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CHAPTER 5 <br />PURPOSE AND NEED, RECOMMENDATIONS AND COMMITMENTS <br />The conservation measures include Reclamation's commitment to operate Navajo Reservoir and the <br />Durango Pumping Plant to mimic the natural hydrograph of the San Juan River to benefit the endangered <br />fish and their habitat. Also, Ridges Basin outlet facilities will be designed to prevent escapement of <br />nonnative fish, that might compete with native fish, into the Animas or other area waterways. <br />Reclamation will develop and implement a monitoring program for potential adverse bioaccumulation of <br />trace elements in bald eagle food items in Ridges Basin Reservoir. If the program identifies a problem <br />with trace elements, Reclamation will develop and implement an action plan to minimize impacts to bald <br />eagles. Bypass flows compatible with the endangered fish recovery efforts will be incorporated into the <br />project plan to promote natural recruitment of cottonwood trees. This should avoid impacts to future <br />bald eagle habitat. Also, electrical transmission lines associated with the project will be designed to <br />avoid injury to raptors, including bald eagles. <br />I Project wildlife and wetland mitigation areas should provide high quality, protected habitats for species <br />such as the southwestern willow flycatcher and bald eagle in the area. <br />5.4.8 Geology and Soils Commitments <br />I Reclamation will reduce or eliminate the potential for earthquake damage to the Ridges Basin Dam site <br />through specific design specifications. Dam specifications will require design performance to withstand <br />a maximum credible earthquake for seismic sources in the vicinity of Ridges Basin Dam site as described <br />under Mitigation for Refined Alternative 4 Geology Impact 1 in Section 3.8. <br />Reclamation will develop and implement a controlled program for filling Ridges Basin Reservoir to <br />reduce the potential for induced seismic impacts as described under Mitigation for Refined Alternative 4 <br />Geology Impact 2 in Section 3.8. <br />Reclamation will develop and implement a facilities operation program that includes monitoring the <br />reservoir shoreline and slopes for landslide and slumping. Reclamation will also provide for public <br />notification and control public access in areas where high landslide and slumping potential exists as <br />described under Mitigation for Refined Alternative 4 Geology Impact 3 in Section 3.8. <br />Reclamation will develop an engineered process plan to limit, control, and manage dam site methane gas <br />releases during construction. Reclamation will also monitor the area for methane gas releases during <br />operations as described under Mitigation for Refined Alternative 4 Geology Impact 4 in Section 3.8. <br />Reclamation will investigate the potential of gas release due to man-made intrusions within Ridges Basin <br />and the proposed dam site. Specifically, construction investigations will study the integrity of abandoned <br />exploration wells and the Gates Coal Mine as described under Mitigation for Refined Alternative 4 <br />Geology Impact 5 in Section 3.8. <br />Reclamation will mandate that construction contractors use and implement measures contained in erosion <br />control guidelines and BMPs to control soil erosion from construction areas as described under <br />Mitigation for Refined Alternative 4 Soils Impact 1 in Section 3.8. <br />Reclamation will develop and implement a program to control reservoir filling and drawdown at rates <br />sufficient to reduce significant erosion and sedimentation potential as described under Mitigation for <br />Refined Alternative 4 Soils Impact 2 in Section 3.8. <br />oc, CO 8E <br />5.4 ENVIRONMENTAL COMMITMENTS 5-16 P.O. Bon AA - Tow <br />e GIN 1MAS 6 c.P= t L'2 6QAV t <br />?}c{d(.!:,(T A PCws- E (-i