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<br />of conveyance seepage ancl deep percolation losses. Individual practices will <br />consist of canal ancl lateral lining to reduce seepage losses aud minimize deep <br />percolation by improved on-farm water management practices such as installa- <br />~ tian of accurate flow measurement devicest irrigation scheduling, and more <br />~ uniform water applications. Since salinity problems result from a combination <br />~ of both salt concentration sncl salt pickup effects, an integrated site-specific <br />QO combination of the above types of strategies is usually required. <br /> <br />."..', <br /> <br />Achieving high irrigation efficiencies and other improvecl irrigation <br />management practices are goals not only of water quality planners, but often <br />of inclividual irrigators snd irrigation organizations as well. King and Hanks <br />(1975) and Willarclson and Hanks (1976) discuss many of the effects of irriga- <br />, , tion management on irrigation return flows. The technologicsl solutions to <br />salinity prOblems are often .the solutions applicable to reclucing agricultural. <br />energy consumption, achieving higher farm production ancl higher profits. <br />. .'!mproving the physical aspects of the irrigation system, including structural <br />rehabilitation and redes:Lgnand 'instituting better management practices for.... ,... ..'0, <br />the operation of the water delivery system by irrigation scheduling, call <br />pe~iods, ancl limiting wastes, must be jointly considerecl in any program for <br />improving the efficiencies of irrigation. <br /> <br />~ !." <br /> <br />" <br /> <br />Institutional constraints may also contribute to the salinity of the <br />basin. For example, much of the irrigated agriculture in the Upper Colorado <br />River Basin is marginal ancl the income is often minimal or even negative. <br />However, many ranchers ancl farmers freely aclmit that the only reason they <br />maintain these lands in production is to meet forage production requirements <br />for government grazing leases. These regulations should perhaps be re-examined <br />in relation to salinity control programs. <br /> <br />'S <br /> <br />Another nonirrigation practice which contributes to the salinity via the <br />irrigation system is the c1iversion of water during the winter months for <br />livestock water purposes which is commonly practiced in many irrigated areas <br />in the Coloraclo River Basin, such as the Lower Gunnison and Price-San Rafael <br />drainages. This is an often necessary, simple solution to provide water for <br />cattle and sheep herds which winter in the lowlands, but this constant source <br />of canal seepage has a very marked effect on the waterlogging and salination <br />of lands below the canels. In the Lower Gunnison alone this practicecontrib- <br />utes as much as 75,000 Mgm per year. There is little doubt that alternative <br />supplies of livestock water woulcl recluce salt loadings from these areas. The <br />piping of livestock water shoulcl be incluclecl in salinity programs for regions <br />which require the use of water supplies for these purposes, because the ground- <br />waters are usually much too saline for even livestock use. <br /> <br />. <br /> <br />Within each basin grouping of salinity control alternatives, various <br />combinations of specific projects can be selected to accomplish the control <br />program goals. For the purpose of this case study, four groupings of agricul- <br />tural salinity control alternatives will be considerecl: (1) canal and ditch <br />lining; (2) lateral linings; (3) on-farm improvements; and (4) desalination of <br />return flows. These agricultural salinity control programs listed above are <br />not the only methoclologies applicable in the UCRB, but they are the currently <br />most accepted "Best Mansgement Practices" (BMPs) ancl will indicate the pr.oper <br />approach to a basin-wicle control program. Ho"Wever, a planner should not limit <br /> <br />.- <br /> <br />51 <br /> <br />"',:-,( <br /> <br />. <br /> <br />. . <br /> <br />'~! <br /> <br />'. <br />