2011-05-12_PERMIT FILE - M2011028 (2)

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CHAPTER 5 PURPOSE AND NEED, RECOMMENDATIONS AND COMMITMENTS Reclamation will ensure that development of non-binding end uses and conveyance systems avoid or minimize construction impacts to wetland and riparian vegetation wildlife habitat located within the potential corridor alignments of the non-binding water conveyance pipelines and that construction zones are the minimum necessary to meet project objectives as described under Mitigation for Refined Alternative 4 Wildlife Impact 7 in Section 3.5. If avoidance is not possible, Reclamation will require that a riparian/wetland habitat mitigation and a monitoring plan is developed to compensate for the loss of habitat value. 5.4.6 Aquatic Resources Commitments The Service recommended that water pumped to Ridges Basin Reservoir from the Animas River be delivered into the reservoir at an elevation below the thermocline. This could lessen the likelihood of periodically having reservoir water temperatures becoming too warm to support trout and could increase oxygen levels in the reservoir. Reclamation does not believe there is sufficient information to adopt this measure at this time. Reclamation will, therefore, fund a more further detailed evaluation of Ridges Basin Reservoir's expected limnological conditions to better determine whether or not there is a significant concern to include this recommendation in the project plan. This commitment is described under Mitigation for Refined Alternative 4 Aquatic Resources Impact 2 in Section 3.6. The evaluation will be completed in coordination with the Service as part of the design data collection activities. Reclamation will develop and implement a monitoring program at Ridges Basin Reservoir to determine the extent of bioaccumlation of trace elements in fish within the reservoir. The reservoir basin's vegetation will be largely cleared in order to reduce the magnitude of productivity and reduction potential. This, in turn, will limit mercury becoming methylated, the form in which it is available to bioaccumulate within the food chain. Trout will be the only fish stocked. Trout are not at the top of the fish food chain; therefore, they will not be expected to accumulate significant levels of bioaccumulated trace elements. The program will last two consecutive years and be initiated two years after the reservoir is filled. If significant bioac cumulation effects are identified, Reclamation will work with the appropriate local, state or federal agencies to either minimize the impact or otherwise offer protection to potentially impacted fish and wildlife species and to possibly post human fish consumption advisories at the reservoir. This commitment is also described under mitigation for Refined Alternative 4 Aquatic Resources Impact 3 in Section 3.6 To minimize downstream stranding of fish due to the operation of the pumping plant, changes in the pumping will be staged in the following manner: An increase in pumping not to exceed 50 cfs per hour (hr) stage decrease and a decrease in pumping not to exceed 100 cfs/hr (stage increase) when natural river flows are above 500 cfs. At lower flow, these ramping rates could substantially change river stage. Therefore, when river flows are at or below 500 cfs, increases in pumping will not exceed 25 cfs/hr and decreases in pumping will not exceed 50 cfs/hr. This commitment is also described under Mitigation for Refined Alternative 4 Aquatic Resources Impact 6 in Section 3.6. Seasonal bypass flows will be met (ranging from 125 - 225 cfs) as described under mitigation for Refined Alternative 4 Aquatic Resources Impact 1. Monitoring studies of project-affected waters on the Animas River will be implemented both prior to and continuing for at least four years after project operations begin (project pumping). These studies will be designed to better define the native fishery, to include better understanding apparent problems with native sucker recruitment, and to monitor trout populations. If it is concluded that the operation of the project is having significant adverse impacts to the downstream aquatic ecosystem, Reclamation will make every reasonable effort to modify project operations to either reduce or eliminate these impacts. 'vileempinuche Construction n 5.4 ENVIRONMENTAL COMMITMENTS .d,?t?r?7%A .QmO°0. Box AA - TowaJc, CO Q w9tr;?ptT H - P.46e H -?T