2008-03-28_REVISION - C1981008 (3)

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03/31/2008 13:36 9702475104 DMG DURANGO OFFICE PAGE 04107 ,A,s you can see from the water budget, under "tto~rztt.ai" weather comditior-s about sfx irrigation everts arc roquired throughout the gitowing season to meet the water needs of alfalfa: one in May, two in tone, two in July, and one in August {if enough irrigation water is available, then two irrigations could be scheduled in August, rnr one ire August and one in early September). Below is a table which lists the average coxtsunaptive water use of alfalfa growing in the Nucla area, and the time it takes for the drop to consume 3.$ inches of water, or in other wrnrds, the tune between irrigation events: Ma June 7u1 August S ember Average Consumptive water use of Alfali:a 0.12 0.18 0.22 0.19 0.12 In./Da Time $etween In~igation Events 32 21 17 20 32 ------. {Days) Yn my sideroll sprinkler design I used a peak consumptive water use of 0.25 inches/dap, slightly higher than the arter'8-ge consumptive use of 0.22 inchesld,ay that you see iin July - again, I have designed canserv,atively to meet the potential extreme terteperatuxe conditions. VVltat needs to be stated here is that in both t1a.e months of May and September only 1 cfs is x`eally needed to irrigate the alfalfa crap sufficieirtly since the turnaround tixtte is 32 days, Two siderolls, each usiirtg O.S cfs can run simultaneously for 13 days to irrigate 4d acres, then they can be shut down attd. the third sideroll, using only 0.5 cfs, can be run to irrigate tb~e remaining 23 acre field. I've also includedl a spreadsheet that lists the average monthly delivery of CC-Ditch water to the Nacla Pack for the last ten years. I've factored i.Mt ditch delivery loss of 12%, from information provided by 7]catk Naslundl, CC-Ditch Company Superintendent. )< have a column far the quarnity of irrigation water that 50 shares (the amount leased to New Horizon Mine by the Morgans) would equate to each nxmth given the atnourtt of water delivered. And per the above discussion of irrigation scheduling for alfalfa growing in Nucla under tiro three sideroll sprinkler systEm, I have included a "Target" column for the amount of irrigation water needed each montla~. l~inally, there t`s a column listing the difference between tree SO shares of water delivered and the amount needed to irrigate alfalfa sufficiently- As you can see from the difference colurrm, in the last ten years thence have only been three months out of fifth that the CC-Ditch Company was not able to deliver, by arty significant number, the "target" quantity of irrigation water needed for our srystem. The three months are June-199'1, July-2002, and ,A,ugust-2002. As most of you knew 2002 was a severe dtnught year, with some of the driest naotYtits bn record. You naay wander why I did not list July-1998 and July-1999 as months tb~at were "significantly" under-supplied )!n both of those years the diffee~ettce iri water deliv~rEd ar~d water receded in J~u1y was only -0.1 l cfs/day. If you spread this deficiency among three siderolls, each sideroll will stx'ii leave availablle 93% of its design capacity, aced the sprinklers will still work ~- just a little less water will be appliedf In August of 1999, another deficit month, the CC-Ditch was short dawn for some time du~w to heavy rainfall events (personal communication, with Dean. Naslund, CC- bitch 5uperindecda~at}, in which case f.~ners probably did not need, to irrigate their mops.