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<br />111-2 <br /> <br />I <br />I <br />I' <br />I <br />I <br />I I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br /> <br />State University and presented to U.D. & F.C.D. during August 1975. <br />The data were accepted for use by U.D. & F.C.D. in the summer of 1975. <br />To determine the impact of the new criteria on the Hidden Lake <br />analysis, the new procedure was used to determine the inflow hydro- <br />graph for Hidden Lake and was compared to the results of the Phase A <br />analysis. The peak flows were found to be shifted downstream in time <br />by about five minutes and were increased by about one percent. Since <br />the hydrology was based on a five-minute calculation interval, the five- <br />minute time peak shift is not entirely due to the change in procedure <br />for determining the unit hydrograph. Therefore, the methodology was <br />considered to have a negligable effect on the design flows for Phase <br />B and the Phase A hydrology was not revised to reflect the methodology <br />change. <br />C. Flood Routing <br />The flood routing procedures used for the Phase A analysis include <br />channel routing, reservoir routing and hydrograph separation procedures <br />for special application of flow splitting (separation of channel). <br />The results of the flood routing for the existing and future develop- <br />ment conditions with existing drainage facilities are presented in <br />Tables 111-4 and 111-5 as design flow values (refer to Sheet 2 of 17, <br />Volume II for location of design pOints). Hydrographs for the future <br />development condition with existing drainage facilities were presented <br />in the Phase A report along with a discussion of the flood routing <br />procedures. <br />