PREPARING NO-MIGRATION DEMONSTRATIONS FOR MUNICIPAL SOLID
WASTE DISPOSAL FACILITIES - A SCREENING TOOL
DECEMBER 1998
DISCLAIMER
The information in this document has been funded wholly
or in part by the U.S. Environmental Protection Agency (EPA)
under Contract Number 68-W5-0057. Mention of trade names or
commercial products does not constitute endorsement or
recommendation for use.
NOTICE
The policies set forth in this manual are not final EPA
actions, but are intended solely as guidance. They are not
intended, nor can they be relied upon, to create any rights
enforceable by any party in litigation with the United
States. EPA officials may decide to follow the guidance
provided in this manual, or to act at variance with the
guidance, after analysis of specific site circumstances.
EPA also reserves the right to change this guidance at any
time without public notice.
TABLE OF CONTENTS
1.0 Introduction
2.0 Step 1: Make An Early Determination Of Eligibility
2.1 Recent Changes In Federal Regulations Governing
Small, Dry, Remote MSWLFs
2.2 Determination Of An MSWLF's Eligibility For A
No-migration Exemption
2.2.1 Key Screening Criteria
2.2.2 Analysis Against Key Screening Criteria
for MSWLFs That Have Received Exemptions
2.2.3 Estimation of Time of Travel
2.3 Content Of A NMD
3.0 Step 2: Estimate And Analyze The Cost Of The NMD
3.1 Estimate The Cost Of A NMD
3.2 Analyze The Cost Of The NMD
4.0 Step 3: Follow Cost-effective Methods Of Preparing
The NMD
4.1 Prepare A Clear Written Description Of Needs
4.2 Discuss Needs With Consulting Firms
4.3 Select A Consultant
LIST OF TABLES
2-1 Summary Of Results Of An Informal Analysis of 17
Successful NMPs In Seven States
2-2 Sources Of Site-specific Data On Key Variables Used To
Evaluate No-migration Demonstrations
2-3 Permeability Ranges For Various Types Of Soils
2-4 Matrix For Gross Estimating Of The Velocity Of
Migration Of Hazardous Constituents To The Water Table
2-5 NMD Data Collection Form
3-1 Rates For Costing Various On-site Measurements that May
Be Required By The State (1996)
LIST OF FIGURES
2-1 Decision Tool For Determining The Probability Of A
Successful NMD
APPENDICES
Table
A-1 Criteria Used By States To Make Determinations About
No-migration Exemptions
A-2 Values Found For Key Parameters In Successful
No-migration Demonstrations For Specific MSWLFs In
Arizona, Idaho, Montana, Nevada, New Mexico, Utah, And
Wyoming
A-3 Comparison Of Parameters And Values Used By Each State
1.0 INTRODUCTION
Federal regulations [40 Code of Federal Regulations
(CFR) 258.50(b)] allow owners and operators of municipal
solid waste landfills (MSWLF) to prepare a demonstration
which if successful, results in the exemption of the MSWLF
from groundwater monitoring requirements. The demonstration
is commonly referred to as a no-migration demonstration
(NMD). The applicable federal regulations are as follows.
Groundwater monitoring requirements under 40 CFR
258.51 through 40 CFR 258.55 of this part may be
suspended by the Director of an approved State
for a MSWLF unit if the operator can demonstrate that
there is no potential for migration of hazardous
constituents from that MSWLF unit to the uppermost
aquifer (as defined in 40 CFR 258.2) during the active
life of the unit and the post-closure care period.
This demonstration must be certified by a qualified
groundwater scientist and approved by the director of
an approved State, and must be based upon:
(1) Site-specific field collected measurements,
sampling, and analysis of physical, chemical,
and biological processes affecting
contaminant fate and transport, and
(2) Contaminant fate and transport predictions
that maximize contaminant migration and
consider impacts on human health and the
environment.
States are not required to incorporate these Federal
performance standards into their permitting standards.
Individual states may allow exemptions based on NMDs but
states are not required to consider such demonstrations.
States that do consider NMDs must use criteria that are at
least as stringent as the Federal criteria. Because the
federal regulations are performance standards, they allow
states considerable flexibility in the choice of the
criteria and methods used to evaluate no-migration
demonstrations. This means that decisions about NMDs differ
from state to state, as can requirements governing the amount
of data and level of detail of information required for a
NMD. Many site-specific factors will influence the amount
of information required to support a decision about an NMD,
including predicted time of travel for hazardous
constituents and other conditions.
This guidance is intended to be a screening tool to be
used by owners and operators of MSWLFs to rapidly, but
tentatively, determine their likelihood of preparing a
successful NMD. Such rapid screening is expected to save
significant time and money when the MSWLF clearly does not
meet the applicable performance standards. Alternatively,
the use of this guidance may result in little or no time or
cost savings for those owners and operators whose MSWLFs
fall just short of meeting the performance standards.
This guidance is a screening tool; it does not present
in-depth discussions of technical, site-specific factors
that must be measured and modeled during the latter stages
of preparing an NMD. However, in-depth analysis of site
specific data is a very important process and EPA expects that
no NMDs would be approved without it. Obtaining site-specific
data can be expensive and time-consuming. By using this guide,
owners and operators of MSWLFs can evaluate the likelihood of
success of the NMD and decide if collecting site-specific
data is likely to be worthwhile.
This guidance is not intended to encourage or
discourage owners and operators of MSWLFs from submitting
NMDs to their respective states. It does not provide a
definitive process for issuing a no-migration exemption. A
MSWLF that is a good candidate for a successful NMD
according to this guidance may later be rejected from such
consideration based on more detailed sampling and analysis.
The main goal in preparing this guidance is to present a
profile of information from 17 NMDs filed by owners of
MSWLFs who were successful in securing no-migration
exemptions. The information was obtained from the files of
seven states: Arizona, Idaho, Montana, Nevada, New Mexico,
Utah, and Wyoming. The guidance is based on the
characteristics of these 17 successful NMDs and provides a
practical, step-by-step approach for applying major
screening factors. The States through their permitting programs,
not the U.S. Environmental Protection Agency (EPA), issue the
no migration exemptions. This guidance compares successful
NMDs to the Federal criteria. A favorable rating in this
screening process does not guarantee that an owner or operator
will be able to make a successful NMD.
The audience for this guidance is limited. The
audience is composed primarily of those relatively small
MSWLFs in dry areas (generally west of the Mississippi
River) that do not meet the criteria for a "small and dry"
landfill that are eligible for exemption from the groundwater
monitoring requirements contained in the MSWLF criteria
[40 CFR Section 258.1(f)(1)]. When this guidance was initiated,
the exemption for small MSWLFs in dry areas had been vacated as
a result of a court ruling. The exemption was reinstated on
September 25, 1996.
This guidance contains a three-step process that allows
evaluation of the chances of success and supports decisions
about whether to continue or to abandon the NMD process, as
information is collected. The three steps are presented in
Sections 2.0 through 4.0 of this document, which are
summarized below.
* Section 2.0: Step 1 - Make an Early Determination
of Eligibility: Step 1 is an initial screening
step that has three main parts. First, the recent
reinstatement of the exemption for small, dry,
remote MSWLFs is explained. For MSWLFs that are
not eligible for that exemption, collection of
preliminary data to assess the potential for a
no-migration exemption is discussed. The final
part of Step 1 describes the roles of the state or
tribal authorities in the NMD process and offers
some practical advice about learning about
policies, requirements, and information resources.
* Section 3.0: Step 2 - Estimate the Cost of an NMD:
Step 2 helps build a simple estimate of the cost
of preparing a NMD. The estimate will include
the cost of obtaining regional and site-specific
information necessary for the demonstration process.
The estimate also considers the costs of preparing
the necessary report, including analytical and
report preparation support from a consultant.
* Section 4.0: Step 3 - Collect and Analyze
Information and Data and Write the Demonstration:
Step 3 is a guide to selecting and working with a
consulting firm to plan for the collection and
evaluation of data and to preparing the NMD.
The approach set forth in this guidance should enable
the owner or operator of a MSWLF to pursue the early
decision-making stages of a no-migration demonstration as
efficiently and inexpensively as possible. The approach
relies on early warning signs that can lead to early
abandonment of the effort.
2.0 STEP 1: MAKE AN EARLY DETERMINATION OF ELIGIBILITY
This section has three subsections. Section 2.1
describes the exemption from groundwater monitoring
requirements for small MSWLFs in dry and remote areas.
MSWLFs that qualify for and are located in states that allow
this reinstated exemption need not consider a NMD because they
are already exempt from requirements for groundwater
monitoring. Section 2.2 introduces key hydrogeologic
parameters used in collecting preliminary data to assess the
potential that a MSWLF may be a good candidate for a NMD.
Section 2.3 then discusses the role of state or tribal
authorities in the NMD process. The discussion includes
some practical advice for learning about policies,
requirements, and information resources.
2.1 Recent Changes In Federal Regulations Governing Small,
Dry, Remote MSWLFs
The Land Disposal Program Flexibility Act of 1996
directed EPA to reinstate the groundwater monitoring
exemption for certain small qualifying MSWLFs that had been
vacated by a court decision. Rule changes were promulgated on
September 25, 1996 (61 FR 50410). These regulations, if
implemented by the States, would exempt an estimated 800
qualifying small MSWLFs from groundwater monitoring
for MSWLFs that are "small and dry" or "small and remote."
A "small and dry" MSWLF, by definition, receives an
annual average of 20 or fewer tons of waste per day, is
located in an area that annually receives 25 or fewer inches
of precipitation, and must exhibit no evidence of
contamination of groundwater at the site. All such MSWLFs
are in the western United States.
EPA's definition of a "small and remote" MSWLF is one
that receives an annual average of 20 or fewer tons of waste
per day, serves a community that each year experiences an
interruption of surface transportation of at least three
consecutive months' duration, exhibits no evidence of
contamination of groundwater at the site and must serve a
community that has "no practicable alternative" to
landfilling of its municipal solid waste. Almost all such
facilities are in the state of Alaska.
The exemptions described above, known as the
small-dry-remote exemptions, are valid only under federal
regulations; however, no state is required to allow similar
exemptions. A state can establish additional requirements
for obtaining small-dry-remote exemptions, if that
particular state will grant such exemptions at all. It is
likely, however, that a state will base its decisions about
exemptions on criteria that closely resemble those applied
under federal regulations. Owners and operators of MSWLFs
must work with state authorities to determine whether a
particular facility is eligible for a small-dry-remote
exemption. MSWLFs that are eligible for such exemptions
need not pursue a NMD because they are already exempt from
requirements for groundwater monitoring.
2.2 Determination Of An MSWLF's Eligibility For A
No-migration Exemption
This section first describes key screening criteria
that can be used in determining whether a MSWLF is a
candidate for a no-migration exemption. It then explains
how to compare some key characteristics of a facility with
those of a number of other facilities that have received
exemptions. Such a comparison can help the owner or
operator determine the probability that a NMD will be
successful. The section then describes how to calculate a
conservative estimate of time of travel for hazardous
constituents from the facility to the uppermost aquifer.
2.2.1 Key Screening Criteria
The five variables that significantly influence the
time of travel of leachate from a MSWLF to the uppermost
aquifer are the depth to groundwater, the permeability of
the soil, the precipitation rate, the evapotranspiration
potential, and the net infiltration rate. Therefore, these
variables can be used at a particular MSWLF as key screening
criteria for determining the eligibility of a MSWLF for a
no-migration exemption. These criteria depend almost
entirely on site-specific conditions and their use requires
on-site measurements. In the following paragraphs, each of
the five variables is described.
The depth to groundwater is the distance from the
bottom of the MSWLF to the first layer of saturated soils
that are capable of yielding significant quantities of
water. Some state regulations define this saturated layer
differently, depending on the quality of the groundwater and
the quantity of groundwater yield.
The permeability of the soil refers to the rate at
which water travels through it under saturated flow
conditions. Permeability generally is measured in
centimeters per second (cm/sec), but also can be measured in
feet per year, with one foot per year roughly equivalent to
1 x 10^-6 cm/sec.
The precipitation rate is the amount of rain received
at a MSWLF over a given time period. It usually is
expressed as inches per year, but generally is averaged over
a large number of years to account for annual variability.
The evapotranspiration potential is the maximum amount
of water that could be lost from the soil by the actions of
direct evaporation and transpiration through the leaves of
vegetation in a given area. It is estimated based on such
variables as average annual temperatures and humidities.
The net infiltration rate is the percentage of
precipitation that enters the soils in a given area. The
rate represents the portion of rain water that does not run
off the area and that is not evaporated or transpired.
At MSWLFs in areas that generally have significant
infiltration, leachate will be formed and will move toward
the groundwater. At MSWLFs in areas in which there is
little or no infiltration, there will be little or no
leachate generation, and little or no movement of leachate
toward the groundwater.
2.2.2 Analysis Against Key Screening Criteria for MSWLFs
That Have Received Exemptions
Presented below are the results of an informal analysis
of 17 NMDs filed by owners of MSWLFs who were successful in
securing no-migration exemptions from requirements for
groundwater monitoring at their facilities. Information
about the 17 NMDs analyzed was obtained from the files of
seven states: Arizona, Idaho, Montana, Nevada, New Mexico,
Utah, and Wyoming. In Montana, there were 6 successful
NMDs; in Wyoming, 3; in Idaho, 3; in Utah, 2 and in Arizona,
Nevada, and New Mexico, 1 each.
Table 2-1 summarizes the results of the informal
analysis of successful NMDs (Appendix A provides a summary
of criteria used by states to make determinations about such
demonstrations and site-specific data, as well as a
comparison of parameters and values that were used in the
analysis). Through review of the table, it is possible to
make the following general observations about the
characteristics of the 17 MSWLFs for which NMDs were
analyzed:
* Large MSWLFs (those that receive more than 20 tons
per day) and small MSWLFs (those that receive less
than 20 tons per day) submitted 75 and 25 percent
of the NMDs, respectively (8 MSWLFs submitted data
on waste acceptance rates).
* The values for the criteria set forth in Table 2-1
do not appear to differ significantly between
large and small MSWLFs.
* Annual precipitation is less than 15 inches at
more than 93 percent of the MSWLFs and less than
25 inches at all the MSWLFs. Therefore, all the
MSWLFs meet the definition of "dry" from the
Federal criteria (16 NMDs included data on annual
precipitation).
* Depths to groundwater exceeded 50 feet at more
than 76 percent and 200 feet at more than 53 percent of
the MSWLFs analyzed. (All 17 NMDs included data
on depth to groundwater).
* Maximum soil permeabilities (or hydraulic
conductivities) were equal to or less than 1 foot
per year (1 x 10^-6 centimeter per second
[cm/sec]) at 44 percent of the MSWLFs, and less
than 10 feet per year (1 x 10^-5 cm/sec) at 50
percent of the MSWLFs. However, at 31 percent of
the MSWLFs, maximum permeabilities exceeded 100
feet per year (1 x 10^-4 cm/sec) (16 NMDs included
data on maximum soil permeabilities).
* Annual evapotranspiration rates were equal to or
greater than 30 inches at all MSWLFs analyzed,
exceeding 40 inches at 78 percent of MSWLFs
analyzed (9 NMDs included data on
evapotranspiration).
* Models were included in 57 percent of the NMDs.
The 8 that included models all used the Hydrologic
Evaluation of Landfill Performance (HELP) model.
* At 80 percent of the MSWLFs, the cost of an NMD
was less than $30,000 (cost information was
available for 10 demonstrations).
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TABLE 2-1: SUMMARY OF RESULTS OF AN INFORMAL ANALYSIS OF
17 SUCCESSFUL NMPs IN SEVEN STATES^1
CRITERION SELECTED VALUES FOUND NUMBER LOCATIONS OF
FOR ANALYSIS IN NMDs^2 OF MSWLFs MSWLFs (State)
SIZE OF MSWLF
(Tons per day) <20 2 MT
>20 6 ID, NM, UT, WY
NI^2 9 AZ, ID, MT, NV,
UT
AVERAGE ANNUAL
PRECIPITATION
(Inches) <5 1 NV
6 - 10 7 AZ, ID, MT, NM,
UT, WY
10.1 - 15 7 ID, MT, WY
<25 1 UT^3
NI 1 WY
MINIMUM DEPTH TO
GROUNDWATER (Feet) <50^4 4 AZ, MT, UT
51 - 100 3 MT, WY
101 - 200 1 WY
201 - 300 3 ID, MT
301 - 400 3 ID, MT, UT
>400 3 ID, NM, NV
MAXIMUM SOIL
PERMEABILITY
(Feet/Year) <0.01 1 ID
0.01 - 0.1 2 UT, WY
0.11 - 1.0 4 MT
1.1 - 10.0 1 UT
10.1 - 100^5 3 ID, MT, NM
101 - 1000^6 3 ID, NV, WY
>1000^7 2 AZ, WY
NI 1 MT
HYDROGEOLOGIC
MODELS INCLUDED 8 AZ, ID, NM, NV,
UT
NOT INCLUDED 6 MT
NI 3 WY
AVERAGE ANNUAL
EVAPOTRANSPIRATION
RATE (inches) 30 - 40 2 ID, WY
41 - 60 5 ID, MT, UT
61 - 95 2 AZ, NM
NI 8 MT, NV, WY
NMD COSTS
(x $1,000) <5 2 AZ^8, MT
5 - 10 2 MT, NM
11 - 20 2 UT
21 -30 2 ID, MT
84 1 ID
240 1 ID
NI 7 MT, NV, UT, WY
Notes:
1. The states and number of MSWLFs included in the
analysis are: Arizona (1), Idaho (3), Montana (6),
Nevada (1), New Mexico (1), Utah (2), and Wyoming (3).
2. NI = Not available for one or more MSWLFs
3. Data on precipitation at one MSWLF was reported as a
range of 6 to more than 25 inches; therefore, average
annual precipitation was assumed to be less than 25
inches.
4. The depth to groundwater at the MSWLF in Arizona ranged
from 18 to 160 feet; the range was 6 to 30 feet at a
MSWLF in Montana, and 35 to 80 feet at a MSWLF in Utah.
5. Soil permeabilities ranged from 10 to 100 feet per year
at one MSWLF in Montana and from 0.001 to 100 feet per
year at one MSWLF in Idaho.
6. Soil permeabilities ranged from less than 0.001 to
approximately 150 feet per year at a MSWLF in Idaho,
from less than 0.01 to 1000 feet per year at an MSWLF
in Nevada, and from 2 to approximately 200 feet per
year at an MSWLF in Wyoming.
7. Soil permeabilities ranged from less than 1 foot per
year to approximately 5,200 feet per year at a MSWLF in
Wyoming.
8. The cost of preparation of the demonstration could not be
separated easily from the costs of other activities
that were conducted at the site.
************************************************************
Owners and operators that already have reasonable
estimates of annual precipitation, annual
evapotranspiration, depth to groundwater, and maximum soil
permeabilities for their MSWLFs can use Table 2-1 to make a
reasonable assessment of the probability of obtaining a
no-migration exemption. Figure 2-1 is provided to assist
owners and operators who have such information. It is a
decision tool based on the data presented in Table 2-1. The
four lettered bars in the figure show the various
frequencies at which values for each parameter were found in
successful NMDs. To use the decision tool, follow the
instructions in the footnotes to Figure 2-1. Use the
following example as a further guide for understanding the
instructions for using the figure.
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FIGURE 2-1
[Graphic]
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************************************************************
Example: Suppose a MSWLF receives 7 inches of annual
precipitation annually and experiences 45 inches
of evapotranspiration annually. Suppose further
that the base of the MSWLF is 225 feet above the
uppermost groundwater and that the maximum
permeability of the soil in the area is 3 x 10-5
cm/sec. The owner or operator would begin by
drawing a straight line between the fourth dot
from the top on Bar A to the second dot from the
top on Bar B. Next, the owner or operator would
draw a straight line between the fourth dot from
the top of Bar C and the third dot from the top of
Bar D. Finally, the owner or operator would
connect the center points where the previously
drawn lines intersect Bars F-1 and F-2. The
result would be a fairly good probability that the
MSWLF in this example would prepare a successful
NMD.
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Owners and operators that do not have reasonable
estimates of annual precipitation, annual
evapotranspiration, depth to groundwater, and maximum soil
permeabilities for their MSWLFs can collect such estimates
inexpensively and then apply the decision tool presented in
Figure 2-1. Those owners and operators usually can obtain
such values by contacting the sources of information shown
in Table 2-2.
************************************************************
TABLE 2-2: SOURCES OF SITE-SPECIFIC DATA ON KEY
VARIABLES USED TO EVALUATE NO-MIGRATION
DEMONSTRATIONS
Variable Sources
Depth to groundwater Water resources investigation
reports at U.S. Geological Survey
(USGS) regional libraries
throughout the country. USGS has
published hundreds of detailed
reports of groundwater
investigations. The reports show
well locations.
State and local geologic and
natural resources and soil services
offices and libraries.
Soil permeability Water resources investigation
reports at USGS regional libraries
throughout the country. USGS has
published hundreds of detailed
reports of groundwater
investigations. The reports show
well locations.
State and local geologic and
natural resources and soil service
offices and libraries.
Annual precipitation Publications of the National
Climatic Data Center, of the
National Environmental Satellite
Data and Information Service
(NESDIS), in the National
Oceanographic and Atmospheric
Administration (NOAA), under the
U.S. Department of Commerce (DOC).
State and local meteorological and
agricultural offices and services.
Local airports.
Annual
evapotranspiration Publications of the National
Climatic Data Center, of the
NESDIS, in the NOAA, under the DOC.
State and local meteorological and
agricultural offices and services
Local airports.
Infiltration Publications of the National
Climatic Data Center, of the
NESDIS, in the NOAA, under the DOC.
State and local meteorological and
agricultural offices and services
Local airports.
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In general, information about permeability will be the
most difficult to collect from the sources listed in Table
2-2. Usually, the owner or operator will receive a
description of the type or types of soil that lie between
the ground surface and the uppermost aquifer -- the water
table -- at the MSWLF. Each description should include an
estimate of the thickness of the soil layer being described.
If the sources listed above decline to provide estimates of
permeabilities, but will provide soil descriptions, Table
2-3 can be used to estimate the permeability of each soil
type.
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TABLE 2-3: PERMEABILITY RANGES FOR VARIOUS TYPES OF
SOILS
Permeabilities^3
Centi-
USCS Soil meters
Class per Feet per
(USDA Soil Second Year
Description Class)^2 (cm/sec) (ft/yr)
Sandy GW and GP (GS) >1.0 x >10,000
gravels 10^-2
with very
little
fines
Silty GM 1 x 10^-6 1 to
gravels, to 10^-3 1,000
gravel-
sand-silt
mixtures
Clayey GC 1 x 10^-8 0.01
gravels, to 10^-6 to 1
gravel-
sand-clay
mixtures
Sands and SW and SP >1 x >1,000
gravely (S) 10^-3
sands with
very
little
fines
Silty- SM (FS, LS, 1 x 10^-6 1 to
sands, LFS) to 10^-3 1,000
sand-
silt
mixtures
Clayey SC 1 x 10^-8 0.01 to 1
sands, to 10^-6
sand-clay
mixtures
Inorganic ML (SL, FSL) 1 x 10^-6 1 to 1,000
silts to 10^-3
and very
fine
sands,
rock flour,
silty or
clayey
fine sands,
clayey
silts with
slight
plasticity
Inorganic CL (L, SIL) 1 x 10^-8 0.01
clays of to 10^-4 to 100
low
to medium
plasticity,
gravelly
clays,
sandy clays,
silty clays,
lean clays
Organic OL 1 x 10^-6 1 to
silts and to 10^-4 100
organic
silt-clays
of low
plasticity
Inorganic MH 1 x 10^-6 1 to
silts, to 10^-4 100
micaceous
or
diatomaceous
fine
sandy or
silty
soils,
elastic
silts
Inorganic CH 1 x 10^-8 0.01 to
clays to 10^-6 1
of high
plasticity,
fat clays
Organic OH 1 x 10^-8 0.01 to
clays of to 10^-6 1
medium to
high
plasticity,
organic
silts
Source: Agricultural Handbook Number 456, U.S. Department of
Agriculture (USDA)
Notes:
1. The following definitions apply as used in these
descriptions:
Sand is loose and single-grained. The individual
grains can be seen or felt readily. Squeezed in the
hand when dry, it will fall apart when the pressure is
released. Squeezed when moist, it will form a cast,
but will crumble when touched.
Sandy loam is a soil containing much sand, but which
has enough silt and clay to make it somewhat coherent.
The individual sand grains can be seen and felt
readily. Squeezed when dry, it will form a cast that
will fall apart readily, but if squeezed when moist,
will form a cast that will bear careful handling
without breaking.
Silt loam is a soil having a moderate amount of the
fine grades of sand and only a small amount of clay,
over half of the particles being of the size called
silt. When dry, it may appear cloddy, but the lumps
can be broken readily, and when pulverized, it feels
soft and floury. When wet, the soil readily runs
together and puddles. Either dry or moist, it will
form casts that can be handled freely without breaking,
but will give a broken appearance.
Clay loam is a fine-textured soil that usually breaks
into clods or lumps that are hard when dry. When the
moist soil is pinched between the thumb and finger, it
will form a thin ribbon that will break readily,
barely sustaining its own weight. The moist soil is
plastic and will form a cast that will bear much
handling. When kneaded in the hand, it does not
crumble readily but tends to work into a heavy, compact
mass.
Clay is a fine textured soil that usually forms very
hard lumps or clods when dry and is quite plastic and
usually sticky when wet. When the moist soil is
pinched between the thumb and finger, it will form a
long, flexible ribbon. Some fine clays very high in
colloids are friable and lack plasticity in all
conditions of moisture.
Loam is a soil having a relatively even mixture of
different grades of sand and of silt and clay. It is
mellow, with a somewhat gritty feel, yet fairly smooth
and slightly plastic. Squeezed when dry, it will form
a cast that will bear careful handling, while the cast
formed by squeezing the moist soil can be handled quite
freely without breaking.
2. The Unified Soil Classification System (USCS) is one of
two nationally recognized and widely used systems for
estimating soil properties. The other is the USDA
scale, which also is based on the soil texture and the
various percentages of sand, silt, and clay.
Therefore, the descriptions of a soil's texture can be
used to classify it under either system and to convert
from one system to another.
3. To convert cm/sec to ft/yr multiply by 1,034,645.6.
Thus 1 x 10^-6 cm/sec equals approximately 1 ft/yr.
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Once the permeability and thickness of each layer of
soil beneath the facility have been estimated, the average
permeability can be calculated by multiplying the thickness
of each soil layer by its corresponding permeability, adding
the products, and dividing that sum by the total depth to
the water table.
The decision tool provides a broad screening only. Its
results should not discourage the owner or operator from
continuing to pursue a NMD, unless the site appears to be
at an extreme disadvantage under all criteria. In addition,
the quality of the decision made by applying the decision
tool in Figure 2-1 is related directly to the quality of the
estimates for each of the four parameters. However, it is
not necessary to obtain highly accurate estimates of the
values for the MSWLF at this point in the screening process.
Finally, if it would require too much time or expense to
find values for all the parameters in Figure 2-1, those that
would require unreasonable expenditures can be grossly
estimated for the screening effort.
2.2.3 Estimation of Time of Travel
Another method of quickly and cheaply evaluating the
probability that the NMD for an MSWLF will be successful is
to estimate the time required for hazardous constituents
from the MSWLF to travel to the water table. This method
requires knowledge of the predominant soil type beneath the
MSWLF and an estimate of the net annual infiltration rate
for precipitation at the MSWLF. Both parameters are
available from the sources listed in Table 2-2 (the U.S.
Soil Conservation Service should be particularly helpful in
obtaining the information). When the net infiltration rate
and the predominant soil textures at the MSWLF are known,
Table 2-4 can be used to estimate the minimum depth to
groundwater necessary for a no-migration exemption at an
MSWLF that will operate for 30 years and undergo
post-closure care for an additional 30 years. It should be
noted that the permeability of many clays is well below 17 feet
per year, therefore the use of Table 2-4 will yield conservative
results at many sites where clays are the predominant soil type
(The method used to construct the table is based on equations
taken from the Superfund Site Assessment Manual [EPA 1988]).
************************************************************
TABLE 2-4: MATRIX FOR GROSS ESTIMATING OF THE VELOCITY
OF MIGRATION OF HAZARDOUS CONSTITUENTS TO THE
WATER TABLE^1
Minimum
Depth to
the Water
Table
Average Soil for a
Annual Texture MSWLF
Net Infil- (Permea- With a 60-
tration or ability year Total
Percolation Value Operating Estimated
Rate^2 Used in Life and Velocity of
Calculating and Post- Contaminant
Inches Feet Velocity in Closure Migration
per per in Feet per Care Period (Feet per
Year Year Year)^3 (Feet) Year)^4
1 0.0834 Sand (6,000) 36 0.6
5 0.417 150 2.5
10 0.834 282 4.7
15 1.25 408 6.8
20 1.67 529 8.8
1 0.0834 Sandy 24 0.4
5 0.417 loam (745) 102 1.7
10 0.834 198 3.3
15 1.25 288 4.8
20 1.67 372 6.2
1 0.0834 Silt 18 0.3
5 0.417 loam (196) 80 1.3
10 .834 156 2.6
15 1.25 222 3.7
20 1.67 294 4.9
1 0.0834 Clay 12 0.2
5 0.417 loam (66) 66 1.1
10 0.834 132 2.2
15 1.25 192 3.2
20 1.67 253 4.2
1 0.0834 Clay (17.5) 12 0.2
5 0.417 60 1
10 0.834 114 1.9
15 1.25 174 2.9
20 1.67 228 3.8
NOTES:
1. This table was adapted from instruction for calculating
the velocity of infiltrating rainwater in the Superfund
Exposure Assessment Manual, Office of Emergency and
Remedial Response, EPA (EPA/540/1-88/011). It is
intended for use as a general tool, and should not be
applied to MSWLFs that are located over poorly-sorted
sand, gravel, fractured rock, or karst terrains.
2. You can obtain net infiltration or percolation rates
for your area by contacting the local offices of the
U.S. Soil Conservation Service or your state geological
survey office. The rate is equal to the total annual
average precipitation rate, minus losses of moisture
through runoff and evapotranspiration.
3. Note that these permeabilities are higher than those
measured in many clayey soils; therefore, they
contribute to a conservative estimate of velocities at
sites that have clayey soils.
4. Calculations of velocities of migration of contaminants
were based on the following formula:
V equals q /p
where:
q equals Average percolation or recharge rate (depth
per unit time)
p equals Volumetric moisture content of the
unsaturated zone (decimal fraction
representing volume of water per volume of
soil)
The values used to represent "p" above were specific
for each soil texture shown in the table and originally
were derived through laboratory tests on numerous soils
having those textures, as reported in the Superfund
Exposure Assessment Manual.
************************************************************
When the net infiltration rate is not known, but the
predominant soil texture is known, conservative estimates can
be used to estimate the minimum depth to groundwater
necessary for a no-migration exemption at an MSWLF that
will operate for 30 years and undergo post-closure care for an
additional 30 years. These estimates of minimum depths are
120 feet for sand; 78 feet for sandy loam; 60 feet for silt loan;
48 feet for clay loam; and 24 feet for clay.
The estimates were derived by assuming an annual average
precipitation rate of 25 inches per year, minus values for surface
runoff and evapotranspiration rates taken from Table C-8 in
Hydrologic Simulation on Solid Waste Diposal Sites, Office of
Water and Waste Management, EPA (SW-868), September 1980.
If you know your average annual precipitation rate and you are in
a relatively dry area, you can assume that only 15 percent of the
average annual precipitation will infiltrate. That assumption
represents conservative values of 15 percent runoff and 70 percent
evapotranspiration rates.
2.3 Content Of A NMD
The previous sections of this chapter described how to
apply limited and inexpensively gathered information to
determine whether a NMD can be expected to be successful.
This section suggests the specific types and amounts of
information that state officials will expect to see before
making a decision about a no-migration exemption. Officials
typically responsible for such matters include individuals
having such titles as solid waste engineer, solid waste
management official, or director of a solid waste permit
section. To contact such officials, call the headquarters
of the state department of environmental protection and ask
for the office of solid waste. Make an appointment to visit
with an official of that office. Ask whether the state has
specific guidance for NMDs or any written decision criteria
that can be obtained before the meeting. Explain to the
state official the need to know exactly what types of data
must be submitted. For example, Table 2-5 is a data
collection form for keeping track of the information needed
for the NMD. It is important that the information recorded
be as complete and accurate as possible because that
information will be used to estimate the probable total
costs of preparing the NMD. Be prepared to answer questions
about the MSWLF. In addition, inform the official of the
location and design of the MSWLF and its waste acceptance
rate. Ask which characteristics of the MSWLF would increase
or decrease the probability that it will receive a
no-migration exemption.
************************************************************
TABLE 2-5: NMD DATA COLLECTION FORM
Numbers
Sources and
of Method-
Informa- ologies
tion for
Informa- Not Re-
tion Requiring quired
Required? Measure- On-Site
Types of Data (Y/N/M)^1 ment^2 Testing^3
Depth to
groundwater
Soil permeability
(hydraulic
conductivity)
Soil porosity
Bulk density
of soil
Moisture content
of soil
Moisture content
of waste
Soil moisture at
field capacity
Soil moisture at
the wilting point
Soil classification/
soil texture
Models (list type[s])
Maximum depth of
MSWLF
Average annual
precipitation
Average runoff
rate
Infiltration or
percolation rate
Average annual
evapotranspiration
rate
Thickness of liner
(each material)
Permeability of
liner (each
material)
Thickness of cover
(each layer)
Permeability of
cover
NOTES:
1. Y equals Yes
N equals No
M equals Maybe, because the state appears to be
strongly recommending this type of data
2. Ask the state official about sources of data for those
data requirements that can be satisfied with data from
previous studies of the soils or climate in the area of
the MSWLF. Ask whether there is a maximum distance
from the MSWLF beyond which the state will not allow
the use of data from the literature.
3. Ask the state official about the types of testing that
must be performed directly at the MSWLF. If any such
testing already has been performed, ask the official
whether the results are adequate to meet the state's
requirements without additional testing.
************************************************************
During the meeting with the state official, verify that
all the written guidance and forms necessary to complete the
NMD have been provided. Review each type of data listed in
Table 2-5 and ask whether it is required. If a particular
type of data is required, ask whether the information must
be determined from on-site measurements or whether the
results of similar measurements taken at nearby facilities
are sufficient. As an alternative, ask whether values in
the literature that describe the general hydrogeologic
setting in the area can be used in place of on-site
measurements for certain items. Ask for recommendations of
any specific literature that provide values for particular
data elements. For data that must be collected on a
site-specific basis, ask whether there is a minimum number
of samples that must be collected. In addition, ask whether
there is a minimum number of borings that must be drilled to
collect data on certain parameters and how deep the borings
must be.
Be certain to ask the state official whether there are
any types of data that are not listed in Table 2-5 that must
be included in the NMD. List the additional items in the
blank spaces in the table, and complete all columns of the
table for those items, just as the other items in the table.
Finally, ask the state official which, if any,
hydrogeological models must be run to demonstrate the
migration rates of hazardous materials from the MSWLF. Ask
whether the state will run such models and whether
officials can use default values to make a decision about
the MSWLF without requiring the submittal of a NMD.
Determine whether the state has predesignated certain
portions of the state as good or poor locations for
candidates for no-migration exemptions.
After Table 2-5 has been completed, the next step is to
develop a ballpark estimate of the costs of completing a
NMD for the MSWLF. The next chapter of this manual is a
guide to completing that task.
3.0 STEP 2: ESTIMATE AND ANALYZE THE COST OF THE NMD
This chapter includes two sections. Section 3.1
presents an approach to determining a ballpark estimate of
the costs of preparing an NMD. Section 3.2 presents an
approach to determining whether the preparation of a
demonstration is cost-effective in any particular case.
3.1 Estimate The Cost Of A NMD
Using the data collection form filled out as described
in Section 2.3 (see Table 2-5), identify the information
that already has been collected. For example, much of the
information needed might be found in the permit application
for the MSWLF. Next, identify the information listed on the
data collection form (Table 2-5) that the state will allow
to be obtained from literature. In many cases, an owner or
operator can obtain literature free or for a nominal fee
from local, state, and federal government sources and from
universities. Assume that the cost of obtaining each source
of information is $150.00, except for information that
obviously will require little time to collect. (The figure
of $150.00 is based on the assumption that it would require
approximately four hours of a junior consultant's time, and
$50.00 in other direct costs, to retrieve information from
each literature source.) Some of the information needed for
a particular site may not be available in the literature;
therefore, it may be necessary to revise the cost estimate
after a review of information from the various sources
suggested by the state solid waste official.
After entering the information from literature on the data
collection form, review the types of information
listed on the form that must be collected at the MSWLF
through sampling. Use Table 3-1 to prepare a ballpark
estimate of the cost of each such item. If items required
by the state are not listed in Table 3-1, obtain estimated
unit prices from local soil laboratories, local drillers,
consulting firms, state officials, universities, or owners
or operators of nearby MSWLFs where such testing has been
performed. The estimate will be much more accurate if such
contacts provide information to support the estimates of the
costs of all the items listed in Table 2-5. However, the
rates listed in Table 3-1 can be used to construct a quick
ballpark estimate before making telephone calls to refine
the unit costs upon which the estimate would be based.
************************************************************
TABLE 3-1: RATES FOR COSTING VARIOUS ON-SITE
MEASUREMENTS THAT MAY BE REQUIRED BY THE
STATE (1996)
Number
Unit Re- Total
Types of Data Procedure Cost quired^1 Cost
Depth to Drilled $30/
groundwater boring foot^2
Soil Laboratory $100/
permeability test test
(hydraulic
conductivity)
Soil porosity Laboratory $25/
test test
Bulk density Laboratory $25/
of soil test test
Moisture Laboratory $25/
content test test
of soil
Moisture Laboratory $25/
content of test test
waste
Soil moisture Laboratory $25/
at field test test
capacity
Soil moisture Laboratory $25/
at the test test
wilting
point
Soil classi- Laboratory $25/
fication/soil test test
texture
Models (list Computer $2,000/ 1 $2,000
type[s]) analysis analy-
sis^3
Maximum depth Drilled $20/
of MSWLF boring foot^4
Average NA NA NA NA
annual pre-
cipitation
Average Field $100
runoff measure-
rate ment
Infiltration Field
or percola- measure- $100
tion rate ment
Average NA NA NA NA
annual evapo-
transpiration
rate
Thickness of Drilled $20/
liner (each boring foot^6
material)^5
Permeability Laboratory $100/
of liner analysis test
(each
material)
Thickness of Hand $500
cover (each augering
layer)
Permeability Laboratory $100/
of cover analysis test
TOTAL COSTS NA NA NA
NOTES:
1. The number of measurements needed for each data type
often is expressed in terms of the depths of the
borings to be made. Therefore, it is important to
consider both the total depth and the number of borings
when estimating the total number of each test to be
conducted at your MSWLF
2. This unit cost is based on the assumption that the
boring will be six inches in diameter, will exceed 100
feet in depth, and will be drilled with an air rotary
drill by a three-man crew consisting of one operator
and two unskilled laborers, and that the boring will be
cased, capped, and fitted with a concrete pad. The
diameter of six inches is recommended for borings done
at your site because such borings can be converted into
groundwater monitoring wells if the NMD is not
successful. The added cost of that approach is
approximately $10 per foot.
3. Assumes that data already have been collected and are
available to the modeler. Also assumes 24 hours of a
junior modeler's time and 8 hours of a senior modeler's
time, plus materials.
4. The diameter of the boring is assumed to be two inches.
5. It is not likely that many states will require this
test because it could jeopardize the integrity of the
containment structures of the MSWLF.
6. The diameter of this boring is assumed to be two
inches.
NA equals Not Applicable.
************************************************************
After completing Table 3-1, add the costs and record
the total at the bottom of the right-hand column. Add that
figure to the total cost estimated for collection of the
information that can be obtained from the literature. Add to
the new total $5,000 to retain a consultant to communicate
with the state, analyze information about your site, and
prepare the NMD. In most cases, the consultant should be
able to perform those tasks for less than that amount;
however, a ballpark estimate should err on the high side
rather than the low.
The total cost of groundwater monitoring calculated as
described above should be compared with the estimated cost
of preparing a NMD. In many cases, preparing a NMD costs
far less than groundwater monitoring.
3.2 Analyze The Cost Of The NMD
A method of analysis is to compare the cost of a NMD to
the cost of groundwater monitoring. Once a reasonable
estimate of the costs of the NMD has been prepared, compare
that amount with the cost of installing a groundwater
monitoring system and monitoring the groundwater over the
active life of the MSWLF, plus the post-closure care period.
To estimate the cost of installing a groundwater monitoring
system:
* Multiply $90 by the depth to groundwater at the
site (in feet), and multiply the result by the number of
wells that are likely to be needed. (A state
solid waste official will be able to provide an
estimate of the number of groundwater monitoring
wells that may be needed at a given MSWLF.)
* Add to that number $600 per well per year for 30
years of post-closure care at the MSWLF.
* For monitoring in the first year, add $1,800 per well
* For all annual monitoring conducted after the first year,
add $600 per well for each remaining year of operation
of the MSWLF.
For example, groundwater monitoring at a facility that
has three, 200-foot-deep wells and 20 years of remaining
active life would cost a total of $209,835. In addition, at
least 60 hours of consulting time would be needed for well
design and placement and oversight, estimated at
approximately $5,000, bringing the total costs of
groundwater monitoring for the facility to $214,835. The
cost of an NMD for the same facility could be expected to be
approximately $15,000, assuming that only one boring is
required and that all soil tests would be repeated at
20-foot intervals. That cost should be reduced by the cost
of the boring (approximately $6,000), because the boring can
be used to install a groundwater monitoring well should the
NMD be unsuccessful. Therefore, for a MSWLF that meets the
description above, a NMD can be prepared for an incremental
cost of approximately $9,000, or about four percent of the cost
of installing and operating a groundwater monitoring system.
Such differences between the costs of groundwater monitoring
and those of preparing a NMD are expected to be common to most,
if not all, MSWLFs. In addition, the approach described in the
following chapter allows the owner or operator to recognize
at the earliest possible point that a NMD is likely to be
unsuccessful, so that the effort can be abandoned before
large expenditures of time and effort are made.
4.0 STEP 3: FOLLOW COST-EFFECTIVE METHODS OF PREPARING THE
NMD
The following four steps are the most cost-effective
approach to preparing a NMD:
* Prepare a clear written description of needs and
discuss those needs with state solid waste
officials
* Discuss the needs with consulting firms that
specialize in the field
* Using standard practices, select a consultant
* If state does analysis, no consultant needed
The four steps are discussed in the following subsections.
4.1 Prepare A Clear Written Description Of Needs
This step was completed substantially during the visit
with the state solid waste official. However, it is
important to document all the information that will be
needed for a NMD in a one- or two-page description
supported by a table similar to Table 2-5. Once that
description has been prepared, it may become apparent that
there are some areas of uncertainty concerning the number or
types of tests that must be reported in the NMD. However,
even if there are no information gaps in the description, an
attempt should be made to obtain comments on the information
required in a NMD. In addition, attempt to obtain comments
from those officials on the types of information that will
be crucial to their decision and the types of information
that almost certainly will cause the rejection of an NMD.
Explain that the rationale for asking such questions is to
limit expenditures for consultants to complete the NMD by
terminating the preparation of the NMD at the earliest
indication that it will not succeed. Use the results of the
discussions with state officials to determine whether to
engage a consultant to prepare the NMD. Some states may
have in place formal or informal procedures for analyzing
information about MSWLFs in such a way that only the raw
data on an MSWLF must be presented to them. In those
states, a consultant might not be needed to prepare the
demonstration. However, use of a consultant to oversee the
collection of any field data required by the state is
recommended.
4.2 Discuss Needs With Consulting Firms
Contact three or more consulting firms that specialize
in hydrogeological evaluations. Such firms are listed in
local telephone directories. Recommendations of competent
firms can also be obtained from other owners or operators of
MSWLFs. Call each firm and ask to speak with a senior
hydrogeologist. Explain to that person that you are
considering submittal of a NMD for a MSWLF, and ask to
speak with the appropriate person in the company. Describe
to that person pertinent facts about the MSWLF -- its size,
the depth to groundwater, and the climate -- and explain the
information needs identified in cooperation with state
officials. Agree to provide the firm with an invitation to
bid on the preparation of the NMD, if the firm is
interested. Ask each firm about its experience in preparing
such demonstrations, and encourage the contact to offer an
opinion about the probability that the NMD will be
successful. Ask each contact to comment on whether the
information about data needs identified appear to be
complete and accurate, in light of the firm's experience.
Discuss any major discrepancies related to information needs
with state officials. Ask them to reconfirm the need for
information that one or more consulting firms believed to be
unnecessary, or to reconfirm that there is no need for
information that one or more consulting firms believed to be
crucial.
4.3 Select A Consultant
Prepare an invitation for bid for three or more
consulting firms believed to be reputable, in light of the
recommendations of past clients and the opinion formed
during telephone conversations with their staffs. The
invitation for bid should state clearly exactly what is
expected of the contractor in preparing the NMD. It is
recommended that each contractor be required to provide a
brief summary of the experience of its staff and its company
in preparing such demonstrations, both successful and
unsuccessful. In lieu of such experience, a contractor
should explain how the experiences of its staff and its
company are relevant to the preparation of a successful NMD.
In addition, the bid package should request that each
contractor describe specific criteria that could be used to
trigger the abandonment of the NMD at any of a number of
stages in the preparation process. Such a step-by-step
approach could reduce the cost of preparation of a NMD by
allowing the owner or operator to cease such efforts if
success begins to appear unlikely. For example, a company
may propose to conduct a visual evaluation of coring samples
from borings at the site and make a decision about whether
to proceed with the preparation of the demonstration. Such
interim evaluations could produce significant savings at
sites for which more than one boring or numerous laboratory
tests on soil samples are needed to support a NMD. At the
very least, each firm should be asked to provide a subtotal
of costs for collection and presentation of all required
information, with a preliminary conclusion about the
probability that a NMD would be successful. Such an
approach could save the cost of preparing a demonstration in
cases in which there is very little probability of success.
The instructions in the bid package should state
clearly how the firm awarded the contract will be selected.
For example, the owner or operator may elect to use three
criteria, such as experience, approach, and total cost, in
evaluating the bids. In such a case, each of the bidders
would be rated on a scale of 1 to 10 for its responses to
each of the evaluation criteria. For example, a total cost
that is twice the amount of the lowest offer might receive a
rating of 2 and a bidder that proposes three or more
decision points that collectively have the potential to save
50 percent of the total estimated cost of the project might
receive a rating of at least 8. Next, the score of each
bidder under each criterion would be multiplied by a
weighing factor that represents the relative importance of
that criterion in the evaluation. Finally, the results in
each category would be added to obtain a total score for
each bidder. The bidder having the highest score should be
selected for negotiations to encourage the bidder to reduce
its costs or increase its proposed activities. In all
cases, it is important to maintain control over the
evaluation process, so that no bidder is selected if none
meets the requirements.
APPENDIX
INFORMATION USED TO ANALYZE
NO-MIGRATION DEMONSTRATIONS
IN SEVEN STATES
TABLE OF CONTENTS
A-1 CRITERIA USED BY STATES TO MAKE DETERMINATIONS
ABOUT NO-MIGRATION EXEMPTIONS
A-2 VALUES FOUND FOR KEY PARAMETERS IN SUCCESSFUL NO-MIGRATION
DEMONSTRATIONS MSWLFS IN ARIZONA
A-3 COMPARISON OF PARAMETERS AND VALUES USED BY EACH STATE
************************************************************
TABLE A-1: CRITERIA USED BY STATES TO MAKE
DETERMINATIONS ABOUT NO-MIGRATION EXEMPTIONS
Regulatory Criteria Used to
State Make Determination References
Ari- Exemption from groundwater 40 CFR 258.
zona^1 monitoring requirements 50(b)(1)(2)
* Demonstration that there
is no potential for migration
of hazardous constituents
from that MSWLF to the
uppermost aquifer
--Measurements collected
at specific field sites and
sampling and analysis of
physical, chemical, and
biological processes affecting
the fate and transportation
of contaminants
--Predictions of the fate
and transport of contaminants
that maximize migration of
contaminants and a considera-
tion of the effects on public
health and safety and the
environment
* Certification by a qualified
groundwater scientist
* Approval by the director of
the Department of Environmental
Quality
Idaho Exemption from groundwater Solid Waste
monitoring requirements Facilities
* Demonstration that there Act, Title
is no potential for migration 39, Chapter
of hazardous constituents from 7410
the landfill to the uppermost
aquifer during the active
life of the unit and the
post-closure care period
* Certification by a quali-
fied groundwater scientist
* Approval by the director
of the Idaho Environmental
Council
Montana Exemption from groundwater Solid Waste
monitoring requirements Management,
* Demonstration that there Subchapter 7,
is no potential that hazardous 16.14.714(1)(2)
constituents will contaminate (3)(5)(p. 16-
the uppermost aquifer 793)
* Provision of facility-
specific data and studies
certified by a qualified
groundwater scientist
--Site-specific, field-
collected measurements,
sampling, and analysis of
physical, chemical, and
biological processes
affecting contaminant
fate and transport
--Predictions of contami-
nant fate and transport
that maximize migration
of contaminant and
consider effects on
human health and the
environment
* Demonstration that
groundwater will not become
contaminated for at least
30 years after the facility
is closed
* Installation of vadose
zone monitoring devices,
piezometers, or saturated
zone monitor wells as
required by the department
as part of an ongoing
no-migration demonstration
Nevada Exemption from groundwater Solid Waste
monitoring requirements Disposal,
* Demonstration that there General Pro-
is no potential for migration visions,
of hazardous constituents from 444.7481(a)(b)
that unit to the uppermost (p. 444-116)
aquifer during the active life
of the unit, including the
period of closure and post-
closure care period
--Site-specific measurements
and the sampling and analysis
of physical, chemical, and
biological processes affecting
the fate and transport of
contaminants
--Predictions of the fate
and transport of contaminants
that are based on the maximum
possible rate of migration of
the contaminant and considera-
tion of the effects on public
health and safety and the
environment
* Certification by a qualified
groundwater scientist
* Approval by the solid waste
management authority
New Exemption from part or all of Solid Waste
Mexico groundwater monitoring require- Management
ments under Sections 802 to 806 Regulations,
* Demonstration that there is Part VIII,
no potential for migration of 801.C.1.2
hazardous constituents from (p. 103)
the landfill to the uppermost
aquifer during the active
life and the post-closure
care period
--Site-specific field
measurements and sampling
and analysis of physical,
chemical, and biological
processes affecting fate
and transport of contaminant(s)
--Predictions of the fate
and transport of the contami-
nant(s) that maximize migration
of the contaminant(s) and
consideration of the effects
on public health and welfare
and the environment
* Certification by a qualified
groundwater scientist
* Approval by the secretary
of the Department of the Environment
Utah Exemption from groundwater Solid Waste
monitoring requirements Permitting
* Demonstration that there and Manage-
is no potential for migration ment Rules,
of hazardous substances from R315-308-1
the facility to the ground- (3)(a)(b)
water during the active life (p. 22)
of the facility and the
post-closure care period
--Site-specific, field-
collected measurements and
sampling and analysis of
physical, chemical, and
biological processes affecting
fate and transport of the
contaminant(s)
--Predictions of the fate
and transport of the contami-
nant(s) that maximize migration
of the contaminant(s) and
consideration of the effects
on human health and the
environment
* Certification by a qualified
groundwater scientist
* Approval by the Executive
Secretary of the Department of
Environmental Quality
Exemption from some design R315-302-1
criteria and groundwater (2)(vi)
monitoring requirements (new
or existing facilities that
are seeking expansions)
* Requirement that the MSWLF
be located over an area where
--Groundwater has total
dissolved solids (TDS) of
10,000 milligrams per liter
(mg/L) or higher
--There is extreme depth
to groundwater
--There is a natural
impermeable barrier over
groundwater
--There is no groundwater
Wyoming Exemption from groundwater Solid Waste
monitoring requirements, Rules and
Type I landfill Regulations
* Demonstration that there is Chapter 2,
no potential for migration of Section 6
hazardous constituents from (b)(I)(A)(I),
the facility to the uppermost (P2-32)
aquifer
--Site-specific field
measurements
--Information about the
specific wastes to be disposed
of at the facility
--Predictions of fate and
transport of contaminants,
including use of the hydrologic
evaluation of landfill perfor-
mance model, that maximize
migration of contaminants and
consider effects on human
health and the environment
Type II landfill
* Groundwater monitoring systems
are not automatically required
for Type II landfills, but
may be required after the
department reviews the permit
application
NOTE:
1. Arizona Department of Environmental Quality (ADEQ)
recommends the use of Hydrologic Evaluation of Landfill
Performance (HELP) and MULTIMED models with
site-specific data to satisfy the requirements of 40
CFR 258.50(b)(1)&(2). Arizona does not use the form
displayed in Table 2-5.
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TABLE A-2: VALUES FOUND FOR KEY^1 PARAMETERS IN
SUCCESSFUL NO-MIGRATION DEMONSTRATIONS FOR
SPECIFIC MSWLFS IN ARIZONA
Name of Facility Cerbat
Size (acres) and Disposal 160:NI
Rate (tons/day)
Active Life of Facility (yr) 30-40
Thickness and Permeability 6 in; compacted cover
of Daily Cover material
Depth to Groundwater (ft) 18-160
Average Permeability of Soil Silty and gravelly sand;
or Hydraulic Conductivity 1.23x10^-3 cm/sec*
(sandy/loam)
Annual Precipitation Rate (in) 10
Annual Evapotranspiration 76
Rate (in)
Models Used HELP, vers. 2.05,
WHPA, vers.2.0
(RESSQC)***
Cost To Prepare Petition ($) NI 4,100 to 5,000**
* Typical hydraulic conductivity for a sandy loam was
used for the Hydrologic Evaluation of Landfill
Performance (HELP) program.
** The cost to produce the petition is unclear. Modeling
was being done for various reasons when it was decided
to apply for a no-migration petition. At that point,
substantial information was available to be included in
the petition, thereby keeping the cost to a minimum.
*** Trademark model names.
Name of Facility Clay Peak
Size (acres) and Disposal 120; 44.45
Rate (tons/day)
Active Life of Facility (yr) 68
Thickness and Permeability 6 in; fine-grained soil
of Daily Cover
Depth to Groundwater (ft) 297.9 to 334.9
Average Permeability of Soil 1.4 x 10^-4 to 4.2 x 10^-4
or Hydraulic Conductivity cm/sec; 1.1 x 10^-5 to
4.0 x 10^-18 cm/sec;
1.7 to 3 inches per
foot of soil
Annual Precipitation Rate (in) 10.21
Annual Evapotranspiration 59.85
Rate (in)
Models Used HELP, CHEMFLO, MULTIMED
Cost To Prepare Petition ($) approx. 240K
Name of Facility Lemhi County Landfill
Size (acres) and Disposal 16.5; NI
Rate (tons/day)
Active Life of Facility (yr) >40
Thickness and Permeability 6 in; any soil type
of Daily Cover
Depth to Groundwater (ft) >325
Average Permeability of Soil Clay with high plasticity;
or Hydraulic Conductivity 1.8 x 10^-9 to 3.6 x
10^-9 cm/sec
Annual Precipitation Rate (in) 9.39
Annual Evapotranspiration 30
Rate (in)
Models Used HELP ver. 2.0, CHEMFLO,
SUTRA
Cost To Prepare Petition ($) 84K*
* This number is a factor in the cost of a no-migration
petition. The cost actually incorporates overall
design of the landfill, as well as design of the
collection system.
Name of Facility Pickles Blute
Size (acres) and Disposal 370; NI
Rate (tons/day)
Active Life of Facility (yr) >200
Thickness and Permeability 6 in; fine-grained soil
of Daily Cover
Depth to Groundwater (ft) >400
Average Permeability of Soil NI; 1.0 x 10^-4 to 1.8 x
or Hydraulic Conductivity 10^-9 cm/sec
Annual Precipitation Rate (in) 6-8
Annual Evapotranspiration 50
Rate (in)
Models Used HELP
Cost To Prepare Petition ($) 25K to 30K
Name of Facility Former Laurel Sanitary
Landfill (License No.
203)
Size (acres) and Disposal NI; NI
Rate (tons/day)
Active Life of Facility (yr) NI (closed in 1995)
Thickness and Permeability NI; NI (In accordance with
of Daily Cover Subtitle D Regs.)
Depth to Groundwater (ft) 6-30
Average Permeability of Soil Vertical mitigation rate
or Hydraulic Conductivity of gw; 0.2 - 2.3 ft/yr,
8.11 x 10^-8 cm/sec
Annual Precipitation Rate (in) 14
Annual Evapotranspiration 45
Rate (in)
Models Used Not used
Cost To Prepare Petition ($) 25K
Name of Facility Chester Landfill
Size (acres) and Disposal 48; 1.7
Rate (tons/day)
Active Life of Facility (yr) 70
Thickness and Permeability 6 in to 1 ft; NI
of Daily Cover
Depth to Groundwater (ft) 200 to 250
Average Permeability of Soil NI; NI
or Hydraulic Conductivity
Annual Precipitation Rate (in) 10.64
Annual Evapotranspiration NI
Rate (in)
Models Used Not used
Cost To Prepare Petition ($) NI
Name of Facility Coral Creek Landfill
Size (acres) and Disposal 70; 9
Rate (tons/day)
Active Life of Facility (yr) 28
Thickness and Permeability 6 in; NI
of Daily Cover
Depth to Groundwater (ft) avg. 300
Average Permeability of Soil Tight soils approx.
or Hydraulic Conductivity permeability equals
10^-6 or 10^-7 cm/sec; NI
Annual Precipitation Rate (in) 14
Annual Evapotranspiration NI
Rate (in)
Models Used Not used
Cost To Prepare Petition ($) 5K* plus 2 yrs.
* $5,000 was spent on the engineering portion; however,
two or more unrecorded years of personal time were
expended on the project.
Name of Facility Existing Landfill (Big)
Horn County and City of
Hardin)
Size (acres) and Disposal 76; NI
Rate (tons/day)
Active Life of Facility (yr) NI
Thickness and Permeability 6 in; NI
of Daily Cover
Depth to Groundwater (ft) 60
Average Permeability of Soil 9.5 x 10^-8 cm/sec; NI
or Hydraulic Conductivity
Annual Precipitation Rate (in) 12.3
Annual Evapotranspiration NI
Rate (in)
Models Used Not used
Cost To Prepare Petition ($) 4565.45
Name of Facility Valley County Landfill
Size (acres) and Disposal 40; NI
Rate (tons/day)
Active Life of Facility (yr) 73
Thickness and Permeability 6 in; NI
of Daily Cover
Depth to Groundwater (ft) 50
Average Permeability of Soil 5.1 - 9.6 x 10^-8 cm/sec;
or Hydraulic Conductivity 4.63 x 10^-7 cm/sec
Annual Precipitation Rate (in) 11
Annual Evapotranspiration NI
Rate (in)
Models Used Not used
Cost To Prepare Petition ($) 18K initial study; $9,935-
secondary study & no-mig.
recommended
Name of Facility Beaverhead County
Size (acres) and Disposal <100; NI
Rate (tons/day)
Active Life of Facility (yr) 74
Thickness and Permeability approx 6 in; NI
of Daily Cover
Depth to Groundwater (ft) >350
Average Permeability of Soil 1 x 10^-5 to 1 x 10^-4
or Hydraulic Conductivity cm/sec; 1 x 10^-4 cm/sec
Annual Precipitation Rate (in) 9.53
Annual Evapotranspiration 48
Rate (in)
Models Used Not used
Cost To Prepare Petition ($) 8K to 9K
Name of Facility City of Mesquite Municipal
Waste Landfill
Size (acres) and Disposal 40; NI
Rate (tons/day)
Active Life of Facility (yr) NI
Thickness and Permeability >6 in; compacted cover
of Daily Cover material
Depth to Groundwater (ft) >400
Average Permeability of Soil 1 x 10^-8 cm/sec (silt &
or Hydraulic Conductivity clay) and 1 x 10^-3-
1 x 10^-4 cm/sec (fine
sands); NI
Annual Precipitation Rate (in) 4.1
Annual Evapotranspiration NI
Rate (in)
Models Used HELP II, vers. 2.5
Cost To Prepare Petition ($) NI
Name of Facility Corralitos Landfill
Size (acres) and Disposal 480 (East phase; 200
Rate (tons/day) acres); 350
Active Life of Facility (yr) 20 (East phase)
Thickness and Permeability 6 in; NI
of Daily Cover
Depth to Groundwater (ft) >430
Average Permeability of Soil 1.0 x 10^-4 cm/sec; NI
or Hydraulic Conductivity
Annual Precipitation Rate (in) 9.56
Annual Evapotranspiration 93.95
Rate (in)
Models Used HELP
Cost To Prepare Petition ($) 10K and public hearing
costs
Name of Facility Millard County Landfill
Size (acres) and Disposal 80; 20-25
Rate (tons/day)
Active Life of Facility (yr) 200*
Thickness and Permeability 6 in; compacted cover
of Daily Cover material
Depth to Groundwater (ft) 35-80
Average Permeability of Soil 6 x 10^-9 to 1 x 10^-8
or Hydraulic Conductivity cm/sec; NI
Annual Precipitation Rate (in) 6 to >25
Annual Evapotranspiration 60
Rate (in)
Models Used HELP II, vers. 2.05, WHPA
Cost To Prepare Petition ($) 18K
* The active life of facility is estimated from the
information about the size of the facility (80 acres)
and the size (0.8 acre) and active life (two years) of
each cell.
Name of Facility Long Hollow Sanitary
Landfill
Size (acres) and Disposal NI; NI
Rate (tons/day)
Active Life of Facility (yr) 20+
Thickness and Permeability 6 in; 3 x 10^-3 cm/sec
of Daily Cover
Depth to Groundwater (ft) >300
Average Permeability of Soil 1.9 x 10^-6 cm/sec; NI
or Hydraulic Conductivity
Annual Precipitation Rate (in) <10
Annual Evapotranspiration 50
Rate (in)
Models Used HELP
Cost To Prepare Petition ($) NI
Name of Facility Green River #1 Landfill
Size (acres) and Disposal 40^2; 47.5^3
Rate (tons/day)
Active Life of Facility (yr) 10
Thickness and Permeability 6 in; sandy, rocky loam
of Daily Cover
Depth to Groundwater (ft) >130 (no gw encountered)^4
Average Permeability of Soil 5 x 10^-3 to <1 x 10^-6
or Hydraulic Conductivity cm/sec
Annual Precipitation Rate (in) 4-8
Annual Evapotranspiration 37
Rate (in)
Models Used NI^5
Cost To Prepare Petition ($) NI*
* Exemptions from groundwater monitoring requirements
were granted during permit renewal processes.
Therefore, it appears that it did not cost the landfill
owner a separate amount to apply for a no-migration
demonstration.
Name of Facility Rock Springs Sanitary #1
Landfill
Size (acres) and Disposal 47; 273^6
Rate (tons/day)
Active Life of Facility (yr) 4
Thickness and Permeability 6 in; compacted earth
of Daily Cover
Depth to Groundwater (ft) 52 to >100^7
Average Permeability of Soil 2 x 10^-4 to 2 x 10^-6
or Hydraulic Conductivity cm/sec
Annual Precipitation Rate (in) NI
Annual Evapotranspiration NI
Rate (in)
Models Used NI
Cost To Prepare Petition ($) NI*
* Exemptions from groundwater monitoring requirements
were granted during permit renewal processes.
Therefore, it appears that it did not cost the landfill
owner a separate amount to apply for a no-migration
demonstration.
Name of Facility Sublette County Marbleton
Sanitary #2 Landfill
Size (acres) and Disposal 40; 52^8
Rate (tons/day)
Active Life of Facility (yr) 15
Thickness and Permeability 6 in; NI
of Daily Cover
Depth to Groundwater (ft) 80^8
Average Permeability of Soil 6 x 10^-8 cm/sec
or Hydraulic Conductivity
Annual Precipitation Rate (in) 15
Annual Evapotranspiration NI
Rate (in)
Models Used NI
Cost To Prepare Petition ($) NI*
* Exemptions from groundwater monitoring requirements
were granted during permit renewal processes.
Therefore, it appears that it did not cost the landfill
owner a separate amount to apply for a no-migration
demonstration.
NOTES:
1. The term "key" as used here reflects professional
judgement concerning those items that may have been
most crucial to the state in granting no-migration
exemptions.
2. 40 acres indicate expansion of the landfill after
closure of a 55-acre site.
3. 47.5 tons per day were estimated, from the annual
disposal rate, 12,350 tons per year (260 operating days
per year).
4. Groundwater monitoring is not required, because there
is no groundwater up to a depth of 130 feet.
5. The state permit application review file indicates that
the HELP model was used primarily for the waiver of the
requirement for an engineering containment system.
6. 273 tons per day were estimated from the estimated
monthly disposal rate, 6,550 cubic yards per month,
assuming 24 days (Monday through Saturday working days
at the landfill) per month.
7. According to site-specific geology and poor water
quality data, groundwater monitoring is not required.
However, as an alternative, lysimeters have been
installed at this site to measure fluid content of the
substrata.
8. The daily disposal rate was calculated from the annual
disposal rate of 19,000 tons per year, assuming seven
working days per week.
9. No groundwater was detected during the drilling
operation. The depth to groundwater, 80 feet, was
obtained from information about domestic wells from the
state engineer's office.
NI Information not included
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TABLE A-3: COMPARISON OF PARAMETERS AND VALUES USED BY
EACH STATE -- KEY^1 PARAMETERS AND RANGE
VALUES
Name of Facility Arizona*
Size (acres) and Disposal 160;NI
Rate (tons/day)
Active Life of Facility (yr) 30-40
Thickness and Permeability 6 in; compacted cover
of Daily Cover material
Depth to Groundwater (ft) 18-160 (>120)
Average Permeability of Soil Silty and gravelly sand;
or Hydraulic Conductivity 1.23 x 10^-3 cm/sec*
(sandy loam)
Annual Precipitation Rate (in) 10
Annual Evapotranspiration 76
Rate (in)
Models Used HELP, vers. 2.05, WHPA,
vers. 2.0(RESSQC)
Cost To Prepare Petition ($) NI, 4.1K to 5K
* Only one facility within the state has been approved
for a no-migration petition at this time.
Name of Facility Idaho
Size (acres) and Disposal 16.5 to 370; 44.45
Rate (tons/day)
Active Life of Facility (yr) >40 to >200
Thickness and Permeability 6 in; any soil type and
of Daily Cover fine grained soil
Depth to Groundwater (ft) 297.9 to >400
Average Permeability of Soil 1.4 x 10^-4 to 4.2 x 10^-4
or Hydraulic Conductivity cm/sec and clay w/high
plasticity; 1.0 x 10^-4
to 4.0 x 10^-18 cm/sec
Annual Precipitation Rate (in) 6-10.21
Annual Evapotranspiration 30 to 59.85
Rate (in)
Models Used HELP, CHEMFLO, MULTIMED
SUTRA
Cost To Prepare Petition ($) 25K to 240K
Name of Facility Montana
Size (acres) and Disposal 40 to <100; 1.7 to 9
Rate (tons/day)
Active Life of Facility (yr) 28 to 74
Thickness and Permeability 60 to 12 in; NI
of Daily Cover
Depth to Groundwater (ft) 6 to >350
Average Permeability of Soil 1 x 10^-4 to 9.6 x 10^-8
or Hydraulic Conductivity cm/sec (vertical
migration of gw; 0.2-
2.3 ft/yr); 1 x 10^-4
to 8.11 x 10^-8 cm/sec
Annual Precipitation Rate (in) 9.53 to 14
Annual Evapotranspiration 45 to 48
Rate (in)
Models Used Not used
Cost To Prepare Petition ($) 5 to 25K
Name of Facility Nevada*
Size (acres) and Disposal 40; NI
Rate (tons/day)
Active Life of Facility (yr) NI
Thickness and Permeability >6 in; compacted cover
of Daily Cover material
Depth to Groundwater (ft) >400
Average Permeability of Soil 1 x 10^-8 cm/sec (silt &
or Hydraulic Conductivity clay) and 1 x 10^-3 -
1 x 10^-4 cm/sec (fine
sands); NI
Annual Precipitation Rate (in) 4.1
Annual Evapotranspiration NI
Rate (in)
Models Used HELP II, vers. 2.5
Cost To Prepare Petition ($) NI
* Only one facility within the state has been approved
for a no-migration petition at this time.
Name of Facility New Mexico*
Size (acres) and Disposal 480 (East phase; 200
Rate (tons/day) acres); 350
Active Life of Facility (yr) 20 (East phase)
Thickness and Permeability 6 in; NI
of Daily Cover
Depth to Groundwater (ft) >430
Average Permeability of Soil 1.0 x 10^-4 cm/sec; NI
or Hydraulic Conductivity
Annual Precipitation Rate (in) 9.56
Annual Evapotranspiration 93.95
Rate (in)
Models Used HELP
Cost To Prepare Petition ($) 10K and public hearing
costs
* Only one facility within the state has been approved
for a no-migration petition at this time.
Name of Facility Utah
Size (acres) and Disposal 80; 20 to 25
Rate (tons/day)
Active Life of Facility (yr) 20 plus to 200
Thickness and Permeability 6 in; compacted cover
of Daily Cover material and 3 x 10^-3
cm/sec
Depth to Groundwater (ft) 35 to >300
Average Permeability of Soil 1.9 x 10^-6 to 6 x 10^-9
or Hydraulic Conductivity cm/sec; NI
Annual Precipitation Rate (in) 6 to >25
Annual Evapotranspiration 60
Rate (in)
Models Used HELP, WHPA
Cost To Prepare Petition ($) 18K
Name of Facility Wyoming
Size (acres) and Disposal 40 to 47; 47.5 to 273
Rate (tons/day)
Active Life of Facility (yr) 4 to 15
Thickness and Permeability 6 in; sandy, rocky loam
of Daily Cover and compacted earth
Depth to Groundwater (ft) 52 to >130
Average Permeability of Soil 5 x 10^-3 to 6 x 10^-8
or Hydraulic Conductivity cm/sec
Annual Precipitation Rate (in) 4 to 15
Annual Evapotranspiration 37
Rate (in)
Models Used HELP
Cost To Prepare Petition ($) NI
NOTE:
1. The term "key" as used here reflects professional
judgement concerning those items that may have been
most crucial to the state in granting no-migration
exemptions.
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