SEDIMENT IN RELATION TO WATER QUALITY1

Abstract

ABSTRACTThe relation between sediment and water quality involves the individual relations between sediment and the physical, chemical, and biological characteristics of water as these characteristics determine the suitability of water for an intended use. Both the physical and chemical properties of fine‐grained sediments must be considered in evaluating these relations, whereas only the physical properties of coarse‐grained sediments are significant. Most of the literature concerning this subject has considered sediment only as a physical entity. In amount, it is the prime pollutant and is one of the major considerations in evaluating the suitability of water for an intended use. Losses in the United States from sediment and associated flood water damages are measured in billions of dollars annually. Sediments also indirectly affect water suitability through their (physical) influences on biological activity. Fine‐grained sediments, that is, clay minerals and amorphous and organic materials, have chemically active surfaces. These sediments may either sorb ions from solution or release ions to solution depending upon the chemical environment. Unfortunately, not enough is known about the ternary system–sediment‐water‐dissolved chemical load–to adequately define its influence on either the biological characteristics of water or the suitability of water for various long‐term uses. This paper attempts to define the problems concerning the role of sediment in this ternary system.