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1 <br />Consent Decree Exhibit C <br />1 <br />1 <br />!1 <br />1 <br />1 <br />1 <br />1 <br />1 <br />1 <br />u <br />1 <br />1 <br />1 <br />1 <br />1 <br />4.0 Existing Conditions: Proposed Cleanup Action <br />The proposed cleanup action for existing conditions is applicable to current landfill conditions, <br />and to any portions of the Site that remain undeveloped in future conditions. <br />The proposed cleanup action for existing conditions includes all of the following: <br />• Control of landfill gas through compliance monitoring and contingency plans for <br />existing on -site buildings and representative off -site buildings. New perimeter <br />compliance monitoring probes will be installed. Perimeter landfill gas migration <br />controls will be installed if compliance monitoring demonstrates landfill gas is <br />migrating past the Site boundary. <br />• Groundwater protection through continued operation and maintenance of the existing <br />leachate collection system, maintenance of landfill cover, grading of surface <br />topography to control surface water and to reduce the production of leachate, and <br />institutional controls preventing groundwater withdrawal other than for leachate <br />collection or monitoring. <br />• Direct contact exposure prevention through maintenance of existing landfill cover, <br />erosion controls and access controls. <br />• Surface water pathway protection through maintenance of existing landfill cover and <br />perimeter ditch system, as well as site inspections for and appropriate responses to <br />possible leachate seeps, on -site ponding and existing stormwater system disruptions <br />due to differential settlement. <br />• Development and implementation of a Storm Water Pollution Prevention Plan <br />(SWPPP) for existing conditions. <br />• Associated institutional controls and comprehensive compliance monitoring. <br />4.1 PHYSICAL CHARACTERISTICS <br />The proposed cleanup action for existing conditions relative to the groundwater, surface water <br />and direct contact pathways would not change any physical characteristics of the existing Site. <br />A minimum of two feet of clean soil cover would be maintained on all portions of the, Site, <br />graded to a minimum of 2% slope, and vegetated. Surface water would not be allowed to pond <br />on the Site. The existing leachate collection system would remain operational. <br />Existing facilities operating on the Site will remain. Public access to the undeveloped portions of <br />the Site will be restricted, with fencing and signage. <br />New perimeter compliance landfill gas monitoring probes will be installed around the Site <br />boundary at a spacing of 200' along the western Site boundary and 100' along the northern Site <br />boundary. Perimeter landfill gas migration controls would be installed to control landfill gas if <br />proven necessary during perimeter compliance monitoring. These controls could either be <br />vertical extraction wells or a perimeter barrier trench. <br />FINAL - March 2001 4-1 Everett Landfill Tire Fire Site <br />Cleanup Action Plan <br />1 <br />