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. :'(~~.~ ~~~~ Spillway The spillway is an uncontrolled type with a capacity of 27,600 c.f.s. at the maximum water surface of 4447.0 feet. The upstream transition has vertical wingwalls and a concrete apron that extends 50 feet upstream from the toe of the overflow section. The overflow section is an ogee crest 100 feet long with a weir height of about 43.5 feet and the crest set at elevation 4428.5 feet. Relocated State Highway 144 will pass over the spillway overflow section on a 30 foot wide concrete bridge. Spills over the weir are carried to the stilling basin below the dam in a 100 foot wide open concrete chute. The concrete stilling basin is designed to serve both the spillway and river outlet works. Exhibit 5 shows the location and details of the spillway. . In the design a surcharge of approximately 576,000 acre-feet plus 384,000 acre-feet exclusive flood control capacity in combina- tion with a spillway discharge of 27,600 c.f.s. and a river outlet discharge of 8,600 c.f.s. was provided to protect against the inflow design flood which has a peak of 344,000 c.f.s. and a 20-day volume of 1,363,000 acre-feet. The river outlet discharge was limited to 5,000 c.f.s. during filling of the flood control capacity. Subse- quent to the design of the spillway, reservoir allocations were adjusted to allow 475,000 acre-feet for exclusive flood control and 75,000 acre-feet for joint use of flood control and irrigation. Adjustment to the spillway capacity would be minor and the design was not changed. River Outlet Works The river outlet works is near the left abutment of the dam and to the right of the spillway. It will serve two purposes. During periods of flooding, the outlet works will have capacity to discharge 8,600 c.f.s. with the reservoir water surface at the maximum elevation of 4447.0 feet and will be used along with the spillway to protect the dam. During periods of normal operation, the outlet works will be used to make releases to the river for downstream irrigators and for by-passes as required. . The river outlet, as shown on exhibit 5, will consist of an inlet structure with a trash rack, two 10-foot diameter concrete circular conduits extending from the intake to a shaft and gate structure housing two high pressure slide gates, and two 10-foot diameter steel pipes inside two 14-foot diameter concrete horseshoe conduits terminating at a control house. Both of the steel con- duits will be provided with high pressure slide gates at the discharge end to regulate outflow from the reservoir into the river. Water from this outlet will pass into the same stilling basin used for the spillway. 21