Analysis of Colorado-Big Thompson Project Operation With Respect to East Slope Diversions and Non-Charge Deliveries

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`w • Maryanne C. Bach Brian Person October 6, 2000 Page 7 through utilization of available snowpack and runoff forecast data, more sophisticated operating scenarios are possible and will achieve similar results. Helton & Williamsen conclude that Adams Tunnel diversions from the Western Slope could be reduced by an average of over 13,600 acre feet per year through utilization of the East Slope storage decrees. More importantly, an average of 18,000 acre feet of peak flow enhancement flow is possible in the PBO target years (12,900 cfs to 26,600 cfs). If the non- charge program was eliminated, the Adams Tunnel diversions could be reduced by an average of up to 50,000 acre feet per year, with a corresponding increase in peak flows in the target years of over 70,000 acre feet. This beneficial result can be achieved without any adverse affect on CBT Project contract water supplies. Because this method of operation is required by the CBT Project's authorizing legislation, Senate Document 80, and Reclamation's obligations to assist in the recovery of the endangered fish species, it is incumbent on Reclamation to implement it as soon as possible. ENDANGERED SPECIES ACT OBLIGATIONS All of these unauthorized diversions have a real impact on the Colorado River fish listed as endangered under the Endangered Species Act ( "ESA "). The River District's engineering consultant has estimated the impact of the non - charge program and the failure to utilize the East Slope water rights as was contemplated in Senate Document 80, and the amounts are substantial. There is real and significant detrimental impact to flows in the 15 Mile Reach, and downstream critical habitat below the 15 Mile Reach, during the spring runoff period. Operation of CBT in this manner not only breaches Senate Document 80 as discussed above, but is also inconsistent with Reclamation's responsibility to conduct its operations in a manner that furthers the purposes of the ESA. Sections 7 and 9 of the ESA prohibit Reclamation from allowing excessive or wasteful exports of water from the Upper Colorado River Basin which would harm or jeopardize the listed fish or adversely modify or destroy designated critical habitat. Reclamation is clearly the owner of the CBT Project facilities pursuant to Articles 8 and 37 of the repayment contract for the Project. As acknowledged by Reclamation in the Rio Grande Silvery Minnow litigation, Reclamation's ESA obligations as holder of title to project facilities is much broader than if the facilities were owned by others, even extending to the imposition of bypass requirements for