United States
Environmental Protection
Agency
Environmental Monitoring Systems
Laboratory
Las Vegas NV 89114
Research and Development
EPA-600/S4-83-050 Dec. 1983
Project Summary
A Methodology to Inventory,
Classify, and Prioritize
Uncontrolled Waste Disposal Sites
Ann B. Nelson, Louise A. Hartshorn, and Richard A. Young
A comprehensive approach has been
developed for use by local governments
to inventory active and inactive waste
disposal sites for which little or no
information is available and to establish
priorities for further investigation. This
approach integrates all available histor-
ic, engineering, geologic, land use,
water supply, and public agency or
private company records to develop as
complete a site profile as possible.
Historic aerial photographs provide the
accuracy and documentation required
to compile a precise record of site
boundaries, points of access, and adja-
cent land use. Engineering borings for
construction projects in the vicinity of
suspected sites can be integrated with
geologic information to construct rea-
sonable hydrogeologic models to evalu-
ate potential leachate impact on water
wells or nearby inhabitants. Sites are
systematically ranked in terms of poten-
tial hazard, based on current land use,
hydrogeology, and proximity to water
wells. Greatest attention is given to
those sites that could impact public or
private drinking water supplies.
This kind of evaluation is a necessary
step in prioritizing abandoned dump
sites where little is known about con-
tents and where numbers of sites pre-
clude a comprehensive drilling or testing
program. Case histories from Monroe
County, New York, indicate that a well-
designed study provides a conservative
estimate of the number of large dump
sites which deserve further considera-
tion. The Monroe County study also
provided a comprehensive, 50-year
inventory of all potentially significant
sites in a large urban area (Rochester,
NY) in which at least 90 percent of
initially identified targets were either
eliminated or were not classified as high
priority sites.
This report was submitted in fulfill-
ment of Contract No. 14043 under the
sponsorship of the U.S. Environmental
Protection Agency. This report covers a
period from July 1981 to July 1982,
and work was completed as of Novem-
ber 1,1982.
This Project Summary was developed
by EPA's Environmental Monitoring
Systems Laboratory, Las Vegas, NV, to
announce key findings of the research
project that is fully documented in a
separate report of the same title (see
Project Report ordering information at
back).
Introduction
In order to locate and classify uncon-
trolled waste disposal sites that could
pose a hazard to human health, accurate
information is needed on site locations,
boundaries, contents, subsurface hydro-
geologic conditions, and proximal land
uses. Documentation of past waste dis-
posal activities is at best incomplete and,
in many instances, nonexistent. An accu-
rate and inexpensive method is needed to
develop site information based on existing
data so that expensive drilling and testing
programs can be focused on those sites of
greatest potential hazard to human
health.
This report describes a comprehensive
approach that can be used by local
governments, particularly counties and
large municipalities, to inventory active
and inactive waste disposal sites for
which little or no information is available
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and to establish priorities for further
investigation. The methods were devel-
oped in Monroe County, New York, in
response to county and state require-
ments to locate suspected inactive hazard-
ous waste sites.
The Monroe County approach provides
a method for inventorying both known
and unknown sites at the countywide
level. The method, described schemat-
ically in Figure 1, involves accurately
delineating site locations and boundaries,
developing site profiles, and using geo-
logic information to rank sites in terms of
their potential impact on drinking water
supplies and nearby populations. This is
accomplished by integrating data from a
variety of sources. Table 1 lists some of
the available sources.
A number of comprehensive systems
have been proposed to rank the hazard
potential of waste disposal sites. These
detailed ranking systems cannot be ap-
plied to the type of information developed
from this more general survey of sites
because they require considerable site-
specific information. The methodology
developed for this study was designed to
inventory and rank active and inactive
sites for which little information is avail-
able. The ranking scheme is an attempt to
apply a relative hydrogeologic ranking
scale to all dump sites within a specific
area, such as a county, so that significant
sites can be further investigated in a
logical, consistent, scientific, and efficient
manner.
Historical aerial photographs provide
the accuracy and documentation required
to compile a precise record of site bound-
aries, points of access, and adjacent land
use. Interviews and files in various gov-
ernment agencies substantiate types of
activity noted on the photos and provide
information on water supply locations.
Data from engineering borings for con-
struction projects in the vicinity of sus-
pected sites are integrated with geologic
information to construct preliminary hy-
drogeologic models to evaluate potential
leachate impact on water supplies or
nearby inhabitants.
When all the information has been
collected and reviewed, the sites are
identified as one of five types, and if
sufficient information is available, as-
signed ranks for current land use, hydro-
geology, and proximity to water supplies.
Construction of matrices using combina-
tions of these rankings for individual sites
allows the development of an overall site
ranking. Depending on the variables that
might be considered most important in
each region, the relative ranking derived
Search Records
and
Aerial Photos
Analyze
Regional
Hydrogeology
Determine
Land Use
Analyze
Site-Specific
Hydrogeology
Locate Nearby
Water Wells
Figure 1. Uncontrolled waste site inventory methodology.
Table 1. Data Sources for Uncontrolled
Site Inventory and Prioritization
Aerial photographs
Local and state health and conservation
agency records
Environmental atlases
Government publications on hazardous waste
sites
Historic resources (newspapers, directories,
fire insurance maps, plat books, industrial
surveys)
Interviews with public officials
Public call-in campaign
Engineering data and reports (soils tests,
boring logsl
County soils maps
USGS publications (especially the geologic
Quadrangle series)
Topographic maps
Geologic maps and reports in professional
journals
from the matrices can be used to select
priority sites for further testing or referra
action.
Greatest attention is given to those
sites that could impact either public oi
private drinking water supplies. The rank
ing scheme is based on the assumptior
that any site could contain hazardous
waste because of past unregulated waste
disposal practices. Rank is assigned ac
cording to potential impact on humar
health or drinking water rather thai
toxicity or quantity of waste, because thi
chemical composition of the waste i;
generally unknown at this stage of thi
investigation.
The five basic steps that are follower
for the inventory and ranking of sites are
Site Identification: Interpretation of his
torical aerial photographs, a searcl
of agency records, and a public call
in campaign.
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Site Characterization: Refinement/
confirmation of information through
interviews with local officials, resi-
dents, and industrial representatives;
review of agency files, street director-
ies, tax records, and historic docu-
ments. Location of water supplies in
close proximity to sites.
General Geologic Analysis: Develop-
ment of general hydrogeologic in-
formation on depth to groundwater
and bedrock hydraulic gradient, the
character and permeability of the
overburden.
Hydrogeologic Hazard Analysis: Evalua-
tion of sites for potential impact of
leachate on nearby water supplies
and human populations based on
geologic conditions.
Application of Methodology to Rank Sites:
Ranking of sites according to land
use, geology, and proximity to water
wells.
The key to the successful implementa-
tion of this type of program is the careful
organization and integration by qualified
individuals of all the critical resources
that might be overlooked or ineffectively
utilized in a less comprehensive effort.
Involvement of personnel from all affected
or peripheral agencies is strongly recom-
mended.
Procedures
Site Identification and
Classification
The site identification methodology
uses historical black and white aerial
photographs in stereographic pairs as the
data base to search for unknown sites
and to delineate accurate site boundaries.
Recommended criteria guide the photo-
interpreter in distinguishing between
waste disposal and fill areas. The photos
also supply information on periods of
operation and impacts on natural features
and nearby residents.
While these photographs serve as the
primary source of information on site
locations and activity, they must be
supplemented by researching old records,
conducting interviews, and by a public
call-in campaign. These secondary
sources, when used without photo anal-
ysis, are often insufficient for locating
sites and for determining boundaries,
periods of operation, and potential im-
pacts. The integration of all available
resources is the key to accurate site
identification and provides the most com-
plete profile of site activity.
Once sites have been initially identified,
it is important to verify the type of activity
noted on the aerial photographs. Inter-
views with municipal and public works
officials and representatives of industry
and a search of agency records are the
best means of confirming waste disposal
activity. Local residents are contacted
only after other sources have been re-
viewed. Once waste disposal locations
are confirmed, a careful search for private
and public water supplies within specified
distances of the sites is undertaken.
For both the site characterization and
water supply location phases, it is impor-
tant to contact individuals with detailed
knowledge of municipal records and
personnel who have worked in the munic-
ipality for a number of years. Employees
or board members who regularly conduct
field inspections often can provide valu-
able information.
Regional Hydrogeologic
Analyses
At the same time the inventory of sites
is being conducted, a general geologic
analysis of the entire region under study
should be done so that sites can be
evaluated and ranked according to poten-
tial impact on nearby residents and
surface and groundwater drinking water
supplies. This analysis also provides
useful information for site-specific stud-
ies conducted during later phases of the
project.
The principal products of this regional
hydrogeologic analysis are maps of the
surface of the underlying bedrock, the
surface of the water table, and the
overburden thickness throughout the area
of interest. A regional map describing
overburden composition is also neces-
sary. This basic information permits a
general hydrogeologic analysis of factors
directly influencing the production, con-
tainment, attenuation, or migration of
leachate. These factors generally involve
the groundwater system, the soil or rock
permeability, and the structures within
the overburden or rock that control either
the direction of movement, rate of move-
ment, or local concentrations of fluids. In
most cases, landfills or old dumps will be
found in unconsolidated soils or over-
burden, but occasionally the character of
•the local bedrock is also significant. The
critical factors must be evaluated within
the particular region under study.
The detail and accuracy of the geologic
interpretations will depend on the quality
and types of available information, as
well as on the complexity and variability
of surficial and bedrock geology. The
information needed requires a compre-
hensive review of published literature,
the location and collection of unpublished
data, development of both regional and
site-specific groundwater models, and an
integrated analysis of the geologic/
historic information preserved on aerial
photographs. Because there may be
valuable geologic information contained
on aerial photography, it is recommended
that the geologic and aerial photographic
analysis be closely coordinated and inte-
grated. Sources commonly used in the
development of a geologic data base for
both general or site-specific geologic
models are geologic maps and reports,
county soils maps, aerial photographs
and topographic maps, and engineering
data from public or private agencies or
firms.
Once a site has been identified and all
available information compiled from his-
toric aerial photographs and records, a
hydrogeologic ranking is assigned based
on the best available surface and sub-
surface information. Since this study does
not attempt to deal with the comparative
risks associated with specific chemical
substances but rather with the hydrogeo-
logic conditions that control the migration
of fluids under typical geologic circum-
stances, direct contamination of ground-
water or dwellings near the site is
considered the primary concern. This
approach dictates that sites with private
or public water wells close by should
receive the highest priority.
Ageologic ranking sheet was developed
to allow a subjective but practical compari-
son of high, intermediate, and low hazard
site hydrogeology. It also serves to docu-
ment the information and the process by
which the ranking is accomplished. As
such, it becomes a valuable part of the
data base to be used for reference and
possible revision or updating. The system
requires that knowledgeable decisions be
made by a hydrogeologist familiar with
the local geologic conditions.
Application of Methodology to
Rank Sites
In general, studies that deal with the
analysis and prioritization of known haz-
ardous waste sites where a great deal of
specific information is available on site
history, contents, and hydrogeology, rank
the sites on the basis of four variables—
waste content, land use, proximity to
water supplies and hydrogeology. For the
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purpose of an inventory of sites, where
little is known about the composition of
the waste contained in most sites, it is
impossible to rank the sites on the basis
of waste content for further investigation.
Sites can be classified as to kind of
activity and then ranked according to land
use, potential hazard in terms of geology,
and proximity to water supplies.
Once values have been assigned in all
of the separate ranking categories, a
matrix is constructed to establish final
site rankings. In Monroe County only
confirmed dumps/landfills, junkyards,
and lagoons were included in the matri-
ces, since information on the remaining
sites was too limited to justify further
investigation. However, records on those
sites were maintained in the event that
more information became available at a
later date.
Since little is known at this stage about
the waste contents of most sites, the
assumption is made that any confirmed
disposal site may contain hazardous
waste. It is the potential impact of
assumed hazardous wastes, then, that is
evaluated by using the matrix. The matrix
itself combines the variables considered
most important for the evaluation of
potential impact in the particular area
under study. Once all sites within a county
or municipality are assigned a priority
ranking, referrals are made to appropriate
agencies for site-specific action; water
supply owners, well owners and site
owners are notified.
Conclusion
The methods outlined in this report are
a suggested approach based on the experi-
ence of one county. Other local govern-
ments undertaking a similar study can
adapt the approach to meet local needs
and conditions. While the procedures
described apply to conducting a general
inventory, the basic approach can also be
used to investigate individual sites. Appli-
cation of the procedures will reduce the
expense of costly drilling and testing
programs by focusing resources on the
most critical sites.
Ann B. Nelson and Louise A. Hartshorn are with Monroe County Environmental
Management Council. Rochester. NY 14614; and Dr. Richard A. Young is with
State University of New York, Geneseo, NY 14451.
Roy B. Evans is the EPA Project Officer (see below).
The complete report, entitled "A Methodology to Inventory, Classify, and Prioritize
Uncontrolled Waste Disposal Sites," fOrder No. PB 84-120 153; Cost: $ 14.50,
subject to change) will be available only from:
National Technical Information Service
5285 Port Royal Road
Springfield, VA 22161
Telephone: 703-487-4650
The EPA Project Officer can be contacted at:
Environmental Monitoring Systems Laboratory
U.S. Environmental Protection Agency
Las Vegas, NV 89114
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