Instream Flow Methodologies for Regional and National Assessments

摘要

This paper is largely an in-depth documentation of the effort made over a four year period to consider instream flow values as part of the Water Resources Council's Second National Water Assessment. It includes a summary of methodologies available in 1974, the series of revisions made in arriving at the final Instream Flow approximations published in the Assessment, the analysis of depletion ratios made in the resources of the 106 assessment subregions and the legal and institutional aspects relative to instream flow. It also summarizes a new method developed subsequent to the National Assessment effort which offers promise of providing an improved basis for assessing instream flow needs for level A and B planning studies.