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o (-;.., (.j It then turns north and eventually reenters the extreme southwest corner of Colorado near Four Corners, Downstream of Four Corners, the San Juan River enters Utah and continues northwesterly through the towns of Aneth, Montezuma Creek; Bluff, and Mexican Hat. Utah, and empties into Lake Powell near Piute Farms Wash. i_,"\ ~ ~ Colorado squawfish spawn July 1 to September 1 in cobble/gravel areas typically found in riffle/run habitats. Following hatch, larval Colorado squawfish drift downstream to low velocity habitats. Important habitats during summer low flow (August) are the San Juan's backwaters and secondary channels, used by larvae and young Colorado squawfish. During 1995 investigations under the San Juan Recovery Implementation Program, low \/elocity habitats were more common in August than June and comprised a greater percentage of total habitat upstream from RM 110 than downstream. Low velocity habitats peaked in abundance between'RM 120 and RM 180 (Holden and Masslich 19951. The proposed study focuses on low-velocity habitat use by Age-O and Age-l Colorado squawfish, Low-velocity habitats are riverine embayments and shoreline inconsistencies that form when scoured areas peripheral to sand bars become isolated from the main channel as high flows recede (backwaters) or from main channel obstructions that deter flow (side channels), In low-velocity habitats, young Colorado squawfish remain protected from main channel high velocities, hazards, and further drift. Depending upon the mechanism of scouring, location in the channel, sediment transport, and flow regime, low-\/elocity habitats vary in depth, size, shape, and stability, In turn, these varying physical attributes result in . different chemical and biological conditions among these habitats. Because hydrologic and sediment transport regimes are affected by channel geometry, low-velocity habitat quality also Changes among geomorphic reaches. Additionally, some flow regimes are more conducive to the construction and maintenance of low-velocity habitats, rendering them more abundant in certain seasons or years, depending upon flow regimes, The necessary quality and quantity of low-velocity nursery habitat must be available at certain locations and seasons in the San Juan River to accommodate the influx of drifting Age-O Colorado squawfish from spawnjng areas. Operations from Navajo Dam may have alter13d the natural spatial and temporal dynamics of low-velocity habitat. thus affecting the life history of resident Colorado squawfish. ENVIRONMENTAL BASELINE The environmental baseline includes the past and present impacts of all Federal, State, and private actions and other human activities in the action area; the anticipated impacts of all proposed Federal projects in the action area that have already undergone formal section 7 consultation; and the impact of State or private actions contemporaneous with the consultation process. In formulating this biological opinion, the Service considered adverse and beneficial effects likely to result from cumulative effects of future State, and private activities that are reasonably foreseeable to occur within the project area, together with the direct and indirect effects of the proposed experimental stocking and impacts from- actions that are 12