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<br />The following User Guide is intended to familiarize the user with the <br /> <br /> <br />Simplified Dam Break Model's data requirements and the computations it <br /> <br /> <br />performs in producing the information necessary for delineating endangered <br /> <br /> <br />areas downstream of a failed dam. Briefly stated the model calculates the <br /> <br /> <br />maximum outflow at the dam, evaluates how this flow will be reduced as it <br /> <br /> <br />moves from the dam to the downstream point(s) specified by the user, <br /> <br />determines the depth attained by this flow at the point(s) and finally <br /> <br /> <br />computes the time required for the flow to reach the point(s). All of these <br /> <br />calculations utilize information (data) supplied by the user, a summary of <br /> <br /> <br />which is given below. The user should note that while the model supplies <br /> <br /> <br />default values for many of these input variables, the most accurate results <br /> <br /> <br />are produced when the most accurate data is entered and the authors strongly <br /> <br /> <br />urge the use of the best possible estimates of variable values for each <br /> <br /> <br />study case. <br /> <br />Table A. Simplified Dam Break Model Input Variables <br /> <br />Dam Crest Elevation (Top of Dam) <br /> <br /> <br />Final Breach Bottom Elevation <br /> <br /> <br />Reservoir Storage Volume <br /> <br /> <br />Reservoir Surface Area <br /> <br /> <br />Final Breach Width <br /> <br /> <br />Time Required for Breach Formation <br /> <br />Turbine / Spillway / Overtopping Flow (at time of failure) <br /> <br /> <br />Topwidth (distance between equal contours) vs. (contour) <br /> <br />Elevation data for one or more downstream river valley <br /> <br />cross-sections <br /> <br />Manning Roughness Cofficient (estimate for each given <br />cross-section) <br /> <br />Flood Depth (depth at which flooding becomes a problem) <br />at each cross-section <br /> <br />'" <br /> <br />Height of Valley Wall (required for routing through <br />canyons) <br /> <br />Channel Bottom Slope (required if only one downstream <br />cross-section given) <br /> <br />1-2 <br />