Sustainable Approaches to Coastal Design and Adaption to Sea Level Rise
Shannon E. Cunniff, Director, Coastal ResilienceWCEL Workshop2 February 2017
Helping People, Economies and the Environment Thrive
Building on the Louisiana Experience
• Economic Growth• Coastal
Community Protection
• Coastal Restoration
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Coastal Defenses
• Integrate natural and manmade defenses• Multiple Lines of Defense Strategy
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Shellfish & coral reefs = low breakwaters.
Vegetated dunes better withstand waves & provide attractive habitat
Maritime forests reduce wave & wind energy, capture debris; wetlands can attenuate waves.
Drainage, elevation, retention systems, relocation
1: USACE, 2015
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Important QuestionsPart I
• What are nature-based solutions?– a.k.a. Natural Infrastructure, Green Shores, Living Shorelines, Eco-
Based Disaster Risk Reduction, et al.
• Where and how do they work?
Part II
• Why would a community choose natural-based solutions?
Part III
• Lessons on creating comprehensive solutions for your community’s needs
Shore Re-nourishment
Credit: Ecoshape
Credit: Woods Hole Group
• Manage sediment as a resource
• Take advantage of littoral processes
• Keep vegetation & washed up algae
Credit: Dr. Brett Milligan
Dune Restoration
Reduce coastal erosion
Reduce nuisance
floods
Reduce force &
height of waves
Stop or reduce storm surge
beach builders & wave chew toys
Wetlands Restoration
Credit : Delaware NERC
Credit: Norfolk, VA
Slow inland water
transfer
Reduce force &
height of waves (<2’
– 5’ )
Can reduce
impact of stormsurge
Improve water quality
Credit: CRCL
Re-establishing lost connections & processes
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Oyster Reefs
Reduce coastal erosion
Reduce force & Height of short
waves (<2’)
Improve water quality
Speed bumps
Greener Gray Solutions • Breakwaters
– Concrete & forms • Tidepool, Fish, Oyster
Habitats
Photo credit: Econcrete
• Seawalls– 3 design features: Light,
shallow habitat w gravel, wall texture
• Salmonid migration, habitat for marine inverts
Credit: City of Seattle
“Hybrid” Solutions
• Living Shorelines: sills & wetlands
– East Coast Bays • VA, MD, DE, NC, SC,
AL, etc.
– Riparian areas• NY, NJ
Integrated Solutions
Part I
• What are nature-based solutions?– a.k.a. Natural Infrastructure, Green Shores, Living Shorelines, Eco-
Based Disaster Risk Reduction, etc.
• Where and how do they work?
Part II
• Why would a community choose nature-based solutions?
Part III
• Lessons on creating comprehensive solutions for your community’s needs
Important Questions
Lower Cost
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• Oyster reef breakwaters ~ $1M/mile Standard rock breakwaters cost1: $1.5-3M/mile
• Wetlands w/ sills: $50 - 500/ft Bulkheads/riprap2: ~$500 - 1,200/ft
Community hybrid soft shore − 3 scenarios: ranged between 30 – 70% less
costly than traditional hard approach seawall3
1: Dow et al., 2013; 2. CBF, 2007; 3: Lamont et al., 2014
Multiple Benefits
Sustainable
• Keep pace with sea level rise– Dunes & oyster reefs can grow
• More effective with age– Surface and root densities– Overall width and height
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Important QuestionsPart I
• What are Nature-Based Solutions?– a.k.a. Natural Infrastructure, Green Shores, Living Shorelines, Eco-
Based Disaster Risk Reduction, etc.
• Where and how do they work?
Part II
• Why would a community choose nature-based solutions?
Part III
• Lessons on creating comprehensive solutions for your community’s needs
Comprehensive Planning
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Reactive• Scramble to spend
• Power competition
• Impulse to return to what was familiar
Deliberative• Time to think through
community goals and build consensus pre-disaster
• Maximize opportunities next recovery affords
• Greater potential for innovative funding
• Pilots to prove concepts
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Adaptive Governance• Unite coastal protection & restoration under a single
agency with co-equal goals– Articulate clearly the priorities necessary to achieve
comprehensive coastal protection– Develop, implement, and enforce a comprehensive coastal
protection and restoration master plan.
Credit: LA CPRA
Yields a Comprehensive Plan for the Mississippi Delta
Generating Big Ideas – The Art of Inspiring
• Changing Course – EDF – Design teams from around the
world created innovative visions for how to achieve a more sustainable Lower Mississippi River Delta
• Structures of Coastal Resilience
– Rockefeller Foundation, after Super Storm Sandy
– Universities: Design; Architecture; Science
• Sediment diversions higher in the delta
• New navigation inlet
• Need to address migration of people
• Amphibious suburb
• Fingers of High Ground
Generating Vision & Buy In
• Room for the River
– Netherlands’ Rhine, Meuse & Scheldt Rivers Delta
Nijmegen
• Rebuild by Design
– Designs underway using similar principle of public collaboration
Generating Vision & Buy In
• Participatory Design
• Deliberative Democracy
• Crowd Co-Design
• “Dutch Dialogues”
Common elements:• Multiple disciplines
• Bring experts & citizens together
• Two-way education• Time investment• Infusion of capital
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PLANNING TEAM
252017 Coastal Master Plan
SUPPORTED BY:
TECHNICAL TEAMCOLLABORATIVE TEAM OF OVER 70 EXPERTS
262017 Coastal Master Plan
272017 Coastal Master Plan
FRAMEWORK DEVELOPMENT TEAM
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