By Ashley Taylor

A raindrop looking down on Somerville would not see many cushy places to fall.  That’s because about three-quarters of the land in Somerville – 73 percent, according to Somerville’s Office of Sustainability and the Environment – is impermeable to water, making Somerville the most water resistant city in the region.

Instead of being absorbed, rain that falls on these surfaces, mainly pavement and rooftops, drains into the city’s storm water and sewer system, which, as the July flash floods showed, can’t always handle that much water.

Last Monday night, the Parks and Open Space Committee of the Board of Aldermen considered regulations to reduce Somerville’s high percentage of impermeable surfaces. City Planner George Proakis and City Solicitor David Shapiro appeared before the committee and presented both the current regulations on residents paving over their property and suggestions for deterring residents from doing so.

Finding ways to reduce the percentage of impermeable surfaces in the City has been on the Parks and Open Space Committee agenda since June.  Ward Two Alderman Maryann Heuston, one of the three aldermen on the committee, wrote the original board order about impervious surfaces.  Heuston wrote in an e-mail that: “I noticed many front yard gardens and back yards being converted to asphalt parking lots becoming increasingly the norm and also noted (confirmed by city solicitor) that nothing in our code of ordinances or in zoning code could regulate that or stem the tide.”

What kind of permit do you need to pave your front or back yard in Somerville?  Most likely, none.  Proakis reported Monday night that residents only need a permit to pave their properties if the project requires cutting the curb (to install a driveway).  Somerville’s zoning requires that landscaping take up 10 to 25 percent of lots, which one might think would assure some grass or garden on every property.   Not so: pavement currently counts as landscaping, to allow for patios, as long as it is not officially used for parking.  Patio or parking lot?  The latter can be hard to prove, as Proakis described; one day, the car is parked there, the next day, when a neighbor reports the yard parking lot, the car moves.

Proakis presented ideas that the Office of Strategic Planning and Community Development (OSPCD) has generated for regulating paving.  Proakis proposed requiring a certain percentage of pervious surfaces on lots and regulating runoff onto the street and neighboring properties.  He suggested that Somerville adopt the state stormwater standard, which mandates that a development on any lot cause no additional runoff and reduce runoff when possible.  He also suggested reviewing the landscaping requirements and possibly changing the definition of landscaping to exclude pavement.

Alderman Heuston said that flooding highlighted the need to create more permeable services in Somerville.  Flash floods the weekend of July 10 and 11 closed the Somerville Police station, damaged 26 police vehicles, and left a Somerville woman stranded in 18-feet of water under the Assembly Square Bridge.  The Police Station flooded again in August.

Yet flooding is not the only problem worsened by impermeable surfaces, as Ward 6 Alderman Rebekah Gewirtz, also on the Committee on Parks and Open Space, described: “It increases the heat island effect, contributing to global warming, costs the city more money in storm water run off processing ($11 million per year).”  The heat island effect is when a city is warmer than surrounding areas.  Blacktop and roofs, which absorb light and heat, contribute to that effect. Gewirtz has been investigating ways to encourage “green roofs,” or rooftop gardens, which, in her words, “trap storm water run off, reduce the heat island effect, and improve the insulation of homes in both the summer and winter.”

The Committee will continue its discussion of impermeable surfaces at a public meeting on October 25 at 6 p.m.