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VI-7 THREE ALTERNATIVES DESIGNATED From these eight alternatives, three were identified for detai led analysis as the result of a meetIng with t~. local entities, on December 5, 1973. Table VI-l presents a tabulation of the approxi- mate cost estimates of the eight schemes" TABLE VI-l Approximate Estimate of Alternatives (Millions of Dollars) Alternative Cost Deep Tunne 1 Surface Conduit tined Channel Unimproved Flood Plain Grass-Lined Channel Estimated Optimum Combination Improved Flood Plain Detention Pond 10.7 9.2 8.5 8.2 6.~, 5.0 ~.3 4.2 Note that these figures do not reflect many of the minute details and thei r costs but do provide a reI iable comparison for determining the better alternative schemes. The alternatives chosen,with the desires of local entities considered,corresponded to the relative best cost figures. The a 1 ternat I ves des i gnated fo r fu rther deta i led resea rch were the grass-l ined channel, the estimated optimum combination and the improved flood plain. The detention pond alternative, a variation of the improved flood plain alternative, was not specifically desig.. nated. This decisIon was made because this al ternative provides addi- tional benefits only to the trailer courts and thus would be less than optimal in a basin-wide reference frame. This scheme is reflected in the combination alternate where the land owners help with the cost of the channel improvements and detention storage directly attributable to alleviation of flooding created by their abuse of the channel. The other alternatives were el iminated because of theln higher costs and other additional variables which could only raise the cost. The deep tunnel and surface conduit alternatives also have operation and maintenance aspects that are somewhat unpredictable. Wheat'Rhi!lle ex- pressed some Interest In the surface conduit alternative, as a portion of the reach Is al ready being partially handled by a conduit. The im- plementation of a conduit for this reach wa!; reconsidered, but the ini- tial decision was only more clearly illustrated to be correct. There are many reasons besides the basically higher cost, such as: