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<br />.. ..........'.;".. <br /> <br />002~77 <br /> <br />Description of Alternatives <br /> <br />Thirteen alternatives (II structural and 2 non-structural) were identified and evaluated to provide <br />6,000 AF of delivered streamflow augmentation. A "No Action"alternative also was evaluated. <br />Structural alternatives were subdivided into single-source and multiple-source options (Table 20). <br />The following narrative describes each of the alternatives and the hydrologic assumptions used to <br />model them. <br /> <br />Non-structural alternatives <br /> <br />Alternative 1 (No Action): This alternative provides no flow augmentation for endangered fishes. <br /> <br />Alternative 2: Supply interruption contracts with irrigators were evaluated as a sole-source option, <br />.as well as in combination with other augmentation sources (Alternative 13). Any such leases would <br />be pursuant to voluntary, consensual agreement(s) with one or more water users and would be fully <br />compensated by the Recovery Program at fair market value. Long-term contracts would provide <br />the greatest certainty for the fishes. However, shorter terms may be considered in the interim until <br />long-term contracts become available. To model this alternative, instream flows were assigned a <br />higher priority (i.e., earlier adjudication date) than one or more senior water users, allowing the <br />model to call out those users when augmentation was necessary. <br /> <br />Conservation measures, which could be used in conjunction with supply interruption contracts, were <br />modeled by adjusting irrigation efficiencies. "Conservation," in this case, is intended to reduce <br />diversions from the river. Traditional flood-irrigation practices used in the Yampa River Basin are <br />only 60% efficient, requiring lOAF be diverted from the river for every 6 AF of consumption. <br />Sprinkler or drip irrigation requires less water to be diverted. For modeling purposes, efficiencies <br />were raised from 60% to 80%, requiring smaller volumes of diversion to achieve the same level of <br />consumption. However, higher efficiencies also would result in smaller volumes of return flows. <br /> <br />Alternative 3: As a result of concerps expressed by the Service and other Recovery Program <br />participants, the CWCB withdrew the base-flow and recovery-flow instream flow filings on the <br />Colorado and Yampa rivers. In compliance with the Colorado River PBO (USFWS 1999), water <br />users from both the Upper Colorado River Basin and Front Range have delivered water from their <br />reservoirs to augment instream flows. These water deliveries are administered to support flow <br />recommendations in the Colorado River; therefore, new instream flow water rights may not be <br />. needed for this purpose. <br /> <br />The Recovery Program agreed to evaluate the need for further instream flow water rights every <br />5 years. Upon completion of this review, a determination will be made regarding the need to protect <br />instream flows for the endangered fishes. During the final year of the first 4-year period, the <br />Recovery Program and CWCB will develop a process to assess the need for further instream flow <br />protection for endangered fishes. Therefore, beginning 5 years after a Yampa PBO is completed, <br />the Recovery Program and CWCB will evaluate the performance of this management plan in terms <br />of meeting current or revised flow recommendations. Although instream flow water rights could <br />stand alone as a means to satisfy base-flow recommendations, their junior priority would make them <br />subject to senior calls during drier conditions, when they would be most needed. However, they <br />could provide greater reliability in combination with firm water supplies (Alternatives 4-14). <br /> <br />Management Plan for Endangered Fishes in the Yampa River Basin <br /> <br />44 <br />