Suspended solids concentrations and river water chemistry

Abstract

In some rivers concentrations of suspended solids are influenced to a large degree by the chemistry of the river water. This is particularly true for rivers with fine sediments draining areas where soils have high percentages of exchangeable sodium and where changes in the electrolyte concentrations during hydrologic events result in an alternation between conditions favouring dispersion and those favouring flocculation. This relationship is illustrated for low flow conditions by data from a small river in Eastern Australia.At high flows, variations in suspended solids concentrations independent of those resulting from changes in discharge and erosion are difficult to establish. However, in semi-arid regions high concentrations of clay and silt may sometimes be transported. The way such concentrations reflect changes in water chemistry is illustrated by a flash flood from Morocco and by data from the Moreau River in South Dakota. A contrasting example from Northern England describes conditions where the water chemistry produces dispersion and high suspended solids concentrations.The relationship between electrolyte concentration, exchangeable sodium percentage and suspended solids concentrations is described for each drainage basin. Such relationships provide an insight into the nature of erosion processes in a catchment and help to explain why suspended solids concentrations at low flows may be so variable.

9.31 Dryland Fluvial Environments: Assessing Distinctiveness and Diversity from a Global Perspective

“…Suspended sediment concentrations (SSCs) are highly variable but have exceeded 100 g l À1 in some dryland rivers (Beverage and Culbertson, 1964;Nordin, 1964;Gerson, 1977;Butcher and Thornes, 1978;Imeson and Verstraten, 1981;Sharma et al, 1984b;Frostick et al, 1983;Reid and Frostick, 1987;. Suspended sediment concentrations (SSCs) are highly variable but have exceeded 100 g l À1 in some dryland rivers (Beverage and Culbertson, 1964;Nordin, 1964;Gerson, 1977;Butcher and Thornes, 1978;Imeson and Verstraten, 1981;Sharma et al, 1984b;Frostick et al, 1983;Reid and Frostick, 1987;.…”

Piping Hazard on Collapsible and Dispersive Soils in Europe

“…Imeson and Verstraten (1981) have also explained that the well-documented correlation between erosion and rainfall intensity occurs not only because of rainfall energy, but also because during a rainfall event variations in the soil solution salt dilution occur, complicating (but largely enhancing) deflocculation and dispersion. The significance for sediment entrainment and erosion is clear from Figure 2.6.10, where it can be seen how that the dispersion threshold is enhanced and dispersion persists during a flash flood in Morocco.…”

Effects of dissolved organic matter and suspended solids on the magnetophoretic separation of microalgal cells from an aqueous environment

“…It has been reported that the average concentration of suspended solids for ground water is approximately 200 mg/L and can approach 600 mg/L in some extreme cases [45,46]. Hence, our experiment was performed in the concentration range of 50-750 mg/L of silica colloid to cover the typical and extreme ranges of suspended solids.…”