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River for the "with fai1ure" conditions is shown on p1at.es 21 through 24. The spillway flow is basically confined to the S,md and Toll Gate Creek channels. However, the dam failure flows down Cherry Creek inundate a lllrge area outside the confines of the channel and would cau.se c:.Eltastrophic losses. These losses are discussed in detail in the economic portion of this report. PROBABLE MAXIMUM FLOOD ROUTING When the full PMF, with a peak discharge of 662,700 c. f. s, and a total volume of 359,200 acre.feet was routed through Cherry Creek Reservoir assuming the dam did not fail, the embankment crest at: elevation 56l.4. 5 was overtopped for 7,5 hours with a maximum depth of 4,2 feet, The depth of overtopping "'as greater t:han 1 foot for 5,25 hours, The inflow hydro graph , pool elevation, and outflow hydro graph for both the spillway and overtopping flows are shown on plate 25. The overtopping hydrograph, with a peak discharge of 35/,,300 c. f, s., was routed down Cherry Creek and the South Platte River using the lIarders routing model, The peak discharge, peak elevation. arrival time, and pealking time are shown in table 7. The spillway outflow hydro graph , 'wi t:h a peak discharge of 56,300 c, f, s " was routed down Sand and Toll Gate Creeks and the results are also displayed in table 7, DAMBRK was used to determine the outflow hydro graph when the full PMF was routed through Cherry Creek Reservoir assuming the dam would fail, The breach parameters described previously were used for this analysis. The dam was assumed to fail when the flow over the top of the dam was l/2-foot deep, elevation 5645.0 feet m.s.l. Failure of Cherry Creek Dam under these assumptions would produce a ravaging flood in the valley below the dam, The peak outflow would be approximately 2,0 million c. f, s, The peak spillway outflo'. would be about 53,100 c. f. s. The outflow hydrographs were reouted down both Sand and Toll Gate Creeks and Cherry Creek and the South Platte River. Table 7 shows the results of the routings for comparison to the "without fai.lure" flood routings. "Without failure" assumes the dam does not fail although overtopped by 4,2 feet, which is unlikely. The flood outlines for Ilwith" and I1without failure" conditions are shown on plates 26 through 28, With dam failure, peak elevations would be as much as 18 to 27 feet higher than without dam failure. 27