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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 />1 <br />1 <br />1 <br />1 <br />1 <br />1 <br />water level monitoring only to show that compliance criteria for the shallow aquifer, based on <br />hydraulic control through operation of the leachate collection system, is being met. <br />Demonstration of hydraulic control will occur by monitoring water levels to show that hydraulic <br />gradients are toward the leachate collection system, indicating no shallow aquifer discharge to <br />surface water. Results will be submitted to Ecology annually. <br />Semi-annual performance monitoring of the deep aquifer will involve water quality monitoring. <br />Results will be submitted to Ecology annually. Exceedances of groundwater cleanup standards <br />in the deep aquifer at the point of compliance will first be verified with additional monitoring. If <br />the exceedance occurs in the re -sample, quarterly monitoring of that well will occur. <br />Contingency plan measures will be triggered if the exceedance continues or if analyte <br />concentrations are statistically significant as described in the CMCP. <br />Confirmational monitoring will occur semiannually for a minimum of ten years following <br />performance monitoring to confirm the long-term effectiveness of the cleanup action. <br />Confirmational monitoring of the shallow aquifer will involve water elevation monitoring only, as <br />described for performance monitoring. Reports to Ecology will be submitted on a bi-annual <br />basis. <br />If an exceedance is confirmed during compliance monitoring, the contingency plan will require <br />an evaluation of potential sources of the exceedance and will involve submitting a contingency <br />investigation plan to Ecology for review and approval. Results of that investigation will identify <br />implementation measures to address the exceedance, such as increasing leachate pumping or <br />reducing water infiltration. <br />4.2.3 Direct Contact Compliance Monitoring and Contingency Plan Objectives <br />Inspections of the entire Landfill/Tire Fire Site will occur on a quarterly basis. The objective of <br />the inspection is to identify and record areas of the cap/cover and Site security that have been <br />compromised and require repair. Immediate notification of problem areas, and the <br />corresponding Inspection Form record, will trigger contingency measures to address the <br />problem area. <br />4.2.4 Surface Water Compliance Monitoring and Contingency Plan Objectives <br />Compliance monitoring of water quality in the perimeter ditches will occur for a minimum of <br />three years to confirm whether Site runoff is exceeding cleanup levels for monitored parameters <br />at the point of compliance. Currently available data is not sufficient to determine whether landfill <br />runoff is causing a water quality violation or not, nor determine the extent of such a potential <br />violation. If additional monitoring determines that landfill runoff is affecting ditch surface water <br />quality above cleanup levels, contingency measures will be implemented to remedy this <br />problem. Compliance monitoring will include semi-annual samples collected during the summer <br />(dry season) and winter (wet season), from both background, downstream and compliance point <br />locations. The parameters to be tested will include the metals arsenic, cadmium, copper, lead, <br />nickel, and zinc. <br />FINAL - March 2001 4-3 Everett Landfill Tire Fire Site <br />Cleanup Action Plan <br />1 <br />