|
As the Mad River Valley community happily welcomes spring and warmer temperatures
trickle into our Vermont valley, we must again revisit the effects of
run-off into the river. We all love spending time along the river
during the spring and summer, However, as the summer months quickly
approach, we also need to consider the cleanliness of the river
before jumping in.
In the more
urbanized areas of Vermont, particularly Chittenden County,
stormwater runoff has become quite a concern in recent years. Though
the Mad River watershed does not have the same level of development
as those areas, scientists studying the Mad River identified several
sub-watersheds where the area occupied by impervious cover is at or
approaching levels that have been shown to create water quality
issues.
The Bridge Street
Marketplace is a diverse collection of businesses located in historic
Waitsfield. The dirt parking lot servicing the shops is located
adjacent to the river. Due to the location of the lot, sediment and
polluted run-off discharges directly into the river at the site.
Friends of the Mad River, a local watershed group, was recently
awarded grant funding to build a rain garden at the Bridge Street
site. The lot is owned by the Historic Bridge Street Condominium
Association who has already agreed to the rain garden.
Like any garden, a
rain garden can serve many functions while still serving an
aesthetically pleasing view to any passer by. Rain gardens are
designed to capture and absorb rainwater and snowmelt known as
“stormwater runoff”. The garden slows the runoff entering a site,
thus controlling the water quality and quantity before releasing it
into the landscape (river in this case). When stormwater runs off of
impervious surfaces such as parking lots, compacted soil, roofs and
roads, it accumulates pollutants such as nitrogen and phosphorus,
bacteria from animal waste, oil and grease, and other heavy metals
from vehicles. The runoff is then either collected in a stormwater
drain that discharges into a lake or river or enters the water source
directly.
At the Bridge
Street Marketplace site, stormwater runoff from nearby buildings,
roads and the parking lot enters directly into the Mad River causing
flooding and stream bank erosion. Andres Torrizo of Watershed
Consulting and a Bridge Street business member, is completing the
design of the rain garden. After surveying the landscape, Andres
will design an appropriately sized rain garden for the north end of
the lot, where run off is most prominent.“ Runoff from the north
end of the Bridge Street Shops parking lot currently drains directly
into the Mad River without any treatment, so we would like to route
that watershed area into a stormwater treatment system in order to
improve the water quality and decrease the volume of runoff before it
discharges into the river,” says Torrizo.
Depending on the
size of the garden and the surface area of the site (in this case the
parking lot is mostly flat) intentional depressions in the landscape
can also be designed to absorb excess water and make the most of
precipitation and water entering the site. According the Winooski
Natural Resources Conservation District, the runoff that is filtered
through a rain garden will be treated at a rate 30% greater than that
of a typical backyard lawn. Other benefits include slowing potential
floods and erosion from the road; decreased need for maintenance and
use of fertilizers; increase in wildlife habitat for birds,
butterflies and other beneficial insects; provide a great
microclimate; etc. Most likely, the rain garden will require very
little upkeep, with exception of moderate weeding in the first year
and cutting back dead growth annually in early spring.
The garden will
consist of various perennial grasses, shrubs and some small trees
which will most effectively filter particulates and other pollution
from run-off. An example of some of the plant species to consider
include, but are not limited to: Goatsbeard (Aruncis dioicus),
Purple Leaf Bugbane (cimicifuga ramosa), Royal Fern (osmunda
regalis) commonly known as Fiddleheads, Drooping or Pendulous
Sedge (carex pendula), Tusock Sedge (carex stricta),
Black-eyed Susan (Rudbeckia hirta), etc. A rain garden
manual for any homeowner or business and detailed list of plants
appropriate for Vermont rain gardens can be found at the Winooski
Natural Resources Conservation District website at
www.vacd.org/winooski
The proposed rain
garden for the Bridge Street Marketplace will be installed by the
Friends of the Mad River and local volunteers in late summer 2009.
FMR Watershed Coordinator, Caitrin Noel concludes, “"This
project will not only directly address a water quality issue, but the
site is highly visible making the project a great opportunity to do
some education about stormwater. We are just on the cusp of beginning
to have issues from stormwater in the Mad River watershed. If people
start thinking about stormwater now, and using smart development
techniques, we can go a long way in avoiding future problems."
For further
information, questions or to volunteer please contact Caitrin Noel at
friends@madriver.com
|
|
