Movement and deposition of sediment in the vicinity of debris‐barriers

Abstract

Accelerated erosion and the scour and deposition of sediment in streams have had, in many instances, harmful effects on the use of valley‐floors as residential areas and for farming and grazing. Perhaps the outstanding significance of streams carrying a relatively large sediment‐load is the effect on the silting of large reservoirs, the silting‐rates of which determine not only the life of these reservoirs for flood‐control purposes, but also the perpetuity of agriculture, cities, and industries, which are dependent on the water stored.

Unintended consequences of restoration: Loss of riffles and gravel substrates following weir installation

“…Engineering guidelines typically suggest that structures should be spaced such that the upstream structure does not interfere with the deposition zone of the next downstream structure (Heed and Mulich, 1973). Approximate spacing can be determined by extending a line from the top of the first downstream structure at the equilibrium slope upstream until it intersects the original streambed (Johnson and Minaker, 1944), thus defining the length of the deposition zone upstream from the structure (Mussetter, 1982).…”

Channel Rehabilitation: Processes, Design, and Implementation

“…Mussetter (1982) showed that the optimum spacing should be the length of the deposition above the structure that is a function of the deposition slope ( Figure 6.12). Figure 6.12 also illustrates the recommendations of Johnson and Minaker (1944), that the most desirable spacing can be determined by extending a line from the top of the first structure at a slope equal to the maximum equilibrium slope of sediment upstream until it intersects the original streambed. However, each of the above references implicitly includes a specific sediment supply concentration, and that concentration is necessary for rational designs.…”