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Show PART IV FUTURE DEMAND subsurface drainage costs are higher, particularity so in the San Juan- Colorado Subregion where diverse cropping requires more stringent ground water control. Requirements for providing project drainage on 176,300 acres of drainage-deficient potentially irrigable land to be developed for irriga- tion in the region by I98O, 2000, and 2020 are shown in Table kl. Ap- proximately 420 miles of these subsurface drains will be required at a total installation cost of about $11 million. This averages about $60 per acre of drainage-deficient new land to be developed by 2020. It is anticipated that about one-half of the deep drains required will be tile drains and the remainder will be open drains to serve several farms and provide outlet channels for closer spaced and generally shallower on-farm drains. Projections of Irrigation Costs Summary Irrigation installation costs in the region, exclusive of drainage costs, will total approximately $757 million by 2020.~U These include non-Federal and Federal costs. Non-Federal developments and on-farm costs include Federal participation on a cost-sharing basis. Federal develop- ments consist of two parts: (l) specific-use costs definitely tied to ir- rigation and (2) irrigation's prorated share of joint-use costs of major multipurpose facilities which include some non-Federal costs of privately developed multipurpose facilities. These various categories are illus- trated in the figure on page 86 and discussed in the sections that follow. On-farm costs On-farm development costs for new land projected for irrigation de- velopment by the year 2020 are approximately $^3*30^,^00 for the region. These installation and annual operation, maintenance, and replacement costs are listed in Table h2 and are based on projected acreage of land requiring brush and rock clearing followed by leveling and smoothing, miles of canal and ditch construction, and a number of water control struc tures (exclusive of on-farm drainage). About half of these on-farm irri- gation developments will generally be funded by the Federal Government and half by the landowners. yTotal installation costs for the Upper Colorado Region for irri- gation system improvement, drainage, and irrigation's prorated share of storage and major distribution systems is $857 million for an irrigated acreage of 2.1 million acres of land in 2020. 85 |