With its headwaters in the Rocky Mountains and flowing some 2,300 miles, the Missouri River Basin is the longest tributary on the Mississippi River. Its major tributaries include the Platte, Yellowstone, Kansas and James rivers. Historically, the untamed Missouri River produced violent floods in the spring and summer, with erosion eating away its banks and muddying its waters. River flow is heavily impacted by low and extremely varied precipitation across the watershed. A series of levees and dikes support navigation in the lower section from the junction with the Mississippi River upstream to Sioux City, Iowa. The middle section includes six large dams that create the largest reservoir storage system in the world by volume and support flood control and risk management, navigation, fish and wildlife habitat, water supply, recreation and irrigation.
Photo: Mark Godfrey
Photo: US Army Corps of Engineers
Photo: US Army Corps of Engineers
The Missouri River Basin received an average C grade in the report card, much because of poor scores resulting from challenging issues in ecosystems and water Supply. The Missouri scored well in the number of hunting and fishing licenses issued. It also has a higher number of communities with building elevation requirements for flood control preparedness. However, there were a high number of communities with water supply systems reporting treatment violations and water depletion was high. Because navigation in the Missouri Basin is not reliant on locks and dams, the report card for navigation only includes information about overall system maintenance.
The Missouri River Basin represents the largest area of the tributary watersheds and has a high percentage of its area in the drier western portion of the Mississippi River Watershed. Therefore, water allocation issues and issues related to flood control and flow management continue to be challenging in this region.
Grades Explained by Goal
The Missouri River Basin received a grade of D for Ecosystems. The Living Resources indicator received a C while the Streamside Habitat indicator received a grade of C+. The Water Quality indicator received a C and the Wetland Area Change indicator received an F grade, the lowest in the watershed.
The Missouri River Basin received a C grade for Flood Control & Risk Reduction. The Floodplain Population Change indicator in the Missouri River Basin received a C grade. The Levee Condition indicator received a C grade and the Building Elevation indicator received a B grade, one of two basins with this highest grade.
Grading the Transportation goal in the Missouri Basin was a challenge for the Report Card. The Missouri basin is an outlier because there are no locks used for navigation. Based on input from stakeholders and significant feedback from experts throughout the watershed, two of the three indicators for the overall transportation goal measure the condition of the physical infrastructure for navigation and the performance of lock facilities. These indicators do not apply to the Missouri Basin, and for this reason, the Report Card does not assign a grade to the transportation goal specific to this basin. However, transportation in the basin is compromised by the lack of adequate funding for maintenance, because this affects the management of the entire inland waterway network.
The volume of transportation activity in the Missouri River basin is substantially smaller than in the other basins. Recent years have seen an increase in the volume of activity following a low point around 2009. The volume of river born transportation on the Missouri River however remains below levels seen in the early 1980s.
The Missouri Basin received a grade of D for Water Supply. The Treatment Violations Indicator in the Missouri Basin received a D grade while the Water Depletion indicator received a D+ grade, making it the basin facing the most pressing water supply concerns.
The Missouri River Basin received an overall grade of C- for Economy. The River Dependent Employment indicator in the Lower Mississippi received a D+ grad