Project overview
Reducing phosphorus (P) release from ponds that treat stormwater is a major stormwater management challenge because phosphorus is the primary limiting nutrient. Reducing P availability is necessary to prevent algal blooms and reduce or eliminate floating plants like duckweed and watermeal. Many ponds are also seen as an amenity, such that reducing algal blooms and floating plants in the ponds is an additional challenge. Sediment P release in ponds that treat stormwater reduces the overall effectiveness of the pond in capturing and retaining phosphorus, a primary function of the pond.
The goal of this research project is to determine the effectiveness of the four most promising approaches for improving P removal in ponds: application of alum or iron to reduce P release from the sediments, and street sweeping to reduce inflowing organic material which contains labile organic P. The research team will also develop maintenance guidelines for these treatment technologies that considers cost-effectiveness for P reduction over time.
Research questions
- How long and under what conditions will alum treatments reduce sediment phosphate release in the highly organic pond environment with high depositional rates?
- How long and under what conditions will iron filing treatments reduce sediment phosphate release in the highly organic pond environment with high depositional rates?
- Can artificial aeration be a successful and cost-effective pond remediation technique for controlling internal P loading?
- To what extent can intensive street sweeping reduce sediment phosphate release and total P concentrations in ponds that treat stormwater?
Key innovation/contributions
The results of this research will contribute to the development of recommendations for remediation techniques that can reduce phosphorus concentrations in stormwater ponds.
What does this mean for Minnesota?
We are studying pond remediation of phosphorus export because we want to find out which remediation technique is the most cost-effective in order to understand how to remediate phosphorus export for different types of ponds so that we can continue to clean up our lakes and streams and might be able to delay expensive dredging for a few years.
Reports and Presentations
- Project update 2024 .pdf