USE OF HYDRAULIC MODELLING TO ASSESS PASSAGE FLOW CONNECTIVITY FOR SALMON IN STREAMS

摘要: The maintenance of hydrologic connectivity in river networks has become an important principle for guiding management and conservation planning threatened salmon populations, yet our understanding how fish movement is impaired by spatial temporal variation remains limited. In this study, a two-dimensional hydraulic modelling approach presented to evaluate flow relation passage requirements adult steelhead trout (Oncorhynchus mykiss) coastal California streams. High-resolution topographic data stream reaches with distinct channel morphology were collected using terrestrial light detection ranging surveys linked water surface measurements calibrate model simulations. Quantitative metrics longitudinal developed assess suitability discharge. Measured from the 2008–2009 winter season simulated long-term records indicated that suitable flows occur relatively low frequency duration at all sites, suggesting instream protections are warranted. Results simulations then compared two alternative methods assessing flows. A regional formula used State identify minimum needs provided conservative estimates requirements, whereas based on riffle crest depths underestimated needs. appears well suited simulating studies may be particularly useful testing environmental assessment evaluating habitat–flow relationships importance, such as critical habitat species. Copyright © 2011 John Wiley & Sons, Ltd.