Laserfiche WebLink
More detailed tables, showing monthly flows for the entire period of record considered in this <br />report, are found in Attachment E. Attachment E also contains tables estimating the number of <br />months a "call" would occur on the river under the different alternatives including No Action. <br />As can be seen from Tables 1 through 4, water supplies in Blue Mesa would be managed under <br />Alternatives A and B so that no significant impacts to water uses would occur. Water available <br />to downstream diverters would not be significantly affected and thus "calls" on the river should <br />not increase appreciably. This would protect junior water users upstream and downstream from <br />Blue Mesa Reservoir. When flows are 1,095 cfs or greater at the Whitewater Gage as shown <br />in Attachment E, there is sufficient water for Redlands Diversion (750 cfs), other seniors (45 <br />cfs), and endangered fish (300 cfs). Under Alternative C, more effect on water uses is noted <br />and the possibility of junior water rights being "called out" increases. Table 5 on page 20 <br />summarizes the number of months in which shortages or river administration (calls) would occur <br />under the alternatives. <br />Water supplies in Blue Mesa would be used for the interim agreement but large drawdowns are <br />not seen in the hydrology tables except in a series of dry years such as 1989 through 1990. In <br />a dry period such as this, delivery of 300 cfs to the endangered fish and other Aspinall Unit <br />releases could reduce the reservoir content by over 100,000 acre -feet (see tables in <br />Attachment E). This represents a "worst- case" situation, because improved streamflow <br />forecasting and operating criteria could reduce the impacts of a dry period. Also, the 1990 data <br />reflects attempts to maintain 300 cfs in nearly all months. In a dry year, shortages would be <br />shared by users throughout the basin, including the endangered fish; this will be specified in the <br />water agreement under all alternatives. In extreme drought years such as 1977, minimum flows <br />of 300 cfs would not be maintained and fish habitat would be reduced. <br />As indicated previously, there are several water projects being considered for development in <br />the Gunnison River. The water rights for these projects would not be affected. Concerns were <br />expressed in public meetings that the fish passage or interim water agreement could lead to <br />establishment of a more stable population of endangered fish species in the Gunnison River, and <br />this would make construction of the Dominguez Project more difficult to permit. The goal of <br />the proposed actions is to establish a larger self - sustaining population of the endangered fish in <br />the Gunnison River. The proposed location of the Dominguez Dam is in a reach of the river <br />already designated as critical habitat for the endangered fish and already occupied by the fish, <br />thus protection for the fish exists on the river and will exist whether or not the fish passageway <br />and interim agreement are completed. Recovery of the fish and their removal from the <br />- -- -- endangered species list is probably the most advantageous thing that could occur with respect <br />to future water developments. <br />Previously, 148,000 acre -feet of storage in Blue Mesa Reservoir was planned for use by <br />endangered fish, and the interim agreement water will come from this storage. Thus water will <br />not be removed from other possible uses. In addition, the water delivery agreement will be an <br />interim or temporary agreement; and effects on water uses as well as fisheries will be monitored <br />to provide data for eventual development of a long -term contract. <br />17 <br />