Laserfiche WebLink
Agricultural demands are a function of the assumed system efficiencies and are limited by the <br />? <br />physical capacity of the ditches. The values for these parameters were also obtained from prior <br />investigations for GUNMOD. <br /> <br />The timing and location of irrigation return flows from the project canals are based on the same <br />? <br />assumptions used in GUNMOD. <br /> <br />In order to simulate the hydrologic conditions that would trigger a call against junior water <br />? <br />rights on the Uncompahgre, MODSIM will look at the total flow through the link at the Colona <br />stream gage for the month of June, and will initiate the call if this June streamflow is less than <br />or equal to 29,000 acre-feet. This value was based on a regression analysis comparing the June <br />flows to the July 15 flow at Colona to establish conditions in which the July 15 flow is 250 cfs <br />or less (see previous discussion). The call is assumed to be only up to 245 cfs delivered to the <br />head gate of the M & D Canal, and will be in effect for 4 weeks. <br /> <br />The Uncompahgre call described in the previous paragraph will only trigger if the Gunnison <br />? <br />Tunnel is flowing full, either with direct flow or storage releases <br /> <br />MODSIM will attempt to keep the Gunnison Tunnel flowing full during the irrigation season. <br />? <br />If the inflow to Blue Mesa Reservoir is greater than 1,135 cfs, the tunnel's direct flow right will <br />be used to satisfy the agricultural demand from the project canals. To the extent that the inflow <br />to Blue Mesa is less than 1,135 cfs, the UVWUA will call for storage releases from its <br />exchange account in Blue Mesa Reservoir (see Task Memorandum 1.15-21). <br /> <br />If the tunnel is flowing full (either with direct flow or storage water), the agricultural demand is <br />? <br />not fully satisfied, and the Uncompahgre call is not triggered, MODSIM will call for a storage <br />release from its accounts in Ridgway Reservoir (first from the exchange account and then from <br />its own allocation of Dallas Creek Project water [see Task Memorandum 1.15-20]). <br />3.0 CONCLUSIONS AND RECOMMENDATIONS <br />The operations of the Uncompahgre Project and its principal operating entity the UVWUA, play a major <br />role in the administration of water rights and the delivery of water in the Gunnison-Uncompahgre river <br />basins. During Phase IIa, interviews were held with the Division Engineer, water commissioners, and <br />the UVWUA to gain a better understanding of the operational policies related to diversions from the <br />Gunnison River via the Gunnison Tunnel and the distribution of water to the large Project Canals. The <br />MODSIM prototype has been designed to reasonably represent the complex operations associated with <br />the ?good neighbor? policies of the UVWUA in which its senior rights are subordinated to junior rights <br />in both the Gunnison and Uncompahgre basins. The model is reasonably flexible to allow the user to <br />modify the assumptions related to the good neighbor policies and the priority of use form the reservoir <br />storage accounts available to the UVWUA. It is recommended that the CRDSS consultant fully test the <br />MODSIM model and assumptions to ensure full functionality of the model with respect to the <br />UVWUA?s informal procedures for diversions and storage operations. <br />The on-line documentation for the MODSIM prototype contains additional information related to the <br />assumptions and development of the various direct flow and storage elements of the Uncompahgre <br />Project operations in the water rights planning model. <br />7 <br />A275 01.09.95 1.15-25 Fosha, Hyre <br />