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<br />Comments to SWSJ, November 3t 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 aJso that since 80 percent or more consumptive use of Western water is <br />by agriculture. as often noted it wourd only take a fraction of that to be a significant increase in <br />urban supply, One of the goars of taking this seriousty 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 conditjons dependent on the status quo. <br /> <br />Step 1 of The Irrigation Efficiency Problem: Simplest possible case~ <br /> <br />Consider 100 acres being irrigated with 100 units of water. The technjque is furrow irrigation with <br />open ditoh and the return frow from the diversion and application of 100 units of water ;s 50 units <br />(50o/Q efficiency of use, or ..field efficiency"..) The Arkansas River Water Bank Pilot Program <br />(WSPP) affows transfer only of stored water, $0 the example wUI start with that. <br /> <br />Suppose for sjmplicity that this field is getting 75 units of djrect flow, and 25 units of stored water. <br />The 25 are eligibre for the WBPP. Because the return flow has been established for this purpose <br />to be 50 percent, by the State Engineer, 12.5 units can be transferred UawayJl, 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 appUed to 75 acres, in the same way as beforet and there will be 37.5 units <br />consumptively used, and 37.5 will be return flow+ <br /> <br />So far: the farmer has presumably received money from transfer of 12..5, and return flow is still <br />50. (For simplicity, please overlook the internal workings of ditch and canal companies right now.) <br />This is least controversial if the acreage irrigated is reduced; "dry_upU of 25 acres is requfred~ So <br />fart in the Arkansast one of the objections to the WBPP is that there is no funding for enforcement <br />of Idry..Up", 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 should. <br />Without the requirement~ the farmer coufd spread the remaining 75 units of water on the 100 units <br />of Jandt and the return flow would be less than it ushould.. be, since more of the 75 unlts of water <br />would evaporate or be consumed by the crop. The farmers efficiency of use would be greater, <br />but the downstream would lose water. <br /> <br />UDry-up", the requirement of non-use of a proportional area of farm landt is the simplest way to <br />assure that there is no increase in consumptive use. Unfortunately, requiring dry-up requires <br />rasing all production from 25 acres, losing or affecting some soil fertUity 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 since management has not changed. The focar 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 seff~enforcement is not crediblet given the strength of incentives <br />to cheat. <br /> <br />A note: if the land taken out of production was not yielding enough to at least lIbreak evenu, it <br />would be taken out in any case. SOt without some other change, this reduces production. If the <br />dry..up requirement is imposed. it would seem also to require taking fairly observable areas out of <br />production, in contiguous pieces. rf 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 />arbitrarily specified. But if the lowest-yielding soils were taken out of production, the shapes and <br />pieces of land might reflect contours or underlying 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 soils, especially alfalfa fieJds 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~ Designatfon of those fields as ''temporary dry up" would not <br />reduce yield nor consumptive use; thereby injuring downstream users~) SOt the way Udry up'. is <br />