Résumé :
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Hydraulic simulation for instream flow studies is defined as the description of the changes in distribution of velocities, dephts, and substrates as a function of discharge. These changes are described in mathematical terms to facilitate the quantification of change in discharge. The type of hydraulic simulation technique appropriate for a certain situation depends on the degree of resolution required for the study, the characteristics of the stream, and the limitations inherent in the technique. Several types of techniques for the prediction of the stage-discharge relationship and the velocity distribution-discharge relation-ship are presented. General limitation and site imposed constraints pertaining toeach type of simulation technique are also presented. The type of study site selected depends on the assumption that the study site is critical to the species under study, or that the study site is representative of a larger reach of stream. Either assumption may be implied or expressed in an instream flow methodology, and the involves the strategic placement of transects which describe certain types of conditions or habitat areas within the channel. Further, the characteristics of the study site may have profound influences on one's ability to simulate the hydraulics of the stream. Data requirements and precision specifications are provided, as well as guidelines for efficient data collection. Several appendices are included which detail data collection procedures for each type of data required for hydraulic simulation. The appendices also detail methods for collecting hydraulic simullation. The appendices also detail methods for collecting hydraulic data in large rivers, as well as equipment neede for such data collection. Finally, a brief description of several computer programs for hydraulic simulation is given in the appendices.
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