ASCE EWRI Congress: SWWM 5+ preview, water hammer workshop, and a lake that time forgot

Youssef Al Fahham Youssef Al Fahham May 23, 2024

4 min read

This week was the kickoff of ASCE’s EWRI Congress in Milwaukee. Wisconsin’s largest city, Milwaukee also happens to be located along the shores of Lake Michigan, the largest freshwater lake located entirely within the United States.

Did you know Milwaukee was built at the confluence of three rivers. We went on a river walk!

Wisconsin has more than 800 miles of shoreline along Lake Superior and Lake Michigan, which makes it easy to overlook the 15,000 other lakes in Wisconsin. One local lake, in particular, holds a bit of historical mystery.

The lake that time forgot

Lake Emily is located in downtown Milwaukee (in “East Town”), but it actually lies underneath Northwestern Mutual’s corporate headquarters. Yes, underneath that massive building, which was built more than 100 years ago, is where Lake Emily was – and still is in some sense. The waters of Lake Emily cover the thousands of wooden pilings (which prevents them from degrading by being exposed to air), but the water is still about 9 feet below the floor of the building. It can be viewed through one of 74 observation holes in the basement, although there are no public tours offered deep down in the basement.

Was it a real lake or just a catchment pond? That’s one of the mysteries, but there are reports that people swam in it and maybe even stocked it with fish. Interestingly, the engineers who designed and built the headquarters back in the early 1900s made sure all rainwater landing on the building roof would be routed to Lake Emily.

From preserving a lake to preserving a legacy: SWMM

In addition to learning about local water history, I attended the US EPA’s pre-conference technical workshop for SWMM stakeholders and partners, “The Next Generation of SWMM: A Workshop for Stakeholders and Partners”. The meeting was called to share a list of exciting updates, to celebrate SWMM’s history, and to learn more about SWMM 5+ and the latest on collaboration with NOAA.

In terms of the historical details shared during the event, nothing stood out as much as the sheer number of times our own Robert Dickinson was mentioned. I recall several presenters and numerous attendees spotlighting Bob as “one of the pioneers of SWMM over his 40+ year career”, a career that has extended from the early days of SWMM 2 in 1978 to the latest release of SWMM 5. What will Bob think of the next release, the highly anticipated SWMM5+, which is currently in beta? Follow Bob on LinkedIn to find out. He’s always posting about SWMM and runs both and publishes a newsletter on LinkedIn called EPASWMM5 Related Software.

At the event, Dr. Ben Hodgens from the Center for Infrastructure Modeling and Management (CIMM) shared a glimpse of the next version of SWMM 5+, with engine enhancements that are designed to fix mass conservation challenges, provide smoother transitions between free surface and surcharge flows, and capture detailed hydraulic features such as hydraulic jumps, bores, and draw-down to supercritical flow. There is a lot to look forward to in that regard. With the announced memorandum of understanding between ASCE and NOAA around climate data access for modeling, we could be looking at more enriched climate data availability and accessibility in the foreseeable future. 

Water hammer analysis with InfoWater Pro

Although stormwater collection and flood modeling, along with wastewater collection modeling were key topics of emphasis at the conference, drinking water distribution modeling was also represented. Autodesk’s Shawn Huang, Brown and Caldwell’s Chris Michalos, and I gave an extensive workshop on water hammer analysis, beginning with textbook theory to the more practical applications for modeling in InfoWater Pro

We were even courteously invited to visit Dr. William Gonwa’s lab at the Milwaukee School of Engineering to participate in a live water hammer demonstration. Below is some of the data collected from the live water hammer experiment, where the pressure was recorded using a high frequency transient pressure data logger. As one might expect, the demonstration closely followed basic water hammer theory, with the experiment yielding extremely high pressures when the downstream control valve was closed instantly. Compare this to the second demonstration (below), where the valve was closed slowly… if only mitigating water hammer in a real-life water network was that simple! 

Adaptive chemical mixing in InfoWater Pro

Continuing with the theme of drinking water networks, Autodesk’s Principal Software Engineer Felipe Hernandez covered the latest advancements in water quality modeling using InfoWater Pro and EPANET Release 2.2. Felipe’s presentation, “Adaptive Chemical Mixing Resolution to Accelerate Water Quality Simulations without Accuracy Loss” focused on the adaptive mixing and release of incoming chemical species in partial groups to produce a non-homogeneous response from junctions – thereby increasing the temporal and spatial resolution of the model.

Felipe demonstrated the response in two test networks, where a slower deterioration of accuracy was observed as the computational timesteps were decreased. In a nutshell, what Felipe accomplished through this presentation was demonstrating that adaptive chemical mixing could in fact allow water quality simulations to run up to three times faster, without sacrificing accuracy.

We all had a great time at our talks and workshops, one of which was at capacity, and look forward to another trip to Milwaukee in the future.

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