ASDSO Dam Safety Toolbox

Streamflows

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“Streamflow data collected by various agencies describe the flow characteristics of a stream at a given point. Normally, data are collected by using a measuring device commonly called a stream gage. Stream flow data are used to indicate the present hydrologic conditions and the discharge amounts of a watershed and to check methods for estimating present and future conditions. Specific uses of streamflow data, presented in 210-NEH, Part 630, Chapter 9, are for determining hydrologic soil-cover complex numbers, frequency analysis (chapter 18), determining water yields (Chapter 20), and designing floodwater retarding structures (Chapter 21).”[1]

“Most reported streamflow measurements are from locations maintained over time. These are set at fairly stable areas where a consistent rating curve relating gage height stream discharge can be obtained. This rating curve has to be checked periodically and after major events to assure that it has not changed. Users can examine historic changes in the rating curve to assess channel behavior and stability over time. Stream gage locations can be placed at manmade controls such as bridges, crossings, and dams or at natural controls, such as rock canyons or otherwise stable reaches. Stream height is measured, and the rating curve is used to calculate the discharge. The data can be recorded from field observations or electronically."[1]

Best Practices Resources

National Engineering Handbook: Chapter 5 - Streamflow Data (Natural Resources Conservation Service)


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Revision ID: 5023
Revision Date: 12/06/2022