the Garrison spillway or dam would be catastrophic for 11 states and for over 2,000 river miles from North Dakota to Mississippi. Economic losses could exceed $100 billion from an embankment or spillway breach. We urged the Corps to actively seek the funding needed for this project. Read the comment letter.

SD Division Comments on Proposed Wetland Site

The South Dakota Division submitted comments to the Natural Resource Conservation Service on a proposed wetland mitigation bank site in Minnehaha County. The project plans to restore hydrology and vegetative cover damaged by drainage and agricultural use to benefit wildlife, flood storage, and improve water quality.

The Division urged for the conservation and protection of wetlands through available programs and said wetland mitigation should be the last resort, not the first option. The Division restated prior concerns regarding monitoring of wetland bank sites. The letter mentioned it takes time to establish vegetation and repair hydrologic functions on a degraded site, and the proposed three-year monitoring period may not be enough time to determine if the site has been fully restored or established. Read the Division’s letter.

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Top photo: Snow and ice on the Missouri River. Photo credits: Paul Lepisto.