Research & Innovation

Wet Pond Maintenance for Phosphorus Retention

Summary:

Rainwater washing over streets and other areas picks up pollutants that are harmful to water quality. Thousands of stormwater retentions ponds, including some in parks and other community settings, are designed to trap these pollutants in sediment to prevent them from overflowing into lakes and streams. New research gives cities and counties cost-effective methods to ensure the ponds continue to operate as intended. After high concentrations and releases of phosphorus—the culprit of toxic algae blooms—were found in some older or failing ponds, the Local Road Research Board worked with researchers to mitigate sediment phosphorus release. Dredging and disposing of contaminated sediment, which is the traditional response, can be too costly and logistically challenging. Using modeling, field measurements and data analysis, researchers discovered that treating the sediment with alum or iron filings, installing air diffusers for mechanical aeration, or sometimes using both practices are successful, cost-effective methods for preventing the release of excess phosphorus into Minnesota’s waterways.

Final Deliverables:

• Wet Pond Maintenance for Phosphorus Retention (Report #2022-20)
• Pond Maintenance Strategies to Retain Phosphorus (Research Summary)

Related Materials:

• Are Your Ponds Serving Their Water Quality Function?  (Video/Webinar)

Related Research:

Project Personnel:

Principal Investigator:  John Gulliver
Co-Principal Investigator:  William Herb, Poornima Natarajan, Heinz Stefan, Jacques Finlay, Ben Janke
Technical Liaison:  Leslie Stovring, Patrick Sejkora
Project Coordinator:  Leif Halverson
Panel Members: 
    Beth Neuendorf - Metro District
    Claire Bleser - Riley Purgatory Bluff Creek WD
    Dan Edgerton - Stantec
    Joe Bischoff - Barr Engineering Company
    Randy Neprash - Consultant
    Ross Bintner - City of Edina
    Terry Jeffery - Riley Purgatory Bluff Creek Watershed District
    Tina Carstens - Ramsey Washing Metro WD
    Tom Wesolowski - City of Shoreview