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<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 /> <br />- 7 - <br /> <br />cost analysis, but is useful for comparison purposes. <br /> <br />Floodplains are delineated on topographic maps in the <br /> <br />hydraulic analysis part of the drainage study. The benefit- <br /> <br />cost analysis will require estimates of the depths, lateral <br /> <br />limits and velocities of the flooding. Appropriate backwater <br /> <br />techniques should be utilized, and consideration should be <br /> <br />given to the effects of reservoir and channel routing. <br /> <br />Formulation of Alternatives <br /> <br />Once the magnitude of the flooding problem is defined, <br /> <br />specific alternatives are formulated to accommodate the design <br /> <br />flows and reduce flood damages. The engineer should be aware <br /> <br />of the effect that each alternative will have on the flood <br /> <br />hydrology. After the number of alternatives has been narrowed <br /> <br />to a select few, another iteration of the flood hydrology should <br /> <br />be accomplished to insure that any proposed facilities will be <br /> <br />adequately sized. <br /> <br />The benefit-cost analysis will evaluate the effectiveness <br /> <br />of the various flood control alternatives. <br /> <br />Benefit-Cost Methodoloqy <br /> <br />The following benefit-cost methodology is recommended for <br /> <br />use in urban flood control projects until a more refined method- <br /> <br />ology is developed. An example is given to help explain the <br /> <br />steps. <br /> <br />~LeonardRiceconsultingWaterEngineerSlnc. <br />