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The advantage of louvers over screens is their simplicity. The louver system requires no moving mechanical parts or equipment. In addition to the decision oflouvers vs. screens, a selection of the bypass alternative is required. This decision may come down to the availability of bypass flow. If the additional bypass flow is available, Alternative 1 appears more favorable because of the added capital and operation and maintenance costs associated with the vertical traveling belt screens and pumps used with Alternative 2. Preferred Option General After consideration of the five screening options and two bypass options presented in this memorandum, the recommended preferred option is to use fishscreen Option A and bypass Alternative 1. A screen is selected over louvers because the screen will provide complete exclusion of all fish from the canal. A louver is not completely effective, particularly for juveniles, at preventing fish from entering the canal. Option E, the vertical flat plate in the river, was not selected because of it's high cost and because of uncertainties in it's hydraulic flow distribution and concerns over high sediment and debris loads in the river. For Option B, the vertical flat plate screens in a V -configuration, it was felt that the V -configuration would be more difficult to remove sediment from the interior of the V, than from a single row of screens. Option A was selected over Option C, because vertical flat plate screens and the associated 28 I I I I I I I I I I I I I I I I I I I