Living Shorelines Project Long I sland Sound, W estport, CT Michael - - PowerPoint PPT Presentation

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Living Shorelines Project Long I sland Sound, W estport, CT Michael - - PowerPoint PPT Presentation

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Sustainable Shorelines Designs: Long I sland to Lake Erie Living Shorelines Project Long I sland Sound, W estport, CT Michael Ludwig Senior Biologist and Lead Regulatory Specialist 1 Presentation Outline Introduction Site Conditions

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Sustainable Shorelines Designs: Long I sland to Lake Erie

Living Shorelines Project

Long I sland Sound, W estport, CT

Michael Ludwig Senior Biologist and Lead Regulatory Specialist

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Presentation Outline

› Introduction › Site Conditions › Problem Definition › Constraints › Alternative Assessment and Evaluation › Design Solution › Installation › Performance / Evaluation › Lessons Learned / Conclusions

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Introduction

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OCC| COWI History

› Founded in 1983 › Local Firm – CT and NYC › 90+ Staff › ISO9001: 2008 Certified › Dedicated Solely to Waterfront Engineering Projects › Joined COWI in 2007

  • F. MICHAEL LUDWIG

SENIOR BIOLOGIST AND LEAD REGULATORY SPECIALIST

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SPECIALIZATION: Biology, Regulatory Services, Project Management YRS EXPERIENCE: 40 EDUCATION: Doctoral Courses, Physical Oceanography, SUNY Stony Brook, NY M.S. Fisheries Management, Long Island University B.S., Major Biology, Minor Marine Geology, Southern CT State University Formerly, Regional Regulatory Affairs Coordinator for the National Oceanic and Atmospheric Administration’s (NOAA) National Marine Fisheries Service (NMFS 10+ Years Consulting Experience for Shoreline Erosion Mitigation and Coastal Resiliency

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Natural or "Green" Resiliency for sustainable shorelines

› W hat is a Sustainable Shoreline?

› Shoreline structures that seek to protect shoreline wildlife habitat ecological functions and values, outdoor recreation, community quality of life, and water-dependent business attributes for future generations. › These designs to not attain full protection but provide for natural recovery by incorporating resiliency characteristics.

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› Located in Westport, CT › community of sailors and their families who share a common interest in sailboat racing. › With a 115-year racing tradition › CPYC is a participatory club with racing, social, cruising, and other sailing-related activities

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Site Conditions

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Location / Conditions

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› North Shore of Long Island Sound › Developed Shoreline (typical of western LI Sound) › Basin Protected from Long Island Sound Southern and Eastern Fetch › Open to the North › Erodible Soils – Sands, Silts & Gravel › Subject to Over-wash During Storm Conditions (Sandy)

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Problem Definition

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Site Conditions

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The m arina basin is m aintained by periodic dredging of glacial

  • utw ash sand and

gravel m aterial. The dredging and w ave activity cause erosion and basin infilling.

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Site Details

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› The shoreline within the upper, intertidal zone on the southern and western sides is populated with an eroding Smooth/ Saltmarsh cordgrass (Spartina alterniflora) community.

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Site Details

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Physical

* Erosion above and below salt marsh * Over-wash events

Biological

* High saltmarsh Vegetation - Minor * Intertidal saltmarsh Vegetation - Dominant * Common Reedgrass, Shrubs and Trees above * Fiddler Crabs and Oysters

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Site Details

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› The southern shore showed signs of erosion even through is was at the inner most portion of the marina and well protected(?).

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Site Details

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Site Details

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Shoreline Change Analysis

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Constraints

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Constraints

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› Engineered Solution: › "Perm anent," Cost Effective, & having Regulatory Acceptability

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Alternative Assessment and Evaluation

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Alternatives & I nsights

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› Steel Sheet Pile Bulkhead › Permanent and robust › Well understood design › Expensive › Potential regulatory issues Riprap › Permanent and robust › Well understood design › Moderately priced › Moderate regulatory concerns

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Alternatives

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› Vegetated Slope › Sustainability / survivability / maintenance › Design certification (level of protection?) › Relatively inexpensive (initial costs) › Regulatory friendly › Reinforced Vegetated Slope › Improved longevity › Better understood design › Moderately priced › Moderate regulatory concerns

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Alternatives

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› Reinforced Vegetated Slope › (Gabion Mats / Riprap Sill)

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Alternatives

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› Reinforced Vegetated Slope (Gabion Mats / Riprap Sill) › Improved longevity BUT has VANDALISM › Better understood design › Moderately priced › More regulatory concerns (fill) › Reinforced Vegetated Slope (Coir Mats) › Longevity relies more on vegetation development › Some design guidance › Moderately priced w/ fewer regulatory concerns (softer / non-permanent [ Bio-degradable] )

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Alternatives

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› Reinforced Vegetated Slope (Coir Mats)

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DESIGN SOLUTION

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Design Solution

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› Reinforced Vegetated Slope (Coir Mats) › Faster Implementation (Regulatory Acceptance) › Cost Effective › Monitor for Effectiveness (Revisit if or as needed) › Low wave energy / infrequent

  • vertopping – acceptable design

conditions › Acceptable level of protection / risk

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Design Solution

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INSTALLATION

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Coir Log Sill

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April 2015

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Coir Mat

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May 2015

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Comments on Installation

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› Material availability / substitution › Installation duration › Contractor experience (marine construction vs. environmental & landscape experience)

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Performance / Evaluation

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Performance

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Installation June 2015

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Performance

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Early July 2015

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Performance

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Late July 2015

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Performance

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August 2015

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Performance / Evaluation

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› Filled in nicely during first growing season › No issues during first summer / fall › Minimal damage during winter 2015/ 16 › Further growth during 2016 growing season

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Lessons Learned / Conclusions

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Lessons Learned / Conclusions

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› Needs: › Additional regulatory guidance / acceptance › Additional design guidance for soft solutions › Client education / understanding of risks › Contractor experience › Lessons Learned › Involve client early / often in decision process › Monitoring is critical to help with future designs and installations

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Thank You

Questions?

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FMLU@COW I .com