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<br />I <br />I <br />I <br />I <br />I <br />I <br />t <br />I <br />t <br />I <br />, <br />I <br />I <br />I <br />I <br />I, <br />., <br />I <br />I <br /> <br />A. <br /> <br />CHAPTER V <br />EVALUATION OF ALTERNATIVES AND <br />SELECTION OF MOST COST-EFFECTIVE SYSTEM <br /> <br />INTRODUCTION <br /> <br />1. Purpose and Scope <br /> <br />The purpose of this chapter is to review and evaluate alternatives for <br />upgrading the Mutual Mesa Ditch. The goal is to select the alternative <br />which will be most cost-effective. The project has been reviewed by, and <br />is eligible for funding from two Federal agencies (NRCS and Bureau of <br />Reclamation), and one State agency (CWCB). Each agency has different <br />criteria for review of alternatives, and a different approach for determining <br />if the project is cost effective. The primary goal (with respect to this <br />project) of NRCS and BuRec is salinity control and their criteria is keyed <br />to that goal. The primary goal of CWCB is to develop the raw water <br />resources of the State, either by increasing efficiency of or expanding an <br />existing project, or construction of new projects. The approach taken by <br />each entity with regard to the Mutual Mesa Lateral improvements is <br />described in this chapter. <br /> <br />2. Description of Existing Mutual Mesa Ditch <br /> <br />The Mutual Mesa Ditch connects into Orchard Mesa Canal No. 1 about <br />one-half east of the intersection of A 1/2 and 29 1/2 Roads (Figure Ill-B). <br />It trends in a northwesterly ditection across the west end of Orchard Mesa <br />until it terminates approximately 1/2 mile west of Orchard Mesa Middle <br />School, adjacent to the Colorado River. Part of the ditch is on the public <br />road right-of-way, and part of it is in ditch right-of-way across fields or on <br />strips of land between housing developments. It crosses under several <br />roadways and water courses. Several short sections are in pipelines where <br />the ditch crosses roads, ditches or sidewalks. <br /> <br />The estimated capacity of the existing ditch is 28 cfs at its upper end. For <br />the first 1700 feet, it is a mOderately large ditch, 16 foot wide across the <br />top and about 4 feet deep, with a trapezoidal cross section. The cross <br />section gradually grows smaller as water is diverted. Near the bottom end, <br />the ditch is 6 feet wide and about 2 1/2 feet deep. There are over 90 <br />headgates on the ditch and a number of trash racks and small concrete <br />structures. <br /> <br />V-I <br />