United States Army Corps of Engineers (USACE) Perspectives on the Current State of MMRP Practices

¹MMRP Geophysicist, USACE Environmental and Munitions Center of Expertise (EM CX)
²MMRP Geophysicist, USACE-EMCX
³MMRP Environmental Scientist, USACE-EMCX
⁴MMRP Geophysicist, USACE-EMCX
⁵MMRP Geophysicist, USACE-EMCX

Email: [email protected]

As a result of decades of live-fire testing and training, the Department of Defense (DoD) has a Military Munitions Response Program (MMRP) liability estimated to be over 11 billion dollars. Significant improvements in guidance, technology, and quality have been achieved over the last decade that have significantly improved project execution.

In this paper, the USACE EMCX provides their perspective on the current state of the industry to include discussions of guidance document updates, a focus on quality, one-pass advanced geophysical classification (AGC), remedial investigation characterization, and what they see in the future of MMRP.

It has been a good year for new guidance document issuances in the MMRP! The Office of the Secretary of Defense (OSD) and the U.S. EPA jointly signed the Munitions Response Quality Assurance Project Plan (MR-QAPP) Toolkit Module 2 for Remedial Action; the OSD published the Military Munitions Response Program Risk Management Methodology (RMM), and the U.S. Army Corps of Engineers published Engineer Manual 200-1-12 Conceptual Site Models (CSM). The MR-QAPP Toolkit Module 2: Remedial Action was developed to, “assist project teams in planning for the characterization and remediation of munitions and explosives of concern (MEC) using geophysical methods at [DoD] installations and formerly used defense sites (FUDS). [The MR-QAPP] employs the systematic planning process (SPP) to illustrate scientifically sound approaches to characterizing and remediating MEC at MRS in accordance with the Comprehensive Environmental Response, Compensation and Liability Act (CERCLA) as amended.” (OSD and USEPA, 2023)

The RMM was developed to be a tool to help project delivery teams fulfill the CERCLA requirement to complete a MEC risk assessment as part of the remedial investigation phase of CERCLA projects. RMM provides, “…a consistent process for understanding and evaluating risk at munitions response sites …[It] is a qualitative risk evaluation tool that project teams can use to facilitate discussions about cleanup and build consensus for risk management decisions at Munitions Response Sites (MRSs).  The RMM itself does not determine the level of risk at an MRS; it is only a tool to guide project team discussion about the level of risk.” (OSD, 2023)

The USACE Engineer Manual 200-1-12 was updated to “[provide] procedural guidance to develop [CSMs] for sites where [MEC], chemical warfare materiel (CWM), munitions constituents (MC), and/or hazardous, toxic, and radioactive waste (HTRW) are known or suspected to be present.” (USACE, 2023)

A new Army technical memorandum was released in 2022 titled “Minimum Separation Distance Reduction with Advanced Geophysical Classification” that allows AGC source size estimations to be utilized in reducing explosive safety distances, as appropriate. The technical memorandum also allows for reduced evacuation during explosives operations while maintaining all appropriate safety arcs.

Two guidance documents are planned for publication in 2024: an update to the USACE Engineer Manual (EM) 200-1-15, Technical Guidance for Military Munitions Response Actions, and the USACE Engineer Pamphlet (EP) 200-1-20, Establishing & Maintaining [Land Use Controls] for Environmental Actions [working title only]. The EM 200-1-15 will provide comprehensive updates to the planning, execution, and quality management of MEC response actions, and the revisions and updates will align this guidance document with the publications listed above. The EP 200-1-20 will similarly revise and update that guidance document to reflect DoD and USACE policies now in effect and to align its content with current best practices in planning and implementing land use controls on munitions response sites.

Focus on Quality

Geophysical classification is a broad term that has historically been used in various ways; however, AGC refers to a specific subset of multi-axis, multi-coil electromagnetic induction (EMI) sensors and methodologies used for munitions response that have been validated by the DoD Advanced Geophysical Classification Accreditation Program (DAGCAP). More generally, AGC refers to the process that measures the intrinsic properties of buried metallic objects to generate principal-axis polarizability decay curves which, in turn, allow for the classification of the buried metallic objects as targets of interest (TOIs) or non-target of interests (non-TOIs). The polarizability curves reflect the size, symmetry, material composition, and wall thickness of the buried metallic objects.

Until 2019, the general AGC approach was to detect an anomaly in an initial dynamic survey, then return to the anomaly to take a second EMI measurement for 30-70 seconds with an AGC sensor stationary over the anomaly. That approach to using AGC typically reduced the number of anomalies requiring expensive excavation by UXO specialists by between 85 and 93%, so the cost benefit of taking the second EMI measurement over all detected anomalies was significant. But over the past few years hardware vendors and researchers have developed a dynamic one-pass classification approach where the detection and classification phase is done in one data collection event greatly improving the cost benefits of using AGC. The first hardware to do so was successfully validated under DAGCAP in 2019 with other equipment manufacturers to offer their versions to follow. One-pass AGC approaches also bring higher quality data to the anomaly detection phase, which improves the fidelity of individual anomaly interpretations and further reduces overall project costs.

The MR-QAPP Toolkit Module 1 was published in December 2018 and revised in April 2020. It lays out a phased process that starts with identifying High Density (HD) and Low Density (LD) areas that could respectively be High Use Areas (HUAs) and Low Use Areas (LUAs) that could contain MEC. This approach builds on the use of Visual Sample Plan (VSP) to 1) design a geophysical transect survey to traverse and detect high concentrations of metal associated with munitions use or munitions disposal, and 2) to perform geostatistical analysis of anomaly density to identify HD areas potentially associated with munitions use.
In the last few years USACE has identified a need for better training in VSP and in how HD areas and HUAs are delineated. An HD area is defined as an area within an MRS where the anomaly density is above a critical density, where the critical (anomaly) density is a VSP input parameter defined in the MR-QAPP Toolkit Module 1 as, “the upper bound of acceptable anomaly density, i.e., the estimated, site-specific upper bound of anomaly density considered to be attributable to background (non-munitions-related) sources. It is the project-specific, user-defined value for anomaly density (inclusive of background) used to delineate [HD] areas from [LD] areas” (OSD and USEPA, 2020). A problem the EM CX has identified is that project teams often set the critical density at a very large number (e.g., hundreds or thousands of anomalies/acre above background). The impacts of too high of a critical density are twofold: it can lead to poorly defined HUA boundaries, and worse, the project team can fail to detect HUAs. A consequence to both is that it can result in significant errors in assessing explosives risks to the public. There are multiple potential causes for these issues: insufficient VSP and/or MR-QAPP training; a lengthy time between VSP training and project execution; incomplete, or rushed, analysis of preliminary characterization transect data in VSP; a lack of communication between all project delivery team members; or contracting methods that impede simple expansions to needed field work.
The EM CX recommends preliminary characterization data analysis in VSP be discussed during Systematic Planning Process (SPP) meeting 5. This discussion should focus on how anomaly density estimates are translated into HD and LD areas and on all the inputs that are used to generate those anomaly density estimates. These include, but are not limited to, the window diameter; variogram model and inputs used to fit to the data; how background anomaly density is defined; how the critical anomaly density is defined; and the minimum size of an HD area.
Often the only personnel involved in discussions of the VSP analysis are the contractor and government geophysicists, but the EM CX recommends the discussion include project managers, technical managers, UXO technicians, and risk assessors, because HUAs and LUAs may have different levels of risk and may ultimately have different selected remedial alternatives. Incorrect delineation of HUA and LUA boundaries may lead to inaccurate risk assessment determinations and incorrect assumptions, to include cost estimations, forming the basis of an MRS’s selected remedy. Including these additional team members and having a detailed and thorough discussion of each of the inputs and outputs fosters collaboration and buy-in to the risk attributed to each portion of an MRS, as well as the remedy selected to protect the public from that risk.
The EM CX has presented, both internally and to the NAOC, on the Remedial Investigation (RI) MEC characterization guidance contained in the EM 200-1-15, and on the methods for identifying HD areas using VSP. USACE will continue to monitor trends in the application of VSP to identify HD areas and in defining HUAs and will present those findings to the user community.

The EM CX continues to be forward looking, to incorporate lessons learned from across industry into its workflows, and to identify and resolve issues that may affect the munitions response program. At the top of the current issues list are the HUA/LUA delineation discussed above; identifying more robust procedures to delineate and remediate saturated response areas (i.e., areas with anomaly densities too high to reliably detect or classify individual sources); and implementing better methods to estimate source sizes from AGC data.

On the research side, the Strategic Environmental Research and Development Program (SERDP) and Environmental Security Technology Certification Program (ESTCP) have moved further past the land side and into the underwater side of munitions detection and classification. The last several years, SERDP and ESTCP have released statements of need for underwater research proposals as they attempt to address DoD’s underwater munitions environmental liabilities. Detection, classification, and location (DCL) are the primary research needs from a geophysical perspective (both EMI and acoustics); however, SERDP and ESTCP are also addressing underwater munitions burial and mobility, containment and recovery, and UXO penetration depth modeling.

The Office of the Secretary of Defense has formed an underwater workgroup with plans to implement some of the research on live site demonstrations. As part of that effort, DoD will be engaging with stakeholders through the Interstate Technology and Regulatory Council (ITRC) and the ESTCP Advisory Group. The focus in those two groups is twofold: the appropriate implementation and transfer of emerging research technology, and the development of appropriate MR-QAPP processes, measurement performance criteria, and measurement quality objectives for underwater munitions response actions. Alongside the implementation, the discussion of how DAGCAP will fit underwater munitions response will need to be addressed.

Office of the Assistant Secretary of Defense, 2023, Military Munitions Response Program Risk Management Methodology.

OSD and USEPA, 2020, Uniform Federal Policy for Quality Assurance Project Plans Munitions Response QAPP Toolkit Module 1: Remedial Investigation (RI)/Feasibility Study (FS) Update 1.

Office of the Deputy Secretary of Defense for Environment & Energy Resilience and U.S. Environmental Protection Agency, Federal Facilities Restoration and Reuse Office, 2023, Uniform Federal Policy for Quality Assurance Project Plans Munitions Response QAPP Toolkit Module 2: Remedial Action.

U.S. Army Corps of Engineers, 2023, Engineer Manual 200-1-12 Conceptual Site Models.