Narrator: Nutrient pollution is one of the most
widespread, costly and challenging
environmental problems in America today.
Excessive amounts of nutrients can lead to algal
blooms and shorelines clogged with seaweed.
This results in lost fish and shellfish habitat.
The waters of Cape Cod, Massachusetts are
increasingly nutrient impaired, largely from
excess nitrogen in wastewater and
stormwater.
Karen Simpson: Studies tell us that nitrogen
reductions are necessary across the Cape in
order to ensure that we have clean water to
support our fish and shellfish habitat and also
in order to support recreational uses such
as swimming, boating and fishing that Cape Cod
is known for.
Narrator: EPA, the State of Massachusetts
Department of Environmental Protection, the
Cape Cod Commission and community partners
on the Cape are working together to address
these issues. Two towns on Cape Cod were
selected to receive technical assistance from
EPA to pilot innovative green Infrastructure
Best Management Practice or BMP retrofits
designed to capture and treat nitrogen in
stormwater.
Robert Duncanson: So the town of Chatham
proposed this BMP to EPA a number of years
ago for one very good reason, right down the
street is what's known as Oyster Pond. And
we've identified water quality issues here a
number of years ago. First, being bacterial
contamination because the pond is used
extensively for swimming, fishing and shell fishing.
And then starting in the 1990s we
identified nutrient impacts to Oyster Pond. We
have a road immediately adjacent to us called
Oyster Pond Furlong but underneath that road
there is a 36-inch diameter concrete pipe that
conveys storm water from about 16 acres of
upland area. So what happened here is the
existing storm water pipe was intercepted with
a new pipe which diverts a portion of that
storm water flow into the BMP where it then
travels through an underground gravel bed
which is been designed specifically to retain
that water for a certain period of time and
allow bacteria that are naturally occurring in
that water to remove the nitrogen. That
nitrogen is converted to nitrogen gas and goes
back up into the atmosphere. And what
happens during a heavy rainfall event what you
see in front of us will actually fill up with water
and then gradually over time that water will
percolate down through the system and then
discharge back into the natural wetland stream
that's just off the site. And from there it flows
down into Oyster Pond.
Narration: This Chatham BMP is designed to
treat an area of almost 16.9 acres containing
9.29 acres of impervious surfaces. While the
Barnstable BMP is designed to treat
approximately 6.9 acres containing 4.6 acres of
impervious area.
Dale Saad: The water that was coming out of
the outfall into the Inner Harbor is actually
coming from all the way up from our airport
area. Some of it is commercial, some of it is
home and residential and some are just a
quaint downtown area. Whatever we're putting
on the ground is getting into the system. This
became a park with a wonderful brick parkway
that goes through it that connects different
beaches and the waterways of the town. So
people could easily move about and enjoy the
area. We wanted to preserve that walkway and
also the park setting and the gravel wetland
was a perfect inclusion into this environment.
And that it adds actually a visual location for
people to focus on nature and to really learn
and be educated about what was going on in
our waterways and how we can correct this.
Nick Christofori: This particular BMP, since we
did not have room to size for a larger storm
such as the 1-inch water quality volume, this
BMP is sized to treat a .3-inch runoff event. And
there's been research done in the past by UNH
and others that shows as much as 80% of
nitrogen within storm water is present within
these small storm events. So really even though
this BMP is relatively small by typical design
standards it really is capturing and removing a
lot of the nitrogen from this storm water.
Narrator: EPA estimates that if properly
maintained, these BMPs will collectively treat
about 1.75 million gallons of nitrogen-
containing stormwater runoff per year; or
about 42% or better of the available nitrogen
load from impervious surfaces draining to these BMPs.
Dale Saad: And this system is going to help the
town of Barnstable relieve some of the issues
we have with the marine outfall that's going in
the Inner Harbor, both sediment and also
nutrients. It contaminates our shellfish beds
our swimming areas. People come to the Cape
not for our mountains but for our waterways
and we want to protect them.
Robert Duncanson: And unfortunately here on
Cape Cod real estate is very difficult to come
by. In many aspects the only area of the town's
have is right along the side of the road. But I
think we showed here that we can take a parcel
that was originally set aside for conservation,
still maintain a lot of the conservation aspects
of that parcel, but also deal with the nutrient issue.
Dale Saad: One of our neighbors is Cape Cod
Maritime Museum. They have a STEM program
with children and they're very interested in
utilizing this as part of their educational
program.
Robert Duncanson: We do want to maintain it
as an asset to both the neighborhood and the
community while ensuring that the storm water
function continues to meet the goals that EPA
and the town have tried to achieve.
Karen Simpson: EPA will continue to work with
the state and its partners in order to
understand how systems like these work to
remove nutrients in stormwater, not just on the
Cape but in other areas that may be
experiencing similar issues. We look forward to
implementing innovative approaches that will
enhance the resilience of these important and
valuable coastal waters and ecosystems. 136 00:06:07,350 --> 00:06:07,150