Creating Diverse Habitat Environment in Ecological Water Resources Management

摘要

Recent developments in instream flow methodology have shifted from minimumflow regulation to the regime-based approach, recognizing that natural streamflowvariation is an essential component in sustaining aquatic ecosystem biodiversity.However, when restoring streamflow variability within a water resourcesmanagement project, it is difficult to precisely connect a specific species orcommunity to its flow variability requirements. One alternate approach is topotentially promote aquatic biodiversity by increasing both the spatial and temporalhabitat diversity of a river system.In this paper, a two dimensional numerical model is used to simulate depth andvelocity distributions for multiple streamflow conditions at a stream sectiondownstream of a reservoir. The model is based on depth-averaged theory and isspecific to an alluvial river with a movable bed. Fuzzy concepts are applied tomodeled pools, riffles, and other habitat units – which are defined by depth andvelocity – to assign approximately 290,000 mesh areas of the numerical model underdifferent streamflow conditions. Both spatial and temporal habitat variation isevaluated to indicate which set of streamflow conditions maintains the more diversehabitat objective. This allows downstream flow-based habitat diversity to become anecological objective of reservoir operation.