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Midwest US

Coal Ash Groundwater Monitoring and Compliance

Our client’s five coal-fired power plants have historically used impoundments/landfills to contain their Coal Combustion Residuals (CCR). Over 10 of the CCR units are regulated under the Federal CCR Rule and are required to perform groundwater monitoring. Most of these units are also subject to staterequired monitoring, corrective action, and reporting. The client’s objectives are to:

  • Collect groundwater samples representative of background groundwater quality data from over 150 monitoring wells.
  • Manage and evaluate background groundwater sampling data in accordance with 40 CFR 257.93.
  • Initiate a detection monitoring program in accordance with 40 CFR 257.94.
  • Investigate data that may result in statistically significant increases (SSI), and determine if the SSI may be from a non-CCR source.
  • Develop and submit annual groundwater monitoring and corrective action reports in accordance with 40 CFR 257.90(e) and state regulations.
  • Collect and evaluate groundwater, pore water, and surface water data to support state compliance.


The client installed a groundwater monitoring well network and began implementing a sampling and analysis plan (SAP) for each of the CCR units. TRC provided strategic advisory services for CCR groundwater compliance and managed the implementation of the CCR Rule for groundwater monitoring.


Since 2017, TRC has managed the groundwater monitoring program, coordinated with subcontractors, collected background groundwater quality data from the monitoring wells, managed the data in EQuIS®, performed data QA/QC, developed preliminary and final statistical evaluation plans using groundwater data following the RCRA Unified Guidance, and evaluated groundwater data trends. TRC developed conceptual site models CSMs for each site to support management decisions related to impoundment closures and longer term risk management. TRC is also supporting compliance with state requirements, including evaluating groundwater data to determine the potential need for corrective action under the state cleanup program.


Background data collection was completed by October 17, 2017, with the groundwater monitoring well networks and planned statistical evaluation certified by a professional engineer. TRC has developed statistical evaluation plans for each unit in accordance with the performance standards of the CCR Rule. Groundwater data collected since October 1, 2017 continues to be evaluated to determine if SSI(s) are observed, and appropriate response measures are being implemented. Annual groundwater monitoring reports are being submitted as requiresd by the CCR Rule in addition to monitoring and reporting to comply with newly promulgated state-specific CCR regulations.


TRC is also evaluating groundwater quality and geochemical indicators to support alternative source demonstrations (ASDs), and has prepared Assessment of Corrective Measures (ACM) reports as needed. TRC is performing additional investigation and data evaluation activities to support final remedy selections and closure demonstrations while managing a variety of ongoing groundwater monitoring programs.



Confidential Client

Project Location

Midwest US

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