Public Release: 

As The Red River Floodwaters Recede, USGS Continues Measuring Flood Effects With Cooperation Of State Agencies

US Geological Survey

Even as the floodwaters of the Red River of the North continue to recede, and residents begin to deal with the aftermath of the unprecedented nature of this rare flood, the U.S. Geological Survey, in cooperation with several bi-state agencies, is making additional streamflow and water-quality measurements to assess the overall impact of the flood.

The weekly sampling of the Red River at various locations on its northward flow to Canada will be done over the next four weeks, according to Doug Emerson, USGS hydrologist in Bismarck, N.Dak.

In the aftermath of a flood, USGS crews continue to monitor the flow of the affected river in order to build a comprehensive profile of the flood, to track evidence of scour at bridges that can be severely eroded and destabilized during floods, and to sample water quality to determine the presence and movement of toxic chemicals and sediments as the result of the flooding.

USGS crews are also busy repairing streamflow-gaging stations in order to continue to provide the essential information on the flow of the Red River and other streams to the National Weather Service, the U.S. Army Corps of Engineers, and other Federal, State, and local agencies that have flood-warning and flood-modeling responsibilities.

The Red River, which crested about 54 feet at Grand Forks on April 21 exceeded the maximum recorded stage set in 1897 by about 4 feet.

Discharge measurements of the volume of streamflow in the Red River and water-quality sampling will be done at Grand Forks and Pembina -- two key locations on the river. The water-quality measurements will be done using a technical protocol or series of samplings devised as part of the USGS National Water-Quality Assessment Program.

The national water-quality program, which is investigating the status and trends of water quality at 60 sites across the country over time, has developed consistent sampling procedures that will help to provide a good understanding of what effects the flood has had on various aspects of water quality.

The first set of measurements will begin on May 6, 1997, with sampling on the Red River at Grand Forks. Water-quality sampling will continue on May 7 on the Red River at Pembina, and discharge measurements will be made on May 8.

The Minnesota Pollution Control Agency (PCA) will assist the USGS in the collecting and processing of the water samples.

The following week, the North Dakota Department of Health will assist with measuring and sampling of the Red River at Grand Forks on May 13. Measurements will be made and samples will be collected on the Red at Pembina on May 14. The water-quality samples will be split and will be analyzed by each of three labs.

The data-collection schedule for the two following weeks will be: Red River at Grand Forks, May 20. Red River at Pembina, May 21. The Minnesota PCA will again assist in the collecting and processing of samples. Red River at Grand Forks, May 28. Red River at Pembina, May 29. The North Dakota Department of Health will again help collect and process the water samples.

In addition to the value of discharge measurements in developing flood-forecasting models and helping to understand the nature of a particular flood, streamflow discharge data collected by the USGS serve as the basis for the design of dams, bridges, water-treatment and waste-water treatment plans, and the formulation of environmental regulations.

While river stage -- or the height of the river during a flood -- is an important information component of the flood picture for the public in understanding just how high the water is , or will be, river discharge is more commonly used for technical design and scientific study. Many engineering structures, flood-control reservoirs, for example, are designed to pass, treat, or hold a volume of water for a specific period of time. In these cases, the river discharge is the primary design variable and is the piece of information that is most highly valued.

In addition, in order to use streamflow data, scientists must often transfer data collected at one site to other locations along a river course or to nearby rivers where data are not available. For most purposes, discharge data provide the most transferable information. Discharge at one site is often directly related to discharge at other sites on the same or nearby rivers, but river stages at different sites are rarely correlated as easily and usually are of limited value beyond the immediate vicinity at which they are collected.

The USGS, which maintains a nationwide network of streamflow-gaging stations, has 100 gages in North Dakota, 50 of which are in the Red River watershed, which includes stations in Minnesota. Several gages have been inundated or damaged by the flooding and the main gage at Grand Forks was inundated during the extraordinary flood. A temporary gage was set up on the deck of a local restaurant and provided critical information as the waters begin to recede by inches from the inundated city.

The USGS has made more than 300 discharge or flow measurements since the flooding began the last week in March. Crews have also been out making more than 175 inspections of gaging stations to ensure that they are operating properly.

Nationwide, 1997 has already been a year of extensive flooding. Since January 1, more than 165 USGS streamflow-gaging stations have been seriously damaged or destroyed by major floods in California and Nevada, the Pacific Northwest and the Ohio River Valley. The USGS has worked quickly to replace and repair stations and to keep the information flowing from this network. Some 12 to 15 gages in North Dakota have also been damaged, and USGS crews are working quickly to repair these gages or to install temporary gages until more permanent repairs can be made.

Through its network of 7,000 streamflow-gaging stations, which are cooperatively funded by more than 700 Federal, State and local agencies, the USGS provides vital information to the agencies responsible for flood warnings and river forecasts. Under this program, which has operated since 1887, the USGS collects streamflow information needed by Federal, State and local agencies for planning and operating water-resources projects and for watershed management, in addition to flood-warning.

In recent years, the network has changed considerably with the advent and widespread use of real-time streamflow data. More than 60 percent of the stations in the network use satellite radio transmitters to broadcast data 24-hours-a-day directly to cooperators like the National Weather Service, who in turn use the information to provide river forecasts and flood warnings. The number of stations equipped with data-collection platforms, which provide for the real-time data, has more than doubled in the past 10 years, even though the overall number of gages is decreasing.

General access to the real-time data is available through the World-Wide Web on the Internet. Those in need of information on the height and flow of a river -- from flood forecasters to fly fishers -- can access state-by-state information through the USGS main home page at: http://www.usgs.gov/. By clicking on the word "water" and then accessing "real-time streamflow," users can click on the state for which they need information and then the individual river where gaging stations are located.

In preparation for the flooding on the Red River, the USGS prepared publicly available flood tracking charts (which are also available on the Web at the North Dakota page). These colorful and easy-to-use charts can be used by local citizens and emergency response personnel to record the latest river stage and predicted flood-crest information. Instructions for using the chart are printed on the chart and are on the Web site.

The network of streamflow-gaging stations in the Red River of the North Basin is operated by the USGS in cooperation with the U.S. Army Corps of Engineers, the North Dakota State Water Commission, the Minnesota Department of Natural Resources, the Southeast Cass Water Resources District, the Red River Joint Water Resource Board, and the Red River Watershed Management Board.

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Note to Editors: The Red River Flood Tracking Chart and the current hydrographs -- showing the stage height and discharge of the Red River in real-time -- are available at http://srv1dndbmk.cr.usgs.gov/public/rrflood/rrflood.html/

The chart and the records of previous peaks and hydrographs provide interesting graphics that can be easily downloaded. For interviews and further information on the current flooding, please call Gregg Wiche or Russ Harkness, USGS, Bismarck, N.Dak., 701-250-4601.

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