OLEM Directive Number 9200.1-166
Office of Superfund Remediation and Technology
innovation, and Office of Research and
Development
Sediment Assessment and Monitoring Sheet (SAMS)
Adaptive Site Management - A Framework for
Implementing Adaptive Management at Contaminated
Sediment Superfund Sites
v>EPA
United States
Environmental Protection
Agency
ADAPTIVE SITE MANAGEMENT PLAN
\ \ i / /
• Conceptual Site Model Refinement
• Stakeholder Engagement
June 2022
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Adaptive Site Management - A Framework for Implementing Adaptive Management at Contaminated Sediment Superfund Sites
Table of Contents
Preface II
Contact Info II
Statement of Purpose 1
Introduction to Adaptive Site Management at Superfund Sediment Sites 1
Adaptive Site Management Framework 4
Developing an Adaptive Site Management Plan 5
Implementing an Adaptive Site Management Plan 13
References 15
Figures
Figure 1. Framework for Adaptive Site Management Plan 14
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Adaptive Site Management - A Framework for Implementing Adaptive Management at Contaminated Sediment Superfund Sites
PREFACE
This fact sheet was prepared by the U.S. Environmental Protection Agency (EPA), Office of Superfund
Remediation and Technology Innovation (OSRTI) as part of the Sediment Assessment and Monitoring
Sheet (SAMS) series. The SAMS series of documents provide greater detail and discussion on topics
of interest in contaminated sediment management. This fact sheet presents a framework for
implementing adaptive site management within Superfund by performing early or interim actions
followed by a final action, guided by an adaptive site management plan. This fact sheet supplements
but does supersede or replace current guidance, and it does not impose legally binding requirements
on EPA, states, or the regulated community.
This document underwent an external peer review conducted by Environmental Management Support,
Inc., under contract to the EPA (Contract EP-W-13-016) according to the 4th Edition of the Science and
Technology Policy Council's Peer Review Handbook (EPA/100/B-15/001). Peer reviewers were
selected based on their expertise in site management and community engagement, representing a
diversity of backgrounds and affiliations. Formatting and production assistance was provided by ICF,
under contract to the EPA (Contract EP-W-14-001).
CONTACT INFO
For questions on this fact sheet please contact Karl Gustavson, OSRTI, at gustavson.karl@epa.gov or
Brigid Lowery, Director, Assessment and Remediation Division, OSRTI at lowerv.brigid@epa.gov.
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Adaptive Site Management - A Framework for Implementing Adaptive Management at Contaminated Sediment Superfund Sites
STATEMENT OF PURPOSE
This Sediment Assessment and Monitoring Sheet (SAMS), prepared by the U.S. Environmental
Protection agency (EPA), describes how adaptive site management can be applied to large, complex
contaminated sediment sites in a manner consistent with the Comprehensive Environmental Response,
Compensation, and Liability Act (CERCLA) and the National Oil and Hazardous Substances Pollution
Contingency Plan (NCP).
Adaptive site management is one option for planning remediation at large, complex Superfund
sediment sites with long remediation times and high levels of uncertainty regarding the remedial actions
necessary to achieve final, protective remediation goals. Adaptive site management relies on a plan
developed in consultation with stakeholders to describe how Superfund processes will be assembled
and utilized. The plan includes the adaptive site management elements of site-specific goals, actions,
monitoring, evaluation, and remedy adaptation and presents them within the Superfund context.
Planning early in the remedial process ensures that these elements are agreed upon and available to
guide decision making over the course of site cleanup.
INTRODUCTION TO ADAPTIVE SITE MANAGEMENT AT
SUPERFUND SEDIMENT SITES
Large and complex contaminated sediment sites often have long remediation timeframes; multiple,
widespread, and inter-connected sources of contamination; wide-ranging human and ecological
receptors; and uncertainty in the timing and magnitude of effect between sediment remediation and
reduction in risk to receptors. Sediment bed characterization is challenging because of heterogeneous
conditions and ongoing transport processes. Remediation is difficult to conduct in underwater
environments and may be prone to recontamination. At large, complex sediment sites, these issues
make it challenging to develop and select a final, protective remedy in a Record of Decision (ROD) prior
to conducting any remediation.
Adaptive site management combines iterations of remediation and monitoring to determine progress
towards remedial action objectives (RAOs) and remediation goals, inform uncertainties, and make
decisions about whether and when additional remediation is necessary to achieve RAOs. This
approach can facilitate progress at Superfund sites through:
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Adaptive Site Management - A Framework for Implementing Adaptive Management at Contaminated Sediment Superfund Sites
• agreement between stakeholders on what is known and what is unknown about the site;
• early management of high-risk areas and source areas; and
• a structured decision-making process that accommodates the uncertainty inherent to large,
complex cleanups while maintaining focus on achieving the site's final remediation goals.
Adaptive site management relies on monitoring to continually improve site understanding and track
progress towards goals. This allows decision makers to:
• better establish the contaminant relationship between soils/sediments, water, and biota;
• identify unknown contaminant sources or exposure drivers;
• assess the effectiveness of remedial approaches; and
• determine the degree of remediation necessary to achieve a final, protective remedy.
At a practical level, the value of adaptive site management at sediment sites is the potential for
expediting significant progress toward final remediation goals, while monitoring the system response
and gauging what, if any, additional steps are needed to achieve those goals. Remediation under
adaptive site management acts on what is known while acknowledging what is not fully understood. It
includes plans to collect the necessary information to reduce uncertainties and achieve a final,
protective remedy for the site. This approach allows work to proceed in areas with high contaminant
exposure and transport while additional data collection and testing of responses is conducted to
determine the appropriate level of remediation in remaining areas. (See Box 1 for additional
background and terminology.)
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Box 1. Background and Adaptive Management Terminology
Adaptive management at Superfund sites has been extensively discussed and reviewed for decades. EPA
recommends an iterative approach to decision making that will include "testing of hypotheses and
conclusions and foster re-evaluation of site assumptions as new information is gathered." (EPA 2002a,
Principle 6). The National Research Council (NRC) has published extensively on the use of adaptive
management in water resources and at contaminated sediment sites (NRC 2003, 2004, 2005, 2007).
Reviews have been published in academic and law journals (e.g., Apitz 2008, Cannon 2005). Federal
agencies and the Interstate Technology and Regulatory Council (ITRC) have produced adaptive site
management guidelines (Fischenich 2019, ITRC 2017, Williams et al. 2009). Adaptive management for
sediment sites is described in several EPA documents and its use is recommended at complex sites (EPA
2005, 2017a, 2017b).
So why is additional discussion needed? Adaptive management is not a single approach. In contaminated
sediment management, the term has been applied to decisions and processes from large to small where
outcomes may be uncertain. At sediment sites, examples have ranged from modifying sampling strategies
during characterization, to conducting pilot studies, to modifying approaches during remediation to improve
their performance. The applications have generally entailed collecting information during operations to
modify decisions, reflecting the "learning while doing" aspect of adaptive management. However, the over-
use of the term "adaptive management" at the small scale has diluted the meaning of adaptive management
as a long-term site management strategy. At large, complex Superfund sites, the fundamental uncertainty to
be adaptively managed is the degree of remediation that will be necessary to achieve a final, protective
remediation goal. The adaptive management process of remediation, monitoring, and evaluating progress
towards final remediation goals is well-suited to address this uncertainty.
In 2018, EPA addressed the wide range of purposes and definitions in adaptive management, describing
"site level" and "project level" adaptive management, with "site level" corresponding to broader strategies to
achieve site cleanup (EPA 2018a).1 This site level application of adaptive management to achieve site
remediation goals is consistent with the purposes of adaptive management in contaminated site cleanup
outlined in previous efforts (NRC 2003, 2005, 2007) and EPA's contaminated sediment guidance (EPA
2017a).
The term "adaptive site management" is used in this document, consistent with previous
applications (NRC 2003 and ITRC 2017), to establish that adaptive management is being used as a
long-term site management strategy, and to differentiate it from other uses of the term adaptive
management. Herein, adaptive site management is described as a formalized process to manage
risks from contaminated sediment sites where iterations of remediation, monitoring, and progress
evaluations are guided by a formalized adaptive management plan that establishes the goals of the
project, sets expectations, uses monitoring data to evaluate progress towards those expectations,
and adapts the remedy as necessary based on those evaluations.
1 Superfund Taskforce #3 (EPA 2018a) developed a broad working definition that encompassed the "site level" and "project
level" application of adaptive management: "Adaptive management is a formal and systematic site or project management
approach centered on rigorous site planning and a firm understanding of site conditions and uncertainties. This technique,
rooted in the sound use of science and technology, encourages continuous re-evaluation and management prioritization of site
activities to account for new information and changing site conditions. A structured and continuous planning, implementation
and assessment process allows EPA, states, other federal agencies, or responsible parties to target management and resource
decisions with the goal of incrementally reducing site uncertainties while supporting continued site progress."
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Adaptive Site Management - A Framework for Implementing Adaptive Management at Contaminated Sediment Superfund Sites
Adaptive site management may not be necessary or well-suited for all sites. For sites where final,
protective alternatives can be developed and evaluated using the standard Superfund process, and a
preferred alternative selected, there is likely no need for adaptive site management. At these sites,
contaminant(s) of concern (COC), sources, and exposure areas are defined, and a link between
remediation and RAO attainment is reasonably anticipated. If necessary, remedy refinement or
maintenance can occur through operations and maintenance protocols, remedy optimization,
incorporating flexibilities into RODs, contingency remedies, or formal remedy changes, such as an
Explanation of Significant Difference (ESD) or ROD amendment. Remedy effectiveness will be verified
and tracked through long-term monitoring as part of the five-year review. At other sites, it may be
appropriate to use removal or interim actions to quickly manage high risk areas or source areas without
accompanying adaptive site management, recognizing that remaining unacceptable risks will be
addressed by a final ROD.
ADAPTIVE SITE MANAGEMENT FRAMEWORK
Several adaptive site management frameworks have been developed over the years. These have
generally contained similar elements (e.g., NRC 2004, 2005, EPA 2017a, ITRC 2017):
1) Identification of a remediation goal,
2) Action(s) to make significant progress toward that goal,
3) Monitoring of progress toward the remediation goal, and
4) Use of monitoring information to guide decisions regarding additional actions to achieve
the remediation goal.
These elements are typically preceded and supported throughout adaptive site management by
development and refinement of the conceptual site model (CSM) and stakeholder engagement.
The adaptive site management framework presented in this document is based on these elements and
is intended to be applied as part of existing Superfund guidance.
"[w]hen applying [adaptive management] at CERCLA sites, activities and response decisions
must be done in accordance with CERCLA regulations, policy, and guidance. Moreover, the
application of [adaptive management], to the extent practicable, strives to establish site or
project strategies that employ existing CERCLA process flexibilities such as the use or
application of early and/or interim actions to address immediate risks, to mitigate source
migration, and/or to return portions of sites to beneficial use pending more detailed evaluations
at other parts of sites" (EPA 2020).
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Adaptive Site Management - A Framework for Implementing Adaptive Management at Contaminated Sediment Superfund Sites
One way to implement adaptive site management within the Superfund context is to execute early
actions followed by a final action2, guided by an adaptive site management plan focused on evaluating
progress toward and attainment of remediation goals (see Box 2). That example process is described
below.
Box 2. Terms: Actions and Goals
Early and final actions. In this document, the term early action refers to actions taken early in the process,
prior to the final action and may include removals or interim actions (see section 8.2.2 in EPA,1999). The
final action is the final remedy selected in the final ROD that is intended to be protective of human health
and the environment.
Remediation goals. The remediation goal is the contaminant concentration in the media (e.g., sediments
and/or fish) that is the goal of the early or final action. Final remediation goals are, as indicated in the NCP,
intended to be protective of human health and the environment (see footnote 3). Early action remediation
goals are associated with the early actions and reflect the limited scope of the action (for example, "[t]he
interim action should protect human health and the environment from the exposure pathway or threat it is
addressing, and the waste material being managed at least in the short term (until a final ROD is
implemented))" (EPA 1999, highlight 8-7).
The specific usage of terms associated with "remediation goals" varies during the Superfund process as
information is collected and needs change. For example, "PRGs [preliminary remediation goals] are refined
into final remediation goals throughout the process leading up to remedy selection... The ROD itself,
however, should include a statement of final clean-up levels based on these goals..." (EPA 1991, section
1.5). Regions should use the terms appropriate for the site, remedial action, and timing, consistent with
guidance.
DEVELOPING AN ADAPTIVE SITE MANAGEMENT PLAN
The adaptive site management plan is a site strategy document that guides the iterative remedial
actions that will ultimately result in a final, protective remedy. The plan is developed and implemented
with the stakeholder group (e.g., potentially responsible parties, States, trustees, Tribal nations, and
affected communities) and should include meaningful community involvement "early and often" (EPA
2002a, Recommendation 2). The adaptive site management plan does not replace the need for a
decision document (a ROD or, in the case of a removal action, an action memorandum) for any
response action under CERCLA.
The plan describes the relationship among operable units (especially those that constitute source
control for the sediment action) and the site's use of early and final actions to achieve final RAOs and
2 EPA 2017b: "Under an Adaptive Management strategy, Regions are encouraged to consider greater use of early
and/or interim actions including use of removal authority or interim remedies, to address immediate risks, prevent
source migration, and to return portions of sites to use pending more detailed evaluations on other parts of sites."
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Adaptive Site Management - A Framework for Implementing Adaptive Management at Contaminated Sediment Superfund Sites
remediation goals. The plan relies on the CSM and includes the goals, expectations, and timeframes
for the actions, as well as the timepoints when monitoring data will be evaluated and decisions will be
made regarding the need for additional remediation. The adaptive site management plan should be
reviewed periodically and updated based on new site information, if warranted.
An adaptive site management plan using this process includes the following steps.
1. Establish the remediation goal(s). The site's RAOs "...provide a general description of what the
cleanup will accomplish..." (EPA 1999) while the remediation goals are the contaminant exposure
levels associated with the RAO.3 As such, the remediation goal is the quantitative indicator that the
RAO has been achieved. The adaptive site management plan relies on the remediation goal as the
benchmark for quantitatively understanding progress and establishing when the remediation has been
completed. Optimally, the remediation goal will be the protective remediation goal associated with a
final remedy and attainment of acceptable risk at the site, consistent with the NCP.4 This final goal
represents the desired condition of the system post-remediation and allows for an understanding of the
degree to which early actions make progress toward that final goal.
This final remediation goal will be site-specific, derived consistent with the NCP and EPA guidance, and
will consider applicable or relevant and appropriate requirements (ARARs), acceptable risk (10"4 to 10"6
excess upper bound lifetime cancer risk and/or a non-cancer hazard quotient of 1 or below), technical
limitations (including background)5, uncertainty, and other pertinent information (NCP: 40 CFR
300.430(e)(2)(i)). The final RAOs and remediation goals are distinct from remediation goals associated
with the early action(s). Early actions have separate remediation goals specific to those actions that are
intended to make significant progress toward final remediation goals. For example, the RAO of an early
action may be to significantly reduce sediment COC exposure concentrations and may specify a
threshold sediment concentration as the early action remediation goal. The final remedy will establish a
final remediation goal that represents acceptable exposure levels protective of human health and the
environment (for the COCs, media [e.g., sediments and/or fish] and exposure pathways defined in the
3 40 CFR 300.430(e)(2)(i) of the NCP states that site managers, "Establish remedial action objectives specifying
contaminants and media of concern, potential exposure pathways, and remediation goals... Remediation goals
shall establish acceptable exposure levels that are protective of human health and the environment and shall be
developed..."
4 Ibid
5 "The contribution of background concentrations to risk associated with CERCLA releases may be important for
refining specific cleanup levels for COCs that warrant remedial action. For example, in cases where a risk-based
cleanup goal for a COC is below background concentrations, the cleanup level may be established based on
background' (EPA 2002b).
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final RAOs). Final and early action remediation goals should be measurable and specific in terms of
COCs, media, areas over which they will be measured, and how data will be analyzed to ascertain goal
attainment (see EPA 2017a, Recommendation 5 and additional discussion below).
Early in the process, it is possible that the risk assessment is not yet finalized, or information is not
sufficient to establish a final remediation goal. In such cases, a preliminary remediation goal (PRG)6
can be used, and an early action that makes substantive progress toward that goal (or that significantly
decreases current COC exposures) could be implemented. A final remediation goal is normally not
required for an early or interim action; however, in adaptive site management, having the final action
remediation goal as early as possible is important to understand and communicate the degree to which
the early action is consistent with and makes progress towards the final remediation goal. The adaptive
site management plan is intended to be revisited and updated, allowing information on the final
remediation goal to be included when it is available. It is also recognized that, consistent with five-year
review procedures (EPA 2001), exposure assumptions, cleanup levels7, and RAOs will be periodically
re-evaluated to determine if they are still valid (and the outcomes included in updates to the adaptive
site management plan).
2. Determine the action. At this step, the site's CSM should provide a "representation of the
environmental system and the physical, chemical, and biological processes that determine the transport
of contaminants from sources to receptors" (EPA 2005). Site data should be able to depict current
areas of COC exposure and transport to allow the identification and remediation of the primary COC
contributors. An early action would be designed to achieve early action RAOs and remediation goals
and make significant progress toward final remediation goals. The actions would target areas of highest
6 "Initially, preliminary remediation goals are developed based on readily available information, such as chemical-
specific ARARs or other reliable information. Preliminary remediation goals should be modified, as necessary, as
more information becomes available during the RI/FS" (NCP, 40 CFR 300.430(e)(2)(i)).
7 When the ROD is issued, cleanup levels and final remediation goals are synonymous: "In the ROD, it is
preferable to use the term "remediation level" or "cleanup level" rather than "remediation goal" in order to make
clear that the Selected Remedy establishes binding requirements." (EPA 1999).
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risk, exposure, and COC transport to biota,
downstream, or adjacent areas (see Box 3).
Remediation in targeted areas may be
anticipated to expedite recovery of remaining,
lesser contaminated areas. Some sites and
watersheds may be so large and contamination
so widespread that multiple early actions may be
necessary. In those cases, early actions make
significant progress by targeting the most
significant sitewide sources of COC exposure
and transport but may only achieve early action
goals on a localized scale. When combined,
those localized actions make significant progress
toward sitewide final RAOs and remediation
goals.
3. State the expectations. In this adaptive site
management framework, early actions are
intended to achieve the early action's
remediation goals while making significant
progress towards the site's final, protective remediation goals. The adaptive site management plan
should state the goals of the early action(s) and the expectations and timeframes for attainment of final
remediation goals following the early action. The stated goals and timeframes provide the basis for
evaluating remedy performance (Step 5, below).
The 2017 Contaminated Sediments Directive (EPA 2017a) advised that an adaptive management plan:
"a. Specifies key indicators (i.e., monitored parameters that are tied to the remedial action
objectives),
b. Selects specific trigger criteria (i.e., concentrations and timeframes) of those key indicators
that might trigger a change in the remedy, and
c. Specifies the specific actions based on attainment or non-attainment of trigger criteria."
Box 3. What constitutes a significant
area/action?
Early actions that target a greater portion of COC
exposure and transport make greater progress to
final, protective remediation goals. The most
relevant examples of adaptive site management
principles applied at sediment sites, such as the
Diamond Alkali, Passaic River, Operable Unit 4
(EPA 2021) and Ventron/Velsicol, Berry's Creek,
Operable Unit 2 (EPA 2018b), sought 93-95%
decreases in exposure to the primary COCs,
respectively, and targeted the most upstream and
highly contaminated areas. Actions that reduce
contaminant exposures and transport create
immediate risk reduction but can also foster
conditions where natural recovery is able to address
lesser contaminated areas (assuming natural
recovery processes exist). Actions at that
magnitude may obviate the need for subsequent
actions or monitoring after the early action may help
identify remaining areas driving unacceptable risk.
The Bunker Hill Superfund Site in Idaho and
Washington is another site using adaptive site
management principles. This site covers a vast
area, much larger than the preceding examples,
and the first iterations of actions targeted high-
priority areas based on their potential to serve as a
source, exposure, or recontamination in the most
upstream and heavily contaminated segments of
the site (EPA 2012).
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These elements encompass several aspects of
planning, monitoring, evaluation, and adaptation.
They are critical to communicate expectations,
including how the remediation will be monitored
and evaluated, and how decisions will be made
based on those evaluations. The concentration
and timeframe "trigger criteria" are particularly
important as they reflect expected progress
toward the final remediation goal.8 For example,
the concentration and timeframe that might
trigger a change in the remedy are whether the
final remediation goal (in the stated media and
area) was achieved 15 years following the early
action.9 Because of the importance of the trigger
criteria, they should be unambiguous and specific
in terms of COCs, media, area, and associated
level of contaminant exposure. The plan also
needs to be clear on when data will be evaluated
and decisions will be made (See Box 4).
The confidence in future predictions and the
ability to establish triggers and decision timepoints will vary depending on the site (see discussion in
Box 5). For example, at large, watershed-wide mining sites, the timeframe to attain final remediation
goals may be highly uncertain as multiple iterations of priority area remediation are planned and the
identification of additional source areas may be anticipated. The adaptive site management plan should
state this expectation and that routine monitoring and data evaluations will be used to identify priority
areas and chart progress toward final remediation goals and RAOs. As information is gathered,
timeframes will be revised and decision timepoints established as the adaptive site management plan is
Box 4: Timepoints for Data Review and
Decisions
The adaptive site management plan should be clear
on the timing for data evaluation and management
decisions. These are critical timepoints for
stakeholder involvement. Establishing the
evaluation and decision timepoints provides
certainty that performance will be evaluated and
that additional actions will be conducted, if
necessary, based on progress towards objectives.
In the simple example where a trigger criterion is
set at 15 years from the early action, the adaptive
site management plan would include data
evaluation timepoints every five years (consistent
with five-year review requirements) and a decision
timepoint at year 15. The evaluation and decision
timepoints also provide the opportunity to update
the CSM and adaptive site management plan.
Terms:
Evaluation timepoints: Timepoints when collected
data will be evaluated and compared to
expectations. While data may be collected and
compiled more frequently, these evaluation
timepoints are an opportunity for stakeholders to
evaluate whether the stated expectations are being
met.
Decision timepoints: Timepoints when collected
data are compared to the trigger criteria to inform a
management decision.
8 Again, the final remediation goal is distinct from the early action remediation goal.
9 In this example, the trigger criterion is the same as the final remediation goal. This may not always be the case;
in some cases, a trigger criterion may represent progress toward, but not attainment of, the final remediation goal.
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updated. At other sites, expectations for the
degree and timing of remediation are more
certain. For example, an early action may be
intended to make significant progress by
remediating high concentration areas and
attaining final remediation goals over time by
the iterative remediation or natural recovery of
lower concentration areas. At set decision
timepoints, the stated expectations and trigger
criteria will be evaluated.
An important aspect to be addressed by
stakeholders is the potential need to revise the
decision timepoints, trigger criteria, and
remediation goals based on new information.
These adaptive site management elements are
directly used to determine whether to conduct
additional remediation, so their revision will be
significant. Evaluating new information and
adapting to this information is central to
adaptive site management. However, since
remediation goals and acceptable risk reduction
timeframes are primarily a risk management
function subject to Superfund's requirements for
protective and cost-effective remedies, they are less likely to be modified by factors such as site
uncertainties, unexpected rates of concentration declines, or model discrepancies. However, as
described in Step 1, new information can be relevant to their basis.
4. Monitor progress. A strong monitoring program is critical in adaptive site management. Baseline
sampling is needed to support a CSM, adequately depict current conditions, and allow site managers
"to evaluate, predict, and communicate environmental improvements from implemented remedial
actions" (see EPA 2017a, Recommendation 9). Monitoring during and after remediation provides the
basis for understanding conditions and comparing them to the stated expectations. It is also key to
understanding why those expectations were or were not achieved. The results are used to refine the
CSM, reduce uncertainty, and inform next steps.
Box 5. Predictions, Modeling, and Monitoring in
Adaptive Site Management
Adaptive site management relies on the site's CSM
to make predictions about effects from remediation.
The CSM will include a baseline data set that is
sufficiently robust to support predictions and permit
an understanding of the magnitude of change
during future monitoring events. A wide variety of
approaches are used at sites to depict those future
conditions. Sites have used empirical approaches
such as applying observed rates of COC reduction
to predicted post-remediation concentrations,
simple modeling approaches such as sediment
deposition and mixing models based on measured
deposition rates, and the more complex and time-
consuming linked hydrodynamic, sediment
transport, and contaminant transport model
complexes.
In the adaptive site management paradigm, it is
recognized that future predictions are fundamentally
uncertain, and that monitoring will be used to refine
predictions, inform progress, and support future
decisions (see also Principle 6 in EPA 2002a and
Recommendation 7 in EPA 2017a). One advantage
is that this approach lessens the need for the
unattainable goal of model "accuracy" in large,
complex, and uncertain environments and making
final decisions based on incomplete understanding
of the site. Instead, adaptive site management
prioritizes monitoring to define trends, update
predictions, verify success, or identify unforeseen
problems and the areas or processes driving those
problems. Intrinsic to the monitoring and learning
process are regular reviews of the CSM and the
opportunity to update it based on new information.
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Monitoring key indicators of RAOs and remediation goals is central to evaluating remedy performance.
EPA highlights the need for specificity in these stated expectations (EPA 2017a):
"A remedy's risk reduction expectations should answer several fundamental questions:
¦ What condition (e.g., contaminant concentration or level of toxicity) is expected to be achieved?
¦ In what media (e.g., sediment, fish tissue, surface water, porewater)?
¦ In what area?"
These stated expectations communicate anticipated performance in terms of COCs, media, receptors,
and the associated area. The adaptive site management plan should include a description of the
monitoring program that is designed to evaluate stated expectations and remedy performance.
Considering the nature of sites that are good candidates for adaptive site management, the program
will likely include multiple iterations of data collection prior to reaching the decision timepoint when
trigger criteria are evaluated. This repeat sampling would permit a greater understanding of the rate,
variability, and distribution of site responses and may provide information to modify the CSM or
monitoring program.
Monitoring program design is beyond the scope of this document, but EPA recommends "[t]he
monitoring endpoints used to measure progress towards or achievement of RAOs...are site-specific,
and should directly indicate the RAO and be linked to the remediation..." (EPA 2017a). Clarity and
specificity in the expectations and how criteria will be evaluated are essential to providing an
unambiguous basis for reviewing and modifying the remedy. The trigger criteria should be specific to
the media; establish whether remediation goal comparisons are to individual samples, composites, or
areal averages; specify the area over which samples will be aggregated; and describe how data will be
analyzed and compared to the goals.10 Spatial and temporal density of sampling should be sufficient to
reliably indicate progress towards or attainment of goals over the relevant exposure area and to identify
problematic areas. Methods for developing monitoring programs to assess cleanup level attainment are
discussed in EPA guidance (EPA 1989, 2004).
10 For example, a monitoring plan could establish that yellow perch and largemouth bass will be sampled every
two years after the completion of the early action. Sampling design will include chemical and lipid analysis of
whole-body individual (largemouth) and composites (yellow perch) with adequate replication such that the
average fish tissue concentration in each 1-mile section is expected to have a relative standard deviation no
greater than 50%. The expectation (and in this case the trigger criteria) is to achieve an average fish tissue
concentration of 0.5 ppm in each 1-mile section of river from river mile 0 to 5 within 10 years of the early action.
The 95% upper confidence limit of each 1 -mile average for each species will be compared to the trigger criteria at
the decision timepoint (year 10).
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Monitoring also helps diagnose why goals were or were not achieved by providing results with sufficient
spatial and temporal resolution to indicate the areas or sources slowing or driving the non-attainment of
remediation goals. However, such monitoring may not provide adequate context to understand why a
remedy did or did not perform as anticipated. This "diagnostic" monitoring helps to diagnose the drivers
of the observations and is particularly important where site uncertainties drive the need for adaptive site
management approaches. As such, a monitoring plan should also include monitoring of processes to
inform CSM uncertainties and help identify why trigger criteria have not been achieved. For example,
supporting information such as sediment bed stability analyses (e.g., through repeated bathymetric
surveys) and upland or lateral loading data can help ascertain drivers of anomalous results (e.g.,
whether high COC concentrations are related to un-remediated site sediments or off-site COC
sources). Such information can be used to support decisions in the next stage. To provide a direct,
contemporaneous link to the primary indicators, this diagnostic monitoring can occur during routine
synoptic sampling of the primary indicators. Separate efforts may also be needed to address specific
needs (e.g., high-resolution sampling in specific areas to determine processes responsible for patterns
seen in fish, water, or sediment COC concentrations).
5. Evaluate and adapt. The trigger criteria for adapting the remedy should be evaluated at the decision
timepoints stated in the adaptive site management plan by comparing data from the monitoring
program to the stated expectations. At the decision timepoint, the anticipated progress toward or
attainment of the final remediation goals is assessed. If the anticipated progress is not achieved, a
range of outcomes are possible based on the process described in the site's adaptive site management
plan. For example, outcomes could include performing additional sampling and analyses to evaluate
the drivers of unanticipated results, conducting additional remediation to address unacceptable
exposures, or continuing the monitoring program and delaying the decision until the next evaluation
timepoint. These actions will be site-specific and should be clearly described in the adaptive site
management plan along with determining factors for the selection. The iterative nature of the process
also recognizes that the CSM and the adaptive site management plan (including remediation goals or
timeframes) may be updated, if necessary, as warranted by new information or site data.
Decisions at this point may indicate success, additional remediation, or that revisions to expectations or
monitoring programs are needed. In some cases, decision points may be explicitly intended to establish
the next iteration of priority areas for remediation. Actions resulting from the data review at the decision
timepoint may require additional Superfund decision documents (e.g., ESD, ROD amendment, interim
ROD, final ROD, etc.) depending on the type and magnitude of changes and the proposed action,
consistent with existing policies (EPA 1999, 2001).
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Adaptive Site Management - A Framework for Implementing Adaptive Management at Contaminated Sediment Superfund Sites
IMPLEMENTING AN ADAPTIVE SITE MANAGEMENT PLAN
The NCP and EPA's Superfund guidance already have processes that correspond with the framework
for implementing adaptive site management (see Figure 1). For example, the NCP preamble describes
that the program has a bias for action, and that actions should be taken despite uncertainty.11 RAOs
and remediation goals are required by the NCP12, and when contaminants are left in place, the action's
objectives, remediation goals, and remedy should be evaluated every five years and revised if they are
no longer valid to ensure continued protectiveness of human health and the environment (EPA 2001).
There are many options to implement early actions in Superfund that can be used to make significant
progress toward final protective remediation goals, including removal actions, interim actions, or
contingent actions.13 Long-term monitoring to assess progress toward and attainment of remediation
goals, as well as the drivers of those results, is strongly emphasized in EPA guidance related to
contaminated sediment management (EPA 2002a, 2005, 2017a). There are several options for
modifying remedial decisions, depending on the degree of change compared to existing decisions (EPA
1999). At PRP-lead sites, the intent to use adaptive site management as a long-term site strategy
should be recognized in the enforcement agreement and statement of work.
Overall, it is anticipated that existing procedures and regulations can be used in conjunction with an
adaptive site management framework at large, complex contaminated sediment sites to achieve a final,
protective remedy. Regions should consider whether these adaptive site management approaches are
appropriate for use at their sites to address immediate risks, prevent source migration, and to inform,
select, and achieve a final remedy.
11 "In deciding whether to initiate early actions, EPA must balance the desire to definitively characterize site risks
and analyze alternative remedial approaches for addressing those threats in great detail with the desire to
implement protective measures quickly. Consistent with today's management principles, EPA intends to perform
this balancing with a bias for initiating response actions necessary or appropriate to eliminate, reduce, or control
hazards posed by a site as early as possible." (55 Fed. Reg. at page 8704, March 8, 1990).
12 40 CFR 300.430(e)(2)(i) of the NCP states that site managers, "Establish remedial action objectives specifying
contaminants and media of concern, potential exposure pathways, and remediation goals... Remediation goals
shall establish acceptable exposure levels that are protective of human health and the environment and shall be
developed..
13 EPA 1997: "A "phased approach" to site investigation and cleanup generally will accelerate risk reduction and
provide additional technical site information on which to base long-term risk management decisions. Phased
cleanup approaches should be employed wherever practicable (40 CFR 300.430(a)(1)(H)(A)). For more
information about the use of early actions to expedite site cleanup, see SACM Guidance and the Ground-Water
Presumptive Strategy."
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Adaptive Site Management - A Framework for Implementing Adaptive Management at Contaminated Sediment Superfund Sites
Figure 1. Framework for Adaptive Site Management Plan
Adaptive Site Management Elements
Documentation
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• Final action: COCs, media, final remediation
goals, areas, and timeframes
• Adaptive site management plan: key
indicators, monitoring frequency, decision
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Monitor Progress
> Monitor key indicators of RAOs and
remediation goals
• Monitor diagnostic indicators
Evaluate and Adapt
• Evaluate monitoring data at evaluation and
decision timepoints
• Re-evaluate adaptive site management plan
• Adapt as necessary
•Remedial investigation, feasibility
study, focused feasibility study
•Non-time critical removal action
(NTCRA) memorandum, interim ROD
•NTCRA memorandum, feasibility study,
interim ROD, Final ROD, or equivalent
•Adaptive site management plan
•NTCRA memorandum, feasibility study,
interim ROD, Final ROD, or equivalent
•Adaptive site management plan
•Performance monitoring plans
•Long-term monitoring plan
•Five-year review
•ESDor ROD Amendment
•Final ROD (or equivalent), new NTCRA
memorandum, or interim ROD
•Adaptive site management plan
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Adaptive Site Management - A Framework for Implementing Adaptive Management at Contaminated Sediment Superfund Sites
REFERENCES
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EPA. 1989. Methods for Evaluating the Attainment of Cleanup Standards Volume 1: Soils and Solid
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EPA. 1991. Risk Assessment Guidance for Superfund: Volume I - Human Health Evaluation Manual
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Adaptive Site Management - A Framework for Implementing Adaptive Management at Contaminated Sediment Superfund Sites
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Interior, Washington, DC.
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