2009-09-25_PERMIT FILE - M2009076 (41)

Home Browse Search

the OU 3 ROD is withdrawn. Implementation of the Big Five Project will expedite OU 3 remedial action objectives with respect to water quality goals. SUPPORT AGENCY COMMENTS CDPHE is the lead agency for the SITE. EPA has reviewed the revised remedy and supports the implementation of the remedy as presented in this ESD. STATUTORY DETERMINATIONS The changes to the remedy selected in the 1991 OU 3 ROD, as presented in this ESD, were made in accordance with all applicable regulatory and statutory requirements as required by Section 121 of CERCLA. A comprehensive evaluation of ARARs was conducted as part of the OU 3 remedy selection, which as noted above, included remedies such as those now being selected for the Big Five Tunnel discharge. ARARs were recently reviewed in the September 2004 Five Year Review Report. Treatment of the Big Five discharge will meet all ARARs, Closure of the pond will be performed through a work plan approved by the agencies. That approval will include a condition that the plan meet all applicable and relevant and appropriate state and federal standards. • Considering the new information that has developed and the changes that have been made to the selected remedy, CDPHE and EPA believe that the revised remedy is protective of human health and the environment, complies with federal and state requirements, and is cost effective. In addition, the revised remedy utilizes permanent solutions to the maximum extent practicable for the SITE. PUBLIC PARTICIPATION ACTIVITIES For the last two years, CDPHE and EPA have discussed addressing the Big Five Tunnel discharge and the sediment with key stakeholders involved in the Clear Creek community, including the City of Idaho Springs, Clear Creek County, the Clear Creek Watershed Advisory Group, the Upper Clear Creek Watershed Association, the Colorado Department of Transportation, and various landowners. Minutes for the January 8 and February 12, 2004 Upper Clear Creek Watershed Association meetings include a notion passed and other general support for the project to pipe the Big Five Tunnel discharge to the ARGO Water Treatment Facility for treatment. The Responsiveness Summary for the OU 3 ROD includes numerous comments requesting treatment of more acid mine discharges. The Responsiveness Summary for the OU 3 ROD states that "[S]everal downstream water users voiced support for treatment of the Big Five tunnel by constructing a pipeline which would carry the tunnel discharge to the treatment unit which will be constructed for the Argo tunnel." CDPHE and EPA will continue to meet with stakeholders as the remedy moves forward. E