Project Summary:

This project provided the first fundamental understanding of the two-phase flow physics that trigger geysering in storm sewer systems. It introduced two passive retrofitting methods for dropshafts that successfully prevented geysers by enabling smooth air release without surface water spill, thereby avoiding the pressure conditions that initiate geysering.

A reduced-order geyser prediction module was developed and integrated into open-source software for modeling storm sewer flow dynamics. This tool is now available to assist engineers in the design and retrofitting of sewer infrastructure. The project also expanded the application of DPIV (Digital Particle Image Velocimetry) to new engineering contexts and generated valuable experimental data for validating numerical models and retrofit strategies.

Violent geysers in stormwater and combined sewer systems were found to result from rapid gas-liquid eruptions in dropshafts, reaching heights of several tens of meters. Triggered by air entrapment during intense rainfall, these events caused significant damage and forced utilities to operate systems below capacity—leading to more frequent sewer overflows.

This project provided the first in-depth understanding of geyser mechanisms through laboratory experiments, high-speed imaging, DPIV, and 3D CFD modeling. The team also tested passive retrofitting methods that allowed safe air release without triggering eruptions.

The results support improved design and retrofitting of stormsewer systems. The project also developed hands-on educational modules on sewer overflows, delivered to underrepresented middle school students through an existing outreach program.

Previous Work:

Dr. Arturo Leon’s team was the first to replicate violent geysers in a laboratory setting, capturing real-world-like eruptions. A video of the experiment is available here.

Validated 3D simulations using OpenFOAM were developed and used to test various retrofit strategies, now available for application in stormsewer infrastructure projects.