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<br />0'''-3'' <br />l. &. ,." I <br /> <br />II Description and Definition of Water Salvage <br /> <br />Water salvage generally connotes a scheme where irrigation water use is reduced by. <br />using more efficient delivery and application methods. Salvage measures usually involve <br />recovery, transfer, and use elsewhere of the water made available by the reduced irrigation <br />use. Recent salvage bills provided that the original irrigator would retain the legal rights, <br />including the priority date, for some portion of the recovered water, and allowed sale of it <br />as an incentive to make the improvements to his delivery system. <br /> <br />Much of the debate over water salvage indicates that imprecise use of terminology <br />creates needless confusion and often obscures the real policy considerations. A better <br />evaluation of the role of salvage will be fostered by the use of consistent language and an <br />understanding of the hydrologic cycle (see Figure 1). An irrigation water budget which <br />identifies and quantifies water in the various stages as it passes through the hydrologic cycle <br />is a useful tool to illustrate the terminology and physical processes related to irrigation water. <br /> <br />use. <br /> <br />A. Irrigation Water Budget <br /> <br />Examples of water use from a typical unimproved and improved irrigation system are <br />shown in Figures 2A and 2B. Water in its various locations can be quantified and tracked <br />on a daily, weekly, monthly, or annual basis. A tabular quantification of an annual water <br />budget for tbe illustrated system is shown in Table 1. A water budget becomes more <br />complex if done on a short term basis because water moves through different parts of the <br />system at different rates. Generally, water is stored in the soil and groundwater systems <br />while stream diversions are taking place, and then returns to the stream from ground storage <br />much later in the season. In certain large systems diversions occur several days prior to <br />farm deliveries because of the transit time required to move water through the canal and <br />ditch system. With sufficient information about the ditch, soil, and groundwater systems <br /> <br />3 <br />