Farm and Home Biosecurity
Consumer/General Public and Livestock/Row Crop Producer
Minimizing Security Risks For Public Water Systems
September’s acts of airline terrorism and the subsequent anthrax threats
have focused the attention of water system managers and operators on security
issues. Adequate security has long been part of the responsibilities of water
system managers, typically through the use of fences, locks, and, in some
systems, intrusion alarms and security cameras. However, the events of last fall
have led many to question whether their security measures are adequate.
A water system could be an attractive target to a terrorist or a vandal. The
potential for causing panic among the public is great due to the essential
nature of safe drinking water and the public’s trust in their drinking water
systems.
However, there are significant technical challenges in being able to
effectively contaminate a public water system. The large volumes of water in a
source and distribution system, the barrier that the treatment plant provides,
the disinfectant residuals typically present in the water, and the unpredictable
nature of water use and distribution system hydraulics all act to reduce the
effectiveness of a malicious act against a water system. It would be more likely
for a terrorist to use some other means of a biological or chemical agent in a
distribution system such as a building’s ventilation systems, or, as in the
anthrax cases, the U.S. postal system.
On October 18, 2001, the American Water Works Association (AWWA) issued a
news release, which spoke to these issues. In that new release, AWWA Executive
Director Jack Hoffbuhr stated “Most water systems have so much water and such
effective treatment mechanisms, that anything less than many tankers full of
dangerous agents would be diluted and easily neutralized. It is hard to imagine
that anyone would have the ability to deliver such quantities effectively and
without detection.”
This statement implies that a water source is less vulnerable than other
parts of the water infrastructure - for example, the distribution system.
However, this does not mean that water system managers or operators should be
complacent. There is a danger that local vandals could exploit the public’s
heightened concerns and attack a water system. A water manager should take every
practical and prudent step to make such vandalism less likely. In this effort, a
manager has a great deal of technical guidance available to him from such
sources as the AWWA, the AWWA Research Foundation, EPA, and reprinted articles
and video tapes made available by the Arkansas Department of Health.
There is a highly developed methodology for analyzing the vulnerabilities of
facilities and identifying ways to lower risk. The first step is for a manager
to analyze the various facilities and equipment that make up the water system
and rate each as to its importance to the mission of delivering safe water and
also its vulnerability to attack. A vulnerable part of the system is one where
the consequence of a failure is high. For instance, since a chlorine gas leak
could cause injury and death of nearby residences, as well as interrupt the
disinfection process, the gas chlorine feed system is a highly vulnerable part
of a water system. A water manager should then focus on securing (hardening)
those parts of the system that are both critical to the operation and highly
vulnerable.
The second step is to reduce the consequence of a failure or an attack on the
highly important and vulnerable parts of the system. Some important facilities
can be made less vulnerable by either providing backup equipment or changing the
equipment or design so that a failure is not as dangerous. For example, a
particular pump may be critical to the functioning of a water system. However,
redundant pumps make the system less vulnerable to that pump’s failure. As
another example, the vulnerability of the gas chlorine disinfection process
could be lowered by changing to a hypochlorite system of an electrical/salt
solution chlorine generation system. In either case, the danger of a chlorine
gas discharge is eliminated and reduces the consequence of an attack on the
chlorine system. However, the danger of a loss of disinfection remains.
If this logic is applied in the context of contamination from terrorism or
vandalism, many small systems will find that perhaps their most critical and
most vulnerable point will be the security of the storage tanks in the
distribution system. Not only are the tanks usually vital to the system’s
operation but the water quality in the tank could most easily be compromised by
a terrorist or vandal accessing the tank through a hatch or manway. This act
would by-pass most of the treatment barriers except for the residual
disinfectant in the water. Also rating high in both vulnerability and importance
to most water systems, as explained earlier, is the chlorine feed system.
Developing greater security for the gas chlorine installations should be a
priority.
Depending upon the specifics of each system, there may be other areas that
also would be rated highly vulnerable and highly vital to water quality or
system operation.
The third step in lowering the risk of terrorism or vandalism is to increase
security, or harden, those identified vital parts of the system. There are three
parts to hardening a particular part of the system. These are: 1) deny or delay
the criminal’s access; 2) detect the incidence of a terrorist act; 3) respond
to the incident as quickly as possible.
Water system personnel have many tools available to them to properly address
each of these three parts. The challenge is to properly balance the need for
security versus the responsibility to make efficient use of the system’s
financial resources.
First, the water system manager should make sure that facilities have prudent
measures in place to deny or delay access of unauthorized personnel to the
facilities. For small water systems, this will most likely mean that pump
stations and tank sites are fenced and locked. Particular emphasis should be
placed upon making sure that tank hatches are securely locked. Also,
chlorination stations should be locked, fenced, and perhaps equipped with
intrusion alarms that are connected to the system’s SCADA system, if one is in
use. Larger systems that operate treatment plants should take measures to ensure
that only authorized individuals have access to the treatment plant. A formal
procedure should be set up to approve visitors beforehand and escort them while
they are in the treatment plant.
It is much more difficult to control access to water supply lakes. However,
this is usually a low vulnerability part of the system due to the dilution
factor, the large quantity of agent that would be needed to contaminate the
water, and the fact that the treatment processes would act as a barrier between
the contaminated lake and the customers.
The second part of hardening a facility, detection, can be accomplished by
several methods. Modern SCADA systems allow for intruder alarms to be connected
to the system which can set off alarms whenever doors to pump stations or other
buildings are opened. It might even be possible for these same types of alarms
to be used to monitor the hatch lids of storage tanks or for motion detectors to
be installed on ladders and be connected to an alarm system. Also, some of the
current SCADA systems will allow for video cameras to be set up at vital
locations such as intake sites or tanks and have those views available to the
operator at a central monitoring station.
The technology is also available to allow continuous water quality monitoring
of the distribution system. Continuous chlorine residual monitors can be
installed and a signal provided to the SCADA system. Since most bio-terrorism
contaminants would deplete a chlorine residual, this type of system would allow
the water operator to react to a drop in the disinfectant residual. This type of
technology would most properly be placed on a main line downstream of
distribution storage tank.
Another important way to detect intrusion is to enlist the general public in
watching your facilities. This would probably take the form of signs at the
water supply lake or distribution system storage tanks that indicate what phone
numbers to call if suspicious activity is noticed at the supply lake or other
vulnerable facilities. These signs should not indicate what the facility is.
Rather, the signs should just indicate that no trespassing is allowed and give
the contact information for citizens to call to report suspicious activity.
Local police may also be enlisted to perform routine checks of tank sites and
other vulnerable facilities. An effort should also be made to enlist the
cooperation of neighbors of these facilities. They should be given names and
phone numbers of contacts at the utility and encouraged to call if they notice
suspicious activity near the facility. For systems large enough to have
treatment plants operating 24 hours a day, around-the-clock staffing of the
plant should be strongly considered if not already in place.
This step of monitoring the water system’s operation and water quality and
detecting incidents of crime will probably present the water manager the
greatest challenge of balancing the need for security versus the responsibility
to efficiently and prudently utilize the finances of the water system. The
Environmental Protection Agency has indicated that many costs associated with
enhancing security can be financed through the State Revolving Fund (SRF).
The third and last step in lowering risk, or hardening a facility, is to
lower the response time in the case of detection. Some ways to improve response
time are to make sure that local police, residents nearby vulnerable facilities,
and perhaps others, all have the correct phone numbers to contact the water
system management at night and on weekends. Also, the water system management
must make sure that they have the proper contact information for police and
first responder groups. Included in this information should be the contact
information for the County Emergency Management Coordinator.
It is impossible for the water system manager to absolutely prevent the
system from being attacked by a terrorist or vandal. However, it is the
responsibility of the management to lower the risks to the water system. The
Arkansas Department of Health has compiled a list of items to check when the
water manager attempts to evaluate the system. This tool is available to
managers and is to be added as Appendix C of the “Arkansas Public Water System
Compliance Summary”. Also, the ADH is obtaining video tape copies of recent
security related teleconferences sponsored by AWWA. These are available to be
borrowed and reviewed by water managers. There is also a significant amount of
technical information available to waterworks managers by visiting the internet
home pages for AWWA, AWWARF, and EPA. Also, the Arkansas Department of Health
has compiled a list of email addresses of our water systems and their managers.
We will be able in the future to use this address list to forward any terrorism
warnings that we receive from the Federal government. Please contact your
District Engineer or Specialist and verify that we have the correct email
address for you or your system.
In analyzing the system and taking steps to lower risk, the manager should
remember the elements of lowering risk which are: Assess, Lower Consequence,
Delay, Detect, and Respond.
Jeff Stone, P.E., Engineer Supervisor
Division of Engineering - Arkansas Department of Health
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