The Minnehaha Creek Watershed District (MCWD) is beginning dredging work on two stormwater ponds that clean polluted stormwater that runs off city streets in Minneapolis and Edina.
The Southwest Bde Maka Ska Pond in Minneapolis filters runoff before it enters Bde Maka Ska (formerly known as Lake Calhoun) and the Pamela Park Pond Cell 1 in Edina filters runoff before it enters Minnehaha Creek.
Dredging involves excavating the sediment out of the ponds and hauling it away. Any disturbed vegetation will be restored in the spring.
About 2,000 cubic yards of sediment will be removed from Southwest Bde Maka Ska Pond, which was last dredged in 2012. At that time, the dredged sediment that was removed was near contamination, but current tests indicate the sediment is not contaminated this time around.
About 1,900 cubic yards of sediment will be removed from the Pamela Park Pond Cell 1 and will be the first dredging of this pond. The project is being conducted in partnership with the City of Edina.
Dredging is done during the cold weather months when the ground is frozen. The ponds will be “dewatered,” meaning the water will be pumped out of them and stored in an adjacent pond. The stormwater ponds will then be excavated using heavy machinery. The sediment from the ponds will be hauled offsite.
The work is expected to last through February.