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.~ Exhibit 73-7A for location and design of 18-inch diameter corrugated metal pipe spillways. (CMP) with a The principal spi lluay consis s trash rack et the inlet. This of an pipe 1914 iS ill keep the pond level at the 7086.3 elevation. Maximum elevation (pea stage) above aogfi th principal spi lluay with the passage at the 70-yea r, 24-hour event uil be 7086.8, this leev 2.8 feet to the emergency spillwa y. The emban went portion of the emergency spillway was underlayed wi h e geotextile as shown on Exhibit 3-7A. Riprap will be used to protect the channel the event of a discharge through the s 'llway. The emergency spit ay outflow channel conai sts of e v getated, trapezoidal channel. In order to protect the hannel, in the unlikely even of a discharge prior to vegetation establishment, the cha L will be meek enically abilized. This was conducted in the following manner. The she el will be shaped t the design geometry (see Table 73-15-7). The channel was seeded with combination intermediate wheatgrass, tell fescue end basin wildrye. This aced mix wi l provide a long term erosion control (see Addendum C). In order to provide erosional st ilit prior fo vegetation establishment, a product • tailed Lendatrand wee applied to the s dad area. Landstrend roving fibers are continuous fibri laced polypropylene strands ep Ted ith the aid of an air compressor end applicator gun et a rate of 0.25 to 0.35 lb /sy. Thes fibers are then tacked together end to the surface by spreyi ng pine ter ( edOyl) or asphe emulsion on the fibers. Tests conducted on Lendatrand/ROedOyl end Le strand/Asphalt Emu is n indicate that the application, prior to vegetation esteblishme can withstand velotitie up to 9 FPS. The application rate will be about 0.25 gall ns per square yard for RoedOyl nd about 0.35 gallons per square yard for asphalt emul ion. The channel was designed with the aid of the BEOCAO+ comp ter program. The closest vegetation typ listed in SEDLAD+ resembling the species list above is tell fescue. Stability en capacity for this grass type is listed es B. As ate d earlier, prior to a "good sta of grass," the Landstrend wilt protect the channel du 'ng passage of the 25-year, 24-hour pr~ 'pitetion event. Peak stage elevation with the passage of the ~0 3 25-yea storm is 7090.4, this leaves 2.8 feet of freeboard to the top f embankment. Plea a refer to Addendums A and B for capacities of both spillways during pas age of the 70 and 25•yeer storm events. Table 13-SA-7 end Addendum C presents the design d\ails for • / he principal and emergency spillway. 13-SA-9