CIV E 530 - OPEN-CHANNEL HYDRAULICS SPRING 2005 HOMEWORK No. 9 (100 percent) Determine the crest elevation and the shape of an overflow-spillway section having a vertical upstream face and a crest length of 200 ft. The design discharge is 65,000 cfs. The upstream water surface at design discharge is at Elev. 750 ft, and the average channel floor is at Elev. 650. (See Fig. 14-5 of text for reference). Plot the overflow-spillway section to an appropriate scale.