Coal_Combustion_Residuals

Coal Combustion Residuals Reducing Risk with Legally Defensible Decision Support Tools

Since 1974, INTERA has specialized in developing legally defensible groundwater flow and contaminant transport models, human health and ecological risk assessments, and post-closure waste disposal facility performance assessments (PAs). These tools enable the prediction and quantification of future risks (human health and ecological) resulting from the fate and transport of contaminants in the subsurface (vadose zone and groundwater), and serve as the technical basis for a legal defense in the event of a lawsuit. Final Rule: Disposal of Coal Combustion Residuals from Electric Utilities In April 2015, EPA finalized national regulations to provide a comprehensive set of requirements for the safe disposal of coal combustion residuals (CCR). These regulations are “self-implementing”—a facility must comply with them without any action by a regulatory agency. Therefore, enforcement of the requirements will be through citizen lawsuits (or by States acting as citizens). Under this rule, owners must demonstrate: Compliance with groundwater protection standards Source control Protection of human health and the environment Removal of contaminated material from the environment INTERA brings the expertise to help meet all these rule requirements and manage the high degree of risk uncertainty associated with civil lawsuits.

| Coal Combustible Residuals Management | Risk Reduction At CCR sites, risk reduction is almost entirely based on developing and maintaining legally defensible data and applying decision tools to support remediation and closure decisions. INTERA offers a suite of tools that include: Groundwater modeling Human health and ecological risk assessments Geochemical expertise and modeling to develop and defend background concentration cleanup standards Information analytics to facilitate communication and provide data transparency Risk reduction for our clients is a direct outcome from gaining access to the highest quality technical professionals and the advice that comes from the unique way we think about, and solve, complex technical and management challenges. INTERA’s staff consists of 175 geoscientists and engineers specializing in groundwater modeling, risk assessments, PAs, geochemistry, GIS, and application programming. Over 75% of our staff have advanced degrees, including 30% with PhDs. Many of our senior technical staff members are recognized experts in their respective fields and routinely provide litigation support on cases involving environmental contamination and water resources management issues. We also offer proven modeling tools and techniques that have been honed through continuous application and improvement over our 42-year history. INTERA’s depth of technical resources and years of corporate history provide clients with shared lessons learned/best practices, and proven groundwater modeling codes and tools to support making legally defensible remediation and closure decisions. Additional details on INTERA’s key areas of expertise to help reduce the risks associated with CCR sites are provided in the next pages.

Groundwater Modeling Developing and applying numerical models and other quantitative decision support tools have been core competencies of INTERA since our founding in 1974. Under contracts with the United States Geological Survey and Sandia National Laboratories, we developed some of the first public domain groundwater flow and transport modeling simulators. In addition to the high-level technical expertise needed to develop new modeling codes and tools, our geoscientists and engineers apply, and adapt to meet specific project requirements, many of the commonly used commercial codes (e.g., MODFLOW, GMS). Our modeling capabilities include: Simulation of contaminant flow and transport Definition of regulatory boundaries and remediation goals Identification of data gaps and guidance for additional data collection Uncertainty analysis and assessment of present and future risk Evaluation of remedial strategies and technologies Design and optimization of remedial systems and monitoring networks Analysis of contaminant sources to determine cleanup cost liability Evaluation of chemical interaction of dissolved organic and inorganic constituents One of the challenges of environmental impact While many companies provide modeling services, INTERA offers modeling investigations, and the subsequent development of an expertise. Numerical modeling is the technological capability on which our effective and efficient remedial strategy, is determining the company was founded over 40 years ago. validity of the conceptual site model. To help meet this challenge, INTERA is a leader in using groundwater flow and contaminant transport models to: Test the conceptual site model in a dynamic setting Provide insight for identifying critical data gaps in the current understanding of the site setting Serve as a quantitative basis for risk evaluations Anticipate foreseeable future conditions Compare remedial and mitigation alternatives

| Coal Combustible Residuals Management | Human Health and INTERA brings the expertise needed to conduct technically-defensible Ecological Risk Assessment risk assessments to demonstrate protection of human health and the environment and meet the source control requirement defined by EPA. Based on the site-specific nature and extent of contamination, and transport model results, we perform human health and ecological risk assessments to support the remedial/regulatory decision process. This starts with a conceptual site model, where all human health and ecological receptors are identified. The exposure risk for each identified hypothetical receptor is evaluated with the identified exposure scenarios. Additionally, we are able to integrate contaminant transport models into the human health and ecological risk assessment calculations to simulate the exposure risk associated with different remedial alternatives. This conceptual site model (risk assessment and contaminant transport model) is used to demonstrate protection of human health and the environment, and source control as required by the EPA. Geochemistry Based on the site-specific nature and extent of contamination, and transport model results, we perform human health and ecological risk assessments to support the remedial/regulatory decision process. This starts with a conceptual site model, where all human health and ecological receptors are identified. The exposure risk for each identified hypothetical receptor is evaluated with the identified exposure scenarios. Additionally, we are able to integrate contaminant transport models into the human health and ecological risk assessment calculations to simulate the exposure risk associated with different remedial alternatives. This conceptual site model (risk assessment and contaminant transport model) is used to demonstrate the protection of human health and the environment, and source control as required by the EPA.

Information Analytics INTERA has a long history of communicating project results to clients, regulators, the general public, and other interested stakeholders. To facilitate these communications, our expertise includes developing GIS and web-based applications to view site characteristics and data, generate maps and cross-sections, and present the results of modeling analyses. Since nearly every project requires the analysis and management of large volumes of data, we are also adept at using GIS as a means of storing, organizing, managing, analyzing, and sharing both spatial and non-spatial information. INTERA designs and creates geodatabases that meet the exact functional requirements of a project, focusing on scalability, reliability, and security. Transparency is also one of the key requirements of the CCR regulations. INTERA has developed tools that provide detailed spatial analysis capability and workflow for site GIS activities, particularly in the areas of modeling, engineering analysis, and regulatory reporting. We also have developed web-based GIS tools to enable users, including the general public, to view the environmentally-impacted areas around a site and the methods and technologies being used to address these impacts. We have developed web-based tools that incorporate embedded maps to show the live content of a figure in real time, maps with time-series data to show the monitored constituents in one or more wells, maps with subsurface geology data to show the elevation profiles and the wells, and maps with contaminant plume data. Proven Solutions Representative examples of our solutions to help minimize environmental liabilities and risks at CCR and other sites are provided below and on the next page. ■ Independent Peer Review of Groundwater Flow and Contaminant Transport Models for Use at Coal Combustion Residue Sites In support of the Electric Power Research Institute’s (EPRI) efforts to develop lessons learned for CCR pond simulations, provide a generic review and critique protocol, and prepare a model assessment guidance document for utility project managers, INTERA performed third party, subject matter expert review of eight groundwater flow and transport models. These models were developed using MODFLOW/MT3DMS) and applied at Duke Energy CCR ponds. Groundwater transport modeling is required at many ash pond sites due to the strict closure and monitoring requirements in the CCR rule. Our activities included: reviewing the model reports and input/output files; performing model runs with the supplied input files to test and ensure consistency of results; conducting meetings with the model developers (University of North Carolina Charlotte and Clemson University) and Duke Energy to discuss the models and resolve any questions, followed by further review and testing; and preparing technical memos to document the review and comments on the application and interpretation of each model.

| Coal Combustible Residuals Management | ■ Groundwater Characterization at Multiple Coal Combustion Residue Sites For two confidential clients, INTERA is providing data analyses, modeling, and regulatory support services as part of evaluating potential impacts to groundwater at several CCR sites. The overall scope includes groundwater characterization, through a detailed review of existing hydrogeologic, groundwater quality, and geological data (e.g., boring logs, cross sections, aquifer tests, etc.), identification of data gaps, statistical analysis of background concentrations, and development and implementation of groundwater models to evaluate flow and transport in the vicinity of CCR sites. ■ Modeling, Risk Assessments, and Web- Based Applications for Environmental Restoration of the U.S. Department of Energy’s Hanford Site, WA INTERA is providing data analyses, modeling, risk assessment, and strategic regulatory support services for the safe and compliant environmental cleanup of the Hanford Site’s Central Plateau and River Corridor areas. The cleanup of this former plutonium production facility and associated operations represents the largest environmental restoration project in the U.S. We develop risk-informed decision support tools to define preliminary remediation goals; evaluate, design, and optimize remediation systems; guide future site characterization efforts; and communicate site risks to stakeholders that include state and federal regulators. We have developed tools that are widely used to facilitate the communication of groundwater flow and transport results, risk assessment results (Dose Explorer), quality assurance, and the data quality objective (DQO) process. We have also developed tools and prepared web-delivered annual reports for the groundwater system and the pump-and-treat operations that allow stakeholders to query underlying data, create charts and geologic cross sections, and display results of complex analyses.

INTERA is an employee-owned geosciences and engineering consulting firm. As a medium-sized company, we focus on excelling in our key areas of expertise. Our people, our commitment, and our solutions are what differentiate INTERA from other consulting firms. EXPERT PEOPLE. INTERA’s technical staff members are some of the most talented in their respective fields. Our high-level of expertise, combined with practical hands-on experience, enables us to deliver technically-sound and cost-effective services. EXCEPTIONAL COMMITMENT. Not only are we fully committed to working safely, producing reliable results, and exceeding client expectations and requirements on projects, but our commitment extends to the issues and challenges that we solve. We work to protect the environment, find ways to sustainably use water and other natural resources, and safely isolate radioactive and other industrial wastes because these issues are important to us, personally. EXCELLENT SOLUTIONS. Talented people that are totally committed to client service and the work they are doing produce excellent solutions. At INTERA, we work diligently every day to achieve our vision of Delivering Excellence with Every Solution. To find out more about our services and solutions, please visit us at: .com For more informaƟon email: [email protected] Or visit us at www.intera.com California | Colorado | Florida | Hawaii | Indiana | New Mexico | Texas | Washington | France | Switzerland