MassDOT Case Studies in Tidal Restoration...9 Culvert Replacement Benefits •Improve tidal flushing to the marsh –Improve salt marsh, reduce Phragmites –Improve quality of fishery
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MassDOT Case Studies in Tidal RestorationCrescent Marsh - Saugus, MA
Bass River – Dennis, MA
September 11, 2018
Northeastern Transportation & Wildlife Conference
Susan McArthur, MassDOT HWY Environmental
Ryan Lizewski, VHB
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• What is tidal flow restoration?
• What are the benefits and why is it important?
• How do we do it?
Introduction
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Crescent Marsh Culvert Replacement - SaugusVegetative
Community Area (SF)Percent
Coverage
Phragmites 550,092 56.6%
Salt Marsh 1,802 0.2%
Shrub-scrub 44,701 4.6%
Solidago 375,838 38.6%
Total 972,433 100.0%
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Culvert Replacement Benefits
• Improve tidal flushing to the marsh
– Improve salt marsh, reduce Phragmites
– Improve quality of fishery habitat
• Resiliency
– Increase culvert size from 48-inches to 6-foot by 6-foot box
– Reconnect Crescent Marsh with Bear Creek Estuary
Crescent Marsh Culvert Replacement - Saugus
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• No funds for project – How move forward?
– Added ~$2 million culvert replacement project to a nearby ~90+ million project.
Bundle PS&E into the nearby Belden Bly Bridge Project
– Used open services contract to develop project on accelerated schedule
• Needed to determined cost-effective replacement structure that would:
– meeting hydraulic performance standards
– Increase tidal flushing volumes to restore salt marsh
– provide greater resiliency to infrastructure in tidal environment.
Crescent Marsh Culvert Replacement - Saugus
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Permitting:
• Bridge Exempt Project
• 404 USACE PCN
• 401 Water Quality Certification
• MassDEP Bureau of Waste Prevention SW-45
• MassDEP Bureau of Waste Prevention SW-36
Crescent Marsh Culvert Replacement - Saugus
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Bass River Rail Trail Bridge – Dennis -Yarmouth
Bass River Bridge from early 1900’s, view to north
Bass River Bridge from 1990’s view to the south
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Channel Widening Benefits
• Improve tidal flushing
– Reduce nutrient concentrations w/in upstream bay & pond (evaluated by USACE in 2013)
– Improve salt marsh, reduce Phragmites,
– Improve quality of fishery habitat
• Improve navigability
– Increase 60’ channel to ~114’ channel
– Reduce velocities, improving navigability through structure
– Mariners get better alignment when approaching Route 6 bridges
Bass River Rail Trail Bridge – Dennis -Yarmouth
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Permitting
• 404 USACE Individual Permit
• USCG Section 9 Bridge Permit
• Coastal Zone Management Consistency Review
• Section 7 – NMFS, USFWS
• 401 Water Quality Certification (dredging and filling)
• Chapter 91 Waterways License
• MA Endangered Species Program
• Essential Fish Habitat Assessment
• MA Wetlands Protection Act (Dennis and Yarmouth)
Bass River Rail Trail Bridge – Dennis -Yarmouth
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Bass River Rail Trail Bridge – Dennis -Yarmouth
CCRT Crossing
BFE 6-ft
BFE 6-ft
NFIP Flood Insurance Rate Map (July 3, 1984)
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Bass River Rail Trail Bridge – Dennis -Yarmouth
CCRT Crossing
BFE 12-ft
BFE 9-ft
NFIP Flood Insurance Rate Map (July 16, 2014)
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