Impacts of A Persisting Flood On The Missouri River’s Bank Stabilization and Navigation Project

The Missouri River experienced sustained high flows both in 2019 and 2020. Levee overtoppings and breaches experienced throughout the lower basin during the 2019 flood event visibly showcased the impacts of the sustained high flows on the upper portions of the floodplain. However, the lower portions of this sand bed river also experienced dramatic, evolving changes that remained hidden under the high stages. The Bank Stabilization and Navigation Project (BSNP) of the Missouri River is composed of stone river training structures to provide a self-scouring navigation channel to meet the authorized channel dimensions of 9 ft by 300 ft. Navigation impacts were noted throughout 735 miles of the BSNP as flow dropped rapidly from above-average discharges to near below average discharge in 2020. Shifting shoals within the navigation channel developed as the riverbed adjusted to the change in flow and sediment loads and was exacerbated by damages to river training structures. Communication of field observations and engineering responses by the Kansas City District of the United States Army Corps of Engineers are shared as lessons learned for managing engineered features of a navigation channel on an alluvial river.