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DERR Ground Water and Hydrogeology Support

Photo showing the low-flow ground water sampling technique being used to fill a sample bottle for volatile organic compound analysis.

Volatile organic compound (VOC) ground water sample collection

Welcome to the DERR Ground Water and Hydrogeology Support page! If you have a question, please contact us at DERRCOGroundwater@epa.ohio.gov

The DERR Ground Water Group supports the investigation of ground water and hydrogeology at sites being investigated for cleanup of hazardous wastes and hazardous substances, including:

  • RCRA Subtitle C (hazardous waste) facilities
  • State-Lead Remedial Response sites
  • CERCLA (Superfund or NPL) sites and Federal Facilities
  • Ohio VAP and Brownfield properties 

Technical Guidance Manual

TGM

The DERR Ground Water Group maintains Ohio EPA's Technical Guidance Manual (TGM) for Hydrogeologic Investigations and Ground Water Monitoring. The TGM is shared among and supported by Ohio EPA's waste management and clean-up divisions (DERR, DMWM, DDAGW, DSW and DEFA). The TGM:

  • Provides guidance for investigating ground water and hydrogeology at waste facilities and contaminated sites
  • Facilitates the collection of accurate and precise data that represents site conditions
  • Promotes consistency across Ohio EPA's various regulatory programs
  • Informs the public of Ohio EPA’s science-based technical recommendations

Ohio EPA uses the TGM to support decisions regarding regulatory compliance. Except for the VAP, methods other than those described in the TGM may be used to satisfy Ohio EPA’s regulatory programs based on project circumstances or site-specific conditions. However, Ohio EPA may require a demonstration that the alternate methods generate data meeting regulatory requirements. Under the VAP, sampling activities investigating ground water contamination need to follow the TGM per OAC 3745-300-07(F)(6)(d)(viii)(b).

The TGM chapters are periodically updated and the most current versions are available under "Current TGM Chapters." The TGM also includes supplementary documents on specific technical issues, which are available under "Supplements." Previous versions are available under "Archived TGM Chapters."

Current TGM Chapters

  • Chapter 1: Introduction (see Archived TGM Chapters)*
  • Chapter 2: Regulatory Overview (see Archived TGM Chapters)*
  • Chapter 3: Characterization of Site Hydrogeology (April 2015): This chapter provides recommended methods for characterizing site hydrogeology when investigating ground water contamination. The chapter includes discussion of preliminary hydrogeological evaluations, field methods for sample and data collection, hydrogeological characterization techniques (including investigation of stratigraphy, description and classification of geological materials, evaluation of fractures in soil and bedrock, recognition of anthropogenic influence and evaluation of ground water occurrence), ground water use determination, and analysis and presentation of hydrogeological information.
  • Chapter 4: Pumping and Slug Tests (February 2018): This chapter provides recommendations for the design and performance of slug and pumping tests (aquifer tests), including quality assurance and quality control procedures and standardized approaches for data presentation. Topics include slug tests, single well pumping tests, multiple well pumping tests, drawdown data correction and data analysis. The applicability (advantages and disadvantages) of the various tests is discussed along with the testing requirements that should be considered before, during and after the performance of a test.
  • Chapter 5: Monitoring Well Placement (February 2022): This chapter provides recommendations for monitoring well placement, including factors to consider when placing wells, monitoring well network design, downgradient well placement and background well placement. The term "monitoring well placement" refers to the areal location of a well and the depth and length of its screened interval. Factors that should be considered when determining monitoring well placement include monitoring purpose, site hydrogeology, potential contaminant properties and potential anthropogenic influences.
  • Chapter 6: Drilling and Subsurface Sampling (October 2017): This chapter provides recommendations for drilling and sampling of boreholes. Important considerations when planning a drilling and subsurface sampling project include evaluating site-specific factors that will affect the choice of drilling method (hydrogeology, nature of contamination and investigation purpose/scope of work); determining which drilling method(s) are most appropriate given site conditions and project objectives; selecting the appropriate soil sampling method(s); implementing drilling and sampling activities; and selecting and implementing appropriate decontamination procedures.
  • Chapter 7, Monitoring Well Design and Installation (February 2008): This chapter presents information on the installation and construction of monitoring wells. Important considerations when designing, installing and constructing monitoring wells include whether single saturated interval wells or multiple saturated interval systems are most appropriate; the type of well casing and its diameter; the type of intake (screen with sand filter pack or open borehole); the type(s) of material (grout) used to backfill the annular space above the intake; the type of surface protective casing completion installed; well construction documentation; and well maintenance and rehabilitation. (Note: Chapter 15 provides information on the use of direct push technologies for drilling and monitoring well installation.)
  • Chapter 8: Monitoring Well Development, Maintenance, and Redevelopment (February 2009): This chapter presents information on monitoring well development, maintenance and redevelopment. Considerations for monitoring well development (and redevelopment) include (1) understanding the factors that affect well development efforts: hydrogeology, the well drilling method, well design and construction, the well’s intended use(s) and the presence of nonaqueous phase liquids (LNAPL and/or DNAPL); (2) development procedures, including predevelopment activities, development methods and development criteria; (3) well development documentation; and (4) the time interval between well development and ground water sampling. In addition to well development and redevelopment, performing regular monitoring well inspection and maintenance are important for proper well performance.
  • Chapter 9: Sealing Abandoned Monitoring Wells and Boreholes (September 2016): This chapter discusses sealing boreholes and decommissioned monitoring wells and provides recommendations for sealing (grouting) materials, project planning, field procedures, and documentation of sealing activities. Exploratory boreholes that are not completed as monitoring wells and decommissioned monitoring wells that are no longer needed should be properly sealed. Proper sealing prevents cross-connection and cross-contamination between aquifers and saturated zones; prevents degradation of ground water from surface contaminants; and restores the saturated zone or aquifer as close to its original condition as possible. In addition, proper sealing eliminates physical hazards associated with an unsealed boring or unneeded monitoring well and reduces the property owner’s potential for future liability.
  • Chapter 10: Ground Water Sampling (October 2020): This chapter describes recommended procedures for collecting ground water samples from monitoring wells. It includes discussion of factors influencing ground water quality, planning and preparation prior to sampling, types of sampling and purging equipment, field procedures, quality control sampling and field documentation to ensure that samples are representative of the ground water quality of the sampled aquifer or saturated zone. This chapter also discusses potential impacts that sampling activities may have on ground water sample integrity. In addition, this chapter provides limited information on the selection of ground water analytical methods and laboratory quality assurance.
  • Chapter 11: Soil Gas Monitoring For Site Characterization (August 2008): This chapter discusses the use of soil gas monitoring for site characterization. Important considerations for soil gas monitoring include survey design factors, including the chemical and biochemical properties of contaminants, site physical characteristics and meteorological conditions; sampling techniques and analytical methods, including active and passive sampling methods, surface flux chambers and headspace measurements; and data analysis techniques and data interpretation. Soil gas sampling and analysis can be a rapid and cost-effective approach for preliminary delineation of the spatial extent of volatile organic compound (VOC) contamination in the subsurface. The information obtained is often useful for developing effective soil and ground water sampling and analysis plans.
  • Chapter 12: Ground Water Quality Organization and Interpretation (February 2018): This chapter discusses the analysis and assessment of ground water data. Large amounts of ground water quality data can be generated during a hydrogeologic investigation or even a single ground water sampling event. Proper data analysis and assessment, including data validation, are necessary to provide the foundation for sound technical and regulatory decisions. Ground water data analysis requires an understanding of laboratory analytical methods and associated quality assurance/quality control (QA/QC); data validation; interpretive tools, including maps, graphs, statistical methods, modeling, and the application of professional judgment; and how ground water data packages should be organized and presented for regulatory submittals.
  • Chapter 13: Statistics for Ground Water Quality Comparison (see Archived TGM Chapters)**
  • Chapter 14: Ground Water Modeling (November 2007): This chapter presents ground water flow and contaminant fate and transport models, which are used to help understand and evaluate hydrogeologic systems. Types of models and the general protocols for utilizing, selecting, developing, evaluating/validating, and documenting models are discussed. Models are simplified representations or approximations of real hydrogeological systems and may incorporate one or more physical or chemical processes operating within ground water and/or the overlying unsaturated (vadose) zone. The purpose of modeling varies widely, and the approach used may depend on site-specific needs, understanding of the hydrogeology, availability of input data, the expectation and use of the model results and/or other criteria.
  • Chapter 15: Direct Push Technologies for Soil and Ground Water Sampling (September 2016): This chapter discusses the use of direct push (DP) technologies to collect soil and ground water samples for subsurface investigations and chemical analyses and to provide other site characterization data. Topics include the equipment (rigs) used for mechanically advancing DP rods and tools; DP soil samplers and soil sampling; DP ground water samplers and ground water sampling, including the use of DP-installed monitoring wells; and specialized measurement and logging tools, including geotechnical, geophysical, hydrogeological, geochemical and soil gas sampling instruments. The chapter does not discuss manual sampling with hand-driven probes.
  • Chapter 16: Application of Geophysical Methods for Site Characterization (August 2008): This chapter discusses the use of geophysical methods for site characterization. Surface geophysical methods discussed include ground penetrating radar, electromagnetics, direct current resistivity, spontaneous potential, seismic refraction/reflection, metal detection, magnetometry and gravimetry. Down-hole (borehole or well) geophysical methods discussed include nuclear logs (natural gamma, gamma-gamma/density and neutron-neutron/porosity), electrical logs (induction, resistivity, single-point resistance, spontaneous potential and acoustic) and physical logs (temperature, fluid conductivity, fluid flow and caliper).

*The TGM no longer includes Chapters 1 and 2. See the DDAGW, DERR and DMWM web pages for Ohio EPA's program-specific ground water rules and guidance.

**The TGM no longer includes Chapter 13. Refer to U.S. EPA's Statistical Analysis of Groundwater Monitoring Data at RCRA Facilities-Unified Guidance, March 2009 for ground water statistical guidance.

TGM Supplements

Archived TGM Chapters

Ohio EPA provides previous versions of the TGM chapters for reference, e.g., if a previous version of a chapter is needed to evaluate compliance with a former rule.

  • Chapter 3: Characterization of Site Hydrogeology, Revision 1 (October 2006, archived April 2015): This chapter provides recommended methods for characterizing site hydrogeology when investigating ground water contamination. The chapter includes discussion of preliminary hydrogeological evaluations, field methods for sample and data collection, hydrogeologic characterization techniques (including investigation of stratigraphy, description and classification of geological materials, evaluation of fractures in soil and bedrock, recognition of anthropogenic influence and evaluation of ground water occurrence), ground water use determination, and analysis and presentation of hydrogeological information.
  • Chapter 4: Pumping and Slug Tests, Revision 1 (December 2006, archived April 2015): This chapter provides recommendations for the design and performance of slug and pumping tests (aquifer tests), including quality assurance and quality control procedures and standardized approaches for data presentation. Topics include slug tests, single well pumping tests, multiple well pumping tests, drawdown data correction and data analysis. The applicability (advantages and disadvantages) of the various tests is discussed along with the testing requirements that should be considered before, during and after the performance of a test.
  • Chapter 5: Monitoring Well Placement, Revision 1 (November 2007): This chapter provides recommendations for monitoring well placement, including factors to consider when placing wells, monitoring well network design, downgradient well placement and background well placement. The term "monitoring well placement" refers to the areal location of a well and the depth and length of its screened interval. Factors that should be considered when determining monitoring well placement include monitoring purpose, site hydrogeology, potential contaminant properties and potential anthropogenic influences.
  • Chapter 6: Drilling and Subsurface Sampling, Revision 1 (April 2007, archived October 2017): This chapter provides recommendations for drilling and sampling of boreholes. Important considerations when planning a drilling and subsurface sampling project include evaluating site-specific factors that will affect the choice of drilling method (hydrogeology, nature of contamination and investigation purpose/scope of work); determining which drilling method(s) are most appropriate given site conditions and project objectives; selecting the appropriate soil sampling method(s); implementing drilling and sampling activities; and selecting and implementing appropriate decontamination procedures.
  • Chapter 8: Monitoring Well Development, Maintenance and Redevelopment. Revision 1 (February 2004, archived February 2009): This chapter presents information on monitoring well development, maintenance and redevelopment. Considerations for monitoring well development (and redevelopment) include (1) understanding the factors that affect well development efforts: hydrogeology, the well drilling method, well design and construction and the presence of nonaqueous phase liquids (LNAPL and/or DNAPL); (2) development procedures, including predevelopment activities, development methods and development criteria; and (3) well development documentation. In addition to well development and redevelopment, performing regular monitoring well inspection and maintenance are important for proper well performance.
  • Chapter 9: Sealing Abandoned Monitoring Wells and Boreholes, Revision 2 (October 2009, archived September 2016): This chapter discusses sealing boreholes and decommissioned monitoring wells and provides recommendations for sealing (grouting) materials, project planning, and field procedures. Exploratory boreholes that are not completed as monitoring wells and decommissioned monitoring wells that are no longer needed should be properly sealed. Proper sealing prevents cross-connection and cross-contamination between aquifers and saturated zones; prevents degradation of ground water from surface contaminants; and restores the saturated zone or aquifer as close to its original condition as possible. In addition, proper sealing eliminates physical hazards associated with an unsealed boring or unneeded monitoring well and reduces the property owner’s potential for future liability.
  • Chapter 9: Sealing Abandoned Monitoring Wells and Boreholes, Revision 1 (February 2005, archived October 2009): This chapter discusses sealing boreholes and decommissioned monitoring wells and provides recommendations for sealing (grouting) materials, project planning, and field procedures. Exploratory boreholes that are not completed as monitoring wells and decommissioned monitoring wells that are no longer needed should be properly sealed. Proper sealing prevents cross-connection and cross-contamination between aquifers and saturated zones; prevents degradation of ground water from surface contaminants; and restores the saturated zone or aquifer as close to its original condition as possible. In addition, proper sealing eliminates physical hazards associated with an unsealed boring or unneeded monitoring well and reduces the property owner’s potential for future liability.
  • Chapter 10: Ground Water Sampling, Revision 2 (May 2012, archived October 2020): This chapter describes recommended procedures for collecting ground water samples from monitoring wells. It includes discussion of factors influencing ground water quality, planning and preparation prior to sampling, types of sampling and purging equipment, field procedures, quality control sampling and field documentation to ensure that samples are representative of the ground water quality of the sampled aquifer or saturated zone. This chapter also discusses potential impacts that sampling activities may have on ground water sample integrity. In addition, this chapter provides limited information on the selection of ground water analytical methods and laboratory quality assurance.
  • Chapter 10: Ground Water Sampling, Revision 1 (February 2006, Archived May 2012): This chapter describes recommended procedures for collecting ground water samples from monitoring wells. It includes discussion of factors influencing ground water quality, planning and preparation prior to sampling, types of sampling and purging equipment, field procedures, quality control sampling and field documentation to ensure that samples are representative of the ground water quality of the sampled aquifer or saturated zone. This chapter also discusses potential impacts that sampling activities may have on ground water sample integrity. In addition, this chapter provides limited information on the selection of ground water analytical methods and laboratory quality assurance.
  • Chapter 15: Direct Push Technologies for Soil and Ground Water Sampling (February 2005, archived September 2016): This chapter discusses the use of DP technology to collect soil and ground water samples for subsurface investigations and chemical analyses and to provide other site characterization data. Topics include the equipment (rigs) used for mechanically advancing DP rods and tools; DP soil samplers and soil sampling; DP ground water samplers and ground water sampling, including the use of DP-installed monitoring wells; and specialized measurement and logging tools, including geotechnical, geophysical, hydrogeological, geochemical and soil gas sampling instruments. The chapter does not discuss manual sampling with hand-driven probes.
  • 1995 TGM (archived February 2004, contains all original chapters): This manual provides technical guidance for performing hydrogeological investigations and ground water monitoring at sources of ground water contamination. In general, this document is designated for sites or facilities regulated by Ohio EPA and is intended to aid the regulated community in implementing technically sound ground water investigations that meet Ohio EPA’s regulatory requirements. The organization follows the general order of tasks that are performed for a ground water investigation. Chapter 1 provides an introduction and Chapter 2 is an overview of Ohio EPA’s regulatory authority. Chapters 3 and 4, address methods for investigating site hydrogeology. Chapters 5 through 9 cover procedures for monitoring well placement, drilling, construction, development and abandonment. Chapter 10 provides recommended methods for ground water sampling and analysis. Chapter 11 discusses supplemental methods that may be helpful for subsurface characterization or ground water quality determination. Chapter 12 includes data organization and interpretation, Chapter 13 addresses statistical comparisons and Chapter 14 discusses ground water modeling.

Monitoring Wells

Ohio Technical and Regulatory Guidance

Ohio EPA's TGM provides monitoring well installation and sealing guidance to help the regulated community comply with Ohio's monitoring well regulations.

TGM Chapters for Monitoring Well Installation, Maintenance and Sealing

Ohio Groundwater Association (formerly State Coordinating Committee on Ground Water)

The Ohio Groundwater Association (OGWA) is a division of  the Water Management Association of Ohio. It includes ground water technical or management staff from seven state agencies, two federal agencies and The Ohio State University Extension office. The OGWA promotes the implementation of a statewide ground water protection and management program, and as the former State Coordinating Committee on Ground Water (Ohio Water Resources Council subcommittee), has published the following guidance for monitoring wells in Ohio:

Ohio EPA Monitoring Well Rules

DDAGW Water Well Standards

  • OAC Rule 3745-9-03 for monitoring wells requires that damaged monitoring wells be repaired or sealed, and that monitoring wells that are no longer used shall be sealed using guidance from the TGM or other standards adopted by the director. These requirements apply not only to monitoring wells installed for Ohio EPA's regulatory programs, but any monitoring well or test boring that penetrates a aquifer or other saturated zone in Ohio for any purpose.

RCRA Monitoring Well Rules

  • OAC Rule 3745-54-15 applies to Final Standards ground water monitoring systems and discusses monitoring equipment (including wells), maintenance, and inspection requirements.
  • OAC Rule 3745-54-97 applies to Final Standards ground water monitoring systems and discusses the number, location, depth, construction and maintenance of monitoring wells.
  • OAC Rule 3745-65-91 applies to Interim Standards ground water monitoring systems and discusses the number, location, depth, construction, and maintenance of monitoring wells.

VAP Monitoring Well Rules

  • OAC Rule 3745-300-07, Phase II Property Assessment applies to monitoring wells installed for VAP investigations and incorporates Ohio EPA's TGM by reference. The rule discusses monitoring well location, depth, construction and maintenance and provides construction criteria for wells installed to perform aquifer yield testing.
  • OAC Rule 3745-300-11(B), Remediation, Compliance with Other Laws requires a VAP property owner to comply with OAC Rule 3745-9-03 for well maintenance and sealing and ODNR requirements for monitoring wells (submission of well log and well sealing reports).

Remedial Response Program Monitoring Well Requirements

  • Ohio EPA requires responsible parties to investigate and clean-up contamination at remedial response sites through findings and orders issued by the Director (DFFOs) under Ohio Revised Code Sections 3734.13, 3734.20, 6111.03, and 3745.01, or through judicial consent decrees These DFFOs and consent decrees typically include reference to the TGM as a technical guidance with respect to ground water monitoring and sampling activities, including the installation, maintenance and decommissioning of monitoring wells. (The TGM is also applicable at U.S. EPA National Priority List and Federal Facilities CERCLA clean-up sites and Brownfields.)

ODNR Monitoring Well Rules

The Ohio Division of Natural Resources ODNR requires that well logs be submitted for all newly installed monitoring wells and that well sealing reports be submitted for all decommissioned monitoring wells. The person who installs or seals a monitoring well is responsible for filing the well log and well sealing report for the well owner (the property owner).

RCRA

RCRA Rules for Ground Water Protection, Permitted (Part B) Facilities

RCRA Rules for Ground Water Monitoring, Interim Status Facilities

  • 3745-65-90, Applicability  Ground Water Monitoring
  • 3745-65-91, Ground Water Monitoring System
  • 3745-65-92, Sampling and Analysis
  • 3745-65-93, Preparation, Evaluation and Response
  • 3745-65-94, Recordkeeping and Reporting  Ground Water Monitoring

RCRA Ground Water Technical Guidance Compendium

Ground Water Data Reporting

Ohio EPA provides the following templates and guidance to help facilities successfully submit ground water monitoring data:

  • The documents are intended for Supplementary Annual Groundwater Reports, but may be used for other ground water data submittals (Semiannual, Quarterly, Non-Periodic).
  • Submit Supplemental Annual Report Sections 1 through 5 in the Excel workbook template. A completed example is provided. Follow the format provided.
  • Submit Supplemental Annual Report Sections 6 through 10 as necessary depending upon monitoring program requirements.
  • Use the Master Parameter List for naming the constituents in the Excel workbook.
  • U.S. EPA requires data validation on 10% of the ground water data submitted. Tier I and Tier II data validation guidance are located under Cleanup under RCRA  Corrective Action and Closure (Data Validation tab/drop-down menu). Ground water data submitted must include sufficient information for Ohio EPA staff to complete the Tier I checklist.

Supplemental Annual Groundwater Reports Templates and Guidance

Statistical Guidance

Ohio EPA recommends use of the following guidance for the statistical analyses of ground water data, including the preparation of work plans, evaluation of data and reporting of results for the RCRA Final Standards and Interim Status rules:

Closure Plan and Corrective Action Guidance

For additional information on RCRA Closure and Corrective Action, including data validation resources, please see Cleanup under RCRA  Corrective Action and Closure.

Alternate Concentration Level (ACL) Guidance

U.S. EPA has developed an ACL guidance for RCRA Corrective Action sites. This document is provided with Ohio EPA's ACL guidance (below) to assist Ohio EPA staff and the regulated community in preparing and reviewing ACL demonstrations submitted to meet the requirements of OAC Rule 3745-54-94.

Remedial Response

Ohio EPA Guidance Documents and Resources

Ohio EPA requires responsible parties to investigate and clean-up contamination at Remedial Response (state-lead CERCLA or Superfund) sites through findings and orders issued by the Director (DFFOs) under Ohio Revised Code Sections 3734.13, 3734.20, 6111.03, and 3745.01, or through judicial consent decrees. These DFFOs and consent decrees typically include reference Ohio EPA's Technical Guidance Manual for Hydrogeologic Investigations and Ground Water Monitoring (TGM) as guidance for site investigation and clean-up activities. In addition, Remedial Response ground water guidance documents and resources are available on the DERR Guidance page. The following guidance documents may be helpful for ground water investigations and remediation at Remedial Response sites:

CERCLA (Superfund)

U.S. EPA Guidance Documents and Resources

The TGM is also applicable to CERCLA (Superfund or NPL) sites and Federal Facilities where Ohio EPA supports U.S. EPA's site investigation and clean-up activities. In addition, the following guidance documents and resources are available:

VAP

VAP Rules for Ground Water Monitoring and Remediation

VAP Technical Guidance Compendium

VAP ground water guidance is available on the DERR Guidance page in the VAP Technical Guidance Compendium.

Soil Leaching to Ground Water Guidance

Chemical Information Database and Applicable Regulatory Standards (CIDARS)

Ground Water Remediation Guidance

General

Monitored Natural Attenuation (MNA)

Useful Links

Links to Regulatory and Technical Resources

Links to Professional and Training Resources