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. ., >" (' ,t' \ ,,,'-1... ~"""'" ... . assumption that actual diversions of water during the review period were equal to the ideal diversion requirement. In our judgment, Case 1 is more realistic tnan Case 2, but probably still understates the inflow to John Martin Reservoir since it is based on irrigated acreages that are larger than were actually irrigated. The. irrigated acreage uSt!d were obtained from the Colorado Agricul tura1 Statistics which i nc1 ude an unknown amount of lands uutside tne Project. From a standpoi n.. of inJury to downstream users, Case 1 gi ves the most reasonable results. However, none o,f the tnree studies gives a true pic- ture of injury because they do not compare the actual conditiun to a "without proJect" condition. We investigated making the "without project" compari son and conc1 uded ttlat tnere was not suffici ent information availao1e to make IfI!::anin~fu1 comparisons. Tnt! Kansas offici a1 s have argued the impacts of the Project must be eva- luated on an annual basis rather on an average annual basis. This has merit as it applies to the 1979-<i4' review period. John Martin Reservoir bt!~an a filling cycle on Nuvember 1; 1982, culminating in a spill of John Marti n Rt!servo ir in May 1985. As shown in resu 1 ts for Cases 1, 2 and 3 (see Table 4), the inflow to John Martin was depleted during the period. prtlceding the fill cycle, but was enhanced after the beginning of the fill cycle. The depletions before the beginning of the fill cycle resulted in a loss of usable water to Kansas, wh~reas the enhancements occurring after the beginning of the fill cycle were not usable because they were lost in the spill. The average annual neti impact on the inflow to John ~Iartin Reservoir for the review period up i through December 31, 1982 were -2000 acre-feet, -3300 acre-feet and -bOUlJ acre-feet for Cases 1, 2 and 3, respectively. The average annual i~acts for the entire review period were +600 acre-feet, -6lJ0 acre-feet and -i !NO acre-feet. Tile occurrence of depletions before the beginning of the fill cycle and ennanctlment after were a direct result of the large reduction of irrigated acreage during the early years of the, review period. During the early years when less land was irri ~ated tile exc~ss water supply was stored in Trinidad Reservoir. The return flows duringj tnis period were reduced due to less iand beiny irrigated. In the years after the beginning of the fill cycle, more land was irrigated ana, because of an abundant supply, more water was appl ied resulting In increas!::u return flows and enhanced inflow to John i'jartin Reservoir. There is no reason to expect that these circumstances will be repeated ana, tllerefore, .heula have no bearing on future amendments to the operating prin- ciples. NotwitnStanding the circumstances o'f 1979-84 review period, we see no reason why the i mpac ts on J oM ~lart1 n ReSt! rvo i I' snou ld not conti nue to be evaluated on an average annual basiS. The Triniaad ProJect, by its very nature of rert!gulatioll, will result in reduced inflows to Jonn Martin Reservoir in sume years and enhancea flows in other years. Table 25 of tile 1961 Stuay shows annual enhancement of as muCtl as 8,000 acre-feet and an annual depletion uf as much as10,uUlJ acre-feet. The 1961 Study also shows that entlancements to inflow to John Martin Reservoir generally occurred in dry years and depletions occurred in wet year.. ,As illustrated in Table 7 (from Table 25 of the 1901 Study), the Project wh~n compared to historic operation would increase the inflow to John Martin Re$ervoir in 16 of the 21 driest years ,and wou1a decrease the inf'low in 8 of the '12 wettest years. The largest dep1etlons (Rev. 12/27/88) 26