MD-DE-DC Water Science Center
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Slide 18 of 26
Stage is the level of the stream above some datum. It is, therefore, important that datum does not change. It is not uncommon, however, for gage structures and staff gages to be damaged by high flows and/or settle over time. If datum changes go unrecognized, incorrect estimates of discharge will result.
Three or more benchmarks, or reference marks, are maintained at all USGS gaging stations to provide checks on datum. Level surveys are run between benchmarks, reference marks, staff gages and gage structures every few years. Level surveys are run more regularly at sites known to be unstable.
U.S. Department of the Interior |
U.S. Geological Survey
URL: http://md.water.usgs.gov/publications/presentations/md-de-dc_rt98/sld018.htm
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Page Last Modified:
Friday, May 30, 2008
