The Walsh administration brought its program of environmental action and climate-change preparedness to the South End with the repaving of Public Alley 543, between Holyoke and West Canton Streets, with porous asphalt. The new "porous alley", which will aid water filtration and help mitigate internal flooding, was celebrated with a ribbon-cutting by Mayor Walsh on Friday morning, November 21. The mayor was joined by officials from the Massachusetts Department of Environmental Protection (DEP), Boston Public Works Department (BPWD), Boston Groundwater Trust and the Charles River Watershed Association (CRWA). Citing the need for the environmental upgrade, Mayor Walsh said, "Storm-water pollution and groundwater do not understand our municipal or property boundaries, and we must work together to address these challenges. I applaud the Charles River Watershed Association for their vision, the DEP for helping fund this work, and the City's Department of Public Works for implementing the new porous alley."  Public alley 543 is Boston's second porous alley, the first being public alley 444, which runs between the Boston Architectural College's buildings at 951 Boylston Street and 320 Newbury Street. Public Alley 543 was chosen as a site because it has low groundwater levels, and it has a nearby storm drain connection which facilitates monitoring of runoff and water quality.

Julie Wood, director of projects for CRWA offered explanatory remarks and fielded questions while Elizabeth Cianciola, an aquatic scientist with CRWA, checked groundwater levels and took samples from a well. Katie Choe, chief engineer of the BPWD, explained the process of retrofitting the alley with the new, porous paving. "The piece that the neighbors clearly know a lot about is that it is very disruptive because a lot of work goes into it. We had to dig a very deep pit, which we don't normally have to do, and there was a lot of utility relocation involved." Choe continued that once the pit was lined, two layers of stone totaling six inches were laid below the asphalt to support the heavy traffic, including trash trucks, that traverses the alley. Maintaining an adequate groundwater level is particularly vital to the South End, which is largely filled in and built on pilings that must remain moist with groundwater in order to prevent rotting due to microbes.

Elsewhere in the city, different, other new approaches are underway to monitor and protect water quality in the city's natural areas. Bill King, a retired biomedical researcher and a member of Brighton's Chandler Pond Preservation Society who is being trained by CRWA in water quality surveying, rode his bicycle from Brighton to the porous alley dedication. Commenting on the significance of the porous asphalt, King said, "Storm water runoff is an issue, and there is a cost increase because it has to be processed. Originally, storm water was connected to the sewage system, and the street runoff would be processed with sewage, and there would be overflows of sewage into the ocean. Now they are restricting storm water runoff and this is part of that," King said. CRWA is training King as a volunteer in macro-invertebrate sampling, which involves taking water samples from lakes, streams and ponds and testing for the presence of various species of insect larvae that are more sensitive or more resistant to water pollutants. King is learning to preserve and classify the samples, then send them off for double-checking by professionals. "It's a standard test that the EPA controls. If certain species like mayflies can live in the water, it shows that it is not too polluted. If there are mosquito larvae, which are more resistant to pollution, then the water is probably polluted. It's a cheap way of surveying, and the chemistry test doesn't test for everything, anyway," King observed. The objective is to have volunteers supplement professional surveyors so that more sites can be tested. Both the porous alley project and the macro-invertebrate sampling program are part of CRWA's Blue Cities Initiative, which operates in Boston, Brookline, Newton and other Charles River watershed communities.

Further information on the porous alley project is available at http://www.crwa.org/blue-cities/demonstration-projects/porous-alley.