subwatershed restoration plan, franklin,...
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Subwatershed Restoration Plan, Franklin, MA
Julie Wood
Senior Scientist
Charles River Watershed Association
190 Park Road, Weston, MA 02493
781-788-0007
www.charlesriver.org
New England Interstate Water Pollution
Control Commission 23rd Annual Nonpoint Source Pollution Conference
May 15, 2012
Blue Development is a water-oriented approach to
urban development and redevelopment. Going
beyond “green” building, “blue” development
embraces designs for the built environment that
engage with every stage of the water cycle.
CRWA’s Blue Cities® Initiative
Meeting the Charles River TMDL:
A case study in Franklin, MA
Goal: Meet the Charles River Total Maximum Daily Load (TMDL) using the Blue Cities Approach
Identify restoration approaches that will restore hydrologic integrity
Develop “green infrastructure” concepts
Build on links to open space, public health and public realm needs
Total Maximum Daily Load for Nutrients in the
Upper/Middle Charles River, Massachusetts
Total Maximum Daily Load
(TMDL)
How much pollution is going into
the water (Existing Load)?
How much pollution can the water
handle and still be healthy (TMDL
Load)?
How do we get from the Existing
Load to the TMDL Load?
Upper CR Nutrient TMDL
Land Use Based
Study Area: Spruce Brook Pond Subwatershed
Size: Approximately 1 square mile
Land Use: Mixed Residential (high, medium and
low density)
Commercial
Industrial
Undeveloped
Transportation (I-495)
Development History Older commercial/industrial
(include historic mill buildings)
Some newer commercial w/BMPs
Older residential neighborhoods and newer subdivisions
Several Designated Discharge (DD) Sites
Creating a Subwatershed Retrofit Plan Methodology
Calculated required
phosphorus reduction
of 42% for study area
Non-structural
controls weren’t
considered
Credits were given for
structural BMPs
constructed after 2000
Subwatershed Existing Conditions Assessment
Subdividing the Subwatershed:
Drainage Areas
49 Drainage Areas
delineated based on:
Topography
Stormwater infrastructure
Property boundaries of
designated discharge (>2
acres impervious, in
commercial, residential or
high-density LU) sites
Green Infrastructure Control Systems
Infiltration trench
Infiltration
chamber
Rain garden
(infiltrates)
Bioretention
system (filters)
Gravel wetland
Ground Truthing and Obtaining Input
Site Visits Technical Review
Committee
Creating a Subwatershed Retrofit Plan Results
Developed two
scenarios:
Best professional
judgment plan
Optimized plan
www.charlesriver.org/projects/bluecities/Franklin_Plan_FINAL_small.pdf
Scenario 0: Best Professional Judgment Plan
Treatment systems
sited and sized
based on:
Site visit results
Available space
Project team input
Detailed designs
developed for 12
priority drainage
areas
Scenario 0: Priority Designs
Site 4B-2: Wachusett Street lot, Fletcher Field
Parking lot alternatives
Visualization: Vegetated Swale
Visualization: Rain Garden in Fletcher Field
Fletcher Field Construction, 2011
Fletcher field asphalt swale, 2010 Fletcher field vegetated swale, 2011
Fletcher Field Construction, 2011
Rain garden, with overflow at existing
catch basin, 2011
Reaching the target phosphorus reduction was an iterative process
Scenario 0: Best Professional Judgment Plan
Prioritize sites
Design treatment for most obvious
sites
Assess progress toward reduction goal
Consider more sites for
treatment
Scenario 2: Optimized Plan
Treatment systems sized by optimization algorithm
Optimization restraints: Minimize cost
Meet phosphorus reduction
Treatment system size allowed to vary (no upper or lower bounds set)
Treatment system type and location not allowed to vary
Proposed Drainage Area Retrofits by Scenario
S0
Plan S0 Plan S2
Phosphorous Removal by Drainage Area Plan S0 Plan S2
Drainage Area Retrofit Treatment Systems
Preliminary Cost Comparison:
Cost Per Pound of TP Removed
$0.00
$5,000.00
$10,000.00
$15,000.00
$20,000.00
$25,000.00
$30,000.00
$35,000.00
CRWA S0 CRWA S2 EPA S1 EPA S2 EPA S3
Scenario
Do
llars
($)
$/lb TP removed
Preliminary Cost Comparison
Cost Per Impervious Acre Treated
$0.00
$5,000.00
$10,000.00
$15,000.00
$20,000.00
$25,000.00
$30,000.00
CRWA S0 CRWA S2 EPA S1 EPA S2 EPA S3
Scenario
Do
llar
($)
$/impervious acre
Summary: Lessons Learned
Planning and Design Process
Site visits are vital
Detailed stormwater
infrastructure mapping is
very important
Not all treatment systems
are appropriate at all sites
Summary: Lessons Learned
Model Optimization
Model optimization can save you money!
Treat the first flush
Infiltration is the most cost effective strategy
Treating large volumes at one site may be cost effective but does not solve the whole problem
Summary: Lessons Learned
Design Results
Achieving the TMDL is possible but will require planning, time, and resources
Least expensive strategy may not be the most desirable strategy
Watershed or subwatershed level planning allows implementation to occur opportunistically while providing assurance that an overall goal is being achieved
Special Thanks!
Cox Charitable Trust
Horsley Witten
ESRI
Franklin Technical Advisory Committee
Jeff Nutting, Town Administrator
Bill Yadisernia, Robert Cantoreggi, Franklin DPW
James Esterbrook, Franklin GIS Department
Nick Alfieri, Franklin Conservation Commission
Beth Dahlstrom, Franklin Planning Department