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The emergency spillways for Ponds A, A and C will be directed <br />toward Plann Draw. The emergency spillway for Pond H is <br />directed toward Pond C. ,~ typical spillway section is shown <br />on Plate 29 entitled Emergency Spillway Detail. <br />Actual weir crest length calculations resulted in values <br />ranginS between 10 and 35 feet to pass the required 25-year <br />storm event. Plate 30 entitled Emergency Spillway Rating <br />Curves, shows the discharge rating curves for various crest <br />Length emergency spillways. Actual crest lengths are <br />tabulated on the Pond Schedule (Plate 22 1. <br />The 25-year peak discharge from the inflow design flood was <br />used in the computations to size the emergency spillway weir <br />lengths without regard to the attenuation of inflow that the <br />• reservoir, toge_her c.•ith its primary spillway, will achieve. <br />This provides added c•~nscrvatism to the spillway design and <br />to the safety of the ponds. The attenuation of the 25-year <br />peak discharge at Pond H, however, was considered in sizing <br />the spille;av for Pond C. The emergency spillways will be <br />constructed over the tops of the embankments and will be <br />provided c.-ith 18 inches of 12-inch riprap over a 6-inch <br />gravel blanket, from the embankment crest to 10-feet <br />downstream of the embankment toe area. <br />ENERGY DISSIP?.TORS <br />Riprap energy dissipators will he provided at the outlet ends <br />of all primary outlet works. Plate 31 illustrates a typical <br />primary spillway energy dissipator, utilizing 18 inches of <br />12-inch riprap over a h-inch gravel blanket. <br />i • <br />