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<br /> <br />. <br />-- <br /> <br /> <br />1392 <br /> <br />would have occurred without the <br />smaller, however, than would occur <br />in the 1961-64 studies. <br /> <br />Project. The increase of inflow is <br />if the Project were operated as assumed <br /> <br />The studies show that depletions to the inflow to John Martin Reservoir <br />will occur at certain levels of excess irrigation. The effects of excess <br />irrigation are discussed in Chapter F. <br /> <br />The studies also show that depletions of the inflow to John Martin <br />Reservoir will occur when the 39,000 acre-feet joint-use pool is used. If <br />the joint-use pool is only used to store water when John Martin Reservoir <br />is spilling or anticipated to spill, as is the intent of the Operating <br />Principles, then the depletion caused by this additional storage will all <br />occur when the water would not be usable to the beneficiaries of John <br />Martin Reservoir. In fact, the additional storage in Trinidad Reservoir <br />when John Mart in is spi 11 i ng will resu It in enhancements to the inflow to <br />John Martin Reservoir because of the subsequent increase in irrigation and <br />the resultant return flows from the Trinidad Project. <br /> <br />Table 8 and Table 9 show the impacts on the usable inflows to John Martin <br />Reservoi r for the vari ous studi es run over the 1925-57 peri od. The resu lts <br />shown in Tables 8 and 9 were computed by eliminating the impacts that <br />occurred during the months that John Martin Reservoir would spill. ' <br /> <br />While the use of the full 39,000 acre-foot pool does not deplete the usable <br />inflow to John Martin when the joint-use pool is used only to store water <br />when John Martin is spilling, the usable inflow may be depleted if the <br />joint-use pool is used to store water at other times such as the winter <br />inflows or the transfer from the Model Right. <br /> <br />One series of stUdies evaluated the effects of various levels of bypasses to <br />Ninemile and Highland. These studies were run because no bypasses for <br />Ninemi le and Highland were made during the 1979-84 review period. Article <br />IV O. 1. (a) of the Operating Principles clearly gives the Colorado State <br />Engineer the responsiblity to determine the bypass to meet senior rights "...to <br />actually benefit such rights without unnecessary waste through channel lOsses." <br />Co 1 orado has provi ded the Bureau an exp 1 anat i on of the "fut i 1 e call" admi n- <br />istration on the Purgatoire River by letter of November 15, 1988 from <br />Mr. Denn i s Montgomery of Hi 11 & Robbi ns P. C. In genera 1 they have deter- <br />mined that bypasses will not reach Ninemile or Highland if the flows at <br />the Thatcher Gauge are less than 100 c.f.s.; therefore, bypasses are not <br />made unless the flow at the Thatcher Gauge exceeds the 100 c.f.s. <br /> <br />Table 10 and Table 11 show the shortage in the water supply available to meet <br />the needs of project lands determined by the various studies run on the <br />1925-57 period. As can be seen comparing the information in Tables 10 and 11 <br />with Tables 5 and 6, many of the practices and conditions studied will <br />result in greater increases (reduced shortage) to the Project supply than <br />decreases to the inflow to John Martin Reservoir. This situation may pro- <br />vide opportunities for the Purgatoire River Water Conservancy District to <br />enhance their water supply by purchasing water in the Arkansas River to <br />mitigate reductions of the inflow to John Martin Reservoir. <br /> <br />It is our conclusion that the Purgatoire River Water Conservancy District, <br />the States of Co 1 orado and Kansas and the Bureau of Rec 1 amat ion shou 1 d work <br /> <br />29 <br />