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<br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br /> <br />VIII. RECOMMENDED ALTERNATIVE AND ECONOMIC EVALUATION <br /> <br />A. Recommended Alternative <br /> <br />Spi 11 way Al ternat i ve No. 2 is recommended for construct i on for <br />severa 1 reasons. The fi rst bei ng the tota 1 cost of construct ion is <br />less with this alternative than with Alternative No.1. Also, the <br />capacity of the outlet works is increased significantly, as is indi- <br />cated by the two capacity curves shown on Figure A-4 in Appendix A. <br />The need for erosion protection with riprap will probably be less with <br />A lternat i ve No.2, as there is exposed bedrock in the mai n channel <br />below the outlet works. <br /> <br />The recommended Alternative No.2 will consist of the following: <br /> <br />1. Removal of existing spillway. <br /> <br />2. Construction of french drain along bottom of existing <br />spillway channel. <br /> <br />3. Backfill of existing spillway and spillway channel to <br />stabilize the slide area. <br /> <br />4. Construction of an emergency spillway near the existing <br />spillway. <br /> <br />5. Removal of portion of outlet conduit. <br /> <br />6. Construction of service spillway near the existing outlet <br />condu it. <br /> <br />- VIII-l - <br />