2010-11-22_REVISION - M2009023 (7)

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decrease in spring peak flows of 45 percent, while approximately doubling winter base flows at the Bluff gauge in Utah. Similar comparisons can be made at the upstream gauges at Shiprock and Farmington, New Mexico. Significant depletions and redistribution of flows of the San Juan River also have occurred as a result of other major water development projects, including Navajo Indian Irrigation Project and the San Juan-Chama Project. At the current level of development, average annual flows at Bluff, Utah, already have been depleted by 30 percent. By comparison, the Green and Colorado rivers have been depleted approximately 20 percent (at Green River) and 32 percent (at Cisco), respectively. These depletions, along with a number of other ' factors, have resulted in such drastic reductions in the populations of Colorado pikeminnow and razorback sucker throughout their ranges that the Service has listed these species as endangered and has implemented programs to prevent them from becoming extinct. As explained above, 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. Consequently, all,projects previously built or consulted on, and those State or private projects presently being builf or considered that deplete water from the San Juan River Basin are in this project's baseline (Table 1). The baseline does not include the effects of the action under review, regardless of whether it has previously undergone formal section 7 consultation. Operating Navajo Reservoir to mimic the natural hydrograph of the San Juan River, by following the San Juan River flow recommendations (Holden 1999), is being implemented to the extent currently possible by the Bureau of Reclamation and, therefore, is considered part of the baseline conditions for this project. Water Quality Surface and ground water quality in the Animas, La Plata, Mancos, and San Juan River drainages have become significant concerns (Abell 1994). Changes in water quality and contamination of associated biota are known to occur in Bureau of Reclamation projects in the San Juan drainage (i.e., irrigated lands on the Pine and Mancos rivers) where return flows from irrigation make up a portion of the river flow or other aquatic sites downstream (Sylvester et al. 1988). Increased loading of the San Juan River and its tributaries with heavy metals, elemental contaminants such as selenium, salts, polycyclic aromatic hydrocarbons (PAHs), and pesticides has degraded water quality of the San Juan River in critical habitat. Information on existing water quality in the San Juan River has been derived from data gathered by the Department of the Interior (DOI) as part of its National Irrigation Water Quality Program investigation of the San Juan River area in Colorado, New Mexico, and Utah; results from Reclamation's water quality data for the Animas-La Plata Project; and ongoing contaminant monitoring and research conducted as part of the SJRIP. Some of this information has been presented in Blanchard et al. (1993), Abell (1994), Wilson, et al. (1995), Thomas et al. (1998), and other references cited in Simpson and Lusk (1999). Thomas et al. (1998) found that concentrations of most potentially toxic elements analyzed from the San Juan River drainage in their study, other than selenium, were generally not high enough to be of concern to fish, wildlife, or humans. 18