The Neponset River Watershed
Association has been working with the Milton Department of
Public Works over the last several y ears to improve water quality
within Pine Tree Brook, via a variety of methods. The Pine Tree Brook Neighborhood Association
also has mobilized community members to help with this
project.
Bioretention
cells have been built along the
stretch of Pine Tree Brook between Blue Hills Parkway and Thacher
Street to catch and filter street runoff (also called "surface water") from adjacent
streets. Originally, this polluted water was piped directly
into the brook from catchbasins in the street. This
process caused the brook to deteriorate. Now,
water from the underground pipes has been diverted into the
bioretention cells to be filtered, cooled-down,
and slowed-down before it enters Pine Tree Brook. Below
is photograph of one of the Pine Tree Brook biocells, taken in
fall 2009. View more pictures.
Learn
more about bioretention cells.

What
is the deal with street "runoff"?
Contaminants from
daily life pollute street runoff. For example, runoff contains
products from the burning of fuel, fertilizers and herbicides
from lawns, ice-melting materials from sidewalks, sand, and
seepage from people's garbage cans. Street runoff is also thermally
polluted; it's been warmed-up by its travels over dark-colored
driveways, streets and roofs. Also, water that's run over streets,
sidewalks, grass ("turf"), and then through pipes -
travels quickly. See how each of these characteristics
of runoff affects a brook, below.
If
a brook's pollution levels get high enough, certain
aquatic species can completely die out. As one species
vanishes, others follow; they are all inter-related in the
food web. Ultimately, the natural system of the brook becomes
increasingly deteriorated.
Fast-moving
water entered a brook over the ground or through a pipe can
erode the stream's banks. In turn, this clouds the water,
clogs the gills of stream-bottom insects, makes it harder for
aquatic wildlife to move around, feed or interact with one
another, and damages the eggs of fish and aquatic insects.
Every component of an aquatic system is important to the
health of a stream. So, when one species is hurt by poor water
quality, so are the other species - and the stream, as whole.
Warmed
water has less oxygen than usual. This can stress - and
eventually kill - aquatic wildlife. Dissolved oxygen is
important for breathing -
Learn
more about stream
and river ecology.
Now
that you understand why the filtering action of bioretention
cells is so beneficial for streams, let's get back to what
NepRWA and its project partners have done along Pine
Tree Brook.
Most
recently, NepRWA, the DPW and PTBNA worked together
to beautify one of the streamside bioretention cells. In early
September 2006, a crew of employees from the DPW
and NepRWA, members of PTBNA, and other Milton residents
planted a bioretention cell with Joe-Pye weed, Arkansas
bluestar, Steeplebush, Feather reed grass, New England aster,
Blue flag iris and Coreopsis. These plants are showy, hardy
species, and many are native to New England. They were chosen
because of their ability to tolerate the extreme growing conditions of the
bioretention cells - periods of saturated soils and standing
water,
extended periods of dryness, pollutants from street runoff,
etc. See plant pictures above and below. In spring 2007, the rest of the bioretention cells
were planted. In addition to the plantings, stormdrain markers and
other signage were posted in the vicinity of the brook to
help neighbors keep local water clean.
If
you have walked by the bioretention cells, you may have
noticed that they are filled with an
assortment of wildflowers, sedges, rushes and grasses. Some of these plants
originated from seed mixtures spread during the project, while
others were a result of seeds already in the soil or those carried by
the wind or via wildlife. Some plants you may have seen include Jewelweed,
Milkweed, Boneset, Indian blanket, Black-eyed Susans,
Smartweed, Pokeweed, Burdock, Common evening-primrose,
Chicory, Coreopsis, Yellow wood sorrel, Japanese knotweed,
Purple loosestrife, and thistle, among others.
To
learn more about this project, contact Carly Rocklen at rocklen@neponset.org
or 781-575-0354 x303. Contact Dick Russell at 617-696-3751 to find
out more about the Pine
Tree Brook Neighborhood Association.
Pictures
of bioretention cell plants: