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ARKANSAS VALLEY DRAINAGE STUDY <br /> SCOPE OF WORK <br /> The study will be conducted in two phases,and completed in three years. The beginning <br /> of Year 1 is designated as July 1,2005,the date that the Colorado Water Conservation Board <br /> grant is to come into effect. A few tasks commenced in late 2004, due to the authorization given <br /> by CWCB to use matching funds provided by other participants to the project. <br /> An interim report to CWCB and other participants in the project will be provided at the <br /> end of Year 1 instead of Year 2,as was indicated in the original proposal. A final report will be <br /> provided to CWCB at the end of Year 2 instead of Year 3,as also indicated in the original <br /> proposal. A supplemental report will be provided at the end of Year 3,following a third <br /> irrigation season of monitoring the beta site(s). <br /> Phase I will involve: (1)GPS/GIS mapping of the current Lower Arkansas Valley buried <br /> tile and surface drainage system as it is known and/or can be identified through fieldwork,and <br /> establishing a drain unit numerical identification system to provide the capability for a more <br /> systematic maintenance of the drainage system. This will be followed by(2)a thorough cleaning <br /> of one of the smaller older subsurface and surface drainage district systems(beta) system in the <br /> Lower Arkansas Valley. Other activities in Phase I include a study tour and workshops for <br /> drainage district representatives, for the purpose of exploring possible consolidation of the 25 <br /> plus drainage districts in the lower Arkansas Valley. <br /> Phase I mapping and cleaning activities will: (a)provide information and experience <br /> needed to estimate the per mile cost of rehabilitating the entire subsurface and surface drainage <br /> system in the Lower Arkansas Valley under three different economic scenarios(discussed <br /> below), (b)provide information on potential changes in the drainage patterns as a result of <br /> drainage system rehabilitation(i.e.,through the cleaning of the beta system)and, (c)provide data <br /> to calculate the estimated benefit/cost ratio for the three different rehabilitation scenarios. <br /> Phase II will involve completing the mapping of the drainage systems,compiling data on <br /> changes in the drainage of lands resulting from the cleaning of the beta system,completing the <br /> benefit/cost analysis for three scenarios of rehabilitation,conceptualizing an annual Operations& <br /> Maintenance(0&M)plan for the four county drainage system,including possible initiatives to <br /> consolidate some 25-plus drainage districts in the lower Arkansas Valley. <br /> Phase I Tasks <br /> 1. Conduct a hydrologic study of the pattern of agricultural drainage and its affect on towns <br /> located in the irrigated areas of the valley. <br /> 2. Develop a GPS/GIS base map of the drainage systems. Inventory and describe all known <br /> and/or visible features of the subsurface and surface drainage networks in Otero,Bent, <br /> Prowers and Crowley counties. <br /> 3. Identify and prepare the beta drainage system. <br /> a. Select beta drainage system. <br />