Figure 3.22b. Suspended sediment sampler-DH48 (Guy and Norman 1973, U.S.
Interagency 1952).
3.6.5 Suspended Sediment Hydrograph
The measured suspended-sediment concentration is used to plot a concentration hydrograph
(Figure 3.23). Engineering judgment, the stage hydrograph and knowledge of the stream is
used in drawing the suspended-sediment hydrograph. The Techniques of Water-Resources
Investigations of the United States Geological Survey, Book 3, Chapters C3 (Porterfield
1977) Computation of Fluvial-Sediment Discharge describes methods to construct a
suspended-sediment hydrograph.
3.6.6 Determination of Daily Suspended-Sediment Discharge
Using the concentration hydrograph an average daily suspended-sediment concentration is
determined. Using this concentration and the average daily water discharge in Equation 3.53
the average daily suspended-sediment discharge is determined.
However, If the
concentration and water discharge are changing rapidly during the day, as illustrated in
Figure 3.23, the day will have to be subdivided into short time increments. The suspended-
sediment discharge is determined for each time increment using Equation 3.53. Then, the
suspended-sediment discharge for each time increment for the day are converted to a
common time base, added up and divided by the number of common time increments to
obtain the average suspended-sediment discharge for the day.
3.49
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