Relationship of unmeasured sediment discharge to mean velocity

Abstract

Unmeasured sediment discharges were computed by subtracting the measured suspended‐sediment discharges at alluvial sections from total sediment discharges that had been either measured at nearby contracted sections or computed from the modified Einstein procedure. Average curves show a general increase of unmeasured sediment discharge per foot of stream width as a function of about the third power of the mean velocity. At constant mean velocity the unmeasured sediment discharge per foot of width generally increases with concentration, especially with suspended sands concentration adjusted for depth of stream Such adjusted concentrations of suspended sands seems t o be reasonably good measures of the availability of sands. This availability is the relative rate of transport of sands for a given condition of flow and is related to particle sizes and cohesiveness of sediments of the stream bed and banks. Relationships of unmeasured sediment discharge to mean velocity and to concentration can be applied successfully in several kinds of sediment computations.

A study of fluvial characteristics and hydraulic variables middle Rio Grande, New Mexico

“…To study changes over a reach, however, readings must be obtained at several sections to draw any general conclusions. The only data available for which several cross sections in a reach were measured over a period of tune are the observations in 1952 near Bernalillo andin 1957 and1958 at Casa Colorada. Near Bernalillo, 13 cross sections were measured 6 times during the spring runoff of 1952. The patterns of scour and fill were not similar at the different cross sections.…”

“…Colby (1957) and others stated that total load is related to the cube of the mean velocity. If this is so the adjustment ratio for lower-to upper-regime loads (l+J5s/56)(C2/Ci), should be predictable from the depth-velocity relation.…”

Fluvial sediment of the Mississippi River at St. Louis, Missouri

“…The bed-material discharges increased with about the fifth power of the mean velocity. Colby (1957) presented a method for computing unmeasured sediment discharge from the relation to mean velocity, depth, and concentration of suspended sands. Total bed-material discharges can be computed by adding the unmeasured sediment discharge to the measured bed-material discharge.…”

Chemical quality of surface waters, and sedimentation in the Grand River drainage basin, North and South Dakota

“…Suspended-sediment records were also obtained on the Grand River near Wakpala by the Corps of Engineers from April 1947 to September 1951(U.S. Army Corps of Engineers, 1951,1957.…”