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<br />3313 <br /> <br />U.S., described IJD's recent pl'3ctices as not regularly enforcing its rules on excessive <br />taihvater. <br /> <br />lID measures and reports river diversions, lateral tUl110uts and fann deliveries on a <br />consistcnt basis (Franzoy 2003, p. 3). lID policy is to measure tailwater runoff at least <br />IWlce a day, but available tailwater data were found to be incomplete and inconsistent. <br />Measured drain and tile water flows were not found in the operating reports submitted by <br />lID, Reclamation concludes the lID is not measuring drain and tile flows on a consistent <br />basis, <br /> <br />In 1984 the SWRCB rep0I1ed that during the period from 1965 to 1980, lID diversions <br />from the Colorado River averaged 2,855,000 acre- feet per acre. (Decision 1600 p. 7) <br />Subsequent to this period, two major increases in Colorado River water diversion <br />amounts for lID occurred. The first increase occurred between the periods 1987-88 and <br />1989-90. The second increase occurred between 1994 and 2002. Jensen and Walter <br />described these changes in their 2003 Supplemental Report (Jensen/\Valter Supplement <br />2003, p. 6), as shown below: <br /> <br /> Average <br /> Flow at Increase from '87-88 Leaching Increase Crom '87-88 <br /> EHL Canal & Tailwater <br />Period (acre-It) (acre-It) (%) ( acre- It) (acre-It) (%) <br />1987-1988 2,764,000 659,000 <br />1989-1990 2,944,000 180,000 6.5% 781,000 122,000 18{~/o <br />1994- 2002 3,020,000 256,000 9.3% 878,000 2 I 9,000 33% <br /> <br />Note: The amounts for Flow at East Highline (EHL) Canal constitute the average <br />amount of flow arriving at the District for the periods shown. These amounts <br />were derived by subtracting estimated AAC losses, deliveries above EHL Canal <br />and retum flows, from the diversion amounts. Leaching and tailwater volnmes <br />were estimated as farm delivery minus estimated crop ET. (Source: Jensen/Walter <br />Supplement, 2003, p. 6), <br /> <br />These data indicate that the increase in flow at East Highlint (EHL) Canal has resulted in <br />an 18% mcrease in tailwater and leachwater from the period between 1987-88 and 1989- <br />90 and a 33% increase from the period between 1987-88 and 1996-2002 (Id,) <br /> <br />IrrigatKm water supplied at EHL (minus delivery to non-agriculture) increased from <br />about SA acre- feet per acre of total agricultural land in 1987 to about 6.0 acre- feel per <br />acre in 1990, and to a recent maximum of about 6.3 acre- feel per acre in 1996 <br /> <br />July 2, 2003 <br /> <br />27 <br /> <br />Detenninations and Recorrunendatioli; <br />For lID - Calendar Year 2003 <br />