Beverly Triton Nature Park Shoreline Protection Public Meeting - - PowerPoint PPT Presentation

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Beverly Triton Nature Park Shoreline Protection Public Meeting - - PowerPoint PPT Presentation

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Beverly Triton Nature Park Shoreline Protection Public Meeting Presented by: Anne Arundel County Department of Public Works with the Department of Recreation and Parks August 22, 2019 DPWandYOU.com | Making a difference, together DPWandYOU.com

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Beverly Triton Nature Park Shoreline Protection Public Meeting

Presented by: Anne Arundel County Department of Public Works with the Department of Recreation and Parks August 22, 2019

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Agenda

  • Introductions and Project Description – Department of Public Works
  • Shoreline Protection Schematic Design – BayLand Consultants & Designers, Inc.
  • Q&A on Shoreline Protection Project
  • Closing Remarks

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Shoreline Protection Project

  • Environmental Engineering Firm
  • Specializing in Projects at the Land-Water Interface
  • Stream & Ecological Restoration
  • Stormwater Management & Watershed BMPs
  • Marine, Dredging & Shoreline
  • Beverly Triton Nature Park Team:
  • Sepehr Baharlou, P

.E.

Project role – Project Manager

  • Anna Johnson, P

.E.

Project role – Coastal Engineer

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Project Scope

  • Provide Shoreline Erosion Protection Along 2,700 LF of the Beverly Triton

Nature Park Shoreline

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Project Scope

  • Goals and Objectives
  • Provide shoreline erosion control along the most vulnerable areas, previously prioritized as

Reaches 1, 2, 3 and 6

  • Maintain the current usability of the park
  • Minimize disruption to park visitors as much as practical during construction
  • Technical Approach
  • Focus on retrofitting stone structures
  • Protect sensitive areas with environmental and cultural resources
  • Use living shoreline techniques
  • No beach replenishment

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Design Considerations

(from Kick-off Meeting on February 7, 2019)

  • Construction Access
  • Waterside access only for minimal disturbance
  • Cost efficient option due to:
  • Location of the breakwaters
  • Minimal sand fill
  • Coastal Analysis
  • Use Automated Coastal Engineering System (ACES) and Steady State Spectral Wave Model

(STWAVE) to characterize coastal climate

  • Perform Extreme Value Analysis (EVA)
  • Use numerical and empirical models to design the retrofit and evaluate the performance of

proposed design.

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Reach 1 & Reach 2

  • Problem: We believe the

gaps between breakwaters are too large and allow too significant an amount of wave energy to reach the shoreline and erode the sand.

  • Solution: Reduce the gaps

between breakwaters by extending the existing structures.

  • Analysis:
  • 1. Review scientific literature
  • 2. Compare to similar projects
  • 3. Model ‘Before’ and ‘After’

Construction conditions

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Reach 1 & Reach 2

  • 1. Scientific Literature Review: Examples of sand

retention performance of breakwater systems:

Source: Pope and Dean, 1986 Tombolo: Mayo Beach

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Reach 1 & Reach 2

  • 1. Scientific Literature Review: Examples of sand

retention performance of breakwater systems.

Source: Pope and Dean, 1986 Salient: Bay Ridge Beach

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Reach 1 & Reach 2

  • 1. Scientific Literature Review: Examples of sand

retention performance of breakwater systems.

Source: Pope and Dean, 1986 Salient: Beverly Triton Nature Park

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Reach 1 & Reach 2

  • 1. Scientific Literature Review: Current

breakwater configuration is outside of desired range.

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Original Design Current Configuration

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DPWandYOU.com | Making a difference, together Table – Comparison of Detached Breakwater Parameters in the Chesapeake Bay Projects

Breakwater Length (ft)

Ls

Breakwater Gap Length (ft)

Lg

Distance from Original Shoreline (ft)

X

Ratio:

Ls / Lg

Ratio:

Ls / X

Beach Response Index

Is

  • S. River Farm Park

75 15 35 5.0 2.1 2.3 Mayo Beach 120 50 75 2.4 1.6 2.9 Essex Sky Park 100 35 50 2.9 1.5 3.0 Pleasure Island 140 110 200 1.4 1.1 3.6 Beverly Triton Design 75 75 100 1.0 0.8 4.1 Bay Ridge 90 110 140 0.8 0.6 4.3 Beverly Triton Phase I (Southern Breakwaters) 85 65 175 1.3 0.5 4.6 Beverly Triton Phase II (Northern Breakwaters) 71 79 198 0.9 0.4 4.8

Reach 1 & Reach 2

  • 2. Comparison with neighboring breakwater

systems:

  • Lower ‘Beach Response Index’ indicates better sand

retention.

  • Breakwaters at BTNP have a higher Beach Response

Index than other systems in Chesapeake Bay.

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Reach 1 & Reach 2

Proposed Solution:

Extend breakwaters to 100’ feet long to decrease the gaps to 50’ wide.

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Reach 1 & Reach 2

  • 3. Numerical modeling of ‘Before’ and ‘After’

Construction wave conditions:

After Before

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Proposed Design of Breakwater Retrofit

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DPWandYOU.com | Making a difference, together Original Design Current Configuration

Recommended Solution for Optimal Shoreline Protection

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Proposed Configuration Proposed Configuration w/ Beach Nourishment

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Reach 3

  • Problem: Beach is in

jeopardy of breaching and connecting Small Pond to the Bay; impacting habitat and the walking trail.

  • Solution: Reduce the wave

action at this area.

  • Analysis:

1.Model ‘Before’ and ‘After’ Construction conditions.

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Reach 3

Proposed Solution:

Extend the revetment to an attached breakwater and construct a living shoreline.

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Reach 3

  • 1. Numerical modeling of ‘Before’ and ‘After’

Construction wave conditions:

After Before

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Reach 6

  • Problem: Highest erosion

rate in the Park – 8 feet/year due to lack of sand source.

  • Solution: Reduce the

wave action at this area to increase sand retention.

  • Analysis:

1.Model ‘Before’ and ‘After’ Construction conditions.

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Reach 6

Proposed Solution:

Extend breakwater , reconstruct and extend the groin and construct a living shoreline.

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Reach 6

  • 1. Numerical modeling of ‘Before’ and ‘After’

Construction wave heights:

After Before

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Design Schedule for Shoreline Protection Project

  • Schematic Design (30%) – May 2019
  • Public Meeting – Today – August 22, 2019
  • State & Federal Permitting – September 2019
  • Design Development (60%) – January 2020
  • Public Meeting – February 2020
  • Construction Documents (100%) – April 2020
  • Public Meeting – April 2020
  • Begin Construction – July 2020

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Q & A – Shoreline Protection Project

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