TD367
.R37
1982y
                                             OOOD82002
                             DRAFT


                      RCRA GUIDANCE DOCUMENT


                        WASTE PILE DESIGN


                          LINER SYSTEMS





                [To be used with RCRA Regulations


             Sections 264.251U), 264.252  and  264.2533
                                    ISSUED:  ?/  /82

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U,S.
                              ••••••->•-,

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                      TABLE OF CONTENTS
A.  Purpose and Use
B.  Liner System Function, Components, and Life
    1.  The Regulations
    2.  Guidance
    3.  Discussion
C.  Leachate Detection, Collection, and Removal Systems
    1.  The Regulations
    2.  Guidance
    3*  Discussion
D.  Liner Specifications
    1.  The Regulations
    2.  Guidance
    3.  Discussion
E.  Waste Piles Eligible for Exemption from Subpart F
    1.  The Regulation
    2.  Guidance
    3*  Discussion
Appendices
    A.  Hydraulic Conductivity Test Method
    B.  Compatibility Test Method

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A.   Purpose and Use
     This guidance document is intended to supplement the
regulations in Part 264, Subpart L, applicable to owners and
operators of facilities that use waste piles to store or treat
hazardous wastes.1/  The design requirements in Subpart L
are expressed in terms of the performance to-be achieved by
a pile's design rather than specific design  standards
such as type and thickness of liner material.  Because of the
non-specific nature of the regulations, the  Agency is using
this guidance to assist both permit applicants and permit
writers in determining what constitutes an acceptable lineyr
system design.  It contains liner design specifications- which
the Agency considers as. meeting the design requirements of
§264.25Ka).
     The designs included in guidance at this time are by no
means intended to cover the entire spectrum  of acceptable  •
liner systems.  Indeed, all of the designs included are
intended only for use in the unsaturated zone (i.e., above '
the high water table).  This does not mean that the Agency
has ruled out the location of facilities in  the saturated
zone.  However, permit applicants seeking to locate in the
I/  Prior to reading this guidance document, the reader should
familiarize himself with the regulations in Subpart L -
of Part 264 and the associated preamble discussions.

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saturated zone cannot necessarily rely on the designs
specified irf this guidance but rather must demonstrate that
their intended design meets the standards of §264.251(a),
in their specific location.
     The Agency Intends to supplement this guidance with
additional designs in the future.  It is expected that
these additional designs will address location in the saturated
zone.  However, the Agency anticipates that most waste piles
will be located on and above the land surface and hence the
need for specifying designs suitable for placement in the
saturated zone is less compelling for waste piles than for
other types of disposal units.
     The basic performance goal for waste pile liner designs
is that they prevent the release of hazardous constituents
to ground and surface waters through closure.  Subpart L
covers only waste piles from which all wastes, waste residues,
containment system components (e.g., liners), and contaminated
subsoils will be removed at closure.  Waste piles from which
wastes, waste residues, contaminated containment system
components, and contaminated subsoils will not be removed at
closure are regulated as landfills under Subpart N.
     As promulgated on January 12, 1981, Subpart L included
two acceptable waste pile designs, both of which were Intended
to provide complete containment.  In essence, these designs
were either an essentially impermeable base of sufficient
strength to allow for the periodic removal of all wastes from

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the pile in order to physically inspect the base or a double
liner with a leachate detection, collection, and removal
system.  Both of these designs are included in this guidance
with further elaboration on specifics such as liner material
and liner thickness.
     In accordance with the revised Subpart L, however,
waste piles are not limited to employing one of these two
designs.  Therefore, this guidance also prescribes designs-
which include either a single soil liner or a single synthetic
liner.
     This document is arranged according to the section of
the regulation to which it corresponds.  Those wishing to
send technical information or suggestions concerning this
document should address them to:  Rod Jenkins, Chief, Land
Disposal Branch, Office of Solid Waste, WH-565E, U.S.
Environmental Protection Agency, 401 M Street, S.W., Washington,
B.C., 20460.  EPA is particularly interested in information
and suggestions concerning the usefulness of the document,
expansion of it, and the effectiveness of the guidance
contained in ensuring compliance with the performance
requirements in the regulations.
     EPA is also producing a series of Technical Resource
Documents (TRDs), two of which cover caps and liners.  The
TRDs are designed to comprehensively but concisely present the
sum total of the body of information and experience gained by
the Agency over the years on a given topic.  As such, they

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contain factual summaries concerning the experiences and
effectiveness of design alternatives, covering what has been
found not to work, as well as what has been found to be
effective.  They contain no policy-related direction.  The
TRDs can be considered as technical background or development
documents supporting these guidance documents and the
regulations.  Based on the information contained in the TRDs,
the Agency made the policy decisions which resulted in the
regulations and these guidance documents.  One TRD that
corresponds to guidance in this document is Lining of Waste
Impoundment and Disposal Facilities (SW-870) NTIS Publication
No. PB-81-166-365.  It can be obtained from the National
Technical Information Service, U.S. Department of Commerce,
Springfield, VA  22161.  The Agency plans to publish an amended
version of this document in the Pall of 1982.
B.   Liner System Function, Components, and Life
     1.  The Regulations
     In accordance with §264.251(a), a waste pile liner system
must be designed, constructed, and maintained to prevent, through
scheduled closure, the migration of hazardous constituents
from the pile to the surrounding environment.  The liner may be
constructed of materials that may allow waste or hazardous
constituents to migrate into the liner, but must not allow
migration through the liner into the adjacent subsurface soil
or ground or surface water during the active life of the pile.

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All waste piles must be designed, constructed, and operated
with a leachate detection, collection, and removal system
above the primary liner.  Waste piles must be designed and
operated to maintain less than a 30 centimeter (1 foot)
                                                                >
leachate depth over the bottom of the pile.
     2.  Guidance
     (a)  Liner systems should be constructed wholly above
the seasonal high water table, i.e., in the unsaturated soil
or above grade (i.e., on the surface);
     (b)  As a minimum, the liner system should consist of a
single liner of soil (clay), synthetic material, or admixed
material;
     (c)  Where a synthetic liner is used under any pile
which will not complete closure for 30 or more years after
first placement of wastes, the underliner system should
consist of the following as a minimum:
     (i)  a primary synthetic liner; and
    (ii)  a secondary soil (clay) liner.
     (d)  All waste piles must have a leachate detection,
collection, and removal system installed above the primary liner.
     3.  Discussion
     In developing the designs contained in this guidance,
the Agency has attempted to come as close as possible to
complete containment for the life of the waste piles.  However,
the Agency also considered, as an overriding criterion, that
the designs included in this guidance be based on conventional

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technology, utilizing readily available equipment and materials,
at practical costs.
     Essentially complete but temporal containment is
practical using newly developed synthetic liners now on the
market.  However, experience with synthetic liners in contact
with chemicals is relatively recent, hence EPA has no experience
base from which to predict the life of these materials.
However, predictions based on chemistry and limited recent
real world experience are sufficient to convince the Agency
that with proper selection for resistance to wastes and
leachate at the site and proper installation (tight seams and
no tears), containment for at least 30 years is practical
using a single synthetic liner.  Therefore, a single synthetic
liner is described for waste piles which will complete closure
in less than 30 years.
     Soil liners, in contrast to synthetic liners, will
become saturated with leachate and will eventually release
hazardous constituents.  However, predictions can be made on
the flow time of leachate through soil liners.  Therefore,
if the soil used possesses appropriate properties, is properly
placed, and is of sufficient thickness, soil liners can be
expected to provide containment for the life of the waste
pile.  Thus, because Subpart L requires the removal of all
wastes and liners (including saturated clays), and any con-
taminated subsoils at closure, no hazardous constituents
should be released to ground-water, even if through damage,

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a small breach occurs in the liner system.
     A third option for waste piles is a single base of
admixed materials such as concrete or asphalt.  Such bases
must be thick enough to be structurally stable in the specific
location.  A structurally stable base is one which is not
prone to cracking or crumbling under the conditions to which
it will be exposed.  Appropriate base materials should be
chosen in consideration of the specific waste anticipated
to be stored or treated in the pile.
     For waste piles which will not close within 30 years and
which incorporate a synthetic membrane, the Agency suggests a
double liner system Incorporating a top synthetic liner and
a secondary soil (clay) liner.  With the double liner system,
if the primary synthetic liner deteriorates in the future,
the secondary soil (clay) liner will minimize transmission of
leachate henceforward.  Natural materials such as clay are
not prone to deterioration overtime and should function
essentially forever unless physically damaged or affected by
chemical constituents.  Liners of admixed materials such
as concrete or asphalt may also be used for long lived waste
piles when an analysis of the chemistry and physics of the
application indicates that the liner will not deteriorate
and lose function during the pile life.
     C.  Leachate Detection, Collection, and Removal Systems
     1.  The Regulation
     The regulations require waste piles to be designed and

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constructed with a leachate detection, collection, and removal
system.  In addition, waste piles must be designed and operated
to maintain less than a 30 centimeter (1 foot) leachate
depth over the bottom of the pile.
     Leachate detection, collection, and removal systems must
be constructed of materials that are chemically resistant to
the waste managed and leachate generated in the pile and of
sufficient strength and thickness to resist collapse and clogging
under the pressures exerted by overlying waste, cover material,
and equipment used at the pile.
     2.  Guidance
     Leachate detection, collection, and removal systems
should have:
     (a)  At least a 30 centimeter (12 inch) drainage layer
with a-hydraulic conductivity not less than 1 x 10~3 cm/sec
and a minimum slope of 2 percent; and
     (b)  A graded granular or synthetic fabric filter above
the drainage layer to prevent clogging,  except in the case of
leachate detection, collection, and removal systems in direct
contact with the primary synthetic liner.  If a granular
filter is used, the grain size should meet the following
criteria:
         D15 (filter soil)       < 5
         D85 (drainage layer)    ~
and
         D15 (filter soil)      =  5-20
         D15 (drainage layer)

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and
         D50 (filter soil)       < 25
         D50 (drainage layer)    ~"
where:
     D15  * grain size, in millimeters, at which 15/5 of the
            filter soil used, by weight, is finer:
     D85  * grain size, in millimeters, at which 8555 of the
            drainage layer media, by weight, is finer;
     D50  = grain size, in millimeters, at which 50/5 of the
            filter soil or drainage media, by weight, is
            finer; and
     (c)  A drainage tile system of appropriate size and
spacing and a sump pump or other means to efficiently remove
leachate.
     (d)  Where the waste is sufficiently porous that a one
or more foot head will not develop within the pile, the
owner or operator need only collect and manage the leachate
that runs out from under the pile.
     3.  Discussion
     The Agency believes that it is practical to design a
leachate detection, collection, and removal system to maintain
leachate depth at one foot or less, except perhaps temporarily
during  severe storms.  The specifications presented here,
judiciously applied, are expected to accomplish that requirement
     The minimum thickness (30 centimeters or 12 inches) of
the drainage layer is designed to allow sufficient head to
promote drainage.  The two percent minimum slope is also

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designed to promote drainage.  In most cases, the Agency
believes thicker drainage layers and greater slopes will
be selected by owners and operators to maximize the efficiency
of the leachate detection, collection, and removal system.
The hydraulic conductivity of not less than 1 X 10~3 cm/sec
was chosen because materials widely used as drainage media
are typically at least that coarse.  Additionally, where a
soil or admixed liner is used under the leachate detection,
collection, and removal system, the specification provides
four orders of magnitude difference between the drainage
layer and the soil (clay) or admixed liner (which should
have a hydraulic conductivity of not more than 1 X 10-7
cm/sec).  Data available to the Agency show a significant
increase in the efficiency of drainage when a four order of
magnitude difference exists.
   Drainage tile diameter and spacing are important because
they affect the head which builds up on the bottom liner between
the tiles.  The closer the tiles are together, the less the
head.  Also, the tile diameter should be large enough to
efficiently carry off the collected leachate.  Since the
philosophy for all aspects of liner design is to minimize
liquid transmission through the liner system, the head on
the liner should be minimized.  But the spacing and size of
the tile system necessary to accomplish this depends on
other characteristics of the drainage layer (e.g., media
hydraulic conductivity) and on the impingement rate of liquids

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which is a function of precipitation.  The Agency is therefore
not specifying minimum tile spacing or size in this guidance.
However, EPA believes that a design incorporating 4 in.
diameter tiles on 50 to 200 foot (15 to 60 meter) centers
will effectively minimize head on the liner systems.  The
owner or operator should demonstrate through appropriate
design calculations in his application that the one foot head
requirement is being or will be achieved.
   The leachate detection, collection, and removal system
should also be overlain by a graded granular or synthetic fabric
filter.  The purpose of this is to prevent clogging of the pores
in the drainage layer of the collection system by infiltration
of fines from the waste.  If a granular filter is used, it is
important that the relationship of grain sizes of the filter
medium and the drainage layer be appropriate if the filter is
to fulfill its function to prevent clogging of the drainage
layer and not contribute to clogging.  The guidance specifies
a criterion for this purpose which is widely used in construction
to prevent clogging (binding) of drainage media.   The criterion
was developed by the U.S. Army Corps of Engineers and is used
in their engineering manuals.
     The waste in many piles will be highly porous.  In these
cases, a one foot head will not develop because the percolating
leachate will simply move laterally to the edge of the pile
without mounding significantly.  In this case, no special
collection pipes or other structures may be necessary.  Where

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such piles are located at OP above grade,  the  run-off control
system required by the regulations plus  the  liner  itself may
function as the required leachate detection, collection, and
removal system.  Small piles of coarse materials on admixed
bases with curbs and sloped drain will often comply in this way.
D.  Liner Specifications
     1.  The Regulations
     As discussed in Section B of this guidance, waste pile
liners must be designed and constructed  to prevent release
of hazardous constituents to surrounding soils during the
life of the pile.  To accomplish this, liners  or bases must
be constructed of materials which have appropriate chemical
properties and strength, and which are sufficiently thick to
prevent failure due to physical contact with the waste and
leachat-e present at the facility and climatic  conditions in
the area.  Liners must also be able to withstand the stress
of installation and daily operation and be resistant to
failure due to pressure gradients, including static head and
external hydrogeologic forces.  To provide additional protection
againat failure due to pressure gradients above and below
the liner system, liners must be placed on a foundation or
base capable of providing support.
     2.  Guidance
     Section B of this guidance identifies those liner systems
the Agency believes are appropriate for waste piles, based on
length of service of the waste pile.   This section provides
                                /Z.

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further detail on the acceptable specifications for such
liner systems.
    ~ (a)  Synthetic liners should:
     (1)  Consist of at least a 30 mil membrane that is
chemically resistant to the waste managed and the leachate
generated at the waste pile.  In Judging chemical compatibility
of wastes and membranes, the Agency will consider appropriate
historical data, demonstrations involving theorectical chemistry
and actual test data.  Testing of chemical resistance of
liners should be performed using either the EPA test method
attached or an equivalent test method.
     (11)  Be protected from damage from above and below the
membrane by at least 15 centimeters (6 Inches) of bedding
material no coarser than Unified Soil Classification System
(USCS), sand (SP) and which is free of rock, fractured stone,
debris, cobbles, rubbish, roots, and sudden changes in grade.
Leachate detection,, collection, and removal systems, soil
(clay) liners,, or natural in situ soils may serve as bedding
materials when in direct.contact with synthetic liners if they
meet the requirements specified herein.
     (b)  Soil liners should:
     (1)  Consist of at least 60 centimeters (24 inches) of
natural or recompacted eraplaced soil (e.g., clay) with a
saturated hydraulic conductivity not more than 1 x 10~?
cm/sec.  Saturated hydraulic conductivity testing should be

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equivalent.
     (11)  Have a saturated hydraulic conductivity which is
not increased beyond 1 x 10-7 cm/sec as a result of contact
with the waste and leachate generated at the waste pile.
Testing of the effect of leachate on soil liner hydraulic
conductivity should be performed using either the EPA test
method attached or an equivalent test method.
    (iii)  Have no lenses, cracks, channels, root holes, or
other structural imperfections that can increase the nominal
hydraulic conductivity of the liner above 1 x lO"? cm/sec, and
      (iv)  Where recompacted emplaced soil liners are used,
be placed in lifts not exceeding 15 centimeters (6 inches)
before compaction to maximize the effectiveness of compaction.
     (c)  Single soil liners (i.e., those not used in
conjunction with a synthetic liner) should:
     (i)  Have a sufficient thickness of natural or recompacted
emplaced soil to contain the waste (i.e., no fluid flow moves
beyond the liner) during the facility's operating life; the
necessary thickness being determined by using the following
formula:
where :
     d  = necessary thickness of soil (feet)
     Q  m total porosity
     k  * hydraulic conductivity (ft/yr)
     h  » maximum fluid head on the base (feet)

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     h  = maximum fluid head on the base (feet)

     t  = pile life from start-up through closure (years);

     (ii)  Have a hydraulic conductivity which is not increased

beyond that used in the calculation as a result of contact

with the waste managed and leachate generated at the pile.

Testing of the effect of leachate on soil liner hydraulic

conductivity should be performed using either the EPA test

method attached or an equivalent test method.  A copy of the

relevant method is included in the Appendix to this document.

     (ill)  Have no lenses, cracks, channels, root holes, or

other structural imperfections that can increase the nominal

hydraulic conductivity above that used in the calculation of

liner thickness; and
                                                     i
     (iv)  Where recompacted emplaced soil liners are used,

be placed in lifts not exceeding 15 centimeters (6 inches)

before compaction to maximize the effectiveness of compaction.

     (d)  Bases of admixed'materials (e.g., concrete or

asphalt) should be:

     (i)  Of a thickness that the owner or operator can

demonstrate is structurally stable (i.e., not prone to cracking

or crumbling) when used in the location and with the wastes

managed at the pile;

     (ii)  Of a sufficient thickness and of appropriate

material to contain the waste (i.e., no fluid moves beyond

the liner) during the pile's operating life;

     (iii)  Of a sufficient strength and thickness to support

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mechanical equipment used to place or remove wastes.
     3.  Discussion
     i.  Synthetic Liners
     EPA believes synthetic liners should be at least 30 mils
thick.  Thinner synthetic membrane liners are reported to
be readily damaged.  One of the primary reasons for failure of
synthetic liners is damage such as punctures, rips, and tears
occurring during installation or operation.  To help guard
against this kind of damage, it is good practice to protect
synthetic liners by a minimum of six inches of bedding material.
This will protect against punctures, tears, and rips due to
contact with sharp objects or other conditions.  The potential
for puncture is a more prevalent problem for waste piles and
landfills than it is for surface impoundments because of
the waste types and the nature of the waste placement activities,
The wastes themselves may be capable of causing damage because
they contain sharp objects or abrasives.  The act of placing
wastes sometimes causes damage, (e.g., due to dropping of
wastes, or driving of vehicles on the liner).  The top bedding
layer also protects the synthetic membrane from damage due
to exposure to sunlight and wind while it is exposed.  The
bedding layer should consist of materials which are no coarser
than sand (SP) as defined by the Uniform Soil Classfication
System (USCS).  Use of a sand layer is common practice for
protection of membranes and other delicate materials from
damage due to contact with grading equipment and materials,
sharp materials in the soil, etc.  The bedding material need

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not be-a separate layer as natural soils or the leachate
detection, collection, and removal system materials will
often meet the necessary criteria.
       The Agency had intended to incorporate the National Sanita-
tion Foundation's (NSP) standard specifications for flexible
membrane liners as part of this guidance.  This would have
provided  minimum recommendations with regard to physical
properties, construction practices, seaming tests, etc.  An
NSP committee has been studying the subject for some time, and
EPA believes that the specifications which are being developed
are reasonable and well thought out.  However, at this point,
the NSP has not formally adopted the draft standards.  Therefore,
given the possibility that they might still be changed, EPA
believes it prudent to wait for formal adoption by the NSP before
incorporating them into this guidance document.  The NSP speci-
fications are not intended to comprehensively cover the
myriad of hazardous waste applications, however.  Therefore,
the Agency believes that some augmentation of the NSF specifica-
tions is appropriate.  A few additions have been made (e.g.,
the 30 mil thickness requirement) and more may be incorporated
if experience warrants.
     ii. Soil Liners
     Soil liners will normally consist of in situ or emplaced
clay soils.  Soils should have a saturated hydraulic conductivity
of not more than 1 x 10-7 cm/sec and be at least 60 centimeters
(2 feet) thick.  To minimize the transmission of leachate,
                                /7

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the soil liner should be as tight as practical.  Many clays
                      /
can readily be recompacted to meet the specified level.  It
is not clear, however, that recompacting to meet a tighter
specification can be routinely accomplished.  In concert
with the philosophy of these designs, soil liners are meant to
minimize the movement of liquid flow through them, so that
leachate does not traverse all the way through the liner
before closure when the liner is removed.  Both tightness and
thickness of the soil are important in this regard.  However,
in any event, a minimum thickness is necessary to retain
structural stability (reduce cracking potential, etc).  Two
feet is generally accepted to be a minimum stable thickness
for recompacted clay.
     Another function of liners is to improve the efficiency
of the leachate detection, collection, and removal system.
                                              i
Synthetic membranes typically achieve virtual complete
rejection of fluids and are thus most effective.  Soil (clay)
liners do allow a small portion of the liquid reaching them
to enter the pore structure and ultimately escape.  The
tighter the clay layer, the less fluid will seep into it, and
therefore, the more fluid will be removed by the detection,
collection, and removal system.  Prom a fluid rejection
efficiency point of view, the thickness of the soil layer is
not crucial except Insofar as it affects structural stability.
Tightness is the most important characteristic.

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     When discussing the relative tightness of soils, the
term permeability is most often used.  This is a generic
term, referring to the property in general.  In this guidance,
EPA uses the more specific term —"hydraulic conductivity".
An acceptable test method for soil hydraulic conductivity
has been included in the Appendix to this document.
     In situ soil can be considered acceptable as soil liner
material provided the specifications in this guidance are
met.  Natural soil liners should be free of conduits and
channels which would convey liquids through the liner.  This
includes root holes, sand lenses, cracks, fractures, etc.
     iii. Admixed Material Liners
     The term "admixed liner" covers a multitude of materials
with widely varying physical and chemical properties.  Some
are soil like, others are rigid, and some may contain synthetic
materials.  Among the most commonly used admixed materials
used under piles are asphalt and concrete.  Both are typically
fashioned into rigid pads on which the pile is deposited.
Addition to and removal from the pile is usually by front end
loader and the rigid nature of this base is ideal for such
operations.
     Prom a containment standpoint, the important features of
an admixed liner are much the same as for soil liners; i.e.,
the permeability and thickness of the liner or pad must be
such that the leachate will not pass through the liner prior
to closure when the pad is removed.  Proper function in this

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and liner materials but recognizes that historic data (e.g. results
elsewhere with similar wastes) or theorectical chemistry may
provide sufficient information in some cases.  Data currently
available to EPA indicate that the following combinations of
waste types and liner materials are often incompatible:
     (a)  Chlorinated solvents tend to dissolve polyvlnyl.
chloride (PVC).
     (b)  Chlorosulfonated polyethylene can be dissolved by
aromatic hydrocarbons.
     (c)  Clays may exhibit high permeability when exposed to
concentrated organics,, especially organics of high and low pH.
     (d)  Asphaltic materials may dissolve in oily wastes.
     (e)  Concrete and lime based materials are dissolved by.
acids.
     The Agency is currently developing a more comprehensive
summary of .waste/liner compatibility information which will
be included in a later edition of this document.
     An acceptable test method for evaluating waste/liner
compatibility is included in the Appendix to this document.
The test method exposes a liner sample to the waste or leachate
encountered at the pile.  After exposure, the liner sample
is tested for important characteristics—saturated hydraulic
conductivity in the case of soil liners; strength (tensile,
tear, and puncture), weight loss, and hydraulic conductivity
in the case of synthetics.  The Agency considers any significant
deterioration in any of the measured properties to be evidence
of incompatibility unless a convincing demonstration can be

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made that the deterioration exhibited will not impair the
integrity of the liner over the life of the pile.  Even
though the tests may show the amount of deterioration to be
relatively small, the Agency is concerned about the cumulative
effects of exposure over very much longer periods than those
actually tested.
     Once the NSF strength specifications previously discussed
have been published, EPA plans to incorporate them in
conjunction with the compatibility method for synthetic liners -
attached, in an improved method of evaluating liner compatibility,
While the Agency does not want to prejudge how this may be
done, one possible approach might be to extrapolate the
strength curves developed by the test method to the expected
life of the facility.  The expected strength at- that time
could then be compared against minimal acceptable strength
levels, e.g. the NSP strength specifications or some acceptable
fraction of them.  The Agency is interested in comments,
suggestions, and data on the subject of evaluating strength
loss on exposure to chemical leachates.

     E.  Waste Piles Eligible for'Exemption from Subpart P
     1.  The Regulations
     Sections 264.252 and 264.253 contain exemptions from
Subpart P (the ground water protection standard and associated
monitoring and remedial action requirements) for certain
waste piles.  Eligible waste piles must be located above the

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water table, designed and operated with a leachate detection
collection and removal system and either (1) a double liner
system designed and constructed to prevent discharge during
the life of the waste pile, with a leak detection system
between the liners; or (2) a base, designed and operated to
prevent discharge during the life of the pile, underlying
and in contact with the pile, which is of sufficient strength
and thickness to allow waste to be removed from the pile to
expose the liner surface for inspection without causing
damage to the base.
     2.  Guidance
     (a)  Owners and operators of waste piles designed as
follows are eligible for an exemption from Part 264, Subpart P
in accordance with §264.252:
     (1)  Waste piles which are designed with an under-
liner system consisting of the following, as a minimum and
located wholly within the unsaturated zone (i.e., above, the
seasonal high water table) should have:
     (i)  A primary liner, and
     (ii)  A leachate detection, collection, and removal system
meeting the specifications contained in §C(2) of this guidance,
and
     (iii) A secondary synthetic liner meeting the specifications
contained in §D (2)(a) of this guidance, and
     (v)  A leak detection system between the liners, and
     (vi) For waste piles which will not complete closure for

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30 or more years In accordance with the closure plan
required by §264.112, a tertiary soil liner meeting the
specifications contained in §D(2)(b).
     (b)  Owners and operators of waste piles designed as
follows are eligible for an exemption from Part 264, Subpart
P in accordance with §264.253:
     (1) Waste piles which are designed with a underllner system
consisting of the following, as a minimum and located wholly within
the unsaturated zone (i.e., above the seasonal high water
table) should have:
     (i) A base of admixed materials meeting the specifications
contained in §D (2)(d) of this guidance, and
     (ii)  A leachate detection, collection, and removal
system.
     3.  Discussion
     Sections 264.252 and 264.253 of Subpart L contain
descriptions of two types of waste piles eligible for an
exemption from Subpart P of Part 264.  Because that description
is essentially performance oriented with only a general
description of specific eligible designs, this guidance
offers more specificity as to what the Agency considers
adequate to meet the performance requirements.
     As stated in the preamble to Subpart L, the Agency generally
does not consider waste piles designed with single soil liners or
bases to be appropriate for an exemption from Subpart P.
Likewise, waste piles with a single synthetic liner are not

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eligible for an exemption from Subpart P.
     The monitoring program incorporated in Subpart P serves
as a backup to the design and operating performance requirements
of this section by detecting unexpected ground-water contamination
from the pile.  Before the provisions for Subpart P can be
safely waived, an alternate monitoring system must be in
place to identify breaches in the containment system before
ground-water contamination can occur.  The Agency has identified
two appropriate designs in the regulations which provide early
warning monitoring of the containment system.  Double lined
waste piles with leachate detection, collection, and removal
systems will be able to detect a breach in the primary liner
if leachate is detected between the liners by the leak detection
system.  Waste piles with single bases of admixed materials
can detect breaches by removal of wastes and physical inspection
of the base.
     Double lined waste piles will usually have synthetic
liners.  If they will operate for more than 30 years the
bottom synthetic liner should be underlain by a clay liner
Since waste piles are storage facilities, owner or operator
may chose to use only soil or admixed liners, properly designed
to retard movement through them during the life of the unit,
for one or both liners.  However, since leakage of any fluid
into the leak detection system will be considered evidence
that one of the liners has failed and since the consequences
of liner failure are substantial, EPA expects most owners or

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operators to chose the more impermeable synthetics when
designing double lined facilities.
     The leak detection system between the liners can conceivably
be constructed in a variety of ways including the use of
advanced instrumentation.  A relatively simple leak detection
system, depending on gravity flow, is very similar to a leachate
detection, collection, and removal system and can be acceptably
constructed in accordance with the guidance in Section C of
this document.
     Single bases from which wastes can be removed for the
purpose of physical inspection of the base will generally be
constructed of concrete or asphalt and should meet the
specifications of Section D.  In designing and constructing
the pad or base, the owner or operator should carefully
consider the ability of the base to withstand chemical attack
by leachates and to bear the load and withstand the other
forces associated with placing and removing the waste because
if deterioration of the base is in evidence during routine
Inspections, he must either repair the base or lose his
exemption from Subpart P.
     Single base waste piles must be designed and constructed
with a leachate detection, collection and removal system.
However, in many cases, the leachate detection, collection,
and removal system described in Section C of this guidance
may not be appropriate for such piles since such piles must
be periodically cleared to allow for inspection of the base.

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           APPENDIX A
METHODS FOR DETERMINING SATURATED
HYDRAULIC CONDUCTIVITY, SATURATED
   LEACHATE CONDUCTIVITY, AND
     INTRINSIC PERMEABILITY

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For single base waste piles constructed of admixed materials,
the run-off control system in combination with the liner itself,
may be sufficient for the purpose of leachate collection and
removal.
                          2.7

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                       TABLE OF CONTENTS

                                                           Page

1.0  INTRODUCTION	   1-1

     1.1  SCOPE AND APPLICATION	   1-1

     1.2  DEFINITIONS	   1-5

          1.2.1  Units	   1-5
          1.2.2  Fluid potential or head	   1-6
          1.2.3  Hydraulic potential or head	   1-6
          1.2.4  Hydraulic conductivity 	   1-6
          1.2.5  Fluid conductivity 	   1-7
          1.2.6  Leachate conductivity  	   1-8
          1.2.7  Aquifer	   1-8
          1.2.8  Confining layer	   1-8
          1.2.9  Transraissivity	   1-8

     1.3  TEMPERATURE AND VISCOSITY CORRECTIONS 	   1-9

     1.4  INTRINSIC PERMEABILITY  	  1-10

     1.5  RANGE OF VALIDITY OF DARCY'S LAW	1-10

     1.6  METHOD CLASSIFICATION	  1-12

2.0  LABORATORY METHODS 	   2-1

     2.1  SAMPLE COLLECTION FOR LABORATORY METHODS  .  .  .   2-1

     2.2  CONSTANT-HEAD METHODS 	   2-1

     2.3  FALLING-HEAD METHODS  	   2-3

     2.4  GENERAL TEST CONSIDERATIONS 	   2-5

          2.4.1  Fluid Supplies to be Used	   2-5
          2.4.2  Pressure and Fluid Potential Measurement   2-6

     2.5  CONSTANT-HEAD TEST WITH CONVENTIONAL
          PERMEAMETER   	   2-6

          2.5.1  Applicability	   2-6
          2.5.2  Apparatus	   2-7
          2.5.3  Sample Preparation 	   2-7
          2.5.4  Test Procedure	   2-9
          2.5.5  Calculations	   2-10

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            TABLE OF CONTENTS (Continued)
2.6  FALLING-HEAD TEST WITH CONVENTIONAL
     PERMEAMETER   	2-10

     2.6.1  Applicability	2-10
     2.6.2  Apparatus	2-10
     2.6.3  Sample Preparation 	  2-11
     2.6.4  Test Procedure	2-11
     2.6.5  Calculations	2-11

2.7  MODIFIED COMPACTION PERMEAMETER METHOD  ....  2-12

     2.7.1  Applicability	2-12
     2.7.2  Apparatus	  2-12
     2.7.3  Sample Preparation	  2-12
     2.7.4  Test Procedure	2-13
     2.7.5  Calculations	2-13

2.8  TRIAXIAL-CELL METHOD WITH BACK PRESSURE ....  2-13

     2.8.1  Applicability	2-13
     2.8.2  Apparatus	2-15
     2.8.3  Sample Preparation ...........  2-15
     2.8.4  Test Procedure	  2-15
     2.8.5  Calculations	2-19

2.9  PRESSURE-CHAMBER PERMEAMETER METHOD 	  2-19

     2.9.1  Applicability	2-19
     2.9.2  Apparatus	2-19
     2.9.3  Sample Preparation 	  2-19
     2.9.4  Test Procedure	2-21
     2.9.5  Calculations	2-21

2.10 SOURCES OF ERROR FOR LABORATORY TEST FOR
     HYDRAULIC CONDUCTIVITY  	  2-21

2.11 LEACHATE CONDUCTIVITY USING LABORATORY METHODS   2-23

     2.11.1 Applicability  	  2-23
     2.11.2 Leachate Used	2-24
     2.11.3 Safety 	  2-24
     2*11.4 Procedures . 	  2-25
     2.11.5 Apparatus  	  2-25
     2.11.6 Measurements	  2-25
     2.11.7 Calculations 	 ...  2-26
                         ii

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                 TABLE OF CONTENTS (Continued)

                                                           Page
3.0  FIELD METHODS	   3-1

     3.1  WELL-CONSTRUCTION CONSIDERATIONS  	   3-2

          3.1.1  Well Installation Methods	   3-2
          3.1.2  Wells Requiring Well Screens 	   3-3
          3.1.3  Wells Not Requiring Well Screens ....   3-5

     3.2  WELL DEVELOPMENT	   3-5

     3.3  DATA INTERPRETATION AND TEST SELECTION
          CONSIDERATIONS  	   3-6

     3.4  SINGLE WELL TESTS	   3-8

          3.4.1  Method for Moderately Permeable            . -
                 Formations Under Confined Conditions .  .   3-8
          3.4.2  Methods for Extremely Tight Formations
                 Under Confined Conditions  	   3-13
          3.4.3  Methods for Moderately Permeable
                 Materials Under Unconfined
                 Conditions	   3-17

     3.5  MULTIPLE WELL TESTS   	3-22

     3.6  ESTIMATES OF HYDRAULIC CONDUCTIVITY FOR
          COARSE-GRAINED MATERIALS  	   3-22

     3.7  CONSOLIDATION TESTS	   3-25

     3.8  FRACTURED MEDIA   	3-26

4.0  CONCLUSION	   4-1

5.0  REFERENCES	   5-1

6.0  APPENDIX A	   6-1
                              iii

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                 TABLE OF CONTENTS (Continued)


                        LIST OF TABLES
Table No.                                                  Page
   A        HYDRAULIC AND LINER CONDUCTIVITY
            DETERMINATION REQUIREMENTS FOR SURFACE
            IMPOUNDMENTS, WASTE PILES, AND LANDFILL
            COMPONENTS, AS CITED IN RCRA GRUIDANCE
            DOCUMENTS AND DESCRIBED IN SW-846    ....    1-2

   B        SUMMARY OF PUBLISHED DATA ON POTENTIAL
            ERRORS IN USING DATA FROM LABORATORY
            PERMEABILITY TESTS ON SATURATED SOILS  .  .  .   2-22

   C        HYDRAULIC CONDUCTIVITIES ESTIMATED FROM
            GRAIN-SIZE DESCRIPTIONS  	   3-24
                        LIST OF FIGURES
Figure No*

    1       PRINCIPLE OF THE CONSTANT HEAD METHOD  ...   2-3

    2       PRINCIPLE OF THE FALLING HEAD METHOD   .  .  .   2-4

    3       APPARATUS SETUP FOR THE CONSTANT HEAD
            AND FALLING HEAD METHODS	   2-8

    4       MODIFIED COMPACTION PERMEAMETER	  2-14

  ,  5       SCHEMATIC DIAGRAM OF TYPICAL TRIAXIAL
            COMPRESSION APPARATUS FOR
            HYDRAULIC CONDUCTIVITY TESTS WITH
            BACK PRESSURE	2-15

    6       PRESSURE CHAMBER FOR HYDRAULIC
            CONDUCTIVITY 	  2-20

    7       GEOMETRY AND VARIABLE DEFINITION FOR
            SLUG TESTS IN CONFINED AQUIFERS  ......  3-10

    8       SCHEMATIC DIAGRAM FOR PRESSURIZED
            SLUG TEST METHOD   	3-15

    9       VARIABLE DEFINITIONS FOR SLUG TESTS
            IN UNCONFINED MATERIALS	  3-18

   10       CURVES DEFINING COEFFICIENTS A, B, AND C
            to L/rw	3-21
                              iv

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                           METHOD SW-846

               SATURATED HYDRAULIC CONDUCTIVITY,
             SATURATED LEACHATE CONDUCTIVITY, AND
                    INTRINSIC PERMEABILITY
                       1.0   INTRODUCTION


1.1  SCOPE AND APPLICATION

This section presents methods available to hydrogeologists  and

geotechnical engineers for determining the saturated  hydraulic

conductivity of earth materials  and conductivity of soil  liners

to leachate, as outlined by  the  Part  264 permitting rules for

hazardous-waste disposal facilities.  In addition, a  general

technique to determine intrinsic permeability  is provided.  A

cross reference between the  applicable parts of the RCRA

Guidance Documents and associated Part 264 Standards  and  these

test methods is provided by  Table A.


Part 264 Subpart F establishes standards for ground-water

quality monitoring and environmental  performance.  To

demonstrate compliance with  these standards, a permit applicant

must have knowledge of certain aspects of the  hydrogeology

at the disposal facility, such as hydraulic conductivity, in

order to determine the compliance point and monitoring well

locations and in order to develop remedial action plans when

necessary.


In this report, the laboratory and field methods that are con-

sidered the most appropriate to  meeting the requirements  of

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                                                                1-2
                             TABLE A

         HYDRAULIC AND LINER CONDUCTIVITY DETERMINATION
                 METHODS FOR SURFACE IMPOUNDMENT
          WASTE PILE, AND LANDFILL COMPONENTS, AS CITED
       IN RCRA GUIDANCE DOCUMENTS    AND DESCRIBED IN SW-846
Surface Impoundments
Guidance
Associated Regulation
Corresponding
   SW-846
   Section
Soil liner hydraulic
conductivity
Guidance section D(2)(b)(1)
and D(2)(c)(1)/Section
264.221(a),(b)
      2.0
Soil liner leachate
conductivity
Guidance section D(2) (b)(2)
and D(2) (c) (2)
Leak detection system
Guidance section C(2)(a)/
Section 264.222
                                                               2.0
Final cover drain
layer


Final cover low
permeability layer
Guidance section E(2)(d) (I)/
Section 264.228
Guidance section E(2)(e)(2)(A)/
Section 264.228
      2.0


      2.0
General Hydrogeologic
site investigation
264 subpart F
      3.0
  RCRA Guidance Document:  Surface Impoundments, Liner Systems,
  Final Cover, and Freeboard Control.  Issued Julyv 1982.

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                                                              1-3
     Waste Piles
   Guidance Cite—'
   Associated Regulation
Correspond!*
   SW-846
   Section
Soil liner hydraulic
conductivity
Guidance section D(2)(b)(i)
and D(2) (c) (i)/
Section 264.251(a)(1)
      2.0
Soil liner leachate
conductivity
Guidance section D(2)(b)(ii)
and D(2)(c)(ii)
      2.11
Leak Detection
System
Guidance section C(2)(a)/
Section 264.252 (a)
      2.0
Leachate collection
and renewal system
Guidance section C(2)(a)/
Section 264.251 (a) (2)
      2.0
General hydrogeologic
site investigation
264 subpart F
      3.0
—'RCRA Guidance Document:
  Issued July, 1982•
  Waste Pile Design, Liner Systems,

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                                                                 1-4
     Landfills
 Guidance Cite—'
 Associated Regulation
Corresponding
   SW-846
   Section
Soil liner hydraulic
conductivity
 Guidance section D(2)(b)(I)/
 Section 264.301(a)(1)
      2.0
Soil liner leachate
conductivity
 Guidance section D(2)(b)(2)
      2.11
Leak detection
system
 Guidance section C(2)(a)/
 Section 264.302(a)(3)
      2.0
Leachate collection and   Guidance section C(2)(a)/
removal system            Section 264.301(a) (2)
                                      2.0
Final cover drain
layer
Guidance section E(2)(d)(I)/
Section 264.310(a)(b)
      2.0
Final cover low
permeability layer
Guidance section E(2)(e)(2)(A)
Section 264.310(a)(b)
      2.0
General hydrogeologic    264 subpart F
site investigation
                                      3.0
— RCRA Guidance Document:  Landfill Design, Liner  Systems  and
  Final Cover.  Issued July, 1982.

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                                                             1-5



Part 264 are given in sufficient detail  to provide  an


experienced hydrogeologist or geotechnical engineer with  the


methodology required to conduct the  tests.  Additional  labora-


tory and field methods that may be applicable  under certain


conditions are included by providing reference  to standard


texts and scientific journals.



Included in this report are descriptions of field methods con-


sidered appropriate for estimating saturated hydraulic  conduc-


tivity by single well or borehole tests.  The  determination of


hydraulic conductivity by pumping or injection  tests is not


included because the latter are considered appropriate  for  well


field design purposes but may not be appropriate for economi-
                                                          \  - v

cally evaluating hydraulic conductivity  for the purposes  set


forth in Part 264 Subpart F.



EPA is not including methods for determining unsaturated


hydraulic conductivity at this time  because the Part 264  per-


mitting standards do not require such determinations.


1.2    DEFINITIONS


This section provides definitions of terms used in  the  remainder


of this report.  These definitions are taken from U.S.  Govern-


ment publications when possible.



1.2.1  Units;  This report uses consistent units in all


equations.  The symbols used are:


             Length = L,


             Mass   = M, and


             Time   = T.

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                                                             1-6
1.2.2  Fluid Potential or  head  (h)  is  a measure  of the poten-
tial energy required  to move  fluid  from a  point  in the porous
medium to a reference point.  For virtually all  situations
expected to be found  in disposal sites and in ground-water
systems, h is defined by the  following equation:

          h - hp + hz                                        (1)
where
          h  is the total  fluid potential, expressed as
             a height of fluid above a reference datum, L;
          hp is the pressure  potential caused by the
             weight of fluid  above  the point in  question, L.
          hp is defined by hp = P/pg,
where
          P  is the fluid  pressure  at  the  point  in question,
             ML-J-T-2,
          p  is the fluid  density at the prevailing tempera-
             ture, ML~3,
          g  is the acceleration of gravity, LT~2, and
          hz is the height of the point in question above
             the reference datum, L.
          By knowing hp and hz at two  points along a flow path
          and by knowing the  distance  between these points,
          the fluid potential gradient can be determined.

1.2.3  Hydraulic potential or head  is  the  fluid  potential when
water is the fluid.
1.2.4  Hydraulic conductivity is the fluid conductivity when
water is the fluid.  The generic term, fluid conductity, is
discussed below in 1.2.5.

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                                                             1-7
1.2.5  Fluid conductivity  is  defined  as  the volume of fluid at
the prevailing density  and dynamic  viscosity that will move in
a unit time under a  unit fluid  potential gradient through a
unit area measured at right angles  to the direction of flow.
It is a property of  both the  fluid  and the porous medium as
shown by the following  equation:
         K  •      ,                                          (2)
               u
where

         K  is  the  fluid  conductivity,  LT~1;
         k  is the  intrinsic permeability,  a property of
            the porous medium  alone,  L~2;
         y  is the dynamic viscosity of  the  fluid  at  the
            prevailing temperature, ML~1 T~l.
The fluid conductivity of a porous material  is  also defined by
Darcy's law, which  states that the fluid flux  (q)  through a
porous medium  is proportional  to  the  first  power of the fluid
potential across the unit area:
         q -   - Kl,                                         (3)
             A
where
         q » the specific  fluid  flux,  LT~1,
         Q is the volumetric  fluid  flux,  L3T~1,
         A is the cross-sectional area, L2,  and
         I is the fluid potential gradient,  L°.

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                                                             1-8
Oarcy's law provides the basis  for  all methods  used  to deter-
mine hydraulic conductivity discussed  in  this report.   The
range of validity of Darcy's  law  is discussed in  Section 1.4
(Lohman, 1972).

1.2.6  Leachate conductivity  is the fluid conductivity when
leachate is the fluid.

1.2.7  Aquifer is a geologic  formation, group of  formations, or
part of a formation capable of yielding a significant  amount of
ground water to wells or springs  (40 CFR  260.10).

1.2.8  Confining layer is a body  of impermeable material stra-
tigraphically adjacent to one or  more  aquifers.   In  nature,
however, its hydraulic conductivity may range from nearly zero
to some value distinctly lower  than that  of  the aquifer. Its
conductivity relative to that of  the aquifer it confines should
be specified or indicated by  a suitable modifier, such as
slightly permeable or moderately  permeable (Lohman,  1972).
1.2.9  Transmissivity, T  [L^, T"^l ,  is  the  rate  at which  water
of the prevailing kinematic viscosity is  transmitted  through  a
unit width of the aquifer under a  unit  hydraulic gradient.
Although, spoken of as a property of  the aquifer,  the  term also
includes the saturated thickness of  the aquifer  and the proper-
ties of the fluid.  It is equal to an integration of  the
hydraulic conductivities across the  saturated part of the
aquifer perpendicular to the flow  paths (Lohman,  1972).

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                                                             1-9
1.3    TEMPERATURE AND VISCOSITY CORRECTIONS
By using Equation 2, corrections to conditions different  from
those prevailing during the test can be made.  Two types  of
corrections can commonly be made:  a correction for a  tem-
perature that varies from the test temperature, and a  correc-
tion for fluids other than that used for the test.  The tem-
perature correction is defined by:
            m Kt Ut Pf ,                                    (4)
                 Wf Pt
where
         the subscript f refers to field conditions, and
         t refers to test conditions.

Most temperature corrections are necessary because of  the
viscosity dependence on temperature.  Fluid density variations
caused by temperature changes are usually very small for most
liquids.  The temperature correction for water can be  signifi-
cant.  A temperature decrease from 75°C to 10°C results  in  a
68 percent reduction in viscosity and hence hydraulic  conduc-
tivity.  Equation 4 can also be used to determine hydraulic
conductivity if fluids other than water are used.  It  is
assumed, however, when using Equation 4 that the fluids  used
do not alter the intrinsic permeability of the porous  medium
during the test.  Experimental evidence exists that shows that
this alteration occurs with a wide range of organic solvents
(Anderson and Brown, 1981).  Consequently, it is recommended

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                                                            1-10
that tests be run using  fluids,  such  as  leachates,  that might
occur at each particular disposal  site.   Special  considerations
for using non-aqueous  fluids  are given in Section 3.3  of this
report.

1.4    INTRINSIC PERMEABILITY
Rearrangement of Equation  2 results in a definition of intrin-
sic permeability.
                            -   •                              (5)
                          pg
Since this is a property of  the medium alone,  if  fluid  proper-
ties change, the fluid conductivity must also  change  to keep
the intrinsic permeability a constant.   By  using  measured  fluid
conductivity, and values of  viscosity and density for the  fluid
at the test temperature, intrinsic permeability can be  determined,

1.5    RANGE OF VALIDITY OF  DARCY'S LAW
Determination of fluid conductivities using both  laboratory  and
field methods requires assuming the validity of Darcy's law.
Experimental evidence has shown that deviations from  the linear
dependence of fluid flux on  potential gradient exist  for both
extremely low and extremely  high gradients  (Hillel, 1971;
Freeze and Cherry, 1979).  The low gradient limits are  the
result of the existence of threshold gradients required to ini-
tiate flow ( Swartzendruber ,  1962).  The  upper  limits  to the
validity of Darcy's law can  be estimated  by the requirements

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                                                            1-11
that the Reynolds number, Re,  in most  cases  be kept  below  10
(Bear, 1972).  The Reynolds number  is  defined by:
                 pqd
where
            Re = ^  ,                                       (6)
                  y
            d is some characteristic dimension  of  the
              system, often  represented  by  the  median  grain
              size diameter,  DSQ,  (Bouwer,  1978),  and
            q is the fluid flux per unit area,  LT"1.
For roost field situations,  the  Reynolds  number  is  less  than
one, and Darcy's law  is valid.  However,  for  laboratory tests
it may be possible to exceed  the  range of validity by the  impo-
sition of high potential gradients.  A rough  check on accep-
table gradients can be made by  substituting Darcy's law in
Equation 6 and using  an upper limit of 10 for Re:
                         ,                                    (7)
                 pKDso
where
             K is the approximate value of  fluid  conductivity
               determined at gradient  I.

A more correct check on  the validity of Darcy's law  or  the
range of gradients used  to determine fluid  conductivity would
be to measure the conductivity at three different gradients.
If a plot, of fluid flux  versus gradient is  linear, Darcy's  law
can be considered to be  valid for the  test  conditions.

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                                                            1-12
1.6    METHOD CLASSIFICATION
This report classifies methods  to  determine  fluid conductivity
into two divisions:   laboratory and  field  methods.   Ideally,
compliance with  the Part  264  disposal  facility requirements
should be evaluated by using  field methods that test the
materials under  in-situ conditions whenever  possible.   In
general, field methods can  usually provide more representative
values than laboratory methods  because they  test a larger
volume of material, thus  integrating the effects of macro-
structure and heterogeneities.   However, field methods  pre-
c intly available to determine the  conductivity of compacted -
fine-grained materials in reasonable times require the  tested
interval to be below  a water  table,  to be  fairly thick,  or to
require excavation of the material to  be tested at some  point
in the test.  The integrity of  liners  and  covers should  not be
compromised by the installation of boreholes or piezometers
required for the tests.   These  restrictions  generally result  in
the requirement  to determine  the fluid conductivity of  liner
and cover materials in the  laboratory.  The  transfer value of
laboratory data  to field  conditions  can be maximized for liners
and covers because it is  possible  to reconstruct relatively
accurately the desired field  conditions in the laboratory.
However, field conditions that  would alter the values deter-
mined in the laboratory need  to be addressed in permit  applica-
tions.  These conditions  include those that  would increase con-
ductivity by the formation  of microcracks  and channels  by
repeated wetting and  drying,  and by  the penetration of  roots.

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                                                            1-13
Laboratory methods are categorized  in  Section  2.0  by  the
methods used to apply the fluid potential gradient across  the
sample.  The discussion of  the theory, measurement, and com-
putations for tests run under constant and  falling-head con-
ditions is followed by a detailed discussion of  tests using
specific types of laboratory apparatus and  the applicability of
these tests to remolded compacted,  fine-grained  uncompacted,
and coarse-grained porous media.  Section 2.3  provides a
discussion of the special considerations for conducting
laboratory tests using non-aqueous  permeants.  Section 2.10
gives a discussion of the sources of error  and guidance for
establishing the precision  of laboratory tests.

Field methods are discussed in Section 3.0  and are limited to
those requiring a single bore hole  or  piezometer.   Methods
requiring multiple bore holes or piezometers and areal methods
are included by reference.  Because of the  difficulties in
determining fluid conductivity of in-place  liner and  cap
materials under field conditions without damaging  their
integrity, the use of field methods for fine-grained  materials
will be generally restricted to naturally occurring materials
that may serve as a barrier to fluid movement.   Additional
field methods are referenced that allow determination of
saturated hydraulic conductivity of the unsaturated materials
above the shallowest water  table.   General  methods for frac-
tured media are given in Section 3.8.

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                                                            1-14
A discussion of the important considerations  in well  installa-
tion, construction, and development is  included as  an introduc-
tion to Section 3*0.

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                                                             2-1


                    2.0  LABORATORY METHODS


2.1  SAMPLE COLLECTION FOR LABORATORY METHODS

To assure that a reasonable assessment  is made of  field  con-

ditions at a disposal site, a site investigation plan  should be

developed to direct sampling and analysis.  This plan  generally

requires the professional judgment of an experienced hydro-

geologist or geotechnical engineer.  General guidance  is pro-

vided for plan development in the Guidance Manual  for

Preparation of a Part 264 Land Disposal Facility Permit

Application (EPA, in press).  The points listed below  should

be followed:

o  The hydraulic conductivity of a soil liner should be  deter-
   mined either from samples that are processed to simulate
   the actual liner, or from an undisturbed sample of  the
   complete liner.

   To obtain undisturbed samples, the thin-walled  tube sampling
   method (ASTM Method # D1587-74) or a similar method may be
   used.  Samples representative of each lift of the liner
   should be obtained, and used in the analyses.   If actual
   undisturbed samples are not used, the soil used in  liner
   construction must be processed to represent accurately
   the liner's initial water content and bulk density.   The
   method described in Section 2.7.3 or ASTM Method #D698-70
   (ASTM, 1978) can be used for this purpose.

o  For purposes of the general site investigation,  the general
   techniques presented in ASTM method #0420-69 (ASTM, 1978)
   should be followed.  This reference establishes practices
   for soil and rock investigation and sampling, and incorporates
   various detailed ASTM procedures for investigations,  sampling,
   and material classification.


2.2  CONSTANT-HEAD METHODS

The constant-head method is the simplest method to determine

hydraulic conductivity of saturated soil samples.   The concept

of the constant-head method is schematically illustrated in

-------
                                                             2-2
Figure 1.  The inflow of  fluid  is  maintained  at a constant
head (h) above a datum and outflow (Q)  is  measured as a func-
tion of time  (t).  Using  Darcy's law,  the  hydraulic conduc-
tivity can be determined  using  the following  equation after the
outflow rate has become constant:

               K - QL/hA,                                   (8)
where
               K » hydraulic  conductivity,
               L - length of  sample,  L
               A » cross-sectional  area  of  sample,  L2
               Q » outflow  rate,  L^T*
               h » fluid head difference across the sample, L

Constant-head methods  should  be  restricted  to tests on media
                                                  *   *
having high fluid conductivity.
   x
2.3  FALLING-HEAD METHODS
A schematic diagram of the  apparatus  for the falling-head
method is shown in Figure 2.   The head of inflow fluid
decreases from h^ to h2 as  a  function of time (t) in a stand pipe
directly connected to  the specimen.   The fluid head at the
outflow is maintained  constant.   The  quantity of outflow can be
measured as well as the quantity  of inflow.   For the setup shown
in Figure 2a, the hydraulic conductivity can be determined
using the following equation:
                         log,,
                   At       io hi

-------
                                                        2-3
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-------
                                                       2-4



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-------
                                                             2-5

where
          a = the cross-sectional  area  of  the  standpipe,  L2
          A « the cross-sectional  area  of  the  specimen,  L2
          L = the length of  the  specimen,  L
          t = elapsed time from  t^ to t2,  T.

For the setup shown  in Figure  2b,  the term a/A in  Equation 9 is
replaced by 1.0.  Generally, falling-head  methods  are  applicable
to fine-grained soils because  the  testing  time can be  accelerated.

2.4    GENERAL TEST  CONSIDERATIONS
2.4.1  Fluid Supplies to be  Used
For determining hydraulic conductivity  and leachate conduc-
tivity, the supplies of permeant fluid  used should be  de-aired.
Air coming out of solution in  the  sample can significantly
reduce the measured  fluid conductivity.  Deairing  can  be
achieved by boiling  the water  supply under a vacuum, bubbling
helium gas through the supply, or  both.

Significant reductions in hydraulic conductivity can also occur
in the growth and multiplication of microorganisms present in
the sample.  If it is desirable  to prevent such growth,  a bac-
tericide or fungicide, such  as 2000 ppm formaldehyde or  1000 ppm
phenol (Olsen and Daniel, 1981), can be added  to the fluid supply.

Fluid used for determining hydraulic conductivity  in the  labora-
tory should never be distilled water.   Native  ground water from
the aquifer underlying the sampled area or water prepared to
simulate the native ground-water chemistry should  be used.

-------
                                                             2-6
2.4.2  Pressure and Fluid Potential Measurement
The equations in this report are all dimensionally  correct;
that is, any consistent set of  units may  be  used  for  length,
mass, and time.  Consequently,  measurements  of pressure  and/or
fluid potential using pressure  gages and  manometers must be
reduced to the consistent units used before  applying  either
Equation 8 or 9.  Pressures or  potentials should  be measured
to within a few tenths of one percent of  the gradient applied
across the sample.

2.5    CONSTANT-HEAD TEST WITH  CONVENTIONAL  PERMEAMETER
2.5.1  Applicability
This method covers the determination of the  hydraulic conduc-
tivity of soils by a constant-head method using a conventional
permeameter.  This method is recommended  for disturbed coarse-
                             \
grained soils.  If this method  is to be used for  fine-grained
soils, the testing time may be  prohibitively long.  This method
was taken from the Engineering  and Design, Laboratory Soils
Testing Manual (U.S. Army, 1980).  It parallels ASTM  Method
D2434-68 (ASTM, 1978).  The ASTM method gives extensive
discussion of sample preparation and applicability  and should
be reviewed before conducting constant-head  tests.  Lambe (1951)
provides additional information on sample preparation and
equipment procedures.

-------
                                                            2-8
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        (a)
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Figure 3.— Apparatus  setup for the constant head (a)
            and falling  head (b)  methods.

-------
                                                             2-7
2.5.2  Apparatus
The apparatus is shown schematically  in  Figure  3.   It  consists
of the following:

   a.   A permeameter cylinder having a  diameter  at least
        8 times the diameter of the largest particle of  the
        material to be tested,
   b.   Constant-head filter tank,
   c.   Perforated metal disks and circular wire  to support
        the sample,
   d.   Filter materials such as Ottawa  sand, coarse sand, and
        gravel of various gradations,
   e.   Manometers connected to the top  and bottom  of  the sample,
                                                             j^
   f.   Graduated cylinder, 100 ml capacity,
   g.   Thermometer,
   h.   Stop watch,           .  .
   i.   Deaired water,,
   j.   .Balance sensitive to 0.1 gram, and        ,.  -. .".- '~ '' ~
   k.   Drying oven.

2.5.3  Sample Preparation
1.  Oven-dry the specimen.  Allow it  to  cool, and weigh  to the
    nearest 0.1 g.  Record the oven-dry  weight  of material on a
    data sheet as Ws.  The amount of material should be  sufficient
    to provide a specimen in the permeameter having a  minimum
    length of about one to two times  the diameter of the specimen.
2.  Place a wire screen, with openings small enough to retain
    the specimen, over a perforated disk near the bottom of  the
    permeameter above the inlet.  The screen openings  should be
    approximately equal to the 10 percent size  of the  specimen.
3.  Allow deaired water to enter the water inlet  of the
    permeameter to a height of about  1/2 in. above  the bottom
    of the screen, taking care that no air bubbles  are trapped
    under the screen.

-------
                                                             2-9

4.  Mix the material thoroughly and place  in the permeameter to
    avoid segregation.  The material should be dropped  just  at
    the water surface, keeping the water surface about  1/2 in.
    above the top of the soil during placement.  A  funnel or a
    spoon is convenient for this purpose.

5.  The placement procedure outlined above will result  in a
    saturated specimen of uniform density  although  in a rela-
    tively loose condition.  To produce a  higher density in  the
    specimen, the sides of the permeameter containing the soil
    sample are tapped uniformly along  its  circumference and
    length with a rubber mallet to produce an increase  in
    density; however, extreme caution  should be exercised so
    that fines are not put into suspension and segregated
    within the sample.  As an alternative  to this procedure,
    the specimen may be placed using an appropriate sized
    funnel or spoon.  Compacting the specimen in layers is
    not recommended as a film of dust  may  be formed at  the
    surface of the compacted layer which might affect the
    permeability results.  After placement, apply a vacuum
    to the top of the specimen and permit water to enter the
    evacuated specimen through the base of the permeameter.  -

6.  After the specimen has been placed, weigh the excess
    material, if any, and the container.  The specimen  weight
    is the difference between the original weight of sample  and
    the weight of the excess material.  Care must be taken so
    that no material is lost during placement of the specimen.
    If there is evidence that material has been lost, oven-dry
    the specimen and weigh after the test  as a check.

7. -Level the top of the specimen, cover with a wire screen
    similar to that used at the base,  and  fill the remainder of
    the permeameter with a filter material.

8.  Measure the length of the specimen, inside diameter of the
    permeameter, and distance between  the  centers of the
    manometer tubes (L) where they enter the permeameter.


2.5.4  Test Procedure

1.  Adjust the height of the constant-head tank to obtain the
    desired hydraulic gradient.  The hydraulic gradient should
    be selected so that the flow through the specimen is lami-
    nar.  Hydraulic gradients ranging  from 0.2 to 0.5 are recom-
    mended.  Too high a hydraulic gradient may cause turbulent
    flow and also result in piping of  soils.  In general,
    coarser soils require lower hydraulic gradients.  See
    Section 1.5 for further discussion of  excessive gradients.

2.  Open valve A (see Figure 3a) and record the initial
    piezometer readings after the flow has become stable.
    Exercise care in building up heads in  the permeameter
    so that the specimen is not disturbed.

-------
                                                            2-10
3.  After allowing a few minutes  for equilibrium  conditions  to
    be reached, measure by means  of a graduated cylinder  the
    quantity of discharge corresponding  to  a given  time inter-
    val.  Measure the piezometric heads  (h^ and h2>  and the
    water temperature in the permeameter.
4.  Record the quantity of flow,  piezometer readings,  water
    temperature, and the time  interval during which the quan-
    tity of flow was measured.
2.5.5  Calculations
By plotting the accumulated quantity of  outflow versus time  on
rectangular coordinate paper,  the slope  of  the linear  portion
of the curve can be determined, and the  hydraulic conductivity
can be calculated using Equation  (8).  The  value  of h  in
Equation 8 is the difference between h^  and h2«
2.6    FALLING-HEAD TEST WITH CONVENTIONAL PERMEAMETER
2.6.1  Applicability
The falling-head test can be used  for all soil  types,  but  is
usually most widely applicable to  materials having  low per-
meability.  Compacted, remolded, fine-grained soils can be tested
with this method.  The method presented  is taken  from  the
Engineering and Design, Laboratory Soils Testing  Manual (U.S.
Army, 1980).
2.6.2  Apparatus
The schematic diagram of falling-head permeameter is shown in
Figure 3b.  The permeameter consists of  the following  equipment:
   (1)  Permeameter cylinder - a transparent acrylic cylinder
        having a diameter at least 8 times the  diameter of the
        largest particles,
   (2)  Porous disk,

-------
                                                            2-11
   (3)  Wire screen,
   (4)  Filter materials,
   (5)  Manometer,
   (6)  Timing device, and
   (7)  Thermometer.

2.6.3  Sample Preparation
Sample preparation for coarse-grained  soils  is  similar  to  that
described previously  in Section  2.4.3.   For  fine-grained
soils, samples are compacted  to  the desired  density  using
methods described in  ASTM Method D69a-70.
2.6.4  Test Procedure
1.  Measure and record the height of the specimen, L, and  the
    cross-sectional area of the  specimen, A.
2.  With valve B open (see Figure 3b), crack valve A, and  slowly
    bring the water level up  to  the discharge level  of  the
   • permeameterv
3.  Raise the head of water in the standpipe above the
    discharge level of the permeameter.  The difference in head
    should not result in an excessively  high hydraulic  gradient
    during the test.  Close valves A and B.
4.  Begin the test by opening valve B.   Start the timer.   As
    the water flows through the  specimen, measure and record
    the height of water in the standpipe above  the discharge
    level, hj, at time t±r and the height of water above the
    discharge level,  h£ at time  t2»
5.  Observe and record the temperature of the water  in  the
    permeameter.

2.6.5  Calculations
From the test data, plot the logarithm of head versus  time, on
rectangular coordinate paper or use semi-log paper.  The  slope
of the linear part of the curve is used to determine

-------
                                                            2-12
Iogio(hi/h2)/t.  Calculate the hydraulic conductivity  using
Equation (9).

2.7    MODIFIED COMPACTION PERMEAMETER METHOD
2.7.1  Applicability
This method can be used to determine  the hydraulic conductivity
of a wide range of materials.  The method  is generally used for
remolded fine-grained soils.  The method is generally  used  under
constant-head conditions.  The method was  taken  from Anderson
and Brown, 1981, and EPA  (1980).

2.7.2  Apparatus
The apparatus is shown in Figure 4 and consists  of the equip-
ment and accessories as follows:

   a.   Soil Chamber - A compaction mold having  a diameter
        8 times larger than the diameter of the  largest
        particles.  Typically, ASTM standard mold (Number CN405)
        is used,
   b.   Fluid Chamber - A compaction mold  sleeve having the
        same diameter as the soil chamber,
   c.   2 kg hammer,
   d.   Rubber rings used for sealing purposes,
   e.   A coarse porous stone having higher permeability than
        the tested sample,
   f.   Regulated source of compressed air, and
   g.   Pressure gage or manometer to determine  the pressure
        on the fluid chamber.

2.7.3  Sample Preparation
1.  Obtain sufficient representative soil  sample.  Air dry  the
    sample at room temperature.  Do not oven dry.

-------
                                                            2-13
(2).  Thoroughly mix the selected  representative  sample  with
      water to obtain a desired moisture  content.
(3).  Compact the sample to  the desired density within the
      mold using the method  described  as  part  of  ASTM  Method
      D698-70.
(4).  Level the surface of the compacted  sample with straight
      edge, weigh and determine the density  of the  sample.
(5).  Measure the length and diameter  of  the sample.
(6).  Assemble the apparatus, make sure that there  are no
      leaks, then connect the pressure line  to the  apparatus.
2.7.4  Test Procedure
(1).  Place sufficient volume of water  in  the  fluid  chamber
      above the soil chamber.
(2).  Air pressure must be applied gradually to  flush  water
      through the sample until no air bubbles  in the outflow
      are observed.  For fine-grained soils, the saturation
      may take several hours to several days,  depending  on
      the applied pressure.
(3).  After the sample is saturated, measure and record  the
      quantity of outflow versus time.
(4).  Record the pressure reading (h) on the top of  the  fluid
      chamber when each reading is made.
(5).  Plot the accumulated quantity of outflow versus  time  on
      rectangular coordinate paper.
(6).  Stop taking readings as soon as the  linear portion of
      the curve is defined.
2.7.5  Calculations
The hydraulic conductivity can be calculated  using  Equation  8.

2.8    TRIAXIAL-CELL METHOD WITH BACK PRESSURE
2.8.1  Applicability
This method is applicable for all soil types, but especially
for fine-grained, compacted, cohesive soils in which  full  fluid
saturation of the sample is difficult to achieve.   Normally,
the test is run under constant-head conditions.

-------
                                                                2-14
                         TO REGULATED PRESSURE SOURCE AND

                         PRESSURE GAGE OR MANOMETER USED TO
                         MEASURE H.
                           ~j/\-+—PRESSURE RELEASE VALVE

                                       f^3
                                      mj£^^^^m


                                               TOP PLATE
n^OXVOMX
F J J J ' 1^ .A >
                                               RUBBER "O" RING SEALS
                                              BASEPLATE
                           1	POROUS STONE
                              OUTFLOW TO VOLUMETRIC MEASURING DEVICE.

                              PRESSURE SHOULD BE ATMOSPHERIC OR ZERO
                              GAGE PRESSURE
Figure  4.--Modified compaction  permeameter.
            Note: h in Equation  8 is the difference
            between the regulated inflow pressure
            and the outflow pressure.  Source:
            Anderson and Brown,  1981.

-------
                                                           2-15


2.8.2  Apparatus

The apparatus is similar to conventional  triaxial  apparatus.

The schematic diagram of this apparatus is  shown in  Figure 5.



2.8*3  Sample Preparation

Disturbed or undisturbed samples can be tested.  Undisturbed

samples must be trimmed to the diameter of  the  top cap  and

base of the triaxial cell.  Disturbed samples should be prepared

in the mold using either kneading compaction for fine-grained

soils, or by the pouring and vibrating method for  coarse-grained

soils, as discussed in Section 2.5.3.



2,8.4  Test Procedure


(1).  Measure the dimensions and weight of  the  prepared sample.

(2).  Place one of the prepared specimens on the base.

(3)-  Place a rubber membrane in a membrane stretcher/  turn
      both ends of the membrane over the ends of the stretcher,
      and apply a vacuum to the stretcher.  Carefully lower the
      stretcher and membrane over the specimen  as  shown in
      Figure 9.  Place the specimen cap on  the  top of the
      specimen and release the vacuum on the membrane stretcher.
      Turn the ends of the membrane down around the  base and
      up around the specimen cap and fasten the ends with O-rings,

(4).  Assemble the triaxial chamber and place it in  position in
      the loading device.  Connect the tube from the pressure
      reservoir to the base of the triaxial chamber.  With
      valve C (see Figure 5) on the pressure reservoir  closed
      and valves A and B open, increase the pressure inside the
      reservoir, and allow the pressure fluid to fill the
      triaxial chamber.  Allow a few drops  of the  pressure fluid
      to escape through the vent valve (valve B) to  insure
      complete filling of the chamber with  fluid.  Close valve A
      and the vent valve.

-------
                                                          2-16
Figure 5.-
-Schematic diagram of typical triaxial compression
 apparatus for hydraulic conductivity tests with
 back, pressure.
 Source: U.S. Army Corps of Engineers, 1970

-------
                                                           2-17

(5).   Place saturated filter paper disks having the same
      diameter as that of the specimen between the specimen and
      the base and cap; these disks will also facilitate remo-
      val of the specimen after the test.  The drainage lines
      and the porous inserts should be completely saturated
      with deaired water.  The drainage lines should be as
      short as possible and made of thick-walled, small-bore
      tubing to insure minimum elastic changes in volume due to
      changes in pressure.  Valves in the drainage lines
      (valves E, F, and G in Figure 5) should preferably be of
      a type which will cause no discernible change of internal
      volume when operated.  While mounting the specimen in the
      compression chamber, care should be exercised to avoid
      entrapping any air beneath the membrane or between the
      specimen and the base and cap.

(6).   Specimens should be completely saturated before any
      appreciable consolidation is permitted, for ease and
      uniformity of saturation, as well as to allow volume
      changes during consolidation to be measured with the
      burette; therefore, the difference between the chamber
      pressure and the back pressure should not exceed 5 psi -
      during the saturation phase.  To insure that a specimen
      is not prestressed during the saturation phase, the back
      pressure must be applied in small increments, with ade-
      quate time between increments to permit equalization of
      pore water pressure throughout the specimen.

(7).   With all valves closed, adjust the pressure regulators to
      a chamber pressure of about 7 psi and a back pressure of
      about 2 psi.  Now open valve A to apply the preset
      pressure to the chamber fluid and simultaneously open
      valve F to apply the back pressure through the specimen
      cap.  Immediately open valve G and read and record the
      pore pressure at the specimen base.  When the measured
      pore pressure becomes essentially constant, close valves
      F and G and record the burette reading.

(8).   Using the technique described in step (3), increase the
      chamber pressure and the back pressure in increments,
      maintaining the back pressure at about 5 psi less than
      the chamber pressure.  The size of each increment might
      be 5, 10, or even 20 psi, depending on the compressibi-
      lity of the soil specimen and the magnitude of the
      desired consolidation pressure.  Open valve G and measure
      the pore pressure at the base immediately upon applica-
      tion of each increment of back pressure and observe the
      pore pressure until it becomes essentially constant.  The
      time required for stabilization of the pore pressure may
      range from a few minutes to several hours depending on
      the permeability of the soil.  Continue adding increments
      of chamber pressure and back pressure until, under any
      increment, the pore pressure reading equals the applied
      back pressure immediately upon opening valve G.

-------
                                                           2-18


 (9).    Verify the completeness of saturation by closing valve
        F and increasing the chamber pressure by about 5 psi.
        The specimen shall not be considered completely
        saturated unless the increase in pore pressure imme-
        diately equals the increase in chamber pressure.


(10).    When the specimen is completely saturated, increase the
        chamber pressure with the drainage valves closed to
        attain the desired effective consolidation pressure
        (chamber pressure minus back pressure).  At zero
        elapsed time, open valves E and F.


(11).    Record time, dial indicator reading, and burette
        reading at elapsed times of 0, 15, and 30 sec, 1, 2, 4,
        8, and 15 min, and 1, 2, 4, and 8 hr, etc.  Plot the
        dial indicator readings and burette readings on an
        arithmetic scale versus elapsed time .on a log scale.
        When the consolidation curves indicate that primary
        consolidation is complete, close valves E and F.


(12).    Apply a pressure to burette B greater than that in
        burette A.  The difference between the pressures in
        burettes B and A is equal to the head loss (h); h divided
        by the height of the specimen after consolidation (L)
        is the hydraulic gradient.  The difference between the
        two pressures should be kept as small as practicable,
        consistent with the 'requirement that the rate of flow
        be large enough to make accurate measurements of the
        quantity of flow within a reasonable period of time.
        Because the difference in the two pressures may be very
        small in comparison to the pressures at the ends of the
        specimen, and because the head loss must be maintained
        constant throughout the test, the difference between
        the pressures within the burettes must be measured
        accurately; a differential pressure gage is very useful
        for this purpose.  The difference between the eleva-
        tions of the water within the burettes should also be
        considered (1 in. of water » 0.036 psi of pressure).


(13).    Open valves D and F.  Record the burette readings at
        any zero elapsed time.  Make readings of burettes A and
        B and of temperature at various elapsed times (the
        interval between successive readings depends upon the
        permeability of the soil and the dimensions of the
        specimen).  Plot arithmetically the change in readings
        of both burettes versus time.  Continue making readings
        until the two curves become parallel and straight over
        a sufficient length of time to determine accurately the
        rate of flow as indicated by the slope of the curves.

-------
                                                            2-19

2.8.5  Calculations

The hydraulic conductivity can  be  calculated  using  Equation 8.
2.9    PRESSURE-CHAMBER PERMEAMETER METHOD

2.9.1  Applicability

This method can be used to determine hydraulic  conductivity of

a wide range of soils,  undisturbed and  disturbed  samples  can

be tested under falling-head conditions  using this method.

This method is also applicable  to  both coarse-  and fine-grained

soils, including remolded, fine-grained  materials.


2.9.2  Apparatus

The apparatus, as shown in Figure  6, consists of

       a.  pressure chamber,
       b.  standpipe,
                                     >
       c.  specimen cap and base,  and
       d.  coarse porous plates.

The .apparatus is capable of applying confining  pressure  to

simulate field stress conditions.


2.9..3  Sample Preparation

The sample preparation of disturbed and  undisturbed  conditions

can be prepared in the chamber  and enclosed within the rubber

membrane, as discussed in Section  2.8.4.

-------
                                                 2-20
                                          MIT
        LATMAI.
    MVLACI 0^'kIVILINK
Figure  6.-
-Pressure chamber for hydraulic
 conductivity.
 Sources  U.S. Army Corps  of Engineers,
 1980.

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                                                            2-21


2.9.4  Test Procedure

(1).   By adjusting the leveling bulb, a  confining pressure is
       applied to the sample such  that the  stress conditions
       represent field conditions.   For higher  confining
       pressure, compressed air may  be used.

(2).   Allow the sample to consolidate under  the applied  stress
       until the end of primary consolidation.

(3).   Flush water through the sample until no  indication of
       air bubbles is observed.  For higher head of  water,
       compressed air may be used.

(4).   Adjust the head of water to attain a desired  hydraulic
       gradient.

(5).   Measure and record the head drop in  the  standpipe  along
       with elapsed time until the plot of  logarithm of head
       versus time is linear for more than  three consecutive
       readings.
2.9.5  Calculations

The hydraulic conductivity can be determined  using  Equation  9.
2.10   SOURCES OF ERROR FOR LABORATORY TEST  FOR  HYDRAULIC
       CONDUCTIVITY

There are numerous potential sources of error  in laboratory

tests for hydraulic conductivity.  Table  B summarizes  some

potential errors that can occur.  Olson and  Daniel  (1981) pro-

vide a more detailed explanation of sources  of these errors  and

methods to minimize them.  If  the hydraulic  conductivity does
                                                                i
not fall within the expected range for the soil  type,  as given

in Table C, the measurement should be repeated after checking

the source of error in Table B.

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                                                           2-22
                            TABLE B

         SUMMARY OP PUBLISHED DATA ON POTENTIAL ERRORS
                      IN USING DATA FROM
       LABORATORY PERMEABILITY TESTS ON SATURATED SOILS
     Source of Error and References
     Measured K
Too Low or Too High?
 1.  Voids Formed in Sample Preparation
     (Olson and Daniel, 1981).

 2.  Smear Zone Formed During Trimming
     (Olson and Daniel, 1981).

 3.  Use of Distilled Water as a
     Permeant (Fireman, 1944; and
     Wilkinson, 1969).

 4.  Air in Sample (Johnson, 1954).

 5.  Growth of Micro-organisms
     (Allison, 1947).

 6.  Use of Excessive Hydraulic
     Gradient (Schwartzendruber, 1968;
     and Mitchell and Younger, 1967).

 7.  Use of temperature other than the
     test temperature.

 8.  Ignoring Volume Change Due to
     Stress Change.  (No confining
     pressure used).

 9.  Performing Laboratory Rather
     than In-Situ Tests (Olson and
     Daniel, 1981).

10.  Impedance caused by the test
     apparatus, including the
     resistance of the screen or
     porous stone used to support
     the sample.
        High


        Low



        Low

        Low


        Low



     Low or High


       Varies



       High



     Usually low
       Low

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                                                            2-23
2.11  LEACHATE CONDUCTIVITY USING LABORATORY METHODS

Many primary and secondary leachates  found at disposal  sites

may be nonagueous liquids or aqueous  fluids of high ionic

strength.  These fluids may significantly alter  the intrinsic

permeability of the porous medium.  For example, Anderson  and

Brown (1981) have demonstrated  increases in hydraulic conduc-

tivity of compacted clays of as much  as two orders of magnitude

after the passage of a few pore volumes of a wide range of

organic liquids.  Consequently, the effects of leachate on these

materials should be evaluated by laboratory testing.  The  pre-

ceding laboratory methods can all be  used to determine  leachate

conductivity by using the following guidelines.




2.11.1  Applicability
                                                      i
The determination of leachate conductivity may be required for

both fine-grained and coarse-grained  materials.  Leachates may

either increase or decrease the hydraulic conductivity.

Increases are of concern for compacted clay liners, and

decreases are of concern for drain materials.  The applicability

sections of the preceding methods should be used for selecting

an appropriate test for leachate conductivity.   The use of the

modified compaction method (Section 2.7) for determining leachate

conductivity is discussed extensively in EPA Publication SW870

(EPA 1980).

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                                                               2-24

 2.11.2   Leachate Used

 A supply of  leachate must  be  obtained that  is  as  close in chemi-

 cal  and  physical properties  to the anticipated leachate at the

 disposal site as possible.   Methods for obtaining such leachate

 are  beyond the scope of  this  report.   However, recent publications

 by EPA  (1980, SW-87U;  1982,  SW-846) and Conway and Malloy (1981)

 discuss  methodologies  for  simulating  the leaching environment

 to obtain such leachate.   Procedures  for deairing the leachate

 supply  are given in  Section  2.4.   The importance  of preventing

 bacterial growth in  leachate  tests will depend on the expected

 conditions at the disposal site.   The chemical and physical
i
 properties that may  result in corrosion, dissolution, or

 encrustation of laboratory hydraulic  conductivity apparatus

 should  be determined prior to conducting a  leachate conductivity

 test.   Properties of particular importance  are the pH and the

 vapor pressure of the  leachate.   Both extremely acidic and

 basic leachates may  corrode  materials.   In  general,  apparatus

 for  leachate conductivity  tests should be constructed of inert

 materials, such as acrylic plastic, nylon,  or  teflon.   Metal

 parts that might come  in contact  with the leachate should be

 avoided.  Leachates  with high vapor pressures  may require

 special  treatment.   Closed systems for fluid supply and pressure

 measurement, such as those in the modified  triaxial  cell methods,

 should  be used.


 2.11.3   Safety

 Tests involving  the  use  of leachates  should be conducted under

 a vented hood,  and persons conducting the tests should wear

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                                                            2-25
appropriate protective clothing and eye protection,   standard
laboratory safety procedures such as  those as given by
Manufacturing Chemists Association (1971) should be followed.

2.11.4  Procedures
The determination of leachate conductivity should be  conducted
immediately following the determination of hydraulic  conduc-
tivity (Anderson and Brown, 1981).  This procedure maintains
fluid saturation of the sample, and allows a comparison  of  the
leachate and hydraulic conductivities under the same  test
conditions.  This procedure requires modifications of test
operations as described below.

2.11.5  Apparatus
In addition to a supply reservoir for water as shown  in  Figures
                                  %
3 through 6, a supply reservoir for leachate is required.
Changing the inflow to the test cell  from water to leachate can
be accomplished by providing a three-way valve in the inflow
line that is connected to each of the reservoirs.

2.11.6  Measurements
Measurements of fluid potential and outflow rates are the same
for leachate conductivity and hydraulic conductivity.  If the
leachate does not alter the intrinsic permeability of the
sample, the criteria for the time required to take measurements
is the same for leachate conductivity tests as for hydraulic
conductivity tests.  However, if significant changes  occur  in
the sample by the passage of leachate, measurements should  be

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                                                            2-26
taken until either  the  shape  of  a conductivity versus pore
volume curve can be defined,  or  until the  leachate conductivity
exceeds the applicable  design value  for  hydraulic  conductivity.

2.11.7  Calculations
If the leachate conductivity  approaches  a  constant value.
Equations 8 and 9 can be  used. If the conductivity changes con-
tinuously because of the  action  of the leachate, the  following
modifications should be made.  For constant-head tests,  the
conductivity should be  determined by continuing a  plot of
outflow volume versus time  for the constant  rate part of the
test conducted with water.  For  falling-head tests,  the  slope
of the logarithm of head  versus  time should  be continued.

If the slope of either  curve  continues to  change after the flow
of leachate begins, the leachate is  altering the intrinsic per-
meability of the sample.  The leachate conductivity  in this
case is not a constant.   In this case, values of the  slope of
the outflow curve to use  in Equation 8 or  9  must be  taken  as
the tangent to the  appropriate outflow curve at the  times  of
measurement.

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                                                             3-1
                       3.0  FIELD METHODS



This section discusses methods available for  the determination

of fluid conductivity under field conditions.  As most of  these

tests will use water as the testing  fluid, either natural  for-

mation water or water added to a borehole or  piezometer, the

term hydraulic conductivity will be  used for  the remainder of

this section.  However, if field tests are run with  leachate or

other fluids, the methods are equally applicable.


The location of wells, selection of  screened  intervals, and the
                                                k
appropriate tests that are to be conducted depend upon the spe-

cific site under investigation.  The person responsible for

such selections should be a qualified hydrogeologist or

geotechnical engineer who is experienced in the application of

established principles of contaminant hydrogeology and ground

water hydraulics.  The following are given as general guidelines,


(1).   The bottom of the screened interval should be below the
       lowest expected water level.

(2).   Wells should be screened in the lithologic units that
       have the highest probability  of either receiving
       contaminants or conveying them down gradient.

(3).   Wells up gradient and down gradient of sites  should be
       screened in the same lithologic unit.


Standard reference texts on ground water hydraulics  and con-

taminant hydrogeology that should be consulted include:  Bear

(1972), Bouwer (1978), Freeze and Cherry (1979), Stallman

(1971), and Walton (1970).

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                                                             3-2
The success of  field methods  in  determining  hydraulic conduc-
tivity  is often determined  by the  design,  construction,  and
development of  the well or  borehole  used  for the  tests.
Details of these methods  are  beyond  the scope of  this report;
however, important considerations  are  given  in Sections  3.1
and 3.2.  Detailed discussions of  well installation,  construc-
tion, and development methods are  given by Bouwer (1978),
pages 160-180,  Acker (1974),  and Johnson  (1972).

The methods for field determination  of hydraulic  conductivity
are restricted  to well or piezometer type  tests applicable
below existing  water tables.   Determination  of travel times of
leachate and dissolved solutes above the water table  usually
require the application of  unsaturated flow  theory and methods
which are beyond the scope  of this report.

3.1    WELL-CONSTRUCTION  CONSIDERATIONS
The purpose of  using properly constructed  wells for hydraulic
conductivity testing is to  assure  that test  results reflect
conditions in the materials being  tested,  rather  than the con-
ditions caused  by well construction,   in all cases, diagrams
showing all details of the  actual  well or  borehole constructed
for the test should be made.

3.1.1  Well Installation  Methods
Well installation methods are listed below in order of pre-
ference for ground-water  testing and monitoring.   The order was
determined by the need to minimize side-wall plugging by

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                                                             3-3
drilling fluids and to maximize  the  accurate detection  of
saturated zones.  This order  should  be  used as  a  guide/  com-
bined with the judgment of an experienced  hydrogeologist in
selecting a drilling method.  The  combined uses of wells for
hydraulic conductivity testing,  water-level monitoring,  and
water-quality sampling for organic contaminants were  considered
in arriving at the ranking.

    a.  Hollow-stem auger,
    b.  Cable tool,
    c.  Air rotary,
    d.  Rotary drilling with  non-organic drilling fluids,
    e.  Air foam rotary, and
    f.  Rotary with organic based  drilling fluids.

Although the hollow stem-auger method is usually  preferred for
the installation of most shallow wells  (less than 100 feet),
care must be taken if the tested zone is very fine.   Smearing
of the borehole walls by drilling  action can effectively seal
off the borehole from the adjacent formation.   Scarification
can be used to remedy this.
3.1.2  Wells Requiring Well Screens
Well screens placed opposite  the interval  to be tested  should
be constructed of materials that are compatible with  the fluids
to be encountered.  Generally an inert  plastic  such as  PVC is
preferred for ground-water contamination studies.  The  screen
slot size should be determined to  minimize the  inflow of fine-

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                                                             3-4
grained material  to  the well  during  development and testing.
Bouwer (1978), and Johnson  (1972)  give  a summary of guidelines
for sizing well screens.

The annulus between  the well  screen  and the borehole should be
filled with an artificial gravel pack or sand  filter.
Guidelines for sizing  these materials are given by Johnson
(1972).  For very coarse materials,  it  may be  acceptable to
allow the materials  from the  tested  zone to collapse around
the screen forming a natural  gravel  pack.

The screened interval  should  be  isolated from  overlying and -
underlying zones  by  materials of low hydraulic conductivity.
Generally, a short bentonite  plug  is placed on top of  the
material surrounding the screen, and cement grout is placed in
the borehole to the  next higher  screened interval (in  the case
of multiple screen wells), or to the land surface for  single
screen wells.
Although considerations for sampling may dictate minimum casing
and screen diameters,  the recommended guideline is that wells
to be tested by pumping, bailing,  or injection in coarse-grained
materials should  be  at least  4-inches inside diameter.   Wells
to be used for testing materials of  low hydraulic conductivity
by sudden removal or injection of  a  known volume of fluid should
be constructed with  as small  a casing diameter as possible to
maximize measurement resolution  of fluid level changes.   Casing
sizes of 1.25 to  1.50  inches  usually allow this resolution

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                                                             3-5
while enabling  the efficient  sudden  withdrawal  of water for
these tests.

3.1.3  Wells Not Requiring well  Screens
If the zone to  be tested  is sufficiently indurated that a well
screen and casing is not  required  to prevent caving then, it is
preferable to use a borehole  open  to .the zone to be tested.
These materials generally are thoae  having low to extremely low
hydraulic conductivities.  Consolidated  rocks having high
conductivity because of the presence of  fractures and solution
openings may also be completed without the use  of a screen and
gravel pack.  Uncased wells may  penetrate several zones for
which hydraulic conductivity  tests are to be run.  In these
cases, the zones of interest  can be  isolated by the use of
inflatable packers.

3.2  WELL DEVELOPMENT
For wells that  are constructed with  well screens and gravel
packs, and for  all wells  in which  drilling fluids have been
used that may have penetrated the  materials to  be tested, ade-
quate development of the  well is required to remove these
fluids and to remove the  fine-grained materials from the zone
around the .well screen.   Development is  carried out by methods
such as intermittent pumping, jetting with water, surging, and
bailing.  Adequate development is  required to assure maximum
communication between .fluids  in  the -borehole and the zone to be
tested.  Results from tests run  in wells that ;are inadequately

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                                                             3-6
developed will include an error  caused  by  loss  of  fluid  poten-
tial across the undeveloped  zone,  and computed  hydraulic con-
ductivities will be lower than the actual  value.   Bouwer (1978)
and Johnson (1975) give further  details on well development
including methods to determine when adequate  development has
occurred.

3.3  DATA INTERPRETATION AND TEST  SELECTION CONSIDERATIONS
Hydraulic conductivity may be determined in wells  that are
either cased or uncased as described in Section 3.1.  The tests
all involve disturbing the existing fluid  potential  in the
tested zone by withdrawal from or  injection of  fluid  into a
well either as a slug over an extremely short period  of  time/
or by continuous withdrawal  or injection of fluid.  The
hydraulic conductivity is determined by measuring  the response
of the water level or pressure in  the well as a function of
time since the start; of the  test.   Many excellent  references
are available that give the  derivation  and use  of  the methods
that are outlined below, including Bouwer  (1978),  Walton
(1969), and Lohman (1972).
The selection of a particular test method  and data analysis
technique requires the consideration of the purposes  of  the
test, and the geologic framework in which  the test is to be
run.  Knowledge of the stratigraphic relationships of the zone
to be tested and both overlying  and underlying  materials should
always be used to select appropriate test  design and  data
interpretation methods.

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                                                           3-7
The equations given for all computational methods given here
and in the above references are based on idealized models
comprising layers of materials of different hydraulic conduc-
tivities.  The water-level response caused by disturbing the
system by the addition or removal of water can be similar  for
quite different systems.  For example, the response of a water-
table aquifer and a leaky, confined aquifer to pumping can be
very similar.  Consequently, it is not considered acceptable
practice to obtain data from a hydraulic conductivity test and
interpret the type of hydraulic system present without sup-
porting geologic evidence.
The primary use of hydraulic conductivity data from tests
described subsequently will usually be to aid in siting moni-
toring wells for facility design as well as for compliance with
Subpart F of Part 264.  As such, the methods are abbreviated to
provide guidance in determining hydraulic conductivity only.
Additional analyses that may be possible with some methods to
define the storage properties of the aquifer are not included.
The well test methods are discussed under the following two
categories:  1) methods applicable to coarse-grained materials
and tight to extremely tight materials under confined conditions;
and 2) methods applicable to unconfined materials of moderate
permeability.  The single well tests integrate the effects of
heterogeneity and anisotropy.  The effects of boundaries such
as streams or less permeable materials usually are not detec-
table with these methods because of the small portion of the
geologic unit that is tested.

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                                                             3-8
3.4  SINGLE WELL TESTS
The tests for determining hydraulic  conductivity with  a single
well are discussed below based on methods  for  confined and
unconfined conditions.  The methods  are  usually  called slug
tests because the test  involves  removing a slug  of  water
instantaneously from a  well and  measuring  the  recovery of water
in the well.  The method was  first developed by  Hvorslev (1951),
whose analysis did not  consider  the  effect of  fluid stored  in
the well.  Cooper and others  (1967)  developed  a  method that
considers well bore storage.  However, their method only
applies to wells that are open to the entire zone to be tested
and that tap confined aquifers.  Because of the  rapid  water-
level response in coarse materials,  the  tests  are generally
limited to zones with a transmissivity of  less than about
70 cm2/sec (Lohman, 1972).  The  method has been  extended to
allow testing of extremely tight formations by Bredehoeft and
papadopulos (1980).  Bouwer and  Rice (1976) developed  a method
for analyzing slug tests for  unconfined  aquifers.
3.4.1    Method for Moderately Permeable  Formations  Under
         Confined Conditions
3.4.1.1  Applicability.  This method  is  applicable  for  testing
zones to which the entire zone  is open to  the well  screen or
open borehole.  The method usually  is used in materials of
moderate hydraulic conductivity which allow measurement of
water-level response over a period  of an hour to  a  few  days.

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                                                             3-9
More permeable zones can be  tested with  rapid  response  water-
level recording equipment.   The method assumes that  the tested
zone is uniform in all radial directions from  the  test  well.
Figure 7 illustrates the test geometry for  this method.

3.4.1.2  Procedures.  The slug test  is run  by  utilizing some
method of removing a known volume of water  from the  well bore
in a very short time period  and measuring the  recovery  of the
water level in the well.  The procedures are the same for both
unconfined and confined aquifers.  Water is most effectively
removed by using a bailer that has been  allowed to fill and  -
stand in the well for a sufficiently long period of  time so
that any water-level disturbance caused  by  the insertion of the
bailer will have reached equilibrium.  In permeable  materials/
this recovery time may be as little  as a few minutes.   An
alternate method of effecting a sudden change  in water  level  is
the withdrawal of a weighted float.  The volume of water
displaced can be computed using the  known submersed  volume of
the float and Archimedes' principle  (Lohman, 1972).
Water-level changes are recorded using either  a pressure trans-
ducer and a strip chart recorder, a  weighted steel tape, or an
electric water-level probe.  For testing  permeable  materials
that approach or exceed 70 cm2/sec,  a rapid-response transducer/
recorder system is usually used because  essentially  full reco-
very may occur in a few minutes.  Because the  rate of water-
level response decays with time, water-level or pressure

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                                               3-10
             i,  i
                        WELL CASING
           !   i
*	WELL SCREEN
                   I
                        y/^//^,
                        / CONFINING LAYER////
Figure 7.--Geometry and variable definition for
         slug tests in confined aquifers.

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                                                            3-11
changes should be taken at increments  that  are  approximately
equally spaced in the logarithm of  the time since  fluid
withdrawal.  The test should be continued until the  water  level
in the well has recovered to at least  85 percent of  the  initial
pre-test value.

3.1.1.3  Calculations.  Calculations for determining hydraulic
conductivity for moderately permeable  formations under confined
conditions can be made using the  following:

   a.  Determine the transmissivity of the  tested  zone by
       plotting the ratio h/ho on an arithmetic scale against-
       time since removal of water  (t)  on a logarithmic  scale.
       The observed fluid potential in the  well during the test
       as measured by water level or pressure  is h,  and  h0 is
       the fluid potential before the  instant  of fluid
       withdrawal.  The data plot is superimposed  on type
       curves, such as those given  by  Lohman (1972), Plate 2
       or plotted from Appendix A with the  h/ho and  time axes
       coincident.  The data plot is moved  horizontally  until
       the data fits one of the type curves.   A value of time
       on the data plot corresponding  to a  dimensionless time
       (8) on the type curve plot is chosen, and the transmis-
       sivity is computed from the  following:
                          T * Brc  ,                         (10)
                               t
       where rc is the radius of  the casing  (Lohman,  1972,  p.  29)

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                                                            3-12
       The type curves plotted using data  in Appendix  A are not
       to be confused with those commonly  referred  to  as 'Theis
       Curves' which are used for pumping  tests  in  confined
       aquifers (Lohraan, 1972).  The type  curve  method is a
       general technique of detemining aquifer parameters when
       the solution to the descriptive flow equation involves
       more than one unknown parameter.  Although both the
       storage coefficient and transmissivity of the tested
       interval can be determined with the type  curve  method
       for slug tests, determination of  storage  coefficients is
       beyond the scope of this report.  See Section 3.4.1.4-
       for further discussion of the storage coefficient.

       If the data in Appendix A are used, a type curve for
       each value of a is prepared by plotting F(a,0)  on  the
       arithmetic scale and dimensionless  time  (3)  on  the
       logarithmic scale of semi-log paper.
                                        i
   b.  Determine the hydraulic conductivity by dividing the
       transmissivity by the thickness of  the tested zone.

3.4.1.4  Sources of Error.  The errors that can  arise  in
conducting slug tests can be of three types:  those resulting
from the well or borehole construction, measurement errors,
and data analysis error.
Well construction and development errors.  This  method assumes
that the entire thickness of the zone of interest is open to

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                                                            3-13
the well screen or boreholes and  that  flow  is principally  radial,
If this is not the case, the computed  hydraulic conductivity
may be too high.  If the well  is  not properly developed, the
computed conductivity will be  too low.

Measurement errors can result  from determining or  recording the
fluid level in the borehole and the time of measurement
incorrectly.  Water levels should be measured to an  accuracy  of
at least 1 percent of the initial water-level change.  For
moderately permeable materials, time should be measured with  an
accuracy of fractions of minutes, and  for more permeable
materials, the time should be  measured in terms of seconds or
fractions of seconds.  The latter may  require the  use  of a
rapid-response, pressure transducer and recorder system.

Data analysis errors.  The type curve  procedure requires
matching the data to one of a  family of type curves, described
by the parameter o, which is a measure of the storage  in the
well bore and aquifer.  Papadopulos and others (1973)  show that
an error of two orders of magnitude in the  selection of a  would
result in an error of less than 30 percent  in the  value of
transmissivity determined.  Assuming no error in determining
the thickness of the zone tested, this is equivalent to a  30
percent error in the hydraulic conductivity.

3.4.2    Methods For Extremely Tight Formations Under
         Confined Conditions
3.4.2.1  Applicability.  This  test is  applicable to  materials
that have low to extremely low permeability such as  silts,

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                                                            3-14
clays, shales, and indurated lithologic  units.  The  test  has
been used to determine hydraulic conductivities of shales of  as
low as 10-10 cm/sec.

3.4.2.2  Procedures.  The test described by  Bredehoeft and
papadopulos (1980) and modified by Neuzil  (1982)  is  conducted
by pressurizing suddenly a packed off  zone in  a portion of a
borehole or well.  The test is conducted using a  system such  as
shown in Figure 8.  The system is filled with  water  to a  level
assumed to be equal to the prevailing  water  level.   This  step
is required if sufficiently large times  have not  elapsed  since
the drilling of the well to allow full recovery of water
levels..  A pressure transducer and recorder  are used to monitor
pressure changes in the system for a period  prior to the  test
to obtain pressure trends preceding the  test.  The system is
pressurized by addition of a known volume of water with a
high-pressure pump.  The valve is shut and the pressure decay
is monitored.  Neuzil1s modification uses  two  packers with a
pressure transducer below the bottom packer  to measure the
pressure change in the cavity and one  between  the two packers
to monitor any pressure change caused  by leakage  around the
bottom packer.

3.4.2.3  Calculations.  The modified slug  test as developed by
Bredehoeft and Papadopulos (1980) considered compressive
storage of water in the borehole.  These authors  considered
that the volume of the packed-off borehole did not change

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                                                             3-15
  Prtssure Gage
     Systtm Filled
     with Water
Pump
      Pressure Gage
Land Surface
                              Initial Head
                        	?-in Tested	
                              Interval
                            - Tight  -     	
                            z_ Formatioh^inr:	
                                                    Valve
                     System Filled
                      with Water
                                                           Pump
                                    HHHHHHH P ^pr^r^tH:
                (a)
                 (b)
Figure 8.—Schematic  diagram  for pressurized  slug
            test method in unconsolidated (a)  and
            consolidated (b) materials.   Source:
            Papadopulos and Bredehoeft,  1980.

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                                                            3-16
during the test and that  all  compressive  storage resulted in
compression of water under  the  pressure pulse.   Neuzil (1980)
demonstrated that under some  test  conditions  this is not a
valid assumption.  The computational procedure  is the same in
either case.  Data is plotted in the same manner as for the
conventional slug test and  type curves are used from either
Lohman (1972, Plate 2) or plotted  from data given in Appendix A
as described in Section 3.1.1.3.   The value of  time (t)  and
dimensionless time, (0),  are  determined in the  same manner as
for the conventional tests.   If compression of  water only is
considered, transmissivity  is computed by replacing rc2 by the
quantity (Vw C^P g/»)  in Equation 10:
             B(VW \.v MO/"/-                                (10)
where
       Vw is the volume of water  in  the  packed-off cavity,  1,3;
       Cw is the compressibility  of  water,  LT2M"1,
        p is the density of water ML~3;  and
        g is the accleration of gravity,  LT~2.

If the compressive storage is altered  by changing  the volume of
the packed-off cavity  (V), then the  combined  compressibility of
the water and the expansion of the cavity (Co)  is  used.   GO is
computed by measuring  the volume  of  water injected during

-------
                                                            3-17
pressurization (AV) and the pressure change AP for the
pressurization:
          C0 = —                                          (11)
               VAP

(Neuzil, 1982, page 440).  Use of Co requires  an  accurate  method
of metering the volume of water  injected and the="volume  of the
cavity.
3.4.2.4  Sources of Error.  The  types of errors in this  method
are the same as those for the conventional  slug test.  Errors
may also arise by  inaccurate determination  of  the cavity volume
and volume of water injected.  An additional assumption  that  is
required for this  method is that the hydraulic properties  of
the interval tested remain constant throughout the test.   This
assumption can best be satisfied by limiting the  initial
pressure change to a value only  sufficiently large enough  to
be measured (Bredehoeft and Papadopulos, 1980).

3.4.3    Methods for Moderately  Permeable Materials  under
         Unconfined Conditions
3.4.3.1  Applicability.  This method is applicable to  wells
that fully or partially penetrate the interval of interest
(Figure 9).  The hydraulic conductivity determined will  be
principally the value in the horizontal direction (Bouwer  and
Rice, 1976).
3.4.3.2  Procedures.  A general  method for  testing cased wells
that partly or fully penetrate aquifers that have a  water  table

-------
                                                               3-18
            WELL CASING
                                               IMPENETRABLE STRATUM
                                  KftWtf/xW&y/'

(b) CASED. NO SCREEN, NO
   CAVITY ENLARGEMENT
(a) CASED WITH SCREEN
 Figure  9.—Variable definitions for slug  tests in
             unconfined  materials.  Cased wells are
             open  at the bottom.

-------
                                                            3-19

as the upper boundary of  the  zone  to  be  tested  was  developed  by
Bouwer and Rice  (1976).   The  geometry and  dimensions  that are
required to be known for  the  method are  shown  in  Figure  9.4 , The
test is accomplished by effecting  a sudden change in  fluid
potential in the well by  withdrawal of either  a bailer or sub-
mersed float as discussed in  Section  4.4.1.2.   Water-level
changes can be monitored  with either  a pressure transducer and
recorder, a wetted steel  tape, or  an  electric  water-level
                                                       r
sounder.  For highly permeable formations, a rapid-response
transducer and recorder system is  required.  The  resolution of
the transducer should be  about 0.01 m.

3.4.3.3  Calculations.  The hydraulic conductivity  is calcu-
lated using the  following equation in the  notation  of this
report, taken from Bouwer and Rice (1976)
                 j.n K/r:    .  v
                                                            (12)
Cc  ln R/cw  in Jo
  2 Let          Y
where rc, rw, Le, t, Y, and K  have  been  previously defined or
are defined in Figure 8a.  Yo  is  the value  of  Y  immediately
after withdrawal of the slug of water.   The term R is  an  effec-
tive radius that is computed using  the following equation given
by Bouwer and Rice (1976).
     ln
                In (Lw/rw           (Le/rw)

-------
                                                            3-20
for wells that do not  fully  penetrate  the  aquifer.   If the quan-
tity  (Ho-Lw)/rw) is  larger than  6,  a value of 6 should be used.

For wells that completely penetrate the  aquifer,  the following
equation is used:

      In 5-  . <  —liL.	   + _£— )   ,                   (14)
         rw      In  (Lw/rw)    Wrw

(Bouwer, 1976).  The values  of the  constants A, B,  and C are
given by Figure 10  (Bouwer and Rice, 1976).
For both cases, straight-line portions of  plots of  the
logarithm of Y or YO/Y against time should be used  to determine
the slope, In Yo/Y
           —^*•»  0
              t
Additional methods  for tests under  unconfined conditions are
summarized by Bower  (1976) on pages 117-122.  These methods are
modifications of the cased-well  method described  above that
apply either to an uncased borehole or to  a well  or piezometer
in which the diameter  of the casing and  the borehole are the
same  (Figures 9b and 9c.)
3.4.3.4  Sources of  Error.   The  method assumes that flow of
water from above is  negligible.   If this assumption cannot be
met, the conductivities may  be in error.   Sufficient flow from
the unsaturated zone by drainage would result in  a  high conduc-
tivity value.  Errors  caused by  measuring  water levels and
recording time are similar to those discussed in  Sections
3.4.1.4 and 3.4.2.4.

-------
                                                       3-21
 A
awl
 C
   10
   2
            s   n
90  100
                                                      8
                                                 Jj JO
5OO  1000     5000
       L/f...
         10.  —Carves  defining coefficients  Ar  B,
               and C in  equations 13 and  14  as
               a function of the ratio L/rw.
               Source: Bower and Rice, 1976.

-------
                                                            3-22
3.5    MULTIPLE WELL TESTS
Hydraulic conductivity can also  be determined  by  conventional
pumping tests  in which water  is  continuously withdrawn or
injected using one well,  and  the water-level response  is
measured over  time in or  near more observation wells.   These
methods generally test larger portions  of  aquifers  than the
single well tests discussed in Section  4.4.  For  some  cir-
cumstances these tests may be appropriate  in obtaining data to
use in satisfying requirements of Part  264 Subpart  F.   However,
the large possibility for non-uniqueness in interpretation,
problems involved in pumping  contaminated  fluids, and  the
expense of conducting such tests generally preclude their use
in problems of contaminant hydrogeology.   The  following
references give excellent discussions of the design and
interpretation of these tests:   Lohman  (1972),  Stallman (1971),
and Walton (1970).
3.6  ESTIMATES OF HYDRAULIC CONDUCTIVITY  FOR COARSE-GRAINED
     MATERIALS
To characterize the ground-water  flow  system to  satisfy  the
intent of Part 264 Subpart F, estimates of  the hydraulic con-
ductivity based on grain-size analyses, or visual grain-size
classification may be appropriate.  However,  hydraulic conduc-
tivities determined by these methods are  not to  be  used  in  per-
mit applications.  Several theoretical models are available to
provide these estimates, with one of most widely used being

-------
                                                           3-23
Kozeny-Carmen equation which defines the intrinsic permeability,
as adapted from Bear (1972):
                         ,2
                          -  ,                                (15)
                      180
where n is the effective porosity, and all other terms  are as
previously defined.
An empirical approach that has been used by the U.S. Geological
Survey (Lappala, 1978) in several studies relates conductivity
determined by aquifer testing to grain-size, degree of  sorting,
and silt content.  Table C provides the estimates of hydraulic
conductivity.

-------
                                                                    3-24
                            TABLE C
HYDRAULIC CONDUCTIVITIES ESTIMATED PROM GRAIN-SIZE DESCRIPTIONS
                       (In Peet Per Day)
Grain-Size Class or Range
From Sample Description

Pine-Grained Materials
Clay
Silt, clayey
Silt, slightly sandy
Silt, moderately sandy
Silt, very sandy
Sandy silt
Silty sand
Sands and Gravels
Very fine sand
Very fine to fine sand
Very fine to medium sand
Very fine to coarse sand
Very fine to very coarse sand
Very fine sand to fine gravel
Very fine sand to medium gravel
Very fine sand to coarse gravel
Fine sand
Fine to medium sand
Pine to coarse sand
Pine to very coarse sand
Pine sand to fine gravel
Pine sand to medium gravel
Pine sand to coarse gravel
Medium sand
Medium to coarse sand
Medium to very coarse sand
Medium sand to fine gravel
Medium sand to medium gravel
Medium sand to coarse gravel
Coarse sand
Coarse to very coarse sand
Coarse sand to fine gravel
Coarse sand to medium gravel
Coarse sand to coarse gravel
Very coarse sand
Very coarse sand to fine gravel
Very coarse sand to medium gravel
Very coarse sand to coarse gravel
Pine gravel
Pine to medium gravel
Pine to coarse gravel
Medium gravel
Medium to coarse gravel
Coarse gravel
Degre
Poor










13
27
36
48
59
76
99
128
27
53
57
70
88
114
145
67
74
84
103
131
164
80
94
116
147
184
107
134
1270
207
160
201
245
241
294
334
e of Sorti
Moderate


Lea







20
27
41-47
-
-
—
-
-
40
67
65-72
—
-
-
-
80
94
98-111
-
-
-
107
134
136-156
-
-
147
214
199-227
-
214
334
289-334
231
468
468
ng
Well


s than
1 - 4
5
7-8
9 - 1
11
13

27
-
-
-
—
-
-
-
53

-
-
-
-
-
94
-
-
-
-
-
134
-
-
-
-
187
-
-
-
267
-
-
401
-
602
Sil
Slight


.001



1



23
24
32
40
51
67
80
107
33
48
53
60
74
94
107
64
72
71
84
114
134
94
94
107
114
134
114
120
147
160 .
227
201
234
241
294
334
t Content
Moderate










19
20
27 -
31
40
52
66
86
27
39
43
47
59
75
87
51
57
61
68
82
108
74
75
88
94
100
94
104
123
132
140
167
189
201
243
284

High
I









13
13
21
24
29
38
49
64
20
30
32
35
44
57
72
40
42
49
52
66
82
53
57
68
74
92
74
87
99
104
107
134
144
160
191
234

-------
                                                            3-25
3.7    CONSOLIDATION TESTS
As originally defined by Terzagi  (Terzaghi  and  Peck,  1967)  the
coefficient of consolidation  (Cv) of  a saturated,  compressible,
porous medium is related to the hydraulic conductivity by:

           CV -- — ,                                     (16)
            v
where
           K is the hydraulic conductivity,  LT"1,
           p is the fluid density, ML-3,
           g is the gravitational constant,  LT-2,  and
           a is the soil's compressibility,  LM~lT2.

The compressibility can be determined  in  the laboratory  with
several types of consolidometers, and  is  a  function  of the
applied stress and the previous loading history.   Lambe  (1951)
describes the testing procedure.
The transfer value of results from this testing procedure is
influenced by the extent to which the  laboratory loading simu-
lates field conditions and by the consolidation rate.  The
laboratory loadings will probably be less than the stress that
remolded clay liner will experience; therefore, the  use  of  an
already remolded sample in the consolidometer will probably
produce no measurable results.  This suggests that the test is
of little utility in determining the hydraulic conductivity of
remolded or compacted, fine-grained soils.   Second,  the  con-
solidation rate determines the length  of  the testing period.

-------
                                                            3-26
For granular soils, this rate is fairly rapid.  For  fine-grained
soils, the rate may be sufficiently  slow,  so  that  the  pre-
viously described methods will provide faster results.
Cohesive soils (clays) must be trimmed from undisturbed  samples
to fit the mold, while cohesionless  sands  can be tested  using
disturbed, repacked samples (Freeze  and Cherry, 1979).

In general, EPA believes that consolidation tests  can  provide
useful information for some situations, but prefers  the  pre-
viously described methods because they are direct  measurements
of hydraulic conductivity.  Hydraulic conductivity values
determined using consolidation tests are not  to be used  in  per-
mit applications.
                                                           %
3.8   FRACTURED MEDIA
Determining the hydraulic properties of fractured  media  is
always a difficult process.  Unlike  porous media,  Darcy's Law
is not strictly applicable to flow through fractures,  although
it often can be applied empirically  to large  bodies  of frac-
tured rock that incorporate many fractures.   Describing  local
flow conditions in fractured rock often poses considerable  dif-
ficulty.  Sowers (1981) discusses determinations of  hydraulic
conductivity in rock.  This reference should  be consulted for
guidance in analyzing flow through fractured  media.

Fine-grained sediments, such as glacial tills, are commonly
fractured in both saturated and unsaturated settings.  These
fractures may be sufficiently interconnected  to have a significant

-------
                                                            3-27
influence on ground-water flow, or they may be of very  limited
connection and be of little practical significance.
Frequently, a laboratory test of a small sample of clay will
determine hydraulic conductivity to be on  the order of
10~8 cm/sec.  A piezometer test of the same geologic  unit over
an interval containing fractures may determine a hydraulic  con-
ductivity on the order of perhaps 10~5 or  10"6 cm/sec.  To
assess the extent of fracture interconnection, and hence the
overall hydraulic conductivity of the unit, several procedures
can be used.  Closely spaced piezometers can be installed;  one
can be used as an observation well while water is added to  or
withdrawn from the other.  Alternately, a  tracer might  be added
to one piezometer, and the second could be monitored.   These,
and other techniques are discussed by Sowers (1981).
For situations that may involve flow through fractured  media,
it is important to note in permit applications that an  apparent
hydraulic conductivity determined by tests on wells that inter-
sect a small number of fractures may be several orders  others
of magnitude lower or higher than the value required  to
describe flow through parts of the ground-water system  that
involve different fractures and different  stress conditions
from those used during the test.

-------
                                                            4-1

                         4.0  CONCLUSION

By following laboratory and field methods discussed or
referenced in this report, the user should be able to determine
the fluid conductivity of materials used for liners, caps,
and drains at waste-disposal facilities, as well as materials
composing the local ground-water flow system.  If fluid-
conductivity tests are conducted and interpreted properly/  the
results obtained should provide the level of information
necessary to satisfy applicable requirements under Part 264.

-------
                                                            5-1


                       5.0  REFERENCES
Acker, W. L. , III, Basic procedures  for  soil  sampling  and  core
     drilling, Acker Drill Co., 246  p.,  1974.

Allison, L. E., Soil Science, vol. 63, pp. 439-450,  1947.

American Society for Testing and Materials (ASTM), Annual  Book
     of ASTM Standards, part 19, 1978.

Anderson, D., and K. W. Brown, Organic leachate effects  on the
     permeability of clay liners, in Proceedings  of  Solid  Waste
     Symposium, U.S. EPA, p. 119-lTO", 1981.

Bear, J., Dynamics of fluids in porous media, American Elsevier,
     764 p., 1972.

Bouwer, H., Groundwater hydrology, McGraw Hill, 480  p.,  1978.

Bouwer, H., and R. C. Rice, A slug test  for determining  hydraulic
     conductivity of unconfined aquifers with completely or
     partially penetrating wells, Water  Resources Research,
     12, p. 423-428, 1976.

Bredehoeft, J. D., and S. S. Papadopulos, A method for deter-
      mining the hydraulic properties of tight formations,
      Water Resources Research, 16,  p. 233-238, 1980.

Corrway, R. A., and B. C. Malloy (eds.),  Hazardous Solid  Waste
     Testing:  first conference, ASTM Special Technical
     Publication 760, 1981.

Cooper, k. H., J. D. Bredehoeft, and I.  S. Papadopulos,
     Response of a finite diameter well  to an instantaneous
     charge of water, Water Resources Research, 3, p.  263-269,
     1967.

Fireman, M., Soil Science, vol. 58,  pp.  337-355,  1944.

Freeze, R. A., and J. A. Cherry, Groundwater, Prentice Hall,
     604 p., 1979.

Gordon, B. B., and M. Forrest, Permeability of soil  using  con-
     taminated permeant, in Permeability and Groundwater
     Contaminant Transport, ed. T. F. Zimmie and  C.  0. Riggs,
     ASTM Special Technical Publication  746, p. 101-120, 1981.

Hillel, D., Soil and Water, Academic Press, 288 p.,  1971.

Hvorslev, M. J., Time lag and soil permeability in groundwater
     observations, U.S. Army Corps of Engineers Waterways
     Experiment Station Bull. 36, 1951.

-------
                                                             5-2


Johnson, A. I., Symposium on soil permeability, ASTM STP  163,
     American Society of Testing and Materials, Philadelphia,
     pp. 98-114, 1954.

Johnson, E. E., Inc., Groundwater and wells, Johnson Division,
     UOP, 440 p., 1975.

Lappala, E. G., Quantitative hydrogeology of the Upper
     Republican Natural Resources District, Southwest Nebraska,
     U.S. Geological Survey Water Resources Investigations  78-38,

Larabe, T. W., Soil testing for engineers, John Wiley, N.Y.,
     1951.

Lohman, S. W., Groundwater hydraulics, U.S. Geological Survey
     Professional Paper 708, 70 p., 1972.

Lohraan, S. W., and others, Definitions of selected ground
     water terms - revisions and conceptual refinements,
     U.S. Geological Survey Water Supply Paper 1988, 1972.
     »                                                        —
Manufacturing Chemists Association, Guide for safety in the
     chemical laboratory, Van Nostrand, Reinhold Co., N.Y.,
     1971.

Mitchell, A. K., and J. S. Younger, Permeability and capillarity
     of soils, ASTM STP 417, American Society for Testing and
     Materials, Philadelphia, pp. 106-139, 1967.

Neuzil, C. E., On conducting the modified 'slug1 test in  tight
     formations, Water Resources Research, vol. 18, no. 2,
     pp. 439-441, 1982.

Olsen, R. E., and D. E. Daniel, Measurement of the hydraulic
     conductivity of fine-grained soils, in Permeability  and
     Groundwater Transport, ed. T. F. ZiramTe and C. 0. Riggs,
     ASTM Special Publication 746, p. 18-64, 1981.

Papadopulos, S. S., J. D. Bredehoeft, and H. H. Cooper, Jr., On
     the analysis of "slug test1 data, Water Resources Research,
     9, p. 1087-1089, 1973.

Schwartzendruber, D., Soil Science Society of America Proceed-
     ings, vol. 32, no. 1, pp. 11-18, 1968.

Sowers, G. P., Rock permeability or hydraulic conductivity - an
     overview, in Permeability and Groundwater Transport, ed.
     T. F. ZimmTe and Co. 0. Riggs, ASTM Special Technical
     Publication 746, 1981.

Stallman, R. W., Aquifer-test design, observation and data
     analysis, TWRI, Chap. Bl, Book 3, U.S. Geological Survey,
     U.S. Govt. Printing Office, WAshington, D.C., 1971.

-------
                                                              5-3
Terzaghi, K. , and R. B. Peck, Soil Mechanics in Engineering
     Practice, 2nd Ed., John Wiley & Sons, N.Y., 729 p., 1967.

Walton, W. C., Groundwater resource evaluation, McGraw Hill,  •
     664 p., 1970.

Wilkinson, W. B., In situ investigation in soils and rocks,
     British and Geotechnical Society, Institution of Civil
     Engineers, London, pp.  311-313, 1969.

U.S. Army Corps of Engineers, Laboratory Soil Testing, Water-
     ways Experiment Station Publication EMlllO-2-1906,  1970.

U.S. Environmental Protection Agency, Lining of waste impound-
     ment and disposal facilities, office of Solid Waste Report
     SW-870, 1980.

U.S. Environmental Protection Agency, Hazardous waste guide-
     lines and regulations (proposed), Federal Register,
     Part IV, Dec. 18, 1978.

U.S. Environmental Protection Agency, Test Methods for Evaluating
     Solid Waste, 2nd Edition, SW-846, Superintendent of Documents,
     Government Printing Office, Washington, D.C., 1982.

-------
              6.0 Appendix A

   Values of the function P(o,0) for use in
the conventional and pressurized slug tests.
      Source: Papadopulos et.al. (1973)
                                                    6-1
JW .-I*" --10-' .-10-* .-10- .-10-
0.001
0.002
0.004
0.008
0.008
0.01
0.02
0.04
0.08
0.08
0.1
0.2
0.4
0.6
0.8
1.0
2.0
3.0
4.0
5.0
6.0
7.0
8,0
9.0
10.0
20.0
30.0
40.0
50.0
60.0
80.0
100.0
200.0
0.9994
0.9989
0.9980
0.9972
0.9984
0.9956
0.9919
0.9848
0.9782
0.9718
0.9855
0.9361
0.8828
0.8345
0.7901
0.7489
0.5800
0.4554
0.3613
0.2893
0.2337
0.1903
0.1562
0.1292
0.1078
0.02720
0.01286
0.008337'
0.006209
0.004961
0.003547
0.002763
0.001313
0.9998
0.9992
0.988ft
0.9978
0.9971
0.9965
0.9934
0.9875
0.9819
0.9785
0.9712
0.9459
0.8995
0.8569
0.8173
0.7801
0.6235
0.5033
0.4093
0.3351
0.2759
0.2285
0.1903
0.1594
0.1343
0.03343
0.01448
0.008898
0.006470
0.005111
0.003617
0.002803
0.001322
0.9998
0.9993
0.9987
0.9982 •
0.9976
0.9971
0.9944
0.9894
0.984ft
0.9799
0.9753
0.9532
0.9122
0.8741
0.8381
0.8045
0.6591
0.5442
0.4517
0.3768
0.3157
0.2655
0.2243
0.1902
0.1620
0.04129
0.01667
0.009637
0.00678*
0.005283
0.003691
0.002845
0.001330
0.9997
0.9994
0.9989
0.9984
0.9980
0.9975
0.9952
0.9908
0.9886
0.9824
0.9784
0.9587
0.9220
0.8875
0.8550
0.8240
0.6889
0.5792
0.4891
0.4146
0.3525
0.3007
0.2573
0.2208
0.1900
0.05071
0.01956
0.01062
0.007193
0.005487
0.003773
0.002890
0.001339
0.9997
0.9995
0.9991
0.9988
0.9982
0.9978
0.9958
0.9919
0.9881
0.9844
0.9807
0.9631
0.9298
0.8984
0.8688
0.8401
0.7139
0.6096
0.5222
0.4487
0.3885
0.3337
0.2888
0.2505
0.2178
0.06149
0.02320
0.01190
0.007709
0.005735
0.003883
0.002938
0.001348

-------
           6.0 Appendix A  (continued)
Extended values of F(o,B) for use in slug tests.
    Source: Bredehoeft and Papadopulos (1980)
                                                    6-2
p
C.OoCOOl
C.OOC002
o.oocoo4
O.OQC006
O.OQC008
O.OOC01
o.onco?
o.ooeo4
o.ooco*
o. ope oe
o.ooci
o.onc?
O.OOC4
O.OQC«
o.onca
0.001
O.OOi
0.00*
o.oot
o.ooe
fl.ot
0.02
0.04
0.06
C.OP
0.)
0.2
0.4
0.*
0.8
1.
«.
4.
e.
e.
10.
20.
4C.
*0.
«C.
inc.
?no.
400.
60C.
800.
1000.
a =0.1
0.9993
0.9990
0.9C&6
0.99«2
0.99KO
0.9977
0.9966
0.9955
0.9944
0.9936
•).992fl
0.989H
0.9HSS
0.9P22
•J.9794
0.9769
0.9470
O.S52R
0.9417
0.93?2
0.9236
0.8904
O.»4?l
0.804P
0.7734
0.7459
0.641P
O.S095
0.4227
0.359P
0.3117
0.17ft*
O.OP761
0.05527
0.039*3
0.03065
0.01*06
0.006680
0.004367
0.003?42
O.OP2577
0.001271
C. 000*^07
0.0004143
0.0003140
0.0002510
a =0.2
0.9490
0.94E*
0.99tO
0.947S
0.9971
0.9*46
0.99SS
0.9936
0.9922
0.9909
0.9HS9
0.9857
0.9797
0.9752
0.5713
0.9679
0.9S46
0.93i7
0.9211
0.9069
0.0962
0.65<2
0.7980
0.75*6
0.71SO
0.6665
0.5774
0.44S*
0.364?
0.307?
0.264S
0.1519
0.07496
0.04S9«
o. oatse
0.02670
0.01361
o.oot«;t8
0.00431H
0.003214
0.00?5B9
0.001P66
0.0006296
O.OOC41PP
O.Q003137
o.ooc?«oe
o=OJ&
0.9984
0.9977
0.9968
0.9961
0.9955
0.994S
0.092S
0.9*99
0.9877
0.98SS
0.9»<,i
0.977*
0.9685
0.9615
0.95S7
0.950=
0.9307
0.9031
0.8025
0.86S4
0.850B
O.T947
0.7214
0.6697
0.6289
0.59S1
0.4799
0.3566
0.2«64
0.2397
0.2061
0.1Z02
0.06420
0.04331
0.032S*
0.02600
0.012BR
0.006?74
0.004229
0.003163
0.002526
0.00175R
0.000*272
0.0004177
0.0003131
0.0002S04
a=1
0.9977
0.9968
0.9955
0.9945
0.9936
0.99?9
0.9900
0.9858
0.9827
0.9800
0.9777
0.9687
0.9560
0.9465
O."3ft5
0.9315
0.904B
0.8686
O.«419
0.8202
0.8017
0.7336
0.6489
0.5919
0.5486
0.5137
0.4010
O.?902
0.2311
0.1931
0.1663
0.04912
0.05521
0.03830
0.02933
0.02376
0.01219
0.00*171
0.00413?
0.003105
0.00?487
C. 001247
0.0006242
0.00041A3
0.00031?3
0.0002499
a=2
0.9968
0.9955
0.9936
0.9q?2
0.9910
0.9qOO
0.9AS8
0.9X01
0.9757
0.9720
0.9*86
0.9S62
0.9*89
O.V?56
0.9151
0.9057
0.8702
O.B232
0.7896
0.7626
0.7400
0.6595
0.5*54
0.5055
0.4618
0.4276
0.3234
0.2?92
0.1P17
0.1521
0.1315
O.OB044
0.0466P
0.0^32*
0. 02594
0.02130
0.01133
0.005697
0.003994
0.0030??
0.002431
0.001230
0.0006195
0.0004141
0.0003110
0.0002490
a=5
0.9948
0.9927
0.9B98
0.9876
0.9857
0.9841
0.9776
0.9687
0.9619
0.9562
0.9512
0.9321
0.9061
0.0869
0.8711
0.8576
0.8075
0.7439
0.7001
0.6662
0.6384
0.5450
0.4454
0.3672
0.3469
0.3168
0.2313
0.1612
0.1280
0.1077
0.09375
0.0594Q
0.0362)
0.02663
0.02125
0.0177*
0.009943
0.005395
0.003726
0.002853
0.002313
0.001194
0.0006085
0.0004087
0.0003078
0.0002469
as 10
0.9923
0.9894
0.9853
0.9822
0.9796
0.9773
0.9683
0.9558
0.9464
0.9387
0.9318
0.9059
0.8711
0.8458
0.8253
0.-S079
0.7450
0.6684
0.6178
0.5797
0.5492 "'
0.4517
0.3556
0.3030
0.2682
0.2428
0.1740
0.1207
0.09616
0.08134
0.07120
0.04620
0.02908
0.02185
0.01771
0.01499
0.008716
0.004898
0.003445
0.002666
0.002161
0.001149
0.0005944
0.0004016
0.0003035
0.0002440

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        APPENDIX B
IMMERSION TEST OF MEMBRAiJE




   LINER MATERIALS FOR




COMPATIBILITY WITH WASTES

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                             DRAFT


                          Method 9082


            IMMERSION TEST OF MEMBRANE LINER MATERIALS

                  FOR COMPATIBILITY WITH WASTES




1.0  Scope and Application


     1.1  This test method  is  for use in determining the  effects


          upon the physical properties of flexible rner.brane  liner


          materials intended  to  contain  chemicals  in   a   pit-,


          pond, lagoon  or  landfill-type  installation,   of   the


          chemical environment  expected  to  be encountered.   Data


          from these  tests   will  assist  in  deciding  whether  a


          •given liner  material is  acceptable  for  the' intended


          application.


     1.2  This method is based  on material resulting  frorc  work by


          the National Sanitation Foundation,  Dr.  Henry E. Haxo,


          Dr. Robert Landreth,  Matrecon, Inc. and EPA's Municipal


          Environmental Research  Laboratory  in  Cincinnati,   OH.


2.0  Summary of Method


     2.1  In  order  to  estimate   long   term  compatability,   the


          liner material  is  exposed  to the  expected  chemical
          •

          environment for a period of  120  days  at  an elevated


          temperature.  A comparison' of the  membrane's physical


       —-properties before  and  after   this  contact period is


          used to estimate  the properties  of the  liner  at  the


          time of site closure.


3.0  Interferences


4.0. Apparatus and Materials


     4.1  Exposure tank - A  size sufficient to contain the  samples

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          they do not touch bottom or sides of the tank, or  g*ch

          other; for  stirring the  liquid in  the tank;  and  zor

          holding the specimens  in such  a manner that the lir-jr

          material contacts the test solution only on the surface

          that would  face  the waste  in  an actual disposal site.
                %
          The tank shall be  equipped  with a means of maintaining

          the solution at a temperature of SQ+2*C  and for prevent-

          ing, evaporation  of  the solution  (e.g.,  cover equipped

          with a reflux condenser).   The Agency understands  that

          one such device  is  manufactured by  Associated Design

          and Manufacturing  Company,   814  North  Henry  Street,

          Alexandria, VA 22314, (703)549-5999.

    4.2  Stress-strain machine suitable for measuring elongat:^n,

          tensile strength, tear and puncture resistance.

     4.3  Jig for testing puncture resistance.

     4.4  Labels and holders for specimens, of materials known t be

          resistant to the specific wastes.  Holders of stainless

          steel, and tags  made of  50  mil polypropylene, eir.bossed

          with machinist's numbering dies and  fastened with stain-
                                   «

          less steel wfre,  are resistant to most wastes.

5.0  Reagents

6.0  Sample Collection Preservation and Handling

     6.1  For information  on what  constitutes a representative

          sample of  the waste   fluid  to  employ,  refer to  the

          appropriate guidance document listed below:

          1. RCRA Guidance Document:  Surface  Impoundments,  Liner
             Systems, Final Cover, and  Freeboard  Control.  Is-ued

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             July 1982 and  used 'with 40 CfR  254.221(a)  and (c),
             and 264.228(a).

          2. RCRA  Guidance  Document:  Waste  Pile Design,  Liner
             Systems. Issued  Julv  1932  ar.d  used  with  40  CFR
             264.251(a),  264.252,*and 264.253.

          3. RCRA Guidance Document: Landfill Design, Liner Systems
             and Final Cover.  Issued Ju.'v  1982 and used with 40
             CFR 264.3Cl(a)  and 264.310(af.
7.0 Procedure
     7.1.  Obtain  a representative  sample  of  the waste  fluid.

     7.2  Perform the following tests on uhexposed samples of the

          polymeric membrane liner material:

          7.2.2  Puncture resistance,  thrae specimens

          7.2.3  Tensile strength in two c  • i'ctions, three speci-

                 mens in each direction

          7.2.4  Elongation at  Break,  (Thi ;  test  is  only  to be

                 performed on  membrane  ma.. ="ial  which does  not

                 have a  fabric  or other  n n-elastomeric  support

                 on its reverse [away frcT> w *ste] face.)

          Tests are to  be  performed  according  to  the protocols

          referenced in Table  9082-1.   See  Figure 9C82-1  for  a
                                  t
          suggested cutting pattern.

     7.3  Cut pieces of the lining material,  of a size to fit sample

          holder,  and of  a  sufficient number  to permit at least

          three samples  for  each  test  at  each   test  period.

     7.4  Label the test  specimens with  a plastic  identification

          tag and suspend in sample  of the waste fluid.

     7.5  Expose the  sample to the stirred waste  fluid held at

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     7.6  At the  end of  30,  60,  90  and  120  days  of  exposure,



          remove sufficient  specimen  from  the  waste  fluid   to



          determine the merbrane's physical properties  (see  7.2).



          Place wet  specimen  \n  a  labelled  container  of  fresh



          waste fluid at  room temperature for  at least one hour



          to effect cooling prior to testing.



     7-. 7  Tha sample should 'be tested  within 24 hours  of  removal



          from the bath.  To  test the immersed sample, wipe off any



          waste fluid,   rinse  with  deionized  water, blot specimen



          dry,  and  measure  the physical  properties   listed   in



          7.2.



7.8  Results and Reporti;



     7.8.1  Plot  the  cu-ve   for  each  property   over  the  cirr.e



            period 0 to 1. 0 days.



     7.8.2  Report all ra.  tabulated, and plotted  data.  Evaluation



            of the  resul  
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                            TABLE 9082-1




             PHYSICAL PROPERTY TESTING PROCEDURES




           [Appropriate ASTM  or FTMS(*) Testing Method]
Polymer
?vc
CPE
Butyl rubber
CR
HDPE
EPDM
CO, ECC
CM
PE-SP-A
HDPE -A
L44_/£^ J— I **
CSPE


TN-PVC


T-EPDM


EIA


PVC-CPE
Tensile Strength
& Elongation at Break
D882
D882
D412
D412
D638
D412
D412
. D412
D412
D63b Type IV Dumb ell
at 2 inches/second
D751 Method A


D751 Method A

,
D751 Method A


D751 Method A
'

D882 Method A
Tear
Resistance
D1C04 Die C
D1004 Die C
D624 Die C
Do 2 4 Die C
D1004 Cia C
D624 Die C
D624 Tie C
Co 24 Lie C
D1004 Die C
"""" ' ^ ~ M. ~" * -3

D751 as
modified in
Appendix A
D731 as
modified in
Appendix A
D751 as
modified in
Appendix A
D751 as
modified in
Appendix A
D1104 Die C
Puncture
Resistance
*2065
*2065
*2065
*2065
*2CSS1
*20€5
*2065
• **><"*£ c
*2065
r2C65

*2C65


*2065


*2065


*2065


*2065
Abbreviations:



ASTM:  r ''erican Societv for Testina  and  Materials
  I'. tc; .

-------
PVC(Polyvinyl chloride):   A synthetic  thermoplastic polymer  made
    by polymerizing vinyl chloride.

CPE (Chlorinated polyethylene):   Family of  polymers   produced  by
    chemical reaction of chlorine on polyethylene.   The  resulting
    thermoplastic  elastomers contain 25 to 45% chlorine by weight
    and 0 to 25% crystallinity.

Butyl rubber:  A synthetic rubber based  on  isobutylene and a  smalJ
    amount of isoprene to provide sites for vulcanization.

CR (Polychloroprene):   Generic  name for  a synthetic rubber based
    primarily on on chlorobutadiene.

HDPE (High density polyethylene):   A polymer*   prepared by the low
    pressure polymerization  of  ethylene  as   the  sole  mcnor.er.

EPDM (Ethylene propylene  diane mor.cir.ar):   A synthetic  elastcTer
    based on ethylene,  propylene,  and a small  amount of nonce;, ju-
    gated diene to provide sites for vulcanization.

CO, ECO (Spichlorohydrin  polymers):    Synthetic  rubber  inducing
    two epichlorohydrin 'case
    1.4% sulfur.

TN-PVC (Thermoplastic nitrile-polyvinyl chloride):   An  alloy  o.
    thermoplastic  unvulcanized  nitriie   rubber  and   polyvir  1
    chloride.

T-EPDM (Thermoplastic EPDM):  An ethylene-propylene  diene monc ar
    blend resulting in a thermoplastic  elastomer.

EIA (Ethylene interpolymer alloy):   A blend of   polyethylene  n'd
    polyvinyl  chloride  resulting  in   a thermoplastic  elastomer.

PVC-CPE (Polyvinvl chloride - chloroaulfonated oolvethvlene  all  O*

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                                         icr
U.S.  Ew>'-.•'•-=-	-  •   /en Agency
Region V,
230  Sou: •           •   .  t
Chicago,  liiifiGio

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        ,.    r
   TEAR RESISTANCE.
    TESTjSPECIMENf^

                                                    * .^-JWKUKS*. •;-,• -.nay-.-;.-' «v
                                                     PUNCTURE RESISTANCE
                                                    " ""siIIST_SPECI.MEN "'
Figure  9082-1.   Suggested pattern  for  c tting  test  specimens

-------