Record Midwest Floods Threaten Communities with ‘Walls of Water’
Roughly a quarter of the 40,000 residents evacuated Minot, North Dakota’s fourth largest city due to record flooding on the Souris River.
The Souris River flows into Canada and is overtopping its levees due to heavy rainfall and releases from Canadian dams. The flooding on the Souris breaks the 1881 record and the river is expected to rise as much as 6 to 7 feet higher over the weekend.
Meanwhile, heavy rains earlier this week fell across South Dakota and northern Nebraska with as much as 6-inches inundating parts of South Dakota, causing the Missouri River to rise higher and flow faster. Our hearts go out to the communities who are threatened by this flooding, many of whom are preparing to evacuate their homes to escape damages from levee overtopping and breaching in Missouri, Kansas, Iowa, and Nebraska.
Currently, The Missouri River elevation at Gavins Point Dam is 1208 feet, just 2 feet from the top of the spillway gates. The Corps of Engineers will release an immense 160,000 cubic feet per second (cfs) flow, 10,000 cfs more than the current average and more than double the record 70,000 cfs back in 1997.
A mile and a half long dam on the Nebraska/South Dakota border that forms the Lewis & Clark Reservoir, Gavin’s Point is last in a series six large dams along the Missouri River, designed for controlling water for navigation, flood control, recreation, among other uses.
The dams along the Missouri River were designed and built more than 50 – 80 years ago when engineers couldn’t have predicted these intense and frequent rainfall events, the record snow pack that is late to melt, or the development that has placed people in harm’s way and caused a huge loss of natural floodplains that store and convey floodwaters.
Today we are left with a legacy of an engineered system where large, structural projects have transformed the once natural Missouri River that Lewis and Clark knew. The Missouri River is a system of highly managed “buckets” that are spilled or not spilled depending on which use is competing the strongest.
The sober reality is that we can’t build our way out of the flooding problem. Large structural projects like levees and dams have high operation and maintenance costs and can and do fail, often with catastrophic consequences, as we are seeing today.
While we can’t return to the days of Lewis and Clark, we can begin to study and plan for innovative solutions that allow room for the river – building out so to speak, not up. Investing in protecting and restoring our “natural defenses” will help communities become more resilient as we continue to weather more frequent and intense storm events that will come with a changing climate.
These solutions must include options like moving people out of harm’s way, protecting and restoring floodplains, investing in floodways and bypasses, notching levees or setting levees back among other nonstructural solutions that can store and convey floodwaters naturally.