&EPA
                              United States
                              Environmental Protection
                              Agency
                             Office of
                             Solid Waste and
                             Emergency  Response
9355.3-18FS
EPA/540/F-95/009
PB95-963412
August 1995
Presumptive   Remedies:
CERCLA  Landfill   Caps  RI/FS
Data  Collection  Guide
  Office of Emergency and Remedial Response
  Hazardous Site Control Division (5203G)
                                                    Quick Reference Fact Sheet
Municipal landfills constitute approximately 20 percent of all sites on the Superfund National Priorities List. Approximately 75 percent
of all CERCLA Municipal Solid Waste Landfill (MSWLF) Remedial Actions call for installation of a landfill cap.  The remedy
selection process for MSWLFs  is the basis of a U.S. Environmental Protection Agency (EPA) guidance, Conducting Remedial
Investigation/Feasibility Studies  for CERCLA Municipal Landfill Sites  (U.S. EPA, 1991), which establishes the framework for
containment (including landfill cap construction, leachate collection and treatment, ground water treatment, and landfill gas collection
and treatment) as the presumptive remedy for MSWLFs.

In 1992, EPA introduced the Superfund Accelerated Cleanup Model (SACM) to accelerate all phases of the remedial process. The
presumptive remedy initiative is one tool for speeding up cleanups within SACM. One way that presumptive remedies can streamline
the remedial process is through early identification of data collection needs for the remedial design.  By collecting design data prior
to issuance of the Record of Decision (ROD), the need for additional field investigations during the remedial design (RD) will be
reduced, thereby accelerating the overall remedial process for these sites. Data needed for design also can be useful in better defining
the scope of the remedy and in improving the accuracy of the cost estimate in the ROD. Since containment is the presumptive remedy
for MSWLFs, the Remedial Project Manager (RPM) can begin making arrangements to  collect landfill cap design data  as soon as a
basis for remedial action is established (e.g., ground water contaminant concentrations  exceeding maximum contaminant levels
[MCLs]).

This fact sheet identifies the data pertinent to landfill cap design that will be required for most sites. These data are organized within
six categories: (1) waste area delineation; (2) slope stability and settlement; (3) gas generation/migration; (4) existing cover assessment;
(5) surface water run-on/run-off management; and (6) clay sources. For reference, all data requirements and data collection methods
discussed in this document are summarized in a table at the end of this document (Table 2). In addition to  the following guidance
provided in this fact sheet, RPMs should enlist the aid of technical experts familiar with landfill  cap design in establishing data
collection needs for  specific sites.
TECHNICAL AREA 1: WASTE AREA DELINEATION

The area of a landfill cap is determined by the horizontal extent of previous waste disposal. One of the major causes of cost escalation
for MSWLF sites has been the failure to establish the actual boundaries of the waste.  Costly construction change orders have been
required to increase the area of the cap because wastes have been found to extend well beyond the edges of the intended cap. Waste
boundaries should be identified as accurately as practicable prior to initiation of the  design.
Aerial photographs, maps, and a local  newspaper  subject
search may provide a historical record of the extent and type
of disposal  activities conducted at the site. If  appropriate,
residents  could be  interviewed to confirm or  supplement
available information.

Field investigation should be used to confirm records and to
collect data  to delineate the outer boundaries of the waste.
Field investigations normally include surface, subsurface, and
                            noninvasive geophysical explorations.   Field  investigation
                            methods that provide information on the surface and shallow
                            subsurface extent of waste include excavating shallow test pits,
                            using direct-push exploration techniques, and drilling bore-
                            holes. Additional subsurface investigation methods are used to
                            provide information on the vertical extent of waste.

                            Borings can be used to  estimate waste thickness and condition
                            of existing cover soils adjacent to or underlying the waste.

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However, drilling into or through  the  waste and into  the
underlying soils and/or bedrock should be performed only if
necessary, and only if the driller is experienced in the methods
used to  prevent cross-contamination.  Additional  health  and
safety concerns (especially exposure to methane gas) must be
addressed in the health and  safety plan when borings  are
located in the waste.

Visual evidence of the waste boundary  or subsurface contami-
nation from these field  investigation activities  should be
recorded and, if necessary, verification samples  should be
collected and shipped for laboratory  analyses.

Surface geophysical methods also may be useful in  delineating
the waste boundary.  Each method has limitations, and  the
selection of an appropriate method should be based on landfill
characteristics and data needs.  The most commonly employed
geophysical methods include:

•   Magnetometry  (measures minor  changes  in earth's  mag-
    netic field)—location of waste boundary and distribution of
    metallic  waste
                                                                  •  Electromagnetic Conductivity (response to  artificially
                                                                     induced magnetic field)—location of areas of contrasting
                                                                     conductivity, such as a landfill or natural deposits

                                                                  •  Ground-Penetrating  Radar (reflection of electromagnetic
                                                                     waves)—determination of horizontal  extent and depth of
                                                                     disturbed soils and buried objects (often used to confirm
                                                                     magnetometry)

                                                                  •  Electrical  Resistivity  (measures  earth's   response  to
                                                                     electrical  current)—determination  of  edge of  landfill by
                                                                     subsurface resistivity difference

                                                                  •  Seismic Refraction (natural  or induced compression
                                                                     waves)—estimation of depth to  geologic strata and bedrock
                                                                     adjacent to the landfill.

                                                                  These  noninvasive surface geophysical  methods should be
                                                                  performed prior to invasive explorations  (e.g., borings or test
                                                                  pits). This will allow for the more limited intrusion  activities
                                                                  to verify the findings of the noninvasive exploration methods.
TECHNICAL  AREA  2:  SLOPE  STABILITY AND SETTLEMENT
Waste settlement and/or slope failure of the waste and existing cover soils can occur during construction of, or after completion of,
the cap.  Waste settlement or slope failure (see Figure  1) may expose waste and require  costly repairs. Data are needed on degree
of slope, existing cover materials, and existing  cover  soils  to  create cross-sectional  diagrams for use in evaluating landfill slope
stability and the potential for settlement damage.

                                                                  stability problems such as slippage failures in the waste and/or
                                                                  existing cover soil. Differential settlement occurs when one
                                                                  area  of waste settles more  readily than another because of
                                                                  differences in moisture content, waste compaction, or waste
                                                                  composition.  Settlement  (magnitudes typically range from 5
                                                                  to  25 percent of the initial  waste thickness),  and especially
                                                                  differential settlement, may create cracks in the cap and allow
                                                                  rainwater to reach the waste.  Changes in the topography of the
                                                                  landfill because of settlement may also create areas on the cap
                                                                  surface where rainwater can  pond.

                                                                  In  creating the  conceptual landfill  cap design, three separate
                                                                  calculations are  conducted

                                                                  •   Stability of waste—largely depends on how well the waste
                                                                     was compacted when placed, waste layer thicknesses, and
                                                                     waste composition

                                                                  •   Stability of the cap (existing and proposed)

                                                                  •   Settlement of waste—largely  depends  on how well the
                                                                     waste was compacted when placed, waste layer thicknesses,
                                                                     age, rate of  waste degradation, and waste composition.

                                                                  Because  of their heterogeneous nature,  the settlement  and
                                                                  stability of municipal wastes  are difficult  to predict. Settle-
                                                                  ment rates of selected areas  of the waste can be  measured by
                                                                  placing survey  monuments  on top of the  waste and taking
                                                                  periodic measurements to determine the change in elevation of
    Figure  1. Typical slope failure  at  MSWLF site.
Settlement in a landfill can be  caused by factors  such as:
biodegradation of wastes,  consolidation of waste under the
weight of waste  material and  cap, deterioration of partially
filled containers  (e.g.,  drums),  or  compaction  of material
during landfill  operation or  cap installations.    Possible
consequences of settlement include instability  in the waste or
cover soil, which can damage the cap.  In fact, a recent article
on cap design reports that  "The center of a 20-foot diameter
section of a landfill cover, for instance, could settle only 0.5 to
1.5 feet  before  significant cracking  [of the composite  clay
liner] could  be  expected." (Koerner and Daniel, 1992)  For
this reason,  settlement  potential  and  stability of the landfill
system should be evaluated concurrently.

The weight of the new cap can  be significant enough to cause
additional waste settlement and compaction.  The effect of this
additional weight may initiate differential settlement across the
cap,  thus compromising the integrity of the cap, or create

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 the monuments. Because settlement generally occurs slowly,
 it is important to begin measurement early, preferably during
 the remedial investigation.

 The settlement of the waste depends on thickness and general
 composition of the waste and existing topography. Compress-
 ibility  characteristics are  derived  from  preload  tests and
 empirical correlations to data in the  published literature. Data
 from surveying monuments, settlement plates, and topographic
 surveys can be  used  to determine surface settlement rates
 across the landfill.

 The stability  of waste can be determined by evaluating  the
 following:

 •   Potentiometric surface and perched water table informa-
    tion—can be determined  using water level measurements
    from piezometers and monitoring wells

 •   Thickness of waste

 •   Existing  topography-can  be  determined from  site
    reconnaissance  and topographic surveys.

 Ground motions induced by  earthquakes (seismic events) can
 also affect cap performance through a decrease in  slope sta-
 bility.  This fact  sheet  does not address the additional data
 required for cap designs  for landfills located in seismic impact
 zones.

 The waste thickness and composition can be determined by
 observing and sampling (during  completion  of test pits,
 borings, and hand-augered holes with an experienced driller)
 and by searching through historical records.

 The existing cover soil should also be evaluated to determine
 its stability  and potential  for  settlement.   Studies for  the
 stability of the existing cover soil could include:
                       • Maximum  Slope
                       • Soil  classification
                       • Potentiometric  surface
                       • Shear strength
                       • Thickness
                       • Density

                       Slope measurements and potentiometric surface derivations can
                       be obtained using the same procedures used to determine waste
                       characteristics. The remaining data can be obtained by boring,
                       piezocone penetrometer (PCPT), geophysical techniques,  and
                       test pits. Existing cover soils should be classified by grain size
                       and  hydrometer analysis,  as  well as  by Atterberg limits
                       performed on borings and test pit samples. See the summary
                       table at the end of this fact sheet (Table 2) for recommended
                       tests to determine the shear strength for fine-  and coarse-
                       grained soils.

                       The  stability and settlement estimates for existing cover  soil
                       depend largely  on the  complexity  of the  landfill  site.
                       Investigations necessary to evaluate physical properties of the
                       existing cover soils  will depend on the type(s)  of soils
                       encountered. If the existing cover soils are soft silts and clays,
                       the  settlement  and stability evaluations will be more complex
                       than for sands and  gravels.  These soil samples should be
                       collected during drilling of monitoring wells to save time and
                       money, usually during the remedial investigation (RI).

                       Additional slope stability evaluations will be performed during
                       landfill cap design.  Slopes greater than 3:1  (3 horizontal/
                        1 vertical) and landfills that have been constructed within or
                       adjacent to  wetlands  or low-strength soils are of particular
                       concern. These areas  of concern should be identified during
                       RI/FS data collection to the extent possible.
 TECHNICAL AREA 3: GAS GENERATION/MIGRATION
Assessment of the rate and composition of gas generated in the landfill will determine whether or not a gas collection layer should
 be included as a component of the cap. Dangers of gas generation and uncontrolled migration include vegetative kill,  health risks
from exposure, and explosive or lethal gas buildup within and outside of the landfill (see Figure 2). Field monitoring for the presence
 of landfill gases is also important in developing safety parameters and reducing health risks to personnel working on site.
                       Volatile
          Damage to  Emissions
          Vegetation
                                Lateral
                               Migration
Explosive
  Risk
       Figure  2. Vertical and lateral migration of
            generated gas from MSWLF site.
Generation  of gas  typically results from  the biological
decomposition of organic material in the wastes. The rate and
process of gas generation are dependent on the availability of
moisture, temperature, organic content of the  waste,  waste
particle size, and waste compaction.

Data  immediately available  in  the field for assessing gas
generation are landfill gas composition and gas pressure. Gas
composition in  soils usually is evaluated  in  the  field by
monitoring or sampling through gas probes using a methane
meter, explosimeter, or organic  vapor analyzer.  Air samples
should  be  analyzed  for  the presence  of  volatile organic
compounds  (VOCs)  or  semivolatile  organic  compounds

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(SVOCs). Moisture and heat content also can be determined
by the laboratory or in the field with hand-held instruments.
This information may be necessary to assess possible treatment
alternatives for collected  gas.

Gas migration  is  a  function  of site  geology,  chemical
concentration, and  pressure  and density gradients.   Gases
migrate through the  path of least resistance (e.g., coarse and
porous  soils, bedding  stone  along nearby water and sewer
lines). Data for evaluating gas migration control and treatment
methods include the composition of any existing landfill liners,
soil  stratigraphy,  depth to  water table, proximity of human/
ecological receptors, and the locations of buried utilities and
other backfilled excavations and structures.

Gas migration pathways may be identified based on knowledge
of the site geology, hydrogeology, and surrounding soil  charac-
teristics and  by review of water and  sewer maps.  Some of
these data may  be  obtained by  collecting and evaluating
samples from  test  pits, borings,  or  hand-augered   holes.
Piezocone data also  may be  cost-effective for characterizing
the surrounding subsurface soils at larger MSWLF sites.

Potential receptors of landfill gas emissions may be  identified
through site reconnaissance, and receptor locations should be
monitored to assess possible accumulation of migrant landfill
gases.  Atmospheric  monitoring at receptor locations may be
done using a flame ionization detector (FID), a photoionization
detector (PID), or a  gas  monitoring station; however,  a PID
will  not detect methane  and thus cannot be used  to  assess
explosion risk.  An oxygen meter using the Lower Explosive
Limit (LEL) indicator may be used to detect explosive levels
of gas.

Gas  control is accomplished through either passive or active
gas collection.  Treatment of collected gas  may be  required
depending on the concentration of hazardous constituents. The
gas control system required will depend on the proximity of
receptors, permeability  of  migration  pathways,  State  and
Federal regulations and guidelines,  and  level and rate of gas
generation. Effective gas disposal  methods include flaring,
processing and sale,  and/or sorption.

Active  gas collection may  be  necessary  to  control  gas
migration when receptors are, or  are expected to be, at risk.
Active gas collection generally is required when measurements
exceed either

•  5% methane at the  properly line or cap edge, or

•  25% methane LEL  in/at on-site structures. (This subject is
   further addressed in the U.S. EPA Technology Brief Data
   Requirements for Selecting Remedial Action  Technology
   [U.S. EPA, 1987].)

A gas pumping test can be used to improve the estimate of the
gas permeability of the waste materials and  unsaturated soils,
number of collection  wells required, piping size and configura-
tion, and blower requirements. However, gas pumping tests
should not be relied  on without further  measurement  and
adjustment during construction.
TECHNICAL  AREA  4:  EXISTING COVER ASSESSMENT
Existing landfill caps should be evaluated to determine whether or not any components can be reused in the construction of a new
cap. Use of existing components could save both time and money.
Data on existing components can be readily collected because
only materials  above the  waste need be sampled. Sampling
locations and  procedures  that will minimize damage to
geosynthetic materials should be used. Sampling holes should,
at a minimum, be refilled with bentonite if the existing  cap is
composed of clay. Geosynthetics should be patched with mate-
rials of equal properties following manufacturer's guidelines.

Additionally,  the site  reconnaissance should  be  used to
evaluate, in general, the need for regrading the landfill surface
to achieve proper side slopes.  Appropriate limits to the
steepness of slopes can be determined from preliminary slope
stability calculations. Excavation into landfill waste materials
may be required to reduce slope steepness to acceptable limits.

Table  1  provides recommended guidelines  for final  cover
designs. The assessment of the existing cover should include
an evaluation of the potential for any components to meet  final
cover guidelines.
      Table  1.  Existing Cover Assessment Data
    Requirements and Recommended Guidelines
       Data
   Requirements
Recommended  Guidelines"
     (for Final Cover)
  Slope (top)        3% to 5% minimum for drainage
  Cap Area          Covers horizontal waste limits
  Vegetative/Soil      Vegetative soil supporting healthy low
  Layer             shrubs or grass, no erosion, gullies or
                   deep-rooted plants, no unacceptable frost
                   heaves or settlement
  Drainage Layer    Permeability >1x102cm/s (sand, gravel,
                   or geosynthetic)
  Barrier Layer      Two-component (geomembrane atop
                   compacted  clay") composite liner below
                   the frost zone
  Gas Venting       Either passive vents located at high points
  System            (not clogged,  no settlement) or extraction
                   and treatment system working properly
a Refer to EPA's Technical Guidance  Document: Final Covers on
  Hazardous Waste Landfills and Surface Impoundments (U.S. EPA,
  1989).
b Clay compacted to a permeability  < 1 x1 0 7cm/s, geomembrane
  thickness > 20 mil.

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 TECHNICAL AREA 5:  SURFACE  WATER  RUN-ON/RUN-OFF  MANAGEMENT

 The surface area and gradient of landfill slopes will affect surface water control measures. For the protection of both the landfill cap
 and adjacent areas (see Figure 3), the design of the final remedy should ensure that the site layout will provide adequate space for
 surface water diversion and containment/retention impoundments.
             Storm Run-off
               Overflows
             Containment
             Impoundment
                                         Silt-laden Water
                                         Impacts Stream
          Figure 3. Storm run-off impact from
                     an MSWLF site.

 RCRA Subtitle D minimum requirements for MSWLFs (40
 CFR Section 258.26) include providing a run-on control system
 capable of preventing flow onto the active portion of a landfill
 during the  peak discharge from a 25-year rain storm. The
 regulation also requires providing run-off control systems to
 collect, at a minimum,  the water volume resulting from a
 24-hour,  25-year  rainstorm.  RCRA  Subtitle  D regulations
 apply to the closure of active MSWLFs and may be Applicable
 or Relevant and Appropriate Requirements (ARARs) for cer-
 tain landfills at CERCLA sites as well.

 The  method for  estimating  run-on  and run-off design
 discharges  should  be based on engineering  judgment and
 on-site conditions (e.g.,  the Rational  Method  used  by
 hydrologists to determine overland flow). Detailed storm flow
 calculations usually are done during the design phase.  How-
 ever, data for preliminary calculations should be collected early
 enough to prepare  an estimate of the cost of run-on/run-off
 control measures as part  of the remedy estimate for the  ROD.

 Because run-on and run-off control is required for operating
 landfills,  some landfills may  already have  surface  water
 diversion or containment impoundments that allow sediment

 TECHNICAL AREA 6:  CLAY SOURCES
to settle out of the run-off and that control discharge  for a
25-year storm. Depending on when  the landfill was designed
(with respect  to  applicable  Federal and State regulations),
existing control structures may not have adequate capacity. In
addition, the RI/FS should identify areas for temporary surface
water controls for use during cap construction activities.

A review of the original design or site records available for a
landfill  may provide  information on design criteria  for the
surface water control structures. Site  reconnaissance should be
conducted to evaluate the physical condition of the system. If
there are no existing diversion or containment impoundments,
adequate space should be located on or off site to accommo-
date them.  Property  acquisition may be necessary if on-site
space is not available.

Prior to cap installation, collected or diverted run-on  surface
waters often can be discharged to a nearby surface waterbody
or to a recharge  basin.   Discharge to surface water is
considered  a point source discharge and must comply with the
National Pollution Discharge Elimination System (NPDES)
requirements of the Clean Water Act. Because many States
have jurisdiction for  the discharge  of pollutants to  surface
waters, permit requirements may  vary depending  on location,
although an NPDES permit is always needed. Other factors to
consider are the water quality and  soil type, which  can be
determined by analysis of surface water samples, visual and
sieve analyses of the soil,  and review of NPDES compliance
data (if applicable).

After the cover is  installed, the collected or diverted  surface
water is not contaminated;  therefore,  diversion or  containment
impoundment  maintenance usually  is limited to control of
vegetation  and debris and sediment  removal.  Discharge to a
recharge basin is not considered a point source discharge and,
generally, regulators evaluate these basins for  permit compli-
ance on a case-by-case basis.
 A compacted clay layer is normally one of the primary components of an effective cap, provided that sources of clay (low-permeability
 soil)  are available  at or near the landfill. Data-gathering activities should include looking for potential on-site/local clay deposits
for the cap construction.  Manufactured geosynthetic clay liners should be considered if the required volume or physical properties
 are not available in nearby soils. A comparison of geosynthetic clay liner material cost versus clay excavation and transport cost
 should be completed before design commences.
 Investigation of potential  sources for clay should be initiated
 prior to the preliminary conceptual cap design (which defines
 the  components  of the cover).   For  information  on clay
 deposits,  the  Soil  Conservation  Service (SCS)  of the U.S.
 Department of Agriculture (USDA)  publishes soil maps and
classifications  by county.   Additional  information  on the
availability of clay soils may be obtained from State natural
resource inventory programs; local contractors or engineering
firms practicing in the area; State and local highway officials,

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shallow  borings,  test  pits,  and  hand-augered  holes;  and
geotechnical laboratory  testing.

After potential sources of clay are identified, a site  recon-
naissance may be  conducted. The site reconnaissance  should
include sample collection via hand-augered holes or shovels to
verify the availability of clay over the site.

Subsurface soil samples of the source area should be collected
later to  determine resource  quality  (shear testing  of layer
interfaces) and quantity. Procedures used to characterize clay
sources generally include:

•  Excavation of at least one test  pit for every 25,000  to
   50,000 cubic yards

•  Collection of soil  samples from  test  pits for laboratory
   characterization

•  Shallow borings to confirm  soil type,  volume, and,  in
   certain instances, depth to ground water

•  Laboratory testing of samples collected including: grain
   size  analysis,   Atterberg   limits,  permeability   testing,
   moisture  content,  and  compaction  testing.    Detailed
   compaction  requirements  to  meet construction  quality
   assurance objectives are provided in Quality Assurance and
   Quality Control for Waste  Containment Facilities (U.S.
   EPA,  1993 b).

If sufficient quantities of soil cover materials with appropriate
engineering properties are not available within an economically
                    practicable distance  from the project site, geosynthetics  or
                    processed natural materials should be considered. Geosynthetic
                    clay  liners are generally manufactured by either sandwiching
                    bentonitic clays between geotextiles or affixing the bentonitic
                    clay to the bottom surface of a membrane. Thus, if clay is not
                    readily available, low-permeability layers of the cap may be
                    comprised of either available soil that is  processed by adding
                    bentonite to reduce the permeability or geosynthetic clay liners.
                    For cap drainage layers, geosynthetic drainage  nets may also
                    be used, in lieu of coarse sand and gravel, to meet performance
                    requirements. Information  on geosynthetic clay  liners and
                    drainage nets can be obtained from manufacturer catalogues.

                    CONCLUSION

                    For each MSWLF site where capping is clearly  a preferred
                    remedy, the RPM should assemble a technical review team to
                    determine the design data to be collected. This team should
                    include experienced RPMs and technical experts familiar with
                    data  collection needs for cap design.  The team can help the
                    RPM in defining the field work required and its timing and in
                    reviewing the design data submitted by the contractor. In the
                    event that the contractor is changed (i.e., the RI/FS is Fund-led
                    and the design  is switched  to Potentially Responsible Party
                    [PRP]-led), the  technical review team  can assist the RPM in
                    transferring the  pertinent  collected design data to the new
                    contractor.

                    Table 2 summarizes the data needs and collection methods
                    presented in this fact sheet.   This table  should be used  as a
                    reference when determining necessary design  data collection
                    activities.
                              Table  2.  Data Requirements  and Collection Methods
             Data  Requirements
                                                                        Data Collection Methods
 Waste Area Delineation
     Design/historical information
     Horizontal extent of waste

     Depth and thickness of waste
Historical records, personal interviews
Test pits, probes, hand-augered holes, magnetometry, electromagnetic
conductivity, ground-penetrating radar, electrical resistivity, seismic refraction
Borings, geophysical surveys	
 Slope Stability and Settlement'
     Waste Evaluation
       Slope measurement (A)
       Potentiometric surface (A)
       Compressibility characteristics (C)
       Settlement rate (C)
       Thickness of waste (A,C)

       General waste composition (A,C)

 	Existing topography (A,C)	
Slope inclinometers, topographic survey
Piezometers/monitoring wells
Preload testing, empirical correlations to published literature
Survey monuments, settlement plates, topographic survey
Observation and sampling during test pits, borings, hand-augered holes, historical
records, geophysical  surveys
Observation and sampling during test pits, borings, hand-augered holes, historical
records, geophysical  surveys
Site reconnaissance, topographic survey, historical photographs	
                                                                                                               (continued)

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                                                  Table 2  (continued)
             Data Requirements
                                                                        Data  Collation  Methods
 Existing Cover Soil Evaluation'
    Slope measurement (A,B)
    Soil classification (B)

    Potentiometric surface (A,C)
    Shear strength  (B)
    Compressibility characteristics (C)

    Density (B)
                   Topographic survey, slope inclinometers
                   Grain size analysis, hydrometer analysis, Atterberg limits performed on
                   borings/test pit samples
                   Piezometers/monitoring  wells
                   Fine-grained soil (cohesion): Field and/or lab vane shear test, torvane, pocket
                   penetrometer, piezocone penetrometer, unconfined compressive strength,
                   empirical correlations to Standard Penetration Test (S-P-T)
                   Coarse grained soil (friction angle): Empirical correlations to S-P-T, direct shear
                   test, triaxial shear test, piezocone penetrometer
                   Consolidation tests performed on undisturbed tube samples collected from
                   borings. Empirical correlations to index properties (water content, plasticity).
                   Empirical correlations to S-P-T data, bulk density determination from undisturbed
                   tube samples  (fine-grained soils only)
 Gas Generation/Migration
    Gas composition and gas pressure
    Moisture and heat content
    Migration pathways
    Receptors
                    Gas probes,  monitoring wells, laboratory samples
                    Laboratory samples or handheld instruments in the field
                    Water and sewer maps, piezocone, test pits, borings, hand-augered holes
                    Site reconnaissance,  photoionization detector, flame ionization detector, air
                    monitoring station, oxygen meter
 Existing Cover Assessment
    Slope-top
    Cap area
    Vegetative/soil layer
    Drainage layer

    Barrier layer


    Gas venting system
                    Site reconnaissance, topographic survey
                    Site reconnaissance, borings, test pits, geophysical survey
                    Site reconnaissance, topographic survey, test pits
                    Site reconnaissance, borings, test pits, hand-augered holes, field infiltrometer or
                    laboratory samples for hydraulic conductivity
                    Test pits, borings, hand-augered holes, Shelby tubes for permeability, laboratory
                    samples/analysis for shear strength, compaction curve, atterberg limits,
                    freeze/thaw cycling, water content
                    Site reconnaissance, gas character sampling, gas  pumping tests
 Run-on/Run-off Management
     Estimated discharge, size of control
     structures, treatment requirements
     Climatic data
     Run-on/run-off areas
     (% vegetated, % paved)
     Water quality
     Soil types
                    Review of design records, National Pollutant Discharge Elimination System
                    (NPDES) permit, detailed storm flow calculations
                    National Oceanographic and Atmospheric Administration (NOAA)
                    Site reconnaissance, topographic surveys, aerial photographs

                    Surface water sampling and analysis
                    Visual, aerial photographs, and soil maps from the Soil Conservation Service
                    (SCS)
 Clay Sources
     Soil properties
     Subsurface  resource adequacy and
     quantity (shear testing)
     Geosynthetic clay liner properties
                    Soil maps from the SCS, local contractors or engineering firms, state/local
                    transportation officials, natural resource inventory programs, shallow borings,
                    hand-augered holes, test pits, and geotechnical laboratory testing
                    Grain size analysis, Atterberg limits,  permeability test, moisture content,
                    compaction test, shallow borings, test pits, laboratory testing
                    Manufacturer catalogs, literature, EPA studies/guidance
"The letters following the slope stability and settlement and existing cover soil evaluation data requirements are referenced to the data needed to
  perform the three separate calculations used to evaluate slope stability and settlement of the landfill cover (see Technical Area 2):
  A = Stability of waste.
B = Stability of cap components.
                                                           C = Settlement of waste.

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BIBLIOGRAPHY

Koemer,  R., and Daniel,  D.  1992.  Better cover-ups.  Civil
   Engineering, May:55-57

U.S. Army Corps of Engineers (Moses, D.).  1993. Checklist
  for Landfill Cover Design. Draft.  May.

U.S. EPA (Environmental  Protection Agency).  1985. Covers
  for  Uncontrolled Hazardous  Waste  Sites.  EPA/540/2-
   85/002.

U.S. EPA (Environmental Protection Agency).  1987. Data
   Requirements for Selecting Remedial Action Technology.
   EPA/600/2-87/001.
U.S. EPA  (Environmental Protection Agency).     1989.
   Technical Guidance  Document:    Final Covers  on
   Hazardous  Waste  Landfills and Surface Impoundments.
   EPA/530/SW-89/047.  July.

U.S. EPA  (Environmental Protection Agency).     1991.
   Conducting Remedial Investigations/Feasibility Studies for
   CERCLA Municipal Landfill Sites.    EPA/540/P-1/001.
   Office of Emergency and Remedial Response. February.

U.S. EPA  (Environmental Protection  Agency).     1993a.
   Engineering Bulletin: Landfill Covers. EPA/540/S-93/500.

U.S. EPA  (Environmental Protection  Agency).     1993b.
   Technical  Guidance Document: Quality Assurance and
   Quality Control for  Waste Containment Facilities.
   EPA/600/R-93/182
For more information contact:
   Kenneth Skahn
   Office of Emergency and Remedial Response
   (703) 603-8801
   or
   Superfund Hotline
   (800)  424-9346
 NOTICE: This fact sheet is intended solely for informational purposes and cannot be relied upon to create any rights enforceable
 by any party in litigation with the United States.
 oEPA
United States
Environmental Protection
Agency (5203G)
Washington, DC 20460

Official Business
Penalty for Private Use
$300

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