383 - Proxy Methods for Quantifying Geyser Potential in Stormwater Networks

Water geysers erupting from manholes pose a significant risk to surrounding urban environment, human health and safety during intense storm events. Predicting water geysers in stormwater systems is challenging due to their genesis in multiphase flows, which are neglected in standard stormwater network models such as the Storm Water Management Model (SWMM). Previous research on geysers has mainly centered around multiphase interactions occurring within individual conduits or limited sections of networks, employing experimental or computational methodologies that are not amenable to conducting comprehensive analyses on large systems. Consequently, effectively addressing this challenge calls for a transition towards more comprehensive network approaches. We propose a new analysis method to bridge the gap between detailed representation of geysers in stormwater networks and practical modeling constraints. Using output from SWMM, the new approach quantifies surge intensity across network segments as a proxy for the potential of air entrapment and pressurization–phenomena that are precursors for "adverse multiphase flow interactions" (AMFI), including geysers. To demonstrate the utility of the new method, it is applied across a variety of networks, including individual conduits, dendritic and looped networks, and major portions of an anonymized city system. Presently, comprehensive evaluation of the new method is complicated by the limited availability of real-world geyser data and information on the system conditions preceding them. Thus, this work is a building block towards more comprehensive large-scale modeling of stormwater geysers, which remains an important unmet need in urban stormwater management.