USGS Home
Contact USGS
Search USGS

Home/ Overview/ Science Programs/ Data Library/ Products and Publications/States/ Rivers/Teachers and Students/ Links/ Contact/ Search

Investigating the Changing Relationship between Water Levels and Discharge on the Mississippi and Missouri Rivers

Billions of dollars in flood damages have occurred along the Mississippi River and its tributaries in the last few years. In that same time frame, thousands of acres of what was previously aquatic habitat are now lost during low summer flows. Scientists can, however, develop alternative management strategies that may limit harmful flood and drought effects. We can develop these strategies by investigating the changing relations among water levels, discharges, average velocities, and river widths and depths and linking them to human-made changes in the watershed.

By studying daily data collected for the last 50 years by the U.S. Geological Survey and the U.S. Army Corps of Engineers, we found that the relation between discharge and water levels has drastically changed. At St. Louis, the station with the longest period of record, water elevations are approximately 8 feet higher now at the same high discharge than they were in the 1800s. Water levels at the same summer low discharges are about 7 feet lower than historical records, severely affecting aquatic areas. However, the effects do not appear to be the same at all stations.

Using handwritten reports, we have recently developed an electronic database for river widths, average depths, and average velocities at six stations on the Mississippi and Missouri Rivers. These new data are being analyzed using graphical and regression techniques to gain insights into the changing relations among hydrodynamic variables, and will be related to major changes in the floodplain such as the building of levees, reservoirs, and wing dams. The work involves data collected at numerous locations on the UMR between Minneapolis, Minnesota, and the confluence of the Mississippi and Ohio Rivers including the states of Illinois, Iowa, Missouri, Minnesota, and Wisconsin.

The project was completed in September 2001.