Q\ Reusing Cleaned Up
J Superfund Sites:
Ecological Use Where
Waste is Left on Site
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On the Cover
Top left
Wetlands created at the Bowers Landfill Superfund site in Pickaway, Ohio provide habitat
for plants and wildlife.
Top Right
Post-treatment hillsides environment in the Hillsides area of the Bunker Hill Superfund site
in Kellogg, Idaho. A mixture of biosolids and ash was successful in helping revegetate the
area to reduce sedimentation and provide a healthy wildlife habitat for elk and other native
species.
Bottom left
A meadow provides habitat for plants, birds, and mammals at the Army Creek Landfill
Superfund site in Newcastle County, Delaware.
Bottom right
Aerial view of the Northwest 58th Street Landfill Superfund site along the eastern edge of the
Everglades wetlands in Dade County, Florida.
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Office of Solid Waste
and Emergency Response
(5104G)
OSWER 9202.1-27-D
July 2006
vwwv.epa.gov/superfund
Reusing Cleaned Up
Superfund Sites:
Ecological Use Where
Waste is Left on Site
Office of Superfund Remediation and Technology Innovation
Office of Solid Waste and Emergency Response
U.S. Environmental Protection Agency
Washington, D.C. 20460
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Notice
This document is intended for information purposes and does not create new nor alter existing
Agency policy or guidance. The document does not impose any requirements or obligations on EPA,
states, other federal agencies, or the regulated community. The sources of authority and requirements
described in this document are the relevant statutes and regulations (e.g., the Comprehensive
Environmental Response, Compensation, and Liability Act, or CERCLA). EPA welcomes public
comments on this document at any time and may consider such comments in future revisions of this
document. EPA and state personnel may use and accept technically sound approaches different from
those described in this document, either on their own initiative or at the suggestion of potentially
responsible parties or other interested persons. Therefore, interested parties are free to raise questions
and objections about the information in this document and the appropriateness of the application of
the information in this document to a particular situation. This document is not intended, nor can it be
relied upon, to create any rights, substantive or procedural, enforceable by any party in litigation with
the United States.
For More Information
For more information on the Superfund Redevelopment Program, including information about
current developments, pilot programs, tools and resources, and case studies, visit the Program's web
site at http: //www.epa.gov/superfund/progranis/recvcle/index.htm or contact the following
numbers:
Outside the Washington, D.C. area: 800-424-9346;
TDD for the hearing impaired outside the Washington, D.C. area: 800-533-7672
In the Washington, D.C. local area: 703-412-9810; or
TDD for the hearing impaired in the Washington, D.C. local area: 800-412-3323.
Hours: 9:00 AM to 5:00 PM Eastern Standard Time, Monday through Friday.
Closed on federal holidays.
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Reusing Superfund Sites: Ecological Use Where Waste is Left On Site
Preface
As of December 2005, about 460 cleaned up Superfund sites have been returned to beneficial
use. At least 56 are being used primarily for ecological purposes, such as wildlife habitats. Many
of the other approximately 404 sites, which were redeveloped for commercial, industrial, or
other uses, also contain significant ecological areas. A large number of other Superfund sites,
including certain non-time-critical removal sites, and contaminated sites in other cleanup
programs, have potential for similar uses after they are cleaned up. The U. S. Environmental
Protection Agency (EPA), through the Superfund Redevelopment Program, encourages the
beneficial reuse of Superfund sites, while working towards EPA's overriding objective for all
sitesto ensure protection of human health and the environment. With forethought and effective
planning, communities and Natural Resource Trustees (Trustees) can return sites to beneficial
use without jeopardizing the effectiveness of the remedy put into place to protect human health
and the environment. Ecosystems are essential to all aspects of human existence and their value
in urban, suburban, and rural areas is often not fully recognized when decisions are made about
land use.
This report provides technical information useful in planning, designing, and implementing
remediation and reuse projects at sites that are to include ecological reuse. It is especially useful
for sites where the remedy calls for on-site containment or treatment of contaminants and
contaminated materials or post-construction monitoring or treatment. This information may be
useful to remediation planners and managers when considering how the remedy and reuse
options may affect each other during various stages of EPA's processes for managing NPL sites
and non-time-critical removal actions. The document may also be useful to communities,
potentially responsible parties (PRPs), Trustees, and other stakeholders planning for the reuse of
Superfund sites in coordinating with the cleanup team during all stages of the cleanup process.
Close coordination with reuse and remediation personnel will help in identifying acceptable
reuse scenarios that will not hinder the protectiveness of the remedy, sharing information about
local ecosystems and contamination, and identifying, selecting, and implementing remediation
approaches that will allow the anticipated reuse. The report draws from experiences at completed
and current reuse projects, EPA technical guidance, and other sources to describe ecosystem
characteristics and remediation approaches that have been used to accommodate ecological uses
at Superfund sites where contaminated material has been left on site.
This document is intended for information purposes only, and does not create new or alter
existing Agency policy or guidance. It is one of a series of planning reports being developed
under EPA's Superfund Redevelopment Program to inform interested parties at hazardous waste
sites about planning and technical issues that may arise during the remediation process (during
which it selects, designs, and implements remedies) when reuse of a site is intended following
cleanup. Other reports in this series provide technical information on the reuse of Superfund sites
with on-site containment or treatment for commercial facilities, golf courses, and other outdoor
recreational areas.
Preface
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Reusing Superfund Sites: Ecological Use Where Waste is Left On Site
While the information in this report may be useful in many circumstances that may occur at a
wide range of sites, it may not cover all considerations that might apply at federal facilities sites.
Hence, managers at those sites are encouraged to coordinate restoration and reuse projects with
EPA's Federal Facilities Restoration and Reuse Office. Managers at federal facilities engage in
practices similar to those described in this report. In addition, at some federal facility sites, there
may be greater opportunities for ecological uses due to certain site attributes and circumstances,
such as large land areas and remote locations. In addition, federal statutes promote conservation
areas through the creation of national wildlife refuges at former Superfund sites and through
conservation authorities granted to the Department of Defense. These authorities are designed to
mitigate encroachment from the military and local community by creating ecological use buffers
next to active defense installations.
Preface
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Reusing Superfund Sites: Ecological Use Where Waste is Left On Site
Table of Contents
Page
Notice ii
Preface iii
Table of Contents v
Section 1. Introduction 1
1.1 Purpose 2
1.2 Who Should Read the Report and Why 2
1.3 Superfund Redevelopment Program 3
1.4 Integrating Reuse Plans With Cleanup Remedies 4
1.4.1 Consideration of Future Land Uses 4
1.4.2 Timing 5
1.4.3 Enhancements 6
1.5 Ecological Reuse of Hazardous Waste Sites 7
1.6 Organization of Report 8
Section 2. Planning for Ecological Reuse of Superfund Sites 9
2.1 Major Natural Resource Management Issues 9
2.1.1 Biodiversity 10
2.1.2 Contaminant Bioaccumulation 10
2.1.3 Threatened and Endangered Species 11
2.1.4 Potential for Unintended Consequences 11
2.1.5 Scope of Ecological Reuse of Superfund Sites 12
2.2 Coordinating Ecological Reuse With the Superfund Process 12
2.2.1 Establishing Remediation Goals 13
2.2.2 Ecological Risk Assessment and Natural Resource Damages 14
2.2.3 Typical Ecological Reuse Development Process 14
2.2.4 Superfund Site Management Process 16
2.3 Natural Resource Trustees and Other Organizations 17
2.3.1 Natural Resource Trustees 17
2.3.2 Biological Technical Assistance Groups and Other Agencies 18
2.4 Site Characteristics That Affect Ecological Reuse 19
2.5 Site Configurations 20
2.5.1 Closed-in-Place Sites 21
2.5.2 New Containment Systems 21
Section 3. Remediation Considerations for Ecological Reuse 23
3.1 Containment System Covers 23
3.2 Other Containment System Components 25
3.3 Associated Remedial Technologies 25
3.4 Remedy Planning and Design Issues 29
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Reusing Superfund Sites: Ecological Use Where Waste is Left On Site
Page
3.5 Minimizing Ecological Damage During Remedy Construction 32
3.6 Operation and Maintenance 35
3.6.1 Planning and Designing for Stewardship 35
3.6.2 O&M of Remedy Components 36
3.6.3 Monitoring Ecological Risks 37
3.6.4 Institutional Controls 37
Section 4. Wetlands and Superfund Remediation 39
4.1 Wetland Regulatory Requirements 40
4.2 Wetland Characteristics 41
4.3 Wetland Vegetation and Hydrology 42
4.4 Wetland Wildlife 43
4.5 Remedy Design and Construction Involving Wetlands 45
4.6 Wetland Maintenance 46
4.7 Sources for Technical Assistance for Wetlands 47
Section 5. Stream Restoration and Superfund Remediation 49
5.1 Evaluating Stream Corridor Conditions 49
5.2 Stream Corridor Restoration Considerations 50
5.3 Construction Techniques 52
5.4 Designing for Long-Term Habitat 52
5.5 Sources of Technical Assistance 53
Section 6. Terrestrial Ecosystems and Superfund Remediation 55
6.1 General Revegetation Principles 55
6.2 Meadows 57
6.3 Semi-Arid and Arid Lands 58
6.4 Maintenance of Vegetated Areas 59
6.5 Sources of Technical Assistance 60
References 61
Appendix A. Ecological Reuse Case Studies A-l
A. 1 Silver Bow Creek/Warm Spring Ponds, Butte, Montana A-2
A.2 Bowers Landfill, Pickaway County, Ohio A-5
A.3 Cherokee County Galena Subsite, Cherokee County, Kansas A-7
A.4 Army Creek Landfill, New Castle County, Delaware A-8
A.5 Bunker Hill Mining and Metallurgical Site, Kellogg, Idaho A-10
Appendix B. Acronyms B-l
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Reusing Superfund Sites: Ecological Use Where Waste is Left On Site
Section 1. Introduction
Former landfills, abandoned dumps, mining areas, and other contaminated sites throughout the
United States, once thought to be of limited or no value, are being transformed into viable
habitats where plants and animals can flourish. More than 56 of the approximately 460
Superfund sites that have been redeveloped over the past 25 years are being used primarily for
ecological purposes. Cleaned up Superfund sites are being used for wetlands, meadows, streams,
and ponds, where they provide habitat for terrestrial and aquatic plants and animals, and for low-
impact or passive recreation, such as hiking and bird watching. In addition, many sites that were
redeveloped primarily for other purposes, such as commercial or recreational facilities, also
contain significant ecological components or green space.
Healthy ecosystems are important to all aspects of our lives, and it would be difficult or
impossible to sustain our society without them. Ecosystems provide benefits to society both
directly and indirectly. Healthy ecosystems provide products such as food, fuel, fiber, and water;
regulating services, such as flood control, surface water runoff regulation, habitat maintenance
and restoration, and carbon sequestration; and nonmaterial assets such as recreational
opportunities, aesthetics, and cultural amenities.
At many successfully redeveloped sites, contaminated material has been left on the property in
containment systems designed to protect people and the environment from exposure and prevent
contaminant migration. A number of redeveloped sites are also being cleaned up with in-situ
treatment technologies that use biological (including phytoremediation), thermal, and
physical/chemical processes to treat contaminated material in place. These remediation
approaches are used because it is impractical or unnecessary to completely remove all the
contaminated material or because excavation or removal actions would do more harm than
leaving the material in place. These remedies are practical approaches to reducing exposure and
bioavailability of the contaminants, thereby protecting people and the environment from the
potential risks and allowing beneficial reuse of a site. To prevent long-term risks to human health
and the environment, redevelopment planners integrate into their plans any aspects of a remedy
that are designed to monitor and maintain its effectiveness.
This report discusses approaches for ensuring that these containment and treatment systems can
accommodate the selected ecological uses while ensuring that reuse activities do not reduce the
effectiveness of the remedy. The successful reuse of a remediated site for ecological purposes
typically involves careful planning, involvement of Natural Resource Trustees (Trustees),
communities, and other parties, and appropriate design, construction, and post-construction
operation and maintenance practices. The report is based on the combined experiences of
successful Superfund remediation and reuse projects, EPA technical guidance, and other sources.
Section 1. Introduction
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Reusing Superfund Sites: Ecological Use Where Waste is Left On Site
1.1 Purpose
This report was developed for site managers, communities, property owners, developers, natural
resource trustees, and others who might have an interest in Superfund sites at which ecological
resources are to be created, restored, improved, or protected. It provides information useful for
planning, designing and implementing site cleanups that will support valuable ecosystems while
remaining protective of human health and the environment. The information could also be
applied at certain non-time-critical removal sites and waste sites addressed under and other
cleanup programs. The report describes how redevelopment and remediation efforts can be
coordinated to ensure successful ecological projects at sites where some or all of the
contaminated materials are to be left or treated on site. It focuses primarily on planning-level
issues, not detailed design information. The document does not mandate how communities,
property owners, and Trustees plan for the reuse of cleaned up sites. It is generally their
responsibility to decide how these properties will be used, so long as the reuse activities do not
reduce the protectiveness of the remedy. Cooperation and coordination between the interested
groups and regulatory agencies can help ensure practicable solutions.
This report in no way alters established EPA policies on remedy selection for Superfund sites.
The national program goal of the Superfund remedy selection process is to "select remedies that
are protective of human health and the environment, that maintain protection over time, and that
minimize untreated waste" (40 CFR 300.430(a)(l)(i)). In many instances, Superfund remedies
include combinations of treatment for "principal threat wastes" (highly concentrated or mobile
contaminated material), engineering controls to contain lower-concentration contaminants, and
institutional controls (i.e., restrictions on the use of a property that may be implemented through
legal or administrative mechanisms, such as easements, to supplement the engineering controls
and minimize the potential of exposure to contaminated material remaining on site).
This report is one of several developed under the EPA Superfund Redevelopment Program to
inform stakeholders at hazardous waste sites about how EPA may take identified and potential
reuse into account when it selects, designs, and implements remedies. Other reports in this series
provide planning and design information on the reuse of Superfund sites for commercial
facilities, golf courses, and other outdoor recreational areas.
1.2 Who Should Read the Report and Why
Many entities or stakeholders have a substantial interest in the redevelopment of a Superfund
site. The potentially responsible parties (PRPs) or the owner will need to assess the impacts
of the reuse on their potential liability and the long-term stewardship of the site. In addition, a
valuable habitat could improve a company's image, provide amenities to the community, and, in
some cases, enable a land owner to trade ecological improvements for land-use concessions
elsewhere. Natural Resource Trustees may choose to assess damages from releases of
hazardous substances, pursue recoveries of damages and costs, and use the sums recovered to
restore, replace, or acquire the equivalent of the injured resource (USEPA, 1992). Local
governments may need to consider whether the proposed reuse is compatible with their land use
plans, and may benefit from increased recreational activities for their residents, tourism, and,
Section 1. Introduction
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Reusing Superfund Sites: Ecological Use Where Waste is Left On Site
consequently, tax revenues. Local citizen groups and individuals may be concerned with the
character of their neighborhood, recreational and employment opportunities, and air and water
quality. Environmental organizations are often interested in how a redevelopment project may
provide the opportunity to protect or improve local and regional habitats. EPA remedial project
managers (RPMs) and the state regulators need to coordinate remediation and reuse efforts at
Superfund sites. Consulting engineers representing the PRPs or site owners should be able to
assure regulators that the planned habitat does not compromise the effectiveness of the remedy.
To ensure that the perspectives of all interested parties are considered and that the remediation
and reuse of the site complies with all state and federal regulations, coordination with the
stakeholders should be initiated early in the planning process and continue frequently throughout
the process.
1.3 Superfund Redevelopment Program
EPA prepared this report as part of the
Agency's Superfund Redevelopment Program.
This program reflects EPA's commitment to
consider reasonably anticipated future land
uses (RAFLU) when making remedy
decisions at Superfund sites, and to ensure
that, when possible, the cleanup of Superfund
sites allows for reuse for ecological,
commercial, recreational, or other purposes
while remaining protective of human health
and the environment.
Through this program and other efforts, the
Agency works with communities to determine
remedial action objectives that will allow for
RAFLU. Land use is a local matter, and EPA
does not favor one type of reuse over another.
EPA's primary responsibility is to ensure that
the remedy is protective of human health and
the environment.
The safe and appropriate redevelopment of
sites can provide significant benefits to
communities and help ensure that remedies
will be maintained. These potential benefits
are listed in the text box. Other benefits are evident in case histories in Appendix A and several
references (WHC 2005, NC 2005, USEPA 1988, USFWS 1984).
For more information on the Superfund Redevelopment Program, including current
developments, pilot programs, tools, resources, and case studies, visit its web site at
www.epa.gov/superfund/programs/recycle, or contact the following numbers:
Ecological Reuse Provides Many
Benefits:
New employment opportunities, increased
property values, and catalysts for
additional redevelopment;
New recreational and open-space areas in
communities where land available for such
uses is scarce;
Better day-to-day property management,
leading to improved maintenance of the
remedy and continued protection of
human health and the environment;
Improved site aesthetics through the
creation of well-maintained properties and
discouragement of illegal waste disposal
and similar unwanted activities;
Better quality ecosystems, which can
contribute to improved biodiversity in local
and regional habitats and other ecosystem
services, and reduced bioaccumulation of
contaminants in plants and animals; and
Increased community acceptance of the
remedy.
Section 1. Introduction
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Reusing Superfund Sites: Ecological Use Where Waste is Left On Site
Outside the Washington, DC area: 800-424-9346;
TDD for the hearing impaired outside the Washington, D.C. area: 800-533-7672;
In the Washington, D.C. local area: 703-412-9810; or
TDD for the hearing impaired in the Washington, D.C. local area: 800-412-3323.
Hours: 9:00 AM to 5:00 PM Eastern Standard Time, Monday through Friday.
Closed on federal holidays.
1.4 Integrating Reuse Plans With Cleanup Remedies
Assumptions about the future use of a Superfund site can have a substantial impact on all aspects
of the cleanup process, from the site discovery through remedy selection and implementation.
Thus, the RPM and other stakeholders should consider assumed or planned reuse options, if they
have been identified, in the design and implementation of response actions, consistent with
Office of Solid Waste and Emergency Response's (OSWER) land-use guidance, and consider
adjusting the reuse plans or remediation approaches to accommodate each other when cost and
protectiveness are not affected (USEPA, 2001b and 1995b). When and how future land use
considerations are incorporated into EPA's site management process, and the scope of EPA's
authority to accommodate future land use throughout the remedial process, are discussed below.
1.4.1 Consideration of Future Land Uses
The anticipated future use of land is an important factor that EPA considers in identifying,
determining, and implementing appropriate response actions (USEPA, 2001b and 1995b). The
process for identifying the reasonably anticipated future land use typically begins during the
remedial investigation/feasibility study (RI/FS) or Engineering Evaluation/Cost Analysis
(EE/CA) stage of the EPA site management process. Assumptions about reasonably anticipated
future land use can be considered a part of a number of stages in the cleanup process, including:
1. The baseline risk assessment when estimating potential risk for anticipated future uses;
2. The development and evaluation of remedial or removal action objectives and response
action alternatives; and
3. The selection of appropriate response actions that can achieve the cleanup levels required
for the protection of human health and the environment for anticipated future land uses.
A useful way to develop reasonable assumptions about future land use is to conduct a reuse
assessment. The reuse assessment typically identifies broad categories of potential reuse
(e.g., residential, recreational, commercial and industrial, agricultural, ecological). The
information in this assessment may also be the starting point for the reuse planning process and
lay the groundwork for integrating the consideration of reuse into the cleanup plan. In general,
the reuse assessment can be done by the entity conducting the RI/FS or EE/CA. As with other
activities performed under the RI/FS or EE/CA, EPA, in coordination with the state, can
determine the appropriate level of oversight when PRPs perform this work. While EPA does not
expect to be involved in the details of reuse planning, the Agency should ensure that reasonable
assumptions regarding future land use are considered in the selection of a response action.
Section 1. Introduction
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Reusing Superfund Sites: Ecological Use Where Waste is Left On Site
In some cases, property owners, PRPs, and communities may have initiated a reuse planning
process. Information from a reuse plan may also be useful for the reuse assessment. As part of
the reuse assessment process, discussions are typically held between local land-use planning
authorities, local officials, property owners, PRPs, EPA, and the public to understand the
reasonably anticipated future uses of the land on which the Superfund site is located. Based in
part on these discussions, EPA develops or approves remedial action objectives and identifies
remedial alternatives that are consistent with the anticipated future land uses. If there is
substantial agreement on the future use of a site, EPA may be able to select a remedy that is
consistent with that use and take measures to accommodate it when designing the remedy.
Regardless of the site use anticipated or planned, EPA is prohibited from funding, or requiring
others to fund, certain "enhancements" to the remedy (Section 1.4.3).
EPA must balance this consideration of anticipated future land use with provisions in the
Superfund law and its implementing regulations (National Oil and Hazardous Substances
Pollution Contingency Plan, known as the NCP) which establish program management
principles and expectations to assist in the identification and implementation of appropriate
remedial actions. For example, the NCP details expectations that must be considered with regard
to using one or more of a number of approaches, such as treating principal-threat wastes,
engineering controls such as containment for low-level threats, institutional controls (ICs) to
supplement engineering controls, and innovative technologies (NCP § 300.430(a)(l)(iii)). Also,
EPA complies with other federal and state environmental laws when they are "applicable or
relevant and appropriate requirements" (ARAR), unless there are grounds for a waiver.
Once EPA selects a remedy, two general land-use situations that could result include:
If the remedy achieves cleanup levels that allow the site to be available for the reasonably
anticipated future land use, EPA strives to work within its authorities to accommodate that
reuse; or
If the remedy achieves cleanup levels that require a more restricted land use than the
preferred one, the site will probably not support the community's reuse preferences and the
interested parties will have to discuss other reuse alternatives.
For additional information on how EPA considers land use in the remedy selection process, see
EPA's Land Use in the CERCLA Remedy Selection Process, EPA OSWER Directive No.
9355.7-04; and Reuse Assessments: A Tool to Implement the Superfund Land Use Directive,
OSWER Directive No. 9355.7-06P ( http://www.epa.gov/superfund/resources/reusefinal.pdf).
1.4.2 Timing
To allow for evaluations of a variety of remediation and reuse options, any reuse planning that
might be undertaken should be initiated as early in the cleanup process as possible. The longer
reuse planning is delayed, the greater the possibility that some reuse options will be foreclosed
by decisions already made.
Generally, there are two major components of the reuse planning process: developing reuse
assessments and creating reuse plans. A reuse assessment, which typically identifies broad
categories of potential reuse (e.g., recreational, industrial, residential), is generally developed at
Section 1. Introduction
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Reusing Superfund Sites: Ecological Use Where Waste is Left On Site
the RI/FS stage. The information in this assessment may also be the starting point for additional
planning efforts, such as the creation of a reuse plan. Because the land-use categories employed
in making the assessment are usually broad, they may not provide sufficient detail to ensure that
the remedy being considered could allow for a specific use nor to efficiently be considered in the
detailed remedy design. When communities, natural resource trustees, or other parties need more
specific and detailed land-use evaluations, they may initiate the second component of the
planning processthe creation of reuse plans.
Since reuse plans are often developed after the RI/FS, they may not be available until later stages
of the site management process, such as during remedy design or construction. When EPA
receives the reuse plans prior to remedy selection, the RPM should use them in the course of
developing and evaluating the remedial alternatives. When reuse information is received after
the remedy is selected, the site manager may evaluate it to determine whether the proposed reuse
is consistent with the selected response action and whether modifications might easily be made
to accommodate the preferred reuse. Since changes in schedule or other aspects of the remedy
can affect potential risk to human health and the environment and cleanup costs, site managers
are encouraged to ensure that reuse options and plans are realistic and obtained as early as
possible.
Development of a reuse project can sometimes begin on parts of a site before construction of a
remedy is completed. This can be done by segmenting the site into different operable units
(OUs) which proceed on different schedules according to the nature of the cleanup approaches,
location, and expected completion time; deleting portions of the site from the NPL while cleanup
continues elsewhere; and sequencing the cleanup work to coordinate with development needs.
For example, at the Ohio River Park Superfund site in Neville Island, Pennsylvania, remedial
activities were interrupted when EPA agreed to make part of the site available for replacing the
old, unusable Coraopolis Bridge, which was important to the community.
In many cases, a completed remedy may not be able to accommodate the planned use without
modification because of technical, legal, or other factors. If, in the future, landowners or others
decide to change the land uses in a way that makes further remediation necessary, EPA generally
would not prohibit them from conducting additional cleanup actions, so long as the effectiveness
of the remedy is not compromised and protectiveness of human health and the environment is to
be ensured. It would likely be necessary to evaluate the implications of that change for the
protectiveness of the selected remedy. Retrofitting an existing remedy to support reuse requires
careful planning, design, coordination with, and approval by, EPA and other regulatory agencies.
1.4.3 Enhancements
EPA cannot fund, nor require PRPs or others, to fund certain "betterments"or "enhancements" of
a remedy. Generally, a prohibited enhancement is an action that is not necessary to support the
effectiveness of a remedy in protecting human health or the environment. Examples of actions
that typically may not be funded include the installation of lights for a parking lot and the
addition of extra clean fill beyond that required to make a remedy protective.
Section 1. Introduction
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Reusing Superfund Sites: Ecological Use Where Waste is Left On Site
Some cleanup activities may be necessary to accommodate the anticipated future use of a site.
Hence, it may be practicable for the Region to design, conduct, or phase response actions at a
site in a cost-neutral manner that could allow earlier reuse or maximize redevelopment potential
without adversely affecting the protectiveness of the remedy. For example, as part of the remedy,
EPA may provide corridors of clean soil or other material for future utility access when
anticipated use makes the need likely. Likewise, EPA may take future use into account in
deciding on the placement of wastes, monitoring or extraction wells, air-stripping towers, or
other treatment units, so that they do not interfere with site access or the placement of structures
needed for redevelopment of a site. Such cost-neutral actions would generally not be prohibited
enhancements.
Most efforts to revegetate Superfund sites are not considered enhancements. Grasses, shrubs, and
other plants often serve a practical function of stabilizing a soil cover and preventing erosion,
although they also improve the site's aesthetics. Some plants may clearly be part of the
remediation process through phytoremediation or as part of an evapotranspiration barrier cap
(Sections 3.1 and 3.3). However, some extensive efforts to create or restore the structure and
function of an ecosystem to exacting specifications may be considered enhancements, unless the
need for the restoration is a result of environmental stressors or damages caused by the
remediation.
EPA determines on a case-by-case basis whether an activity or feature constitutes a prohibited
enhancement. Although they cannot be funded by EPA, enhancements may be included in a
remedial action if they are consistent with and do not interfere with the protectiveness of the
selected remedy, provided that the costs are paid by another party, such as a PRP, prospective
purchaser, Trustee, or developer, and such party provides sufficient, reliable financial assurance.
1.5 Ecological Reuse of Hazardous Waste Sites
For this report, the term "ecological reuse" at cleaned up Superfund sites applies to a variety of
project types. In general, the term refers to a stable, self-sustaining ecosystem habitable by plants
and animals, and where little or no human activity is expected to occur. This definition excludes
commercial, industrial, residential, and many recreational uses. However, low-impact or passive
recreation, such as hiking or bird watching, may occur at ecological reuse areas.
Most ecologists advise that ecosystems that replicate the conditions that would have existed if
there had not been a disturbance tend to thrive best (USEPA, 1995e). However, where physical
and biological conditions are severely degraded, or where general land use or ecosystems in the
surrounding area has changed, it is difficult and sometimes impossible, to return a site to
pre-disturbance conditions.
When pre-disturbance conditions cannot be replicated, other types of significant ecosystems may
be established. The property can be returned to a stable and functioning system that "belongs" in
the region but may not be the system that predated the disturbance. Where the land is severely
disturbed, as is often the case with mining areas, the reuse can involve simply revegetating the
site with species that are compatible with the surrounding area. Ecological reuse at some sites
may entail more than one project type. Some areas of a site may be restored to relatively pristine
Section 1. Introduction
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Reusing Superfund Sites: Ecological Use Where Waste is Left On Site
condition, while other areas are simply planted with native or other compatible species. The
remediation and reuse factors discussed in this report are generally applicable to all of these
project types. However, some extensive efforts to create or restore ecosystems that are not
needed for hazard mitigation may be considered "enhancements" as described in Section 1.4.3.
1.6 Organization of Report
The remainder of this document describes planning and technical factors typically addressed
when coordinating ecological reuse with remediation activities. It includes the following:
Section 2 Planning considerations typically associated with developing, restoring, or
protecting ecosystems on a Superfund site, such as natural resource
management issues, coordination between ecological reuse efforts and the
Superfund remediation process, the role of federal, state, and tribal Trustees and
other groups, and baseline site configurations.
Section 3 Common remediation methods and ecological reuse planning and design issues
typically considered when a Superfund site is to have ecological reuse. These
issues include the characteristics of ecological resources at and near the site;
remediation system components, design, and implementation; management of
remedy construction to minimize adverse environmental impacts; potential
environmental impacts of groundwater extraction and treatment and in-situ
treatment; and the long-term maintenance of the remedy.
Section 4 Issues that often arise when wetland restoration, creation, or protection are the
primary reuse goals.
Section 5 Issues typically considered when stream restoration, creation, or protection are
the primary reuse goals.
Section 6 Issues typically considered when terrestrial ecosystem restoration, creation, or
protection are the primary reuse goals.
References References on remedy and reuse planning and design, such as EPA guidance
manuals, textbooks, and journal articles.
Appendix A Five sites where successful ecological reuse has occurred on remediated waste
sites. The discussion for each site includes its history, contamination problems,
key factors considered during remediation and reuse planning and
implementation, and lessons learned. These case studies demonstrate how
remediation and reuse efforts may complement one another.
Appendix B Acronyms
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Section 2. Planning for Ecological
Reuse of Superfund Sites
At most Superfund sites, remedies can be designed and implemented to accommodate existing or
planned plant and animal habitats and still meet all federal and state regulatory requirements.
However, some remedy features can, if not appropriately designed, have detrimental physical,
chemical, and biological impacts on local wetlands, streams, and plant and animal communities.
For example, pumping and treating groundwater may affect water, mineral, or contaminant
levels in nearby wetlands, excavation can disrupt fertile surface soils and wildlife habitats, and
the introduction of non-native species of plants and animals can adversely affect native species.
To ensure that habitats are protected, restored, or created in the course of designing and
implementing remedies, stakeholders typically consider the physical and biological condition of
the site and its relationship to local and regional plant and animal species; regulatory
requirements governing waste site cleanup and protection or creation of ecologically significant
areas; temporary and long-term ecological impacts of Superfund response actions; and the types
of habitats that are to be protected, restored, or created at and near the site.
This section summarizes key planning
factors that generally influence the
effectiveness of the remediation and
success of ecological reuse of a property
when contaminated material or long-term
treatment systems are to be left on site. It
addresses common natural resource
management issues, coordination
between ecological reuse efforts and the
site remediation process, the role of
natural resource trustees (Trustees, see Section 2.3) and other groups, and site characteristics and
configurations that affect ecological reuse.
Stakeholders will have the greatest reuse flexibility if remediation and reuse plans are
coordinated prior to remediation. Nevertheless, ecological reuse can still occur if it is not
designed until after the remedy is in place. In this situation, it is especially important that reuse
plans are based on accurate, current, as-built drawings of the remedy, rather than on pre-
construction designs.
2.1 Major Natural Resource Management Issues
Ecological reuse strategies vary widely among sites depending on the plans of nearby
communities and other stakeholders, the condition of the ecosystem at the site and adjacent
areas, state and federal regulations pertaining to specific species and habitats, the responsibility
of Trustees, and other site-specific factors. Ecological reuse planners will generally be concerned
with five broad issues: biodiversity in the area; contaminant bioaccumulation and ecotoxicity;
Key Planning Issues for Ecological Reuse:
Common natural resource management issues
Coordination of ecological reuse efforts with
the Superfund remediation process
The role of Trustees and other groups
Baseline site characteristics that affect reuse
Baseline site configurations
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the presence or potential presence of threatened, endangered, sensitive, or commercially
important species in the baseline and post-remediation; avoiding unintended consequences; and
defining the project scope.
2.1.1 Biodiversity
Biodiversity refers to the variety of all life forms: the plants, animals and micro-organisms, their
genes, and the ecosystems of which they are a part. We depend on it for our survival and quality
of life. Healthy ecosystems are necessary to maintain and regulate atmospheric quality, climate,
fresh water, marine productivity, soil formation, cycling of nutrients, and waste di sposal.
Biodiversity is required for the recycling of essential elements, such as carbon, oxygen, and
nitrogen. It is responsible for mitigating pollution, protecting watersheds, and combating soil
erosion. Biodiversity is intrinsic to the qualities we value such as physical beauty and harmony.
Plants and animals attract tourists and provide food, medicine, energy, and building materials. In
recent years, entire species and natural areas have been lost at unprecedented rates, primarily due
to human activity. The extinction of each additional species brings the irreversible loss of unique
genetic codes, which provide many benefits, such as the development of medicines and food.
The ability of a wildlife species to thrive in a
habitat is dependent upon the minimum
necessary habitat area for the species, the
minimum viable population of the species,
and the species' tolerance for disturbance. A
remediated Superfund site can help maintain
or increase regional biodiversity by
establishing connections between habitats or
by enlarging nearby habitats. Birds and large
mammals use habitat corridors for movement
among different areas. Smaller areas of
habitat that are connected by corridors
typically receive greater wildlife use than
isolated habitats. Corridors also prevent the isolation of plant and animal populations and reduce
the danger of local extinction. Thus, for sites where adjacent areas are valuable habitats, planners
can improve biodiversity by striving to create opportunities for the site ecology to support the
existing regional landscape and habitat corridors.
2.1.2 Contaminant Bioaccumulation
At Superfund sites where contaminants will be left on site after the remedy is constructed, site
managers and developers may need to address the potential for contaminant bioaccumulation in
plants and animals as well as other residual risks associated with leaving contaminants in place.
Certain contaminants (e.g., toxic metals such as copper, cadmium, zinc, and lead; organochlorine
pesticides; and a variety of chlorinated organic compounds) can become sequestered in the
tissues of organisms. The sequestering results in the organism having a higher concentration of
the substance than the concentration in the organism's surrounding environment.
A meadow provides habitat for plants, birds, and mammals
at the Army Creek Landfill site in Newcastle County,
Delaware.
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Bioaccumulation can result in increasingly greater concentrations of contaminants in the tissues
of organisms higher up in the food chain (biomagnification). These processes can result in an
organism having higher concentrations of a substance than is present in the organism's food. The
amount of bioaccumulation of a contaminant can vary widely among species.
The likelihood that contaminants of concern may bioaccumulate in food chains is one of the key
parameters examined during the ecological risk assessment (ERA). The ERA, which is an
integral part of the remedial investigation/feasibility study (RI/FS), is conducted to evaluate the
likelihood that adverse ecological effects are occurring or may occur as a result of exposure to
physical or chemical stressors at a site (1997a, 1999c). The information from the risk assessment,
supplemented with additional ecological studies that may be necessary, can be used in the design
of remedies and monitoring programs that can help avoid harmful bioaccumulation by
preventing the exposure of plants and animals to the contaminated material. For example, at the
West Page Swamp area of the Bunker Hill Superfund site in Kellogg, Idaho, root zone soil was
amended to reduce or prevent the bioavailability of many heavy metals to plants (case history in
Appendix A).
2.1.3 Threatened and Endangered Species
The goal of Superfund remedial actions is generally to protect local populations and
communities of biota (e.g., benthic species diversity), rather than to protect specific organisms
(USEPA, 1999c). Study of specific organisms is done, with some exceptions, to extrapolate
effects on these organisms to populations and communities. Thus, Superfund risk managers and
assessors should select assessment endpoints and measures that are important to sustaining the
ecological structure and function of local populations, communities, and habitats at or near the
site, or likely to be at or near the site after remediation. In addition, if specific threatened,
endangered, or commercially important species or critical habitats are present, additional
evaluations may be required under the federal Endangered Species Act or a state endangered
species act, since such laws may be ARARs. EPA's guidance on ecological risk assessment for
Superfund provides information on these and other ARARs (USEPA, 1997a, and 1999c).
Where threatened or endangered species are present, or where the post-remediation habitat might
be suitable for these species and promote their return, additional considerations should be
included in the ecological risk assessment and subsequent cleanup and reuse plans, and
coordinated with Trustees and other parties with knowledge of, and interest in, the local
ecosystems. The development of remediation and reuse plans for areas that involve threatened or
endangered species usually require the services of a professional biologist or ecologist. These
professionals can help develop creative approaches, such as methods to measure the condition of
the species without overusing destructive sampling, ways to delineate certain areas of the site to
be excluded from specific remedial activities where a threatened or endangered species only
affects part of a site, or increasing ecosystem scale by improving connectivity with other areas.
2.1.4 Potential for Unintended Consequences
Because of the diversity of factors that affect the behavior of wildlife and ecosystems, it may be
difficult to anticipate all potential consequences of a newly created or altered ecosystem. For
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example, when farmland at Lake Apopka, Florida was converted to a marsh area designed to
enhance wildlife habitat, the risk assessment anticipated no problems. However, flocks of
migrating birds converged on the newly created marsh area and hundreds of birds died of
pesticide poisoning. The birds, which were attracted by the lake, preyed on fish in nearby ditches
and small pools that were contaminated with pesticides. Another example of an attractive
nuisance is a plant that tends to attract burrowing animals, that could damage a containment
system. Project managers should understand the contaminants present and types of exposures
anticipated when developing plans to modify habitat to attract wildlife.
2.1.5 Scope of Ecological Reuse of Superfund Sites
In this report the term "ecological reuse" refers to a stable, self-sustaining ecosystem habitable
by plants and animals, and where little or no human activity is expected. As described in Chapter
1, the term includes a variety of project types, ranging from establishing ecosystems at a site that
replicate pre-disturbance conditions to simply revegetating the site with species that are
compatible with the surrounding area. A given site may require more than one type of
projectrestoring some areas to relatively pristine conditions, while simply revegetating other
parts of a site with compatible plants. Ecological reuse of a Superfund site may also involve the
need to protect, improve, restore, or create on-site or off-site ecosystems, and to allow for low-
impact or passive recreation, such as hiking or bird watching.
The scope of the reuse project is typically developed by local communities, Trustees, and other
stakeholders in consultation with EPA and other local, state, and federal agencies. Communities
and resource agencies responsible for managing lands within or near the site generally have
knowledge and experience with regional soil, plant, and ecology issues. For example,
determining which species are appropriate for local habitat conditions can be done with support
from the Natural Resources Conservation Service (U.S. Department of Agriculture
(http://www.nrcs.usda.gov), EPA's regional Biological Technical Assistance Groups (USEPA,
1991), EPA's Emergency Response Team (http://www.ert.org), and local native plant societies
(http://michbotclub.org/links/native_plant_society.htm). With cooperation among these agencies
and remedial project managers (RPMs), the planned remedy and reuse plans are likely to
successfully address local and regional natural resource management objectives and concerns.
Some extensive efforts to restore or create ecosystems may entail additional actions beyond what
is needed for a Superfund response. Although such actions may not be paid for with EPA funds,
nor may EPA require others to pay for such actions, Trustees or other parties may undertake
them and seek compensation from PRPs. It is EPA policy to coordinate EPA and Trustee
investigations of risk and resource injuries to make more efficient use of federal and state funds.
2.2 Coordinating Ecological Reuse With the Superfund Process
As discussed in Chapter 1, the future use of a property can affect all aspects of the removal and
cleanup processes. Likewise, the requirements of the remedy will generally affect many aspects
of the design and function of the ecosystems to be protected, restored, or created. The objectives
of the ecological reuse and those of the remediation are best accomplished if they are carefully
coordinated. Thus, it is imperative that the cleanup team understand ecosystem development and
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operational needs, and that the reuse team work within the Superfund site management process.
At most of the sites discussed in Appendix A (Case Studies), significant parts of the preparation
of the sites for ecological reuse were integrated with the remediation work. It is EPA's policy to
coordinate with all interested parties on establishing and implementing remediation goals that are
compatible with reasonably anticipated land uses, and to share data needed for reuse planning,
natural resource damage assessments (NRDAs), and recovery actions (U.S. EPA, 1997d, 1999c).
2.2.1 Establishing Remediation Goals
Establishing remediation goals for ecological receptors is considerably more difficult than
establishing goals for the protection of human health because of (a) the paucity of broadly
applicable and quantifiable toxicological and other necessary data; (b) the large variation in the
kinds and numbers of receptor species present at sites; (c) the differences in their susceptibility
to contaminants and recuperative potential following exposure; and (d) wide variations in
environmental bioavailability of many contaminants in different media (USEPA, 1999c).
Although the NCP establishes a protective risk range for human health, it provides little
guidance regarding developing remediation goals considered to be adequate for protecting
ecological receptors. The NCP also states that ARARs shall be considered, along with other
factors, in determining remediation goals (which establish acceptable exposure levels that are
protective of human health and the environment-Section 300.430(e)(2)(i)). For example, water
quality criteria/state standards established under Sections 303 and 304 of the Clean Water Act,
that are based on risks to ecological receptors, may be an ARAR. For these reasons, the
establishment of protective exposure levels is best done on a site-specific basis in coordination
with Trustees and other stakeholders, such as communities and property owners. Involving all
stakeholders will help to ensure that all relevant ecological resources are identified and
considered in all phases of planning and implementing Superfund response actions.
Superfund response actions may not lead to the ecosystem contemplated by communities or
Trustees and these parties may wish to undertake additional activities to protect or restore an
ecosystem. Although such additional activities may not be EPA's responsibility, it is EPA's
policy to coordinate its investigation of risk with the Trustees' investigation of resource injuries
and reuse potential in order to most efficiently use federal and state funds and not duplicate
efforts (USEPA, 1999c). Data collection efforts should be coordinated with other efforts to
collect data for human health risk assessments or for NRDAs. Many data elements are common
inputs to all these efforts.
It is not always necessary to completely remove contaminated material from a site to reduce
ecological risk to acceptable levels. EPA may seek to develop remedies that reduce the
contaminant's media exposure concentrations below ecotoxicity values, reduce the
bioavailability of the contaminant to plants and animals, and interrupt the exposure pathways.
For example, a protective cap may prevent exposure of certain species to subsurface
contaminated materials or soil amendments may reduce the bioavailability of some contaminants
to plants and animals. Sometimes the removal of contaminants could cause more harm than
leaving them in place.
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2.2.2 Ecological Risk Assessment and Natural Resource Damages
Ecological risk assessments, which are conducted as part of the RI/FS phase of the Superfund
response process evaluate the likelihood that adverse ecological effects are occurring or may
occur as a result of exposure to physical or chemical stressors. These assessments often contain
detailed information regarding the interaction of these stressors with the current biological
community at the site and the future biological community anticipated under the anticipated land
use. Part of the assessment process includes creating exposure profiles which describe the
sources and distribution of stressors and exposure pathways; estimate the intensity and extent of
exposures at a site; evaluate toxicity, bioaccumulation, mortality, reproductive impairment,
growth impairment, and loss of critical habitat; and identify sensitive organisms or populations.
An ERA can be conducted quickly for a removal action, should there be an imminent threat to
ecological receptors. However, these instances are rare and these risk assessments follow the
same process outlined for long-term ecological risk assessments conducted during the RI/FS.
EPA has published both Agency-wide guidance for ecological risk assessments (USEPA, 1998b)
and Superfund Program-specific guidance (USEPA 1997a and 1999c).
Ecological risk information from the RI may be relevant in a NRDA and both EPA and Trustees
generally benefit from sharing information and coordinating with each other during ecological
risk assessments. EPA guidance requires coordination among EPA and all affected Trustees in
site characterization, response actions, and settlement negotiations (USEPA, 1997d). The
guidance also calls for Superfund site risk managers and Trustees to coordinate both EPA
investigations of risk and Trustee investigations of resource injuries to make efficient use of
federal and state funds.
An NRDA is used to identify additional actions, beyond the response, needed to address injuries
to natural resources. Examples include actions needed to restore the productivity of habitats or
the species diversity that were injured by the past releases or to replace them with substitute
resources. A Trustee may also seek compensation for the loss of injured natural resources from
the time of injury until the time they are fully restored. Regulations for assessing natural resource
damages have been promulgated under both the Comprehensive Environmental Response, and
Compensation and Liability Act (CERCLA) and the Oil Pollution Act (OPA).
2.2.3 Typical Ecological Reuse Development Process
EPA generally does not determine land use. Land use planning is generally conducted by
communities with input from Trustees, and other stakeholders. Nevertheless, it is useful for EPA
and others involved with the remediation to understand typical topics that are addressed when
planning and implementing an ecological reuse project. It is best to develop a potential reuse
plan early in the Superfund cleanup process. If the reuse option is identified early, planning for
both the ecological reuse and remediation can be done concurrently. If the reuse option is not
determined early enough, additional work may be needed to plan for and establish a viable
ecosystem. In either situation, ecological reuse planning involves the following general steps.1
1 Adapted from U.S. Department of Interior 1998, National Research Council, 1992, Federal Interagency Stream
Corridor Restoration Working Group 1998, and Kent 1994.
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Determine pre-disturbance and reference conditions. Reuse planners can determine the
pre-disturbance ecological characteristics and condition of a site by using historical records
and maps and by studying nearby undisturbed areas with similar physical characteristics.
This information can help develop reference conditions used for establishing reuse goals and
objectives, and provide a model for creating ecological processes that will thrive at the site.
Conduct site inventory/characterization. A site inventory and characterization should
include mapping the site, documenting its condition, evaluating the type and degree of
disturbance (type, concentration, and areal extent of waste and physical damage) and the
degree to which pre-disturbance ecological processes were affected by the disturbances. It is
important to develop a thorough understanding of the structure and function of the on-site
and associated off-site ecosystems, and to determine the current condition of habitats,
sensitive ecosystems, wildlife populations, drainage patterns, water bodies, roads, adjacent
properties, and other factors that could be affected by the remediation and future land uses.
Data will be needed on soil characteristics (compaction, tilth, carbon nitrogen ratio,
nutrients), water quality and quantity, geomorphology, plant and animal communities, and
threatened and endangered species. Much of the information may already be available from
data collected as part of the RI. If the RI team has no plans to collect data on some critical
parameters, reuse planners may coordinate with EPA to arrange for such data.
Establish reuse goals and objectives. Reuse planners should develop a statement of goals
for the ecological reuse project which describes the site conditions to be achieved (e.g.,
restore a degraded wetland to its pre-disturbance species diversity). Reuse objectives are
usually more specific measures to achieve those broader goals (e.g., establish selected
species at a desired frequency and density within a prescribed time frame).
Evaluate reuse alternatives. One or more alternative approaches to site reuse should be
evaluated, and a preferred alternative should be selected, in consultation with EPA.
Develop site-specific ecological design. After the preferred reuse alternative is determined,
reuse planners then proceed to develop a detailed plan for the reuse design.
Prepare specifications for construction contractors. Based on the final approved reuse
design, the specifications are used to solicit contractor support.
Construct the habitat features. Oversight during construction of a reuse project is essential
to ensure that the work is conducted according to the reuse design specifications and that
any modifications are made appropriately. It is advisable, in many situations, to have an
ecologist or biologist and remediation professionals available during construction to monitor
progress and suggest modifications if unexpected conditions are encountered.
Maintain site. After construction is complete, tasks such as periodic inspection of remedy
components and habitat features and repair and replanting after flood damage are often
needed to sustain the ecosystem. Generally, more intensive maintenance is needed for the
first three to five years after the initial construction than in later years.
Monitor results. A monitoring plan should be developed based on the initial sampling in
the site inventory and characterization and the reuse design. Prior to beginning the reuse
work, reuse planners may want to establish photopoints and permanent markers for
monitoring sites that can be reestablished during and after the reuse project.
Many of the above reuse-related activities can be coordinated with the Superfund response.
Section 2.2.4 indicates points in the Superfund process where Trustees are to be involved.
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2.2.4 Superfund Site Management Process
The Superfund cleanup process begins with the discovery of hazardous waste or notification to
EPA of possible releases of hazardous substances. Once discovered, EPA or another lead agency
investigates the potential for a release and, if necessary, conducts or oversees a remedy. The
following are the primary phases of the CERCLA remedial process and the ecological reuse
considerations that accompany each phase.
Site Discovery. After a site is reported, EPA conducts an initial screening to determine
whether further assessment is warranted, and exchanges information with Trustees regarding
PRPs and CERCLA §104 requests and invites them to be involved in the response.
Preliminary Assessment/Site Investigation (PA/SI). The EPA Region performs a
preliminary assessment (PA) and site inspection (SI), or an integrated or combined PA/SI to
provide information on site conditions that typically allows a determination to be made of
whether a site's preliminary score is sufficient for possible listing on the NPL. EPA
coordinates assessments, evaluations, investigations, and planning with Trustees and
provides them with an opportunity to participate in health and ecological risk screening.
Hazard Ranking System (HRS) Scoring. This scoring is a screening mechanism used to
decide whether a site is eligible to be considered for National Priorities List (NPL) listing.
NPL Site Listing Process. This process allows for public comment prior to listing a site on
the NPL, after which it is considered a Superfund site. EPA provides Trustees with national
lists and site-specific information supporting the NPL listing.
Remedial Investigation/Feasibility Study. In the RI/FS, EPA determines the nature and
extent of contamination and its fate and transport, and identifies risks and cleanup
alternatives. During this process, the lead agency or other party may conduct a reuse
assessment to develop assumptions about reasonably anticipated future land uses (USEPA,
2001b). It is EPA's policy to coordinate the activities in this step with Trustees (NCP
§300.430(b)(7)) and communities, and other interested or affected parties ((NCP
§300.430(c)). EPA coordinates necessary assessments with Trustees and provides
opportunity for Trustees to comment on work plans, RI/FS reports, remedial alternatives,
ARARs, and the proposed plan and Record of Decision (USEPA, 1999c).
Record of Decision (ROD). This document describes the selected remediation approach
and the rationale that led to the decision. The remedy selection process involves a
comparative analysis of alternatives with respect to the nine remedy-evaluation criteria
specified in the NCP and the compatibility of a remedy with reasonably anticipated future
land uses. The process is used to determine which alternative is most appropriate for the site
and the anticipated land use(s). EPA provides Trustees the opportunity to review and
comment on negotiated draft agreements, as well as a final copy of the ROD.
Remedial Design/Remedial Action (RD/RA). When designing and implementing the
remedy, RPMs should, to the extent practicable, strive to accommodate the anticipated
future land uses consistent with the remedy, subject to regulations regarding enhancements
(Section 1.4.3). When addressing ecological resources, RPMs should work with
communities and local groups, Trustees (Section 2.4) and other organizations to develop
remediation and reuse projects. It is EPA's policy to invite and encourage Trustee
involvement in planning response actions, negotiate with PRPs, and review draft work plans
and RD/RA documents.
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Construction Completion. After the construction of the remedy is completed, EPA and
states can take steps to prepare for operation and maintenance, accommodate future uses,
and help remove potential obstacles to reuse. If, during this phase of the remedial process,
landowners or others propose to change the land use, RPMs and states play an important
role in evaluating the implications of that proposed change on the original remedy, and
determining whether or not modifications to the remedy are warranted.
Operation and Maintenance (O&M). After construction is completed, O&M activities,
which should be specified in the ROD, are undertaken to ensure that the remedy is effective
and operating properly over time. EPA typically provides Trustees the opportunity for
comment on O&M plans. At some sites, a Trustee may implement the O&M plan.
NPL Site Completion/Close-Out/Deletion. When all cleanup activities at a site are
completed, RPMs will need to document that the engineering and institutional controls are
in place and that the site, or a portion of the site, is ready for the planned or anticipated use.
The site may then be removed from the NPL. EPA provides Trustees the opportunity to
participate in close-out activities and comment on the draft close-out report.
Five-Year Reviews. Where waste remains on site at levels that do not allow for unrestricted
use and unlimited exposure, EPA or other authorized organizations generally conduct formal
reviews at least every five years to determine whether the remedies remain protective of
human health and the environment. Copies of the five-year review are provided to Trustees.
2.3 Natural Resource Trustees and Other Organizations
The cleanup and successful ecological reuse of a Superfund site is facilitated by coordination
among various EPA program offices, offices of other federal and state agencies, and other
stakeholders. Many of these entities have information and technical expertise about local
ecosystems and the biological effects of hazardous substances. Some entities, such as Trustees,
have been authorized to act on behalf of the public as stewards of natural resources.
2.3.1 Natural Resource Trustees
CERCLA and the OPA authorize the United States, states, and Indian Tribes to act on behalf of
the public as Trustees for natural resources under their respective trusteeship [CERCLA
§ 107(f)(1); OPA § 1006(c)]. Section 300.600 of theNCP designates the secretaries of the
following agencies to act as Trustees for the natural resources, subject to their respective
management or control: the Departments of Interior (DOI), Agriculture (USDA), Commerce
(DOC), Defense (DOD), and Energy (DOE). State and tribal Trustees, which are usually the
heads of agencies responsible for environmental protection or fish and wildlife management, are
designated by their governors or tribal chairpersons. Links to specific information about each
secretaries' responsibilities and state programs can be found on the EPA web site
(http://www.epa.gOv/superfund/programs/nrd/trust_r.htm#state).
CERCLA and OPA contain authorities to allow the assessment and restoration of natural
resources that have been injured by a hazardous substance or oil release or response. EPA is not
a Trustee, nor is it authorized to negotiate on behalf of Trustees. However, CERCLA requires
coordination with all affected Trustees, and an even greater coordination with federal Trustees,
in site characterization, response actions, and settlement negotiations. As part of its response
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responsibilities, EPA is required to notify Trustees of potential injuries to natural resources from
releases under investigation, coordinate assessments, investigations, and planning with Trustees,
notify trustees of compliance and enforcement actions affecting injuries to natural resources
under their jurisdiction, and encourage the participation of federal Trustees in settlement
negotiations (CERCLA § 104(b)(2), § 122(G)(1), and USEPA,1997d).
Trustees often conduct NRDAs for the purpose of determining the extent and value of injury or
loss of natural resources. Some of the ecological studies that support NRDAs may also be useful
to Superfund site managers who are conducting or directing RIs, including ecological risk
assessments for the remediation process. However, the NRDA's may not be available until after
the RD/RA is underway, and may not provide all the information needed by the RPM. Although
many data elements will overlap, the objectives of the two efforts are different. Nevertheless,
Superfund site managers are encouraged to consult and coordinate with the Trustees when
conducting RIs. Often, the information from the RI is available prior to the NRDA, and it is
EPA's policy to coordinate the activities in this step with Trustees (U.S. EPA, 1997d). Critical
portions of the ecological information from these assessments may be useful to stakeholders in
planning for the future use of a site and assessing and recovering damages. EPA typically
coordinates necessary assessments with Trustees and provides opportunity for Trustees to
comment on work plans, RI/FS reports, remedial alternatives, ARARs, and the proposed plan
and ROD (USEPA, 1997d).
EPA has no authority or responsibility to negotiate on behalf of Trustees (USEPA, 1992). The
Trustees and other stakeholders may request restoration, replacement, or acquisition of habitat as
compensation for damaged resources. These restoration actions become the responsibility of the
Trustees or other stakeholders. With proper coordination, however, it may be advantageous to all
parties to combine the Trustees' restoration or other actions with remediation-related activities
conducted by PRPs or EPA. Such coordination should be planned carefully because CERCLA,
as amended by SARA Section 517, places restrictions on the use of Fund monies for NRDAs and
subsequent implementation of restoration activities to compensate for damages (USEPA, 1992).
In addition, EPA is prohibited from funding, and cannot legally require PRPs or others to incur
extra costs beyond those necessary to ensure protection of human health and the environment, as
explained in the discussion on "enhancements" in Section 1.4.3. Some extensive efforts to create
or restore an ecosystem to exacting specifications may be considered enhancements, unless the
need for the restoration is a result of the response actions, such as to repair damage done by
excavation for the response action.
2.3.2 Biological Technical Assistance Groups and Other Agencies
A Regional Biological Technical Assistance Group (BTAG) can provide a useful mechanism to
advance coordination among different EPA program offices, other federal agencies, and state
programs. The BTAG is a group of scientists from EPA and other agencies that provide technical
assistance and promote coordination on ecological issues at Superfund sites (USEPA, 1991).
Each EPA Region has a BTAG coordinator. Some regions use a different name for the BTAG
such as Ecological Technical Assistance Group or Superfund Ecological Assessment Team.
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Valuable interagency partnerships have also been developed for coordinating planning efforts at
individual Superfund sites. At Loring Air Force Base in northeastern Maine, for example, project
managers recognized that large-scale RAs in Greenlaw Brook would severely disrupt sensitive
and valuable habitat on the site. During the planning phase, the U.S. Air Force, in conjunction
with EPA, U.S. Fish and Wildlife Service (USFWS), and the Maine Department of Environment,
developed a Wetland Mitigation Process Plan. This plan outlined strategies for minimizing
impacts to wetlands due to RIs and RAs. The plan drew upon the unique expertise and interests
of each partner, and established an atmosphere of cooperation between interested parties.
Several government agencies and private interests are involved in cleaning up the Rocky
Mountain Arsenal, near Denver, Colorado. Rocky Mountain Arsenal is a large and complex
Superfund site covering 27 square miles. Shell Oil Company, the U.S. Army, EPA, the Colorado
Department of Health and the Environment, and USFWS are all involved in planning site
remediation. To balance the interests of these parties and ensure effective collaboration among
them, an engineering group with representation from all five parties meets on a regular basis to
coordinate the technical aspects of remedial activities. In addition, a revegetation group
addresses planning activities relevant to ecological restoration at the site.
2.4 Site Characteristics That Affect Ecological Reuse
Information on a number of site characteristics is typically used to determine the condition of the
site and the potential for ecological reuse. These variables should be considered during the
process of planning, designing, and implementing the remediation and reuse projects. The most
common variables are listed below.
Size of site: Generally the larger the site, the greater the likelihood that it will contain the
minimum acreage necessary to sustain healthy populations of desired species. However,
even small spaces can provide valuable green space.
Existing habitat at the site: The less disturbed the existing habitat at a site, the greater the
potential for successful ecological reuse.
Proximity to existing undisturbed areas: Natural areas that are adjacent to or near the site
can effectively increase the habitat area available for some desired species and improve the
ability of the remediated site to sustain healthy populations. Also, less initial planting is
required as naturally occurring in-fill by adjacent plant species will tend to occur.
Surrounding land uses: The impacts of surrounding land use activities (e.g., crop
agriculture, grazing, urbanized areas) can significantly affect the potential for restoring a
functioning natural system at the site.
Topography: It is often challenging to establish viable habitats on sites with very steep
slopes or other extremes in topography.
Hydrology: Sites where a natural water supply is available, or can be reestablished, tend to
have greater potential to achieve a natural, self-sustaining system than sites where
engineering structures will be needed to manage water flows.
Access to the site: A site's potential to achieve the expected natural functions is improved
where public access can be managed through institutional controls (ICs) or other measures
(e.g., to prevent future damage from off-road vehicle use).
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Biodiversity: An ecosystem's functions can be enhanced by incorporating features to ensure
a minimum habitat size, such as habitat corridors. The importance of biodiversity to local
and regional ecosystems is discussed above (Section 2.1.1).
Contaminant bioaccumulation: The ecological impacts of the accumulation of certain
contaminants in the tissues of organisms is discussed above (Section 2.1.2).
Indicators of health of species and ecosystems. Measures, such as the baseline ecotoxicity
levels and post-construction levels anticipated are used.
Threatened or endangered species. These species will require special attention to ARARs,
such as the Endangered Species Act or state endangered species acts.
Information on these variables can contribute to the evaluations of the availability of food, water,
shelter, and living space, all of which vary by species. Some wildlife require running water,
some require stagnant water, and some get their water from dew. Shelter is needed to provide
protection from predators and the weather as well as areas for feeding, breeding, and resting.
A restoration ecologist may be needed to evaluate this information. The primary sources of data
on these variables are the ecological risk assessments prepared as part of the Superfund process,
NRDAs, and other studies prepared by Trustees and other parties. The ecological risk assessment
typically identifies key contaminants and ecological receptors of concern including threatened
and endangered species; critical habitats and wildlife migration corridors; and ecotoxicity values
for the receptors of concern. Other assessments of natural resources at a site are often conducted
by Trustees, such as the Department of Interior (DOI). These studies can be used to identify and
describe environmental resources and constraints and to ensure that the remedy and the selected
reuse minimize disturbance to ecological receptors, critical habitats, and historic resources.
Redevelopment of urban sites generally employs the same general considerations discussed
above. Urban sites may also require special considerations in the selection of species and habitat
design. Many urban waste sites are small, which calls for species that do not require large
territories. Other urban and suburban sites, such as old landfills, shoreline, and riverside
properties, may be the largest remaining tracts in the area. Urban areas may be subject to heavy
runoff containing high concentrations of pollutants, because of an abundance of impervious
surfaces, such as roads and parking lots. Furthermore, ecologists must consider that ambient air
temperatures in urban areas are often warmer than in rural areas. A number of ecologists have
examined the types of species and habitat design considerations for urban areas, and sources for
further information are included in the References, which begin on page 61 (Clemants, 2002;
Robinson and Handel, 1993; Handel, 1997 and 2003).
2.5 Site Configurations
Remediation approaches and the potential for ecological reuse differ according to whether the
contaminated materials are left in place, placed in a new containment system created as part of
the RA, or treated over time with special structures or equipment that remain on site after the
initial remedy construction is completed.
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2.5.1 Closed-in-Place Sites
Sites where the materials are left in place, primarily include municipal or industrial landfills,
some large surface impoundments, and mine tailings accumulations. Site managers and
developers for many of these sites have to deal with conditions such as the potential for
substantial subsidence or differential settlement, gas production, and very hazardous materials
remaining on site. These facilities frequently lack bottom liners and, if covered, the covers may
be poorly designed. There are generally few remedial options for old landfills and other existing
waste depositories that are to be closed in place. The presumptive remedy for these sites involves
containing the waste, installing a protective cover, treating or controlling contaminated
groundwater, leachate, and gas, and implementing institutional controls (U.S. EPA, 1993c). Key
ecological issues at these types of sites include the types of vegetation over and near areas
containing waste, the management of groundwater and surface water, the presence of gases, and
settlement. These issues, and other concerns are discussed in Section 3.
Many closed-in-place sites have been developed into ecological reuse areas. For example, the
Bowers Landfill in Pickaway, Ohio now contains meadows and a wetland that are habitats for
waterfowl and other species. At the Fresh Kills Landfill in Staten Island, New York, the largest
municipal landfill in the world, grass, shrubs and trees with shallow root systems have been
planted in about two feet of fill placed above the landfill cover. The trees are attracting birds,
which are expected to carry seeds from the surrounding area, thereby increasing the biodiversity
of the area's flora. Once the vegetation is established, hiking and biking trails are planned.
There are a number of mining sites, especially in the West, where extensive tailings deposits
have not been removed or fully treated in place. These tailings often contain levels of metals that
are sufficiently high to be toxic to both flora and fauna, leaving the area a virtual wasteland. By
covering and/or amending the surficial tailings with a mixture of biosolids, lime, or other
materials that will increase the pH, EPA and its partners have been successful in providing a root
zone that will support native plants as well as greatly reduce the bioavailability of the metals. At
Leadville, Colorado large tracts of tailings that previously did not support plant life have now
been turned into meadows using composted biosolids and lime, which allow for a more
hospitable growing environment. The soil amendments reduced toxicity by immobilizing the
metals, increasing fertility, and raising the pH. While the materials beneath the cover layer
remain toxic and should not be disturbed, the meadowland plants provide cover and safe food for
a variety of animals.
2.5.2 New Containment Systems
New containment systems generally are those that are created as part of the remediation. These
systems range from simple unlined pits with covers to highly engineered depositories into which
waste from the site or other sites are consolidated. A new containment system may also include
material that has been solidified or stabilized ex situ. High-hazard wastes are generally treated or
sent to an off-site commercial disposal facility and not placed into new containment systems.
Engineered containment systems generally do not have serious differential or general settlement,
subsidence, or gas production problems. As part of good construction practice, the materials
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should be compacted as they are placed into this type of containment system. A minimum
amount of compaction may be necessary to minimize settling of the cover. A 2002 EPA report,
Reusing Superfund Sites: Commercial Use When Waste is Left On Site (EPA, 2002), discusses
factors to consider if additional compaction is required to accommodate staictures.
When addressing new containment systems, EPA site managers generally have more flexibility
in deciding which materials will remain on site and in designing and locating containment areas
than they do with existing waste depositories. This flexibility generally allows for a greater range
of development options. In designing cleanups, the site manager generally considers factors such
as the types of contaminants, their stability, the media through which they travel {i.e., air, soil,
groundwater), and the anticipated future land use. For example, engineered containment areas
could be located where they will not interfere with ecological functions and structure. At the
Cherokee County Galena Subsite in Cherokee County, Kansas the remedy included
consolidating surface mine wastes in abandoned mine pits, mine shafts, and subsidence areas
where they could be covered with clean soil and the surface could be recontoured and planted
with specially selected mixtures of native prairie
grasses. The tall, wavy grass now harbors birds
and small mammals, has improved the aesthetics
of the area, and controls run off and erosion.
Another approach to protecting the contaminated
material from periodic events such as flooding is
to place clean fill above it so that flood waters
will not pool on top of the cover, and use
vegetation, riprap or other appropriate surface
material to hold the fill in place. At the Ohio
River Park Superfund site in Neville Island,
Pennsylvania, an average of eight feet of fill was
placed on parts of the site to raise the elevation
above the 100-year flood plain. This fill is
designed to protect subsurface materials from erosion and to provide a clearance of clean soil in
which to place utilities. When these types of approaches are used, a good safety measure is to
place visible barriers, such as colored soil or brightly colored synthetic geotextile material,
between the contaminated material and the clean fill to act as markers for future workers.
Building new containment systems usually effectively removes existing biota. Revegetation over
containment areas or treatment systems must not detract from the effectiveness of the remedy.
Features that could damage the containment system or attract nuisances, should be avoided. For
example, some deep-rooting plants can damage a protective cap and some plants can attract
burrowing animals. There should also be enough soil above the protective cover to allow for the
intended vegetation. The containment system can be designed to discourage wildlife from
coming into contact with the contaminated material or from damaging a containment area. At
Rocky Mountain Arsenal, project managers are designing biota barriers to keep burrowing
animals, such as badgers and prairie dogs, away from the containment areas. These concrete
cobble barriers are installed around landfills and other containment areas on the site.
Native Grasses thrive in clean soil placed above
consolidated mine wastes at the Cherokee County,
Kansas site
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Section 3. Remediation Considerations
for Ecological Reuse
There are numerous site remediation approaches that can be used to ensure that contaminated
material left on site is managed and contained in a manner that protects human health and the
environment, complies with federal, state, and
local cleanup requirements, and allow for safe
ecological reuse. The most common methods
are cover systems, gas collection and treatment
systems, groundwater collection and treatment
systems, permeable reactive barrier walls, and
diversion walls. Each of these methods can
impact ecosystems such as wetlands, streams,
and other areas to be vegetated.
3.1 Containment System Covers
Cover systems at containment sites are generally used to minimize the infiltration of water into
the contaminated material and to serve as protective barriers to isolate contaminants from the
public and the environment. CERCLA requires that cover systems at Superfund sites attain, at a
minimum, applicable or relevant and appropriate requirements (ARARs). Common ARARs for
containment systems are regulations promulgated under Subtitles C and D of the Resource
Conservation and Recovery Act (RCRA) and state regulations when they are more stringent.
Although cover systems at Superfund sites are not necessarily based on RCRA closure
regulations, RCRA requirements are the prevalent basis for cover system design. RCRA and
state regulations generally require that the cover be built to:
minimize the migration of liquids over the long term,
function with minimum maintenance,
promote drainage and minimize erosion, and
accommodate settling and subsidence.
EPA encourages flexibility in the design of waste site covers. They can range from a simple soil
or asphalt layer to protect people from contact with the contaminants, to multi-layered composite
caps often used for more demanding situations. General design requirements are based on
federal and state criteria.2 Cover systems can utilize one or more of the following types of
barriers:
Key remediation issues for ecological
reuse sites:
Common containment system components
Remediation technologies
Remedy planning and design
On-site waste treatment and monitoring
Minimizing damage from construction
Ensuring the short-term and long-term
effectiveness of the remedy
2 For example, the RCRA Subtitle C closure requirements for hazardous waste management facilities (40 CFR
264.10).
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Hydraulic barriers, the most common of the five cover types, use low-permeability material to
impede the downward migration of water. They are usually multi-layered systems that typically
incorporate geomembranes,
geosynthetic clay liners,
compacted clay liners, or a
combination of these. These
systems may also include features
such as a gas venting layer, biota
layer to prevent damage from
burrowing animals or plant roots,
drainage layer, and a soil and
vegetative or other top layer.
Multi-layered hydraulic barriers
are used at many RCRA Subtitle C
and D facilities.
Capillary barriers are intended
for use in arid to semi-arid
climates where unsaturated soil
conditions prevail. This type of cover exploits the difference in pore water pressure potential
between fine and coarse grained soils to limit the downward movement of water. A simple
configuration of this type of cover system consists of a fine-grained soil (clay) layer located over
a coarser-grained soil (sand) layer. Under unsaturated conditions the fine-grained clay holds
water, preventing its downward movement. As the top layer becomes saturated, it releases water
to the lower layer.
Evapotranspiration barriers are also used predominantly in arid and semi-arid areas. This type
of cover generally consists of a thick layer of relatively fine-grained soil which is capable of
supporting vegetation. It provides sufficient water storage capacity to prevent water from
moving into the waste area and contains the water until it is removed by evapotranspiration.
Direct contact barriers provide a physical barrier over contaminants that are contact or
ingestion hazards. They are typically up to three feet thick, but can be thicker. They also provide
protection against erosion and shallow digging. Soil covers are often economical because they
typically consist of low-cost fill materials covered with a few inches of topsoil to support
vegetation. These types of covers are commonly used with contaminated soil that has been
stabilized or material that is unlikely to migrate to groundwater, such as low-solubility metal or
asbestos.
Amended waste covers are used when the contaminant mass is too large to move and when it
would be impractical or ecologically damaging to provide a sufficient quantity of borrow soil to
cover the contaminated material, such as on some areas containing mine tailings. The
amendments may include mixtures of biosolids, wood chips, other organic matter, and lime or
other material that will raise the pH. These mixtures will support plants which, in turn, reduces
water and wind erosion and decreases the bioavailability of the metals. Amended covers are not
Placement of a geotextile layer at the Loring Air Force Base site
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a barrier against burrowing animals, but they do reduce contact exposure for larger animals and
birds while providing them with a stable ecosystem.
Depending on site-specific conditions, cover systems may be composed of multiple layers of
natural and/or synthetic materials, each designed for one or more specific purposes, such as gas
control, internal drainage, and vegetative support. In addition, the impact of cover systems on the
local stream flows should also be considered. The References (page 61) lists a number of EPA
documents that address cover system function and design.
3.2 Other Containment System Components
Liner systems are barriers that are typically constructed at the bottom of containment cells to
prevent the migration of contaminants to the environment. Liner systems prevent leachate and
gases produced in the subsurface from contaminating adjacent soil and groundwater. Liners
usually consist of hydraulic barriers fabricated with clay or geomembranes, depending on local
geology and environmental requirements. Most waste depositories in the Superfund program,
such as old landfills, do not have liners.
Leachate collection systems control the movement and prevent the buildup of leachate within a
containment system. Leachate is produced when water percolates through contaminated material
and carries biological and chemical constituents into the bottom of the containment system.
These containment systems typically consist of high hydraulically conductive soil (e.g., sands
and gravels) and perforated pipes located between the contaminated material and the bottom
liner. Leachate collection systems are typically sloped one to five percent toward a sump. A
pump is used to extract the leachate from the sump. Most old containment systems at Superfund
sites do not have leachate collection systems.
Gas collection systems are incorporated into the cover system to control the movement and
prevent the buildup of harmful gases within the containment system. Gas collection and
treatment systems are generally associated with sites that have decaying organic matter, such as
municipal landfills. Two common types of systems are passive and active. Whether these
systems are complex or simple, the location of vents, discharge points, and treatment systems
can generally be chosen so that they do not interfere with the ecological use of the property.
3.3 Associated Remedial Technologies
Several remedial technologies can be used at a site alone, or in conjunction with a cover system
remedy. Because groundwater contamination is present at most Superfund sites, the majority of
these technologies are for groundwater remediation. The following are some of the more
common types of technologies associated with containment systems.
Groundwater Extraction and Treatment Systems. Groundwater extraction and treatment
systems, also referred to as pump-and-treat systems (P&T), are used to remove contaminated
groundwater to above-ground facilities for treatment. P&T systems typically consist of
extraction wells or french drains. Extraction wells can be deployed in most hydrogeologic
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situations, while french drains are generally limited to shallow, low hydraulic conductivity
aquifers. There are a number of additions and variations to a typical P&T system that can
enhance performance or target other media such as soil. They include in-situ technologies, such
as dual phase extraction, soil vapor extraction, and air sparging; and ex-situ technologies, such as
air stripping, carbon adsorption, metals removal, and biological treatment.
P&T systems cause less surface disruption than excavation. However, if not designed carefully,
overpumping can cause adverse effects on existing and anticipated habitat. Overpumping occurs
when groundwater is extracted at a greater rate than it can be replenished or naturally recharged.
Some important design considerations for P&T remedies in ecological reuse areas are preventing
the dewatering of wetlands {i.e., resulting from lowering of the water table), avoiding alterations
in site hydrology {e.g., stream flow reduction which can also result from a lowering of the water
table), preventing land subsidence, and managing the discharge or disposal of treated water
(USEPA, 1993b). In cases where process water is discharged to surface waters, site managers
should consider the ecological impacts of the discharge. Compliance with discharge permit
provisions, where they are required, does not guarantee that there will not be any adverse
impacts on sensitive species in wetlands or streams. The discharge of large quantities of water
may result in changes in water depth, turbidity, circulation, and temperature. Species that cannot
adapt to these changes may disappear. To mitigate these potential effects, measures, such as the
use of settling basins, can be employed to moderate discharges to wetlands and streams.
Although subsidence is more often associated with large well fields than with P&T systems, it is
potentially an issue with larger P&T projects. Subsidence typically occurs slowly and often can
affect a large area around a P&T system. It can alter site hydrology by increasing or decreasing
stream gradients and changing stream flow. Such alterations in hydrology can result in loss of in-
stream or riparian habitat, and alter the water flow into wetlands, thereby impairing their
function. To avoid overpumping, RPMs should design a pump-and-treat remedy so that the
aquifer's recharge rate at least equals the rate of groundwater withdrawal. Methods are available
to estimate the extent of water table drawdown and land subsidence that will result from the
groundwater extraction. Additional information on characterizing aquifer hydraulic properties
and pump-and-treat guidance is available in EPA's Presumptive Response Strategy andEx-Situ
Treatment Technologies for Contaminated Groundwater at CERCLA Sites (USEPA, 1996a).
In addition to wells and drains, collection and treatment systems require piping, utilities, and on-
site or off-site treatment facilities. Access for operation and maintenance (O&M) may be needed
throughout the life of the systems, which may be in place for many years. Careful consideration
of the location of treatment wells and equipment can help maximize the potential for habitat
formation and biodiversity, and minimize the disruption from future maintenance activities. To
the extent that the site manager has flexibility in placing this equipment, he/she may consider
potential ecological reuse scenarios or land use plans, if any are available. For example, based
solely on engineering criteria, the optimal location for an on-site water treatment plant at the
Petro-Chemical Systems, Inc. (Turtle Bayou) Superfund site in Liberty County, Texas, was in a
grove of live oaks. These 150-year-old live oaks, which form the backbone of a unique
ecosystem that provide habitat for plants and animals on site, are sensitive to physical disruption
around the root zone. To prevent damage to the live oaks and the unique ecosystem they support,
the water treatment plant was located in an abandoned rice field about 1,000 feet away, where
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the ecological impacts would be comparatively minimal. The ecological benefits were significant
enough to justify the additional expense.
In-Situ Treatment. In-situ treatments use biological, thermal, and physical/chemical processes
to treat contaminated material in place, without excavation. Because in-situ treatments require
less surface disruption, they allow the preservation of critical ecosystem components, such as
vegetation and topsoil. For example, at the French Limited Superfund Site in Harris County,
Texas, the use of in-situ bioremediation enabled the project manager to minimize disturbance to
the surface, thereby preserving site topography, existing vegetation, and natural drainage
patterns. This approach allowed the site to be used as a freshwater wetland.
Some in-situ treatments require the addition of amendments, such as aqueous extracting
solutions, nutrients, or chemicals to the contaminated media. Project managers should evaluate
their effects in the subsurface, their potential for eventual transport to surface waters, and their
possible subsequent adverse effects on plant and animal communities.
Diversion Walls. Diversion walls are below-grade vertical structures designed to divert
groundwater flow away from contaminated material or to contain contaminated groundwater.
Diversion walls can be grouped into three types: sheet pile, grout, and slurry. Of the three types,
slurry walls are the most common. These structures are also used in conjunction with covers to
fully confine a waste area and to prevent clean water from leaching through the material.
Diversion walls are generally, but not always, associated with groundwater pump-and-treat
systems and wells used to monitor the continued effectiveness of the remedy.
While the walls themselves leave a relatively small footprint and are low maintenance, the
pump-and-treat system will have to be designed carefully for an ecological setting. To avoid
permanent damage to the flora, fauna, and water resources, the project manager should consider
the potential impact of the location of these walls. For example, barrier walls can be placed near
the edge, rather than through, a valuable habitat. Also, to allow for access to a well or wall for
maintenance, it is important to not allow deep rooted vegetation to establish itself near the wall.
Solidification/Stabilization. Solidification and stabilization (S/S) involve modifying the
physical and/or chemical properties of the contaminated material to improve its engineering or
leaching characteristics, or to decrease its toxicity. Solidification encapsulates contaminants into
a solid material of high structural integrity. Stabilization converts waste contaminants into a less
soluble, mobile, or toxic form. S/S can be done either in situ or ex situ. Ex-situ processing
involves (1) excavation to remove the contaminated material from the subsurface, (2) sorting to
remove large pieces of debris, (3) mixing with an S/S agent, and (4) delivering the treated
material to molds or trenches, or for subsurface injection. In-situ processing entails merely
mixing the material with an S/S agent. Some types of waste require solidification or stabilization
prior to being placed into a containment system or covered by an engineered cover system. If ex-
situ S/S is used, the RPM has the choice of returning the treated material to the original
excavation or placing it in another excavation at a different part of the site. The location of this
material may significantly affect the type and amount of habitats that can succeed on the site.
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Permeable Reactive Barrier Walls. Permeable reactive barrier (PRBs) walls are used to
treat contaminated groundwater. Reactive material is placed in the subsurface in the path of the
plume. As the groundwater flows through the material, contaminants are destroyed or made
insoluble, and treated water flows out the other side of the barrier. Compliance monitoring wells
are usually installed downgradient from PRBs to ensure they are meeting cleanup goals. They
may also have performance monitoring wells placed within them to evaluate changes in physical
and chemical characteristics over time. To allow for these sampling activities and the potential
need to replace or repair the reactive materials, access to the wall and monitoring wells is
required until the cleanup is complete.
Phytoremediation. Phytoremediation is an emerging group of technologies that uses the
natural processes of plants to remediate or stabilize hazardous materials in soil, sediment, sludge,
and groundwater in situ. This technology makes use of plant biochemistry to contain, degrade,
destroy, or remove contaminants. Phytoremediation is a broad term that refers to several physical
and biological processes. Phytoremediation treatment systems can be an integral part of the
ecosystem only under very specific conditions. For example, phytoextraction and rhizofiltration
involve the uptake and capture of contaminants (mainly metals and radionuclides) by roots,
limbs, and leaves. Unless these plants are harvested, they may become an attractive hazard to
some species, since the contaminants can become bioavailable to herbivores. Harvesting of plant
materials typically will result in habitats of low or impaired ecological function. On the other
hand, phytodegradation and rhizodegradation, such as occur with poplars and trichloroethylene
(TCE), minimize the bioavailability of the contaminant and eventually transport it through the
plant into the atmosphere where it has a short half-life. Thus, not all of the phytoremediation
processes are appropriate for ecological reuse.
Phytoremediation has been undertaken on a demonstration- or full-scale basis at more than 200
sites nationwide (EPA, 2001g). Although the use of this technology, which was first tested
actively at waste sites in the early 1990s, has been growing, it is still limited to a minority of
sites. It is most effective for sites that have relatively low concentrations of contaminants at
shallow depths over a large area. Plant
species, which are selected on a site-by-site
basis, can include hybrid poplars, willow,
and cottonwood trees; grasses, such as rye,
Bermuda, sorghum, and fescue; legumes,
such as clover, alfalfa, and cowpeas; aquatic
and wetland plants, such as water hyacinth,
reed, bullrush, and parrot feather; and
hyperaccumulators for metals, such as alpine
penny cress for zinc or alyssum for nickel.
Phytoremediation, where it is viable, offers
several advantages. It does not require
excavation of soil and its application may
require only minimum materials handling. In
some cases, the technology can destroy most
At the Aberdeen Proving Ground Superfund
site in Aberdeen, Maryland, hybrid poplar
trees were planted on a one-acre area to
remediate plumes of chlorinated
hydrocarbons in groundwater. TCE is the
principal contaminant and an examination of
tree tissue shows the metabolic degradation
products of TCE (chloral hydrate, trichloro-
ethanol, and di- and trichloroacetic acid).
There is also evidence of minor transpiration
of the TCE into the atmosphere. Since the
planting, TCE concentrations in the
groundwater downgradient of the trees have
fallen since they were planted.
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or all of the pollutants, and require no or few institutional controls ( ICs). Phytoremediation may
also be used as an interim measure to contain contaminants and begin treatment, while a
permanent remedy is being planned. Phytoremediation systems, which are placed and maintained
using traditional agricultural or landscaping equipment and practices, are typically less
expensive to install and operate than many other remediation alternatives. The plants can be
integrated into natural environments, such as wetlands, forests, and grasslands, and arranged to
be unobtrusive and aesthetically pleasing. Plants used in phytoremediation may also provide
other ecologically beneficial functions, such as riparian buffers which can protect streams from
non-point source pollution, stabilize the stream banks, and provide a wildlife habitat.
There are a number of technical and practical considerations that may limit the viability of
phytoremediation at many sites. It is an emerging technology, and more information from
treatability studies and long-term field applications is needed to support its use at some sites. It is
advisable to consult with technical experts to determine its applicability on a site-by-site basis.
Several EPA publications provide information about the application and limitations of these
processes and sources for technical support (USEPA, 2001g; USEPA, 2003; RTDF, 2004).
3.4 Remedy Planning and Design Issues
A number of factors considered during the application of any cleanup technology can affect the
effectiveness of the remedy and the redevelopment of a property. These factors include
settlement, subsurface gases, utilities, surface vegetation, surface water, and institutional controls
(ICs). By carefully accounting for these factors, site managers can ensure that implementation of
any remedy minimizes potential damage to the future use of the site.
Settlement. Settlement may cause damage to containment systems, alter slopes, cause gullies
to form, and disturb other site features. It is primarily an issue at closed-in-place sites, such as
old landfills. Studies show that municipal landfill sites generally settle from 5 to 20 percent of
the landfill depth over a 15 to 30 year period, and some have settled as much as 30 percent.
Settlement is primarily attributed to consolidation of subsurface materials under the weight of
the materials, and cover system above it, and chemical and biological degradation of subsurface
material. The magnitude, distribution, and rate of settlement are governed by several factors such
as material and soil type, age, density, thickness, manner of placement, and moisture content.
The first step in addressing settlement is to consult with a geotechnical engineer to estimate its
magnitude, distribution, and rate. CERCLA guidance recommends that the remedial design
consider estimates of the rate of settlement (USEPA, 1995c). These estimates can be used to
determine if any special design features are needed for the cover or other remedy components.
The rate and magnitude of settlement may also affect the type of habitats that will be successful
at the site. Regular inspections and repair of settlement damage may require human intrusion
into ecologically sensitive areas. The ecological reuse plan should allow for such access.
Several methods are available to reduce the potential for damage due to settlement. When severe
settlement is expected, the construction or reuse project can be delayed until settlement has
largely ceased. A variation on this approach is to install an interim cover that protects human
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health and the environment or arrange for temporary uses of the area, such as a nurse crop like
annual rye grass, to control erosion and provide green space. Then, when settlement is
essentially complete, the interim cover could be replaced or incorporated into the final cover.
Several construction techniques, such as accelerating the consolidation of the subsurface
materials through various forms of preloading, vibrocompaction, and dynamic compaction are
available to allow acceleration of remedy construction. Although these techniques are primarily
used at sites designated for commercial or recreational reuse, they may be useful at some
ecological reuse sites. These approaches, however, will not sufficiently affect settlement caused
by biodegradation.
Managing Gases. Depending on the waste composition, some containment sites, primarily but
not exclusively landfills, have the potential to generate gas. If not properly controlled, gas could
damage the cover system, infiltrate buildings, provide fuel for fire or explosion, stress
vegetation, and pose other health or safety hazards. In planning for reuse, it is important to
determine the ability of subsurface materials to generate gas and the rate of generation. The
quantity, rate, and type of gas generated at a site are primarily dependent on the composition,
age, and volume of the waste, and moisture conditions. Gases can contain methane, carbon
monoxide, nitrogen, sulfur, volatile organic compounds, and other compounds (USEPA, 1991c).
Control systems can be developed to minimize any adverse affects on the planned vegetation and
wildlife. Gas collection systems can be built into the containment system and gas protection
incorporated into structures placed on or near the containment system. Examples of gas
protection techniques for buildings are provided in the EPA report Reusing Cleaned Up
Superfund Sites: Commercial Use Where Waste is Left On Site (USEPA, 2002). Gas collection
systems can include subsurface piping, and wells and vents that extend through the cover system
to discharge gases to the atmosphere or a treatment system. These components can be placed
where they will not interfere with planned uses, minimize noise, odors, and other disamenities,
and where they are less likely to be accessible to potential trespassers, vandals, or wildlife.
Utilities. Some sites being used for ecological purposes may need to contain underground or
above ground utilities, such sanitary sewers, water, telecommunications, natural gas, and
electricity. Utilities can impact the effectiveness of the containment system in the following
ways:
A utility line can become a conduit for gas migration.
A utility structure that penetrates the cover system can serve as a conduit for water
infiltration into the waste.
If the utility is located within or below the cover system, repair or upgrade work would also
require excavation into the cover and contaminated material.
If the utility is located within or below the cover system, liquids leaked from a sewer or
water lines can increase the quantity of leachate generated. Leakage from a sanitary sewer
located above a cover's hydraulic barrier layer might cause excessive bio-fouling of
drainage media.
Differential settlement of the waste can result in damage to the utility.
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Should utilities be included on the site, special provisions will likely be needed to ensure that
they do not hinder the effectiveness of the remedy or ecosystem functions. For example, burying
a utility line in a protective cap or placing it in an area to contain woody trees should generally
be avoided. A number of other approaches are enumerated in an EPA report Reusing Cleaned Up
Superfund Sites: Commercial Use Where Waste is Left On Site (USEPA, 2002).
Surface Vegetation. Vegetation is usually important to both the operation of the cover system
and to the structure, function, and aesthetics of the post-cleanup ecosystem. The vegetation used
on the cover system can serve several purposes, including limiting soil erosion, promoting
evapotranspiration and surface water management and, in some cases, phytoremediation.
The type of vegetation that will thrive at a site depends on the local climate, soil, and native
plants and animals, and types of containment system. It is usually preferable to use mixtures of
native plant species, since they are acclimated to the area, usually grow well and, once
established, require little or no irrigation, fertilization, or other maintenance. Executive Order
13112 promotes the use of native species for federally funded projects that involve revegetation
and landscaping.3 The selection of vegetation should also consider potential unintended
consequences of some species. For example, deep-rooted plants, such as some trees and shrubs,
typically have not been used on cover systems because of the potential that roots would damage
the cover or grow into the contaminated material. However, if properly accounted for in the
design, a containment system can support a variety of vegetation including woody species. Such
species may require modifications to ensure the
integrity of the cover, such as thicker soil layers,
biota barriers, and drainage features. Some plant
species may attract wildlife species that are
particularly sensitive to the pollutants or that
may overpopulate an area.
Construction activities can also significantly
affect vegetation. Excavations and the
placement of staging areas, access roads, and
treatment systems can be conducted so that they
minimize disturbance to existing plant life and
allow for the planting of additional vegetation.
Surface Water Management. Surface water
run on and runoff can erode the top layer of a
cover system, percolate into a cap, and impact
nearby vegetation, streams, lakes, and wildlife
migration routes. To manage surface water on
cover systems, engineers typically grade the cap
to establish an effective slope (usually 3-5
3 Chapter6, Terrestrial Ecosystems and Superfund Remediations, provides more detail on selecting grass seeds
and other plants for the revegetation of disturbed areas.
Channel for draining surface water away from
containment areas at the Cherokee, Kansas site
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percent), and/or build drainage channels and swales to prevent runon and direct the path of
runoff. Surface water controls also typically include provisions for periodic inspections of flat
areas to detect pooling of water.
Another key design consideration is the impact of the containment system on area hydrology.
Protective caps designed to prevent precipitation from infiltrating into the subsurface can cause
additional surface water run off from the containment area. Run-off controls and water
diversions implemented as part of a remedy can influence water tables and the rate of flow into
streams or wetlands. Depending on the site, reduced flows can result in water losses to adjacent
wetlands. Increased flows can magnify flooding, and cause sedimentation in wetlands and
streams.
Measures to reduce adverse impacts on site hydrology include routing runoff through settling
basins to collect sediment, and constructing runoff controls to reduce the volume and rate of
runoff to low-lying areas, wetlands, or streams. Where possible, diversions can be designed to
minimize changes to natural drainage patterns or the quantity of surface water flows to wetlands
or streams (USEPA, 1993b). Similar considerations may be necessary to mitigate the impacts of
temporary disruptions to the ecology created by remedy construction.
Other Design Considerations. In addition to utilities discussed above, some ecological
reuse sites will contain structures needed for maintenance, restrooms, utilities, or other purposes
and paved surfaces such as parking lots and roads. For the most part, structures in ecological
reuse areas are small and light. If a structure is to be placed over an area containing hazardous
materials, several considerations become important. Differential settlement can cause structural
damage. Gases from subsurface materials can penetrate a building and present health hazards for
building occupants, and a structure can alter surface water flow and habitat migration patterns.
Additional detail on the placement of structures on containment areas can be found in the EPA
report on commercial reuse of Superfund sites (USEPA, 2002).
3.5 Minimizing Ecological Damage During Remedy Construction
Remedial actions that include excavation of soil and wastes often require earthmoving
equipment and large staging areas. Because construction activities often disrupt the surface area
of a site, they can cause considerable loss of existing habitat. Surface disruptions can create
conditions conducive to erosion and sedimentation as well as colonization by undesirable
invasive and exotic plant species. These disruptions may also affect groundwater and nearby
surface waters. Although the depth of excavation differs from site to site, excavation usually
removes the productive layer of topsoil, which contains seeds, roots, and organic material,
essentially sterilizing the site. Site managers could take steps to minimize excavation and other
surface disruptions, avoid erosion and sedimentation, and protect the existing flora and fauna. A
number of considerations for ensuring that construction activities minimize adverse ecological
impacts and contribute to the protection or creation of habitats are discussed below (USEPA,
1993b; NRC, 1992; Kent, 1994).
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Design a Site-Wide Work Zone and Traffic Plan. Construction staging areas, work zones,
and traffic patterns should be delineated to minimize unnecessary disruption of sensitive areas
and existing habitat on or near a site. Areas not requiring surface disruption and areas off-limits
to disturbance, such as steep slopes, sensitive habitats, and clean stream corridors, should be
clearly delineated with fences, tape, or signs to avoid disturbance by site workers and equipment.
At the Rocky Mountain Arsenal, project managers recognized that remediation-related traffic
and road building could have major impacts on the existing habitat at the 27-square-mile site. To
facilitate reuse of the site as a wildlife refuge, they developed a site-wide traffic plan that routed
traffic around valuable habitat and sensitive
areas, minimized the potential for erosion
and sedimentation, and used existing roads
wherever possible.
Minimize Excavation and Retain
Existing Vegetation. Earthmoving can
destroy the roots of trees and other plants as
well as disturb vegetation in uncontaminated
areas. These activities can be restricted to
areas essential for remedy construction and
avoided in all other areas. Some areas with
low contamination levels or immobile
contaminants may be better off if left
undisturbed, if the disruptive impacts of
excavation outweighs the benefits of further
cleanup, especially in valuable habitats
(USEPA, 1997a).
RPMs at the Rocky Mountain Arsenal site,
after conferring with USFWS biologists, left areas within the drip line of trees bordering
contaminated areas undisturbed. At the Myers Property Superfund site in Hunterdon County,
New Jersey, RPMs are saving existing trees above a certain size in areas with low levels of
contamination by hand digging around the roots to a level of six inches. Excavated soil will be
replaced with clean topsoil from off site. The site will be monitored in case large trees fall and
expose soils deeper than six inches.
Phase Site Work. Sometimes construction can be phased so that one area of the site can be
stabilized before another is disturbed. In addition to limiting the amount of disturbed area at any
one time, this approach may also reduce the total soil erosion for the entire site. It also allows for
revegetation or redevelopment of some areas as soon as they are cleaned up, while remedial
construction is proceeding in other areas. The construction can be scheduled to minimize the
area of soil exposed during periods of heavy or frequent rains. Project managers at the Rocky
Mountain Arsenal site, suspended remedial activities during certain seasons to avoid disturbing
the nesting and breeding of sensitive species, such as the bald eagle.
Common Measures to Minimize Damage to
Vegetation During Excavation:
Confine road building, grading, and other
activities that require earthmoving to areas
essential for remedy construction.
Protect existing vegetation from construction
activities with fencing, tree armoring, or
retaining walls. Route construction traffic to
avoid existing vegetation.
Avoid disturbing vegetation on steep slopes
or other sensitive areas where revegetation
tends to be difficult.
Create buffer zones of existing or additional
plants to help control erosion and other
impacts from surface disruption.
In some cases, hand digging may be
warranted around especially valuable,
mature trees.
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Protect On-Site Fauna. In some cases, on-site fauna are temporarily relocated during site
remediation. Relocation may require humane trapping and release, but can also be accomplished
through less disruptive techniques. To relocate beavers and alligators at the French Limited site
in Harris County, Texas, for example, project managers reduced their food supply in areas to be
treated and increased the food supply in other suitable areas of the site.
Locate and Manage Waste and Soil Piles to Minimize Erosion. Waste or soil piles may
be created to temporarily store contaminated soil for treatment or to store treated soil that will be
re-deposited. To minimize disruption of the local habitat, stockpiles should be structured to
minimize runoff, located away from steep slopes, wetlands, streams, or other sensitive areas, and
covered or stabilized to control erosion and dust.
Reuse Indigenous Materials Whenever
Practical. Reusing logs, rocks, brush, or other
materials found on site can provide logistic, cost,
and ecological advantages. Topsoil from on-site
sources is usually well suited for supporting
native vegetation. Treated soil and other materials
can also be used as backfill, thereby reducing the
need for borrow areas. At Loring Air Force Base,
in Northeastern Maine, for example, boulders and
cobbles from the streambed and nearby trees
larger than 15 centimeters in diameter that were
removed during remediation were later used in
stream reconstruction, after completion of RA.
Reuse of native materi als at Loring significantly reduced both the cost of materials and impacts
from heavy trucks.
Control Erosion and Sedimentation. Erosion and sedimentation control measures are
usually needed to avoid disruption of sensitive areas, even when they are not required by state or
local regulation. These measures can include retaining sediment on site, and managing runoff.
Ensure that Borrow Areas Minimize Habitat Impacts. Borrow sites should be located
and used with ecological reuse objectives in mind. Borrow sites can be located in low-value
areas and designed, contoured, and vegetated to meet aesthetic and habitat considerations. Based
on consultations with the USFWS, project managers at the Rocky Mountain Arsenal designed
borrow sites to establish the future habitat of a planned wildlife refuge.
Avoid Introducing New Sources of Contamination. If not properly managed,
remediation activities can introduce new sources of contamination. Contamination can result
from materials used on site, fugitive dust emissions, and operations of equipment and sanitation
facilities. Materials that can cause contamination include pesticides, herbicides, fertilizers,
petroleum products, treatment agents, and solid wastes. Storage areas should be sheltered from
the elements, lined with plastic sheeting, surrounded by berms, and regularly inspected for
releases. Equipment maintenance should be done in suitable staging areas and adequate
At the Loring Air Force Base site, workers used on
site materials to build a log bank
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sanitation facilities for site workers should be provided and not located near streams, wetlands,
and other sensitive areas.
Prevent the Introduction of Undesirable Species. Non-native plant species can invade
and destroy native species. Barren and disturbed, which are susceptible to colonization by
undesirable plants, should be monitored and undesirable species removed where necessary.
Develop and Communicate Ecology Awareness and Procedures. Contractors and
construction engineers are often not cognizant of sensitive ecological areas nor aware that they
should minimize site disturbance and protect site ecology. A site preservation policy should be
articulated and distributed to everyone involved with on-site activities.
3.6 Operation and Maintenance
Operation and maintenance (O&M) protect the integrity of the remedy and the functioning of the
associated ecosystems after the construction of the remedy is complete. O&M related to the
reuse project is usually the responsibility of Trustees or other stakeholders. The responsibility for
O&M related to the remedy usually falls to the PRPs, federal facility, state, or EPA, depending
on which is the lead agency for the RA. There are four major areas of consideration for a
successful O&M program: planning and designing for future O&M needs; specification of which
remedy components require O&M; monitoring of ecosystems and remedy features; and ICs.
3.6.1 Planning and Designing for Stewardship
Preparation for safeguarding the effectiveness of the remedy should begin as early in the remedy
planning process as possible to allow time for EPA, Trustees, and other stakeholders to
coordinate and plan the specifics of the institutional controls and O&M. O&M measures related
to waste containment and control are generally initiated after the remedy has been constructed
and is determined to be operational and functional (O&F) based on state and federal agreement.
For Fund-lead sites, remedies are considered O&F either one year after construction is complete
or when the remedy is functioning properly and performing as designed, whichever is earlier.
PRPs or federal facilities are responsible for O&M for sites for which they have the cleanup
lead. For a Fund-financed site, the state becomes responsible for O&M, once the site becomes
Operational and Functional. Fund-financed remedies that involve long-term treatment or other
measures to restore groundwater or surface water quality are a special case in which EPA will
fund the costs for the first 10 years, and CERCLA requires that states assume the costs after that
period. Additional information on O&M is available in OSWER Directive 9200.1-37FS, EPA
540-F-01-004, "Operation and Maintenance in the Superfund Program," May 2001.
Regardless of who is responsible for O&M, agreements can be made to have many maintenance
tasks implemented by site owners, a local government agency, Trustees or others. It is sometimes
practical to have the same entity undertake O&M activities relating to the ecosystem. (Although,
an appropriately designed ecosystem may be self-sustaining and require little or no maintenance
after an initial establishment period). For example, at the Silver Bow Creek/Warm Springs Ponds
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Superfund site, many monitoring and maintenance tasks are conducted by a Trustee, the
Montana Department of Fish, Wildlife, and Parks. It is often less costly and more effective to
have a Trustee or other stakeholder perform O&M than to have the PRP do it. Such groups tend
to be very committed to follow through in the long run and have knowledge of local conditions.
At some redeveloped sites, O&M tasks may be split among various parties. Generally, an
agreement can be reached between the state or federal regulatory authorities, developer, PRP,
and Trustees to establish procedures for the critical O&M needs. It is important that the roles and
responsibilities are clearly delineated in enforceable agreements and specified in an O&M plan.
Although O&M activities related to the hazardous waste site may be conducted by a Trustee or
other party, the PRP or state (whether or not it is a Trustee) will always be responsible for
ensuring that the site remains protective of human health and the environment.
3.6.2 O&M of Remedy Components
Typical remedy components requiring long-term O&M include protective covers and liners; gas
management and monitoring systems; water collection, treatment, and monitoring systems; and
permeable reactive barriers. O&M monitoring includes four activities (USEPA, 2001a).
Inspection. Routine inspections of covers and other remedy components should be performed on
a regular basis, with the frequency of inspections dependent on the complexity of the remedial
measures. Non-routine inspections should be performed after unusual events such as earthquakes
or large storms. Typically, inspectors check for pooling water, erosion, settling, burrowing
animals, and dead or dying vegetation (which may be caused by methane), among other items.
Sampling and analysis. Sampling and analysis is often conducted to monitor groundwater and
surface water quality, leachate formation, and gas release concentrations. Sampling and analysis
typically includes the collection and chemical analysis of gas, air, and water samples from wells,
probes, and other means. The frequency of sample collection may vary widely.
Routine maintenance and small repairs. Routine maintenance may consist of simple activities
such as mowing and maintenance of a cover or repair of perimeter fencing. On sites that have
operating treatment plants, routine maintenance may be more complex and may require a full- or
part-time plant operator. Typical activities include operating groundwater and gas treatment
systems and repair of erosion damage and of rainwater collection and diversion systems.
Reporting. O&M reports are typically written and submitted to regulatory authorities after both
routine and non-routine inspections. The reports typically include information on the general
condition of the remedial measures, test results from samples collected, and operational data
from treatment processes (e.g., groundwater extraction rate, gas flow rate).
In addition to the annual and special inspections specified in the O&M plan, EPA conducts an
in-depth review of the remedy at least every five years for any site where the remedial action
results in hazardous substances, pollutants, or contaminants remaining on site above action levels
that would allow for unlimited use and unrestricted exposure. The five-year review consists of an
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analysis of whether the remedy is still protecting human health and the environment, and a list of
additional follow-up actions that need to be performed to ensure continued protectiveness,
including the identity of the parties responsible for those activities. Although these reviews can
be performed by EPA or the lead agency for a site, EPA remains responsible for determining if
the remedy is protective. For additional information concerning five-year reviews, see OSWER
Directive 9200.1-37FS, Comprehensive Five-year Review Guidance (USEPA, 200If).
3.6.3 Monitoring Ecological Risks
A monitoring program should be established as part of the post-construction activities to
evaluate the effectiveness of the remedy in restoring ecological function and reducing ecological
risks (USEPA, 1997a, 1999c). Information from the ecological risk assessments prepared during
the RI can be the starting point for developing the monitoring program. The ecological
evaluations prepared by Trustees and other parties can provide additional information useful for
monitoring the ecosystem's function and health during and after remediation. For example,
periodic monitoring of sediment contamination and benthic communities following the removal
of contaminated sediment in a stream can provide indications of the protectiveness of the remedy
as well as the ecosystem's recovery to a more natural condition. At the Revere Chemical
Company Superfund site in Pennsylvania, groundwater and stream monitoring are used in the
evaluation of the risks of heavy metals getting into the groundwater and migrating off site. The
monitoring program is also expected to help evaluate the recovery of important aquatic species.
At Loring Air Force Base, in Maine, site managers consulted with USFWS to identify useful
indicator species such as dragon fly nymphs, midge flies, dace minnow, and brook trout to
monitor the recovery of the stream system after remedial activities. These species were selected
because they are sensitive to contaminants and are quick to manifest symptoms of exposure.
Monitoring programs can be designed to be compatible with ecological reuse. At the Bowers
Landfill Superfund site in Ohio, a seven-acre wetland was created to protect the landfill cap from
flood damage from the Scioto River. Since the
wetland was expected to experience periodic
flooding, groundwater monitoring wells in the
wetland area could become inaccessible or
experience water intrusion during flooding. To
ensure access and prevent the potential water
intrusion, the wells were fitted with risers and
surrounded with earth mounds. The use of a
portion of the site as a wetland does not
preclude the use of monitoring wells to ensure
that leachate from the landfill does not migrate
to the underlying groundwater.
Monitoring wells were installed in the wetland created
at the Bowers Landfill in Pickaway, Ohio
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3.6.4 Institutional Controls
EPA defines institutional controls (ICs) as non-engineered instruments, such as administrative
and legal controls, that help to minimize the potential for human exposure to contamination and
protect the integrity of a remedy (USEPA, 2000b). ICs are designed to work in two general
ways: by limiting land or resource use, and by providing information that helps modify or guide
human behavior. They may be used for a variety of goals at ecological reuse sites, such as to
restrict public access to parts of a site that are particularly sensitive to erosion, or that contain
sensitive or establishing habitats.
An important key to success is to identify and evaluate as much information as possible about
the needed ICs early in the remedy selection process. "Adding ICs on as an afterthought without
carefully thinking about their objectives, how ICs fit into the overall remedy, and whether the
ICs can be realistically implemented in a reliable and enforceable manner, could jeopardize the
effectiveness of the entire remedy (USEPA, 2000b)." Generally, there are three major
considerations with IC use at ecological reuse sites:
Developing IC Objectives. A useful first step is to think broadly about what the IC is intended
to accomplish and establish clear objectives. Common IC objectives for ecological purposes
involve controlling activities in a particular area that could potentially interfere with sensitive
habitats or the ecosystem balance that support the remedy.
Selecting appropriate IC mechanism(s). ICs can be grouped into four general categories:
(1) governmental controls, such as zoning, building codes, and groundwater use restrictions;
(2) proprietary controls, such as common law easements, covenants, and conservation trusts;
(3) enforcement tools with IC components, such as consent decrees and administrative orders;
and (4) informational devices, such as fishing advisories, deed notices, and state registries of
contaminated properties. Since each of these mechanisms has strengths and weaknesses, it may
be prudent to use them in layers. Layering refers to using different types of ICs at the same time
or in sequence. For example, both a conservation easement for catch and release fishing and a
local health department fishing advisory may be used for the same IC objective. The different
types of ICs and the layering concept is described in an EPA guide (USEPA, 2000b).
Ensuring Durability. The third considerations is how to ensure that the specified controls are
effective and remain in place over the long term. Because the implementation, monitoring, and
enforcement of ICs may be carried out by more than one party, it is important to consider the
capabilities and willingness of local authorities and private sector interests to fully implement,
monitor, and enforce the ICs. For example, at the Silver Bow Creek site in Butte, Montana, the
Montana Department of Fish, Wildlife and Parks enforces a fish consumption prohibition.
Another example is at the Bunker Hill Superfund site in Kellogg Idaho, where the Idaho
legislature amended the Environmental Health Code to give the local jurisdictions the authority
to govern all excavation, building, development, grading, and renovation at the site.
Many factors may influence the design and implementation of ICs, such as state policies,
whether the site is a federal facility or whether other regulatory authorities, such as RCRA, are
involved. A useful EPA guide addresses many of these considerations (USEPA, 2000b).
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Section 4. Wetlands and Superfund Remediation
The need to consider wetlands at a Superfund site may arise for a number of reasons. An existing
wetland may be affected by the site contamination or cleanup activities. Local and regional
planners may have determined that a wetland is a worthwhile use for the land, even if the
property did not previously contain one. A response action, whether directed at a wetland or not,
may still have adverse impacts if the wetland is not part of the planning process.4
Generally, activities related to the cleanup of contaminants or repairing damage to wetlands
resulting from releases of hazardous substances or cleanup activities may be paid for with
Superfund Trust Fund monies. However, efforts to create new wetlands, where none existed
prior to the disturbance, or to undertake extensive efforts to restore a wetland, where other
practical alternatives exist, may be considered "enhancements." As described in Section 1.4.3,
EPA cannot fund, nor require PRPs or others to fund, enhancements of a remedy. Nevertheless,
there may be situations in which extensive restoration efforts are not considered enhancements.
The determination of whether or not an action or facility is considered an enhancement is
determined on a site-by-site basis and involves coordination with Trustees and other parties with
knowledge and interest in local ecologies. Even if EPA does not pay for activities related to the
restoration or creation of a wetland, it may coordinate remedial activities with such efforts.
Developing and implementing cleanups involving wetlands can involve very complex trade-offs.
For example, removing contaminated materials from a wetland may involve excavation of all
vegetation and growing media, effectively destroying all ecosystem function and structure.
Sometimes, less damage is done by leaving the contamination in place and using other
techniques, such as covering or amending soil.
Whether a remediation involves an existing wetland or the creation of a new wetland, the
following steps are typically taken: (a) evaluation of the characteristics, function, and condition
of wetlands related to the site; (b) determination of the type of wetland functions and structure
that would be beneficial in the area after the remediation; (c) development of a wetland design
that will achieve the stated ecological functions; (d) construction of the remedy and wetland
features while ensuring that remediation activities have minimum impacts on existing wetlands
and other ecosystems; and (e) specification and implementation of explicit maintenance
requirements. Although this section is based primarily on experiences from sites where a wetland
ecosystem was the primary reuse goal, these steps would also apply to sites being developed for
commercial or other uses, when these sites also have wetland issues.
Once it has been determined that wetlands are to be affected by a remediation, a number of key
factors that will influence the success of the wetland habitat should be considered. Some of these
factors are discussed below.
4 A wetland outside a site's boundaries may be hydrologically connected through surface water or groundwater.
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4.1 Wetland Regulatory Requirements
Several regulatory requirements generally apply when a remediation or reuse project affect
wetlands. The Clean Water Act (CWA) provides authority for regulating discharges of pollutants
to waters of the United States. Section 404 of the Clean Water Act establishes a program to
regulate the discharge of dredged and fill material into waters of the United States, including
wetlands. Wetlands are defined as "those areas that are inundated or saturated by surface or
groundwater at a frequency and duration sufficient to support, and that under normal
circumstances do support, a prevalence of vegetation typically adapted for life in saturated soil
conditions. Wetlands generally include swamps, marshes, bogs, and similar areas." (40 CFR Part
232.2 (r)). Activities in waters of the United States that are regulated under this program include
fill for development, water resource projects (such as dams and levees), infrastructure
development (such as highways and airports), and conversion of wetlands for other purposes,
such as farming and forestry.
Typically, an actual §404 permit is not required for on-site Superfund response actions, however
any off-site activity affecting wetlands must meet all §404 requirements, including a permit.
Even though §404 permits are not required for on-site Superfund actions, the substantive
guidelines of §404(b)(l), which are environmental criteria that must be satisfied before a §404
permit can be issued. Any off-site activity affecting wetlands must meet all requirements of
§404, including obtaining permits. EPA guidance provides information for considering laws
other than CERCLA and for fostering Agency coordination when carrying out remediations
affecting wetlands at Superfund sites.5 Actions at Superfund sites affecting wetlands must
comply with Executive Order 11990 relating to the protection of wetlands, which directs federal
agencies to avoid the long- and short-term adverse impacts associated with the destruction or
modification of wetlands and avoid direct or indirect support of new construction in wetlands
whenever a practicable alternative exists.6 Thus, unavoidable impacts to wetlands from
CERCLA response actions should be mitigated to comply with pertinent regulations and
executive orders.7
Under §401 of the CWA, states and tribes can review and approve, set conditions for, or deny all
federal permits or licenses (such as those that might be issued under §404) that might result in a
discharge to state or tribal waters, including wetlands. States and tribes make their decisions to
deny, certify, or condition permits or licenses primarily by ensuring the activity will comply with
state water quality standards. In addition, states and tribes look at whether the activity will
5 U.S. EPA, 1994, Office of Solid Waste and Emergency Response, Considering Wetlands at CERCLA Sites, EPA
540/R-94/019. This guidance document also discusses how wetlands should be considered in compliance with
applicable or relevant and appropriate requirements (ARARs) under § 121(d) of CERCLA. It discusses CWA Section
404 as a potential ARAR and mitigation in accordance with the CWA Section 404(b)(1) Guidelines, which were
promulgated as regulations in 40 CFR 230.10, as important environmental criteria to be considered.
6 OSWER Directive 9280.0-02 of August 1985, Policy on Flood Plain and Wetlands Assessments for CERCLA
Actions, states: "Under this policy, Superfund actions must meet the substantive requirements of Executive Order
E.O. 11988 (Floodplain Management), and E.O. 11990 (Protection of Wetlands).
7 Examples of mitigation actions are discussed in U.S. EPA, 1994, Office of Solid Waste and Emergency
Response, Considering Wetlands at CERCLA Sites, EPA 540/R-94/019.
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violate effluent limitations, new source performance standards, toxic pollutants, and other water
resource requirements, including those under watershed and wetland protection programs under
state and tribal law or regulation.
The provisions of other CWA sections and other federal laws and executive orders may also
apply to actions affecting wetlands. For example, §402 mandates the National Pollutant
Discharge Elimination System and §403 addresses Ocean Discharge Criteria. Section 10 of the
Rivers & Harbors Appropriation Act of 1899 establishes a program to regulate activities
affecting navigation in United States waters, including wetlands. The Federal Agriculture
Improvement and Reform Act of 1996, commonly known as the Farm Bill, included
modifications to four programs related to the conservation of wetlands on agricultural land. The
Endangered Species Act provides a program for the conservation of threatened and endangered
plants and animals and the habitats in which they are found. In addition, several executive orders
may also apply to wetland-related projects, including Executive Order 12630 (Government
Actions and Interference with Constitutionally Protected Property Rights, 1988); Executive
Order 12962 (Recreational Fisheries, 1995); and Executive Order 13186 (Responsibilities of
Federal Agencies to Protect Migratory Birds, 2001). EPA directives provide useful information
for coordinating requirements (USEPA, 1990c, 1990d, 1993b, and 1994a).
One approach sometimes employed in restoring or protecting wetlands is the use of "wetland
credits," which are issued by "mitigation banks." A wetlands mitigation bank is a wetland area
that has been restored, created, enhanced, or (in exceptional circumstances) preserved, and is
then set aside to compensate for future conversions of wetlands for development activities
elsewhere. Credits are issued to organizations or individuals that establish or own the bank. They
can be used or sold to third parties who convert wetlands for development elsewhere. A wetland
bank is developed under a formal agreement with a regulatory agency. A benefit of this
arrangement is that in addition to removing contaminants and protecting or restoring a wetland,
an individual land owner or organization can sell credits. Furthermore, if the site is in a state
where conservation areas are not taxed, the land owner can save on property taxes. Use of this
approach requires that an ecologist examine the proposed project and confirm that there are
environmental benefits. Several sources are available for information on mitigation credits and
banking, including an EPA web site, http://www.epa.gov/OWOW/wetlands/facts/factl6.html
and the National Wetland Mitigation Plan, http://www.mitigationactionplan.gov. According to
the National Mitigation Banking Association, there are about 100 banks in the U.S. in almost
three dozen states (NWMBA, 2004). http://www.mitigationbanking.org/
4.2 Wetland Characteristics
A recommended first step in designing a remedy that involves a wetland is to develop a thorough
understanding of the role of the wetland in the overall ecosystem and the relationships between
the various plant and animal species within the wetland. It is also important to determine if any
endangered, sensitive, or commercially important species are present. Understanding the wetland
will help evaluate which wetland functions and structural characteristics to protect, restore, or
create. Similar evaluations should be conducted in anticipation of potentially new wetlands to be
created on or near the site. This evaluation should begin early in the RI/FS stage, because
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information and analyses on the function and condition of the wetlands are important to the
remedy selection and design process.
A wetlands characterization should include, at a minimum, an evaluation of the size, location,
ecological structure, hydrology, soil, vegetation, and function of the wetlands.8 A wetlands
delineation may be conducted to identify the limits of jurisdiction under the CWA Section 404
regulatory program.9 During the RI, it is also important to determine if wetlands on or adjacent
to Superfund sites have become contaminated. The determination of whether the wetlands have
been or will be affected by the contamination is usually made in the ecological risk assessment,
which contributes to the evaluation of remedial alternatives for the site. Assessment of the
impacts of the contamination on wetlands and evaluation of potential wetlands disturbance from
remedial alternatives is generally done as part of the RI/FS.
4.3 Wetland Vegetation and Hydrology
A good wetland design attempts to achieve
ecological function, as defined above.
Usually, after an initial establishment period
following construction, the wetland will
undergo a succession of changes in
vegetation, ultimately achieving a more
Tree planting in wetlands at the Loring Air Force
Base site in Limestone, Maine
Wetland functions may include wildlife and waterfowl habitat, water quality improvement, groundwater recharge
and discharge, flood water storage and conveyance, and shoreline and erosion control.
9 The 1987 U.S. Army Corps of Engineers Wetlands Delineation Manual is the EPA and Corps of Engineers
standard for delineation of wetlands. A wetlands delineation is an on-the-ground determination of the boundary
between wetland and upland using the three criteria of hydrophilic (wetlands) vegetation, hydric (wet) soils, and
hydrology, in the form of flooding or soil saturation.
Analyses of hydrological conditions (e.g., hydroperiod, or the period of time during which a
wetland is inundated with water, and water depth) help define the site's wetland vegetation
associations (a plant community type of definite floristic composition, uniform habitat
conditions, and uniform appearance). Analyses of soil conditions (e.g., field observations
supplemented by soil maps) help define the historic native vegetation associations, the
appropriate wetland species for the site, and any constraints on the wetland posed by soil
characteristics. Generally, reestablishment
of an historic vegetation association tends to
lead to a successful wetland ecosystem. For
sites where the historical native vegetation
association cannot be determined, analyses
of nearby wetlands with soil and hydrology
similar to the project site can help determine
the types of vegetation that are likely to be
successful.
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natural wetland that requires little or no maintenance.10 To achieve a natural wetland vegetation
association, the site will require a reliable natural water supply and the appropriate hydroperiod
and water depth. Where a wetland is designed specifically for waterfowl habitat, artificial water
supply systems (e.g., pumps and gated culverts) may be used. However, these systems will
usually increase maintenance costs and reduce the abili ty of the wetland to sustain itself. These
factors are generally evaluated thoroughly in the design stage.
It is important to consider water availability and soil type when selecting and placing the
vegetation. Wetter vegetation associations (e.g., perennial marshes) can be established on nearly
any soil type. Drier vegetation associations (e.g., seasonal marshes or wet meadows) require
more careful consideration of soil type. Because inundation is less frequent, soil saturation is the
primary source of water. It is also important to consider the successional status of the various
species. Where appropriate, seeded species that can quickly establish may be planted first and
species that are more difficult to establish can be planted later (e.g., rooted wetland plants
salvaged from nearby areas or purchased from nurseries). Where available, a natural seed bank
in existing wetland soils is often adequate for establishing wetland vegetation.
4.4 Wetland Wildlife
Wetlands provide valuable wildlife habitat. The ability of a wildlife species to thrive in a wetland
is dependent upon a number of factors, including the minimum habitat area necessary for the
species, the minimum viable population of the species, the species' tolerance for disturbance,
and the wetland ecosystem's functional relationship to adjacent water resources and ecosystems.
Thus, three factors will play a major role in determining the effectiveness of a wetland for long-
term wildlife use: 1) the size of the wetland, 2) the relationship of the wetland to other wetlands,
and 3) the level and type of disturbance (Kent, 1994; National Research Council, 1992; USEPA,
1994a).
Wetland size is perhaps the most
important factor in designing for wildlife.
Designers should determine which
wildlife species can be supported at a
planned wetland. The area necessary to
support minimum viable populations of
species varies widely among the species.
Few Superfund-related wetland projects
will be large enough to support the
minimum viable populations for many
species. Consequently, a wetland
designed for wildlife use should consider
the connectivi ty of the site, through
habitat corridors, to other habitats. Habitat
corridors that connect smaller wetlands
can provide a mechanism for interpopulation movement, effectively increasing the habitat size
10 Succession refers to the changes in a vegetation association overtime to a more mature phase.
The Northwest 58th Street Landfill in Miami, Florida provides a
vibrant habitat for waterfowl
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and creating a more sustainable population base. Usually, this arrangement also results in a
reduction of the risk of local extinction as a result of localized disturbances. Species can disperse
through the habitat corridors and colonize other areas. Because species have different dispersal
abilities and different habitat tolerances, it is important to evaluate the habitat needs of each of
the anticipated species.11 For migratory birds, the design typically would focus on providing
breeding or wintering habitat, or resting or feeding places within their large migratory corridors.
The effective size of a wildlife habitat area can also be increased by establishing or increasing
upland buffers. In addition to reducing direct disturbances to wetland wildlife from surface
runoff, buffers can help support part of the life requirements for some species. For example,
buffers can provide additional areas for cover and forage.
Wetland wildlife management has historically focused on waterfowl management, especially
game species. More recently, it has increasingly focused on maintaining species diversity.
Management techniques range from simply installing nest boxes, to actively managing a
wetland's hydrology, to enhancing habitat for some species. For example, bird boxes were
installed along the riparian wetlands at the Army Creek Landfill Superfund site, in New Castle
County, Delaware, to encourage nesting.
Wetland protection or creation measures can sometimes have unintended consequences. For
example, efforts to attract wildlife can sometimes cause one species to thrive so well that it
throws the wetlands ecological functions out of balance or interferes with anthropomorphic
activities in the area. For example, an overabundance of Canada geese have consumed too many
wetland plants at a number of wetlands. Sometimes, geese attracted to an area by a wetland also
consume desirable plants at nearby residences and businesses. The later point is especially
important for Superfund sites, many of which are located in or near urban and suburban areas.
Wetland managers in some areas have attempted actions to make the area less hospitable to this
species, such as using plants that are not palatable to geese or installing fences. Such measures
may also have drawbacks. For example, eliminating plants that geese dislike reduces the
biodiversity of the wetland, which could affect its stability.
The nature and condition of the vegetation is likely to affect a wetland's overall wildlife species
composition. It is recommended that remedy and wetland designers and planners consult with
wildlife agencies for assistance in evaluating and selecting the wildlife management goals and
techniques appropriate for a site.
11 For example, large mammals and some resident bird species have greater dispersal abilities and greater
tolerances for movement through different types of habitats. Amphibians, reptiles, some bird species, and small
mammals often have poor dispersal abilities, narrow habitat tolerances, and are more seriously affected by the
distances between habitats and the suitability of the habitats used as corridors.
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4.5 Remedy Design and Construction Involving Wetlands
Wetland reuse can involve restoration of remediated wetlands or creation of new wetlands in
areas that have been contaminated. Restoration involves modifying a disturbed or altered
wetland to provide greater acreage or improved wetland functions (e.g., habitat, flood storage,
water quality improvement). Wetland creation involves building a new wetland where none
currently exists. Unless severely degraded, a natural wetland will usually provide more functions
to the ecosystem than a created wetland because of uncertainties in the successful creation of
new wetlands. While a created wetland may be suitable for some species, such as waterfowl,
other species are usually less likely to colonize them than they are to adapt to restored natural
wetlands.
Consequently, where natural wetlands exist at a Superfund site, it is important to carefully
consider remedial design and construction methods that will avoid or minimize any adverse
wetland impacts. RPMs may need to avoid or limit certain remedial activities to minimize the
extent of wetland disturbance. To ensure that wetland projects are built as designed and to
minimize the potential for adverse impacts from remedy construction, careful coordination
between wetland and remedy designers and construction contractors is important.
Many aspects of remedy and wetland protection, restoration, or creation are site-specific and
designed to address local conditions. Nevertheless, the following techniques are often applicable
and, where appropriate, may be considered in remedy and wetland construction (Kent, 1994;
National Research Council, 1992; USEPA, 1994a).
Wetland Design and Construction Considerations
Use flags or temporary fencing to prevent disturbance of existing on-site habitats.
Carefully manage grading during construction to meet design specifications, since proper
grading is often essential to developing a site hydrology that will support successful wetland
vegetation associations.
Remove invasive exotic plants from a site prior to construction, to the extent possible.
Whenever practicable, salvage existing plants or wetland soil that could provide a seed bank
and use these to reestablish native species.
Where possible, collect plant material from within the immediate region and ensure that it is
also free from disease, insects, and weeds.
When nursery-grown plants are used, select species from local sources that are genetically
similar to native plant species, whenever possible.
Ensure that all seed used in a wetland project is certified, and free of weeds and disease.
Check all water control structures during daily, seasonal, and peak flows for maintenance
needs and to ensure that they are achieving the planned site hydrology.
Remedy Design and Construction Considerations
Consider alternative locations for remedy components to minimize impacts to wetlands.
Consider alternative access routes and staging areas for construction that minimize impacts.
Design the site layout to minimize the area required for construction of the remedy.
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Minimize grading and backfilling, to reduce the potential for sedimentation and minimize
the need for special erosion control measures during construction.
Use sedimentation and erosion controls (e.g., hay bales, siltation fences, geotextile and filter
fabrics) to contain sediment-laden runoff generated by upland construction activities.
Install erosion controls (e.g., geotextiles and filter fabrics) on newly graded slopes in
conjunction with seeding efforts to hold soil in place until the vegetation is established.
Promptly reseed or replant to stabilize newly graded slopes.
Design adequate drainage and minimize the adverse hydrologic impacts of drainage
channels.
Minimize the clearing of trees, ground cover, and other valuable vegetation to maintain
existing vegetative buffers and to reduce runoff from construction areas and erosion.
Minimize land clearing and alteration of existing slopes and grades along shorelines, to
reduce erosion potential and wave impacts.
Minimize compaction of wetland soils by construction equipment (e.g., through the use of
wide, low pressure tires on vehicles to distribute the loads on wetland soils).
Locate staging areas for equipment outside of wetlands and their buffer zones and provide
for adequate systems to control sedimentation from construction equipment, accidental
releases of fuel, oil, and other potentially hazardous materials from equipment.
In wetlands and other sensitive habitats, use pilings where practicable to support foot or
equipment traffic and reduce the impacts from construction equipment.
Schedule construction to avoid impacts to any sensitive or commercially or recreationally
important species present by avoiding peak growing seasons, fish spawning and migration
periods, and peak waterfowl migratory periods.
Schedule construction to minimize the time between the disturbance and revegetation.
4.6 Wetland Maintenance
Many wetlands require monitoring and maintenance to ensure that the habitat is functioning as
planned and that pollution sources are being controlled, especially when the vegetation is being
established. The maintenance of remedy components were discussed in Section 3. This section
addresses activities needed to maintain the function and structure of wetlands. Although
maintenance needs are site-specific, the following are some typical issues to be addressed.
Weed control is important because invasive species can quickly replace native or planned
species. Weed control generally entails identifying and addressing conditions that encourage
the establishment of exotics, removing those that are established, and replacing them with
appropriate plants.12
Disturbed areas are especially vulnerable to aggressive exotic species, such as purple
loosestrife (Lythrum salicaria), water hyacinth (Eichornia crassipes), and salvinia (Salvinia
molestd). It is important to take timely action to control exotics.
12 For example, quick establishment of a dense ground cover or other measures to reduce soil disturbance is often
effective for limiting the spread of exotics. Annual exotics or weeds can be removed manually by pulling the plants or
cutting them above ground. Perennial weeds can be eradicated or reduced through chemical controls. Woody plants
usually can be removed once a year either manually or by cutting and subsequent herbicide application to the stump.
For some drier wetlands vegetation associations, mechanical mowing may be effective.
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Deer, rabbit, or beaver grazing can damage young plants. This problem can be controlled by
installing wire screens around the plants or the planted area to help protect vegetation until
the ecosystem becomes established.
Where opportunistic native species begin to dominate a wetland and crowd out other
species, measures to increase species diversity should be implemented.13
When important plants are lost, wetland areas often must be replanted. Plant losses can
result from unexpected conditions such as erosion from a heavy storm, inadequate root
penetration prior to the storm, and inadequate water supply due to lower than normal
precipitation.
Scouring can be caused by increased flow velocities through the site or reoriented high
velocity flows. To minimize additional scouring apply new erosion controls as soon as
possible after the storm or other events that caused the erosion.
It may be necessary to monitor for insect or disease infestations, and quickly treat them.
Any litter or debris that collects at the site should be removed at least annually.
For sites near populated areas, public education efforts can help reduce maintenance issues
associated with litter or debris dumping, off-road vehicle use, or other human activities that
may threaten the long-term success of a wetland project.
Wetlands that are actively managed will usually require more maintenance for components such
as pumps, culverts, and piping.
4.7 Sources for Technical Assistance on Wetlands
The following are selected sources for technical assistance for wetland reuse. Other sources of
information are provided in the References beginning on page 61.
Society of Wetland Scientists (SWS), publishes Wetlands Journal - http://www.sws.org/wetlands
U.S. Army Corps of Engineers, Waterways Experiment Station. Wetlands Research Program and
Wetlands Research Technology Center, http://www.wes.armv.mil/el/wetlands/wetlands.html
U.S. Department of Agriculture, Natural Resources Conservation Service, Wetland Science
Institute, http://www.pwrc.usgs.gov/wli
U.S. Department of Interior (DOI), U.S. Fish and Wildlife Service. National Wetlands Inventory.
http://www.nwi.fws.gov
U.S. Environmental Protection Agency, Office of Solid Waste and Emergency Response.
Environmental Fact Sheet: Controlling the Impacts of Remediation Activities in or Around
Wetlands. EPA 530-F-93-020, EPA1993.
13 Examples include cattails (Typha spp.) and common reed (Phragmites spp.).
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U.S. Environmental Protection Agency, Office of Solid Waste and Emergency Response..
Considering Wetlands at CERCLA Sites, EPA 540/R-94/019, 1994.
http://www.epa.gov/superfund/resources/remedy/pdf/540r-94019-s.pdf
U.S. Environmental Protection Agency, Office of Water, Office of Wetlands, Oceans and
Watersheds. http://www.epa.gov/OWOW/wetlands
(And River Corridor and Wetland Restoration link- http://www.epa.gov/owow/wetlands/restore/
U.S. Geological Survey (DOI), National Wetlands Research Center - http://www.nwrc.gov
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Section 5. Stream Restoration
and Superfund Remediation
At some Superfund sites, contamination has degraded stream corridors to the point that in-stream
or riparian habitats are biologically dead or dying. Cleaning up this contamination is complicated
by the fact that cleanup remedies can physically disrupt stream habitats. For example, removing
contaminated sediment from streambeds or contaminated soil from streambanks will usually
entail alteration of the channel, and leave the streambanks barren and erodible after cleanup.
Restoring these resources after cleanup can be a major undertaking with no guarantee that a
viable ecosystem will successfully establish as anticipated. Ecosystems are complex and may
take years to reach equilibrium or fully establish. A major natural event such as a flood or heavy
rainfall can seriously damage or destroy vegetation that has not yet fully established. Restoration
must address questions concerning practicality, predictability of outcomes, and overall
effectiveness of specific techniques. Because ecological restoration is an imprecise discipline,
our ability to predict outcomes is limited. For some stream corridors, we cannot be sure that
physical reconstruction of the stream will not do more harm than to eliminate sources of stress
(such as upland point or nonpoint sources of pollution) and allow the stream to recover through
natural processes.
This section provides an overview of considerations for designing and implementing remedies
that facilitate ecological reuse of stream corridors and mitigating adverse ecological impacts of
constructing remedies. A successful stream cleanup, combined with appropriate restoration
strategies can hasten the recovery of degraded stream corridors and begin the natural process of
restoring their ecological functions. Flealthy stream corridors can provide important habitat for
fish populations; erosion and sedimentation control; high-quality water for wildlife, livestock,
flora, and human consumption; opportunities for recreationists to fish, camp, picnic, and enjoy
other activities; and support a diversity of plant and wildlife species.
5.1 Evaluating Stream
Corridor Conditions
Restoration of degraded streams generally
begins with an assessment of the cause of
disturbances and a characterization of the
degradation. These assessments, along with
other information, can help remedial project
managers (RPMs), communities, and other
stakeholders establish remediation and
reuse goals. A useful first step in assessing
a stream system is to collect and analyze
baseline data on existing species, in-stream
Excavating streambed at Loring Air Force Base, Limestone, Maine
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and riparian habitat, soil characteristics, and stream function. Both the remediation and reuse
teams will typically seek to identify and inventory existing animal species and vegetation and
evaluate key ecological stressors to the existing riparian and aquatic life in the stream corridor.
In addition to evaluating site contamination in the RI, other common disturbances to stream
ecology should be evaluated and prioritized. These disturbances can include stream channel
alteration, water quality impairment, invasion by exotic species, loss of riparian vegetation, and
compaction or undercutting of streambanks.
Another important, but often difficult, step is to define the conditions of the stream corridor prior
to the disturbance. Knowledge of the pre-disturbance condition can help evaluate the cause of
the disturbances and to develop a model for reestablishing a viable habitat with similar
ecological processes that thrive overtime. When historical records are unavailable, information
on undisturbed, nearby stream corridors that have physical characteristics similar to that of the
disturbed area can help to depict reference conditions for determining the type of ecosystem that
will likely be successful at the site.
At Loring Air Force Base in Northeastern Maine, RPMs realized that removal of contaminated
wetland and stream soil and sediment would severely disrupt the stream and wetland areas. They
decided to create a thorough record of the pre-remediation conditions of these areas by carefully
mapping stream channels, streambanks, in-stream structures, and wetland areas. For each stream
segment, workers mapped boulders, submerged logs, riffles, pools, water depths, substrate
textures, plant communities, and topography. They photographed the streambed every 30 meters,
entered the exact locations of these photographs onto topographic maps, videotaped the area,
conducted extensive sampling, staked out these locations, and developed maps using Global
Positioning System (GPS) equipment. Project managers used the information to restore plant
communities according to their prevalence prior to the site's disturbance, reconstruct wetland
topography, and restore stream channels and in-stream structures.
5.2 Stream Corridor Restoration Considerations
After characterizing the stream corridor, it is
important to establish detailed reuse goals, and
identify alternative approaches to remediation and
to achieving the ecosystem conditions specified in
the goals. For stream corridors at Superfund sites,
reuse planning can be grouped into four areas:
stream channel restoration, streambank
stabilization, streambank revegetation, and
watershed management.
Stream Channel Restoration. Removal of streambed layout at Loring Air Force Base,
contaminated sediment and soil from stream Limestone, Maine
channels and banks during a remedial action
usually severely disrupts stream flow. In such instances, reconstruction of stream channels and
banks is usually necessary. Decisions about stream channel width, depth, cross-section, slope,
and alignment profoundly affect future hydrology (and the resulting ecology) of the stream
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system. Restoration design typically considers factors such as the physical aspects of the
watershed hydrology, sediment size distribution, average flood flows, and flood frequency.
When designing a stream channel restoration, it is important to try to anticipate the impacts of
future land uses on the watershed. Ideally, the restoration team will have sufficient knowledge of
the types of habitats that will be compatible with the area from the evaluations discussed above.
Streambank Stabilization. Disturbed or reconstructed streambanks often require temporary
stabilization to prevent accelerated erosion. Temporary stabilization may consist of natural
materials such as logs, brush, and rocks and can be designed so as to not hinder permanent
revegetation. In some cases, geotextiles, natural fabrics, and bioengineering techniques (see
below) may be necessary. Revegetating
streambanks using seeding or bare root
planting techniques will often fail if the
stream is subjected to flooding before
vegetation is fully established.
Consequently, temporary vegetation for
stabilizing streambanks may be more
successful using anchored cuttings or pole
plantings (e.g., woody cuttings or poles
inserted and anchored into the
streambank) taken from species that sprout
readily, such as willows.
Streambank Vegetation. Plants play a
crucial role in many stream ecosystems.
They help regulate stream temperature (by
providing shade during hot days and
reducing heat loss during cold nights),
filter upland runoff to remove sediment
and nutrients, stabilize streambanks and
prevent erosion, and provide habitat for
terrestrial and some aquatic species.
Existing native vegetation, especially
mature trees, should be protected wherever
possible during site cleanup and restoration activities. Many sites will require some revegetation.
Species for vegetation should be selected for their ability to establish a long-lasting plant
community rather than as quick fixes for erosion or sedimentation problems. For example, fast
growing non-native species may quickly stabilize a denuded stream bank, but over the long term
they may end up invading the entire stream corridor to the detriment of desirable native species.
As indicated above, there is a wide range of approaches that could be used to restore stream
corridors. Some examples appear in the box on this page. Where possible, stream restoration or
protection should focus on removing disturbances to enable natural processes to restore stream
function over time. Approaches that attempt to establish ecosystems similar to pre-disturbance
conditions tend to have more long-term success and result in less maintenance than more highly
engineered solutions (e.g., gabions or riprap) that reduce the amount of viable habitat. In
Potential Stream Corridor Restoration
Approaches:
Restore the stream channel to pre-disturbance
conditions, improve the soil characteristics of
the streambanks, and enable natural
recolonization of riparian vegetation.
Restore the stream channel, improve soil
characteristics, and plant native riparian
species.
Replant with native species without restoring
the physical characteristics of the stream
corridor.
Plant trees and shrubs adjacent to the stream
channel to help regulate in-stream water
temperatures, improve water quality, and
enhance aquatic habitat.
Establish buffer strips adjacent to streambanks
Allow natural, self recovery of the stream
system.
Ensure that upland areas are not contributing
stressors to the stream.
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addition, approaches that address the entire stream system tend to be more successful than those
that attempt to ameliorate disturbance conditions for a specific species at a site.
Watershed Management. The sources of stress on a stream are not restricted to in-stream
conditions and cleanup and restoration of a stream should consider all sources of stress. The
health and condition of a water body is also affected by the watershed ecosystem. Therefore,
cleanup and restoration may need to address watershed processes that tend to degrade
ecosystems, such as sediment loading from road cuts or construction, increased runoff from
impervious areas created by development, and other point and nonpoint sources of pollution.
Sometimes, effective watershed management may obviate the need for in-stream restoration
approaches.
5.3 Construction Techniques
Some aspects of stream construction, such as earthmoving operations, amending soil, and
revegetation, need especially careful planning. Grading or earthmoving, especially with heavy
equipment, should be monitored carefully to ensure that construction contractors adequately
protect existing resources at the site. When unexpected subsurface conditions are revealed, the
reuse design may need to be modified accordingly. If areas with clean, good quality topsoil will
be disturbed, this topsoil can be stockpiled, and spread out on the surface after final grades are
achieved. Soil amendments, such as mulch, fertilizer, lime, sand, or clay, may be added to
provide optimum growing conditions for the desired plant community. A variety of strategies,
such as transplanting, seeding, and natural recolonization, are available to achieve the desired
post-restoration plant community and the timing of revegetation. Many sources of technical
assistance on implementing a revegetation strategy are available (Section 5.5).
Bioengineering techniques have become an increasingly popular approach to streambank
restoration and maintenance. Bioengineering refers to stabilizing the soil or streambank by
establishing sustainable plant communities. A combination of live or dormant plant materials are
typically installed sometimes in conjunction with other materials such as rocks, logs, brush,
geotextiles, or natural fabrics. Bioengineering techniques can be more labor intensive than
traditional engineering solutions and sometimes take longer to control streambank erosion.
Nevertheless, over the long term, they often have lower maintenance costs and create important
habitat.
Finally, some maintenance work, such as erosion controls, reseeding, and the application of soil
amendments, may be required after evaluating the initial progress of stream corridor recovery.
5.4 Designing for Long-Term Habitat
Allowing natural processes to shape the ecosystem in the stream corridor will generally lead to
self-sustaining, long-term recovery of in-stream, riparian, and upland terrestrial habitats in the
stream corridor. Since this process takes time, providing short-term riparian and upland habitats
may hasten the return of wildlife to the disturbed area. For example, many species of birds and
mammals use trees for breeding, food, or cover. Nest boxes, cavities, or other artificial nest
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structures may provide important riparian and terrestrial habitats while natural habitat structures
recover. Use of bioengineering materials in streambank restoration can create support for
terrestrial habitats that enhance aquatic habitats (e.g., provide cover and temperature control).
In-stream habitat quality is largely a function of flow, channel and in-stream structures, water
quality, and riparian and streambank function. Long-term restoration of in-stream habitat is
usually best achieved by relying on natural processes to shape the streambed. Common types of
engineered habitat structures such as weirs, dikes, randomly placed rocks, riffles and pools, fish
passage structures, and off-channel pools may be used to enhance in-stream habitat during the
short term. They are most effective when installed as a complement to a long-term recovery
strategy.
5.5 Sources of Technical Assistance on Stream Corridors
Selected sources for technical assistance for stream restoration are listed below. Other sources
are provided in the References section, beginning on page 61.
Federal Interagency Stream Corridor Restoration Guide: Stream Corridor Restoration:
Principles, Processes, and Practices (1999) - http://www.usda.gov/stream restoration
Izaak Walton League of America, Save Our Streams Program, A Citizen's Streambank
Restoration Handbook (1995) - 1-800-284-4952
Lortie, John P. S. Svirsky, D.S. Hopkins, Jr., and D.B. Gulick, Stream and Wetland
Restoration-Restoring an High Value Trout Stream following the Removal of Contaminated
Sediments, Proceedings of the Conference, American Society of Civil Engineers, Denver CO,
March 1998.
National Park Service, Disturbed Lands Restoration - http://www2.nature.nps.gov/grd/distland
University of Nebraska-Lincoln, Cooperative Extension, Bioengineering for Hillslope,
Streambank and Lake shore Erosion Control (1996) -
http://vvvvw.ianr.unl.edu/pubs/Soil/gl307.htm
U.S. EPA, Office of Water, Ecological Restoration: A Tool to Manage Stream Quality, EPA
841-F-95-007, November, 1995. http://www.epa.gov/OWOW/NPS/Ecology
U.S. EPA, Office of Solid Waste and Emergency Response. Contaminated Sediment
Remediation Guidance for Hazardous Waste Sites: Peer Review Draft, January 2005.
http://vvvvvv.epa.gov/superfund/resources/sediment/pdfs/cover.pdf
U.S. EPA, Office of Water, Stream Corridor Restoration: Principles, Processes, and Practices.
Web Page, http://vvvvvv.epa.gov/ovvovv/vvetlands/restore
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Section 6. Terrestrial Ecosystems
and Superfund Remediation
Plant and animal life at some Superfund sites have been seriously disturbed by the grading or
earthmoving operations of the remediation or previous industrial activities. Some sites have been
denuded of all vegetation and topsoil. Establishing a plant community that will thrive with a
minimum of maintenance is a critical step in developing a healthy terrestrial ecosystem on these
sites. Permanent plant communities can provide wildlife habitat and reduce flooding and runoff.
Temporary plant communities, such as annual rye grass, may provide erosion control quickly, or
until permanent plant communities can become established. The revegetation strategy for
temporary erosion control during a remediation can be combined with the long-term strategy.
Some restoration activities beyond those needed for the response may be considered
"enhancements" (Section 1.4.3) and EPA may not fund such activities, nor require others to fund
them. Regardless of whether activities related to habitat protection, restoration, or creation are
considered enhancements and are funded by Trustees, communities or other parties, it is EPA's
policy to coordinate its activities with Trustees (USPEA, 1999c).
This section discusses factors to consider when plant communities are to be established in
disturbed areas. It addresses general revegetation principles and factors to consider in the course
of protecting or creating natural meadows and establishing vegetation on semi-arid or arid lands.
6.1 General Revegetation Principles
Prompt vegetation of disturbed areas is an effective way to control erosion and sedimentation.
Vegetation can prevent sediment and pollutants typically associated with sediment (e.g.,
phosphorus and nitrogen) from entering nearby surface waters. Special attention should be given
to steep slopes or areas of disturbed soil near drainages. Some general principles for the
revegetation of disturbed areas are provided below (USEPA, 1993; U.S. Department of
Agriculture, 1997a):
Prepare the soil and the seed bed for the selected species. Soil testing may be required to
evaluate whether the pH, nutrient availability, and organic material content can sustain the
desired plant community. The seed bed should be prepared to ensure proper soil texture for
successful plant establishment. At the Hillsides area of the Bunker Hill Superfund site in
Kellogg, Idaho, soil was amended and modified to control for acidity and provide nutrients
for planting native and non-native species that are now growing into more than a thousand
acres of coniferous forest (See Bunker Hill case history in Appendix A).
Select seed mixtures and plants adapted to the soil, climate, and topography of the site. Plant
varieties and seeds propagated from local populations usually result in higher plant survival
rates and maintain the integrity of the local gene pool. Executive Order 13112 promotes the
use of native species for federally funded projects that involve revegetation and landscaping.
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Avoid the use of non-native, exotic
species. Non-native species, once
established, can out-compete and
displace native species, disrupt
ecological processes, and significantly
degrade entire plant communities. Non-
native species can easily become
established in a disturbed area because
of a lack of competition from native
plants. Some invasive species are very
difficult to eradicate during later
attempts to establish native plants.
Although non-native species have been
used to vegetate disturbed areas in the
past, most ecologists today recommend the use of native species.
Seed during optimum periods for plant establishment. Timing will depend on the schedule
of site operations, local growing conditions, and the species selected. Sometimes, a
temporary variety of grass, such as annual rye, could be used as ground cover until the
planting season for other varieties. Information on seeding techniques and conditions for
individual species is usually available from U.S. Department of Agriculture (USD A) Natural
Resources Conservation Service technical guides, university extension offices, and seed
suppliers.
Fertilize according to site-specific conditions and choose a fertilizer formulation that meets
the growing needs of the selected species. Areas without adequate topsoil usually need
fertilizer for the successful establishment of grass and other plants.
Stabilize the surface to hold seed in place, aid in plant establishment, mitigate rainfall
impacts on seed beds, preserve soil moisture, and control erosion. A variety of soil
stabilization methods, such as mulching with straw, hay, or wood-fiber product, or installing
synthetic matting, may be used. The type and amount of mulch applied varies with site
conditions, the extent of erosion potential, and the materials available. Different kinds of
mulches may also be selected for their ability to improve conditions for germination of the
selected species. For example, some mulches may help adjust the pH of the seed bed (See
Bunker Hill case history in Appendix A).
Protect seeded areas from grazing animals, vehicles, and other disturbances until plants are
well established. Protection can be provided by fencing, clearly marked access roads, animal
repellants, trenches or berms to control run on and run off, and interim surface stabilization
methods such as mulching or matting.
Reseed within the planting season, if possible, to replace damaged vegetation or if the
desired plant density is not achieved.
At Loring Air Force Base, seedlings and
saplings of desirable plant species from low
value areas on the base (e.g., areas beside
barracks and the runway) were transplanted to
areas that were being restored. This strategy is
expected to reduce restoration costs and
result in plants that are hardier because they
are already adapted to the unique conditions of
the site. Tree species were selected based on
an inventory conducted at the beginning of the
project. Appendix A provides additional detail
on this project.
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6.2 Meadows
For this report, a meadow is defined as an expanse of open land that is mainly covered with
grasses, forbs, and legumes.14 Natural grasslands generally have enough moisture to support
these species, but not enough to support trees. Meadows often provide a vital habitat for many
plants and animals. Even relatively small meadows can support hundreds of species of grasses,
sedges, legumes, wildflowers, mammals, insects, and birds. Because of their extensive root
systems, native plant species are generally more effective at reducing flooding and runoff and
stabilizing soil than are cultivated landscaping grasses. A natural meadow can be a self-
sustaining ecosystem, requiring little or no maintenance.
Common cool-season species found in meadows
include smooth bromegrass, redtop bent, timothy,
slender wheatgrass, quackgrass, Canada wildrye,
reedgrasses, and numerous species of sedges,
rushes, and spikerushes. Sedge and rush plant
types tend to dominate wetter meadow sites.
Common warm-season grasses include big
bluestem, prairie cordgrass, indiangrass, and
switchgrass. These species are generally planted
in spring or early summer and produce most of
their annual growth during the hot summer
months. They can be used to create a meadow
with very high wildlife habitat value, especially
for ground-nesting birds and many mammals.
Proper establishment of warm season grasses
generally requires more careful planning than do
cool season grasses such as fescue (USDA,
1997a, 1997b, 1998). The ideal planting time for
warm season grasses depends on the climate {i.e.,
planting zones), soil moisture, and soil
temperature. Generally, planting in April and
May will increase the success of grass
establishment. Because some fertilizer
Establishing meadow at Army Creek Landfill
species is available from the USDA Natural
formulations (especially nitrogen) tend to
encourage weed growth, fertilizers should only
be applied during planting if soil test results
indicate they are necessary. Information on
planting procedures and seeding rates for individual
14 Grasses are characterized by jointed stems, sheathing leaves, flower spikelets and fruit consisting of seed-like
grain. Forbs are herbaceous plants other than grasses and grass-like plants. They usually have solid stems and
broad leaves that are net-veined. The flowers of forbs are often large, colored and showy, but they can also be
smaller and less conspicuous. Legumes are plants that produce edible seeds in pods. Legumes are used for human
food, livestock feed, or as a soil-improving crop.
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At the Rocky Mountain Arsenal in Denver,
Colorado, five major seed mixes were used to
create a plant community that would thrive in the
area soils. Native grasses for covers were
selected based on their ability to provide erosion
control and discourage colonization by burrowing
animals, evapotranspiration rates, and drought
resistance. Appendix A (Case Histories) provides
additional detail on this project.
Resources Conservation Service (USDA,
1997a. 1997b, and 1998). Generally,
planting equipment (e.g., a native grass
drill) is required to ensure good seed to soil
contact. Seed should be certified and
purchased on a pure live seed basis.
Warm season grasses are generally slow to
establish and it may take up to three years
after the initial planting year to develop a
good stand. The soil may need to be worked
before planting to provide a firm, weed-free seed bed that will produce a healthy stand of
grasses. During this period, it is important to control weeds and cool season grasses, because
warm season grass seedlings cannot compete with these plants. The control of weeds and cool
season grasses can begin before seeding using one or more of a number of techniques, such as
the application of herbicides, use of a cover or nurse crop, seeding the native grass into the
stubble of a previous crop, and the planting of a cultivated crop for two years, which will kill the
roots of cool season grasses. The use of a nurse crop, such as oats or annual rye, may also control
erosion.15
After planting, the area should be carefully monitored for weeds and protected from grazing to
allow it to establish. Most weeds are difficult to control after warm season grasses are planted.
For the first few years after seeding, perennial weeds and cool season grasses can be controlled
through herbicides or mowing. Mowing just above the seedling height can prevent weeds from
shading out the seedlings. Eventually, annual weeds will usually be crowded out by the
developing stand of grasses, if the stand achieves good density after the first year.
Once established, grass stands usually do not require fertilizer or irrigation. They may require
periodic efforts, such as controlled burning, mowing, and removal of plant litter, to suppress
woody growth and encourage vigorous new growth. To maximize benefits to wildlife, these
activities may be conducted outside of the primary nesting season, preferably in late winter or
very early spring. To ensure that food and shelter are continually available to wildlife, these
management techniques may be applied to only one-third of the grass stand at a time.
6.3 Semi-Arid and Arid Lands
Establishment of native plant communities in semi-arid or arid areas tends to be naturally slow
because of the low amount, and high variability, of rainfall.16 Disturbance in these dry lands from
the activities that led to the contamination or from construction of the remedy can make plant
establishment even more difficult. Techniques for the establishment of vegetation in semi-arid or
15 Nurse crops are species that germinate quickly to form a protective cover over the soil, but are killed by the
winter temperatures, leaving dead roots that continue to hold the soil until spring when the prairie seeds germinate.
16 Arid areas are those with desert climates where the mean annual precipitation is less than 10 inches. Deserts
with large extremes in temperature and moisture have unique plants that are very difficult to establish.
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arid areas are not as well tested as those for natural meadows. A number of factors should be
considered in establishing vegetation in these areas, including the following.
Soil treatment is important because damage to soil structure and function is a common and
serious problem in degraded semi-arid and arid areas. Soil properties should be examined and
improved if necessary. Arid soil, compacted soil, and nutrient-poor soil may be improved by
adding organic amendments, such as leaf and litter compost, composted manures and biosolids,
and mulch that is certified weed-free. These amendments could help bind recalcitrant organic
compounds and metals and increase the much-needed water holding capacity and fertility. Other
measures to improve soil structure and function include soil surface treatments, such as pitting
and imprinting, to increase soil moisture and gully control to improve plant establishment.
Water availability for plants may be improved by shaping the ground to collect and retain
water. Transplanted seedlings may need limited irrigation to survive. However, too much
irrigation may encourage the establishment of invasive weeds, leave salts at the soil surface that
kill plants, or cause infiltration into subsurface contaminated materials.
Seed selection for arid areas is hampered by the limited availability of commercial stocks of dry
land seeds. As discussed in Section 6.1, it is usually better to select seed propagated from local
populations. Because the conditions needed for the growth of these genotypes generally match
those in the area to be planted, they are more likely to successfully establish. If possible, a
commercial seed collector can be hired to collect seed from the local area. Alternatively, seed
can be collected from an area within a 100 mile radius and 500 feet of the altitude of the site to
be planted; where the average rainfall is within two inches per year of the annual rainfall for the
site; and with similar soil characteristics (U.S. Department of Interior, 1995). Seed testing may
be used to ensure high quality, live seed. Proper seed storage will also help maintain the seed's
viability until sowing.
Planting techniques primarily include direct seeding and transplanting. Direct seeding is
generally less expensive. However, in dry areas this technique is more vulnerable to seed loss
from wind, insects, and rodents, as well as declines in germination rates and plant growth as a
result of insufficient rainfall in the months following planting. Container plants for drier areas
are often grown from collected seed. Sufficient time must be allowed for plants to germinate and
achieve the desired growth in a greenhouse or nursery before planting. Using container plants
can be costly and labor intensive. Because plant losses usually occur, it is prudent to budget for
monitoring and replacement.
6.4 Maintenance of Vegetated Areas
After the vegetation is in place, many sites will require periodic maintenance and monitoring to
minimize the invasion of non-native species, eliminate deep-rooted plants that might damage
protective covers, ensure that settlement or erosion does not interfere with the developing
ecosystems or the effectiveness of the remedy, and to observe the meadow's ability to provide
food, shelter, resting and nesting areas for wildlife. For the first few years after seeding,
perennial weeds and cool season grasses may be controlled with herbicides or mowing.
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At the Army Creek Landfill Superfund site in Delaware, the maintenance plan for the vegetated
protective cap provides for mowing at certain times of the year and in particular patterns to
provide food and shelter for birds and terrestrial animals. The site is mowed once a year before
the nesting season for residential birds. Also, the site is mowed in alternating years in vertical or
horizontal grids that leave straight stands of protective vegetative cover for terrestrial animals.
6.5 Sources of Technical Assistance
Selected sources for technical assistance for revegetation are listed below. Other sources are
provided in the References, beginning on page 61.
Federal Interagency Committee for the Management of Noxious and Exotic Weeds, Invasive
Plants, Changing the Landscape of America: Fact Book (1998) -
http://bluegoose.arw.r9.fws.gov/FICMNEWFiles/FactBook.html
North Carolina Cooperative Extension Service, Leaflet No: 645, "Weed Management for
Wildflowers" - http://vvvvvv.ces.ncsu.edu/depts/hort/hil/hil-645.html
Plant Conservation Alliance - http://www.nps.gov/plants
U.S. Department of Agriculture, Natural Resources Conservation Service, PLANTS Database -
http://plants.usda.gov
U.S. Department of Agriculture, Natural Resources Conservation Service, Plant Materials
Program - http://piant-materials.nrcs.usda.gov
U.S. Department of Interior, National Park Service, Denver Service Center, Desert Restoration
Task Force, A Beginner's Guide to Desert Restoration -
http://vvvvvv.serg.sdsu.edu/SERG/B.Guide/Pages/b guide.html
Weed Science Society of America - http://ext.agn.uiuc.edu/vvssa
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References
Finding EPA Publications: Visit http://www.epa.gov/epahome/publications.htm for options on how to
obtain EPA publications. Superfund publications available online are located at
http: //www. ep a. gov/superfond/pubs. htm.
General Remediation Approaches and Guidance
Evanko, C.R. and D.A. Dzombak. 1997. Remediation of Metals-Contaminated Soils and Groundwater.
Groundwater Remediation Technologies Analysis Center, Carnegie Mellon University.
Mahmood, A. 1998. Site Investigation, Remediation, and Closure: A Simplified Guide for Environmental and
Real Estate Professionals. Rockville, MD: Government Institutes, Inc.
RTDF, 2004. Remedial Technologies Development Forum, web site containing information relating to
phytoremediation with an emphasis on organics. http://www.rtdf.org/public/phyto/default.htm
U.S. EPA, 1985a. Covers for Uncontrolled Hazardous Waste Sites, EPA 540/2-85/002.
U.S. EPA, 1985b. Settlement and Cover Subsidence of Hazardous Waste Landfills, EPA 600/2-85/035.
U.S. EPA, 1986. Critical Review and Summary of Leachate and Gas Production from Landfills, EPA
600/2-86/073.
U.S. EPA, 1987a. Engineering Guidance for the Design, Construction, and Maintenance of Cover Systems for
Hazardous Waste, EPA 600/2-87/039.
U.S. EPA, 1987b. Prediction/Mitigation of Subsidence Damage to Hazardous Waste Landfill Covers, EPA
600/2-87/025.
U.S. EPA, 1990a. Basics of Pump and Treat Remediation Technology, EPA 600/8-90/003.
U.S. EPA, 1990b. Air Emissions from Municipal Solid Waste Landfills - Background Information for
Proposed Standards and Guidelines, EPA 450/3-90-01 la.
U. S. EPA, 1990c. CERCLA Compliance With Other Laws Manual, Parts I and II, OSWER Directives
9234.1-01 and 9234.1-02.
U. S. EPA, 1990d. CERCLA Compliance With CWA and SDWA, pub. 9234.2-06/FS, February, 1990.
U. S. EPA, 1991a. Conducting Remedial Investigations/Feasibility Studies for CERCLA Municipal Landfill
Sites, EPA 540/P-91/001.
U.S. EPA. 1991b. Handbook: Ground Water, Volume II: Methodology, EPA 625/6-90/016b.
U.S. EPA, 1991c. Design and Construction of RCRA/CERCLA Final Covers, EPA 625/4-91/025.
References
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U.S. EPA, 199Id. Compilation of Information on Alternative Barriers for Liner and Cover Systems, EPA
600/2-91/002.
U.S. EPA, 1991e. Ecological Assessment of Superfund Sites: An Overview. ECO Update. Volume 1, Number
2, Publication 9345.0-051, Office of Solid Waste and Emergency Response.
U.S. EPA, 1992. Engineering Bulletin: Sluny Walls, EPA 540/S-92/008.
U.S. EPA, 1993a. Compilation of Ground-Water Models, EPA 600/R-93/118.
U.S. EPA, 1993b. Environmental Fact Sheet: Controlling the Impacts of Remediation Activities in or Around
Wetlands. EPA 530-F-93-020, Office of Solid Waste and Emergency Response.
U.S. EPA, 1993c. Presumptive Remedy for CERCLA Municipal Landfill Sites, OSWER-9355.0-49FS, EPA
540-F-93-035, Office of Solid Waste and Emergency Response.
U.S. EPA, 1994a. Considering Wetlands at CERCLA Sites, EPA 540/R-94/019, Office of Solid Waste and
Emergency Response, http://www.epa.gov/superfund/resources/remedy/pdf/540r-94019-s.pdf
U. S. EPA, 1994b. Remediation Technologies Screening Matrix and Reference Guide, Second Edition. Federal
Remediation Technology Roundtable. EPA/542/B-94/013, NTIS PB95-104782.
U.S. EPA, 1995a. Ground Water and Leachate Treatment Systems, EPA/625/R-94/005.
U.S. EPA, 1995b. Land Use in the CERCLA Remedy Selection Process, OSWER Directive 9355.7-04.
U.S. EPA, 1995c. Report of 1995 Workshop on Geosynthetic Clay Liners, EPA 600/R-96/149.
U.S. EPA, 1995d. Presumptive Remedies: CERCLA Landfill Caps RI/FS Data Collection Guide, EPA
540/F-95/009. http://www.epa.gov/superfund/resources/presump/finalpdf/caps.pdf.
U.S. EPA, 1995e. Ecological Restoration: A Tool to Manage Stream Quality, EPA 841-F-95-007, November,
1995. http://www.epa.gov/OWOW/NPS/Ecology
U. S. EPA, 1996a. Presumptive Response Strategy and Ex-Situ Treatment Technologies for Contaminated
Ground Water at CERCLA Sites, OSWER 9283.1-12, EPA 540/R-96/023.
U. S. EPA, 1996b. Pump and Treat Groundwater Remediation, EPA 625/R-95/005.
U.S. EPA, 1997a. Ecological Risk Assessment Guidance for Superfund: Process for Designing and
Conducting Ecological Risk Assessments, EPA 540-R-97-006, OSWER 9285.7-25, June 1997.
http://cfpub.epa.gov/ncea/cfm/recordisplay.cfm?deid=12460
U.S. EPA, 1997b. Ground Water Issue: Design Guidelines for Conventional Pump-and-Treat Systems, EPA
540/S-97/504.
U.S. EPA, 1997c. Rules of Thumb for Superfund Remedy Selection, EPA 540-R-97-013.
http://www.epa.gov/superfund/resources/rules/rulesthm.pdf
References
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U.S. EPA, 1997d. CERCLA Coordination with Natural Resource Trustees, OSWER Directive Number
9200.4-22A. http://www.epa.gov/superfund/programs/nrd/fields.pdf
U.S. EPA, 1998a. Permeable Reactive Barrier Technologies for Contaminant Remediation,
EPA 600/R-98/125.
U.S. EPA, 1998b. Guidelines for Ecological Risk Assessment, EPA/630/R-95/002F, April 1998.
http://cfpub.epa.gov/ncea/cfm/recordisplay.cfm?deid=12460
U. S. EPA, 1999a. Ground Water Issue: Fundamentals of Soil Science as Applicable to Management of
Hazardous Wastes, EPA 540/S-98/500.
U. S. EPA, 1999b. Reuse of CERCLA Landfill and Containment Sites, EPA 540-F-99-15.
http://www.epa.gov/superfund/resources/presump/finalpdf/reuse.pdf
U.S. EPA, 1999c. Issuance of Final Guidance: Ecological Risk Assessment and Risk Management Principles
for Superfund Sites, Directive 9285.7-28 October, OSWER.
http://www.epa.gov/oswer/riskassessment/ecorisk/pdf/final99.pdf
U.S. EPA, 1999d. Treatment Technologies for Site Cleanup: Annual Status Report (Ninth Edition), EPA 542-
R99-001, Office of Solid Waste and Emergency Response.
U.S. EPA, 2000a. Reusing Superfund Sites, EPA 540/K-00/00.
http://www.epa.gov/superfund/programs/recycle/sribroch.pdf
U.S. EPA, 2000b. Institutional Controls: A Site Manager's Guide to Identifying, Evaluating and Selecting
Institutional Controls at Superfund and RCRA Corrective Action Cleanups, EPA 540-F-00-005.
http://www.epa.gov/superfund/resources/institut/guide.pdf
U.S. EPA, 2000c. Introduction to Phytoremediation, EPA/600/R-99/107, National Risk Management
Laboratory, Office of Research and Development, Cincinnati, Ohio, February 2000.
U.S. EPA, 2001a. Operation and Maintenance in the Superfund Program, OSWER 9200.1-37FS, EPA 540-F-
01-004. May 2001.
U.S. EPA, 2001b. Reuse Assessments: A Tool to Implement the Superfund Land Use Directive, OSWER
Directive No. 9355.7-06P. June 2001. http://www.epa.gov/superfund/resources/reusefinal.pdf
U.S. EPA, 2001c. Reusing Cleaned Up Superfund Sites: Recreational Use of Land Above Hazardous Waste
Containment Areas, EPA 540/K-01/002. http://www.epa.gov/superfund/programs/recycle/pdf/recreuse.pdf
U.S. EPA, 200Id. Reusing Cleaned Up Superfund Sites: Commercial Use Where Waste is Left on Site, EPA
540/K-01/008. http://www.epa.gov/superfund/programs/recycle/c_reuse.pdf
U.S. EPA, 2001e. Superfund Post Construction Completion: An Overview, EPA/540/F/01/009.
http://www.epa.gov/superfund/action/postconstruction/pcc_overview.pdf
U.S. EPA, 2001f. Comprehensive Five-year Review Guidance, EPA 540-R-01-007.
http://www.epa.gov/superfund/resources/5year/index.htm
U.S. EPA, 2001g. Brownfields Technology Primer: Selecting and Using Phytoremediation for Site Cleanup,
EPA 542-R-01-006, Office of Solid Waste and Emergency Response, July, 2001.
References
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Volume II Methodology. U.S. Army Corps of Engineers Waterways Experiment Station, Vicksburg, MS.
Berger, J.J. (ed.), 1990. Environmental Restoration: Science and Strategies for Restoring the Earth.
Washington, DC: Island Press.
Cairns, J., Jr. (ed.), 1994. Rehabilitating Damaged Ecosystems. 2nd ed. Boca Raton, FL: CRC Press.
Clemants, Stephen, 2002. Is Biodiversity Sustainable in the New York Metropolitan Area? University Seminar
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FWS/OBS-79/31. Washington, DC: U.S. Fish and Wildlife Service.
Cronk, Q.C.B. and J.L. Fuller, 1995. Plant Invaders: The Threat to Natural Systems. New York: Chapman &
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America, Inc., Save Our Streams Program. January 1995.
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Extension, Institute of Agriculture and Natural Resources, University of Nebraska-Lincoln. G96-1307-A.
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for Erosion Control. New York: John Wiley and Sons, Inc.
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Changes, http://aggie-horticulture.tamu.edu/extension/ornamentals/protect/protect.html.
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Kentula, M.E., et al., 1992. Wetlands. An Approach to Improving Decision Making in Wetland Restoration
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Kusler, J.A. and M.E. Kentula (eds.), 1990. Wetland Creation and Restoration: The Status of the Science.
Washington, DC: Island Press.
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Lortie, John P., S. Svirsky, D.S. Hopkins, Jr., and D.B. Gulick, 1998. Stream and Wetland Restoration.
Reprinted from Engineering Approaches to Ecosystem Restoration: Proceedings of the Conference, American
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Mitsch, W.J. and J.G. Gosselink, 1993. Wetlands. 2nd ed. New York: Van Nostrand Reinhold.
Mitsch, W.J. and S.E. Jorgensen, 2004. Ecological Engineering and Ecosystem Restoration, John Wiley &
Sons, HobokenNJ. 411pp.
NMBA, 2004. National Mitigation Banking Association, web site, http://www.mitigationbanking.org/
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Payne, N.F., 1992. Techniques for Wildlife Habitat Management of Wetlands. New York: McGraw-Hill.
Robinson, G.R. and S.N. Handel, 1993. Forest Restoration on a Closed Landfill: Rapid Addition of New
Species by Bird Dispersion, Conservation Biology, 7: 271-278.
Rosgen, D., 1996. Applied River Morphology, Pagosa Springs, CO: Wildland Hydrology Books.
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U.S. Department of Agriculture, No date. Native Grass Seed Availability, Purchasing Strategies and Handling
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U.S. Department of Energy, 1997. Preferred Alternatives Matrices Remediation/Waste Processing, Office of
Environmental Restoration.
U. S. Department of Interior, 1995. A Beginner's Guide to Desert Restoration, National Park Service, Desert
Restoration Task Force, Denver Service Center.
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www2.nature.nps.gov/grd/distland/watersheds.htm
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Publication 9345.0-051, Office of Solid Waste and Emergency Response.
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Waters, EPA 840-B-92-002, Office of Water.
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References
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Appendix A
Ecological Reuse Case Studies
This Appendix describes five projects where successful ecological reuse has occurred on
remediated waste sites where contaminated material or waste treatment systems remain on site.
Although these projects represent a wide range of sites, pollution problems, and ecological
resources, they are not exhaustive of all circumstances that occur at Superfund sites.
Nevertheless, they demonstrate how remediation and reuse efforts may complement each other.
The discussion for each site includes a brief description of the site and contamination, key
factors considered during remediation that were important to the planned ecological reuse, the
reuse plan and results, and lessons learned. The cases are listed below.
Silver Bow Creek/Warm Spring Ponds, Butte, Montana: Wetland and riparian areas
were remediated and restored to provide a habitat for more than 230 types of resident or
migratory waterfowl, birds of prey, brown and rainbow trout, and terrestrial wildlife. The
site is also used for low-impact recreational activities, such as catch and release fishing and
hiking.
Bowers Landfill, Pickaway County, Ohio: A seven-acre wetland was developed in a pit
created when clay was dug up for the landfill cap. The wetland functions as a buffer to
protect the landfill from flooding and prevent damage to the cap.
Cherokee County Galena Subsite, Cherokee County, Kansas: Native prairie grasses
were used to stabilize the clean soil that was placed over mine tailings. The tall, wavy grass
stands have encouraged the return of wildlife and now harbor birds and small mammals.
Army Creek Landfill, New Castle County, Delaware: Grains, wildflowers, and other
carefully selected vegetation were planted to attract migratory birds for resting, nesting, and
feeding. In addition to the habitat for birds and wildlife, wetlands were also restored.
Bunker Hill Mining and Metallurgical Site, Kellogg, Idaho: Three different types of
ecosystems were restored at the second largest Superfund site in the country. A grassy
riparian floodway is home to frogs, deer, birds, and other wildlife on approximately 200-
acres along a I-V2 mile stretch of a river. A 1,000-acre hillside area was revegetated with
native and non-native species to reduce the amount of sediment entering surface waters and
provide a healthy wildlife habitat for elk and other native species, which are now returning
to the area. A 27-acre wetland was planted with native grasses, and waterfowl and otters
have returned to the site.
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A.1 Silver Bow Creek/Warm Spring Ponds, Butte, Montana
Site Background: This site
includes three settling ponds
covering approximately 2,500
acres, three wildlife ponds, and
nearby streams and wetlands. The
ponds are within the flood plain of
Silver Bow Creek, just above the
headwaters of the Clark Fork
River. The site became
contaminated between the late
1800s and 1980 as a result of
mining wastes deposited haphazardly into and adjacent to streams, wetlands, and dry land in the
vicinity. The streams carried an astounding 19 million tons of tailings and other mining wastes
into the headwaters of the Clark Fork River, where they were the principle cause of fish kills.
To reduce the harmful effect of the tailings on the Clark Fork River, the Anaconda Copper
Company dug three settling ponds, now called Warm Springs Ponds. Beginning in 1967, lime
was added to the ponds to increase the system's ability to precipitate out metals. Although these
ponds helped reduce some of the adverse impacts of the mining wastes on the Clark Fork River,
they eventually accumulated millions of cubic yards of metals-contaminated tailings, soil, and
sediment. Concerns were also raised about the risk that a severe flood or earthquake could cause
a catastrophic failure of pond berms, and result in the release of millions of cubic yards of
tailings and sediment into the river. As a result of the contamination, EPA placed the site on its
list of hazardous waste sites needing cleanup (National Priorities List) in 1983.
Despite the environmental problems, Warm Spring Ponds provided a major nesting and resting
area for abundant waterfowl in the Upper Clark Fork River basin. Some of the tributaries also
provided a fisheries habitat for species such as brown and rainbow trout. Two threatened and
endangered bird species, the Bald Eagle and Peregrine Falcon, are occasionally seen at the
ponds.
The most prominent Natural Resource Trustees (Trustees) at the site were the Department of
Interior (DOI) (represented by the U.S. Fish and Wildlife Service (USFWS)), the Confederated
Salish and Kootenai Tribes, and the State of Montana. These Trustees are developing plans for
further restoration and improvement of the wetland and riparian habitats with the concurrence of
USFWS, and subject to public review and comment.
Remedy: The remedy, which was built between 1991 and 1995, was designed to reduce
waterborne and windblown migration of contaminants and included the following activities:
About 450,000 cubic yards of tailings and contaminated sediment from the ponds and
nearby areas were removed, the area was capped, and a comprehensive water treatment
system was installed.
Pond area prior to remediation
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About 200,000 cubic yards of tailings and contaminated soil from the Mill-Willow Bypass
(which connects two streams) was excavated, and the bypass channel was restored.
Tailings and contaminated soil were consolidated in the ponds.
The performance of all the ponds was improved by raising and strengthening the berms,
constructing new inlet and hydraulic structures, and upgrading treatment capabilities.
Some portions of the ponds were dry closed and some were wet closed to isolate the metals-
contaminated materials.1
Pond 3 was enlarged to provide the capacity to receive and treat flows as large as those from
a 100-year flood event.
Spillways for routing excess flood water were routed into the bypass channel.
The ponds are used to precipitate heavy metals so that water discharged from Warm Springs
meets ambient water quality guidelines, thereby protecting the trout fishery downstream in the
Clark Fork River. The treatment of water entering the Ponds will be necessary until Silver Bow
Creek upstream of the ponds is cleaned up.
Reuse Plan: Prior to the remediation, the Warm Spring Ponds area provided a major nesting and
resting area for waterfowl, and a habitat for brown and rainbow trout. As a result of the
remediation, the habitat for fish and wildlife has been vastly improved and the site is now being
used for low-impact recreation. Some of the key activities that have allowed these reuses are:
In the course of excavating contaminated materials in the Mill-Willow Bypass, the channel
was reconstructed into a six-mile long meandering stream with diverse features such as
riffles and pools. Plants were selected to stabilize the stream banks, provide cover for
wildlife, and restore indigenous species of riparian vegetation. Part of the floodplain was
relocated there and the area now serves as a flood bypass channel to divert flow in excess of
a 100-year flood event and to protect the pond system and aquatic habitats.
The wet closure of the dry parts of the ponds resulted in the creation of wetland habitat for
resident and migratory waterfowl, as well as the improvement of fish habitat. To improve
the existing habitat, nesting islands were installed around the ponds to protect waterfowl
from predators. The neutratlization of the tailings in these ponds (by chemical fixation) has
resulted in plant growth, forming additional wetland habitat.
Grassland habitat was increased at the site. The capped dry closure areas were recontoured
to control runoff and seeded with native grass species.
Major portions of the site are being used as a wildlife refuge, which is managed by the Montana
Department of Fish, Wildlife, and Parks, as part of the Warm Springs Wildlife Management
Area. Since the mid-1960s, the Department has leased the ponds from ARCO and its predecessor
companies for this purpose, and the institutional controls in the remedy included renewal of this
lease agreement.
The dry closures involved dewatering wet areas and covering them with a protective cap and vegetation. The wet
closures involved flooding of dry portions of tailings areas to stabilize them under water;
Appendix A. Ecological Reuse Case Studies
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Reusing Superfund Sites: Ecological Use Where Waste is Left On Site
Reuse Results: The site now
provides habitat for more than 230
types of resident or migratory
waterfowl, birds of prey, brown
and rainbow trout, and terrestrial
wildlife. The Mill-Willow Bypass
is now a catch and release fishing
area that attracts trout fisherman
from miles around. The Montana
Department of Fish, Wildlife, and
Parks limits fishing to catch and
release with artificial lures, and
the record of decision (ROD)
contains institutional controls that
prohibit taking fish from the site
for consumption.
Other recreational activities available at the site include birdwatching, waterfowl hunting, dog
training, hiking, biking, a self-guided walking tour, and picnicking. Dog training is permitted
during the fall and winter when breeding birds will not be disturbed. The hiking and biking trails
were built on the dikes that separate the ponds. Signs have been posted to prohibit swimming in
the ponds. Further improvements, such as a footbridge, playground, athletic fields, and
additional walking trails and fishing areas, are expected in the future.
Lessons:
If the contaminated material at a site is stable and can be covered with protective materials,
it can remain in the subsurface of a functioning wetland or grassland.
Creative remedy design based on knowledge of the local ecosystem and hydrology can lead
to valuable ecological reuses.
The need to regrade areas disturbed by a remediation can be turned into an opportunity to
consider the establishment or restoration of habitats, such as the riparian habitat along the
bypass.
Some remediation features can serve dual purposes as aids to both habitat restoration and
low-impact recreation. For example, hiking and biking trails can be built on top of berms.
Institutional controls are important to prevent undesirable uses, such as swimming or
consuming fish from potentially contaminated waters. Trustees should be involved in their
implementation.
Restored Pond at Silver Bow Creek
Appendix A. Ecological Reuse Case Studies
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A.2 Bowers Landfill, Pickaway County, Ohio
Site Background: The 12-acre
Bowers Landfill started in 1958 as
a rock quarry but soon became a
dump for municipal waste. From
1963 to 1968, the landfill also
accepted chemical and industrial
wastes. As was common at the
time, the waste was dumped
directly on the ground and simply
covered with soil. When the site
was abandoned in 1968, the debris
and contaminated materials were
left behind. Over the years,
flooding of the nearby Scioto
River caused considerable erosion
damage to the banks leading up
the landfill. Rain and floodwaters
carried chemicals from the landfill into the groundwater under the site and into the river.
Contamination was found in surface water, groundwater, sediment, on-site soil, and off-site soil.
The site is within the Scioto River Hood plain. The area between the landfill and river generally
floods twice a year for nearly 30 days annually. Although this flooding pattern contributed to the
release of contaminants from the landfill, it made the site ideal for creating a wetland. The site's
location in a floodplain and a rural area also facilitated its reuse as a wetland area and wildlife
habitat. Because the wetland was created adjacent to the Scioto River, which is a migration
corridor for waterfowl and shorebirds, there was existing habitat nearby to support ecological
reuse.
Remedy: The remedy involved hauling away some of the materials in the landfill, building a
protective cap over the landfill, and protecting it from the floodwaters. The protective cap was
built of clay taken from elsewhere on the property. To address drainage and erosion concerns a
seven-acre wetland was developed in a pit created when clay was dug up for the landfill cap. The
wetland functions as a buffer to protect the landfill from flooding and prevent damage to the cap.
Measures were also taken to manage the buildup of explosive gas under the cap.
The original ROD called for the installation of riprap in areas of the landfill prone to the
scouring effects of flood waters and the regrading of these areas to allow water to drain away
from the landfill. Wetland creation was not included in the ROD. However, as the remedial
design progressed, recommendations from the Ohio Division of Wildlife and U.S. Fish and
Wildlife Service led to the design and creation of a seven-acre wetland. Although its primary
purpose was to protect the newly-capped landfill from the floodwaters that frequently inundate
the area, the wetland also provides a valuable ecological resource.
Wetlands created at the Bowers Landfill site support provide habitat for
plants and wildlife
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Reusing Superfund Sites: Ecological Use Where Waste is Left On Site
Reuse Plan: The wetland was developed in the seven-acre pit that was created when clay was
dug up for the landfill cap. That area was graded to provide waterways and retention ponds and
seeded to promote growth of wetland plants. Occupying the area between the landfill and river,
the wetland functions as a buffer to protect the landfill from flooding and prevent damage to the
cap. When the Scioto River floods, the wetland holds the flood waters and releases them slowly,
reducing possible damage to the protective cap.
Monitoring wells were installed in the new wetland area to ensure that leachate from the landfill
does not migrate to the underlying groundwater. These wells were fitted with risers and the
surrounding earth was mounded to minimize water intrusion through the wells and to make
access easier during flood periods. Consequently, ecological reuse of the site does not affect the
use of monitoring wells.
Reuse Results: The final remedy took advantage of the location of the landfill to develop a
design that incorporated the creation of a wetland to help protect the landfill's containment
system. The man-made wetland was designed to require minimum maintenance. After seeding,
wetland plants have flourished providing habitat for wildlife and migratory birds.
Lessons:
Newly created wetlands can thrive and provide great benefits to communities and the
environment, if established in an appropriate location.
The need to regrade areas disturbed by remediation can be turned into an opportunity to
establish a wetland, given appropriate hydrological conditions.
Some remediation features can serve as aids to habitat creation and low-impact recreation.
Monitoring programs can be designed to be compatible with wetland reuse. For example, to
ensure that groundwater monitoring wells remain accessible during flood periods, they can
be fitted with risers and surrounded with earth mounds.
Appendix A. Ecological Reuse Case Studies
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Reusing Superfund Sites: Ecological Use Where Waste is Left On Site
A.3 Cherokee County Galena Subsite, Cherokee County, Kansas
Site Background: The Galena subsite is a 25-square mile area that is part of the 115-square mile
Cherokee County Superfund site in southeastern Kansas. The Galena subsite, also known as
Operable Unit 5 (OU5) of the Cherokee County site, had large tracts of mine wastes, water-filled
subsidence craters, open mine shafts, and pits. The Cherokee County site is a former lead and
zinc mining area, which has been divided into six subsites and seven OUs. Over 100 years of
mining produced several million tons of mining wastes, destroyed vegetation and wildlife and
presented potential human health risks. OU 5 addresses the contamination of groundwater and
surface water at the Galena subsite.
The barren countryside was covered with mounds of gray rocks, gravel, and mine waste, and
pockmarked by open mine shafts, pits, and craters filled with murky, contaminated water. Acidic
waters in abandoned mine shafts, runoff from tailings piles, surface waters in mine pits, and
streams draining the site contained significant concentrations of lead, cadmium, and zinc. These
heavy metals have leached into the shallow groundwater. The site is surrounded by homes,
businesses, light industry, farms, and grazing lands. The mining wastes have affected the quality
of the soil, surface water, and groundwater.
Remedy: The remedy included consolidating surface mine wastes in abandoned mine pits, mine
shafts, and subsidence areas on the site, diverting streams away from waste piles, recontouring
of the land surface, and revegetating the area. The wastes were covered with clean soil and
planted with specially selected mixtures of native prairie grasses to control runoff and erosion.
Surface streams were diverted away from the stored contaminants. The land surface was re-
contoured with clean soil and vegetated to control runoff and erosion. Over two million cubic
yards of contaminated mine wastes were relocated and 900 acres of surface mine wastes were
cleaned up.
Reuse Plan: The cleanup work was begun
in 1993, and by 1994 the native prairie
grasses were well on their way to becoming
established. These grasses stabilize the soil
and have encouraged the return of wildlife.
The tall, wavy grass harbors birds and small
mammals. Future uses of the site may
include light industry and grazing. Portions
of the site are likely to remain open space
because future development is limited by
the potential for cave-ins of old mines.
Lessons:
Prairie grasses grown from selected native seed will thrive with little or no maintenance and
serve to protect caps over contaminated materials from erosion and infiltration.
Native grasses can significantly improve the aesthetics of a barren area, thereby improving
the attractiveness of the nearby communities.
Native grasses above containment area at the Cherokee
County site
Appendix A. Ecological Reuse Case Studies
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Reusing Superfund Sites: Ecological Use Where Waste is Left On Site
A.4 Army Creek Landfill, New Castle County, Delaware
Site Background: Army Creek
Landfill is a 47-acre abandoned
sand and gravel quarry that was
used as a landfill from 1960 to
1968 by New Castle County,
Delaware. About two million
cubic yards of municipal and
industrial waste were disposed of
in the landfill. During the rainy
season, the groundwater level
would rise and saturate nearly 30
percent of the waste. In 1971,
after contamination from landfill
leachate was discovered in a
nearby residential well, New Castle County installed a groundwater recovery well system to
control the movement of contaminants toward an aquifer and nearby public water supply wells.
To address contamination in Army Creek, which is adjacent to the landfill, and groundwater
contamination that threatened the local water supply, the site was added to the NPL in 1983.
The site abuts high-quality wetlands to the south and east along Army Creek, which feeds into
the Delaware River. These wetlands, their aquatic life, and other wildlife frequenting the
wetlands were at risk of contamination from hazardous substances such as mercury and
chromium. The creek and Army Creek Pond, a small body of water southeast of the landfill,
were partially degraded by the discharge of contaminated groundwater from the County's
recovery wells.
Remedy: The selected remedy included constructing a multi-layered RCRA type C cover over
the landfill to prevent infiltration of rainwater, continuing the operation of the groundwater
recovery well system to capture contaminated groundwater, and installing an on-site water
treatment facility to treat groundwater before it is discharged into Army Creek and the pond. As
construction of the protective cover began, opportunities for future use of the site as a habitat for
birds and wildlife were investigated and measures to improve wildlife habitat were incorporated
into the design of the cap. Reuse design ideas and other assistance were obtained through
consultations with the USFWS and the Delaware Division of Fish and Wildlife.
Additional constaiction was undertaken to address concerns about flooding in low-lying areas
where treated water feeds into the adjacent Army Creek. The slope and location of discharge
pipes from several existing, on-site sediment basins were modified to create a wetland area. One
of the sediment basins, which was already colonized with native wetland plant species, was left
in its natural state. The second basin was replanted with species typical of riparian wetlands in
the area. The wetlands prevent erosion and flooding, and provide habitat for numerous species of
plants, terrestrial animals, and birds.
Thriving meadow planted at the Army Creek Landfill Sit©
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Reusing Superfund Sites: Ecological Use Where Waste is Left On Site
Reuse Plan: The site's location supports its reuse for wildlife habitat and wetlands. There are
existing ecological resources near the Army Creek, such as high-quality wetlands, and the site is
not located in a densely urbanized or industrialized area. Grains, wildflowers, and other carefully
selected vegetation were planted to attract migratory birds for nesting and feeding. The selected
plants provide the erosion control needed to maintain the integrity of the protective cap as well
as food and habitat for a variety of plants and animals. One of the seeds included in the mixture,
red clover, attracted unwanted burrowing animals and is no longer recommended for use above
containment areas. Bird boxes were installed along the riparian wetlands of Army Creek to
encourage nesting. Gooseberry was planted around the cap's gas vent pipes to provide visual
cover as well as food for animals.
The operation and maintenance (O&M) plan provides for a specific mowing regimen, and
activities to remove undesirable vegetation and burrowing animals. Mowing is done only at
specific times of the year, and in particular patterns, to provide food and shelter for birds and
terrestrial animals. For example, the site is mowed once a year before the nesting season for
residential birds. Also, the site is mowed on alternating years in vertical or horizontal grids that
leave straight stands of protective, vegetative cover for terrestrial animals. Cap integrity is also
maintained through periodic removal of deep rooting, woody plants from the capped area and
humane trapping and relocation of woodchucks, which can burrow into the cap. O&M also
includes activities to minimize the invasion of non-native reed species into the wetland areas.
Wetland restoration was conducted by federal and state natural resource Trustees, which
included the National Oceanic and Atmospheric Administration, USFWS, and State of
Delaware. The funds for this restoration came from payments by the settling parties to offset
injury to wetlands and aquatic life resulting from the previously described releases of hazardous
substances into the creek and pond.
Lessons:
Avoid the use of plants that tend to attract unwanted burrowing animals.
Work closely with Natural Resource Trustees, such as the U.S. Fish and Wildlife Service
and state and local agencies, to develop restoration plans.
Funds for restoration may be derived from settlements for natural resource damages.
Plant appropriate vegetation around permanent features of a remedy, such as gas vent pipes
or monitoring wells, to make them more aesthetic and compatible with the ecosystem.
In developing O&M plans, consider specific needs to remove deep rooting, woody plants
from capped areas; humane trapping and relocation of burrowing animals; and activities to
minimize the invasion of non-native species.
Work with local authorities and Trustees to ensure that cap integrity is maintained over time.
Appendix A. Ecological Reuse Case Studies
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Reusing Superfund Sites: Ecological Use Where Waste is Left On Site
A.5 Bunker Hill Mining and Metallurgical Site, Kellogg, Idaho
Site Background: Bunker Hill, the second largest Superfund site in the country is located in
Northern Idaho and northeastern Washington. Mining operations began in 1886 with lead
smelting starting in 1917. These operations produced refined lead, zinc, cadmium, silver, gold,
and alloys of these heavy metals. Other activities in the area produced sulfuric acid, zinc oxide,
and phosphate fertilizers. Prior to 1938 all liquid and solid residues of mineral processing were
routinely discharged into the Coeur d'Alene River and its tributaries or used for fill. Later, waste
streams were directed to a plain just north of the Bunker Hill industrial complex. Lead smelter
slag was deposited in a pile on the western end of the plain. An impoundment area developed on
the eastern end of the plain was surrounded by a dike of mine tailings and waste rock that over
the years grew to 70 ft in height. All liquid wastes were directed to the pond for settling and then
discharged to the river. In the early 1970s a central treatment plant was constructed at the edge of
the pond to treat water prior to discharge into the river. In 1973, a fire at the smelter damaged the
air emissions controls, dramatically increasing lead emissions at the site. The smelter closed in
1981 and Bunker Hill was placed on the NPL in 1983 (USEPA, Region 10 web site).
This case study addresses three areas
within the Bunker Hill Site that represent
distinct ecosystems: Smelterville Flats - a
riparian floodway; Hillsides - an upland
terrestrial ecosystem; and, West Page
Swamp - a wetlands. These areas had high
concentrations of metals, low pH, low soil
nutrients and organic matter, and/or poor
soil physical properties.
Remedy. For cleanup purposes the site
was divided into three operable units -
OUs 1 and 2 focus on the 21-square mile
area called the Bunker Hill Box. OU 1
includes residential (about 6,000 people)
and other community areas in Shoshone
County and OU 2 includes historic mining
and smelting areas. OU 3, called the
Basin, runs along the Coeur d'Alene
River, through Lake Coeur d'Alene, and into the Spokane River. About 242,000 people live in
the vicinity of the Basin, affecting numerous communities in two states and the lands of the
Coeur d'Alene and Spokane Tribes.
The three areas of ecological reuse in this report are all within OU 2. Due to the bankruptcy of
the major PRP, most of the work in these areas are paid for by the Superfund Trust Fund. EPA
and the State of Idaho are responsible for implementing the remedial action. Each of the three
areas, which are described below, represent the three different ecosystem types addressed in
Chapters 4, 5, and 6 of this report (wetlands, stream corridors, and terrestrial).
WW? >
\ ¦ V'-
Bunker Hill in the Coeur d'Alene River Basin in Idaho is the
second largest Superfund site in the U.S.
Appendix A. Ecological Reuse Case Studies
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Reusing Superfund Sites: Ecological Use Where Waste is Left On Site
Smelterville Flats Remedy and Reuse: The Smelterville Flats cover approximately 200 acres
along a one and one-half mile stretch of the South Fork of the Coeur d' Alene River. During the
almost 100 years of operations at Bunker Hill, much mining waste materials and tailings
discharged upstream into the river were deposited at the Flats. When the river was dammed,
from 1910 to 1932, the Flats served as a tailings pond. The dam failed in 1933 resulting in some
portion of the tailings spreading downstream.
Remedial action called for minimizing direct contact with contaminants, surface erosion, and
migration of contaminants to surface water and groundwater. Tailings were removed from the
floodplain and deposited in the Central Impoundment Area (CIA); portions of the river were
restructured to provide soil barriers; and the flats were revegetated as necessary. The CIA is a
260-acre area constructed over river gravel and jig tailings. Most of the disposal to the area was
discontinued when the mine shut down in 1982. Approximately 1.3 million cubic yards of
tailings were removed. The South Fork of the river was re-routed with the use of small dams and
earth moving equipment to enable the excavation of the tailings
Clean fill was brought in to reshape the river channel, creating more pools, meanders, and
shaded areas. Topsoil was trucked in to revegetate the Flats. One ton per acre of lime and Biosol,
an organic fertilizer, were applied to the soil to help limit toxicity and generally improve soil
conditions. The reconstructed floodplain was revegetated with native grasses. Today the flats are
an established grassy riparian floodway with increased shaded areas and is more hospitable to
plants and wildlife. The U.S. Fish and Wildlife Service conducts bio-monitoring and the State of
Idaho is responsibl e for long-term monitoring of the Flats (USEPA, Region 10 web site; USEPA,
2003; and Macintyre, 1998).
Hillside Remedy and Reuse: The Hillsides within Bunker Hill have been impacted by years of
metal mining and refining and associated activities, such as logging, clearing, and mine waste
rock dumping. These activities, combined with natural events such as forest fires, resulted in an
almost total loss of vegetative cover across much of the hillside area. Construction of terrace
benches disturbed native soils and
introduced over-steepened cut and fill
slopes. The erosion of the
contaminated soils from the hillsides
carried the contaminants to the
streams, gulches and other areas
(USEPA, 2000).
The 1992 ROD called for remedial
action focusing on approximately
3,200 acres of hillside. From the mid-
1990s on, the primary focus has been
on a 1,050-acre almost contiguous
block of land on the southern hillsides
of Bunker Hill. The entire hillside was
highly eroded, acidic, lacking in
moisture and nutrients, and steeply
The revitalized hillsides area of the Bunker Hill Superfund site are
now home to plants and animals, such as this elk.
Appendix A. Ecological Reuse Case Studies
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Reusing Superfund Sites: Ecological Use Where Waste is Left On Site
sloped. The ultimate goal was to return the hillsides to a coniferous forest ecosystem similar to
that found elsewhere in northern Idaho. In addition to the challenges posed by the physical
conditions of the site, restoration was hampered by the limited road access, the cost of shipping
the volume of materials needed, and efforts needed to sustain the seedlings that were planted on
the hillside over the years until they become established (White, et. al., 2003)
Prior to treatment denuded slopes dominated hillsides in Government Gulch. Tree
seedlings, although present, are invisible in this photograph. Coarse woody debris lie
on the slope to the right and toward the foreground (1997).
Post-treatment hillsides environment in Government Gulch (May 2003). a mixture of
biosolids and ash was successful in helping revegetate the area to reduce
sedimentation and provide a healthy wildlife habitat for elk and other native species.
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Reusing Superfund Sites: Ecological Use Where Waste is Left On Site
Demonstration plots were installed in 1997 on some of the steepest portions of the site. Large-
scale revegetation was conducted in 1998, 1999, 2000 and 2001, using helicopters to apply lime
and hydroseed. Soils were amended and modified to control for acidity and provide nutrients.
The plantings included both native and non-native species. The selection of species was based on
their ability to sustain themselves on harsh sites, help stabilize the sediment, and conserve soil
resources. For instance, black locust was planted alongside mountain alder because of its ability
to fix nitrogen. Some species were selected to allow for sunlight to reach seedlings. Hardwood
species of trees were added to areas where conifers had been planted to enhance diversity and
further improve soils. The planting of trees and shrubs was completed in the fall of 2002.
Plant cover is monitored annually after a seeded area is two years old. Surface water is
monitored annually on a continuous basis (White, et. al., 2003). Seventy-three percent of the
acres that had been seeded were found to contain greater than 50 percent cover. This good-to-
excellent cover exists in all watersheds. Studies suggest that the present cover is sustainable.
Surface water hydrology indicates that the revegetation is reducing the amount of sediment
entering the basin from the hillside. Continual monitoring shows that turbidity levels of surface
water discharging from the watershed has dropped significantly following treatment. Native
species, such as elk, deer and coyote, along with native plants such as fireweed, Douglas-fir,
willow, aspen, snowberry, and other species are flourishing the hillsides (USEPA, 2003).
West Page Swamp Remedy and Reuse: West Page Swamp is a 27.2-acre wetland section of the
approximately 170-acre Page Pond area of the Bunker Hill Superfund Site. Page Pond was used
as a disposal area for tailings resulting from mineral mining and processing activities at the
former Page Mill in nearby Humboldt Gulch. The West Page Swamp area was used by the Hayes
Company Mill from 1918 to 1929 for tailings deposits. The water levels and surface areas of the
swamp fluctuate seasonally with high water levels during periods of heavy rainfall and snowmelt
and low levels during dry seasons (USEPA, 2000). The major metal contamination in the swamp
is from lead, zinc, cadmium, and arsenic and, prior to the remediation, the swamp had no
ecosystem functions. Elevated levels of lead in wetlands are the primary ecosystem risk to
migratory fowl that use the wetlands for seasonal feeding and nesting.
The remedy for Page Pond called for (a) the removal of approximately 40-60 thousand cubic
yards of jig tailings from the West Page Swamp area and the placement of this material on the
Page Pond benches as a sub-base for a vegetation cap; (b) evaluation of wetlands associated with
the pond for water quality and habitat considerations, including bio-monitoring; and (c) the use
of hydraulic controls to enhance existing wetlands in West Page Swamp. The objectives of these
remedial actions were to minimize exposure from fugitive dust, minimize releases to surface and
groundwater, minimize habitat destruction, and improve wetland vegetation and habitat.
As part of a closure agreement with U.S. EPA Region 10, the mining companies involved with
the site excavated a 4.9-acre portion of the swamp. In 1997, tailings in this area were removed to
a depth of 0.7 meter to reduce the potential for exposure of wildlife to metal contamination. This
effort was followed in 1998 by a project to test the feasibility of using biosolids compost in
combination with other residuals, like wood ash, to help revegetate the area, reduce the
bioavailability and accessibility of the remaining contaminated materials, and restore ecosystem
function. The biosolid mixtures were delivered with the use of front end loaders and bulldozers.
Appendix A. Ecological Reuse Case Studies
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Reusing Superfund Sites: Ecological Use Where Waste is Left On Site
However, when rising groundwater in the fall caused standing water, access with heavy
equipment became difficult. To gain access, logyard debris was used to build a road over road
fabric. Compost and wood ash were mixed and spread with a thrower from both the newly
constructed road and the county highway. A significant portion of the test area not reached
during initial application was treated in 2000. The wetland was closed on the outlet end in order
to maintain a 2-foot water depth.
St-lijmg
:: : j
Area treated
by spreader
West Page Svuamp|
Upfly
vegetates
Heavily
vegetated
N Straw bales and
| oil boom for filtration
by dozer
sM,
Stfv- I Access road made
with logyard iruastel
I Areas treated
[by blower
At West Page Swamp, EPA used biosolids compost and other materials to accelerate
revegetation and limit the ecosystem impact of metals contamination in wetlands.
Reuse Results:
Today, Smelterville Flats is a vigorous, complex ecosystem composed of extensive wetland and
upland grass/shrub riparian communities. The area is home to frogs, birds, other wildlife, and
plants. The U.S. Fish and Wildlife Service conducts bio-monitoring and the State of Idaho is
responsible for long-term monitoring of the Flats.
A coniferous forest that harbors elk, deer, and other wildlife is now growing on approximately
1,000 acres of hillsides that were severely eroded and acidic. The combination of native
bunchgrasses and forbs and application of appropriately targeted soil amendments have resulted
in slower water movement, invigorated stagnant tree seedlings, and stabilized hillsides with
vegetative coverage.
Native grasses, such as cattails and bulrushes, thrive at West Page Swamp. Waterfowl have
returned and lake otters have moved into the swamp. The area is now a functioning wetland that
is beautiful to view. Water and plant samples are regularly collected to monitor for toxicity.
Monitoring is conducted by the University of Washington, USEPA, and the Idaho Department of
Environmental Quality.
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Reusing Superfund Sites: Ecological Use Where Waste is Left On Site
Lessons:
Biosolid composts and other materials, can be applied to the soil to help limit toxicity,
improve soil conditions, and allow the establishment of valuable riparian ecosystems.
Seriously damaged steep hillsides can be successfully revegetated with native and non-
native species, if the soils can be amended and modified to control acidity and provide
nutrients.
If species that have the ability to sustain themselves on harsh, steep sites are selected, they
can help stabilize the sediment, conserve soil resources, and contribute to restoration or
maintenance of important ecosystems.
The impacts of construction of a remedy can be mitigated by using indigenous materials to
build temporary roads that are designed to either be removed or biodegrade.
In-depth knowledge of a site, collaborative planning, and comprehensive site
characterization can lead to more cost-effective development of viable ecosystems.
If properly managed, contaminated material can be left on site and the site can be restored to
support a variety of ecological or other reuses.
References for Bunker Hill Site
Macintyre, Mark, 1998. Bunker Hill: light at the end of the tunnel, The Seattle Daily Journal,
August 1998. www.dic.com/special/enviro98/10043970.htm
U.S. EPA. 2003. Environmental Protection Agency, Region 10, Hillsides Revegetation Project,
2002 Operational Monitoring Program Annual Report, April 2003.
U.S. EPA. 2000. First 5-Year Review of Non-Populated Area Operable Unit, Bunker Hill
Mining and Metallurgical Complex, Shoshone County, Idaho, September 2000,
www.epa.uov/superfund/sites/fivevear/f00-10003.pdf
U.S. EPA, 2001. Mine Reclamation Using Biosolids, Office of Solid Waste and Emergency
Response, August 2001. http://www.clu-in.oru/download/remed/biosolids.pdf
White, et al., 2003. White, Timothy A. Carmela L. Grandinetti, Stephen D. Miller, Timothy D.
Hill, Dennis L. Mengel, and, Shane M. Waechter, The Bunker Hill Hillsides: A Case Study in
the Use of Adaptive Management in Early Successional Restoration on the Nation's Largest
Superfund Site, presented at the Meeting of the American Society of Mining and Reclamation,
Billings, MT, June 2003.
Web Sites
U.S. EPA. Operable Unit Fact Sheets.
http://www.epa. gov/superfund/accomp/success/bunker ou 12.htm
U.S. EPA, Region 10. Fact sheet and other documents, http://yosemite.epa.gov/rlO/cleanup.nsf
Bunker Hill, Idaho, Ecological Restoration Demonstration,
http://facultv.washinuton.edu/clh/bunker.html
West Page Swamp Wetland Restoration Project, Bunker Hill,
http://faculty.washington.edu/clh/wet.html
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Appendix B. Acronyms
ARARs
Applicable or Relevant and Appropriate Requirements
BRAC
Base Realignment and Closures
BTAG
Biological Technical Assistance Group
CERCLA
Comprehensive Environmental Response, Compensation, and Liability Act
CFR
Code of Federal Regulations
CIA
Central Impoundment Area
CWA
Clean Water Act
EE/CA
Engineering Evaluation/Cost Analysis
EPA
Environmental Protection Agency
GPS
Global Positioning System
MEDEP
Maine Department of Environmental Protection
NCP
National Oil and Hazardous Substances Contingency Plan
NRDA
Natural Resource Damage Assessments
O&M
Operations and Maintenance
OPA
Oil Pollution Act
OSWER
Office of Solid Waste and Emergency Response
OU
Operable Unit
PAHs
Polynuclear Aromatic Hydrocarbons
PCBs
Polychlorinated Biphenyls
PRB
Permeable Reactive Barriers
PRP
Potentially Responsible Party
RCRA
Resource Conservation and Recovery Act of 1976
RI/FS
Remedial Investigation and Feasibility Study
ROD
Record of Decision
RPM
Remedial Project Manager
SARA
Superfund Amendment and Reauthorization Act of 1986
S/S
Solidification/Stabilization
TCE
Trichloroethylene (or Trichloroethene)
USAF
United States Air Force
USD A
United Department of Agriculture
USFWS
United States Fish and Wildlife Service
VOCs
Volatile Organic Compounds
Appendix B. Acronyms
Page B-1
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