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<br />~ .', ':""'~, <br /> <br />CWCB Members <br />January 21, 1998 <br />Page 2 <br /> <br />~" '~~.'~t <br />.-,C,) <br />..;i- <br />l' <br /> <br />. <br />. <br /> <br />instream flow use, Aspen wants to ensure that all diversions junior to the Board's ISF right on <br />Castle creek are being curtailed. <br /> <br />e <br /> <br />To accomplish this, Aspen will install measuring devices at the Midland Flume and will <br />continuously measure stream flows in Castle Creek during low streamflows. . In addition, Aspen <br />proposes to develop a comprehensive stream model to aid in the administration of Castle Creek. <br />Aspen will provide the measuring and monitoring services to determine when a call should be <br />placed against junior water rights to protect the Board's decreed instream flow on Castle Creek. <br />Also at its cost, Aspen will, to the extent necessary, rebuild or reconfigure its Midland Flume to <br />permit the continuous bypass of at least 12 cfs of water in Castle Creek. <br /> <br />Aspen requests that its obligation under this agreement not exceed 12 cfs, the amount of the <br />Board's decreed instream flow right. Also, Aspen wants to retain the right to divert its water <br />rights if needed for municipal purposes under extraordinary drought or emergency conditions in <br />its municipal water supply. In addition, Aspen requests that the Board exempt Castle Creek and <br />Conundrum Creek (a tributary of Castle Creek) from its De Minimis Rule as provided for in <br />Section 9.33 of the ISF Rules and Regulations. <br /> <br />Finally, Aspen requests that the Board authorize Aspen to be its agent for administration and <br />monitoring of the Board's instream flow right on Castle Creek. Aspen will not place a call under <br />its own priorities to supply water for instream flow uses. The calls are restricted to the Board's _ <br />instream flow priority. By January I of each year, Aspen will provide an annual report to the .. <br />Board on the previous year's activities, including the operation of this Agreement and the actions <br />taken by it as the Board's agent. The report will also specify Aspen's operations planned for the <br />upcoming year. At its own option, the Board may revoke this authorization for Aspen to act as <br />its agent by undertaking all administration and monitoring responsibilities. <br /> <br />Castle Creek Water Availability Analvsis <br /> <br />Aspen's water rights are senior to the Board's instream flow water rights; therefore, Aspen can <br />legally deplete stream:flows to an amount less than the Board's decreed ISF right on Castle Creek. <br />However, Aspen has adopted a policy to forego the flow necessary to maintain the ISF right <br />downstream of its intake structures. <br /> <br />Currently, there is no gage on Castle Creek; therefore, the necessary data is not availableto estimate <br />strearnflows and how often the Board's right would benefit from Aspen's proposed operation. <br />However, based on a report by Enartech Inc. (1994) entitled, "Evaluation of Raw Water <br />Availability", shortages in Aspen's water supplies may be expected in the winter months of three <br />out of 23 years studied (1970-1992). This report assumes that Aspen will continue to provide <br />sufficient water to maintain instream flow downstream of all Aspen intake structures. The same <br />report estimates that shortages of Aspen's irrigation water on Castle Creek could occur in the late <br />summer months in 9 out of 23 years studied. The Enartech report concludes that strearnflows are <br />generally higher than the ISF right following diversions by the City and other local water users. <br />However, during dry periods, stream:flows may not be high enough to meet existing municipal _ <br />demands and at the same time, maintain the Board's ISF right. In addition, as future development .. <br />