Sediment-water interface position changes

If we assume a coordinate system in which the sediment water interface is at zero depth, z, with positive downward (i.e. the boundary is moving rvith respect to the center of the Earth as the sediment accumulates), the change in property, p, at a given depth, x, below the sediment-water interface is given by ... 

Whereas in Chapter 4 interactions between suspended particles and dissolved constituents have been described, Chapter 5 focusses on the processes taking place within the sediment or near the sediment/water interface. These processes depend on a large extent on the position of the oxic-anoxic interface. This interface (redoxcline) is within the sediments of well-mixed waterbodies and in the water column of some stratified lakes and basins. Transport processes and changes in the chemical environment determine the behaviour of contaminants (Salomons et al., 1987). ... 

Resuspension may be conveniently defined as the net transfer of sediment from bottom sediment into the water column. Since the gross transfer of sediment is called erosion, resuspension is the net result of bottom erosion and deposition of suspended sediment. Transfer of sediment changes the wave-mean-suspended sediment concentration with elevation 2 (= z + h, conveniently chosen as the coordinate with respect to the rigid bed as datum) and time t. This choice of datum means that, referring to Fig. 27.3 the rigid-bed level, the static-bed level and the mean position of the fluid mud-water interface are one and same. Fluid mud, if it occurs above this level is taken to be within the water layer (above z = 0). The concentration C z, t) is obtained from the simple sediment mass balance equation in the vertical direction ... 

---