The city of Boston recently completed a new 508-square-foot “porous alley” that absorbs stormwater and filters it into the ground, rather than allowing it to make its way into the sewer system where it has to be treated.
Construction of the alley is part of a larger effort to boost the quality of water in the rivers surrounding Boston. Like many other localities, the Boston Water and Sewer Commission had to pay a fine for violating the Clean Water Act and take steps to minimize pollutants going into the waters. The porous surfaces also help keep ground water at optimal levels in neighborhoods such as the South End, where many buildings were constructed on top of wood pilings, which can rot if exposed to open air.
The nearby town of Arlington, Massachusetts, also used porous pavement for a project on Hurd Field to protect the water quality of adjacent Mill Brook.