Laserfiche WebLink
<br />V, Resource Impacts of Water Salvage <br /> <br />When the efficiency of water used for any purpose is improved there are resulting <br />changes to stream flows, depletions, and return flows, Changes potentially effect both the <br />quantity and timing of water in the stream system, When a water right is transferred similar <br />changes occur, but the "no-injury" rule has a counter balancing tendency to preserve stream <br />conditions, at least to the extent other appropriators can demonstrate reliance on those <br />conditions, Changes in the stream system result in a variety of related environmental <br />impacts, <br /> <br />A. Water Supply Impacts <br /> <br />In an efficiency improvement project some combination of incidental consumptive uses <br />and return flows will change in response to the typical mix of activities. The following <br />discussion considers those changes separately to illustrate discrete impacts, <br /> <br />When incidental consumptive use is reduced by efficiency improvements depletions are <br />reduced resulting in a gain, or accretion to the net available water supply in the basin, How <br />that increased supply gets used depends on the hydrology of the particular basin, the <br />location in the basin where the efficiency improves, demands for water, the distribution of <br />water rights in the basin, and interpretations of water law, The increased supply might be <br />picked up by the original diverter to meet new or existing needs, by other appropriators <br />above or below the location of the improvements, or may flow downstream if there is no <br />current demand for this new increment of water. While it is not possible to identify in <br />absolute terms the final fate of a particular accretion to the basin supply, it is clear that any <br />reduction in depletions by one user leaves more water in the stream for other users. <br /> <br />When an efficiency improvement reduces return flows the effect on the stream system, <br />is even less clear, Return flows can be reduced as a result of increased consumptive use (if <br />allowed) or lower water diversions made possible by reduction of conveyance and on-farm <br />losses. If consumptive uses (either productive or inCidental) are not reduced there will be <br />no change in depletions and no gain to the basin water supply. In a basin which already has <br />sufficient water to meet all potential depletions at any location there would be no impact <br />on available supplies from reducing return flows, However, there can be significant impacts <br />on the available water supply as a result of changing diversion rates and patterns in a basin <br />where demand outstrips supply, <br /> <br />If a senior irrigator who historically has called out junior users to make its diversions <br />becomes able to meet its needs with less water, then upstream juniors who previously had <br />to bypass water to meet the senior's call will experience an increase in their available supply, <br />If those juniors divert this water upstream depletions may be increased, causing a <br />corresponding decrease in the available water supply downstream of those juniors, If other <br />downstream users have sufficiently senior rights, they may continue to call the saved water <br />past upstream users. Note that the no injury rule only applies when a water right is <br /> <br />19 <br />