technical BRIEF
&EPA
a
www. epa. gov/nhsrc
The Threat Ensemble Vulnerability Assessment
(TEVA) Research Program: Tucson Water Study
Software helps water utilities be better prepared for
contamination threats
EPA's Threat Ensemble Vulnerability Assessment and Sensor
Placement Optimization Toolkit software (TEVA-SPOT) can be
used to assist water utilities by:
•	Recommending key sensor locations (e.g., water quality
monitoring locations) in water distribution systems
•	Identifying critical water utility and public health response
times to minimize impacts
•	Identifying vulnerable areas in water distribution systems
•	Helping improve water distribution system models
TEVA-SPOT software can be used to determine the number and
location of sensors that are needed to support a contamination
warning system. The location of online sensors can be optimized
to help achieve such a system's primary goal: to detect contamination incidents in time to mitigate
public health and economic consequences. TEVA-SPOT can also be used to meet additional design
objectives — for example, minimization of costs, detection time, exposure to contaminants, and the
spatial extent of contamination. In addition, the software can be used to demonstrate the importance
of a fast response to a detected contamination incident.
In order to use TEVA-SPOT, it is necessary to have utility-specific input. Often, through the
application of TEVA-SPOT, improvements to the distribution system models benefit the utility
in other projects as well.
Tucson Water Utility Study
Tucson Water is an innovative and advanced municipal
drinking water system that serves nearly 700,000
customers. Through an EPA Environmental Monitoring
for Public Access and Community Tracking (EMPACT)
grant, online monitors have been providing near real-
time water quality data to the public for several years.
Tucson Water is currently considering the expansion of
the online monitoring program to meet its security
objectives.
EPA began TEVA work with the Tucson Water utility in
early 2005. The goal of the Tucson Water TEVA study
was to identify new and/or existing EMPACT locations
that could be used for monitoring for contamination incidents. Additionally through interaction with
Tucson Water, as well as with other water utilities, EPA has been able to develop, test, and refine
TEVA methodologies.
In order to use TEVA-SPOT, multiple pressure zone models had to be integrated into a single system-
wide model. While separate pressure zone models are sufficient for many utility needs, water security
EPA's
National Homeland Security

Research Center (NHSRC) is


researching ways to protect the nation's
drinking water sources and distribution
centers and to ensure
the safety of

wastewater collection,
treatment, anc

disposal procedures. This research is
part of EPA s larger effort to improve
the security of drinking water and
v/astewater treatment systems
This task was assigned to EPA by


the 2002 Presidential Budget and by
Homeland Security Presidential
Directive (HSPD) 7, which mandates


protecting water resources from source
water through use.
discharge.
treatment,
and

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analyses require a systems-engineering approach, focusing on the entire distribution system as a
whole. EPA is assisting Tucson Water in the development of the integrated model.
Tucson Water is evaluating how to effectively use the designs recommended by TEVA-SPOT
to create and implement a sustainable and cost-effective contamination warning system. In addition
to the number and placement of sensors, Tucson Water is also evaluating vulnerability information
provided by EPA researchers to better understand the sensitivity of response time in mitigating public
health impacts following a contamination event.
For more information, visit the NHSRC Web site at www.epa.gov/nhsrc and the TEVA Research
Program page at http://www.epa.gov/nhsrc/water/teva.html.
Technical Contacts: Robert Janke (513) 569-7160, ianke.robert@epa.gov
Regan Murray (513) 569-7031, murrav.regan@epa.gov
Communications Contact: Kathy Nickel (513) 569-7955, nickel.kathv@epa.gov
July 2007
EPA/600/S-07/020

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