massdot case studies in tidal restoration...9 culvert replacement benefits •improve tidal flushing...

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 - Saugus

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Crescent Marsh Culvert Replacement-Saugus

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Crescent Marsh Culvert Replacement-Saugus

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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


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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.


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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


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HEC-RAS Model Framework

NFIP Flood Insurance Rate Map 14


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HEC-RAS Profile and Calibration

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Water Surface Elevation Results

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Tidal Flushing and Runoff Volume Results

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Culvert Design – Plan View

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Culvert Design – Phasing

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Bass River Rail Trail Bridge – Dennis -Yarmouth

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Bass River Bridge from early 1900’s, view to north

Bass River Bridge from 1990’s view to the south

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Pre-Existing Crossing

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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


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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)


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CCRT Crossing

HEC-RAS Profile

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CCRT Crossing

BFE 6-ft

BFE 6-ft

NFIP Flood Insurance Rate Map (July 3, 1984)

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CCRT Crossing

BFE 12-ft

BFE 9-ft

NFIP Flood Insurance Rate Map (July 16, 2014)

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Bridge Design – Plan View

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Bridge Design – Section View

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Thank you

Susan [email protected]

857-368-8807

Ryan [email protected]

617-607-2684

MassDOT Case Studies in Tidal Restoration

massdot case studies in tidal restoration...9 culvert replacement benefits •improve tidal flushing...

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