Introduction

Sediment is critical to the river’s native fish, wildlife and vegetation. Changes in the location and amount of sediment deposition and erosion along the river corridor affect habitat areas for different species. Proper management of sediment resources along the river is vital to retaining and developing this habitat, as well as maintaining existing river uses. A number of factors can cause an imbalance in river sediment. Major factors include: development and operation of reservoirs, creation of navigation channels, increased water use, sediment mining and changes in land use [Missouri River Recovery Program].

The objective of this project is to describe the spatial and temporal variation of sediment yield within the Missouri River basin in order to provide a perspective on the spatial and temporal patterns of sediment yield. The temporal variation of the sediment yield is examined by comparing data collected in different decades. For spatial analysis, 363 survey data about sediment behind dams in the basin, are used.

The Missouri River

The Missouri River, the longest river in the USA, travels over 3,700 Km from Three Forks, Montana, to join the Mississipi River near St. Louis. For centuries, the river has served as the centre of life for the inhabitants of North America's Great Plains. Historically, the Missouri River has produced high floods that eroded its banks and turned its waters turbid in the spring and summer. Over the years, the U.S. Army Corps of Engineers has been charged by the Congress to remove snags, protect banks, construct navigation channels and build flood risk management structures (levees and dams) on the Missouri River to provide social and economic benefits. Some of these development activities on the Missouri River have had lots of impact on the rivers native fish and wildlife.

Shortly after the Missouri River dams began operating, sediment began to deposit where streams entered the reservoir pools, resulting in sediment deposits above the dams. In the free-flowing river between and immediately downstream of the dams, the sediment transport capacity exceeds the sediment supply. That is, the river is able to carry much more sediment than is available. In addition to the construction of the dams, other projects such as the Bank Stabilization and Navigation Project (BSNP), tributary development and conservation practices that reduce sediment runoff and erosion into the Missouri River basin have also contributed to the change in sediment yield. The reduction in sediment availability from the banks and tributaries has resulted in a deepening of the river in certain areas due to the river bed erosion. In some areas, erosion downstream of the dams has caused losses of agricultural and forest lands, degraded wetlands and damaged irrigation intakes. Sediment losses also cause problems for the river’s native species[Missouri River Recovery Program].

The Missouri River Recovery Program, a program supported by federal agencies, attempts to implement actions to accomplish Missouri River ecosystem recovery goals in coordination and collaboration with agency partners and stakeholders. The objective of the program is to create a sustainable ecosystem supporting thriving populations of native species while providing for current social and economic values [Missouri River Recovery Program].

Missouri River Recovery Program Video.

Data

Before starting the analysis, all data are converted to the projection-based coordinate system:

Projected Coordinate System:        NAD_1983_Albers

Geographic Coordinate System:     GCS_North_American_1983