A Dynamic Systems Simulation Approach to
Risk Mitigation for Critical Infrastructure at
the United States Military Academy
Major Marc A. Lee
Assistant Professor
Department of Systems Engineering
United States Military Academy
E-mail: Marc-Lee@ usma.edu
Telephone : (845) 938-4399
FAX : (845) 938-5919
Keywords : Dynamic Systems Simulation, Management Flight
Simulator, Critical Infrastructure, Decision Support System
ABSTRACT
The United States Military Academy at West Point is responsible for the
education and training of the United States Corps of Cadets - future leaders in
our Nations defense as Army officers. Like many U.S. Military installations, West
Point provides its own freshwater management for consumption by the cadets,
faculty, and staff. In recent years, the freshwater supply at the Academy has
reached critical levels - causing concern about the Academy's ability to conduct
effective operations during peak summer months. As a result, the freshwater
conservation plan was recognized as needing improvement. With the use of
Systems Dynamics a Management Flight Simulator was built to analyze the
current system and serve as a decision support system for future operations.
INTRODUCTION
The United States Military Academy at West Point, like many other U.S.
Military posts, manages its own freshwater resources for consumption during
daily operations and by the military members living on the installation. The
Directorate of Housing and Public Works (DHPW), Natural Resource Division, is
tasked with the operation and upkeep of all freshwater treatment and delivery
systems. Further, the Natural Resource Division has oversight of the many
freshwater sources on the West Point military reservation that provide the
untreated water essential for the daily operations at the Academy.
A prolonged period of below average precipitation in the Hudson Valley
during the summer of 1999, combined with a light snowfall the previous winter,
caused significant concern about the freshwater supply at the United States
Military Academy. The peak demand of the summer months and extensive forest
fires on and around the Academy reservation caused the freshwater supply at
the Academy to reach critical lows in the late summer months.
As a result of the critical levels of freshwater, the Directorate of Housing
and Public Works implemented a phased water conservation plan to mitigate the
risk of catastrophic shortages that might inhibit the Academy's ability to complete
mission essential training for the freshmen and sophomore classes. As
conservation measures began, the picturesque landscape of the West Point's
academic area began to tinge with brown.
Though the water conservation plan proved successful, the DHPW was
concerned about the validity of their conservation plan and timing of the
implementation of each phase. DHPW’s internal assessment of the summer's
events concluded the following:
¢ The water conservation plan was implemented later than prudent
Criteria to trigger the conservation plan was not clearly identified
¢ Criteria to escalate the phases of the conservation plan was not clearly
identified
¢ The conservation plan was heavily dependant upon the community’s
willingness to comply with unenforceable conservation measures
¢ The freshwater system was more vulnerable than previously thought
As a result of their concerns, the Directorate of Housing and Public Works
approached the Department of Systems Engineering for assistance in analyzing
the problem and recommending solutions. The project was accepted and
integrated into the Engineering Management Program in the form of an
undergraduate capstone experience. A four cadet, multidisciplinary team with
faculty mentor applied system dynamics simulation to the modeling of the West
Point freshwater system.
APPROACH
A Systems Approach using a traditional Systems Engineering Design
Process (SEDP) was the methodology chosen for the management and
monitoring of the project. The SEDP provides a framework for approaching
problems in a logical, systematic process. This framework guides the modelers
through a top-down, iterative, life-cycle approach to defining the problem,
generating alternatives, planning for the implementation of the best alternative,
and finally managing the project through completion. The SEDP is well suited for
System Dynamics in that it provides a framework to deal with large-scale,
complex, multidisciplinary problems that are not amenable to solution by single
functional engineers. Design is, by its nature, a creative process. The SEDP is
an organized approach to creativity that enables modelers to choose appropriate
“tools.” Systems Dynamics simulation was chosen as the appropriate “tool” to
assess the Directorate of Housing and Public Work’s conservation policies.
Figure 1 shows the Systems Engineering Design Process.
Systems Engineering Design
Process (SEDP)
Formulation of b=] Saga
Alternatives
Ae) Weer
Analysis of
Alternatives
ee |
Ic
Interpretation of
Alternatives
Figure 1 - Systems Engineering Design Process
PROBLEM DEFINITION
The initial statement of work as proposed by the Directorate of Housing
and Public Works was to provide an assessment of the DHP W's current water
conservation contingency policies and make recommendations for
improvements. To ensure the validity of the initial concept of proposed work,
stakeholders and stakeholder needs were identified.
STAKEHOLDER ANALYSIS
The purpose of stakeholder analysis is to identify those organizations,
communities and individuals who might be affected by the systems. This allows
for the refinement of the scope and bound of the problem and revision of the
problem statement to include greater resolution of the problem domain. Table 1
shows a summary of the stakeholders and their stake in the system.
Stakeholder Objective(s)
Directorate of Housing and | To provide clean and potable water to the
Client Public Works West Point community for on demand
consumption.
Chief, DHPW, Natural
Decision Maker Resources Division
To provide clean and potable water to the
West Point community for on demand
consumption.
Directorate of Housing and
Sponsor Public Works
To provide clean and potable water to the
West Point community for on demand
consumption
Capstone Team and
Facilitate learning/educational process and
Analysts Faculty Advisor provide the client with a worthwhile product
Users West Point community, Clean and potable water readily available
cadets, faculty and staff for consumption and use at any given time
Officer of the Directorate of | Water readily available for the maintenance
Customer Intercollegiate Athletics of athletic facilities and for consumption
during summer athletic camps
Department of Admissions | Sufficient water readily available to maintain
the West Point academic grounds in
Customer support of Academic Workshops and to
provide additional water to the surrounding
community for stimulation of growth
Town of Highland Falls To obtain sufficient quantities of water from
Partner the Popelopen watershed to stimulate
economic growth
Table 1 - Stakeholders and Stakeholder Objectives
SYSTEM CONCEPTUALIZATION
PHYSICAL COMPONENT
West Point's freshwater system is self-contained. The raw/untreated
water is obtained from the Popolopen-Queenboro Watershed, which lies entirely
on the West Point Reservation. On post, water treatment plants provide the
West Point community with potable water. The Lusk Reservoir treatment facility
is gravity fed from a series of lakes, while other treatment facilities have water
pumped into them. Once it reaches the treatment plants, the water goes through
a five-stage process for purification.
1. Flocculation - This stage serves two purposes: coagulation and
flocculation. Aluminum sulphate is added to the water as it enters the
accelator/flocculator. Gently revolving paddles cause the sulphate to form a
gelatinous substance that is filtered out as the water rises vertically to the exit
accelator. This stage frees the water of most of the suspended material. The
flocculation stage has a one-hour detention time.
2. Sedimentation - The sedimentation stage removes most of the
impurities of the water by sedimentation. Water is detained for a period of four
hours in the baffled settling basin. Alum is added to remove color, while a
descending floc sweeps turbidity and bacteria down with it.
3. Filtration - Rapid sand filters strain out the remaining bacteria and
suspended particles.
4. Dosing Pit- This tank provides a place where the filtered water can
receive chemical treatment before entering the clear well and going to the
consumer. Soda ash, fluoride, and a final dose of chlorine are all added to the
water.
5. Clear Well - The clear well provides a place where the water can be
tested. Daily chemical, bacteriological, and physical tests are necessary to
control the purification process, and required under the Safe Drinking Water Act.
Figure 2 below is a diagram of the Lusk Reservoir treatment plant. Other plants
are identical with some minor exceptions to the number of settling tanks.
Lusk Reservoir Treatment Plant
=| ae
Sectling Tawh 2 H © ng [
Ue Hus To bt tk a ied
Level Tanks
From bask O
Figure 2 - Lusk Resevoir Treatment Facility
Following treatment, water is transported to a series of tanks on the West
Point reservation. There is an alignment of treatment facility to storage tank to
consumer location that allows the reasonable economy of effort while providing
treated water. The systems does allow for the pumping of water between tanks
and facilities. For the purpose of distribution management, the consumer area is
divided into five levels. Table 2 shows the levels for distribution of treated water.
Target Hill Athletic Field Old PX Gray Ghost Housing Area
North Athletic Field Cemetary New Brick Housing Area
Daly Field BOQs/Five Star Keller Army Hospital
Clinton Field Fire Station Laundry Plant
Doubleday Field Dunover Court Housing Area Ski Slope
Plain Lee Road Housing Area
Buffalo Soldiers Field West Point School
Arvin Gym Band Housing Area
Waterfront Housing Old Brick Housing Area
Administrative Buildings
Visitor's Center
Child Development Center
New PX Complex
Olmsted/S pellman Hall Michie Stadium Shoppette/Class VI
Hotel Thayer. Lusk Area Housing Commissary
Academic Buildings Holleder Center Stony Lonesome |
West Point Club Lichtenburg Tennis Center Stony Lonesome II
Table 2 - Water Distribution Levels
Figure 3 shows the treated water distribution levels on the West Point Garrison
map.
Figure 3 - Water Distribution Levels (West Point Map)
The treated water is delivered to the consumer through an extensive
network of tanks and pipelines. Prudence dictates that the physical structure of
the entire delivery system not be fully described in the paper.
POLICY COMPONENT
The Directorate of Housing and Public Works has long had a phased
water conservation policy. Though seldom implemented, the policy has long
thought to be adequate enough to mitigate the risk of on-demand delivery of
potable water to all consumers. The three phases of the water conservation plan
are:
1. Phase | - Restricts the use of water for washing of paved surfaces,
privately owned vehicles, watering of residential lawns, and the use of
water for ornamental purposes.
2. Phase Il - Restricts the use of water for the filling/use of swimming
pools and the washing of all vehicles (government and private).
3. Phase Ill - Restricts the use of water for watering landscaping and
athletic field. Sets the maximum usage at 50 gallons per person per
day.
Unfortunately, many of the conservation measures in the phased policy
are relatively unenforceable in the West Point community. Despite a reasonable
expectation that most of the community will follow the guidelines for the sake of
doing what is best for the community and environment, DHPW does not have the
resource to monitor, enforce, and gather data on the success of the policies.
This lack of a feedback and analysis tool further hinders the ability to escalate
and trigger the phased conservation policy.
MODEL DEVELOPMENT
The development of the Systems Dynamics simulation was conducted in
PowerSim .
DATA COLLECTION
Fortunately, the Directorate of Housing and Public Works maintains an
extensive repository of water utilization data over past years. However, the
utilization data was an aggregate, by level, of total usage. Unlike the civilian
sector, West Point does not meter usage at residences or many facilities at the
Academy. This presented two problems - 1) determining the percent of the
aggregate usage that each logical grouping of consumers used periodically and
2) determining the expected percent reduction of usage for each phase of the
conservation plan. The first was determined through a statistical analysis of
relative usage for number of families, people in the organization, or facilities. The
second was determined through statistical analysis from the few measurable
usage areas on the West Point grounds.
Originally, customer usage was modeled as a stochastic element within
PowerSim®. However, with the need for responsiveness to changing customer
trends, the model was revised to incorporate a time series forecast for each level.
An attempt to use average rainfall data for the Hudson Valley region to
determine the levels of the numerous freshwater sources was made. However,
the data did not exist to show the correlation between rainfall, runoff, and
changes in levels of the freshwater sources. Thus, the levels of the sources
became a needed input by the user to initiate a run of the simulation. Actual
levels are measured bi-weekly by the office of the Directorate of Housing and
Public Works. This decision provided greater accuracy of initial values for each
run to the simulation.
MODEL STRUCTURE
The system was broken into sub-systems for each level and treatment
facility. This allowed for an organized development pallet to facilitate model
maintenance and troubleshooting throughout the model's life-cycle. Each level
was neatly organized and labeled. Figure 4 shows an example structure for
Level 2 of the freshwater system.
Example Structure for Level
.evel 2 Water Distributior
Figure 4 - Example of Level Structure
Example Structure of
Treatment Facility
‘Lusk Reservoir Water Treatment Plant
\e’ 5
Figure 5 - Example Treatment Facility Structure
Figure 5 shows an example structure for a treatment facility.
USER INTERFACE
The user interface was modeled to allow for visual monitoring of all key
aspects of the systems to include built in triggers to alert the user of approaching
and bypassed thresholds. There are two main components of the user interface-
1) Monitors and 2) Controls.
After entering the current levels of the freshwater sources on the West
Point reservation, the user can run the simulation and monitor levels in the
treatment facilities and storage tanks. Figure 6 shows an example of a treatment
facility monitor.
Example of Treatment Plant
Monitor
Lusk Reservoir Treatment Plant
Figure 6 - Example Treatment Facility Monitor
Upon treatment the water flows to various storage tanks upon the grounds.
Figure 7 shows an example of storage tank monitors.
Example of Storage Tank Monitors
Figure 7 - Storage Tank Monitors
In keeping with the initial purpose of the model, to validate the phased
conservation policy at the Academy, controls are used to toggle the appropriate
phase of the policy. Figure 8 shows an example control panel for the
conservation policy.
Example Conservation
Plan Controls
Figure 8 - Conservation Plan Controls
Additionally, controls were designed to allow the user to replicate an
increased or decrease output from the treatment facilities. Figure 9 shows an
example treatment facility control panel.
Example of
Treatment P lant
Control Panel
Figure 9 - Treatment Facility C ontrols
MODEL IMPLEMENTATION
MEETING ORIGINAL NEEDS
The model was delivered through an evolutionary delivery cycle, allowing
the users to provide input to development on multiple occasions. As a result of
client visibility and input during the development process, the delivery of the
system went very smoothly. The process also helped in the validation and
verification of the model. Immediately, the client realized that the model provided
tremendous insight and enhanced visibility of the freshwater system. This
allowed for greater flexibility in implementing the conservation plan. Particularly,
the plan can now be implemented at sub-system level if desired. The potential is
that conservation goals can be simulated, implemented, and met with minimal
impact to the community. “What if’ scenario simulation will allow for constant
assessment of ongoing conservation measures and facilitate in decision triggers
to adjust the conservation phase. In addition to meeting the proposed problem,
the client quickly realized that the model was versatile enough for use in related
areas.
EXTENSION OF MODEL USE
Like all military facilities, West Point is always conscious of security and
protecting the men, women, and families who work and reside at the Academy.
The Directorate of Housing and Public Works quickly realized that the model had
the potential to simulate catastrophic “what-if” scenarios that could pose a threat
to the community. The model allows for taking resources off-line and simulating
the recovery of the system. This ability in the model has allowed for significant
analysis of system recovery, mitigating the risk of future disruption of the
Academy's mission and the potential threat the human well-being.
CONCLUSION
This was the first time that Systems Dynamics was used during a
capstone experience in the Department of Systems Engineering at the United
States Military Academy. The effort proved tremendously successful from all
perspectives, client, faculty, and cadet. In addition to providing an outstanding
product to the client that benefits the community, the capstone experience
reinforced the value of Systems Dynamics in the analysis of complex, real-world
problems.
REFERENCES
Farr, John V., Lee, Marc A., Metro, Richard, Sutton, J ames. Using a Systematic
Engineering Design Process to Conduct Undergraduate Engineering
Management Capstone Projects, American J ournal of Engineering Education,
April 2001.
Spears, Matthew, Misenheimer, J ohn G. Lee, Marc A. USMA Fresh Water
Decision Support System, Proceedings of the University of Virginia's Capstone
Conference, April 2000.
Sterman, J ohn D. Business Dynamics: Systems Thinking and Modeling fora
Complex World, Boston: Irwin, McGraw-Hill, 2000.
