OSWER 9472.00-1
vxEPA
United States
Environmental Protection
Agency
Office of Solid Waste
and Emergency Response
Washington DC 20460
October 1984
Solid Waste
Permit Writers'
Guidance Manual
for Hazardous Waste
Land Storage and
Disposal Facilities
Phase I
Criteria for
Location Acceptability and
Existing Applicable Regulations
Final Draft
For Public Comment
U.S. L •;• P; r-tvjlion Agency
R.?g:on Y ' ". ' '
230 Soi.i;-' '-• .- ..'.
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PERMIT WRITERS' GUIDANCE MANUAL
FOR THE LOCATION OF HAZARDOUS WASTE
LAND STORAGE AND DISPOSAL FACILITIES
PHASE I
CRITERIA FOR LOCATION ACCEPTABILITY AND
EXISTING REGULATIONS FOR EVALUATING LOCATIONS
FINAL DRAFT
Office of Solid Waste
Waste Management and Economics Division
U.S. Environmental Protection Agency
401 M Street, S.W.
Washington, D.C. 20460
FEBRUARY 1985
;on Agency
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:c-ncy
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ACKNOWLEDGEMENTS
This manual was prepared by the Waste Management and
Economics Division of the Office of Solid Waste. The
principal editor was Glen Galen. Other EPA personnel
providing major contributions were Arthur Day and Louise Wise.
Consultants played major roles in the preparation of the
guidance manual. Dr. William Doucette of Radian Corporation
developed the major technical sections of the manual and
provided technical assistance and background information in
formulating the manual. Dr. Keros Cartwright of the Illinois
Geological Survey provided thoughtful comment on the approach
to location evaluation. Diane Heineman of GCA Corporation--
Technology Division compiled peer-review comments on the draft
version of the manual and provided technical support. Back-
ground information on weak and unstable soils was assembled by
J.B. McCutchan and K.T. Ajmera of Radian Corporation.
Special thanks is expressed to the personnel of EPA
Regional Offices in Regions I, III, IV, V, VI, and IX for
technical assistance and support in preparation of case study
background information.
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EXECUTIVE SUMMARY
The "Permit Writers' Guidance Manual for the Location of
Hazardous Waste Land Storage and Disposal Facilities has three
purposes: (1) to provide guidance in defining acceptable physical
locations for hazardous waste land storage and disposal (HWLSD)
units, (2) to cite available regulations and statutes and
how these should be applied in evaluating the acceptability of
locations, and (3) to present an outline summary of future Agency
efforts to ensure both proper site analysis and safe location of
such facilities. The intended audience is EPA Regional Office
staff and authorized State Agency personnel who evaluate permit
applications under the authority of the Resource Conservation
and Recovery Act (RCRA).
This Phase I manual provides guidance concerning the physical
location of hazardous waste surface impoundments, waste piles,
and landfills. Location guidance for land treatment units will
be provided in a future document. Part of a broad program to
encourage safe and proper siting of hazardous waste facilities,
this manual is the first of a five document series. Other documents
include:
a. a review of State siting criteria for hazardous
waste treatment, storage, and disposal facilities,
b. a Phase II document describing technical methods for
evaluating locations and determining ground-water
vulnerability,
c. an appendix to the Phase II document containing case
studies, and
ES-1
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d. a permit writers' guidance manual for land treatment
site selection.
Section 2 .0 of this guidance manual describes five criteria
for determining location acceptability. The five criteria are
as follows:
a. Site Characterization - The inherent geologic, hydro-
logic, and pedologic features of the site can be fully
characterized.
b. High Hazard and Unstable Terrains - The site provides
a stable foundation for the engineered containment
structure, is not subject to likely events, either
natural or man-induced, that would damage engineered
containment structures, and does not require active,
ongoing maintenance of engineered containment structures
due to instability or high hazard and unstable terrain
conditions following closure. Sensitive areas that
should be evaluated against this criterion are:
0 flood-prone areas,
0 seismic impact zones,
0 volcanic impact zones,
0 landslide-susceptible areas,
0 subsidence-prone areas, and
0 weak and unstable soils.
c. Ability to Monitor at Location - All potential ground-
water flow paths can be monitored or the facility is
located in a zero recharge zone.
d. Protected Lands - The facility complies with statutes
and rules for Federally protected lands. Protected
lands include:
0 archaeological and historic places,
0 endangered and threatened species and critical habitat,
0 parks, monuments, and scenic rivers/
° wilderness areas,
0 coastal areas,
0 wildlife refuges,
0 significant agricultural lands, and
0 wetlands.
e. Ground-Water Vulnerability - The facility is not
in a vulnerable setting above Class I or II ground
water as defined in the Agency's Ground-Water
Protection Strategy.
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Currently, 40 CFR Part 264 permit standards specify design
and operating requirements for hazardous waste facilities and
establish ground-water monitoring and corrective action
requirements. While Part 264 does not contain explicit location
standards based on hydrogeologic considerations, the ground-water
monitoring and corrective action regulations and the design and
operating requirements contain performance standards that implicitly
involve hydrologic and geologic factors. Current regulations do
not provide the legal basis to deny a RCRA permit at some sensitive
locations. For example, there is no legal basis for permit denial
at a location that satisfies all criteria except the ground-water
vulnerability criterion. Section 3.0 presents existing regulations
that permit writers should apply when evaluating permit applications
against location issues. These regulations may provide a basis
for denying permits to owner/operators for facilities at certain
locations that do not satisfy one or more of the first four
criteria cited above. Except with respect to the ground-water
vulnerability criterion, this manual describes a number of locations
that are particularly sensitive areas where the criteria for
location acceptability are less likely to be met. At these
locations, permit writers must examine whether a facility can be
designed, constructed, operated, and maintained to comply with
existing regulations. Table ES-1 provides a matrix of existing
RCRA regulations related to the first four criteria for location
acceptability that should be evaluated in these sensitive
locations.
ES-3
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The Agency's current regulations do not provide a clear
basis for denying all permits to owner/operators of facilities
that are located in a vulnerable hydrogeology as defined in the
vulnerable ground-water criterion. The Agency's Ground-Water
Protection Strategy, however, presents a framework for implementing
a number of regulatory decisions that are related to ground-water
quality issues. The strategy guides decision-making under
existing regulations, and indicates where regulations will be
amended or created in order to fully implement the policies. Of
particular importance to the RCRA program is the classification
of ground water into three classes and the accompanying division
of certain classes into vulnerable and non-vulnerable hydrogeologic
settings. In addition, recent statutory amendments under RCRA
require that certain facility design and operation provisions
are based on whether the facility is in an area of ground-water
vulnerability.
The Phase II guidance manual will present a definition of
ground-water vulnerability and analytical methods for use in
applying the definition to individual facilities. This definition
and the accompanying methods are being developed in cooperation
with the EPA Office of Ground-Water Protection (OGWP) which is
characterizing vulnerability within a larger context. Additional
guidance on the definition of the three ground-water classes will
be provided by the OGWP at the same time. The Agency will then
develop amendments to the RCRA Part 264 ground-water protection
standards to provide a regulatory basis for applying a ground-water
ES-4
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vulnerability criterion in permitting RCRA hazardous waste management
facilities. Other regulatory amendments will also be made to
fully implement the other provisions of the Ground-Water Protection
Strategy. This Phase I guidance manual discusses ground-water
vulnerability only to the extent necessary to illustrate how the
concept will be ultimately applied after the appropriate amendments
are made to the permitting standards.
All applications for Part 264 permits must be evaluated
against certain existing performance standards and application
information requirements that implicitly involve facility loca-
tion issues. Permit writers may determine after analysis that
the applicant has not demonstrated that the facility will
satisfy one or more of the following:
a. monitoring requirements (Part 264.92 and 264.97)
b. liner foundation requirements (Parts 264.221(a),
264.251(a), and 264.301(a))f
c. the closure standards (Parts 264.111, 264.228(a),
and 264.310(a)),
d. dike integrity requirement (Part 264.221(d)).
An inability to satisfy these standards is grounds for permit
denial.
Location factors may also be relevant to other decisions
made under the Part 264 permitting program. In certain cases,
supplemental provisions under Part 264 can be attached to the
permit based on certain location concerns. Decisions regarding
these supplemental provisions are discussed in various sections
of this guidance manual and referenced in Table ES-2. These may
include the following decisions:
ES-5
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a. whether to grant Alternate Concentration Limits (ACLs)
in the facility's ground-water protection standard
or to exclude Appendix VIII constituents from monitoring
under Section 264.93,
b. whether to require a contingent corrective action program,
and
c. extending the post-closure period.
In addition, the permit writer may have grounds for permit
denial if the applicant is not in compliance with certain other
Federal Statutes designed to protect scenic rivers, wetlands,
archaeological sites, and other Federally protected resources.
Table ES-3 provides a summary of applicable Federal statutes and
Rules that form the basis of the fourth criterion for location
acceptability. Under Part 270.14(b)(20), the permit applicant
may be required to submit additional documentation to show that
the location at which his or her facility is sited is in compli-
ance with other "protected" land statutes. Section 2 .0 of this
manual provides permit writers with guidance in determining
whether a RCRA permit application is consistent with these other
applicable Federal Statutes. Permit writers should more routinely
seek to coordinate with the appropriate Federal Agency for assist-
ance in determining facility compliance with other Federal
statutes.
The Imminent Hazard Provision under Section 7003 of RCRA gives
the Agency broad authority to issue administrative orders where the
presence of solid waste or hazardous waste may present an imminent
and substantial endangerment to health or the environment. Section
3.4 of this Manual presents guidance on the applicability of Section
7003 Administrative Orders that supplements existing Agency guidance,
ES-6
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Section 4 .0 provides the permit writer with site case study
summaries based on actual RCRA permit applications submitted to
various EPA Regional Offices. The case studies are used to
illustrate how the location criteria presented in this manual
should be applied when evaluating RCRA permit applications.
Recommended responses that the permit writer should make regard-
ing various locational issues are also included. These summaries
and additional case studies currently being evaluated will be
presented in more detail in a case study appendix to the Phase
II permit writers' guidance manual.
Section 5.0 of this manual outlines the current Agency
program for developing and implementing RCRA location guidance
and regulations under 40 CFR Part 264. A brief description of
subsequent guidance materials is presented.
The Phase I Location Guidance Manual was developed prior to
the passage of the Hazardous and Solid Waste Amendments of 1984
and is not the "location guidance" called for by the amendments.
That location guidance will be forthcoming and will be clearly
identified as guidance that fulfills the requirements of the
RCRA amendments.
ES-7
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TABLE OF CONTENTS
Paqe
Executive Summary ES-1
1.0 Introduction 1-1
1.1 Scope of Document 1-3
1.2 Related Location Guidance Documents 1-4
2.0 Criteria for an Acceptable Location 2-1
2.1 Site Characterization 2-6
2.1.1 Geologically-Complex Locations 2-7
2.2 High Hazard and Unstable Terrains 2-9
2.2.1 Flood-Prone Areas 2-12
2.2.1.1 Areas Protected by Flood 2-14
Control Structures
2.2.1.2 Coastal High Hazard Areas 2-15
2.2.1.3 Channel Encroachment Areas 2-17
2.2.1.4 Wetlands 2-18
2.2.2 Seismic Impact Zones 2-19
2.2.3 Volcanic Impact Zones 2-21
2.2.4 Landslide - Susceptible Areas 2-24
2.2.5 Subsidence - Prone Areas 2-27
2.2.5.1 Fluid Withdrawal Zones 2-29
2.2.5.2 Karst Terrain 2-32
2.2.5.3 Mine Subsidence Areas 2-33
2.2.6 Weak and Unstable Soils 2-34
2.2.6.1 Organic Soils 2-35
2.2.6.2 Expansive Soils 2-36
2.2.6.3 Liquefaction Sands 2-36
2.2.6.4 Soft Clays 2-37
2.2.6.5 Sensitive Clays 2-37
2.2.6.6 Loess 2-38
2.2.6.7 Quick Conditions 2-38
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Page
2.3 Ability to Monitor at the Location 2-39
2.3.1 Zero Recharge Zones 2-42
2.4 Protected Lands 2-45
2.4.1 Archaeological and Historic Places 2-48
2.4.2 Endangered and Threatened Species 2-49
2.4.3 Parks, Monuments, and Scenic Rivers 2-50
2.4.4 Wilderness Areas 2-51
2.4.5 Coastal Areas 2-51
2.4.6 Wildlife Refuges 2-51
2.4.7 Significant Agricultural Lands 2-52
2.4.8 Wetlands 2-53
2.4.9 State and Local Considerations 2-56
2.5 Ground-Water Vulnerability 2-57
2.5.1 Class I Ground Water 2-60
2.5.2 Class II Ground Water 2-61
2.5.3 Class III Ground Water 2-63
3.0 Existing Regulations to Evaluate Locations 3-1
3.1 Existing RCRA Location Standards 3-1
3.1.1 Seismic Standard 3-1
3.1.2 Floodplain Standard 3-5
3.1.2.1 Wetland Executive Order 3-8
3.2 Existing RCRA Design and Operating Standards 3-9
3.2.1 Monitoring Requirements 3-9
3.2.2 Liner Foundation Requirements 3-13
3.2.3 Closure Standards 3-15
3.2.4 Dike Integrity Standard 3-17
3.3 Supplemental Regulatory Provisions 3-19
3.3.1 Alternate Concentration Limit (ACL) 3-19
and Appendix VIII Exclusion Restrictions
3.3.2 Combined Ground-Water Protection 3-23
Programs in RCRA Permits
3.3.3 Extended Post-Closure Care Period 3-25
3.4 Considerations Under the Imminent Hazard 3-27
Provision of RCRA and Other Provisions of
the RCRA Amendments of 1984
3.4.1 Considerations Prior to Permit Issuance 3-28
3.4.2 Considerations After Permit Issuance 3-30
11
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Page
4.0 Case Studies for Analyzing Location Criteria and 4-1
Existing Applicable Regulations
4.1 Case Study A 4-7
4.1.1 Summary of Locational Evaluation 4-8
4.1.2 Discussion of Location Issues 4-9
4.2 Case Study B 4-14
4.2.1 Summary of Locational Evaluation 4-20
4.2.2 Discussion of Location Issues 4-21
4.3 Case Study C 4-21
4.3.1 Summary of Locational Evaluation 4-30
4.3.2 Discussion of Location Issues 4-31
4.4 Case Study D 4-31
4.4.1 Summary of Locational Evaluation 4-41
4.4.2 Discussion of Location Issues 4-41
4.5 Case Study References 4-42
5.0 Future Agency Efforts 5-1
6.0 References 6-1
111
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TABLE ES-1
TABLE ES-2
TABLE ES-3
TABLE 2.4-1
TABLE 2.5-1
TABLE 3.0-1
TABLE 3.3-1
TABLE 4.0-1
TABLE 4.0-2
TABLE 5.0-1
TABLES
Cross-Reference of Location Criteria and
Existing RCRA Standards for Evaluating
Locations
Supplemental RCRA Provisions Useful as a
Basis for Permitting
Protected Land Statues and Regulations
Protected Land Statues and Regulations
Ground-Water Classification Matrix - Current
RCRA Obligations Based on EPA Ground-Water
Protection Strategy
Cross-Reference of Location Criteria and
Existing RCRA Standards for Evaluating
Locations
Supplemental RCRA Provisions Useful as a
Basis for Permitting
List of Case Study Locations and Locational
Settings
Matrix of Case Studies Versus Relevant
Location Acceptance Criteria
Program Plan for RCRA Guidance and
Regulations
Page
ES-8
ES-9
ES-10
S-47
2-59
3-2
3-20
4-5
4-6
5-3
FIGURE 2.2.2-1
FIGURE 2.2.3-1
FIGURE 2.2.4-1
FIGURES
Seismic Zoning in the United States
Volcanic Impact Zones of the Forty
Eight Conterminous United States
Relative Potential of Different Parts
of the Conterminous United States to
Landsliding
FIGURE 2.2.5.1-1 Fluid Withdrawal Ground Failure Areas
FIGURE 4.0-1
FIGURE 4.0-2
Physiographic Regions of the United
States and Canada
Ground-Water Regions of the United States
2-22
2-25
2-28
2-31
4-3
4-4
IV
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FIGURE
FIGURE
FIGURE
FIGURE
FIGURE
FIGURE
FIGURE
FIGURE
FIGURE
FIGURE
FIGURE
FIGURE
FIGURE
FIGURE
FIGURE
FIGURE
FIGURE
FIGURE
FIGURE
FIGURE
FIGURE
FIGURE
FIGURE
4.1-1
4.1-2
4.1-3
4.1-4
4.2-1
4.2-2
4.2-3
4.2-4
4.2-5
4.3-1
4.3-2
4.3-3
4.3.4
4.3-5
4.3-6
4.4-1
4.4-2
4.4-3
4.4-4
4.4-5
4.4-6
4.4-7
4.4-8
Case Study A:
Case Study A:
Case Study A:
Case Study A:
Case Study B:
Case Study B:
Case Study B:
Case Study B:
Case Study B:
Case Study C:
Case Study C:
Case Study C:
Case Study C:
Case Study C:
Case Study C:
Case Study D:
Case Study D:
Case Study D:
Case Study D:
Case Study D:
Case Study D:
Case Study D:
Case Study D:
Site Plan
Location of Cross Sections
Sections I-I1 and II-II1
Sections Ill-Ill1 and IV-IV
Topographic Map
Borings and Well Map
Section A-A1
Section B-B"
Section C-C'
Topographic Map
Location of Cross Sections
Section A-A1
Section B-B1
Section C-C1
Section D-D1
Soil Boring Location Map
Monitoring Well Network
Section A-A1
Section B-B1
Section C-C1
Section D-D1
Section E-E1
Section F-F1
Page
4-10
4-11
4.12
4-13
4-15
4-16
4-17
4-18
4-19
4-24
4-25
4-26
4-27
4-28
4-29
4-33
4-34
4-35
4-36
4-37
4-38
4-39
4-40
v
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1.0 INTRODUCTION
The physical location of HWLSD facilities directly
influences the potential for impacting human health and the
environment. Physical location refers to the geologic,
hydrologic, and pedologic characteristics of a site as well
as adjoining lands, surface water, and ground water that may
be impacted in the event hazardous constituents are released
from the facility. A 1983 EPA study (Liner/Location Study by
Ertec Atlantic, Inc.) concluded that proper site selection
and appropriate hydrologic and geologic conditions are impor-
tant factors in maintaining long-term protection of the
environment. In addition, the RCRA reauthorization contains
specific amendments that require the Agency to promulgate
location regulations and to provide location guidance concern-
ing the potential vulnerability of a location to ground water
contamination. This Phase I Guidance Manual was developed
prior to the passage of the RCRA amendments and is not the
"location guidance" called for by the amendments. That loca-
tion guidance (Phase II) will be forthcoming and will be clearly
identified as guidance that fulfills the requirements of the
RCRA amendments. The Agency's Ground Water Protection Strategy
recognizes the importance of hydrogeologic factors in protecting
public health and the environment from contamination related
to a number of waste disposal and product utilization practices.
This Strategy establishes a framework for decision-making
under several Agency programs, and outlines areas for future
1-1
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rulemaking or amendments to existing regulations. The Phase II
Guidance Manual will incorporate the Strategy and will reference
accompanying guidance.
On December 18, 1978, EPA proposed standards to control
the location of facilities in seismic zones, 100-year flood-
plains, coastal high hazard areas, 500-year floodplains,
wetlands, critical habitats of endangered and threatened
species, and recharge zones of sole source aquifers, as well
as specific standards to delimit the location of active por-
tions of facilities with respect to the facility's property
line. Public comments and additional research regarding the
proposed standards were evaluated and on January 12, 1981, EPA
promulgated two of the eight candidate standards: the 100-year
floodplain and seismic zone restrictions. The other six stand-
ards were not promulgated because they either required more
research, were at least partially addressed in regulations
promulgated under laws other than RCRA, or were rejected as
unnecessary to protect human health and the environment, e.g.,
the 500-year floodplain restriction. Revisions to the
floodplain standard were published in the Federal Register
on July 26, 1982.
Based upon a recent review of selected RCRA permit
applications, the Agency has found that many HWLSD facilities
are located in terrains that may cause adverse impacts to
public health and the environment and that the safe and
proper location of such facilities has not been a priority
in the past.
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1.1 SCOPE OF DOCUMENT
The scope of this guidance document covers the physical
location of landfills, waste piles, and surface impoundments.
Some information related to land treatment units is provided.
Land treatment units are subject to many of the same location
concerns as are storage and disposal facilities; however,
land treatment facilities are functionally different from
storage and disposal facilities and require a somewhat differ-
ent approach in defining location acceptability. While
storage and disposal facilities serve as a means of contain-
ment for hazardous constituents, land treatment facilities
are sited and operated to degrade, transform, or immobilize
hazardous constituents. Locational concerns related to land
treatment will be pointed out as appropriate in the text.
Only those parameters important to physical location
are addressed in this guidance manual; engineered features
such as liners are not considered. By separating the engi-
neered features of the hazardous waste land storage and
disposal unit from physical location factors of a site, it
should not be inferred that the Agency considers engineered
elements of a unit to be unimportant. The design of liners,
caps, and other features of HWLSD units is of utmost impor-
tance in minimizing the potential for hazardous waste contam-
inant generation and release. In order to evaluate locational
acceptability, it is important to consider separately the
physical elements that are intrinsic to the natural terrain of
1-3
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a sensitive site. However, in determining whether a location
is acceptable or unacceptable for siting, a permit writer
should first evaluate whether a facility can be designed to
withstand physical events and conditions that exist or that
are likely to occur at the location. If a facility cannot
be designed to withstand such events or conditions, the
permit writer must also evaluate the ability of the location
to minimize the potential for exposure of the public and
environment to the waste in the event that the engineered
containment structures (liner and cover) fail.
1.2 RELATED LOCATION GUIDANCE DOCUMENTS
This guidance manual is,the first phase of a broad EPA
program to establish guidance and standards under RCRA for
the location of hazardous waste land treatment, storage, and
disposal facilities. Conducted by the Office of Solid Waste,
the program is designed to encourage the safe and proper
siting of facilities. This manual is one of a series of
five guidance documents. The four other documents are listed
below as follows:
a. Review of State Siting Criteria for Hazardous Waste
Treatment, Storage, and Disposal;
b. Permit Writers' Guidance Manual for the Location of
Hazardous Waste Land Storage and Disposal Facilities.
Phase II: Vulnerable Hydrogeology Guidance Criteria
and Location Analysis Methods;
c. Permit Writers' Guidance Manual for the Location of
Hazardous Waste Land Storage and Disposal Facilities
Phase II Case Studies; and
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d. Permit Writers' Guidance Manual for the Location of Land
Treatment Facilities.*
* Currently in draft form as "Site Selection Criteria for
Hazardous Waste Land Treatment Facilities," by W.H. Fuller.
Draft project report, ICR810670-01-0. Prepared under a
cooperative agreement between the University of Arizona
and EPA Kerr Laboratory, Ada, Oklahoma.
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2.0 CRITERIA FOR AN ACCEPTABLE LOCATION
The human health and environmental impacts that may occur
when a hazardous waste land storage or disposal (HWLSD) facility
fails differ dramatically depending upon the facility's physical
location. Analysis of the first submissions of RCRA Part B
permit applications indicates that in the event of design and
operating control failure, many new as well as existing HWSLD
facilities are sited in locations having hydrogeologic
characteristics that favor rapid release of waste constituents
and maximize the potential for adverse impact. Permit writers
should evaluate both new and existing HWLSD facility locations
based on the ability of hydrogeologic conditions to encourage
waste containment, reduce contaminant migration, and minimize
adverse impact.
The Agency has established five criteria for evaluating
an acceptable location. These criteria are based on experience
with remedial actions at uncontrolled waste sites and investigations
of various locations of existing RCRA facilities. The term
"location" as used in this manual encompasses the specific
hydrologic, geologic, and pedologic characteristics of the
facility site and related features of the surrounding terrain.
Criteria for an acceptable location are as follows:
a. Site Characterization - The inherent geologic,
hydrologic, and pedologic features of the site and
location at large can be fully characterized.
Complete characterization means that a permit
applicant must be able to delineate the ground-water
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flow path for constituents that may be released from a
unit, determine ground-water flow velocity along the
flow path, and determine subsurface geotechnical properties
necessary to design the unit liner, cover, and impoundment
dikes. Permit applicants seeking Alternate Concentration
Limits (ACLs) and approval of corrective action programs
must also provide additional data regarding contaminant
transport and behavior in the ground-water system
assuming hazardous constituents are released from the
engineered containment structure.
b. High Hazard and Unstable Terrains - The site geology
can provide a stable foundation for the engineered
containment structure and is not subject to likely
events, either natural or man-induced that would impair
the containment structure. The site geology is such
that active ongoing maintenance of engineered containment
measures following unit closure is not required. High
hazard and unstable terrains include those locations
that are prohibited by existing location standards
(i.e., 100-year floodplain and seismic standards) and
those locations that are highly susceptible to events
and conditions that exist or are likely to occur at a
site that could severely damage containment structures
and for which protective measures cannot be designed,
such as seismism, faulting, volcanism, landslides, and
land subsidence.
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c. Ability to Monitor - All potential ground-water flow
paths in the uppermost aquifer along which constituents
can migrate from the regulated unit can be characterized
and ground-water quality can be monitored. In addition,
it must be possible to install monitoring wells to
collect samples of ground water unaffected by leakage
from a regulated unit (i.e., background wells), except
in areas where sources of moisture for ground-water
recharge are negligible. A possible exemption from
ground-water quality monitoring may apply where a unit
is located in a zero recharge zone. This exemption
does not generally apply to surface impoundments and
other facilities that store or dispose of liquid waste
since the presence of these liquids may be a significant
component of recharge to ground water. A zero recharge
zone is an arid terrain characterized by negligible
sources of moisture available to recharge ground water.
The feasibility of the permit writer granting an exemp-
tion in such a location should be based upon a case-by-
case determination.
d. Protected Lands - The facility complies with statutes
and standards applicable to Federally protected land
resource values. Protected lands include:
1. archaeological and historic places,
2. endangered and threatened species habitat,
3. parks, monuments, and scenic rivers,
4. wilderness areas,
5. coastal areas,
6. wildlife refuges,
7. significant agricultural lands, and
8. wetlands.
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e. Ground-Water Vulnerability - The facility is not
within a vulnerable setting above Class I or II ground
water as defined in the Agency's Ground-Water Protection
Strategy or as may be defined directly in the RCRA
amendments of 1984. (The determination of vulner-
ability is described in the Phase II Permit Writers
Guidance Manual for Location of HWLSD Facilities).
Locations that do not satisfy all of the above criteria are
considered "unacceptable" and the permit writer should consider
permit denial. Current regulations/ however, do not provide the
legal basis to deny a RCRA permit at some sensitive locations. For
example, there is no legal basis for permit denial at a location
that satisfies all criteria except the ground-water vulnerability
criterion. However, several existing regulations may serve as a
basis for facility permit denial at locations that do not meet
the requirements of the first four criteria (see Section 3.0
of this manual). When a facility is sited in a sensitive location
but a permit cannot be denied using existing regulations, other
protective measures can be taken (see Section 3 .3 of this manual).
New regulations that directly address the subject of ground-water
vulnerability and other conditions and events discussed in this
manual that are not addressed by existing regulations, will be
developed to supplement current RCRA standards. Until these
regulations are promulgated, siting at sensitive locations that
fail any of the above criteria but for which existing regulations
will not provide the basis for permit denial should be discouraged.
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Permit writers should also inform applicants that expansions of
facilities in these sensitive locations may possibly be denied
on the basis of future regulations.
In evaluating locations against the criteria defined in this
guidance manual, it is important that the permit writer does not
overstate the policies reflected in this document. The five criteria
for location acceptability establish a general set of considerations
relevant to permit issuance that the permit writer should use in
deciding whether the owner/operator is in compliance with all
relevant existing regulations and statutes. It would be a misuse
of this guidance to conclude that each sensitive location described
in this manual is necessarily an unacceptable location for which a
facility permit should be denied. Rather, the permit writer should
use this manual to assist in evaluating sensitive locations where
the facility design, construction, operation, maintenance, and
ground-water monitoring program must be carefully examined. The
determination of whether the facility location is unacceptable
and a permit should be denied depends ultimately on the ability of
the owner/operator to comply with all relevant existing regulations
and statutes cited in this manual.
The following discussion of each location criterion specifies
the existing RCRA regulations and other Federal statutes that
permit writers should apply when evaluating location, and provides
recommendations for dealing with locations that fail any of the
location acceptability criteria. Location case studies based on
information submitted in RCRA facility permit applications are
summarized in this manual. These case studies illustrate how
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the location criteria and related existing regulation and statutes
should be applied. The reader is referred to Section 4.0 of this
manual. An Appendix to the Phase II Location Guidance Manual
currently being developed will contain additional detailed information
about these case study sites as well as other sites now being
evaluated.
2.1 SITE CHARACTERIZATION
Site characterization provides the basic information that both
the permit applicant and permit writer need in order to establish
whether a location meets the remaining criteria for acceptability.
The kind of information and the level of detail needed in a site
characterization varies with the site complexity and the type
of ground-water monitoring and response program (i.e., ACL demon-
strations or corrective actions) applicable to the facility permit.
The two performance objectives for site characterization are:
1. To provide information sufficient to determine
compliance with location criteria b, c, d, and e; and
2 . To provide information sufficient to predict ground-
water transport and movement of constituents released
should the engineered containment unit fail. If a
mathematical simulation model is used, it must be able
to predict contaminant time-of-travel within an error
of no more than one order of magnitude.
RCRA Part B permit information requirements are set forth in 40 CFR
Sections 270.14 through 270.21. The data needed to properly analyze
a particular site (for example, the number, placement, and depth
of observation borings) are not specified by regulation (see Permit
Applicants' Guidance Manual for Hazardous Waste Land Treatment,
Storage, and Disposal Facilities, EPA 530 SW-84-004, May 1984 for
guidance regarding data needs for proper site investigations).
Whether or not the applicant demonstrates that the above
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criteria are met based on the information provided in his appli-
cation depends solely on a thorough review by the permit writer.
An evaluation of permit applications received to date shows
that sites are generally poorly characterized and the data
furnished to the permit writer are deficient. The permit writer
is responsible for reviewing the data submitted in the permit
application, and requesting additional data if necessary, to
ensure that the applicant has adequately characterized the site.
Additional guidance regarding what the permit writer should
look for when making this evaluation will be provided in the
Phase II Location Guidance Manual now being developed (see
Section 5.0 for a discussion of the Phase II Manual).
2.1.1 Geologically-Complex Locations
Certain geologically-complex locations (for example,
karst terrain or fractured bedrock) will require more extensive
investigation to meet the characterization performance objec-
tives. In theory, all sites can be characterized and the
dynamics of the subsurface can be described both quantitatively
and qualitatively given sufficient time and effort. From a
more practical viewpoint, certain sites cannot be fully charac-
terized due to complex hydrogeologic conditions. These latter
sites are locations where permits for existing facilities and
expansion of existing facilities should be denied and construc-
tion of new units should be discouraged. Geologic complexity
refers to variations in the three-dimensional geometry of
geologic units and their physical properties as well as variations
in soil mechanics and site stability. Geologically
simple locations are typically characterized by a "pancake-"
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like arrangement of geologic units having distinct boundaries
that are easily correlated from one soil boring to another.
Physical properties within each unit vary little from one
part to another and physical conditions provide a stable
setting. Locations become more complex when geologic units
are dipping or folding, when units end abruptly or are
discontinuous, when the boundaries become obscure, when
physical properties vary greatly within a layer, or when
soil conditions are unstable. The most complex sites are
those where information about geologic units and their physi-
cal properties cannot be correlated based on boring data.
In the worst case, all sub-surface features appear to be
random and predictions of ground-water movement are more
difficult.
When strategically placed, borings and detailed
observations may provide enough information to show that a
systematic pattern of subsurface layers and physical proper-
ties exists. A reliable characterization is achieved when
additional borings placed between previous borings provide
consistent information about site geometry and hydraulic
behavior.
Terrains commonly found to be geologically complex are:
0 Shallow bedrock areas composed of highly folded,
fractured, or faulted formations
0 Karst areas
0 Alluvial materials
° Certain glaciated regions, and
0 Certain High Hazard and Unstable Terrains (see
Section 2.2)
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2.2 HIGH HAZARD AND UNSTABLE TERRAINS
The high hazard and unstable terrain criterion illustrates
the importance of locating Hazardous Waste Land Storage and
Disposal (HWLSD) facilities within a stable geologic environment
that:
1. results in minimal ongoing maintenance after closure,
2. requires minimal physical modifications to the
site, and
3. minimizes the potential for release of hazardous
constituents due to ground failure and exposure to
severe weather events and geologic processes.
A high hazard and unstable terrain is a location that the
permit writer determines to be unacceptable due to its suscep-
tibility to natural or man-induced events and forces capable
of impairing the integrity of an engineered containment
structure. These events include flooding, vulcanism, land
subsidence, landslides, or seismic displacement, deformation,
and ground motion. A location is likely to be considered a
high hazard and unstable terrain if:
1. it is prohibited by existing location standards
(i.e., the 100-year floodplain standard and seismic
restriction),
2 . it is experiencing existing instability
(e.g., weak and unstable soils) and protective
measures at the facility cannot be designed to
withstand the instability, or
3. historical data indicate that an event is likely to
occur at the site that would impair the engineered
containment structure and protective measures cannot
be designed to withstand the event (e.g. active
subsidence, landslides, seismic events, or volcanic
activity).
Facilities located in a high hazard and unstable terrain
will frequently require perpetual monitoring and maintenance,
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and very likely will require extensive repairs and/or correc-
tive action following a likely natural or man-induced event.
Failure can be rapid as in the case of faulting or flooding,
or gradual as with subsidence or mass movements. Although
the Agency has no evidence to show that any facility can be
designed to withstand natural or man-induced events that are
likely to occur in the future, the permitting standards
currently do not require perpetual responsibility from the
owner/operator. There is no certainty that damages incurred
after termination of the post-closure care period under
§264.117 will be remedied.
EPA does not have specific criteria to operationally
delineate all high hazard and unstable terrains at this
time. The determination that a location is a high hazard
and unstable terrain will be a professional judgment on the
part of the permit writer. This manual, however, describes
six highly sensitive areas that are considered susceptible
to existing instability or future events that, would impair
the integrity of a facility containment structure. The
following subsections describe these terrains (generally
referred to as "sensitive areas") and provides guidance with
respect to permit decisions in these locations. These areas are
as follows:
1. Flood-prone areas
2. Seismic impact zones
3. Volcanic impact zones
4. Landslide-susceptible areas
5. Subsidence-prone areas
6. Weak and unstable soil areas
The permit writer may base his or her decision regarding
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site suitability in sensitive areas upon an evaluation of
information on site and regional location characteristics
submitted by the permit applicant. The permit writer may
identify a location as a high hazard and unstable terrain
unacceptable for siting based upon documented evidence of
existing instability or past events in the immediate area or
past events at other locations that possess similar physical
characteristics that a high hazard event is likely to occur
at the site. Such evidence may include statistics on the
probability of an event occurring (for example, seismic
activity); physical evidence of recent events such as land-
slides, vulcanism, or faulting; or other geologic, geomorphic,
hydrologic, or pedologic data indicating that a location is
likely to experience a future natural or man-induced event.
Locations determined by the permit writer to be high
hazard and unstable terrains are considered unacceptable
locations at which siting of HWLSD facilities should be
discouraged or prohibited on the basis of existing standards
or statutes. Current regulations may provide permit writers
with the authority to deny permits to facilities in locations
where terrain instability already exists or the likelihood of a
natural or man-induced event occurring at the site can be demon-
strated using records of past activity at the site or at sites
with the same geologic properties.
Permitting decisions relative to high hazard and unstable
terrains may vary according to the kind of facility. The princi-
ple distinction between storage and disposal facilities located
in a high hazard and unstable terrain is based on waste residence
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time. Current RCRA standards require that all hazardous waste
must be removed from a storage unit at closure. In contrast,
land disposal facilities and all waste contciined within remain
at a location permanently if certain design and operating stand-
ards are met.
in the description of the sensitive areas that follow,
the permit writer is referred to specific existing RCRA
regulations and other Federal statutes that may apply to
facilities located in high hazard and unstable terrain.
Details of how these regulations can be applied to specific
case study sites are provided in Section 3.0 of this manual.
2.2.1 Flood-Prone Areas
Flooding can occur as a result of stream channel
overflow, tide events, storm surges, and dike or dam failure.
During a flood, wave action and flowing water can overtop
and destroy protective dikes, erode protective covers, or
undermine the containment structure and result in the washout
of hazardous materials. High water levels daring a flood
may cause infiltration through caps or joints between caps
and liners. Floods may also relocate stream channels, thereby
either creating or increasing the potential for damage to
facilities. Following a flood, the facility could have been
damaged to an extent that subsequent floods may more easily
penetrate a unit. Locations more susceptible to floods and
generally within a floodplain include wind and lunar tide
zone and coastal areas, areas below dams, and areas behind
flood or tide dikes.
One of two existing RCRA location standards, 40 CFR
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Section 264.18(b), specifically addresses the location of HWSLD
facilities within the 100-year floodplain. Facilities are not
permitted in the 100-year floodplain unless one of three
conditions are met:
1. the facility is protected, via dikes or other equiva-
lent measures, from washout during a 100-year flood,
or
2. all hazardous materials can be removed to safe ground
prior to flooding, or
3. it can be demonstrated that no adverse effects to
human health and the environment will occur should
flood waters reach the waste.
In addition to a location satisfying the 100-year flood-
plain standard, Executive Order 11990 (Protection of Wetlands)
must be considered by the permit writer for facilities located
on federally-owned lands that may potentially impact wetlands
in the event of a facility failure since wetland areas are
frequently found in or near floodplains. A thorough presenta-
tion of the 100-year floodplain standard and the executive
order is found in Section 3.1.
Permit writers should discourage the location of new HWLSD
facilities and expansions to existing units of disposal facil-
ities within flood-prone areas and deny permits for facilities
in these locations that cannot comply with the RCRA liner
foundation requirements (see Section 3.2.2), the closure
standard (see Section 3.2.3), or the dike integrity standard
(see Section 3.2.4) as well as the 100-year floodplain standard.
Facilities located in flood-prone areas pose a direct threat
to surface waters, wetlands, and adjacent lands since these
areas are particularly susceptible to erosion, wave action,
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and flooding events.
Although the 100-year floodplain standard explicitly
addresses significant threats of flooding to facilities, the
standard does not specifically define the types of locations
that are especially flood prone. These flood-prone locations
and conditions found to exist within certain land areas that
are likely to be located in a 100-year floodplain are described
as follows:
a. Areas Protected by Flood Control Structures
b. Coastal High Hazard Areas (barrier islands and
eroding shorelines)
c. Channel Encroachment Areas
d. Wetlands
Case Study A, summarized in Section 4.0, is provided as an
example to assist the permit writer in evaluating flood-prone
locations. Recommended permit actions for facilities existing
or proposed in such locations are described in the following
subsect ions.
2.2.1.1 Areas Protected by Flood Control Structures
Facilities within the 100-year floodplain protected by general
purpose flood control structures, exclusive of those structures
satisfying the 100-year floodplain standard, may be at jeopardy
should the general purpose flood control structures fail.
Where a facility is located in an area protected by general
purpose flood control structures, the permit writer should
request that the applicant provide the following information
(See 40 CFR Part 270 .14 ( b) (11) ( i i i ) and (iv»: (I) evaluation
C
of the potential for structure failure, (2) resulting impact
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of such a failure on the facility, and (3) a map showing the
elevation of the 100-year flood before and after failure
relative to the location of each unit. Site conditions in
the absence of general purpose flood control structures
should be considered, because the feasibility of removing
waste from a flooded location will generally be difficult to
demonstrate.
2.2.1.2 Coastal High Hazard Areas (Barrier Islands and
Eroding Shorelines) Coastal barrier islands are a special
case of flood-prone area where the land may migrate in response
to subtle changes in sea level. Barrier islands are a string
of sand deposits shaped by wave action and storm surges occur-
ring predominantly along the Eastern U.S. and Gulf of Mexico
shorelines. Currently, barrier islands are migrating landward
in response to a worldwide rise in sea level. Major changes
in land configuration in these areas normally occur during
severe weather and strong tropical storms. Hoffman et al.
(1983) report that a global rise in sea level of between 144
centimeters (4.8 feet) and 217 centimeters (7 feet) by 2100 is
most likely. Along most of the Atlantic and Gulf coasts of
the United States, the rise will be 18 to 24 centimeters (0.6
to 0.8 foot) more than the global average. Land storage and
disposal facilities located on a barrier island may be subjected
to erosion, overwash, and eventual exposure to ocean forces as
subsurface soils migrate away from the facility.
Coastal shorelines also erode at significant rates in
some coastal high hazard areas. Facilities subject to shore-
line erosion may be undercut and ruptured, resulting in waste
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washed into surface waters. Methods to control shoreline
erosion are costly, require continuous maintenance, and have
been known to fail during severe weather.
Where a facility is either located or proposed on a
barrier island or in close proximity to an eroding shoreline,
the permit writer should consider whether the facility can
satisfy the 100-year floodplain standard (see Section 3.1.2).
Because a facility on a barrier island is likely to be jeop-
ardized by eroding shorelines as well as flooding, the permit
writer should also consider the following existing regulations
as grounds for making a decision regarding permit issuance:
0 compliance with closure standards (see Section 3.2.3), and
0 compliance with liner foundation requirements
(see Section 3.2.2).
It is expected that a facility located on a barrier island,
where erosion is likely to create unstable conditions for a
liner foundation, will not comply with the above requirements.
If the permit applicant cannot demonstrate that protective
measures will adequately prevent erosion from occurring at
such a site, permit denial is recommended. otherwise, siting
of facilities on barrier islands should generally be discour-
aged. Facilities in close proximity to an eroding shoreline
should also be evaluated for potential impacts based upon
each of the above existing RCRA standards. Land disposal
facilities located in areas where evidence shows that shore-
line erosion is likely are not expected to comply with the
above design and operating requirements. If protective
measures cannot prevent erosion from occurring in such cases,
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permit denial is recommended. For storage facilities, the
permit writer should request a set back distance from the
shoreline sufficient enough to guarantee no adverse impacts
during the facility active life plus closure period. A
conservative estimate of the annual erosion rate should also
be considered prior to issuing a permit. Case Study A summar-
ized in Section 4.0 illustrates a facility located in close
proximity to estuarine channels that may be subject to shore-
line erosion.
2.2.1.3 Channel Encroachment Areas Channel encroach-
ment areas are those portions of the 100-year floodplain
that will be subjected to erosion as the stream channel
migrates. An analysis of an active floodplain may indicate
meander scars and other features that prove channel migration
has occurred. Only streams flowing in deep channels through
massive rock are not subjected to meandering. Stream bank
erosion and channel migration can be minimized with engineered
structures, but cannot be prevented during the predictable
future without continuous maintenance of these structures.
For facilities located within a channel encroachment area,
the permit writer should consider whether a facility is in
compliance or will remain in compliance with the following
existing RCRA regulations:
0 floodplain standard (see Section 3.1.2),
0 liner foundation requirements (see Section 3.2.2),
and
0 closure standard (see Section 3.2.3).
The permit writer should base permit issuance decisions on
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documented evidence regarding stream channel migration in the
area.
Because channel encroachment areas are locations charac-
terized by continuous physical change, it may be difficult
for owner/operators of storage and disposal facilities to
comply with the liner foundation and closure requirements
over the active life of a unit and the closure and post-closure
periods. If documented evidence shows that encroachment at
the site is likely during this period and if the facility
cannot be designed to mitigate encroachment impacts, permit
denial is recommended for proposed facilities, existing
facilities, or expansions in these locations. Because channel
encroachment areas may be hydrogeologically complex and are
characterized by relatively permeable soils, the following
should be required before issuing a permit to existing facilities
in these locations: (1) Contingent Corrective Action Programs
(see Section 3.3.2), and (2) monitoring of channel migration.
2.2.1.4 Wetlands Portions of the 100-year floodplain may
be composed of wetlands that frequently become flooded. On
December 18, 1978, the Agency proposed a location standard
for wetlands but the standard was never promulgated because
wetland protection was partially addressed under the dredge
and fill program administered by the U.S. Army Corps of
Engineers (COE) pursuant to Section 404 of the Clean Water Act.
The permit writer is responsible for coordinating with the
Corps to assure that the COE properly determines whether or not
a permit applicant is in compliance with the requirements of
the Clean Water Act. The permit writer should also consider
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whether an owner/operator of a facility located on federally-
owned land is in agreement with the directive under Executive
Order 11990 entitled, "Protection of Wetlands", published on
May 24, 1977.
Wetlands are often characterized by organic soils or
other weak soil conditions (see Section 2.2.5). Concerns
for the impact of HWLSD facilities on wetlands are also
discussed under Protected Lands (see Section 2.5.6). Case
Study A in Section 4.0 is provided as an example to assist
the permit writer in evaluating locations characterized by
wetlands.
2.2.2 Seismic Impact Zones
Seismic impact zones are locations subject to surface
deformation, ground shaking, landslides, ground failure,
and subsidence resulting from a seismic event. Surface
faulting, the permanent horizontal and/or vertical displace-
ment of the ground, is one manifestation of a seismic event.
The impact zone may be characterized by a complex of main
faults, branch faults, secondary faults, and associated
deformation features as well as ground motion.
Land storage and disposal units located directly over a
fault may become damaged due to rupture during fault displace-
ment. Units located in close proximity to the fault zone
may be damaged due to ground shaking and associated ground
failure or subsidence. Ground shaking may cause differential
settling of waste within the facility or the ground supporting
the facility, resulting in rupture of the liner, leachate
collection pipes, or cover materials. Ground motion may
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also cause damage to impoundment dikes, especially at exist-
ing units where weak, unconsolidated soils we're used as dike
materials. Weak and unstable soils may liquify, lose strength,
lurch, settle, or slide impairing the structural integrity
of dikes (see Section 3.2.4 on the Dike Integrity Standard
and Section 2.2.6 on weak and unstable soils for existing units
in seismic impact zones). In regions that have experienced
significant seismic activity (see Zones 2 and 3 in Figure
2.2.2-1), seismic impacts must be considered in the design
of new as well as existing units whose damage or failure
could cause widespread adverse impacts on human health and
the environment.
Seismic impacts to units may occur in two forms: the
direct tearing of structures that lie on the fault and the
acceleration of structures within the zone of more intense
motion. Preliminary estimates of the seismic activity experi-
enced in the continental United States is illustrated in
the map of earthquake zoning (see Figure 2.2.2-1). The
zones reflect the level of engineering consideration needed
to ensure good facility design. In Zone 0, experience suggests
no influence of seismic activity on facility design. Zone 1
suggests nominal effects from distant earthquakes or very
small local events. Seismic impacts should be considered in
unit design only if local conditions of subsurface geology
(i.e. faulting) at the site warrant it or if static analysis
of a dike or a dam stability analysis results in a minimum
acceptable factor of safety. Zone 2 implies moderate inten-
sities equivalent to accelerations as great as 0.15g. The
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effect of seismic activity in this zone should be considered
in the design of all facility structures by semiempirical
methods. Zone 3 encompasses all larger earthquakes whose
effect should be evaluated by dynamic analyses. Depending
on local conditions of the location, permit writers should
especially consider what effects seismic impacts may have
upon designed facilities located or proposed in Zones 2 and 3.
An existing RCRA location standard under 40 CFR Part
264.18(a) prohibits the location of any portion of a new
HWLSD facility within 61 meters (200 feet) of a fault active
in the Holocene (during the last 10,000 years). The standard
does not address the impact of landslides or ground failure
that may occur at new and existing facilities affected by
seismic impacts. These conditions are addressed in subsequent
sections of this guidance manual concerning landslide-prone
areas, subsidence-prone areas, and weak and unstable soil
areas. Case Study A summarized in Section 4.0 illustrates a
seismic zone location.
2.2.3 Volcanic Impact Zones
Volcanic activity occurs within well-defined regions and
poses varying degrees of hazard. The type of volcanic acti-
vity is determined by the composition of the magma and the
magma gas content. Basaltic magmas typical of the Hawaiian
Island volcanoes are nonexplosive and form gently sloping
shield volcanoes. Felsic (rhyolite and andesite) magmas
tend to be viscous and contain volatile gas that cause explo-
sive eruptions. Mt. St. Helens and other volcanoes of the
Pacific Northwest are the steep-sided composite volcanoes
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b* MtOMNd With Mrthquik* tctiviiv Tht
of oceurrtfla of damping Mrthq
in Migninp r»>ingi to th* MT
Cttto of 183'
FIGURE 2.2.2-1: SEISMIC ZONING IN THE UNITED STATES
(Algermissen, 1969)
2-22
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typical of felsic magmas. The release of pyroclastic magma,
ash, and lava in an eruption can be accompanied by mud flows,
floods, and avalanches.
Land treatment, storage, and disposal facilities subjected
to volcanic activity may be washed out or eroded by flood or
mud flow, buried by ash or magma, ruptured by ejected material
or impacted by avalanches. Run-off/run-on control and monitoring
systems, for example, may be especially susceptible to damage
from debris flow.
Geologic evidence will indicate the relative activity
of a volcano, and based upon this evidence, a determination
can be made about whether volcanic impacts are likely to
occur at a facility location. Although there is no way of
predicting the exact time of an eruption, the U.S. Geological
Survey (USGS) has delineated zones susceptible to floods,
mud flows, lava flows, and ejected material for the active
volcanoes in Hawaii and the Pacific Northwest. Figure 2.2.3-1
illustrates volcanic impact zones of the forty eight conterminous
United States (Mullineaux, 1976). Permit writers in EPA
Regions IX and X should become familiar with these areas to
determine whether a proposed or existing facility location
is likely to be impacted by volcanic activity. Subsurface and
surficial conditions such as weak and unstable soils, faulting,
and landsliding that may be more conducive in areas of active
volcanoes and that may impact designed structures should also
be considered. Information concerning volcanic impact zones
can be obtained from the U.S. Geological Survey Volcano
Hazards Program and the State Geologist. Technical assistance
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from the U.S. Geological Survey should be requested from:
Coordinator, Volcano Hazards Program
U.S. Geologic Survey
345 Middle Field - Mail Stop 910
Menlo Park, California 94025
(415) 323-8111
Because volcanic eruptions are difficult to accurately
predict, it is unlikely that a permit writer will have a basis
for denying a permit due to the risk of volcanic eruption unless
documented evidence of existing or very recent volcanic activity
in the area is available from the U.S. Geological Survey. If
USGS data indicate that volcanic activity is likely to occur
at a particular facility location and the facility is not designed
to withstand volcanic impacts, the permit writer should discourage
the siting of new facilities, expansion of existing facilities,
and the continued operation of existing facilities in such a
location. For facilities located in areas where evidence of
existing or very recent volcanic activity exists, the permit
writer should consider whether the facility will remain in com-
pliance with the following existing RCRA regulations:
0 Compliance with the closure standard (see Section
3.2.3)
0 Compliance with liner foundation requirements (see
Section 3.2.2)
2.2.4 Landslide-Susceptible Areas
The rapid mass movement of earth materials called land-
slides, rock falls, mudslides, slumps, earth flows or debris
flows, are reported for most steeply sloping lands in the United
States. The timing and extent of a landslide cannot be exactly
predicted; however, areas susceptible to such events may be
characterized by considerable evidence of past occurrences or by
2-24
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J
MAP EXPLANATION
LARGE VOLCANO—Built mostly by repeated eruptions
at a central vent and probably active within
the last 100,000 years. Eruptions range from
quiet to explosive. Volcano flanks are subject
to lava flows and to all other kinds of volcanic
hazards
VOLCANIC VENTS—Known to have been active within the
last 10 million years. Chiefly sites of mildly
explosive to quiet eruptions
VENT AREA—Source of one or more extremely explosive
and voluminous eruptions within the last
2 million years
AREAS SUBJECT TO SPECIFIC VOLCANIC HAZARDS
Lava flows—Areas of groups of volcanic vents termed
"volcanic fields," in which geologically recent
volcanic activity indicates that future eruptions,
chiefly of lava flows and small volumes of ash,
are more likely than in other nearby areas
Hot avalanches, mudflows, and floods
Valley flows subject to burial by hot avalanches
or small- to moderate-size mudflows caused by
eruptions at "relatively active" volcanoes
Valley floors subject to floods and relatively
large but infrequent mudflows caused by erup-
tions at "relatively active" volcanoes
Valley floors subject to burial by hot avalanches
and small- to moderate-size mudflows caused by
eruptions at "relatively inactive" volcanoes
Valley floors subject to floods and relatively
large mudflows caused by eruptions at "relatively
inactive" volcanoes
Volcanic ash and gases
Limits of ashfall-hazard zones; these zones are
subject to deposition of 5 cm or more of volcanic
ash from eruptions of "moderate" to "very large"
volume (see table 21 '
Zone A—Area subject to 5 cm or more of ash from
a "moderate" eruption, similar to the Mount St.
Helens eruption about A.D 1800. Also subject to
deposition of about 1 cm from smaller eruptions
similar to the Mount St. Helens eruption of A.D.
1842
Zone B—Area subject to 5 cm or more of ash from
a "large" eruption, similar to the Mount St.
Helens eruption about 3,400 years ago
Zone C—Area subject to 5 cm or more of ash from
a "very large" eruption, similar to the Mount
Mazama (Crater Lake) eruption about 6,600 years
ago
Sectors in zone A downwind from relatively active
and explosive volcanoes—Most ash (75-80 percent)
from those volcanoes expected to fall within these
areas (see text and fig. 1)
SCALE I 7500000
300
,
100
—I—
200
500
_J
400 500 600 KILOMETERS
FIGURE 2.2.3-1:
Volcanic Impact Zones of the Forty Eight Conterminous
United States (Mullineaux, 1976)
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geologic conditions favoring landslides. A landslide could impact
a HWLSD facility in a variety of ways. For example, the facility
may be carried downslope and ruptured and/or mixed with the
moving earth materials; it may become partially or fully
ruptured in place and the waste exposed; or it may also be covered
and compressed, thus destroying run-on/run-off control systems
and monitoring systems.
A generalized map indicating the relative susceptibility of
areas to landslides is shown in Figure 2.2.4-1. More detailed
maps prepared for a few communities by the U.S. Geological Survey
(USGS) in cooperation with state geological surveys must be used
by permit writers when evaluating if landslide susceptibility
potential exists at a site. The permit writer should contact
both the USGS and the appropriate state survey for assistance in
identifying landslide-prone areas in a specific location. Land-
slide susceptibility is judged from slope, soil, geologic, and
meteorologic conditions by qualified geotechnical engineers
and geologists.
Locations for which there exists geomorphic evidence that
rapid mass wastage is likely, either on the moving mass or in
the slide path, are not expected to meet any of the existing
regulations presented in Section 3.2. The permit writer suspect-
ing that a facility is within a landslide-susceptible area should
request a geotechnical evaluation of landslide potential in
accordance with the permit application information requirements
under 40 CFR Part 270 for liner foundation requirements (see
Section 3 .2.2), the closure standard (see Section 3M 2.3 ) , or the
dike integrity standard (see Section 3.2.4). If such an evaluation
2-26
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indicates that a landslide is likely at the site, that the
facility cannot be designed to withstand the landslide, and
that the liner foundation standard, the dike integrity standard,
or the closure requirement cannot be satisfied, the permit
should be denied by the permit writer.
2.2.5 Subsidence-Prone Areas
The principle locations where land subsidence is likely
to occur are areas of fluid withdrawals, karst terrains, and
subsurface mining. Facilities subjected to subsidence can be
ruptured, deformed, or otherwise damaged such that waste is
directly released to the environment or migration of waste
already leaking from a facility is enhanced. A sudden event
is not a prerequisite for failure of the facility's protective
containment due to subsidence. In certain cases, faulting or
surface deformation may damage the facility structure over a
period of years without obvious manifestations of failure.
Additionally, subsidence-prone areas may be difficult locations
to monitor or in which to implement a corrective action, due to
extensive, uncharacterizable secondary porosity flow paths
(e.g., mine tunnels, earth fissures, and solution cavities).
As of October 1983, eight States prohibit or limit the
location of hazardous waste land disposal operations in mining
or subsidence-prone areas. These States are Arizona, Arkansas,
Delaware, Illinois, Maryland, New Jersey, Pennsylvania, and
West Virginia. Nine States also prohibit or limit the location
of facilities in karst/carbonate areas. These States are
Arkansas, Delaware, Kentucky, Maryland, Minnesota, Missouri,
New Jersey, Pennsylvania, and West Virginia. The States have
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2-28
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various definitions for these site characteristics (Monnig, 1984),
The permit writer should discourage new HWLSD facilities
and proposed expansions to existing facilities from locating
in subsidence-prone areas. For new facilities/ the permit writer
should determine whether the seismic restriction is applicable
in such locations (see Section 3.1.2). In subsidence-prone
areas not governed by the seismic standard, permits may be
denied at new and existing facilities that cannot be designed
to withstand subsidence and consequently, cannot comply with
the following RCRA standards:
0 Ability to Monitor Requirement (see Section 3 .2.1),
0 Liner Foundation Requirement (see Section 3.2.2)
(new units and new portions of existing facilities), and
0 Closure Standard (see Section 3.2.3).
2.2.5.1 Fluid Withdrawal Zones The withdrawal of oil,
gas, and ground water can result in land surface subsidence and
the formation of associated earth fissures and surface faults.
Earth fissures and faults occur due to the compaction of uncon-
solidated sediment as fluid is withdrawn. Subsidence features
may not necessarily occur directly over the cone of depression
of a ground-water well for example, but may appear on adjoining
lands due to variations in subsurface conditions. Holzer (1984)
in a review of ground failure related to ground-water withdrawal
found that earth fissures commonly have lengths of several
hundred meters and are commonly eroded to a width of 1 to 3 m
into gullies at the surface. Faults were found to be a
kilometer or more long with vertical offsets of 0.5 m. The
rate of growth of fissures and faults is relatively slow.
2 -29
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Subsidence may impact HWLSD facilities in several ways.
Faulting may rupture the liner systems or cause differential
settlement within the facility. Earth fissures serve as
planar conduits for infiltrating water, and may route leaking
waste past monitoring wells or otherwise complicate ground-water
flow. Subsidence may change drainage patterns, increase run-on,
or increase the probability of flooding.
A generalized map identifying 14 regions known to be
subsiding as a result of fluid withdrawal is shown in Figure
2.2.5.1-1. The permit writer should use this map only as a
general reference and should not attempt to make a site
specific determination based upon this information. Subsid-
ence impacts can be predicted to some extent at the site
specific level by two approaches: (1) recognition of appro-
priate subsurface conditions at the location, and (2)
monitoring of surface deformation for precursory signals.
Permit writers should investigate the possibility of
subsidence and subsidence impact occurring at any facility
in the southwest U.S. extending over a region from the
Houston area to California. Permitting of new facilities
to be located in such subsidence-prone locations should be
discouraged or denied as appropriate if documented evidence
indicates that subsidence is likely at the location. Owner/
operators of existing facilities located in subsidence-prone
areas that cannot demonstrate through documented observations
that earth fissures and faulting during the active life of
the facility have not occurred should be discouraged from
continued operation or expansion if the facility cannot be
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1. Soutft-cwitraf
2. Southeastern
3. Antetopt Valley
4. Santa Clara Valley
5* rfVfllOftt Vjlwy
6. Lucerne Lake playa
7. Rogers Lake pfaya
8. San Jacmto Valley
9. San Joaquin Valley
10. Yucaipa Valley
II. Ran River Valley
NnaJa
12. Las Vegas Valley
Texas
13. Houston-Galveston region
Utah
14. Millord am
A Earth fissures
V Faults
FIGURE 2.2.5.1-1:
Fluid withdrawal ground failure areas
(after Holzer, 1984).
2-31
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designed to withstand the subsidence. Such evidence may
also be used with other information to determine whether a
facility is in compliance with the RCRA seismic standard
(see Section 3.1.2), the liner foundation requirement, (see
Section 3.2.2), monitoring standards (see Section 3.2.1),
or the facility closure requirement (see Section 3.2.3).
2.2.5.2 Karst Terrain. Areas underlain by limestone
and dolomite are often characterized by extensive solution
cavities, sinkholes, and other features. These locations
are referred to as karst terrain, karst topography, or a
karst plain. Thornbury (1969) provides a thorough description
of karst topography and states four conditions that maximize
development of karst features. These are (1) a soluble rock
such as limestone must be present or at near ground surface,
(2) the soluble rock should be dense, highly jointed, and
thinly bedded, (3) valleys entrenched into the soluble rock
exist, and (4) the region is subject to at least moderate
rainfall. Ground water moving in the joint spaces allows the
soluble rocks to dissolve, leaving solution channels that
expand with time.
Commonly found in karst terrains, sinkhole formation is
an infrequent but destructive event that could cause rupture
of unit liners and covers and eventual collapse of the facility.
Lowering ground-water levels via water supply pumping or
land drainage can accelerate the process of sinkhole collapse.
A karst terrain is also characterized by extensive secondary
porosity capable of transmitting large quantities of ground-
water through complex, unpredictable pathways. Solution
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channels may also connect via 'pipes' through overburden
materials and intercept streams or other runoff (e.g., disap-
pearing streams).
Permit writers should consider the ability of owner/
operators of new facilities and expansions of existing facil-
ities to properly monitor ground-water quality in karst
terrains (see also Section 2.3) as grounds for permit denial.
Permit writers should also consider permit denial in the
case of existing units if the owner/operator cannot demon-
strate the ability of the liner, cover, or other engineered
features of the unit to withstand potential subsidence in
karst terrains (see Sections 3.2.2 and 3.2.4).
2.2.5.3 Mine Subsidence Areas The collapse of mine
tunnels often results in surface subsidence, particularly
where the mines are close to ground surface. To date, approx-
imately one quarter of subsurface mining areas have been
affected by subsidence according to the U.S. Bureau of Mines
(GAO, 1976). The magnitude, extent, and temporal occurrence
of mine subsidence depends upon the thickness and strength
of overlying strata, mine geometry, duration and rate of
mining, and the sequence of mining operation (Dunrud, 1976).
In addition to mine tunnel collapse, collapse of partially
plugged, unrecorded mine shafts have also been reported.
While the mine may not fully collapse, partial subsidence
results in earth fractures that can propagate through hundreds
of meters of strata (Dunrud, 1976).
Subsurface mines pose an additional cpncern to the
location of land storage and disposal facilities, due to
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the complexity of ground-water transport within flooded
mine tunnel networks, and within the fracture pattern that
develops in the overlying materials. Permit writers should
consider the ability of the owner/operator to meet the
ground-water monitoring criterion (see Section 2.3) and
other existing unit-specific design and operation require-
ments (i.e., liner and cover standards) in locations
susceptible to or experiencing mine subsidence. Case Study
B summarized in Section 4.0 is provided as an example to
assist the permit writer in evaluating a mine subsidence
area.
2.2.6 Weak and Unstable Soils
Weak and unstable soils will not provide the proper
foundation for supporting a HWLSD facility or the proper
material necessary for constructing stable embankments.
Facilities located on these soils may be subject to differen-
tial and excessive settlement that will tear liners, rupture
dikes, render leachate collection systems inoperable, and
possibly alter the ground-water flow system. Specific design
and operating requirements for various facilities, for example,
require that liners must be placed upon a foundation or base
capable of providing support to the liner and resistance to
pressure gradients to prevent failure of the liner due to
settlement, compression, or uplift (see unit-specific require-
ments under Sections 264.221, 264.251, and 264.301). Radical
modifications to a site may be required to compensate for weak
and unstable soils that do not provide the proper liner
foundation, base, or stable dike material. The principle
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modification is usually complete removal or replacement of
the low quality earth material.
Geotechnical engineers recognize seven soils or condi-
tions, that, when present beneath a facility, may result in
weak and unstable foundation conditions. These soils and
conditions are the following: (1) organic soils, (2) expan-
sive soils, (3) liquifaction sands, (4) soft clays, (5)
sensitive clays, (6) loess, and (7) quick conditions. The
presence of these soils and conditions can be predicted from
a knowledge of regional geology and site investigation.
Although deposits of weak and unstable soils have been identi-
fied in numerous locations, these soils are commonly found
in recent unconsolidated deposits such as bay mud, and in
locations such as floodplains and deltas. The permit writer
should determine whether the facility is in compliance with
the liner foundation requirement (see Section 3.3.2), facility
closure requirement (see Section 3.2.3), or the dike integ-
rity standard (see Section 3.2.4). A brief description of
each soil type and its significance is presented in the
following subsections.
2.2.6.1 Organic Soils Soils with a significant content
of decaying vegetation can be expected to compress under the
weight of land storage and disposal facilities. Having a
significant organic carbon content as low as ten percent,
these soils are classified as OH, OL, or Pt (peat) under the
Unified Soil Classification System and may also be referred
to as mucks, swamps, wetlands, or marshes. Under the USDA
soil classification system, organic soils are classified
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as Histosols. Organic soil deposits are commonly found in
most humid environments along riverine, lacustrine, and
estuarine systems. Organic soil deposits may be shallow or
as deep as tens of meters and range in size from less than
an acre to several square miles. Unless the deposit is very
thin and deeply buried, these materials should be excavated
prior to construction (see Case Study A summarized in Section
4.0 for an example of a location having this type of weak and
unstable soil).
2.2.6.2 Expansive Soils Soils with a significant
content of shrink-swell clays, such as montmorillonite,
will dramatically change in volume depending upon moisture
content. Shrink-swell clays that have dessicated will possess
cracks and upon wetting, the soil material will swell and the
cracks will close. Locations characterized by expansive soils
may provide uneven foundation support where hazardous waste
units are constructed on such soils. Large increases in
permeability upon exposure to many organic solvents is also
a concern. Expansive soil deposits tend to be thin and
should be excavated prior to construction.
2.2.6.3 Liquefaction Sands Loosely compacted,
saturated sands characterized by round, smooth grains, are
susceptible to liquefaction when subjected to ground motion
(generally due to a seismic event). Ground motion causes
the rearrangement of the sands into a denser configuration.
Immediately following a ground motion, the sand particles
compact to a depth below the natural ground-water table and
no longer support the surficial materials or structures above
2-36
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the water table. The overlying materials or structures are
thus supported temporarily only by water, hence the term
"liquefaction," and are susceptible to sliding or shear failure.
Soils may also liquefy if excessive vibration/ e.g. traffic, occurs
on or adjacent to the affected area. Liquefaction sands are
limited in extent.
2.2.6.4 Soft Clays Clays and mixtures of clay and
sand may possess very low compressive strength and are
very susceptible to shear failure and compression. Called
soft or very soft clays, these materials give an unconfined
compressive strength of under 500 pounds per square foot or
a standard penetration test count of less than four. The
potential for foundation failure is greatest when a facility
extends above grade. Slope stability for dikes and embank-
ments requires thorough examination (See Case Study A
summarized in Section 4.0 for an example of a location having
this type of weak and unstable soil).
2.2.6.5 Sensitive Clays Upon recompaction, certain
clays are weaker than they were in an undisturbed state.
Soils that are four or more times weaker in the disturbed
state are referred to as "sensitive." In some cases, soils
may be weaker by a factor of 20 times in the disturbed state.
Sensitive clays are suspected when Atterberg limits show a
very high liquid limit and an in-situ moisture content near
the liquid limit. Some sensitive clays contain a large
proportion of organic materials. Compensatory engineering
to be relied upon in locations having sensitive clays include
removal of clay, special facility design, precautions to
2 -37
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ensure that the clays are not disturbed, and limiting facility
elevation above the natural grade.
2.2.6.6 Loess Wind deposited materials called loess,
with grain sizes of .005 to .02 millimeters, have very strong
intergranular bonding. The bonding can be weakened upon
wetting which results in settlement and a loss in bearing
strength. The bond may also weaken due to seismic shock.
Bearing strength is also naturally variable in loess deposits.
A loss in strength may eventually result in landslide,
differential settlement, or slope failure. Major loess
deposits are found in the mid- to lower-Mississippi-Missouri
Valley and in southeastern Washington State. Engineering
methods used to compensate for such conditions include
compaction, drainage, or removal of deposits.
2.2.6.7 Quick Conditions Saturated cohesionless (sands)
or low cohesion (including clays) soils subjected to pore water
pressures greater than or equal to intergranular stress will
result in a quick condition. Typically, the hydraulic gradient
in the cohesionless material is vertical upward (known as a
ground-water discharge location). Loads placed on the soils
under a quick condition will be supported only by pore water,
and soils will settle to the extent they are not made buoyant
due to pore water pressure. Liner failure and slope instability
are two potential disruptions that may result in units located
in areas having quick conditions. Areas composed of unconsoli-
dated sediment and artesian aquifer conditions are susceptible
to quick conditions. Compensatory engineering may involve
high maintenance water management systems such as site drainage.
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2.3 ABILITY TO MONITOR AT THE LOCATION
The monitoring criterion is a critical consideration when
making a determination on both the acceptability of a location
and permit issuance. A setting must meet the ground-water
monitoring standards established in 40 CFR Sections 264.92 and
264.97 in order to meet the third criterion for an acceptable
location. General monitoring requirements specify that the
ground-water monitoring system must consist of a sufficient
number of wells, installed at appropriate locations and
depths, to yield ground-water samples from the uppermost
aquifer that represent the following:
1) the quality of background water that has not been
affected by leakage from a regulated unit; and
2) the quality of ground water passing the point of
compliance.
In addition, the owner/operator must comply with permit con-
ditions that ensure that hazardous constituents under Section
264.93 entering the ground water from a regulated unit do
not exceed the concentration limits under Section 264.94 in
the uppermost aquifer underlying the waste management area
beyond the point of compliance during the compliance period.
Whether a facility is in a location that is conducive to
ground-water monitoring can be determined on the basis of
four tests described below.
In the first test, the uppermost aquifer must be identi-
fied and the rate and direction of ground-water flow within
the uppermost aquifer must be specified as required under
Section 270.14(c)(3). Many permit applicants fail to provide
this information in the initial submission of a permit
2-39
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application. If the permit applicant fails to provide adequate
information to correct deficiencies in the permit application
after a reasonable period, the permit writer should consider
the deficiencies as grounds for permit denial.
To meet the second test, the ground-water pathway(s)
for hazardous constituents that may leak from the facility
at failure must be described. This test requires a detailed
characterization of the ground-water flow system. Except
for the most simple geologic systems, the flow system
characterization may require a flow net analysis (to be
described in the Phase II location guidance manual). In
certain circumstances, a simulation of contaminant transport
using an accepted numerical or analytical model calibrated
to specific site conditions may be appropriate. Locations
where the pathways that hazardous constituents would follow
in the event of release from the regulated unit cannot be
concisely determined are considered complex settings, and
therefore, cannot be readily monitored. At such locations,
permits should be denied on the grounds that the location cannot
be monitored unless an exemption from ground-water monitoring
requirements is obtained under 40 CFR Section 264.90 (b)(l),(2),
and (4). Case studies B and D are provided as examples of appli-
cations that fail the second test in this way (see Section
4.0) .
The third test involves the identification of background
ground-water monitoring sites. This test is an expansion of
the flow path test to determine upgradient or off-gradient
background monitoring well sites. Upgradient background wells
2-40
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are preferred for a monitoring network designed to detect
migration of soluble contaminants; however, upgradient
background wells may not always be feasible. Some situations
that require special attention include:
0 waste management areas that are located above water-
table mounds,
0 waste management areas located above aquifers in which
ground-water flow directions change seasonally,
0 waste management areas located above aquifers in which
ground-water flow directions change due to tides,
0 waste management areas that are located close to
another facility's property boundary that is in the
upgradient direction, and
0 waste facilities containing significant amounts of
insoluble and low soluble contaminants with densities
greater than water.
In these and other situations that may arise, the
regulations allow the specification of background wells that
may or may not be upgradient (i.e., off-gradient). The speci-
fication of background well location and depth in these
situations must meet two requirements:
0 the wells must be located and completed at points
least likely to be contaminated should a leak occur,
and
0 a procedure for evaluating whether or not the back-
ground wells are themselves contaminated must be
developed.
Guidance concerning the identification of background moni-
toring well sites and monitoring requirements is found in the
"RCRA Draft Permit Writers' Manual on Ground-Water Protection;
40 CFR Part 264, Subpart F." Generally, the identification
of background monitoring well sites by the permit applicant
should be feasible. In the rare case where background well
2-41
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locations cannot be established, permit denial is required
(unless an exemption is obtained under 40 CFR §264.90 (b)).
The fourth test concerns the practicality of placing moni-
toring wells. Generally, accessible locations at a site exist
for locating both monitoring and background wells. In certain
rare instances, however, appropriate sites for background or
downgradient monitoring wells may be inaccessible due to
rough terrain, protected land restrictions, or an inability
by facility owner/operators to purchase property rights
(necessary when there is insufficient space on the owner's
property outside the waste management area). Where such on-
site conditions present major obstacles in developing a ground-
water monitoring system that provides prompt information on
the presence and extent of ground-water contamination below
the facility, the permit writer should consider permit denial
unless an exemption from monitoring requirements is obtained
under 40 C.F.R. Section 264.90(b).
2.3.1 Zero Recharge Zones
Although appropriate conditions for an exemption from
ground-water monitoring would need to be evaluated by the
permit writer on a case-by-case basis, locations in zero
recharge zones may be considered as one possible setting
where this exemption may be especially appropriate. A zero
recharge zone is a land area that contributes minimal
quantities of water to ground-water recharge. Zero recharge
zones are found only in arid regions like the Basin and
Range physiographic province. Within the Basin and Range
areas, moisture accumulates as snow at mountain ridges of
2-42
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high elevation that envelope the basins. Spring snow melt
discharges off the mountains in small streams. The mountain
streams, however, do not reach the basins except during rare
storm events. The stream flow essentially dries up on the
alluvial fans as the discharging waters soak into the stream
channel as recharge to the ground-water system. The upland
areas located between the dry streams beds are typically
zero recharge zones. Although recharge generally occurs
within narrow reaches of mountain stream channels on the
alluvial fans, run-on and drainage into topographical depres-
sions or geophysical anomalies, and vertical migration below
the root zone and the capillary area, may all lead to recharge
even in arid climates. Case Study C summarized in Section
4.0 illustrates a zero recharge location in the western
United States.
Water movement in an arid zero recharge zone occurs in
a predominantly vertical, cyclic pattern. During infrequent
rain events, moisture infiltrates into the dry soil. Subse-
quent periods of high evapo-transpiration (E-T) remove the
soil moisture. The entire moisture cycle operates in a thin
surface soil horizon between 2 to 3 feet thick. Moisture
within a land disposal facility will move vertically upward,
primarily in response to E-T demand.
To determine whether or not a zero recharge zone exists
in a particular area requires a long term record of potential
evapotranspiration (PET), actual evapo-transpiration (AET),
and precipitation (P). This data is generally available through
local weather service stations and the National Oceanographic
2-43
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and Atmospheric Agency (NOAA). As a general rule, a zero
recharge zone is more likely to exist where: PET > P plus AET
(precipitation + surface runoff) during any month although
vertical recharge may occur in desert climates where the PET
far exceeds the P plus AET in certain settings. In order to
further verify zero recharge at a site, water mass balance,
water dating studies, vadose zone monitoring, and other
techniques may be useful to the permit writer in evaluating a
locat ion.
Zero recharge zones are also associated with thick vadose
zones. Facilities in these zones may be well suited for an
exemption from the ground-water protection standards under 40
CFR Section 264.90(b)(4). In addition, due to the very low
rainfall in these zones, the quantity of leachate generated at
the facility is minimal.
States where zero recharge areas may be found include the
following:
0 Arizona ° Mew Mexico
0 California ° Oregon (eastern)
0 Colorado (western) ° Texas (western)
0 Idaho ° Utah
0 Nevada ° Washington (eastern)
Wyoming (western)
o
The zero recharge criterion and potential for an exemption
from Part 264 Subpart F should only be applied to landfills
and waste piles with liners and leachate collection and
removal systems that comply with the Part 264 standards.
Surface impoundments or any facility that receives liquid
waste should not be considered since the presence of these
liquids may represent a significant component of recharge
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to the ground water.
2.4 PROTECTED LANDS
The protected land criterion alerts permit writers to
consider other existing Federal statutory restrictions on
certain lands when issuing permits to facility owner/operators.
Protected lands may include the following:
1. Archaeological and Historic Places
2. Endangered and Threatened Species Habitat
3. National Parklands
4. Wetlands
5. Wilderness Areas
6. Wildlife Refuges
7. Coastal Areas
8. Significant Agricultural Lands
40 C.F.R. Section 270.3 provides that permits be issued
in a manner and with conditions consistent with requirements
of the following applicable federal laws: the Wild and Scenic
Rivers Act, the National Historic Preservation Act of 1966,
the Endangered Species Act, the Coastal Zone Management Act,
and the Fish and Wildlife Coordination Act. When any of
these laws is applicable, its procedures must be followed.
When the applicable law requires consideration or adoption of
particular permit conditions or requires the denial of a permit,
those requirements also must be followed. section 270.3
informs the permit writer of requirements that exist under
laws other than RCRA that may be applicable to his or her
permit decisions.
HWLSD facilities may be wholly prohibited from locating
in areas like National Parks and Wilderness Areas under
Federal statutory requirements other than RCRA. For some
protected lands, such as sites listed or eligible for listing
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on the National Register of Historic Places, facilities may
only be required to mitigate direct impacts. Other protected
land restrictions may require the applicant to simply obtain
a permit. Wetlands regulated under Section 404 of the Clean
Water Act are an example where a permit is necessary before
siting a facility. Many States now have wetland protection
statutes that have provisions which may exceed the Section 404
requirements. Permit writers should coordinate with the States
to ensure that the appropriate provisions are met.
New HWLSD facilities should not be located on protected
lands. RCRA permit writers should deny RCRA permits for
existing facilities that are not in compliance with the
protected land statutes, if required permits or permission
from the appropriate regulatory authority have previously
been denied. The National Environmental Policy Act (NEPA)
regulations implemented under 40 CFR Part 6 (Subpart C) by
the Environmental Protection Agency describe more specifically
various Federal laws and executive orders that apply to
protected lands. Permit writers should coordinate with the
NEPA Compliance staffs in the Regions as well as with the
appropriate Federal agencies to encourage routine consultation
regarding the applicability of various protected land statutes
in facility permitting. The protected land statutes and
regulations are listed in Table 2.4-1.
The following subsections briefly describe various types
of protected lands and cites the applicable statutory authority
and restrictions that apply in permitting the HWLSD facilities.
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2-46
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proposed in a protected land (wetlands) settings.
2.4.1 Archaeological and Historic Places
The National Historic Preservation Act (NHPA) of 1966
(as amended in 16 U.S.C §§ 470 et. seq.) provides for the
inventory and limited protection of valuable archaeological
and historic places. NHPA establishes an Advisory Council
on Historic Preservation and a National Register of Historic
Places. The criteria for evaluating whether a location has
historic significance and warrants inclusion on the National
Register are as follows:
"The quality of significance in American History, architec-
ture, archaeology, and culture is present in districts,
sites, buildings, structures, and objects of State and
local importance that possess integrity of location, design,
setting, materials, workmanship, feeling,, and association,
and
1. that are associated with events that have made a
significant contribution to the broad patterns of
our history; and
2. that are associated with the lives of persons
significant in our parts; or
3. that embody the distinctive characteristics of a
type, period, or method of construction, or that
represent the work of a master, or that possess
high artistic values, or that represent a signifi-
cant and distinguishable entity whose components
may lack individual distinction; or
4. that have yielded, or may be likely to yield, in-
formation important in prehistory or history . . ."
The NHPA is enforceable through Section 106 (16 U.S.C.
§§ 470(f)) which provides that, prior to the expenditure of
any federal funds or the issuance of any federal license,
the federal agency involved must take into account the effect
of the project on any district, site, building, or structure
that is included or is eligible for inclusion in the National
2-48
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Register. The Advisory Council must also be afforded a
chance to comment on the project through the "Section 106"
process. The 106 review process is initiated through the
state official designated as the "State Historic Preservation
Officer." As a result of the 106 review, specific actions
to mitigate effects may be required.
Since RCRA permits constitute a federal license, the 106
review process is required and must be implemented as recog-
nized in 40 C.F.R. Section 270.3(b). The Regional Administrator
is required to adopt measures, when feasible, to mitigate
potential adverse effects of the facility upon properties
listed or eligible for listing in the National Register. The
procedures for carrying out the Section 106 process are detailed
in 36 C.F.R. Part 800.
2.4.2 Endangered and Threatened Species
The Endangered Species Act of 1973 (16 U.S.C. §§
1531-1543) provides protections for listed endangered and
threatened species of animals and plants. The possible
impacts of siting a land disposal facility in an endangered
and threatened species habitat may include removal of critical
habitat necessary for the survival of the species, restricting
the movement of species, and degrading the environment near
the facility. The Agency is obligated under Section 7 of
the Endangered Species Act to ensure that permitted facilities
are not likely to jeopardize the continued existence of any
endangered or threatened species or adversely affect its
critical habitat (see 40 CFR Section 270.3(c)). Generally,
the Agency interpretation of this obligation is to prohibit
2-49
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the siting of HWLSD facilities within endangered or threat-
ened species habitat. Permit writers are obliged to use the
authority of this Act as grounds for permit denial in appro-
priate cases.
2.4.3 Parks, Monuments, and Scenic Rivers
National parks, monuments, preserves, seashores, park-
ways, battle field parks, and historic parks are protected
under the Organic Act of 1916. The Organic Act established
the National Park Service to administer the above listed
lands with the objective of "conserving scenery and the
natural historic objects and the wildlife therein. . . by such
means as will leave them umimpaired for future generations."
Lands administered by the National Park Service are generally
unacceptable for the location of HWLSD facilities. An excep-
tion is where the location of such a facility on these protected
lands is authorized by Congress.
The Wild and Scenic Rivers Act (16 U.S.C §§ 1273 et.
seq.) protects rivers and adjoining lands designated as wild
and scenic by Congress. Section 7 of the Act prohibits the
Regional Administrator from licensing the construction of
any water resources project that would have a direct, adverse
effect on the values for which a national wild and scenic
river was established. Generally, the Agency interpretation
of this obligation is to also discourage siting of HWLSD
facilities in these riverine areas and adjoining lands to the
extent that such facilities may impact these protected areas.
State and local parks, natural areas, scenic rivers, or
recreational areas are likely to be protected under State
2-50
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statutory and/or regulatory authority. The permit writer is
advised to consult with State and local authorities should a
facility be located in or within close proximity to such areas,
2.4.4 Wilderness Areas
The Wilderness Protection Act of 1964 (16 U.S.C. §§
1131-1136) designates wilderness areas within public lands
that include National Parks, National Wildlife Refuges,
National Forests, and Bureau of Land Management Lands.
Designated wilderness areas cannot be used as sites for
HWLSD facilities or land treatment units without Congres-
sional approval.
2.4.5 Coastal Areas
The Coastal Zone Management Act, 16 U.S.C. §§ 1451 et
seq., requires that all Federal activities in coastal areas
be consistent with appproved State Coastal Zone Management
Programs to the maximum extent possible. If a facility
permitting action by the Agency may affect a coastal zone
area, the permit writer is required to assess the impact of
the permitted facility on the coastal zone. If the facility
significantly affects the coastal zone area and the State has
an approved coastal zone management program, the permit writer
is obliged to notify the appropriate State agency and recom-
mend that the State examine the issues of siting in the
coastal zone as appropriate under the State's program (see
40 CFR Section 6.302(d)).
2.4.6 Wildlife Refuges
National Wildlife Refuges are managed by the U.S. Fish
C.
and Wildlife Service for the primary purpose of developing a
2-51
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national program of wildlife and ecological conservation and
rehabilitation. Refuges are established for the restoration,
preservation, development, and management of wildlife and
wildlife habitat, for the protection and preservation of
endangered or threatened species and their habitat, and for
the management of wildlife and natural habitats to obtain
the maximum benefits from these resources. 50 CFR Part 27.94
specifically prohibits the draining or dumping of oil, acids,
pesticide waste, poisons, or any other chemical waste into
refuge areas, or otherwise, polluting any waters, waterholes,
streams, or other areas within a refuge. A right-of-way
permit can be retained for activities in a refuge provided
that the activity is found to be compatible with the purpose
of the refuge. The Agency does not consider c\ HWLSD facility
compatible with the purpose of a refuge; therefore, such
locations are generally unacceptable for siting. Permit
writers should also consider the degree to which proposed or
expanded existing facilities may impact wildlife refuges
that are within or in close proximity to facility property
boundari es.
2.4.7 Significant Agricultural Lands
Until recently, only a few states provided regulations
to protect agricultural lands by restricting the location of
HWLSD facilities. The U.S. Department of Agriculture (USDA)
Soil Conservation Service has promulgated a final rule under
7 CFR Part 658. The Farmland Protection Policy seeks to
minimize the conversion of farmlands from agricultural to non-
agricultural uses. The rule establishes criteria that Federal
2-52
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programs must consider and directs Federal programs to study
alternative actions toward protecting farmland resources.
Technical assistance is available from the USDA to Federal,
State, and Local Agencies in assessing farmland protection
issues. Permit writers should refer to the Federal Reg ister,
Volume 49, No. 130, pg. 27716 (July 5, 1984) and should
coordinate with the USDA Soil Conservation Service for further
information about the Farmland Protection Policy.
It has always been the general policy of the Agency to
protect, to the extent possible, environmentally significant
agricultural lands from conversion to uses which result in
its loss as a food production resource or environmental
resource. Before undertaking a permit action, the permit
writer should consider whether there are significant
agricultural lands in the area of the facility. If these
areas are identified, direct and indirect effects of the
facility on the land should be evaluated and adverse effects
avoided or mitigated, to the extent possible. The Agency's
policy regarding agricultural lands is described in a document
entitled, "Policy to Protect Environmentally Significant
Agricultural Lands" (September 8, 1978). Permit writers
should contact their Regional NEPA Compliance Staff for
further information regarding this Agency Policy (see 40 CFR
Section 6.302(c)).
2.4.8 Wetlands
Wetlands are land areas where the water table is at,
near, or above the land surface long enough to promote the
formation of hydric soils and to support the growth of
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hydrophytes (Cowardin, et al. , 1979). Hydric soils are
soils, that for a significant period of the growing season,
have reducing conditions in the major part of the root zone
and are saturated within 25 cm of the surface. The Agency
has two principal concerns with regard to the location of
land disposal facilities in wetlands. The first is the
impact that new facility construction and ope;ration will have
upon the wetland environment. The second is the potential
impact of accidental discharges of hazardous waste into the
wetland environment.
HWLSD facilities located in a wetland will result in
the direct removal of wetland vegetation and may also alter
wetland hydrology and degrade adjacent wetland areas through
the disposal of spoil material and release of sediment.
The above concerns are addressed in two Federal permit
programs: the NPDES and dredge and fill permit programs
under Section 404 of the Clean Water Act, and by Presidential
Executive Order 11990 for wetlands located on Federally-owned
lands. The Section 404 dredge and fill permit program,
administered by the U.S. Army Corps of Engineers, was estab-
lished to prevent the discharge of dredge and fill materials
into navigable waters of the United States and adjacent
wetland where such discharge will have an unacceptable
adverse effect on municipal water supplies, shellfish beds,
fishery areas, wildlife areas, or recreational areas. Navi-
gable waters, as interpreted by the courts for Section 404,
mean all waters of the United States. However, not all
wetlands as classified by Cowardin, et al. (1979) are covered
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by Section 404. The Corps of Engineers has issued general
use permits for selected 404 wetlands, most notably, wetlands
within the headwaters of watersheds (the upper 5 square
miles of a stream watershed). In areas of potential wetland
impacts, planned discharges from land disposal facilities
would technically require a National Pollution Discharge
Elimination System (NPDES) permit. This permit system has
also been established through the Clean Water Act.
Although it does not carry the force of a law, Executive
Order 11990 (May 1977) directs Federal agencies to avoid
undertaking or providing assistance for new construction of
projects located on federally-owned wetlands unless there is
no practical alternative. In cases where there is no alter-
native site, all measures must be taken to minimize harm to
the wetland.
The Agency previously determined that these existing
programs adequately protected wetlands from adverse impacts
of construction and siting of hazardous waste facilities and
from adverse impacts due to discharges originating from
these facilities. However, in the process of developing new
location standards, the Agency will need to consider more
closely that certain wetlands create specific hydrologic set-
tings of ground-water flow that may provide conditions
conducive to contamination migration when facility designs
fail.
Since hazardous waste contamination may pose a much more
significant threat than fill or dredged materials when intro-
duced into a wetland setting, a preliminary assessment of
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wetland impacts should be made on a case-by-case basis.
In the event that preliminary review of the permit
application shows that the facility is to be located on
wetlands, the permit writer is advised to contact the Corps
of Engineers District Office and EPA's Regional Wetlands
Coordinator for verification and permitting consultation.
The Corps of Engineer District Office can provide a
wetlands survey of the proposed site. The operational defini-
tion and identification of wetlands is not an exact science.
The Corps of Engineers defines wetlands as "those areas that
are inundated or saturated by surface or ground water 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."
(see 40 C.F.R. Section 230.3).
2.4.9 State and Local Considerations
In addition to the protected lands described above, state
and local governments may also protect other sensitive
environmental areas. Selected watersheds, for example, may
be protected in order to ensure uncontaminated water supplies
to a water supply reservoir. The means of protection often
include restrictions on land use and may prohibit the siting
of hazardous waste facilities. The permit writer should
notify the appropriate State hazardous waste management
agency regarding these and other sensitive locations and
recommend that the State examine the siting issues as appro-
priate under State law.
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2.5. GROUND-WATER VULNERABILITY
The vulnerable ground-water criterion is designed to
protect Class I and Class II ground waters established under
the Agency's Ground-Water Protection Strategy (G-WPS). The
1984 amendments to RCRA require the Agency to develop guidance
criteria for ground-water "vulnerability".
The Strategy outlines how various Agency program offices
will operate, revise, and/or amend existing regulations to
assure the protection of ground-water resources. Location
guidance and future location standards for RCRA facilities
are major elements toward meeting this goal.
The G-WPS keys regulatory activities to the following
three classes of ground water, the class being largely dependent
upon the use, value, and vulnerability of the resource:
I. Special Ground Water (Irreplaceable and Ecologically
Vital)
II. Current and Potential Sources of Drinking Water and
Waters Having Other Beneficial Uses
III. Ground Water Not Considered a Potential Source of
Drinking Water and of Limited Beneficial Use.
When implemented, the Ground-Water Protection Strategy
will have far reaching implications for both new and existing
RCRA facilities located over various classes of ground water.
Table 2.5-1 indicates possible means of controlling facility
siting for various ground-water classes. Ultimately, the
Agency may ban through regulations the siting of new and
existing HWLSD facilities in vulnerable settings above Class
I and Class II ground water. Until these rules are promul-
gated, proposals to site new facilities or expand existing
2-57
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HWLSD facilities in these locations should be discouraged.
A test for determining vulnerability of ground water
to contamination from RCRA facilities will be presented in
Phase II of the Location Guidance. This test is being
developed in cooperation with the Office of Ground-Water
Protection which is characterizing vulnerability within a larger
context. Currently under development, the Location Case
Studies Appendix to be included as part of Phase II will
illustrate how the permit writer should determine whether or
not the ground-water vulnerability criterion is met in a
number of specific locational settings. In general, locations
characterized by short time of travel of ground water along
a ground-water flow line from the facility through the ground-water
system are considered vulnerable settings.
At present there are no existing regulations to prohibit
the siting of new or existing HWLSD facilities located in
vulnerable settings above Class I and Class II ground water.
Until comprehensive location standards are promulgated, and
after distribution of the Phase II RCRA Location Guidance
Manual, permit writers should discourage siting of new facili-
ties, expansions to existing facilities, and permitting of
existing disposal facilities in these areas by relying upon
one or more of the following:
1. requiring contingent corrective action programs and
supporting evidence that such programs can be
implemented in a timely fashion (see Section 3 .3.2),
2. consider the ground-water classification in evalua-
ting alternate concentration limits (ACLs) in the
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facility's ground-water protection standard
(see Section 3.3.1), and
3. restrict the use of exclusions of Appendix VIII
constituents from ground-water monitoring (see
Sect ion 3.3.1).
The following subsections describe the three ground-water
classes and regulatory considerations discussed in the G-WPS.
Various terms in quotes will be defined in guidance documents
developed by the Agency's Office of Ground-Water Protection.
Various methods for determining vulnerability of ground
water beneath a locational setting are currently being deve-
loped. These methods will be made available to the permit
writer for evaluating site vulnerability in the Phase II RCRA
Location Guidance.
Classification and delineation of ground water is currently
under way in many States. Until the issue of equivalency
between State and Federal classification systems is resolved,
the classification of the uppermost aquifer will be determined
on a case-by-case basis through the RCRA permitting process.
Facility locations in vulnerable settings above Class I and
Class II ground-water systems will be considered unacceptable.
2.5.1 Class I Ground Water
Class I ground water is defined on the basis of one of
the following two factors:
1. "Irreplaceable source of drinking water." These
include ground water located in areas where there
is no alternative source of drinking water (islands,
peninsulas, isolated ground water over bedrock) or
an insufficient alternative source for a substantial
population; or
2-60
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2. "Ecologically vital," in that the ground water con-
tributes to maintaining either the base flow or
water level for a particularly sensitive ecological
system that, if polluted, would destroy a unique
habitat (e.g., those associated with wetlands that
are habitats for unique species of flora and fauna
or endangered species).
The siting of new HWLSD facilities and permitting of
existing HWLSD facilities in vulnerable settings above Class
I ground water should be discouraged. The RCRA Part 264
regulations will eventually incorporate location standards
that ban new HWLSD facilities that pose a risk to Class I
ground water. These regulations may also force phase-out of
existing facilities in these locations. Where contamination
has occurred within the boundary of existing facilities,
ground-water cleanup will be required to the appropriate
level, either to drinking water standards or background
levels during the active life of the unit. Issuance of
alternate concentration limits (ACLs) will not normally be
appropriate in these areas.
2.5.2 Class II Ground Water
Class II encompasses all other ground water "currently
used" or "potentially available" for drinking water and other
beneficial use, whether or not it is particularly vulner-
able to contamination. This class comprises the majority of
usable ground water in the United States. New HWLSD facili-
ties in vulnerable settings above currently-used Class II
ground water are to be discouraged until location standards
are promulgated that may ban siting of such facilities in
these settings. At closure, certain existing facilities in
extremely vulnerable locations may need to close under current
2-61
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closure requirements for storage facilities where waste must
be removed from the unit. Existing facilities will be subject
to current ground-water protection standards with cleanup to
drinking water standards or background levels required as
appropriate during the active life.
For both new and existing facilities in non-vulnerable
settings above Class II ground water, the requirements will
differ based on the specific current or potential use of the
ground water. Where ground water exists in a non-vulnerable
setting and is currently used for drinking water or other
beneficial purposes, new and existing facilities will be
subject to current RCRA ground-water protection requirements,
with cleanup to drinking water standards, background levels,
or alternate concentration limits (ACLs) as appropriate.
For sites which can impact potential sources! of ground water,
the same policy will generally apply. However, for these
ground waters, the Agency may, allow various plume management
options that take into account such factors as the probability
of potential ground-water use and the availability of cost-
effective methods to ensure water quality at the point of use.
Cleanup policies for these categories of ground water
will also vary, depending upon the use, value, and vulnerability
of the ground water. The most stringent requirements will apply
where contamination is caused by a hazardous waste facility.
If the ground water is defined as having a current use, the
general policy is to eliminate the source of contamination
and treat contaminated ground water to the highest technically
feasible level required to protect human health and the
2-62
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environment. The Agency recognizes that there are circumstances
which must be approached on a case-by-case basis, in which
mitigating the source of contamination and managing the
plume will be the most reasonable course of action. The
Agency plans to consider this approach when such circumstances
arise in setting alternate concentration limits (ACLs) and
approval of corrective action plans.
2.5.3 Class III Ground Water
Ground water that is saline or otherwise contaminated
beyond levels which would allow for drinking or "other bene-
ficial use" is considered Class III ground water if it is
"hydrogeologically isolated" as defined in the classification
guidance being developed under the Ground-Water Protection
Strategy. This includes ground water with a Total Dissolved
Solids (TDS) level over 10,000 mg/1 or that is so contaminated
by naturally-occurring contaminants or by human activity
(unrelated to a specific hazardous waste land disposal site)
that ground water cannot be cleaned up using methods generally
employed in public water system treatment.
The Agency will continue to require facility design and
operating standards for Class III ground water to ensure no
migration to Class I and Class II ground water, and to prevent
a discharge to surface water that could adversely affect
human health or the environment. Since the ground water is
not usable, the issuance of alternate concentration limits
will often be appropriate thus minimizing the need for cor-
rective action for additional contamination resulting from
c
facilities over Class III ground water.
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3.0 EXISTING REGULATIONS TO EVALUATE LOCATIONS
Various existing regulations may be relied upon as a
basis for making permit decisions about a RCRA facility
location and whether or not it is appropriate for safe and
proper siting. The purpose of this section is to provide
the permit writer with a full citation of RCRA facility
performance standards and Federal Statutes that implicitly
involve hydrogeologic factors for addressing acceptable
locations. Table 3.0-1 is a summary of location criteria
and applicable existing RCRA regulations. The permit writer
should consider separately each criterion for which a facility
location will be tested by examining whether or not the
facility is in compliance with referenced existing regulations.
3.1 EXISTING RCRA LOCATION STANDARDS
Two standards for the location of hazardous waste land
treatment, storage, and disposal (HWLTSD) facilities — seismic
restrictions (40 CFR Part 264.18(a)) and floodplain standards
(40 CFR Part 264.18(b)) -- have been promulgated. Guidance for
determining compliance with these location standards is availa-
ble in an EPA document entitled, "Permit Applicants' Guidance
Manual for the General Facility Standards of 40 CFR Part 264"
(SW-968, October 1983).
3.1.1 Seismic Standard
The seismic standard prohibits siting of portions of new
HWLTSD facilities within 61 meters (200 feet) of a fault known
to be active during Holocene time (a period occurring during the
last 10,000 years). The intent of this standard is to ban
3-1
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new facilities in locations on or near faults that are likely
to experience displacement in the future. Geologic evidence
indicates that faults which have moved in recent times are
more likely to move in the future. "Fault" is defined to
include the various forms of faults (i.e., main, branch, or
secondary) that may not result in surface expression. The
61 meter setback was based on available data indicating that
most ground deformation due to fault movement occurs within
61 meters to 91 meters (200 feet to 30 0 feet) of the active
fault. The available data also indicated that deformation
generally decreases rapidly with distance from the fault.
Regulatory language and definitions from 40 CFR Part 264.18.
(a) are provided as follows:
(a) Seismic considerations. (1) Portions of new
facilities where treatment, storage, or disposal of
hazardous waste will be conducted must not be located
within 61 meters (200 feet) of a fault which has
had displacement in Holocene time.
(2) As used in paragraph (a)(l) of this Section:
(i) "Fault" means a fracture along which rocks on one
side have been displaced with respect to those on
the other side.
(ii) "Displacement" means the relative movement of any
two sides of a fault measured in any direction.
(iii) "Holocene" means the most recent epoch of the
Quaternary period, extending from the end of the
Pleistocene to the present (a period of 10,000 years)
NOTE: Procedures for demonstrating compliance with
3-3
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this standard in Part B of the permit application
are specified in § 270.14(b)(11). Facilities that
are located in political jurisdictions other than
those listed in Appendix VI of Part 264, are
assumed to be in compliance with this requirement.
The seismic restriction does not explicitly specify all of
the concerns inherent in the location of HWLTSD facilities in
areas susceptible to seismic impacts. As presented in Section
2.0, ground motion effects such as faulting or earth fissures
resulting from nonseismic events, e.g., land subsidence due
to fluid withdrawal, are also of major concern. The major
omission from the current standard is a means of accounting
for these ground motion effects both within and beyond 61
meters (200 feet) of a fault. The existing standard solely
addresses fault deformation and displacement impacts.
Ground motion may also cause ground failures outside of the
61 meters (200 feet) distance that may impact a facility
including landsliding, liquefaction, settlement and lurching,
or accelerated soil creep. The potential for seismically-
induced ground failure is related to specific geologic,
hydrologic, and pedologic characteristics of each location
evaluated. Ground failure-prone locations may be considered
high hazard terrains which overlap, to some extent, with
seismic impact zones, landslide-susceptible areas, and weak
and unstable soils under certain conditions.
The Agency may consider making revisions to current RCRA
seismic restrictions to more explicitly address the concerns
outlined above. The permit writer is referred to other existing
3-4
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regulations presented in Section 3.2 for locations suspected of
having a susceptibility to ground motion-induced ground failures.
3.1.2 Floodplain Standard
The floodplain standard prohibits the location of HWLTSD
facilities within the 100-year floodplain unless one of the
following three criteria are met: a) the facility is designed,
constructed, operated, and maintained to prevent washout of
any hazardous waste by a 100-year flood, b) the applicant can
demonstrate that the waste can be safely removed before flood
waters can reach the facility, or c) for existing HWLTSD
facilities, the applicant can show no adverse effects on human
health or the environment will result if a washout occurs.
The 100-year flood was selected as the basis for this standard
because it is the most widely used parameter in other Federal
programs and has been operationally defined in a large number
of communities.
In the January 12, 1981 Federal Register, the Agency chose
not to adopt two other standards related to flooding and flood-
plains. A wetlands standard under RCRA is currently not in
effect since existing programs administered under the NPDES
requirements and Section 404 of the Clean Water Act (CWA)
has been relied upon to adequately protect wetlands from any
adverse impacts of facility construction and siting. The
permit writer should coordinate with the appropriate Federal
Agency to be sure that the facility owner/operator complies
with existing wetland protection requirements and to deter-
mine a course of action if the owner/operator is not in
compliance. The permit writer should determine whether or
3-5
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not the owner/operator is also seeking approval of other
Federal permits before issuing a RCRA facility permit (See
Section 2.4.4) .
A "Coastal High Hazard" restriction to prohibit facili-
ties from siting in such areas may not be widely understood to
be included as part of the RCRA floodplain standards. However,
coastal high hazard areas are generally located within the
100-year floodplain and, therefore, are loccitions that are
also protected under the floodplain standard. These areas
are subject not only to flooding but also to wave action
during coastal storms. The impacts of wave action should be
considered to the extent that information about the design,
construction, maintenance, and operation of a facility to
protect against flooding and washout can be required to
support the permit application. Two types of coastal high
hazard areas, barrier islands and eroding shorelines, may
not be able to satisfy existing standards for liner founda-
tion stability. The permit writer reviewing a permit appli-
cation for an existing, proposed, or expanding facility in a
barrier island setting or a shoreline subject to erosion is
referred to Sections 3.2.2 and 3.2.4 of this guidance manual.
Such locations should also be subject to the supplementary
restrictions outlined in Section 3.3.
The floodplain standard and accompanying definitions under
40 CFR Part 264.18(b) are as follows:
(b) Floodplains.
(I) A facility located in a 100-year floodplain must be
designed, constructed, operated, and maintained to
3-6
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prevent washout of any hazardous waste by a 100-year
flood, unless the owner or operator can demonstrate
to the Regional Administrator's satisfaction that:
(i) Procedures are in effect which will cause the waste
to be removed safely, before flood waters can reach
the facility, to a location where the waste will not
be vulnerable to flood waters; or
(ii) For existing surface impoundments, waste piles, land
treatment units, and landfills, no adverse effects
on human health or the environment will result if
washout occurs, considering:
(A) The volume and physical and chemical characteristics
of the waste in the facility;
(B) The concentration of hazardous constituents that
would potentially affect surface waters as a result
of washout;
(C) The impact of such concentrations on the current or
potential uses of water and water quality standards
established for the affected surface waters; and
(D) The impact of hazardous constituents on the sediments
of affected surface waters or the soils of the
100-year floodplain that could result from washout.
(2) As used in paragraph (b)(l) of this Section:
(i) "100-year floodplain" means any land area which
is subject to a one percent or greater chance of
flooding in any given year from any source.
(ii) "Washout" means the movement of hazardous waste
from the active portion of the facility as a result
3-7
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of flooding.
(iii) "100-year flood" means a flood that has a one
percent chance of being equalled or exceeded in
any given year.
3.1.2.1 Wetland Executive Order
Besides the RCRA 100-year floodplain standard, the
permit writer should consider prevention of impacts to wet-
lands under Executive Order 11990 (see 40 C.F.R. §§ 6.302(a))
when evaluating facilities located on federally-owned property.
Wetlands are commonly found in areas adjacent to floodplain
locations. Executive Order 11990 directs Federal Agencies
to prevent long- and short-term adverse impacts associated
with the destruction or modification of wetlands located on
federally-owned property and to avoid direct or indirect
support of new construction in such wetlands. Wherever
there is a practical alternative, the Agency is obligated to
minimize the destruction, loss, or degradation of wetlands
when considering issuance of a RCRA permit. The Agency must
consider how a facility may effect both the survival and
environmental quality of wetlands. Among these factors are:
a. public health, safety, and welfare including:
water supply, quality, recharge, and discharge;
pollution; flood and storm hazards; and sediment
and erosion;
b. maintenance of natural systems, including
conservation and long-term productivity of
existing flora and fauna; species and habitat
diversity and stability; hydrologic utility,
fish, wildlife, timber, and food and fiber
resources; and
c. other uses of wetlands in the public interest
including recreational, scientific, and cultural
uses .
3-8
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3.2 EXISTING RCRA DESIGN AND OPERATING STANDARDS
In addition to the seismic and floodplain standards,
certain RCRA regulations under 40 CFR Part 264 serve as the
basis for denying a permit to owners/operators of HWLSD
facilities in locations characterized by poor hydrogeologic
conditions. Most of these regulations may not have been
previously recognized by permit writers as a basis for
denying a permit in cases where facilities are located in
unacceptable settings. By their nature, certain specific
design and operating performance standards require hydrologi
and geologic conditions that provide locational settings
conducive to safe and proper siting of facilities.
Four existing RCRA regulations that have inherent hydro-
logic and geologic factors are listed below and are further
described in subsequent sections. These are:
0 Monitoring Requirements
0 Liner Foundation Requirements
0 Closure Performance Standard
0 Impoundment Dike Foundation Requirement
As currently written, the RCRA regulations allow the
owner/operator to demonstrate that poor geologic and hydro-
logic conditions at the facility location may be improved
through proper unit design and operation. The permit writer
is responsible for determining whether the owner/operator
has made a satisfactory demonstration.
3.2.1 Monitoring Requirements
General ground-water monitoring requirements under 40
CFR Part 264, Subpart F, entitled Ground-Water Protection
Standards, are found in Sections 264.92 and 264.97. The
3-9
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components of these sections that can be used to evaluate
locational acceptability are provided below:
0 Pursuant to Section 264.92 (Ground-Water Protection
Standard), the owner/operator must comply with condi-
tions specified in the facility permit that are designed
to ensure that hazardous constituents as defined in
Section 264.93 entering the ground water from a regulated
unit do not exceed the concentration limits established
under Section 264.94 in the uppermost aquifer underlying
the waste management area beyond the point of compliance
established under Section 264.95 during the compliance
period as defined in Section 264.96.
0 Pursuant to Section 264.97 (General Ground-Water Moni-
toring Requirements), the owner/operator must comply
with the following requirements for any ground-water
monitoring program developed to satisfy §264.98, §264.99,
or §264.100:
(a) The ground-water monitoring system must consist of a
sufficient number of wells, installed at appropriate
locations and depths to yield ground-water samples from
the uppermost aquifer that:
(1) Represent the quality of background water that has
not been affected by leakage from a regulated unit;
and
(2) Represent the quality of ground water passing the
point of compliance.
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(g) Where appropriate, the ground-water monitoring
program must establish background ground-water
quality for each of the hazardous constituents
or monitoring parameters or constituents specified
in the permit.
(1) In the detection monitoring program under §264.98,
background ground-water quality for a monitoring
parameter or constituent must be based on data from
quarterly sampling of wells upgradient from the
waste management area for one year.
(2) In the compliance monitoring program under §264.99,
background ground-water quality for a hazardous
constituent must be based on data from upgradient
wells that:
(i) Is available before the permit is issued;
(ii) Accounts for measurement errors in sampling and
analysis;
(iii) Accounts, to the extent feasible, for seasonal
fluctuations in background ground-water quality
if such fluctuations are expected to affect the
concentration of the hazardous constituent.
(3) Background quality may be based on sampling of
wells that are not upgradient from the waste manage-
ment area where:
(i) Hydrogeologic conditions do not allow the owner or
operator to determine what wells are upgradient; or
(ii) Sampling at other wells will provide an indication
of background ground-water quality that is as repre-
3-11
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sentative or more representative than that provided
by the upgradient wells.
In summary, the monitoring well system must yield ground-
water samples from the uppermost aquifer that represent both
the quality of background water as per Section 264.97 (a)(l)
and the quality of ground water passing the point of compli-
ance as per Section 264.97 (a)(2). Background wells are
preferably located upgradient but are not required to be
upgradient under special circumstances as outlined in Section
2.3. Where Section 264.92 and Subsections 264.97 (a)(l) and
(a)(2) cannot be met, a permit can be denied. An inability
to install wells at sites around the waste management area
that satisfy the criteria is one such situation that is
grounds for permit denial.
Further provisions of Subpart F and permit information
requirements of 40 CFR Part 270.14(c) require the owner/
operator to "determine the ground-water flow rate and direc-
tion in the uppermost aquifer." Both the detection monitoring
program (Part 264.98(e)) and the compliance monitoring program
(Part 264.99(e)) specify the following:
(e) The owner/operator must determine the ground-water
flow rate and direction in the uppermost aquifer at
least annually.
The same provision applies to monitoring of corrective actions
under Part 264.100(d). 40 CFR Part 270.14(c)(2) requires the
owner/operator to do the following:
(2) Identify the uppermost aquifer and aquifers
hydraulically interconnected beneath the facility
3-12
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property, including ground-water flow direction
and rate, and the basis for such identification
(i.e., the information obtained from hydrogeologic
investigations of the facility area).
Where the ground-water flow rate and direction is not identi-
fied and the owner/operator cannot correct the deficiency
in the permit application after being served a notice to
to this effect, a permit can be denied on the grounds that
monitoring standards cited above cannot be met. Furthermore,
a basis for permit denial exists in cases where hydrogeologic
conditions at the facility location are so complex that a
determination of ground-water flow direction and flow rate
are not possible (for example, karst terrains or fractured
bedrock).
Certain existing HWLSD facilities may be exempt from
ground-water monitoring requirements as set forth in 40 CFR
Part 264.90.
3.2.2 Liner Foundation Requirements
Design and operating standards for waste piles, landfills,
and surface impoundments require a liner (see Parts 264.251(a),
264.301(a), and 264.221(a), respectively) that is designed,
constructed, and installed to prevent any migration of waste
out of the unit to the adjacent subsurface soil, ground water,
or surface water at any time during the active life (including
the closure period) of the facility. Liner foundation require-
ments are identical for each type of unit. Existing portions
(.
of existing facilities are exempt from the liner standard.
The standard includes the following element:
3-13
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The liner must be placed upon a foundation or base
capable of providing support to the liner and
resistance to pressure gradients above and below the
liner to prevent failure of the liner due; to settlement,
compression, or uplift. (see Section 264.221(a)(2)
(surface impoundment), Section 264.251(a)(1)(ii) (waste
piles), and Section 264.301(a)(1)(ii) (landfills)).
The following sensitive areas will generally possess
hydrologic, geologic, and pedologic characteristics that
may create conditions at the facility site that could result
in an inability to comply with the liner foundation standard:
0 landslide-susceptible areas
0 subsidence-prone areas
0 karst terrains
0 weak and unstable soils
The permit writer should require the applicant to submit
a geotechnical engineering report that demonstrates compliance
with the liner foundation requirement and demonstrates, based
on the history of the location's stability, the likelihood of
impacts at the site due to mass movement, subsidence, and weak
soils. The report requirement is included under the general
ground-water information gathering authority in 40 CFR Part
270.14(c) plus the authority for specific units under 40 CFR
Part 270.17(b) (surface impoundments), 40 CFR Part 270.19(c)
(waste piles), and 40 CFR Part 270.2Kb) (landfills).
The permit writer's case for permit denial may not be
based on a notion that a mere possibility of unstable
foundation conditions exist at the site or may exist at the
site in the future. If a facility is located in an area
3-14
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where subsidence is actually occurring, the applicant must
demonstrate that engineering efforts to improve the foundation
of the liner will ensure compliance with the standard. Where
there is a sound likelihood of a future landslide or subsi-
dence event, the applicant must demonstrate how the proposed
design will prevent failure in the event of a landslide or
subsidence. The permit writer must critically evaluate
these demonstrations, seeking expert assistance as necessary,
before permit issuance. If the demonstration shows that condi-
tions at the site are not adequate for the installation of
the liner, the permit must be denied.
3.2.3 Closure Standards
At closure, owner/operators of landfills and surface
impoundments, where waste is not to be removed or decontami-
nated, are required to cover the unit with a final cover
designed and constructed to:
(1) provide long-term minimization of migration of
liquids through the closed unit,
(2) function with minimum maintenance,
(3) promote drainage and minimize erosion or abrasion
of the cover,
(4) accommodate settling and subsidence so that the
integrity of the cover is maintained, and
(5) have a permeability less than or equal to the
permeability of any bottom liner system or natural
subsoils present.
(see Section 264.310(a) (landfills) and Section 264.228(a)
(2)(iii) for surface impoundments)).
The closure standards apply to all units used for disposal
independent of the requirements under the liner foundation
3-15
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standards (see Section 3.2.2).
High hazard and unstable terrains may be subject to
forces and natural events that pose conditions where cover
failure and escape of hazardous waste to ground or surface
waters or the atmosphere from a unit are likely to occur in
these locations during the post closure period, as well as
the active life of the facility. Facilities proposed or
located in high hazard and unstable terrains may be subject
to local hydrogeologic conditions that could make compliance
with the closure standard difficult. Permits for new facil-
ities, expansion of existing units, and existing facilities
should be denied when an owner/operator cannot demonstrate
an ability to comply with RCRA performance standards.
The applicant must submit an engineering report that
provides the following: (a) a description of how the cover
standards will be complied with, (b) a site characterization
that delineates the specific site and local conditions that
create high hazard and unstable conditions, and (c) the
probability that the facility will be impacted by such
conditions. The permit writer is authorized to require this
report through Section 270.17(g) for surface impoundments
and Section 270.21(e) for landfills. In submitting this
report, the permit applicant must demonstrate how the pro-
posed closure design will prevent the migration of waste
from the unit. The permit writer must critically evaluate
this demonstration, seeking expert assistance as necessary,
before permit issuance. If the demonstration is not adequate,
the proposed closure design should not be approved.
3-16
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3.2.4 Dike Integrity Standard
Although the dike integrity requirement applies to all
surface impoundments used to treat, store, or dispose of
hazardous waste, the requirement is particularly important
in the case of existing storage impoundments because neither
liner nor cover standards apply to these units.
The design and operating requirements for surface impound-
ments specify the following:
A surface impoundment must have dikes that are designed,
constructed, and maintained with sufficient structural
integrity to prevent massive failure of the dikes. In
ensuring structural integrity, it must not be presumed
that the liner system will function without leakage
during the active life of the unit.
(See 40 CFR Part 264.221(d)).
High hazard and unstable terrains are subject to forces and
natural events that may impair the structural integrity of
dikes. Seismic ground motion due to earthquakes or volcanic
activity combined with weak soil conditions in landslide-
prone locations are "worst case1 scenarios. A permit should
be denied if the dike system cannot provide an adequate
factor of safety under various conditions that exist or are
likely to occur in these sensitive locations. For example,
dikes must be safe and stable during all phases of construc-
tion and operation of a surface impoundment. Of particular
interest is the stability of the dike to preclude failures
during (1) the end of construction, (2) steady-state seepage,
(3) rapid drawdown, and (4) seismic and volcanic events.
3-17
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Elements to be considered in the design and evaluation of
dikes for stability and addressed in the application include
foundation conditions, embankment materials, and liner type,
all of which are part of the dike system.
Foundations may present problems where they contain
adversely oriented joints, slickensided or fissured material,
faults, seams of soft materials, or weak layers. Liquefaction
of loose, saturated sands and silts may occur under conditions
of cyclic to shear deformation by earthquake shocks (or nearby
heavy construction activity).
Slope failure of the dike system, in which a portion of
the dike or of an embankment and foundation moves by sliding
or rotating relative to the remainder of the mass, is the
major consideration in stability analyses. Minimum factors
of safety should be reported from slope stability analyses
conducted for the following failure modes:
0 End of construction (proposed dikes only)
0 Steady-state seepage
o
0 Seismic conditions (when in a sensitive area that is
Rapid drawdown
rated as earthquake-prone; see zones 2 and 3 in Figure
2.2.2-1 on Seismic Zoning in the United States)
No single, specific, minimum Factor of Safety for slope
stability has been recommended. An acceptable Factor of
Safety depends on the confidence with which soil data are
known and the consequences of a dike failure. (see Section
5.2.4 on "Structural Integrity of Dikes" in the Permit Appli-
cants' Guidance Manual for Hazardous Waste Land Treatment,
Storage, and Disposal Facilities, Final Draft, May 1984 (EPA
530-SW-84-OU4). This manual is available for $13.00 from
3-18
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the Government Printing Office (GPO) under stock number
055-000-00240-1 by calling GPO at (202)783-3238).
3.3 SUPPLEMENTAL REGULATORY PROVISIONS FOR PERMIT APPROVAL
Permits for hazardous waste land storage and disposal
(HWLSD) facilities proposed or sited in unacceptable locations
can include supplemental conditions under RCRA rules as
additional safeguards to compensate for location limitations.
Table 3.3-1 lists the applicability of various supplemental
RCRA provisions to each of the criteria for location accepta-
bility. Permit writers should investigate the feasibility of
using supplemental provisions for facility locations where a
permit denial based on the requirements presented in Section
3.2 is inappropriate. Supplemental provisions may be used
in order to account for the added risk of an unacceptable
location. Supplemental provisions are as follows:
0 restricting considerations of alternate concentration
limits (ACLs) in post-closure permits and of exclu-
sions of Appendix VIII constituents from monitoring,
0 requiring contingent corrective action programs,
0 extending the post-closure care period.
3.3.1 Alternate Concentration Limit (ACL) and Appendix VIII
Exclusion Restrictions
Regional Administrators are authorized to establish an
alternate concentration limit (ACL) for hazardous constituents
in the ground-water protection standard (40 CFR Part 264.94(b)).
In establishing the ACL, the Regional Administrator must
consider a number of factors including:
(1) Potential adverse effects on ground-water quality,
considering the following: <.
(ii) The hydrogeologic characteristics of the facility
and surrounding land;
3-19
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(iii) The quantity of ground water and the direction of
ground-water flow;
(iv) The proximity and withdrawal rates of ground-water
users;
(v) The current and potential usages of ground water
in the area;
(vi) The existing quality of ground water, including
other sources of contamination and their cumulative
impact on the ground-water quality.
(2) Potential adverse effects on hydraulically-connected
surface-water quality, considering the following:
(ii) The hydrogeologic characteristics of the facility
and surrounding land;
(iii) The quantity and quality of ground water, and
the direction of ground-water flow as it affects
surface waters;
(iv) The patterns of rainfall in the region;
(v) The proximity of the regulated unit to surface
waters;
(vi) The current and potential usages of surface
waters in the area and any water quality standards
established for those surface waters;
(vii) The existing quality of surface water, including
other sources of contamination and the cumulative
impact on surface-water quality.
(viii) The potential damage to wildlife, crops, vegetation,
and physical structures caused by exposure to waste
const ituents.
The Regional Administrator must also consider "any identifica-
tion of underground sources of drinking water and exempted
aquifers made under §144.8 of this chapter" in making a
decision regarding the use of ground water in the area around
the facility (see Part 264.94(c)).
HWLSD facilities that do not meet the design, operation,
and location standards where the first four criteria for
location acceptability are factors in their noncompliance
3-21
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should not be issued operating permits under existing RCRA
regulations. These facilities must close any existing
regulated units and obtain a post-closure permit that applies
the Part 264 Subpart F Standards. It is unlikely that the
issuance of ACLs would be appropriate at these facilities
because it would already have been demonstrated that the
facility location presents problems that inhibit a favorable
demonstration under the factors listed in §264.94(b).
Facilities located above Class I ground water and above
Class II ground water in vulnerable locations may pose a
distinct threat to the ground-water quality as well as to
hydraulically-connected surface-water quality. The Agency
may consider changes to the current RCRA standards which
would eliminate the opportunity to make ACL demonstrations
for facilities in these locations.
The Regional Administrator may specify the hazardous
constituents to which the ground-water protection standard
under Part 264.92 applies in a particular facility permit.
Constituents to be monitored are to be selected from the
list in Appendix VIII of Part 264. The Regional Administrator
may exclude an Appendix VIII constituent from the list of
hazardous constituents specified in the permit if the
applicant can demonstrate that the constituent is not capable
of posing a substantial present or potential hazard to human
health or the environment (see 40 CFR Section 264.93(b)).
In deciding whether to grant a monitoring exemption for a
hazardous constituent, the Regional Administrator must
consider the same factors as are required to grant an ACL
3-22
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(see Section 3.3.1). Existing HWLSD facilities that are
sited in locations that do not meet one or more of the criteria
for an acceptable location will, in many cases, fail to qualify
for an exclusion of Appendix VIII constituents. Facilities
located in vulnerable settings above Class I or Class II
ground water especially, pose a distinct threat to ground-
-water quality and to hydraulically-connected surface-water
quality. Regional Administrators should consider carefully
the use of an exclusion of Appendix VIII constituents from
monitoring requirements at facilities sited in locations
that do not meet all criteria of acceptability outlined in
the Location Guidance Manual.
3.3.2 Combined Ground-Water Protection Programs in RCRA Permits
Provisions in the ground-water protection standard under
40 CFR Section 264.91(b) authorize Regional Administrators
to combine more than one ground-water protection program in
a facility permit. The Regional Administrator may combine
detection monitoring, compliance monitoring, and/or corrective
action programs as part of the facility permit application
as necessary to protect human health and the environment.
In deciding whether to invoke this authority, the permit
writer should consider the potential adverse effects on
human health and the environment which might occur during
the administrative period necessary to revise the permit to
establish a different ground-water protection program.
Existing facilities sited in areas where the local hydrologic
and geologic setting creates a sensitive location present
appropriate circumstances for requiring a combined program.
3-23
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Requiring a contingent corrective action program, for example,
will eliminate the added time needed for administrative
processing and permit modification preparation prior to
implementation of corrective action. In this way, timely
corrective action is better assured when a fcacility failure
occurs. The difficulty with this approach is that the Agency
cannot require the applicant to submit the information necessary
for a contingent corrective action program unless there has been
a release of a hazardous constituent in excess of ground-water
protection standards (see 40 CFR § 270(14)(c)(8)). The permit
writer can gather the necessary information independently of
the permit application process using other information gathering
authorities such as Sections 3007 and 3013.
Assuming that the necessary information can be obtained and
permit denial is not appropriate, the permit writer should consider
requiring contingent corrective action plans in the permit at
existing HWLSD facilities located in a sensitive area or in
vulnerable settings above Class I or Class II ground water.
The failure of a facility due to a likely natural or man-induced
event in a sensitive location, or the rapid migration of contam-
inants following a failure event in a vulnerable setting over
Class I and II ground waters will generally require immediate
corrective action to protect human health and the environment.
Combining corrective action provisions with detection
and/or compliance monitoring programs may be difficult. In many
cases, it may not be possible to include a full, comprehensive
corrective action plan in a permit due to the complexity of
site-specific hydrogeologic characteristics. However, when the
3-24
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situation warrants, it may be possible to develop an interim
program which would include general steps to be taken to protect
human health and the environment, and which would require the
collection of additional information on the specific remedy
needed. The new information acquired pursuant to this interim
program would then provide the basis for a permit modification
(pursuant to §270.41 (a)(2)) to establish a more detailed
corrective action program.
Special attention should be taken to assure that the
corrective action proposed by the permit applicant is appropriate
for the unstable conditions that exist at each sensitive
location. The permit writer should be convinced that the
corrective action will work to prevent additional adverse
impacts that may result due to local hydrogeologic conditions.
The permit writer may require a simulation using a numerical
or analytical model calibrated to specific site conditions.
The permit writer should consider requiring a combined ground-water
protection program for existing facilities that seek a
permit to operate in certain sensitive locations (assuming
that permit denial has been determined to be inappropriate).
The Agency may change the current RCRA standards to strengthen
the combined permit approach.
3.3.3 Extended Post-Closure Care Period
Facility post-closure care must continue for thirty
years after the date of completing closure as specified in
40 CFR Part 264.117. The Regional Administrator may "extend
the post-closure care period if he or she finds that the
extended period is necessary to protect human health and the
3-25
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environment" (see 40 CFR Section 264.117(a)(2)(ii) ) . Exist-
ing land disposal facilities located in sensitive areas
where containment structures are likely to fail or in vulner-
able settings above Class I or Class II ground water may
require an extension of the post-closure period to prevent
significant adverse impacts from occurring when the facility
fails. The permit writer may be able to determine an appro-
priate timeframe over which the post-closure care period
should be extended based upon site hydrologic and geologic
conditions. The ability of the location to prevent rapid
waste migration when failure occurs may play a part in deter-
mining an appropriate closure period extension. The Phase
II location guidance will provide the permit writer with
various methods for making a determination.
In certain cases, ultimate removal of waste at closure
for existing land disposal units sited in either high hazard
and unstable terrains or in vulnerable settings above Class
I or Class II ground water may be the only viable alternative
in preventing adverse impacts from occurring during the
post-closure period. Facility owner/operators having land
disposal units in these locations may eventually need to
remove waste at closure.
3-26
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3.4 CONSIDERATIONS UNDER THE IMMINENT HAZARD PROVISION OF RCRA
AND OTHER PROVISIONS OF THE RCRA AMENDMENTS OF 1984
Section 7003 of RCRA provides, in part that:
"Notwithstanding any other provision of
this Act, upon receipt of evidence that
the handling, storage, treatment,
transportation or disposal of any solid
waste or hazardous waste may present an
imminent and substantial endangerment to
health or the environment, the Adminis-
trator may bring suit on behalf of the
United States in the appropriate district
court to immediately restrain any person
contributing to such handling, storage,
treatment, transportation or disposal to
stop such handling, storage, treatment,
transportation, or disposal or to take
such other action as may be necessary...."
This provision gives EPA broad authority to issue adminis-
trative orders in any situation where the presence of solid
waste or hazardous waste may present an imminent and substantial
endangerment to health or the environment. The terms "imminent
and substantial endangerment" as used in this Section have been
judicially defined several times to mean that evidence of actual
harm is not required, but only the risk of harm.
One must judge the risk or likelihood of the harm by examining
the factual circumstances, including, but not limited to: 1)
nature and amount of the hazardous substance; 2) the potential
for exposure of humans or the environment to the substance; and
3) the known or suspected effect of the substance on humans or
that part of the environment subject to exposure to the substance.
Guidance on the applicability and use of §7003 Administrative
Orders has been distributed by the Office of Enforcement and
Compliance Monitoring (OECM). The OECM guidance is a revision
of a September, 1981 Agency document issued by the Office of
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Waste Programs Enforcement. The following discussion is intended
to supplement the OECM guidance on §7003, and not to be read in
lieu of it. Use of Section 7003 authority and various other
authorities under the RCRA amendments of 1984 may be appropriate
under several situations encountered in evaluating permit applications
under Part 264 and associated location considerations. The
concepts presented in this section of the Phase I manual represent
situations that may be unique to permit application evaluation
and the location criteria.
3.4.1 Considerations Prior to Permit Issuance
Under the 1984 RCRA amendments, the Agency has new authority
in Section 3008(h) (Interim Status Corrective Action Orders)
that may be more appropriate than the current imminent hazard
provision when imminent and substantial endangerment is identified
at an interim status RCRA facility. This authority is extremely
broad and enables the Agency to initiate a corrective action program
upon detection of a release of a hazardous waste or hazardous waste
constituent from a solid waste management unit. Additional
guidance will be forthcoming in early 1985 on various situations
and conditions when each of the several authorities now offered
to the permit writer are most appropriate.
Situations that may pose an imminent and substantial endanger-
ment that could be discovered during permit application evaluation
include the following:
1) An aspect of an existing facility design or operation
provides an inadequate factor of safety, and there is
a risk of massive failure.
In particular, if a surface impoundment dike has a
factor of safety, under steady state conditions, of less
3-28
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than or equal to 1 .3, an imminent hazard may exist. A simi-
lar factor of safety under a rapid drawdown analysis poses
an imminent hazard if there is any reason to anticipate a
complete or substantial emptying of the impoundment prior to
permit issuance. Similarly, if it can be shown that the
mass of the waste management unit (i.e., waste pile, land-
fill, impoundment) is unstable, due to weak foundation soils
or landslide potential, an imminent hazard may exist.
The potential for such problems to exist may be greater
at locations described as high hazard and unstable terrains
(see Section 2 .2) than in other areas. When evaluating
permit applications for facilities -located in such terrains,
the permit writer should always determine if an imminent
hazard exists. Imminent hazards can exist in areas that are
not considered to be high hazard and unstable terrains,
however. In these circumstances, there may be a design or
operation problem unrelated to a location limitation, such
as inadequate dike compaction or resistance to erosion due
to piping.
2) An aspect of the hydrogeologic character of the
location, combined with a known leachate discharge, poses an
imminent hazard to off-site ground-water or surface-water
quality.
In this situation, there is no risk of massive physical
failure or collapse of the facility. Rather, existing
information indicates that there is or has been an ongoing
or prior leachate release that may pose an imminent hazard to
3 -29
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off-site ground or surface waters. This situation may occur
at locations that fail the 'Ability to Monitor1 and 'Ground-
Water Vulnerability1 criteria (see Sections 2.3 and 2.5,
respectively). In these cases, the Administrator may issue
an order under Section 3008(h) requiring corrective action
or such other response measure as he or she deems necessary
to protect human health or the environment.
3.4.2 Considerations After Permit Issuance
The permit writer may determine that no imminent hazard
exists prior to the time that the permit is issued, and that
problems related to location can be satisfactorily addressed
by permit conditions. If a permitted facility is in a
setting that does not satisfy the location criteria listed
in Section 2.0 of this manual, the permit writer should
provide special tracking of permit compliance to ensure that
an imminent hazard related to a location problem does not
develop. This special tracking to ensure that the permit is
in compliance should be planned through consultation between
the permit writer and the Regional Office section responsible
for facility inspections. State Agency personnel should be
involved in the tracking to the extent that: State Authoriza-
tion or cooperative arrangements make it appropriate.
Under the new authority offered by Section 3004(u) of RCRA
(Continued Release at Permitted Facilities), where a release of a
hazardous waste or constituents is occurring from any solid waste
management unit at a treatment, storage, or disposal facility,
-------
the Administrator may require a corrective action at a permitted
facility to alleviate any hazard to public health and the
environment. The use of this authority rather than the
authority afforded by Section 7003, would be more appropriate
in the case where a hazardous waste or constituent release
is occurring at the facility.
3-31
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4.0 CASE STUDIES FOR ANALYZING LOCATION CRITERIA AND EXISTING
APPLICABLE REGULATIONS
Four case studies based on actual RCRA Part B permit
applications have been summarized to demonstrate how a
permit writer should evaluate whether a location meets the
criteria for an acceptable location. Only those criteria
having a regulatory or statutory basis are evaluated at this
time. Methods for evaluating the ground-water vulnerability
criterion are reserved for the Phase II location guidance
manual currently being developed. A more complete evaluation
of each location highlighted in this section, as well as
additional case studies in other locational settings, will be
presented in an Appendix to the Phase II guidance manual.
Sixty six permit applications were reviewed during
the fall of 1983 for information and data availability and
completeness. Locations of facilities were sorted according
to physiographic province and hydrogeologic setting. Two
general classification systems were used in the sorting
process. These systems are A.L. Charles Hunt's physiographic
regions of the United States and Canada (1974) shown in
Figure 4.0-1 and Ralph Heath's ground-water regions of the
United States (1984) shown in Figure 4.0-2. The permit
applications selected for case study represent a wide variety
of locational settings appropriate for applying each of the
criteria for an acceptable location. Table 4.0-1 lists the
case study location, physiographic province, and ground-
c
water region. Table 4.0-2 summarizes facility types,
applicable location acceptance criteria evaluated, and permit
4-1
-------
action recommended for each of the four case studies discussed,
Each case study has a three-section format: (1) loca-
tional setting description, (2) hydrogeologic analysis, and
(3) recommended permit action based on the first four location
acceptance criteria. Information contained in the location
setting description was taken directly from the Part B permit
application. Editorial discretion was used to reduce text
length and avoid redundance. The identity of the facility
permit applicant and various consultants hired on behalf of
the applicant have been omitted.
All facility owner/operators whose Part B permit
applications were used in the case study evaluations were
sent notices of deficiencies. Although certain sections of
the application were complete, site characterization and
related hydrogeologic information was not always complete.
Additional information submitted to the Agency subsequent to
the preparation of this manual could influence the location
evaluation to some extent. For this reason, all case studies
will eventually be supplemented with additional information
that may have been received by permit writers in response to
deficiency notices.
The location evaluation and comment presented in this
section are currently under further study. Any position
taken regarding case study facilities should not be
interpreted as an official Agency decision for permit action.
4-2
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Baffin Upland
Mountain
Plateaus
Plains
A Canada West of Mackenzie River
B Pacific Mountain System, includes
C Pacific Border
D Lower California
E Columbia-Snake River Plateau
F Thelon Plains and Back River Lowland
G Athabasca Plain
H Wyoming Basin
I Ouachita
J Ozark Plateaus
K Interior Low Plateaus
L Appalachian Plateaus
M Valley and Ridge
N Adirondack
0 St. Lawrence Lowland
P Blue Ridge
Q Piedmont Plateau
FIGURE 4.0-1:
Physiographic regions of the United States and Canada and their dominant landforms. About one-
quarter o/ the land is mountains, one-quarter pjateaus, and about half plains.
4-3
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The following subsections summarize the locational
setting and evaluation for each case study.
4.1 CASE STUDY A
Location: Far Western United States
Type of Facility: Landfills and surface impoundments
Physiographic Setting: Bay mud
The facility totals approximately 535 acres, and is
divided into a north and south parcel. The north parcel
contains an existing 125-acre sanitary landfill used for the
disposal of hazardous waste and a 20-acre surface impoundment
previously used for the disposal of hazardous waste.
The owner has proposed to extend the north parcel landfill
onto virgin marsh bay muds adjacent to the current landfill.
Nearby land uses are primarily of industrial character (petro-
leum chemical storage tanks) with limited residential use.
Test borings in this area indicate that the entire north
parcel is underlain by weak, compressible, peaty and silty
marsh deposits of low permeability known as bay mud. The
bay mud varies in thickness from 4 to 62 feet and is under-
lain by relatively incompressible, moderately strong silts
and clays of low permeability. In turn, these sediments are
underlain by moderately hard to fractured sandstone and shale
formations (see the site plan and geologic cross-sections in
Figures 4.1-1 through 4.1-4).
Laboratory tests performed on the bay mud indicate that
vertical permeabilities range between 1.8 x 10~6 and 3.0 x
10~7 cm/sec. Slug testing showed the horizontal permeability
to range between 5.2 x 10~^ and 1.9 x 10~^ cm/sec.
Enforcement actions were taken to require the repair of
4-7
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leaks in surface impoundment dikes at the facility.
4.1.1. Summary of Locational Evaluation
0 The facility is within the 100-year flood/tide zone
of a local creek. The facility is also to be sited
in an area described as "marsh" and, therefore, may
be in a wetland as defined in Section 404 of the
Clean Water Act.
0 The facility is suspected to overlie an active fault,
but no direct evidence was presented in the applica-
tion to conclusively support this assertion.
0 The facility will be subject to ground motion during
seismic activity and may be impacted by numerous
active faults in the proximity of the site. As a
result of this ground motion the facility is expected
to experience permanent displacement of landfill
slopes and further displacements due; to creeping of
the marsh soils. These displacements may threaten
the integrity of the landfill and caps. Continuous
maintenance of the engineered containment structure
will likely be required.
0 The facility is expected to settle into the bay mud
up to one quarter of its design thickness within
thirty years of facility closure. The permit appli-
cation does not state if further settle will occur
after thirty years but additional settlement seems
likely. Settlement of this magnitude will threaten
the integrity of the landfill cap and liner and
require continuous maintenance.
0 As a result of an expected rise in sea level, the
elevation of the 100-year flood may also rise above
protecting dikes and expose the facility to wash out
within the predictable future. This rise may occur
prior to closure.
0 The uppermost aquifer is the bay mud deposit with bay
mud water table elevations at the land surface. The
bay mud is relatively impermeable vertically (1 x
10~6 cm/sec) but is one to two orders of magnitude
more permeable horizontally.
Information concerning ground-water flow gradients
was not supplied.
The principle ground-water flow pathways for
pollutant migration are horizontal flow in the
bay mud with discharge to a nearby creek. Time of
travel for 100 feet horizontally in bay muds was
calculated to be 15.2 years. Waste escaping the
4-8
-------
facility and discharging into the creek will be
diluted to an unknown extent, possibly below safe
levels.
4.1.2 Discussion of Location Issues
At facility A, the permit writer determined that the location
fails all of the location acceptance criteria and is, therefore,
an unacceptable location. The evidence of bay mud instability
under the landfill load and during seismic events indicates an
unstable geologic environment that will require perpetual
monitoring and maintenance of engineered containment structures.
The threat of instability is compounded by the prospect of
sea level rise in the near future.
The permit applicant does not address key elements of a
characterization such as the presence of wetlands, ground-
water flow gradients, and sea level rise. The uppermost aquifer
was incorrectly identified. Based on available information
regarding the site hydrology, it appears that constituents
escaping the facility may move rapidly offsite, possible to a
creek near the site.
A mitigating factor that must be considered at this
location is the attenuative capacity of the bay mud. The
bay mud possesses a high content of organic carbon and clay
minerals. Although these materials are known to attenuate
selected hazardous constituents, the exact level of attenuation
cannot be predicted and is constituent specific. No documentation
of attenuative capacity was presented in the permit application.
4-9
-------
I I A'-' \% /'// . 4w
Jl -V^1 y.// f :^f-
k^ .x\v •'//- /?//«r
r • v a < T • •'•*-• v
4-10
-------
FIGURE 4.1-2
CASE STUDY A: LOCATION OF CROSS SECTIONS
4-11
-------
ELEVATION
MSL
+1001
Debris Fill
Bay Mud with Varying Amounts of Peat
"Bay Mud
Clayey Sand! and Stiff Silts and Clays
ELEVATION
MSL
•MOO-,
100-1
SECTION I-I
Bay^Mud_with^arying Amounts of Peat _"~
" Bay Mud
Clayey Sands and Stiff Silts and Clays
SECTION n-n
Note: Sec Plate C1 for Location of Cross Sections
FIGURE 4.1-3
CASE STUDY A: SECTIONS I-I' AND II-II1
4-12
-------
+100 -i
<
UJ
-100
Dabris Fill
Bay Mud witjwarying Amount* of Peat
Bay Mud
Clayay Sands and Stiff Silts and Clays
SECTION m- in'
CREEK
+100 i
-100 J
Bay Mud with Varying Amount! of P««t
Bay Mud
Clayey Sandi and Stiff Silts and Clays
SECTION EZ -12'
100fMt
SCALE
FIGURE 4.1-4
CASE STUDY A: SECTIONS Ill-Ill1 AND IV-IV
4-13
-------
4.2 CASE STUDY B
Location: Northeastern United States
Facility Type: Surface impoundments, waste pile
Physiographic Province: Appalachian Mountains
Located on a 200 acre site, the facility consists of a
waste treatment operation, three liquid waste holding tanks,
a prepared surface for solid waste holding, a surface impound-
ment for holding recycled water (SI-4), and a surface impound-
ment for disposal (SI-5). In addition, the site also contains
three abandoned surface impoundments which were previously
utilized for ultimate disposal.
The local geology is complex and cannot be easily
summarized. Several maps and geologic cross-sections were
prepared by the applicant and are included in Figures 4.2-1
through 4.2-5. Dipping, nonfolded strata of sedimentary rock
are covered by a layer of alluvium and fill. Coal seams have
been surface mined and subsurface mined on the site.
It is difficult if not impossible to determine all
potential ground-water flow paths that exist, beneath this
facility. One flow path not discussed by the applicant is
within the alluvium and fill, flowing toward a minor
tributary adjacent to Impoundment 4 (SI-4). An examination of
topographic surface contours shows that Impoundment 5 (SI-5)
was built within a branch of the unnamed tributary. Gradients
beneath the surface impoundments will be large in the event
of liner failure due to 35 feet or more of static hydraulic
head in the impoundments. More hydrogeologic information is
required to completely assess the potential for flow in the
alluvium and surface soils.
4-14
-------
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4-15
-------
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4-16
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4-18
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Flow paths into the Pittsburgh Sandstone and lower
lithologic units, including the Pittsburgh Coal and Pitts-
burgh Limestone, are very difficult to predict. Normally,
recharge of ground water into dipping layers such as these
occurs in the limited area where the strata outcrops; in
this case, east and upgradient from the surface impoundments
and waste pile. However, vertical fractures in the
Pittsburgh Sandstone present a cross-strata flow path.
These fractures are likely a result of subsidence due to
mining of the Pittsburgh Coal. Should leachate leaking from
the units reach the coal and limestone strata, contaminants
would migrate with the regional flow toward the west and
downdip. This flow path is complicated by the numerous mine
tunnels within the Pittsburgh coal seam. Several borings
(TB-6, TB-7, and TB-8) indicate mine tunnel voids
20 feet to 92 feet from the surface directly under the impound-
ments. In addition, the state has documented that two abandoned
mine tunnels are located from 40 to 90 feet below the base
of the surface impoundment dike. Predicting flow in these mine
tunnels is impossible based on data in the permit
application. It appears likely that leachate reaching the
Pittsburgh Coal seam would reach a mine tunnel. It is also
possible that during the construction of Impoundment 5,
flow paths to a shallow mine tunnel were created.
4.2.1 Summary of Locational Evaluation
0 The permit application does not contain information
which would indicate that the facility is located on
protected lands.
4-20
-------
0 Surface Impoundment 5 was built in a former stream
channel receiving surface water from a watershed of
approximately 425 acres.
0 The potential for subsidence due to mine tunnel
collapse was not addressed by the applicant. The
prevalence of mine tunnel voids may result in
subsidence that may eventually cause liner foundation
failure and cover subsidence. The facility is located
in a high hazard and unstable terrain.
0 Flow paths beneath the facility are difficult to
predict. The hydrogeology is complex due to dipping
strata, alluvium, and both surface and subsurface
mining. Information on water tables in the alluvium
and the hydraulic properties of the alluvium are not
provided in the application. Further information
regarding flow paths and additional technical review
should be conducted regarding the hydrogeology of the
site.
0 Landowners with wells located adjacent to the facility
pump drinking water from seeps that may be recharged
with ground water beneath the site of the facility.
4.2.2 Discussion of Location Issues
Given the lack of essential information and the hydrogeo-
logic complexity of the location, this site was classified
as unacceptable for the land disposal of hazardous waste since
it would not meet the criteria for site characterization and
ability to monitor ground water. In the event of facility
failure, leaking waste would migrate along unpredictable
flow paths that the owner/operator could not monitor for
ground-water quality data. Corrective action would also be
inhibited.
4.3 CASE STUDY C
Location: Interior Western United States
Type of Facility: Landfill
Physiographic Province: Basin and Range
The facility is located in a desert environment and
covers approximately 80 acres. Waste disposed in the
4-21
-------
landfill includes inorganic acids, oxidizers and bases, pes-
ticides, cyanides, metals and metallic salts, and solvents,.
Except for 'de minimus' quantities of liquids contained in
lab packs, no liquids are presently being deposed in the
landfill.
Bedrock units at the site are identified as metamorphic
rock covered by unconsolidated or weakly-cemented Quaternary
alluvial materials. These alluvial or valley-fill deposits
have been shown by drilling records to be at least 570 feet
thick beneath the site. The valley-fill deposits are silts,
sands, gravels, and cobbles of local origin, composed primari-
ly of volcanic rock, which have been transported to the site
by a combination of gravity and water transport. No distinct
boundary exists between the bajada or alluvia.! fan deposits
and desert flat deposits. The bajada deposits in this area
are primarily coarse grained, becoming finer with increased
distance from the mountain front. Desert flat materials are
a combination of fine-to coarse-grained materials laid down
at the lower ends of alluvial fans and in alluvial deposits
of valley streams, and generally fine-grained materials
deposited in basinal lakes. As a result of variable-source
areas and depositional mechanisms, bajada-desert flat deposits
are typically anisotropic and are unsaturated to depths of
approximately 300 feet.
Individual beds of materials at the site are not
continuous due to the depositional environment and finer
grained horizons cannot be relied upon to act as barriers to
migration (see the accompanying site plan and geologic cross-
4-22
-------
sections in Figures 4.3-1 through 4.3-6).
The applicant claims that leakage from the landfill will
not migrate to the uppermost aquifer because existing ground
water lies beneath a minimal recharge zone. The two princi-
ple pathways for leachate migration in an arid, low recharge
environment are vertically upward and vertically downward.
Some horizontal movement may occur due to depositional
mechanisms that create hydraulically anisotropic conditions.
A consultant report indicates that lateral migration has
occurred due to pre-RCRA waste activities. Under unsaturated
conditions, soil moisture moves from wet regions to dry
regions. In the low recharge environment, moisture cycles
in a vertical plane. During storm events, moisture infil-
trates into the dry subsoil and is again drawn to the soil
surface when evapotranspiration increases following a storm.
Moisture movement in the unsaturated zone is also strongly
controlled by the grain size of sediments, in which capil-
larity will cause preferential movement in finer grained
materials.
Moisture must accumulate during a moisture cycle for
ground-water recharge to occur. It was calculated that
percolation at the site would occur during only three months
over the course of the 60-year period of weather record.
4-23
-------
O
t—I
rc
Q-
CJ3
O
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4-24
-------
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o
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UJ
u
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O
UJ
z
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Z UJ
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u
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2 58
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4-25
-------
m
CO
o
73
O
CO
GO
CO
m
O
CO
ao
4-26
-------
FIGURE 4.3-4
CASE STUDY C CROSS SECTION B-B1
SOOTH
ELEV.
(FEET)
2780
2760
2740
2720
2700
>6BO
£660
2640
2620
2600
B
SILTY SAND WITH TRAVEL
AND COBBLES, XOX-CEMKNTED
B1
I..N MI.TY CHi1
S.\SD AND r.RAVKL
ITITH C'SBLSS
Uia SANOY
VKRY DENSE
SAND WITH
COBBLES,
VERY DENSE
SILT ASD
WITH GRAVE!.
VKKY i»::;sE BROWN ,V;D CKAY-
TA-; SILTY SAND WITH GRAVEL
\-:D CHBM.KS, PARTIAI.I.Y-
ry -•Ei.L-CK:»:i,T6D
- no/6
BROUN SILTY SASD AND
GRAVEL WITH OIBBI.ES
SANDY SILT
/"WITH GRAVEL
\ 0
TRENCH 10
GRAY-TM SILTY
CRWEL V1D
NON- IOPART1AI,I.Y^
CEMENTED
CRAY AND TAN
HO/6" sil.TY
•5'6-
ISO/6
150/6"
- ISO/6"
VERY DENSE GRAY-
BROWN StLTY SAND
AND GRAVEL, WITH
COBBLES, WELL-CEMENTED
VERY DENSE GRAY-
TXS SILTY SAND AND
GRAVEL WITH COBBLES,
PARTIAI.LY-CtMKHrED
MO/6*
160/11"
100/4"
l»0/5"
150/5"
• 133
• 200/3
- ZOO/4"
• 170/3"
- ISO/6"
VLRY IV «E CRAY-TAN
sii-fY SV;D A:;» UKA^EL T °*
WITH CHILES, WKI.L-<>'U.NTED
T D • 156
BROW! A'lD RED SANDY
CI.AYKY Stl.T WITH
TRAVEL .VND COBHi.ES
NORTH
ELEV
(FEET)
2760
2760
2740
2720
2700
2660
2660
2640
2620
2600
T D » 365'
- 110/6
- 142
TO* 156'
LEGEND
BOREHOLC NUMBER
STANDARD PENETRATION TEST
BLOWS/12" PENETRATION
UNLESS OTHERWISE NOTED
UNDISTURBED SAMPLE ATTEMPT
TERMINATION DEPTH
200
400
FEET
4-27
-------
FIGURE 4.3-5
CASE STUDY C CROSS SECTION C-C1
ELEV
CKT)
me
t740
tTOO
M20
25«0
JMO
Z>00
C1
• KMN tUM.T 11LT Wr CUfl-V SIITY
IANLY BM'.T.I . CGb»L£3 M ^ •T'L^I -
ELEV
(FKT)
•OCLMM «/CU»T
LE«ENO
SCRCtNtD MTCHVAL
CM ,
MtO
ISJO
4-28
-------
FIGURE 4.3-6
CASE STUDY C CROSS SECTION D-D1
SOUTH
ELEV
(FEET)
2TBO
2760
2740
2720
2700
2660
2660
2640
2620 ">'
2600
2580
2560
BR"WN CLAYEY SILtY
SAND AND CRAVKL
WITH SOME COBHI.F.S
MO'.!*
VEKY DENSE CKAY-BRfUN SILTY SANDY GRAVEL
WITH COBBLES, NON- TO PARTIALLY -CEt*NTED
VtKY DENSE CRAY-TAN SILTY
SVID AND GRAVEL WITH
SOME COBBLES, NON- TO
PARTIALLT-CEJCHUD
BROWN CLAYEY SILTY
SAND WITH GRAVEL
AND COBBLES
BROCi SWBY SILT Wl TH
CI.AY, T.IHV.I., A.ND
BK >.:•! sv:i'v CM \vi.i. ui 111
IK.rASIIV.AI. C'WHI.I'i.
BROUN SA1DY CKAVEL WITH
COMI.KS AND kH'LDKKS
IZ»/J"
VEXY DENSE
BROUN SILTY
SANII AND
CRAVKI.. NON-
CKMKNTtO
IOO/S
- ZOO/9"
too/i"
- 100/4*"
ELEV.
(FEET,
2780
2760
p..
' -Ltoo/i*
• T • T4.8'
L ZOO/2"
_L iso/r
V£RY DKNSK CKAY-TAN
»arv SAND, W.LL-CEMENItD
600
LEGEND
BORCHOUE NUMBER
h 67 STANDARD PENETRATION TEST
k ZOO/10" *-°"s/«" PENETRATION
UNLESS OTHERWISE NOTED
UNDISTURBED SAMPLE ATTEMPT
2720
2700
2680
2660,
2640
26ZO
2600
2560
2560
B T • T4 5'
TERMINATION DEPTH
• T*MS'
4-29
-------
The total amount of recharge was 1.5 inches or an average
of 0.025 inches per year. As noted earlier, recharge of
the uppermost aquifer occurs in relatively confined areas
of stream channels as mountain streams reach the foothills.
The evidence presented strongly suggests that, based
upon minimal precipitation, ground-water recharge will be
minimal. In addition, leachate generated as a result of
precipitation should also be minimal. The moisture balance
may also be inadequate however, since in arid areas of the
southwest, most precipitation events are high intensity,
short duration storms. Therefore performing a monthly water
balance is not accurate. A daily water balance is more
appropriate and at present the site owner/ operator is per-
forming these calculations.
4.3.1 Summary of Locational Evaluation
0 The facility is not within protected lands or a high
hazard and unstable terrain.
0 All evidence presented indicates that the facility is
located in an arid environment characterized by large
minimal recharge areas and limited recharge/discharge
areas. All evidence indicates that units at the
facility are positioned above a minimal recharge area.
0 The effect of evapotranspiration on infiltration
needs to be clarified. At present it appears that
the effect of evaporation is only significant for
liquids that have not migrated more than a few feet
below the land surface. Although it could be argued
that transpiration due to deep-rooted desert plants
may remove water that infiltrates, these plants have
been removed and take many years to re-establish.
0 Although the potential for groundwater recharge and
leachate generation is minimal, it must be stressed
that at this site the precipitation-induced leachate
generation was not as much of a concern as potential
leachate from old (but post-RCRA) disposal practices
in which drummed liquids were disposed of. Also,
4-30
-------
numerous old wells are located at the site; even the
thick unsaturated zone cannot preclude contaminant
migration down the well casings.
0 The discussion of the location of the site only
considered precipitation induced leachate generation
in the natural setting. Therefore the statement
concerning the low potential for leachate migration
is not appropriate since the site has disposed of
bulk liquids and has disturbed the natural environ-
ment. The potential for leachate migration (leachate
from all sources) has not been adequately addressed.
0 The possibility of lateral movement above the ground-
water surface, past the point of compliance, is a
concern at this and other sites with similar hydro-
geologic settings.
4.3.2 Discussion of Location Issues
The locational evaluation indicated that this facility
is located in a zone having a low potential for recharge.
Leachate escaping a unit is not likely to reach the uppermost
aquifer or migrate horizontally to any extent. Verification
of minimal recharge occurring at this setting will require a
simulation of the unsaturated flow regime calibrated using
site-specific information. Additional site investigation
will be required to determine the extent of lateral movement
of contaminants from pre-RCRA activities.
4.4 CASE STUDY D
Location: Southeastern United States
Type of Unit: Surface impoundment, land treatment
Physiographic Province: Gulf Coastal Plain
This facility is at a refinery that has operated since
the late 1930s. Two regulated units are used to store and
dispose API separator sludge. Both the surface impoundment
and the land treatment area are located approximately 250
feet east of a major river. Approximately 13 acres are used
for the land treatment area and a slightly smaller area is
4-31
-------
used for the surface impoundment. A review of monitoring
data collected over a period of one year indicates the
presence of arsenic in downgradient wells, selenium in all
wells, ammonia in downgradient wells, and barium, cadmium,
and lead in isolated samples. High levels of TOC were
detected in all wells but appeared higher in downgradient
wells. Although no review of the statistical analysis of
the data was performed, the use of a contaminated upgradient
well as a background well is questionable.
Most of the waste management area is situated on loosely
consolidated floodplain deposits consisting primarily of
unconsolidated clays, with some lenses of silt and sand.
These sediments were deposited in the incised erosional
channel of the river. The upper surface of the waste treat-
ment area is covered with five feet to more than 30 feet of
rubble and fill materials. The natural soil below the fill
is a 10 to 30 foot thick clay layer underlain by 10 to 60
feet of loosely consolidated, tan and gray silty clay to
sandy clayey silts, interbedded with relatively thin lenses
of clay, silt, and sand of limited lateral extent. Near the
river, the silt/clay unit is underlain by a very permeable
sand and gravel layer more than 30 feet thick. The total
thickness of the alluvial deposits at the site is not known
(see the site plan and geologic cross-sections in Figures
4.4-1 through 4.4-8).
4-32
-------
FIGURE 4.4-1
EXPLANATION
B-2 SOIL BORING LOCATION
O AND NUMBER,
DM-I S0«- BORING LOCATION
© AND NUMBER
W -I960
M « SOIL BORING LOCATION
*~a- AND NUMBER,
•1982
HAZARDOUS WASTE
FACILITIES
ftOO Tilt
CASE STUDY D: SOIL BORING LOCATION MAP
4-33
-------
FIGURE 4.4-2
EXPLANATION
DM'2l. UPGRADIENT SHALLOW
«> WELL (25-50')
DM-
DOWNGRADIENT SHALLOW
WELL (25-50')
WELL (IIO-I201)
•00 PUT
CASE STUDY FIONITORING-WELL NETOK
4-34
-------
IT]4-1*;* •*<+,#WMb.^"n-M!''ii .tVii.i.w.' -,-{ v- -L!'^^TTT^^/:A•••.
i Hi •!' i 'B i iM>rjj jjtir ^i Ji"'l.r L"'i.''""li!!' 'Jt •" '_!. J' _'L_ _ . ' '_ .-_'- JL_.—^ •f'vVi\
iSffiSW
*. .f.'U i,L/.hi^i»\'^ iOi'Uj «j*''i«jiii'iii''!i|i1' .!ii<^J!!*,ifJi,!.t.LuvIiStLlT
'/nil*;•••,»,i,,ji.^r 'IA >>«..''^ii..'•"v""ill- 'j'i:>.''y'iii:>i'-T'ij .Mi'1:' ;';ni!ii[i'.' .>I'.,IL *_™^_'>v^^»i
^^W'SS^^^N^
o
Q
1SN '133J Nl 'NOI1VA313
4-35
-------
EXPLANATION
CLAY
SILTY CLAY,
CLAYEY SILT
SILT, SAND,
GRAVEL
FILL
FIGURE 4.4-4
CASE STUDY D: GEOLOGIC SECTION B-B'
500 FEET
4-36
-------
c
WEST
c1
EAST
- 90
SILTY CLAY,
CLAYEY SILT
-50 J
SILT, SAND,
GRAVEL
FILL
«oo nrr
FIGURE 4.4-5
CASE STUDY D: GEOLOGIC SECTION C-C'
4-37
-------
SILTY CLAY,
CLAYEY SILT
-100
900 FEET
FIGURE 4.4-6
CASE STUDYD GEOLOGIC SECTION D~D'
4-38
-------
t
s"
UJ
u.
Z
§
s
SILTY CLAY,
CLAYEY SILT
SCO FEET
FIGURE 4.4-7
CASE STUDY D: GEOLOGIC SECTION E~E'
4-39
-------
F
WEST
M-4
F'
EAST
D-16
• -25-
.60-
-75-
-100-
EXPLANATION
CLAY
SILTY CLAY,
CLAYEY SILT
SILT, SAND,
GRAVEL
FILL
500 FEET
-125 J
FIGURE 4.4-8
CASE STUDY D: GEOLOGIC SECTION F-F'
4-40
-------
The upper alluvial materials contain a water table that
is hydraulically connected to the river by an underlying
aquifer. Some seasonal change in gradients is expected but
no flow reversals have been demonstrated. Permeabilities
ranged between 10"^ and 10""^ cm/sec based on field testing.
The steepest horizontal gradient was 0.017 and a vertical
gradient as steep as 0.2 was estimated.
4.4.1 Summary of Locational Evaluation
0 The facility is not within protected lands or a high
hazard and unstable terrain.
0 The uppermost aquifer is not identified. Most production
wells in the area are located over 30 0 feet deep in sandy
aquifers. Hydraulic conductivity and gradient information
is incomplete.
0 Two principle ground-water flow pathways can be identified
for potential contaminant migration. One is horizontally
west toward the river. The other is vertical toward
the lower sandy aquifers. The role of the fill material
and the underlying sand and gravel aquifer in ground-water
flow has not been studied thoroughly.
0 The flow regime appears to be relatively uncomplicated
and proper monitoring should be feasible at the site.
0 The major river system is directly downgradient.
0 The facility is located over aquifers which are used for
the water supply of a medium-sized city. Contamination
of this aquifer has not been ruled out by the above
analysis.
4.4.2 Discussion of Location Issues
Based on the information available, it was determined that
this site fits into the category of unacceptable locations principally
due to inadequate site characterization and failure to meet the
site monitoring criterion since a well network designed for
proper ground-water monitoring has not been thoroughly designed.
4-41
-------
REFERENCES
U.S. Geological Survey, 1981. Facing Geologic and Hydrologic Hazards.
Geological Survey Professional Paper 1240-8. W. W. Hays, ed.
U.S. Government Printing Office. Washington, D.C.
Mullineaux, D. R., 1976. Preliminary Overview Map of Volcanic Hazards
in the 48 Conterminous United States. U.S. Geological Survey
Miscellaneous Fiald Studies Map MF-786, Scale 1:7,500,000.
Davies, W. E., 1970. Karst Lands and Caverns. U.S. Geological Survey.
National Atlas of the United States of America. U.S. Government
Printing Office. Washington, D.C.
Bailey, R. A., P. R. Beauchemin, F. P. Kapinos, and D. W. Klick. 1983.
The Volcano Hazards Program: Objectives and Long-Range Plans.
U.S. Geological Survey. Open-File Report 83-400. Reston, VA.
Monnig, E. C., 1984. Review of State Siting Criteria for Hazardous
Waste Treatment, Storage, and Disposal Facilities. Radian
Corporation Technical Report to the U.S. Environmental Protection
Agency, Office of Solid Waste. Research Triangle Park, NC.
Hoffman, J. S., D. Keyes, arid J. G. Titus, 1983. Projecting Future Sea
Level Rise: Mathodology, Estimates to the Year 2100, and Research
Needs. U.S. Environmental Protection Agency, Office of Policy and
Resource Management. EPA 230-09-007 Revised. Washington, D.C.
Rib, H. T. and Ta Liang, 1978. Recognition and Identification (of
Landslide Potential) in Landslides: Analysis and Control.
L. Schuster and R. J. Krizek, eds. National Research Council,
Transportation Research Board. Special Report 176.
Washington, O.C.
Mitnzer, 0. W. and R. A. Struole, 1965- Manual of Terrain Investigation
Techniques for Engineers. Engineering Experiment Station. Ohio
State University. Raport 196-2 and Appendix I. Columbus, OH.
Helm, [J. C., 1984. Field Based Computational Techniques for Predicting
Subsidence Due to Fluid Withdrawal in Reviews in Engineering
Geology, Volume VI: Man Induced Subsidence. T. L. Holzer, ed.
Geological Society of America, Boulder, CO.
4-42
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Holztr, T. L , 1984. Ground Failure Induced by Ground-Water Withdrawal
from Uncorwo 11 dated Sediment. In: Reviews in Engineering Geology,
Volume VI: Man Induced Subsidencs. T. L Holzer, ed. Geological
Society of America. Boulder, CO.
Dunrud, C. R., 1976. Some Engineering Geologic Factors Controlling Coal
Mine Subsidence in Utah and Colorado. U.S. Geological Survey
Professional Paper 969.
Heath, R. C., 1984. Ground-Water Regions of the United States.
U.S. Geological Survey Water Supply Paper 22-12. U.S. Government
Printing Office. Washington, D.C.
Hunt, C. B., 1974. Natural Regions of the United States and Canada.
W. H. Freeman and Company/San Francisco, CA.
4-43
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5.0 FUTURE AGENCY EFFORTS
The Location Guidance and Regulatory Program Under
40 CFR Part 264
The Agency recognizes the need for comprehensive
hydrogeologic standards to supplement existing land disposal
facility design, operation, and ground-water protection
standards. As a first step in developing a location program,
the Office of Solid Waste and Emergency Response will issue
a series of guidance manuals in phases for use by RCRA land
disposal facility permit writers as well as owner/operators.
These manuals will be designed to assist the reader in evalu-
ating hydrogeologic conditions that exist at a particular
facility location.
This manual (Phase I) identifies five criteria for
location acceptability that, if not met, may warrant permit
denial under the present Part 264 permitting standards and
other Federal statutes and regulations. A second RCRA guid-
ance (Phase II) will supplement the Agency's Ground-Water
Protection Strategy and will reference guidance pursuant to
the Strategy. An important factor in the implementation of
this Strategy will be the definition of ground-water
"vulnerability." The Agency's response to facility location
over several classes of ground water and usage classifica-
tions will depend upon whether or not the facility is in a
vulnerable hydrogeologic setting that can lead to contamina-
tion of the ground water. The guidance will present a defini-
tion of site acceptability based upon how vulnerable the usable
ground water is to contamination. In addition, the manual
5-1
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will provide permit writers with step-by-step means of
evaluating whether or not various criteria for an acceptable
site are met and technical methods for analyzing hydrologic
and geologic factors including subsurface flow conditions
and contaminant time of travel. Technical methods will be
calibrated and tested using actual RCRA facility location
data and other sources, and risk assessment techniques.
Locational issues discussed in the Phase I manual will be
highlighted in a series of Phase II appendices that will
illustrate the use of various graphic and simulation tech-
niques for evaluating location.
In addition to the guidance manuals described above,
the Agency has begun a longer-term program to revise current
RCRA standards to incorporate hydrogeologic concerns.
Hydrogeologic criteria are needed to help provide long-term
protection of public health and the environment. A 1983 EPA
study (Liner/Location Study by Ertec Atlantic, Inc.) conclud-
ed that proper site selection and appropriate hydrologic and
geologic conditions are important factors in maintaining
long-term protection of the environment. The pending RCRA
reauthorization is likely to contain specific amendments
that require the Agency to promulgate location regulations.
In addition, the Agency's Ground-Water Protection Strategy
directs the need for location regulations based on ground-
water classification and vulnerability.
The following table describes the major milestones of
the program:
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PROGRAM MILESTONE FOR RCRA LOCATION GUIDANCE
AND REGULATIONS
Table 5.0-1:
Program Milestone
1. Background Support Document - Review of State
Siting Criteria
2. Issue Technical Guidance
A. Permit Writers' Guidance Manual for the
Location of Land-Based Hazardous Waste
Storage and Disposal Facilities
Phase I: Criteria for Acceptable
Locations
- Explains use of existing applicable RCRA
regulations and other Federal statutes
Phase II: Technical Methods for Evaluating
Location
Incorporates the GWP Strategy and
references classification guidance
Defines vulnerable and nonvulnerable ground
water based on ground-water flow analyses
Provides detailed methods for site analysis
Location Case Studies
Phase II technical methods and definition
of vulnerability tested and calibrated using
actual RCRA facility location data and other
sources
B. Permit Writers' Guidance Manual for the
Location of Hazardous Waste Land
Treatment Units
3. Regional Training Programs for Permit Writers
- Phases I and II Guidance Manuals
4. Begin Development of Proposed Hydrogeologic-Based
Location Standards Under 40 CFR Part 264
5. Propose Hydrogeologic-Based Location Standards
Under 40 CFR Part 264
6. Promulgate Final Hydrogeologic-Based
Location Standards Under 40 CFR Part 264
7. Regional Training Programs for Permit Writers
- Location Standards Under 40 CFR Part 264
Completion
January 84
(Revised
September 84)
November 84
June 85
(in progress)
June 85
(in progress)
(in progress)
5-3
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6.0 REFERENCES
Algermissen, S.T., Seismic Risk Studies in the United
States. Proceedings of the Fourth World Conference
on Earthquake Engineering, Santiago, Chile, 1969.
Cowardin, L. M., P. C. Golet, and E. T. LaRoe, 1979.
Classification of Wetlands and Aquatic Habitats of
the United States. U.S. Fish and Wildlife Service
Publication No. FWS/OBS 79/31.
Dunrud, C. R., 1976. Some Engineering Geologic Factors
Controlling Coal Mine Subsidence in Utah and Colorado.
U.S. Geol. Survey Prof. Paper 969.
GAO, Alternatives to Protect Property Owners from Damages
Caused by Mine Subsidence. Bureau of Mines, CED-79-25,
February 14, 1979.
Hoffman, J.S., O.K. Keyes, and J.G. Titus, 1983. Projecting
Future Sea Level Rise. Office of Policy and Resource
Management, U.S. Environmental Protection Agency, EPA
230-09-007, Washington, D.C.
Holzer, T. L. , 1984. Ground Failure Induced by Ground-Water
Withdrawal from Unconsolidated Sediment. Published in
"Man-Induced Land Subsidence." Volume VI of Reviews in
Engineering Geology. Geo. Soc. Am. Boulder, CO.
Mullineaux, D. R., 1976. Preliminary Overview Map of
Volcanic Hazards in the 48 Conterminous United States.
U.S. Geological Survey. Miscellaneous Field Studies
Map MF-786, Scale 1: 7,500,000.
Thornbury, W. D., 1969. Principles of Geomorphology.
John Wiley and Sons, Inc. New York, NY.
Wiggins, J.H., Slosson, J. F., and J. P. Krohn, 1978.
National Hazards - Earthquake, Landslide, Expansive
Soil Loss Models. J. H. Wiggins Company Technical
Report. Redondo Beach, CA.
•U.S. aOVERWOMT PHIMTING OFFICE: 1985-46,-221/i4o42
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r•-viw. • .••.:-.! r,: r-vti'on Agency
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