ABSTRACT
In regulated stream systems, an important option exists which can be used to maintain desired channel characteristics: the programed release of a predetermined discharge for a given duration. Such releases, termed “channel maintenance” or, more commonly, “flushing flows” (for the effect of removing [flushing] fine sediments from gravels), can be applied to meet a variety of interrelated management goals. In this chapter the basis for and the theory behind such flows are discussed and methods used for making flushing flow prescriptions are presented. From a biological perspective, it can be generalized that flushing flows are needed when sediment concentrations exceed historic levels and begin to affect important aquatic habitats and life history functions. The chapter presents various methods and procedures which can be used to evaluate the effectiveness of flushing flows. Methods which utilize standard survey techniques would also be useful in assessing the effectiveness of flushing flows.
