expanded as needed throughout the project, and used to distribute information and meeting announcements. Comments received regarding the Proposed Remedial fiction Plan [PRAP) have been addressed and are documented in the Responsiveness Summary (Exhibit D). I VIII. SELECTED REMEDY The selected remedy consists of Source Alternative 2 and Marsh Alternative 48 which would incorporate the final design plans for the leachate transfer system and the Cap System. The major elements of the proposed remedial program can be summarized as follows: o Construction of an engineered capping system to isolate the landfilled wastes from rainfall and human contact. This cap system will extend over both the original fill area and the Ballfield cell. o Construction of an active landfill gas collectdon system to prevent exposure to landfill emissions. This syetem will include active removal of landfill gases with a gas flare to destroy the volatile components of the gas. o Construction of a stormwater diversion system on the site. This system will collect clean, precipitation induced rufloft, will eliminate any detrimental discharge of sediments, and bypass the water around the waste mass for controlled discharges to the Hudson River and Croton Bay. . This o Construction of a leachate seepage collection system system will enclose the landfill perimeter at the toe of the cap. This system will collect and convey leachate to a series of pumping stations for permitted discharge to the sanitary sewer system. The system will have sufficient storage capacity to avoid discharging leachate to the sanitary sewer system during periods of high flows to the sewers (storm events). o Environmental monitoring to determine the effettiveness of the remedial program. Groundwater, surface waters, leaghate, landfill gases, stormwater discharges and marsh sediments will all be subjected to a periodic monitoring program designed to detect any changes in the effectiveness of the remedial program. Groundwater and surface water parameters will include 6 NYCRR Part 360 baseline parameters annually and routine parameters quarterly at a minimum for the first five years. Subsequent monitoring may vary based on those results. The County must prepare and submit for NYSDOH and NYSDEC acceptance a complete plan for the operational, maintainance and monitoring activities, as *ell as long-term land uses planned for the landfill after construction. Monitoring of leachate quality will be performed monthly for the first several years.to assess any change in leachate quality which may impact the sewage treatment plant's ability t o treat it. Should the lcachate monitoring indicate a-change in leachate quality or the sewage treatment plant's pretreatment requirements chanae such that the leachate would exceed those pretreatment requir&ents, pretrqatment of the leachate will be implemented. o Imposition of deed restrictions which limit the future uses of the site to specific non-intrusive activities and restricts the rltilization of groundwaters beneath the site in accordance with the operational and maintenance programs to be developed during the Remedial Action. The estimated net present worth of the selected remedy described above is $33,370,000. This estimate includes $28,700,000 in capital cosks and $4,670,000 in present worth of recurring operational and maintenance costs for the 30 year post closure monitoring period. These estimates are based upon a combination of actual bid proposals from contractors and the projected annual operational costs. The transfer components and sections of the leachate collection system are already operating and the costs associated with these components are included in the above figure. The selected remedy represents the best technical and cost-eftective approach from among the assembled alternatives. It recognizes that this site was primarily a municipal landfill and has been inactive for 6 years without any significant remediation. It is readily constructed anti results in achievement of the remedial goals. The selected remedy is both protective of both human health and the environment and it recognizes the unique probleme presented with a landfill site which is as large as CPSL and contains such a heterogeneous waste mass. The selected remedy allows Westchester County to utilize the parcel upon completion for additional recreational opportunity as an extension of the existing park facility, thereby enhancing the prospects for continued compliance with Part 360. Future use of the site by residents should ensure that any signifiaant settlement of waste, which is the most likely reason for any signidicant leakage through the cap, will be noticed right away and could be qqickly remedied to maintain the cap's integrity. Deed restrictions will ensure that this future use will not result in unacceptable exposure to contaminants. Because this remedy will not allow for unlimited use and unrestricted exposure to wastes, within five years after completion of remedial action, a five year review will be conducted. This evaluation will be done to ensure that the remedy continues to provide adequate protection of human health and the environment. IX- DOCUMENTATION OF SIGNIFICANT CHANGES The remedy presented to the public in the