Please join us NEXT WEEK in person or online on September 11, 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. 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, and made possible through the Minnesota Stormwater Research and Technology Transfer Program in collaboration with the Minnesota Stormwater Research Council.

Performance and Maintenance of Sand Filters Amended to Retain Phosphate

Speakers & Panelists:

• Presenter: John Gulliver, Professor Emeritus, Civil, Environmental and Geo- engineering and St. Anthony Falls Laboratory
• Panelist: Tim Olsen, Bolton & Menk
• Panelist: Bridget Osborn, HR Green
• Panelist: Chris Kucek, Capitol Region Watershed District
• Panelist: Ryan Johnson, City of Roseville

Abstract: The iron enhanced sand filter (IESF) is a popular stormwater control measure in Minnesota, employed to reduce phosphorus inputs to water bodies from urban storm runoff. Although IESFs have been employed for over a decade, research and development of technology remains limited. There is a large amount of anecdotal information from practitioners but often this leads to more questions than answers. The Minnesota Stormwater Research Council funded a project to combine the observations and experiences of IESF operators with field monitoring and chemical analysis to expand our fundamental understanding of the relationships between design, maintenance, performance and lifespan of IESFs. We collected water quality data and analyzed media samples from 24 different IESFs throughout the Twin Cities Metro Area. We developed an empirical method for estimating total phosphorus (TP) retention over time and investigated the correlation between TP retention and depth of water treated by the IESF. We also investigated the correlations between soluble reactive phosphorus (SRP), the depth of water treated, the total phosphorus to total iron ratio of the IESF media, and the capacity remaining as determined by batch tests. Our results demonstrate the usefulness of some straight-forward measurable IESF parameters in understanding the performance of an IESF over its lifespan. Coupled with information gathered from the IESF operators who participated in this study, we have expanded the guidelines for proper maintenance to maximize the performance and lifespan of an IESF.

DATE & TIME: Thursday, September 11, 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.

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Previous Seminars (YouTube Channel):

• Managing Stormwater Ponds for Optimal Function: Characterizing Phosphorus and HAB Export, Plus a New Tool for Prioritizing Maintenance Needs featuring Presenter: 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
• Does it age like a fine wine or are we having a midlife crisis? Evaluating older bioretention system performance and soil evolution featuring Ryan Winston, Ohio State University and local experts.
• Bioretention: Where soil, plants and rainwater have a rootin’ good time! featuring Shirley Clark, Penn State Harrisburg and local experts.
• Trees, Ponds, and Watersheds: Long-Term Ecological Research to Understand People and Water in Cities featuring faculty from the MSP Urban LTER.
• Plants for Stormwater Design, Interactive Selection Tool for Stormwater Professionals and the Public featuring John Bly (Metro Blooms) and Dan Shaw (BWSR), and local experts.
• Rethinking Green Stormwater Infrastructure in Place featuring Ashlynn S. Stillwell, University of Illinois Urbana-Champaign, and local experts.
• Performance of Stormwater Products and Practices: Why it Matters featuring Seth Brown, NMSA, and local experts.
• Capturing and quantifying coarse organic matter in urban stormwater featuring John Chapman, Univ. of Minnesota and local experts.
• Defining the footprint of sediment in green stormwater infrastructure featuring Virginia Smith, Villanova University, and local experts.
• Harnessing Minnesota's Stormwater Data for Improved Modeling and Management of Water Quality in Cities featuring Jacques Finlay & Ben Janke, with local experts.
• Leveraging Grant Funds for Stormwater & Community Resilience Planning featuring Linnea Savereide, Paula Kalinosky, Ian Weber, Trent Imdieke, Troy Erickson, Camilla Correll, Andrea Crabtree Nayes, Mike Love.
• Ushering in a new era of TMDL compliance: Adaptive management and reducing connected impervious cover. Jamie Houle, University of New Hampshire, and local experts.
• Retrofitting existing SCMs to enter the nutrient trading market. Bill Hunt, North Carolina State University and local experts.
• Filtration media expert panel discussion featuring Erin Anderson Wenz, Mei Cai, Erik Megow, Mike Isensee, Bridget Ulrich, Andy Erickson, and Joanne Boettcher.
• Biofiltration Media – Phosphate release or capture, plant growth, chloride impacts, and more! Andy Erickson, St. Anthony Falls Lab, U of M Twin Cities.
• Biochar for stormwater management: Challenges in translating success from the laboratory to the field. Bridget Ulrich, NRRI & UM-Duluth.
• Road salt impacts: Stormwater, surface water, groundwater, ecosystems and drinking water supplies. Joel Moore, Towson University with local experts.
• Infiltration as a stormwater management practice. John Gulliver; Todd Shoemaker; Noah Czech; Mike Gerber; Forrest Kelley; Eric Lund; John Nieber; and Mike Trojan.
• Street Sweeping for Water Quality: A Panel Discussion, Sarah Hobbie, Mike Trojan, Mike Kinney, and Paula Kalinosky.
• Assessing ecological impacts from urban stormwater to rivers, streams and estuaries. Ken Schiff, Southern California Coastal Water Research Project with local experts.
• Stormwater reuse and human health: A panel discussion. Nancy Rice (MN Dept. of Health); Anita Anderson (MN Dept. of Health); Tamara Walsky (University of Minnesota); Satoshi Ishii (University of Minnesota); Sybil Sharvelle (Colorado State University).
• Prioritizing chemicals and chemical mixtures of ecological concern in Great Lakes tributaries. Steven Corsi, Research Hydrologist, U.S. Geological Survey, Madison, WI, with local experts.
• Real time monitoring and control of green infrastructure for improved stormwater management. David McCarthy, Monash Infrastructure Institute, Department of Civil Engineering, with local experts.
• Stormwater Research Spotlight: "A simulated examination of stormwater sampling methods." Daniel Furuta and Bruce Wilson, Bioproducts and Biosystems Engineering, University of MN.
• Co-Design Sustainable, Resilient, and Just Nature-based Stormwater Solutions with Communities. Chingwen Cheng, Landscape Architecture, Urban Design, and Environmental Design, Arizona State University, with local experts.
• Stormwater Research Spotlight: "Equipping Municipalities with Climate Change Data to Inform Stormwater Management." Ryan Noe, Humphrey School of Public Affairs, UMN.
• Advancing Green Infrastructure Practices through CLASIC Life Cycle Cost and Triple Bottom Line Benefit Analysis. Harry Zhang, The Water Research Foundation (WRF), with local experts.
• Stormwater Research Spotlight: Evaluation of Microbial and Chemical Contaminant Removals in Different Stormwater Reuse Systems (Satoshi Ishii) & Pollutant Removal and Maintenance Evaluation of Underground Sand Filters (Todd Shoemaker)
• The Stormwater Corps: Integrating Undergraduate Student Training into Municipal Stormwater Retrofit Planning. Michael Dietz, University of Connecticut, with local experts.
• Stormwater Research Spotlight: Pond treatment with spent lime to control phosphorus release from sediments. Greg Wilson, Barr Engineering.
• Spatial and Temporal Scaling of Biofilter Media Performance Data and Updates to WinSLAMM. Robert Pitt, University of Alabama, with local experts. 
• Stormwater Research Spotlight: Biofiltration Media Optimization: Phase I Results, Phase II preliminary results, and Future Work. Andy Erickson, St. Anthony Falls Laboratory, University of Minnesota.  
• Underground Stormwater Control Measures. James Lenhart, Stormwater Northwest, with local experts.
• Stormwater Research Spotlight: Identifying Sources of Contaminants in Urban Stormwater and Evaluation of Their Removal Efficacy through Urban Best Management Practices (Heiko L. Schoenfuss, and Richard Kiesling)
• Permeable Pavement Maintenance: Designing to Reduce Maintenance, Planning for Maintenance Frequency, and Effective Techniques to Restore Pavement Hydraulics. Ryan Winston, The Ohio State University with local experts.
• Stormwater Research Spotlight: Inspiring Community Action for Stormwater Management (Sarah Roth and Amit Pradhananga).
• Green Infrastructure Strategies for Creating Sustainable Landscapes: Bioswales/’Scoop and Dump’/ CU-Soil. Nina Bassuk, Cornell University with local experts.
• Stormwater Research Spotlight: Detecting phosphorus release from stormwater ponds to guide management and design. (John Gulliver & Jacques Finlay; UMN) & Pond Treatment with Spent Lime to Control Phosphorus Release from Sediments (Greg Wilson)
• Research on Green Infrastructure at the USEPA. Michelle Simon, US EPA with local experts.
• Stormwater Research Spotlight: Pollutant Removal and Maintenance Assessment of Underground Filtration Systems (Phase I) (Todd Shoemaker & Ali Stone, Wenck) & Temporal Dynamics of Pathogens and Antibiotic Resistance Genes in Raw and Treated Stormwater (Satoshi Ishii, UMN)
• Designing of the Next Generation of Sustainable Urban Stormwater Practices. Tom Schueler and David Wood, Chesapeake Stormwater Network with local experts.
• Stormwater Research Spotlight: Characterization of Stormwater Particle Size Distribution and Sediment Concentration through Evaluation of Manhole Sumps with SHSAM (John Chapman) & Developing a street sweeping credit for stormwater phosphorus source reduction (Sarah Hobbie and Mike Trojan).
• Research to Practice: Lessons in Resilience from Monitoring Urban Stormwater Transportation Systems. Rob Traver, Villanova University with local experts.
• Stormwater Research Spotlight: From Policy to Action: Community Driven Stormwater Management (Mae Davenport) & Establishing a Geodata Standard for Stormwater Infrastructure (Geoffrey Maas).
• Pathogens in Urban Stormwater Systems: Tools for the Municipal Stormwater Manager. Jane Clary, Wright Water Engineers, Inc., with local experts.
• Bioretention Soil Media, Vegetation, and Maintenance: Lessons learned from Green Stormwater Infrastructure research in Vermont. Stephanie Hurley, University of Vermont with local experts.
• National Topics in Stormwater Relevant to Local MS4 Program Managers. Seth Brown, National Municipal Stormwater Alliance and Storm and Stream Solutions, LLC with local experts.
• Bioretention and Treatment Media: A Phosphorus Story. Allen Davis, University of Maryland with local experts.
• Tree function in stormwater biofilters: the green in green infrastructure. Jon Hathaway, University of Tennessee, Knoxville with local experts.
• What happens when permeable pavements freeze? Jenn Drake, University of Toronto, with local experts.
• Optimization Modeling: Can We Plan our Infrastructure More Efficiently? Using Renfrew, Calgary, as a Case Study. Scott Struck, Geosyntec Consultants, with local experts.
• Modernizing Performance Metrics for Stormwater Infrastructure. Elizabeth Fassman-Beck, Stevens Institute of Technology with local experts.
• Innovation and Technology Evolution in Water Resources Engineering: Where are we headed and how will we get there? Marcus Quigley, EcoLucid, with local experts.
• Moving from an industry of the problem to an industry of the solution: linking scientific research to decision-making and adoption approaches. Jamie Houle, University of New Hampshire Stormwater Center with local experts.
• Investigating the Stormwater Quantity and Quality Impacts of Urban Trees. Bill Selbig, USGS Wisconsin Water Science Center with local experts.
• A New Dynamic Horizon in Stormwater. Bridget Wadzuk, Villanova University with local experts.
• It Rained Two Feet, Now What? Bill Hunt, North Carolina State University with local experts.