Happy New Year...

...from all of us at the Stormwater Research group of St. Anthony Falls Laboratory, University of Minnesota!!! We wish you all the best during this holiday season and that 2026 is fruitful and fulfilling.

Stormwater Reduction and Pollutant Sourcing from Urban Trees

Please join us in person or online on January 15, 2026 at 10am (US central time) for the next Minnesota Stormwater Seminar Series event - a monthly experience featuring national, state, and local experts on stormwater and green infrastructure.

Speakers & Panelists:

• Co-Presenter: Xue Feng, Associate Professor, University of Minnesota, Department of Civil, Environmental, and Geo- Engineering, Saint Anthony Falls Laboratory
• Co-Presenter: Diana Karwan, Associate Professor, University of Minnesota, Department of Forest Resources
• Panelist: Dustin Ellis, Forestry Supervisor, Hennepin County
• Panelist: Mirae Guenther, Water Resources Data Analyst, Mississippi Watershed Management Organization

Abstract: Trees are ubiquitous in urban environments and are appreciated for a range of ecosystem services. However, the tradeoff in their ability to reduce stormwater runoff volumes versus their potential contributions of nutrient and coarse organic matter in dissolved and particulate forms has been largely ignored in stormwater management practices due to lack of robust data. Our project has now filled some of these data gaps through a three-year monitoring effort to quantify tree-scale water quantity and quality fluxes across eighteen ash (Fraxinus spp.) trees and four maple (Acer spp.) trees in the city of St. Paul.

We also examine how these local measurements and seasonal patterns relate to corresponding watershed-level stormwater observations. Our results revealed that throughfall nutrient fluxes were higher under trees than in open precipitation, despite an overall reduction in water volumes due to canopy interception. Nevertheless, these nutrient contributions can potentially be mitigated through improved tree health, which also increases soil water uptake through enhanced evapotranspiration. Finally, leaf litter nutrient content progressively declined closer to the pavement curb, suggesting that trees near and overhanging impervious road surfaces can contribute throughfall nutrient fluxes that quickly enter the stormwater network.

DATE & TIME: Thursday, January 15, 2026, 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. The seminar is supported in kind by the Cold Climate Stormwater Center of Excellence, which is funded by the U.S. Environmental Protection Agency and co-directed by the University of New Hampshire and the University of Minnesota, in partnership with the National Municipal Stormwater Alliance. 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 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):

• Addressing the challenge of water-soluble emerging contaminants in green stormwater infrastructure featuring Greg LeFevre, University of Iowa, and local experts.
• Urban Flash Flood Detection with Low-Cost IoT Sensor Networks featuring Bill Selbig, USGS, and local experts.
• 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

Exploring Iron Enhanced Sand Filters

Join us for an interactive workshop to explore the design and maintenance of iron-enhanced sand filters for stormwater treatment. You'll hear from researchers, practitioners, and engineers about recent advancements in iron-enhanced sand filter design, lessons learned in their construction, and ideas for overcoming challenges to maintaining them. This workshop is presented by UMN’s Water Resources Center, Freshwater, and the Rice Creek Watershed District.

DATE & TIME: Friday January 16, 2026, 9:30am - 3:00pm US Central

In-person:  Court International Building, 2550 University Avenue W, Suite 320N, St. Paul, MN

Registration& More Info: Click here to Register or Click here for a PDF Flyer.