Stormwater Working Group – An Overview of Issues

On January 15, the Belmont Stormwater Working Group met to discuss priorities for 2015.  Many new Belmont High School students joined the meeting, so Walley and Anne-Marie first took some time to describe the basics of storm water-related issues and activities in Belmont:

  • There are two very different storm water-related issues: Pollution and Flooding
  • Both issues are exacerbated by having a lot of impervious surface very close to rivers and streams: this causes storm water to wash hydrocarbons, other pollutants, and soil into rivers and streams, which then become both polluted and shallower (from the bottom up).  The shallowness represents a reduction in the capacity of a river to handle large volumes of storm water during heavy rain storms, resulting in flooding.
  • Most of Belmont is in the Alewife Brook sub-watershed, which is currently about 47% impervious.  Anne-Marie distributed historical aerial photos from 1938 versus later years and explained the history of Belmont’s transformation from an agricultural community with lots of pervious surface to a residential community with 86 miles of impervious roads and driveways and buildings
  • Walley explained the importance of neighbors talking to neighbors to raise awareness of the impact of the actions of uphill neighbors on downhill neighbors during storm events.  From a show of hands, only two participants lived in the low-lying Winn Brook neighborhood, making for an entertaining dialog between Winn Brook residents and the rest of the group for the rest of the meeting.
  • Both Pollution and Flooding are also exacerbated by increased rainfall from climate change.  Rainfall data collected through 1958 were used to estimate that the 100-year storm was 6.5 inches.  Additional rainfall data collected through 2008 indicate that the 100-year storm is now 8.8 inches.
  • Significant accomplishments of the Belmont Stormwater Working Group in 2014 include:
    • Successfully advocated for Belmont storm water regulations to incorporate up-to-date rainfall data when assessing compliance by new developments
    • Contributed to the 604B project which delivered high-level concept diagrams for rain gardens at the high school and library. These projects are designed to address pollution issues.  Belmont Manor already has a rain garden, which was installed to comply with Conservation Commission conditions.
    • Provided the town with a  porous pavement brochure to educate homeowners planning to repave their driveway. Leader Bank has already installed porous pavement, which was installed to comply with Conservation Commission conditions. At Fresh Pond in Cambridge, a trail with porous pavement was recently opened near the water purification plan. Frank encouraged people to experiment with pouring water on these surfaces to see them in action!
    • Identified our first depaving project, scheduled for the Spring of 2015
  • The book “The Big Thirst, the Secret Life and Turbulent Future of Water” by Charles Fishman was recommended by Betty Krikorian
  • The movie “Dirt, The Movie” was recommended by Anne-Marie, who had just seen it at the Cambridge water purification plant
  • The MIT water club, “the leading network for water research and innovation at the Massachusetts Institute of Technology”  and the December 2014 MIT water summit were recommended by Betty as well

There was an active intergenerational discussion about a variety of topics, including how porous pavement is made, how it needs to be maintained (e.g. vacuuming every few years to keep it porous), how it doesn’t work as well when installed on top of rock or clay, what the role of the Conservation Commission is.  Anne-Marie described some recent work in Cambridge to encourage citizens to access municipal data to help the government address community problems (e.g. a Climate Co-lab initiative about the Urban Heat Island effect and a Cambridge Open Data initiative). There was discussion of GIS data and its relevance to the 604B project and other “green” storm water management projects.

Contributed by Anne-Marie Lambert