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c) L~ ,~ ~ ~~r ~~ G Colonel John N Reese ORA F T 16 Bioloqical Environment Food supply, predation, and competition are important elements of the biological environment. Food supply is a function of nutrient supply and productivity, which could be limited by the presence of contaminants. Predation and competition from nonnative fishes has been identified as a factor in the decline of the endangered fishes. Depending upon species- specific tolerance levels, nonnative fishes may have competitive advantages in habitats damaged by the presence of contaminants and altered flow regimes. EFFECTS OF THE PROPOSED ACTION Water Ouantitv To determine the effects of the Project on water quantity and alteration of the hydrologic regime, an analysis of flow changes was conducted. This analysis compared the effects of the Project to the pre-Project section 7 baseline. The analysis included hydrologic information from the u.S. Geological Survey gaging station at Shiprock, New Mexico. Three levels of development were simulated: (1) historic gage, (2) section 7 environmental baseline, and (3) baseline plus the Project (post-Project). Two wet, two dry, and two average years were selected for analysis based upon total annual water volumes. Because the period of record used for the Animas-La Plata Project hydrologic analysis was 1935 to 1962, and because computer diversion records for Red Mesa Reservoir were only available for years beginning in 1975, the Red Mesa Reservoir analysis could not be matched year-by-year with the Animas- La Plata analysis. Instead, wet, dry, and average years for which computer records were available for Red Mesa Reservoir were matched with earlier similar years for which the Animas-La Plata hydrologic analysis was performed. The years matched were: wet: 1936 and 1992, 1948 and 1986; dry: 1945 and 1990, 1951 and 1977; and average: 1935 and 1989, 1944 and 1978.. Table 2 shows the historic, baseline, and post-Project flows for the specified years. Again, the baseline flows identified in Table 2 do not reflect changes in Navajo Dam operations as required in the reasonable and prudent alternative for the Animas-La Plata Project.