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<br />exceedance flow is shown on Figure 9 in Appendix B. <br /> <br />Alternative 2. <br /> <br />General <br /> <br />Bypass Alternative 2 is very similar to Alternative 1 with the exception of the addition of <br /> <br />secondary screens and a pump-back structure. This system maintains the 44 cfs flow in the <br /> <br />bypass slot and then diverts 34 cfs through a set of secondary screens into a pump well where the <br /> <br />flow is pumped back to the canal below the fishscreens. The fishscreen structure's primary <br /> <br />screens can then be sized for a slightly reduced flow of 606 cfs ( the 640 cfs design flow minus <br /> <br />the 34 cfs secondary screen flow). This arrangement is shown on Figure 9 in Appendix B. The <br /> <br />secondary screens are designed as vertical traveling belt screens. This type of screen contains a <br /> <br />continuous belt made of screen mesh powered by a motor on the top deck. Any debris that <br /> <br />attaches to the belt is lifted up out of the water and sprayed off on the downstream side of the <br /> <br />belt. A photo of this type of secondary screen is shown on Photo 12 in Appendix A. The screens <br /> <br />are sized to meet the 0.5 fps approach velocity with a 34 cfs flow through the screens. Assuming <br /> <br />a minimum water surface elevation in the bypass downwell ofEl. 4676.5, two vertical traveling <br /> <br />belt screens are required. <br /> <br />The flow through the screen is maintained by pumps. For a 34 cfs flow, and assuming a <br /> <br />maximum pumping head of about 5 .0 feet, two 25 hp pumps are required. <br /> <br />26 <br /> <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 />