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Section 3 Alternative Agricultural Water Transfer Methods to Traditional Purchase and Transfer 3.11 Opportunities for Agricultural Efficiency Improvements The evaluation of the potential for agricultural efficiency measures to address future water supply needs was originally assigned to the Water Conservation and Efficiency TRT. Due to lack of participation, this section was prepared without the input of the TRT and will now serve as an opportunity for statewide dialogue. 3.11.1 Agricultural Efficiency Measures Agricultural conservation or agricultural efficiency implementation as a means to create new water supply must be carefully evaluated because the issue is very complex. These measures may involve increasing the efficiency of water used for irrigation, so that more of the water that is diverted from streams and rivers or pumped from groundwater meets the direct CU needs for agricultural crops. Typical agricultural efficiency measures include canal lining or the conversion of irrigation practices and technology from flood irrigation to gated pipe or the installation of sprinklers or drip irrigation systems. These measures are designed to reduce the delivery losses that occur as water is diverted from a stream or as groundwater is pumped and delivered to the farm or ranch or as it is applied to the crops. The opportunity to produce a water supply for additional or new uses in response to these efficiency measures are limited to situations where so called "losses" are not contributing to another users water rights and/or compact obligations. Consequently, the opportunities to produce water supply are extremely limited. Nevertheless, there are select locations and situations that should be explored. The benefits of agricultural efficiency measures include: ~ No new diversions are required from rivers or streams. ~ Permits are not required for implementation. ~~ ~ Increased ability to deliver water to the crops can stretch existing supplies. This benefit would apply to water short irrigators that would benefit if additional water could be delivered to their crops. If the irrigator that has water short crops typically experienced 50 percent losses, reducing those losses will result in an increased delivery to the water short crops and a resulting increase in crop CU and decrease in return flows. ~ Agricultural efficiency may reduce non-crop CU. Some of the CUs and losses may be due to tailwater from irrigation ponding at the end of fields perhaps creating intermittent wetlands and evaporating, rather than returning as surface or groundwater return flows. ~ There may be potential water quality benefits. Canal seepage and/or flood or furrow irrigation may result in the leaching of minerals from the soils that result in impacts to the water quality of the return flows. Lining canals or the installing sprinklers may reduce the leaching of these minerals. This must be examined on asite- specific basis, as some irrigated fields may require periodic flushing of salts and minerals that accumulate in the soils in order to remain productive. The benefits of these improvements accrue to many, and programs like the Colorado River Salinity Control Program exist to encourage these types of improvements. There are a number of potential issues and conflicts that must be evaluated for the potential implementation of agricultural efficiency measures. ~ Historical agricultural return flows are a vital part of the flows in all basins and downstream surface water diverters and downstream states have relied on these return flows. ~ These return flows, in addition to satisfying downstreamwaterrfghts, also create delayed flows that can have instream and riparian environmental benefits and maintain aquifers for domestic and irrigation wells. ~ Typically, any water that is saved by efficiency measures such as canal lining or the conversion of irrigation practices and technology from flooding FINAL DRAFT 3-37