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1 <br />1 <br />1 <br />1 <br />1 <br />U I <br />1 <br />1 <br />1 <br />1 <br />1 <br />1 <br />1 <br />1 <br />1 <br />1 <br />1 <br />The City of Everett <br />The Floyd & Snider Team Everett Landfill/Tire Fire Site <br />site for discharge. The leachate collection system will also be inspected to verify that it is in <br />good repair and working effectively. These inspections will be coordinated with the site <br />inspections defined in Chapter 5 for the Direct Contact Pathway. <br />4.4 EVALUATION MONITORING <br />Evaluation Monitoring will collect data to supplement the current understanding of baseline <br />conditions for the shallow and deep aquifers. This information will define baseline conditions <br />against which Performance Monitoring results will be evaluated in order to assess seasonal and <br />long-term changes in groundwater quality that may result from future site development, remedial <br />actions, or local changes to groundwater recharge or discharge. Evaluation monitoring will also <br />support the selection of appropriate wells, analytes and cleanup levels for long-term <br />Performance and Confirmational Monitoring. <br />The Evaluation Monitoring period is designed to measure groundwater characteristics that will: <br />1. Evaluate existing conditions at new wells located upgradient to determine area <br />background concentrations and finalize cleanup levels. <br />2. Evaluate existing conditions at new wells located at the point of compliance using <br />standardized sampling procedures. <br />3. Establish a statistically significant database to determine existing contaminant <br />concentrations in each monitoring well. <br />4. Define groundwater gradients in the deep and shallow flow systems to select the best <br />long-term groundwater monitoring well network. <br />4.4.1 EVALUATION MONITORING PLAN <br />Results from previous groundwater sampling events at the site indicate overall groundwater <br />quality conditions. However, the sporadic frequency of previous sampling, inconsistencies of <br />sampling procedures and the low number of sampling events on all existing wells do not support <br />a statistical evaluation of trends or seasonal variations. The Evaluation Monitoring period will <br />provide a baseline understanding of groundwater quality conditions that will be used to evaluate <br />potential leachate impacts b groundwater and surface water, and the potential impact of pile <br />installation on the deep aquifer. <br />Evaluation Monitoring will consist of improvements to the groundwater monitoring well network, <br />water level monitoring, and quarterly water quality monitoring and reporting. A detailed <br />sampling and analysis plan (SAP) for Evaluation Monitoring will be developed in accordance <br />with the Scope of Work and Schedule, Exhibit D to the Consent Decree. <br />4.4.1.1 Monitoring Well Network Improvements <br />The existing groundwater monitoring well network does not adequately monitor the deep aquifer <br />point of compliance. Additionally, several existing wells are redundant, improperly installed, or <br />do not provide useful water quality or water elevation data for groundwater pathway monitoring. <br />Therefore, new wells and wells to be abandoned are included as a component of Evaluation <br />Monitoring. <br />docs jest phance M Everett LandfiMCP maker -final Compliance Monitoring and Contingency Plan <br />docslCompliance Monitoring PIan1CMCP 11-10-OO.doc <br />FINAL - March 2001 Page 4-3 <br />