Correspondences Concerning Upper Colorado Biological Opinions 1993

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Elizabeth Estill, Regional Forester FOREST TOTAL AF 11 HISTORIC NEW Arapaho Roosevelt 11.52 11.52 0 Grand Mesa, Uncompahgre, and Gunnison 726.49 613.369 113.119 Medicine Bow 38.28 38.28 0 Rio Grande 115 115 0 Routt 62.68 36.294 26.387 San Juan 157.42 136.42 21 White River 218.96 134.27 84.69 IF- TOTAL 1,330.35 The Service understands that the depletion figures presented in the biological assessment are estimates of the projected forest activities over a 15 -month period. These activities could change within the timeframe covered in this opinion; some may not occur and others may be added. Therefore, the Forest Service will require each of the seven national forests to track water depletions for each forest activity. Each forest is required to submit a report to the Regional Forester by August 30, 1994. The Regional Forester will then provide a summary report to the Service by September 30, 1994. This summary report should include the following information for each project: (1) project name, (2) project location (district, township, range, and section), (3) total water diverted (if applicable) in acre -feet, (4) average annual depletion in acre -feet, (5) timing of depletion, (6) identify if new or historic depletion, and (7) total of all depletions less than 125 acre -feet annually. It is important to include information on whether each depletion is new or historic occurring prior to January 1988, because the Service addresses new and historic depletions differently under the new Section 7 agreement of March 11, 1993. This programmatic process will need to be ongoing to address f6ture water depletions from the seven national forests. BASIS FOR BIOLOGICAL OPINION This biological opinion addresses an average annual depletion of approximately 1,330.35 acre -feet from the Upper Basin. Water depletions in the Upper Basin have been recognized as a major source of impact to endangered fish species. Continued water withdrawal has restricted the ability of the Colorado River system to produce flow conditions required by various life stages of the fishes. Impoundments and diversions have reduced peak discharges by 50 percent since 1942, while increasing base flows by 21 percent in some reaches. These depletions, along with a number of other factors, have resulted in such drastic reductions in the populations of the Colorado squawfish, humpback chub, bonytail chub, and razorback sucker that the Service has listed these species as endangered and has implemented programs to prevent them from becoming extinct.