Laserfiche WebLink
<br />I <br />. <br />I <br />. <br />. <br />'. <br />. <br />. <br />I <br />. <br />I I <br />. <br />I <br />I <br />. <br />I <br />I <br />I <br />I <br /> <br />modeled individually. <br />consumptive use demands, <br /> <br />These water rights <br />and return flows. <br /> <br />are <br /> <br />modeled <br /> <br />as <br /> <br />diversions, <br /> <br />Most small (in terms of quantity) irrigation water rights and a few small <br />municipal and domestic rights are represented as aggregated depletions rather <br />than as diversion and return flows (depletions are the difference between <br />di vers ions and return fl ows) . Thi s was done because the 1 arge number of <br />diversions in the Study Area dictated a simplified approach at this <br />pre 1 imi nary 1 evel of study. These ri ghts were aggregated by geographi ca 1 <br />1 ocat i on and by rel at i ve water rights pri ority. Four pri ority cl asses were <br />defined using the priorities of the major water rights to divide the smaller <br />rights into the four classes. An agreement between the USBR and the CRWCD and <br />the file documents supporting the agreement obligates the USBR to allow <br />junior, in-basin, upstream appropriators the use of water in an amount not to <br />exceed 60,000 af (U.S. Department of the Interior, 1984). This agreement is <br />commonly referred to as the "Curecanti Subordination." The geographical <br />distribution of the 60,000 af of depletions is as follows: 20,000 af in the <br />drai nage between Crystal and Bl ue Mesa Reservoi rs and 40,000 af above Bl ue <br />Mesa Reservoir within the Gunnison River Basin. The current junior upstream <br />depletions are far less than these amounts. Issues surrounding the <br />implementation of the agreement and its administration have not yet been fully <br />resolved. However, the issues do not affect the study's hydrologic modeling <br />of the agreement including the modeling of historic Aspinall Unit operations. <br /> <br />The direct-flow water rights for the Aspinall Unit were not modeled <br />individually. In the past, there has been no need for full administration of <br />these direct-flow decrees against upstream junior in-basin appropriators <br />because of the "Curecanti Subordination." Therefore, only the Aspinall Unit <br />storage decrees were modeled so that the hydrologic modeling could be <br />calibrated with historic operations. If a situation arises in the future <br />where in-basin depletions junior to the Aspinall Unit water rights are greater <br />than 60,000 af or out-of-basin diversions are implemented, the USBR may <br />require administration of both the direct-flow and storage decrees. This <br />study has not addressed specific impacts of such administration. The <br /> <br />3-3 <br />