Abstract
Flooding in urban areas is a serious weather-related threat to life and property. Floods from overbanked rivers or ocean storm-surge can cause catastrophic damage to populated areas, but they often develop over hours or days, giving conventional monitoring and warning systems enough time to respond. Alternatively, pluvial floods, often referred to as flash floods, can develop quickly from extreme rainfall events, sometimes leaving just minutes to react. The mounting risk of these pluvial floods became clear in 2025, when the National Weather Service issued a record number of flash flood warnings, the highest in nearly four decades. As more communities experience an increasing frequency of severe rainfall events, urban flash flood detection systems, or “smart utilities”, are becoming ever more important to provide advance warning of impending floods at vulnerable locations.
In 2018, the USGS, in cooperation with Intel Corporation, Isle Utilities, and Intera Incorporated, initiated a review of smart sensor technologies used by utilities across the globe. The resulting devices selected for this study use a hybrid communication system that combines long range wide area network (LoRa) radio technology with Message Queuing Telemetry Transport (MQTT) messaging, both of which are lightweight communication protocols used in many scientific and industrial applications. The internet-of-things (IoT) devices that leverage these technologies are compact, low cost, extremely energy efficient, and can transmit data at high frequencies and over long distances.
The ability to deploy these devices on a city-wide scale can effectively create a sentinel IoT network to help reduce delays in emergency response by providing real-time measurement of water levels in stormwater pipes, streets, or other urban infrastructure. Data are translated into actionable information by integrating into tailored cloud-based web applications that can clearly communicate flood status in real time. For example, when sensor data from the IoT network are populated into a custom GIS dashboard, it can help visualize areas immediately impacted by localized heavy rainfall with maps of flood extents at the neighborhood scale. Integrating these innovative technologies into a cost-effective, scalable monitoring network that improves situational awareness of urban flash flooding in real time can help cities adapt to the increasing potential of pluvial flash floods.
Bill is a research hydrologist at the Upper Midwest Water Science Center of the U.S Geological Survey. For the past 30 years his research has focused on characterization of pollutants in urban runoff, identification of their sources, and evaluation of the techniques and practices designed to treat them. He holds two patents for innovative stormwater sampling technology and is an active part of the research and development community for the USGS Next Generation Water Observing System program.