Laserfiche WebLink
similar to that of the South Columbia Basin Irrigation District. Meet with landowners on a <br /> regular basis to inform them of the progress of all phases of the study and to obtain their <br /> recommendations. <br /> Phase II Tasks <br /> Task 7 <br /> Utilizing the drainage inventory conducted in Phase I,along with the cleaning of one small drainage <br /> system,complete the benefit/cost analysis of system-wide rehabilitation,utilizing the U.S.Bureau of <br /> Reclamation's economic analysis guidelines for drainage systems.14 Such benefit/cost analysis <br /> incorporates information on land class,the amount of acres to be drained, and estimated capitalized direct <br /> net benefit per acre. The land class usually determines the dollar value of capitalized direct net benefit <br /> per acre. This benefit/cost ratio analysis would be performed for three scenarios: <br /> a. Rehabilitation. Rehabilitation of the existing drainage system layout and lands served, <br /> with only cleaning and selected improvements to existing drainage system features. This <br /> would include replacement of existing drains where it is clearly needed,replacement of <br /> all existing manholes,re-excavating of the surface drainage system where clearly needed, <br /> and installation of drainage pumps for closed basins. <br /> b. Replacement. Rehabilitation of the existing drainage system layout and lands served, <br /> replacing all subsurface drains,installing manholes as needed under new design criteria, <br /> re-excavating all surface drains/wasteways, and installation of drainage pumps for closed <br /> basins. <br /> c. Re-design. Complete re-design and installation of a new Lower Arkansas Valley <br /> drainage system,including additional lands to be served by the drainage system,utilizing <br /> new information on water contours and the hydrologic conductivity of soils. <br /> Re-design would include a new drain system layout based on an updated <br /> understanding of the hydrologic conductivity of soils,the required spacing of drains,and <br /> whatever depth of the drainage system is needed for current and anticipated crop <br /> production in the Lower Arkansas Valley. <br /> d. A benefit-cost analysis that discounts the benefits and costs to present value will be <br /> undertaken. Appropriate life expectancies of three rehabilitation scenarios will be <br /> determined.The output of the analysis will take the form of a benefit-cost ratio of the <br /> three scenarios in the context of present value. A critical and careful analysis of the costs <br /> will be performed: engineering,installation, operating and maintenance.The benefits will <br /> be analyzed by ascertaining the ongoing benefits to the different classes of land under the <br /> project. <br /> Most economic analysis and decision making fails to take into account <br /> uncertainty. However,many of the components of feasibility analyses of projects are <br /> subject to the inability to predict what will happen in the future with certainty. Rather <br /> 14 Part of this economic analysis will be informed by traditional U.S.Bureau of Reclamation methodology. See, <br /> Drainage Manual:A Water Resources Technical Publication. Bureau of Reclamation,U.S.Department of Interior <br /> (1993). <br /> 16 <br />