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<br />Comments to SWSI. November 3,2003, by John Wiener <br /> <br />26 <br /> <br />supported management changes for decades, but there is an important gap between the theory <br />and the practice~ Note also that since 80 percent or more consumptive use of Western water is <br />by agriculturet as often noted it would only take a fraction of that to be a significant increase in <br />urban supply. One of the goals of taking this seriously is learn how a few percent here and there <br />from many farms could be aggregated effectively to make that supply, without creating sudden <br />and injurious changes in conditions dependent on the status quo. <br /> <br />Step 1 of The Irrigation Efficiency Problem: Simplest possible case4 <br />Consider 100 acres being irrigated with 100 units of water. The technique is furrow irrigation with <br />open ditch and the return flow from the diversion and application of 100 units of water is 50 units <br />(50ok. efficiency of use, or IIfield efficiencyu.) The Arkansas River Water Bank Pilot Program <br />(WBPP) aUows transfer only of stored water. so the example will start with that <br /> <br />Suppose for simplicity that this field is getting 75 units of direct flowt and 25 units of stored water. <br />The 25 are eligible for the WBPP. Because the return flow has been established for this purpose <br />to be 50 percent, by the State Engineert 12.5 units can be transferred ~.away." and 12.5 are <br />administered to maintain the pattern of volume and timing of return flow. The 75 units of direct <br />flow can be applied to 75 acres, in the same way as before, and there win be 37.5 units <br />consumptively used, and 37.5 wur be return flow. <br /> <br />So far: the farmer has presumably received money from transfer of 12.5, and return flow is stHI <br />50~ (For simplicity, please overlook the internal workings of ditch and canal companies right now.) <br />Thjs is least controversial if the acreage irrigated is reduced; Jldry_upU of 25 acres is required. So <br />farJ in the Arkansast one of the objections to the WBPP is that there is no funding for enforcement <br />of .tdry-up" t and some farmers think this is the only fair way to operate the program. The statute <br />establishing the pilot program does no require dry-up. but many leading farmers think it shourd. <br />Without the requirement, the farmer could spread the remaining 75 units of water on the 100 units <br />of land, and the return flow wouJd be less than jt nshouldu be, since more of the 75 units of water <br />would evaporate or be consumed by the crop. The farmer.s efficiency of use would be greater, <br />but the downstream would rose water. <br /> <br />.-Dry-uptt. the requirement of non..use of a proportional area of farm land, is the simplest way to <br />assure that there is no increase in consumptive use. Unfortunately, requiring dry...up requires <br />losing all production from 25 acres. losing or affecting some soU fertility characteristics, affecting <br />use or demand for farm labor. and affecting weed control and erosion. Arso, the 75 acres is not <br />giving a higher yieldt sJnce management has not changed. The focal economy is affected by <br />reduced production" <br /> <br />Enforcement of dry-up also requires some effort by someone at some expense; can this be <br />avoided? Many farmers feel that self-enforcement is not credible, given the strength of incentives <br />to cheat. <br /> <br />A note: if the rand taken out of production was not yield ing enough to at least IIbreak even II; it <br />would be taken out in any case, So~ without some other change, this reduces production. If the <br />dry-up requirement is imposed~ it would seem also to require taking fairry observable areas out of <br />production, in contiguous pieces. If the amount taken out of production was in corner areas not <br />reached by center pivots. this might have less negative effect than if the dry-up area was more <br />arbitrarify specified. But if the lowest..yieldfng soils were taken out of production, the shapes and <br />pieces of land might reflect contours or underrying soils and subsoils. That might be most <br />beneficial for the farmer. but hardest to monitor. (You would also see farmers designating some <br />of their best producing soiJst especially alfalfa fields that are drinking from the groundwater. We <br />have many fields that, once established, require no irrigation - although they have a water right <br />and are considered to be irrigated. Designation of those fields as "temporary dry up" would not <br />reduce yfeJd nor consumptive use~ thereby injuring downstream users.) So, the way "dry up.. is <br />