United States
Environmental Protection
Agency
Research and Development (481)
Solid Waste and
Emergency Response (5102G)
EPA/542/F-99/028
November 1999
Alternative Covers Subgroup
RTDF
Current RTDF
Action Teams
Bioremediation Consortroin
ONERT SoMIetals Action
Team
Permeable Reactive
Barriers Action Team
Ph\ tort-mediation of ,
Organics Action Team
Sedimeiifcs Remediation '_
Actton.Teain
The Alternative Covers Subgroup was formed by the
Phytoremediation of Organics Action Team to demonstrate that
alternative earthen covers (e.g., evapotranspiration and capillary
break systems) can be a cost-effective solution for a number of
waste disposal facilities in the United States. Through its Alternative
Cover Assessment Program (ACAP), the Subgroup's goal is to
develop basic design manuals and numerical tools for site owners,
design engineers, and regulators in evaluating the performance of
alternative earthen covers. The objectives of the ACAP are to:
• measure the performance of various landfill cover designs,
• improve the numerical modeling capabilities and monitoring
methods,
• develop regional design guidance, and
• provide a cooperative mechanism for program funding and
direction.
ACAP Activities
ACAP is a four-phase effort. Phase I consists of an initial review of
current data collection efforts of various facilities and the capabili-
ties of numerical modeling. Phase II will involve the design,
construction, and operation of a network of at least 10 cover testing
facilities. In Phase III, the Subgroup will combine Phase II field
results with improved numerical models to predict the long-term
(over 500 years) performance of alternative cover systems at
selected field-test sites. The final phase, which is expected to begin
in 2003, will involve development and dissemination of comprehen-
sive documentation on alternative cover systems and guidelines on
evaluating their use at specific sites.
How Field Tests Will Be Conducted
Facilities will be located at, or near, disposal sites with differing
geology and climates. At each location, one or more full-scale (in
depth) cover designs will be constructed in 200 m2 water-balance
lysimeters. Vadose zone monitoring and biological and climatolog-
ical observations will provide data concerning the movement of soil
moisture, local climate conditions, and plant community activities.
Field efforts will focus on directly measuring the performance of the
tested covers and movement of ground water through the various
cover designs. All sites will be monitored through uniform methods
using similar technologies. Climatic parameters used for perfor-
mance testing will include wind speed and direction, air tempera-
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ture, precipitation, solar radiation, humidity, and
snowfall/snowpack. Plant-related parameters will
include minirhizotron sampling (photographic
imaging through transparent tubes inserted into the
soil) of root distribution, a leaf area index, and plant
biomass. Soil parameters will include:
• Lysimeter drainage (tipping bucket recorder,
stage recorder, and dosing siphon);
• Continuous integrated water content
measurements (electrical resistance, capacitance,
and reflectance);
• Electronic soil-water pressure (tensiometer, heat
dissipation, and gypsum block);
• Gas sampling, where appropriate;
• Soil temperature profiles, where appropriate;
and
• Drainage water quality.
Accomplishments
The Subgroup has completed Phase I work on iden-
tifying research facilities with alternative cover
systems and reviewing current numerical modeling
capabilities, and the summary report is being
prepared. The report will be available on the
Phytoremediation of Organics Action Team's home
page on the RTDF web site (www.rtdf.org).
The Subgroup has begun Phase II work, which
involves designing, constructing, and operating a
network of alternative cover facilities and making
modifications to the current numerical models. The
Subgroup expects to construct test facilities at up to
nine sites in 1999 and at additional sites in 2000.
Subgroup Members
Membership in the Alternative Covers Subgroup
and participation in the ACAP is open to representa-
tives of industry, government, and academia who
are interested in developing and validating the use
of alternative earthen covers for the isolation and
containment of pollutants. Organizations currently
represented in the Subgroup include:
Chevron Corporation
Desert Research Institute
Goodyear, Inc.
PPG, Inc.
Science Applications International Corp.
Union Carbide
California Environmental Protection Agency
California Integrated Waste Management Board
California Regional Water Quality Control Board
California Regional Water Resources Control Board
City of Cincinnati
Pacific Northwest National Laboratory (PNNL)
U.S. Department of Energy
U.S. Environmental Protection Agency
University of'Wisconsin
Subgroup members get together frequently via
conference call to share information and discuss
progress of activities. Formal meetings are held as
needed and are often co-located with other related
conferences. Specific field activities are supported,
through Cooperative Research and Development
Agreements (CRADAs), with funding and/or in-
kind services from participating Subgroup members.
CRADAs are designed to encourage partnerships
involving government agencies, private industry,
and academia.
For More Information
More information on the Alternative Covers
Subgroup, including summaries of meetings and
conference calls, is available on the
Phytoremediation of Organics Action Team's home
page on the RTDF web site or by contacting:
Steve Rock
U.S. Environmental Protection Agency
National Risk Management Research Laboratory
26 West Martin Luther King Drive
Cincinnati, OH 45268
Tel: 513-569-7149
Fax: 513-569-7105
E-mail: rock.steven@epa.gov
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