RiverGreen Business Park Stormwater Design Mystic River Watershed
Presentation to Mystic River Watershed Association 20 Academy Street Arlington, MA 02476
February 1, 2011
Mystic River Watershed
• 76 Square Miles • 22 Communities • Reading to East Boston • Boston Harbor • Malden River • 1 of 9 subwatersheds
Malden River/Everett • Flows from Melrose south to Malden • From Malden Square to the Mystic River the Malden River was dredged and straightened • Both sides of Malden River are heavily developed • Flow of river controlled by Amelia Earhart Dam • Prior 1965 Tidal: Regulated by Mass Waterways Program
Amelia Earhart Dam
Existing Site • 3 Airforce Road • Former GE Aircraft Facility • Vacant and Fenced Brownfield • Remediated to Industrial and Commercial Use Standards • 4.4 acres Paved Parking • Adjacent to 7 Acre City Park
Site Constraints MassDEP Stormwater Regulations: • Standard 3 – Recharge/Infiltration • Risk that Infiltrating May Cause Groundwater Contamination • Site Where Contamination Has Been Capped in Place City of Everett: • Airforce Road Drainage Poor • Entire Site Must Drain towards Malden River Low Impact Development Strongly Encouraged
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MassDEP 2008 Stormwater Regulations 1 – No new conveyances discharge untreated stormwater 2 – Post development discharge shall not exceed pre development 3 – Recharge post should approximate recharge pre (N/A) 4 – Remove 80% of Total Suspended Solids (TSS) 5 – Higher potential pollutant loads (Treat 1” water quality) 6 – Within a Zone II or flow to critical area (N/A) 7 – Redevelopment meets regs to maximum extent practicable 8 – Erosion & sedimentation control plan 9 – Long term operation & maintenance plan 10 – Prohibit illicit discharges
RiverGreen Business Park
Airforce Road
7 Acre Park
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Options for Best Management Practices • Infiltration Basins • Bio-Retention/Rain Gardens • Water Quality Swales • Porous Pavement • Infiltration Trenches • Gravel Wetland • Wet Pond • Dry Pond
Types of Low Impact Development Techniques • Drywells • Bio-Retention/Rain Gardens • Rain Barrels/Cisterns • Water Quality Swales • Green Roofs • Tree Box Filters • Vegetated Filter Strips • Reforestation
Four Season Hotel, Boston Source:greenroofs.com
Stormwater Management Current Conditions • Exist watershed 32.7 acres • Grass, pavement, vegetation • Elev change 1 ft to 12 ft • Slope 1% - 3% • Creeks north side and south side of parcel • Malden River – Design Point Proposed Conditions • Proposed multiple watersheds • Buildings, Pavement, vegetation • Numerous BMPs • No infiltration allowed • Raised site 2’ – 6’ • Slope 1% - 5% • Protected Wetlands • Malden River – Design Point
7 Acre Park
Underground Lined Stormwater Collection
7 Acre Park
13 Lined Stormwater Collection Systems Roof Runoff only Used for Irrigation TSS: N/A (clean)
Grassed Channel Source: www.canalelandscaping.com
7 Acre Park
• 8 Grassed Channels • Act as Forebays • Accepts Sheet Flow • Open Drainage • TSS: 25% - 50%
Bio-Retention/Rain Garden
7 Acre Park
• 2 Bio-retention areas • Soil and Vegetation • Landscaped • Open Drainage • TSS: 90% removal
Bio-Retention/Rain Garden
Wet Basin Source: Soquel Creek
7 Acre Park
Source: Soquel Creek Water District
• 3 Wet Basins • 3’ – 6’ depth of Water • Aesthetically pleasing • Open Drainage • TSS: 80% removal
Stormwater Constructed Wetland - Gravel
7 Acre Park
• 2 Gravel Wetlands • Wetland Vegetation • UNH Design • Treatment cells • TSS: 80% removal
Stormwater Constructed Wetland - Gravel
Extended Dry Detention Basin
7 Acre Park
• 1 Detention Basin • Water ~ 24 hours • Reduces flooding • TSS: 50% removal
Vegetated Filter Strip
7 Acre Park
• Throughout Site • Grass adjacent to drive • Slow velocities • TSS: 10% removal
Scenic Overlook
7 Acre Park
• ~ 50 Deciduous trees • ~ 40 Evergreen trees • ~ 260 Various Shrubs • Gazebo & 10 Benches • 10’ wide Riverwalk
RiverGreen Business Park
Permits Required for RiverGreen Park
• Conservation Commission – Order of Conditions
Why ESS? •
ESS Background & Qualifications: Firm with over 30 years experience of providing environmental consulting & engineering services 50+ scientists, engineers, and environmental specialists Two offices – Wellesley, MA & East Providence, RI Technical experts • • • • • • • •
Civil Engineering Municipal Permitting Watershed Science Geosciences & Hydrogeology Risk Assessment Wetlands & Wildlife Environmental Regulations Industrial Permitting
Communities ESS has worked in
ESS Group, Inc. Contact Information
Janet Carter Bernardo, P.E. ESS Group, Inc. www.essgroup.com Phone: 781.419.7751 E-mail: jbernardo@essgroup.com 100 Fifth Avenue, 5th Floor Waltham, MA 02451