Long Term Resource Monitoring Program Procedures: Water surface elevation and discharge
Dates
Publication Date
1995-08
Summary
Water surface elevations and discharge data are critical physical factors which influence other ecosystem components in the river floodplain. All other components listed in the Long Term Resource Monitoring Program (LTRMP) Operating Plan (USFWS 1992), including floodplain elevation, water quality, vegetation, sediment composition, macroinvertebrates, fish and wildlife, and habitat are affected by water surface elevation and discharge. Water surface elevation and discharge are directly related in uncontrolled rivers. River discharge is usually estimated from water surface elevations, assuming that the bottom geometry remains constant. However, this relationship is negated at many of the stations within the Upper Mississippi [...]
Summary
Water surface elevations and discharge data are critical physical factors which influence other ecosystem
components in the river floodplain. All other components listed in the Long Term Resource Monitoring
Program (LTRMP) Operating Plan (USFWS 1992), including floodplain elevation, water quality,
vegetation, sediment composition, macroinvertebrates, fish and wildlife, and habitat are affected by water
surface elevation and discharge.
Water surface elevation and discharge are directly related in uncontrolled rivers. River discharge is
usually estimated from water surface elevations, assuming that the bottom geometry remains constant.
However, this relationship is negated at many of the stations within the Upper Mississippi River System
(UMRS) due to a series of 36 lock and dams. For this reason, separate databases are maintained for water
surface elevation and discharge.
Water surface elevation and discharge data are not collected by the LTRMP but are obtained from other
agencies that collect these data as one of their mandates. Within the UMRS, water surface elevation data
are collected by three district offices of the U.S. Army Corps of Engineers (Corps): St. Paul, Rock Island,
and St. Louis. Discharge data are collected by the U.S. Geological Survey (USGS) by four state offices:
Illinois, Iowa, Minnesota, and Missouri. These agencies have most of the historical record for both
variables in electronic form. Data are available from as early as 1861, although data collection at most
stations was initiated for years after 1930.
The databases developed by the LTRMP contain data only from stations under the Environmental
Management Program (EMP), which includes the navigable portions of the Mississippi, St. Croix, and
Illinois Rivers. Data for special projects can be obtained from the USGS and Corps for tributary stations.
