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Computer modeling helps Pueblo Water see the future

August 24, 2020

In her office on the third floor of the Alan Hamel Administration building in downtown Pueblo, Emily Logan stares into a crystal ball and attempts to see the future for Pueblo Water’s customers.

Her crystal ball is really a computer. And she uses the latest available modeling software, not mystic spells, to conjure up images of predictable snowfall, lake and river configurations, the effects of climate change and many other variables to forecast the water needs of Puebloans now and 50 years from now.

Based on historic performances thus far, Logan’s predictions hold water.


Logan is a water resource engineer at Pueblo Water. She employs a modeling system called RiverWare® to aid in long-term planning. Developed by the Center for Advanced Decision Support for Water and Environmental Systems (CADSWES) at the University of Colorado in Boulder, RiverWareis a river system modeling tool for operational decision making, responsible forecasting, and long-term planning. It creates a network of simulation objects to form a river or reservoir network (these objects can either be reservoirs, river reaches, confluence, diversion, etc.). Each object then has governing equations that propagates values via the links that connect the network. Pueblo Water’s model was created by Precision Water Resources Engineering. They developed code to model Pueblo Water’s operations utilizing the RiverWare software.

“Since we can’t predict the future, it’s important to understand how climate change is expected to impact hydrology, as well as demand to make sure the model is telling us something relevant,” Logan said. “So, while the model is accurate historically, we can never be sure if our assumptions about the future are correct. The best we can do is use the science we have to make the best predictions we can.”

Logan explains the modeling technology like this:

“For example, a reservoir is going to solve by mass balance; a river reach will solve by routing, diversion and return flow calculations. These are called the physical processes that govern each object. However, rather than just having specified input values, rules provide a means for simulation driven by logical policy statements (essentially the way the Arkansas River is operated – Pueblo Water’s operations as well as other major entities are coded into the model).

“When doing a run, I would determine the appropriate hydrology to use, pick the appropriate demands, and then a time frame. RiverWare will then determine our imports from the hydrology specified and it would run via the operational rules and physical processes discussed above. Since RiverWare is dynamic, it’s easy to change a lot of the parameters (i.e. reservoir storage quantity or demands) to do a lot of ‘what-if’ scenarios.”

That is rule-based simulation. In addition to that aspect, RiverWare also accounts for our water rights. The software can model Colorado’s prior appropriation system. RiverWare tracks ownership and water type through each of the network of objects.

Logan said that with climate change and a growing population, every utility needs to model the future and ensure it is providing a reliable supply to its customers. The program also is used to aid in decisions related to our leases and reservoir expansions.

Emily Logan is a Water Resources Engineer focusing on efficient management of Pueblo Water’s water rights to ensure a reliable supply in the future. With more than four years of experience in both the public and private sector, she has performed hydrologic and hydraulic modeling, floodplain analyses, environmental investigations, and prepared drainage reports. Emily has brought innovative ideas to streamline processes for both government organizations and clients, including app and database development. Emily holds a bachelor’s degree in Statistics from the University of Chicago as well as a master’s in Environmental Engineering from Northwestern University. She is an active member in AWWA, ASFPM and Engineers Without Borders.

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