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Overcoming Aged-Infrastructure and Mountainous Terrain –
All-Pipe Modeling for Scranton, PA
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The Challenge:
The Scranton system serves roughly 180,000 people in Northeastern Pennsylvania. The summertime
peak day production in 2006 was 21.5 MGD. Much of the distribution system consists of unlined cast iron pipes.
There are 733 mi of pipes in the distribution system. The distinguishing feature of this system is the steep
terrain which results in a very large number of pressure zones for a system of this size. Since the source is
at a high elevation relative to the majority of customers, most of the flow is by gravity through PRVs.
There are 40 PRV stations, 26 pump stations, 8 wells and 17 storage tanks serving 48 pressure zones. The size
of the pressure zones varies widely. Some may serve only a handful of customers while the largest zone serves
about a quarter of the customers.
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The Solution:
As project manager/consultant for the modeling project, IDModeling expanded Pennsylvania American Water's existing model
of approximately 2000 pipes to an all-pipe model of over 17,000 pipes using Bentley Systems WaterGEMS water distribution modeling solution.
To obtain a more precise loading, PAWC geocoded all of the water meters in the Scranton system and these meters were assigned to nodes in the
model based on Thiessen polygons drawn around each demand node. The demand allocation was much improved using this process.
Once constructed, the IDModeling team used GIS and CAD tools to calibrate the new model and conducted steady-state and extended
period simulation (EPS) analysis scenarios. A great deal of the model calibration work initially involved correctly identifying the extents and
boundaries of the 48 pressure zones and routines such as using network tracing and symbology were developed to assist in the process.
The model was successfully calibrated for EPS conditions and water age analysis was performed on all of the nodes that held a demand.
As a result the model meets EPA and State of Pennsylvania requirements as being an IDSE-compliant model and provides the Pennsylvania American
Water company the framework to better manage its resources and more efficiently plan growth. Pennsylvania American Water provides water and wastewater
services to over two million residential and commercial customers in 35 Pennsylvania counties.
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# # #
IDModeling is a specialty service company, uniquely qualified to deliver
hydraulic modeling solutions for both water/wastewater utilities and
engineering consulting firms. IDModeling focuses on hydraulic model
construction, development, calibration, analyses, and software or
system-specific training as stand-alone services or within the context
of master planning and operational studies. Bringing a customer-first
approach to projects, IDModeling has seen international receptiveness
and works with utilities and consultants to help satisfy SBE, MBE, and
DBE certifications. IDModeling can be reached at the contact
information below and may be visited at
www.idmodeling.com
Contact
Mr. Rajan Ray
rajanray@idmodeling.com
(401) 787-2040
Training Contact
training@idmodeling.com
Employment Contact
careers@idmodeling.com
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