William Street Pond is a stormwater collection pond near William and Elmer Streets in Roseville. To improve the pond’s ability to remove sediment and phosphorus from stormwater flowing through it on the way to Lake McCarrons, pond improvements were completed in September 2011:
- contaminated sediment was removed from the pond to restore its full storage capacity
- a new baffle device and pond inlet pipe were installed
- two iron-enhanced sand filtration benches were added to the slopes near the pond outlet
Iron-enhanced sand filtration helps remove excess phosphorus from stormwater flowing through. The benches are flat areas next to the water line about five feet wide and two feet deep. These benches were filled with a mixture of sand and iron filings. When stormwater flows through the sand, dissolved phosphorus pollution chemically bonds to the iron which prevents it from entering Lake McCarrons.