United States
Environmental Protection
Agency
Municipal Environmental Research
Laboratory
Cincinnati OH 45268
Research and Development
EPA-600/S2-83-112 Dec. 1983
&EFW Project Summary
Evaluation of a Containment
Barrier for Hazardous Material
Spills in Watercourses
Thomas N. Blockwick
»/
This project was undertaken to design,
develop, and evaluate a physical barrier
system to contain accidental
concentrated spills of insoluble hazard-
ous materials in water. The system was
to be effective in flowing water, light-
weight, easily transportable, and cap-
able of being deployed by a minimum
number of trained personnel.
A prototype barrier designed to meet
the above criteria was constructed of a
flexible, fiber-reinforced plastic curtain
with air-inflatable flotation. To prevent
escape of polluting materials from the
contained mass of water, the bottom of
the barrier is sealed against the bottom
of the watercourse with a liquid-filled
bladder held in place with several
anchors. The ends of the curtain are
laced together to give a cylindrical
shape.
Full-scale field testing of the barrier
system was initially conducted in 1971
and 1972 to evaluate deployment
techniques, to determine the amount of
leakage from the barrier by using dye as
a simulated hazardous material, and to
measure the loads imposed on the
barrier by currents. Testing was again
conducted in 1976 with an improved
barrier system incorporating changes
based on the earlier tests.
As a result of the field tests, it was
concluded that a properly designed
barrier system could contain spills and
leaks that were not rapidly dispersed
into the water environment. Such spills
would include releases of concentrated
insoluble hazardous substances that
pool on or near the bottom. But the
studies also demonstrated that the
hazardous material barrier (HMB) had
serious shortcomings, the greatest
being its sensitivity to currents, the time
required for deployment, and weight-
related handling difficulties. Rapid
technological advancements in plastics
and their fabrication, coupled with the
experiences gained from this study,
may now make it possible to construct a
barrier that can be deployed more
rapidly and with less difficulty.
Though this report is being issued
several years after project completion,
information on the study was presented
at the 1972 National Conference on
Control of Hazardous Materials Spills,
and technical advice has been provided
on this topic to EPA Regions making
inquiries. We hope that the release of
the report will stimulate those in the
user community that may want to
further the development of this
concept.
This Project Summary was developed
by EPA's Municipal Environmental
Research Laboratory, Cincinnati, OH,
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).
System Description
The barrier is constructed of a highly
flexible, fiber-reinforced plastic material
that can be deployed around a spill source
such as a sunken barge, rail car, ortanker
truck containing concentrated insoluble
hazardous materials that pool on or near
the bottom of the waterbody.
Incorporated into the barrier are an air-
inflated flotation collar that supports the
barrier and a liquid-filled bladder that
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seals the bottom of the barrier to the
bottom of the waterway in which the
barrier is deployed. The ends of the
barrier are laced together before
deployment to give the cylindrical shape
needed for the confinement of a spill.
Figure 1 shows the barrier fully inflated
on the water surface.
Five explosive embedment anchors are
used by divers to moor the barrier in
place. These anchors were selected
because of their very high holding power-
to-weight ratio and the speed with which
they can be installed relative to
alternative anchoring systems. Each
anchor assembly weighs approximately
100 Ib in the ready-to-fire configuration.
Equipment used in deployment
includes special devices for pulling the
barrier to the bottom and mooring it to the
anchor pendants, equipment for inflating
the air bladder and filling the water
bladder, vessel(s) for deploying the
barrier, and marker buoys and anchors
for temporarily mooring the barrier until it
can be permanently anchored.
A small boat with at least a 1000-lb
capacity is required for installation of the
system. The boat should be equipped with
at least a 5-hp outboard motor if it is used
to deploy the barrier. If the barrier is to be
deployed in a watercourse where there is
a current, then a larger, more powerful
motor is required for towing of the barrier.
Prototype Field Tests
Three field tests were conducted with
the prototype barrier between October 1,
1971, and April 30, 1972. The first test
was conducted in Sugar Grove, West
Virginia, to evaluate the barrier and
deployment techniques under still water
conditions. Deployment, mooring, and
anchoring of the barrier were no problem
under the still water conditions of the
lake. Some mechanical problems were
encountered in opening the tapes holding
the barrier bundle together, and some
minor leaks were observed in the
flotation bladder. Dye tests with
Rhodamine-B as a simulated spill demon-
strated that nodye leaked from the barrier
over a 24-hour period.
The second test was conducted on the
lower Potomac River, southeast of
Colonial Beach, Virginia. This site
afforded the depth, currents, and bottom
conditions required to subject the barrier
and deployment procedures to more
severe conditions. Positioning and
mooring the barrier at the test site did
prove more difficult in the river current (1
knot). Unfortunately, wind, waves, and
adverse weather conditions caused the
Figure 1. Fully-inflated barrier.
barrier to unfurl prematurely and forced
cancellation of this trial before any
testing could be carried out.
The site of the third trial was near Lake
Worth Inlet, Palm Beach, Florida. This
location was considered ideal since there
were tidal currents of 1 to 2 knots and
underwater visibility was excellent. The
purpose of this test was to observe
certain stages of deployment and aspects
of the in-place barrier. Although mooring
and anchoring were completed rapidly,
the currents at this site, and perhaps
undiscovered damage during the earlier
tests, caused the barrier to tear quite
extensively and ultimately to feather in
the current. The suspected pattern of
failure is described in the full report.
Following the 1972 field tests, recom-
mendations were made to construct a
new, strengthened barrier, and in 1976,
field testing and evaluation were con-
ducted at the formerly used site in Palm
Beach, Florida, to benefit from the experi-
ence of that previous test.
Current velocities were measured
during the field testing to determine the
effects of the tidal currents on the
configuration and integrity of the
improved barrier. Afluorescent dye tracer
study was attempted to evaluate the
ability of the barrier to contain a
simulated spill. But this procedure could
not be completed because the current
flow caused the barrier to collapse into
itself on the surface, while the bottom
bladder failed to maintain a seal with the
bottom. Lead weights were subsequently
used to keep the bottom seal in place, but
the flotation collar continued to collapse
in the current.
Recovery of the barrier for reuse, a
necessity if it is to be cost-effective,
proved in all tests to be a time-consuming
and tedious operation, even when using
heavy equipment.
Conclusions and
Recommendations
The hazardous material barrier system
can be a viable countermeasure against
spilled hazardous materials. Field tests
indicate that deployment of the barrier in
currents faster than 1 knot is not
recommended, since the design
configuration cannot be maintained
effectively and reliably. With currents
above 1 knot, the barrier loses its shape
and tends to close in on itself.
The self-embedment anchoring system
used to moor the barrier is extremely
effective. The pull-down system used for
deployment of the barrier worked well,
but a more efficient mechanical handling
system is needed for launching and
recovering the barrier. Deployment of the
barrier can be accomplished in time to
contain spills that are not rapidly dis-
persed or where a significant amount of
the pollutant remains at the source 8 to
12 hr after the barrier system arrives at
the scene of the accident..
Recommended system changes
include: (1)the use of a stronger or multi-
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ply material at critical points of the
barrier; (2) the use of non-kinking hoses
for inflation of the flotation collar and for
filling of the liquid bladder; (3) the design
of a procedure and a system for draining
the bottom seal bladder; and (4)
consideration of mechanical aids that will
eliminate or reduce the need for divers.
The full report was submitted in fulfill-
ment of Contracts No. 68-01-0103 and
68-03-2168 by Samson Ocean
Systems, Inc., under the sponsorship of
the U.S. Environmental Protection
Agency.
Thomas N. Blockwick was with Samson Ocean Systems, Inc., Boston, MA 02110.
Ira Wilder is the EPA Project Officer (see below).
The complete report, entitled "Evaluation of a Containment Barrier for Hazardous
Material Spills in Watercourses." (Order No. PB 84-123 942; Cost: $10.00.
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:
Oil and Hazardous Materials Spills Branch
Municipal Environmental Research Laboratory—Cincinnati
U.S. Environmental Protection Agency
Edison, NJ 08837
•trUS GOVERNMENT PRINTING OFFICE 1983-759-015/7246
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Environmental Protection
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