Performance and Maintenance of Sand Filters Amended to Retain Phosphate

Do you have a phosphorus TMDL and you're looking for something to remove phosphate from stormwater? Roughly 200 iron enhanced sand filters (IESFs) have been installed in Minnesota alone to do just that. Questions, like what is a reasonable lifetime of the IESF media, what maintenance and maintenance frequency is required, and is the spent media toxic were all uninvestigated. The Minnesota Stormwater Research Council funded a project at the St. Anthony Falls Laboratory, University of Minnesota, to investigate these unknowns surrounding IESFs.

Please join us in person or online on November 20, 2025 at 10am (US central time) for the next Minnesota Stormwater Seminar Series events - a monthly experience featuring national, state, and local experts on stormwater and green infrastructure.

Low-cost sensor networks for pluvial flash flood detection and early warning in urban areas

Speakers & Panelists:

• Keynote Presenter: William Selbig, Research Hydrologist; USGS Upper Midwest Water Science Center
• Panelists: TBD

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.

DATE & TIME: Thursday, November 20, 2025, 10a - 12p US Central

In-person: St. Anthony Falls Laboratory Auditorium (2 Third Ave SE, Minneapolis, MN)

Online: https://z.umn.edu/mn-stormwater-seminar-series (active 10 minutes prior)

Registration: Click here to Register

About the MN Stormwater Seminar Series:

The Minnesota Stormwater Seminar Series is a monthly experience featuring national, state, and local experts on stormwater and green infrastructure. This seminar series is a partnership between the University of Minnesota's St. Anthony Falls Laboratory and Water Resources Center, and the Minnesota Pollution Control Agency. This seminar comprises national experts on advanced stormwater innovation and knowledge sharing what they've learned; experts and researchers from Minnesota who have recently completed or are working on innovative and high priority stormwater research; and national, state, and local experts sharing their practical experiences on the state-of-the-science topics that are important to Minnesota practitioners. The Series is made possible by the Minnesota Stormwater Research and Technology Transfer Program in collaboration with the Minnesota Stormwater Research Council and supported through an appropriation from the Clean Water Fund established by Minnesota Clean Water Land and Legacy Amendment.

See the full schedule here or visit our YouTube Channel for all recordings.

Recent Seminars (YouTube Channel):

• Enhanced Street Sweeping: America's First Line of Defense in the Abatement of Urban Stormwater Pollution featuring Roger Sutherland, Cascade Water Resources, LLC, and local experts.
• Performance and Maintenance of Sand Filters Amended to Retain Phosphate featuring John S. Gulliver, St. Anthony Falls Lab & University of MN, and local experts.
• Managing Stormwater Ponds for Optimal Function: Characterizing Phosphorus and HAB Export, Plus a New Tool for Prioritizing Maintenance Needs featuring Katie Hembre (Stantec), Dr. Poornima Natarajan (UMN SAFL), and local experts.
• Using Winter Chloride Management to Reduce Impacts of Winter Maintenance Operations featuring Laura Fay, Montana State University, and local experts.
• Turning tight spaces into big solutions: testing a high-volume stormwater filter at Rosland Park featuring Andy McCabe, Barr Engineering, Erica Sniegowski, Nine Mile Creek Watershed District, and local experts.
• Extreme Weather Impacts Across the Water Sector Sunny Wescott, Cybersecurity and Infrastructure Security Agency (CISA) Chief Meteorologist and Federal Emergency Response Official and local experts.
• Assessment of urban stormwater chloride and its impact on surface water trends featuring Dr. Ben Janke, Dr. Jacques Finlay, and local experts.
• Funding and technical assistance for stormwater management and green infrastructure featuring Robyn DeYoung, US EPA; Travis Ostrom, US EPA, and local experts.
• Moving towards multi-functional stormwater management systems featuring Lauren McPhillips, Penn State University, and local experts.
• Watershed-scale effectiveness of green stormwater infrastructure featuring Aditi Bhaskar, University of Colorado Boulder, and local experts.
• Emerging policy issues that may influence future stormwater management efforts featuring Chris Kloss, U.S. EPA, and local experts

Stormwater Nutrient Management Webinar – Keeping Water Blue and Landscape Green

Abstract: As we continue to address the impact of stormwater on nutrient loads in New England waterways, practitioners must remain creative and innovative in identifying solutions. This webinar is part of NEWEA’s ongoing effort to bring cutting-edge science and understanding to inform best practices for nutrient management and removal in stormwater. Attending this webinar will provide you with the latest research and practical solutions that can be directly applied to your work, ensuring you stay ahead in the field.

On October 28 NEWEA’s Stormwater Committee will host three thought leaders from across the country to share their insights with us on stormwater-based nutrient control.

Stephanie Hurley from the University of Vermont will share lessons learned from research on designing bioretention and other stormwater treatment practices for nutrient removal. Andy Erickson from the University of Minnesota will discuss the design and performance of iron-enhanced media filtration to capture phosphorus. Finally, Bill Hunt from North Carolina State University will provide insights from his work on the performance of unmaintained Stormwater Control Measures. These topics will provide valuable tools for municipal managers, the consulting community, policymakers, and the environmental community to make effective changes in strategies for protecting and restoring our waterways.

DATE & TIME: Tuesday, October 28, 2025, 11a - 12:30p US Eastern