Prior to construction of the treatment pond in 2007, stormwater traveled south along Seminole Highway to the north side of the Union Pacific Railroad tracks, then east into the UW Arboretum through Greene Prairie. The purpose of this project was to reduce sediment deposition and erosion in Greene Prairie by redirecting water into a new treatment pond before reaching Dunn's Marsh.
The treatment pond provides 7 feet of dead storage and reduces suspended solids by 48%. Overflow is directed into Dunn's Marsh via sheet flow over an emergency spillway.
This was the first completed project of several porposed in the UW Aboretum's Facility Storm Water Management Plan (pdf).
More information can be found at the UW Arboretum website.