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• Brid e <br />An evaluation of the capability of the bridge spanning the Williams Fork <br />River to safely pass the 100-year flood was performed by Leonard Rice <br />Consulting Water Engineers, Inc. (LRCWE). The results of the evaluation <br />indicate that the bridge will safely pass the 100-year flood. <br />Their evacuation was based upon the following: 1) field survey data <br />taken June 15-16, 1981, 2)_ contour data from map IV-9, and 3) estimates <br />of the 100-year flow. The backwater computations performed demonstrated <br />the 100-year flood will be conveyed under the bridge with four feet of <br />clearance and an average velocity of 13 fps. <br /> <br />LRCWE provided a 100-year flood plain profile for the immediate area and <br />a cross section of the bridge. Both are included herein. The HEC-2 back- <br />water analysis program was used in their evaluation and this program is <br />included by reference. The computer printouts can be provided if necessary. <br />The magnitude of the 100-year flood was estimated considering available <br />gauged streamflow data and a publication titled "Manual for Estimating Flood <br />Characteristics of Natural-Flow Streams in Colorado" prepared by the <br />Colorado Water Conservation Board and the U.S.6.5. in 1976. <br /> <br />-317- <br />