The Boston Water and Sewer Commission received a $235,000 federal fine in August for Clean Water Act violations in discharging sewage- and stormwater-related pollutants into Boston Harbor. But as part of a consent decree with the U.S. Environmental Protection Agency, it also agreed to take proactive steps by implementing green stormwater infrastructure and low-impact development projects.
The commission is working with the city to build three green demonstration projects in Boston, says the agency's chief engineer, John Sullivan. "Lessons learned will be used to help develop our future deployment strategies for green infrastructure in the city."
The $3.5-million Central Square East Boston project, with design by Howard/Stein-Hudson Associates now 75% complete, will use three types of stormwater infiltration trenches, says Tony Omobono, vice president of CH2M Hill, a green infrastructure consultant to the city. The trenches include sand-based bedding below open-joint structural pavers that allow for infiltration through joints; washed aggregate trenches below pervious and impervious asphalt pavement, and another application of the washed aggregate trenches below porous concrete.
The project is set for bid by spring 2013. Green infrastructure will include monitoring wells and control structures to check inflow and outflow, Omobono says. "This is unique for the city because the applications can monitor quality and quantity of runoff being treated."
In Onondaga County, N.Y., CH2M Hill is lead designer for an $87-million green infrastructure program set for construction completion by 2018.
Green infrastructure applications also will be used for the $5.5-million Audubon Circle project, still in early design with construction set for 2014. Jerry Friedman, a project design manager for HDR, says biofiltration planters, porous pavement and structural planting soils may be used to promote street tree growth. City Hall Plaza, the third mandated project, will involve green upgrades by the Massachusetts Bay Transportation Authority as part of a $62-million station project, says Andrew Brennan, director of environmental affairs. HDR is designing a system, set to be bid next month, to capture stormwater through permeable pavers into tree pits to soak up volume, Sullivan says. Filtration through loam and sand using underdrains will avoid water infiltration to tunnels and utilities below.