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 | Making a difference, together
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 DPWandYOU.com | Making a difference, together 2
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 DPWandYOU.com | Making a difference, together 3
Project Scope Provide Shoreline Erosion Protection Along 2,700 LF of the Beverly Triton • Nature Park Shoreline DPWandYOU.com | Making a difference, together 4
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 • DPWandYOU.com | Making a difference, together 5
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. DPWandYOU.com | Making a difference, together 6
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 DPWandYOU.com | Making a difference, together 7
Reach 1 & Reach 2 1. Scientific Literature Review: Examples of sand retention performance of breakwater systems: Tombolo: Mayo Beach Source: Pope and Dean, 1986 DPWandYOU.com | Making a difference, together 8
Reach 1 & Reach 2 1. Scientific Literature Review: Examples of sand retention performance of breakwater systems. Salient: Bay Ridge Beach Source: Pope and Dean, 1986 DPWandYOU.com | Making a difference, together 9
Reach 1 & Reach 2 1. Scientific Literature Review: Examples of sand retention performance of breakwater systems. Salient: Beverly Triton Nature Park Source: Pope and Dean, 1986 DPWandYOU.com | Making a difference, together 10
Reach 1 & Reach 2 1. Scientific Literature Review: Current breakwater configuration is outside of desired range. Current Configuration Original Design DPWandYOU.com | Making a difference, together 11
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. Table – Comparison of Detached Breakwater Parameters in the Chesapeake Bay Breakwater Distance from Beach Breakwater Gap Length Original Ratio: Ratio: Response Projects Length (ft) (ft) Shoreline (ft) L s / L g L s / X Index L s L g X I s 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 DPWandYOU.com | Making a difference, together 12
Reach 1 & Reach 2 Proposed Solution: Extend breakwaters to 100’ feet long to decrease the gaps to 50’ wide. DPWandYOU.com | Making a difference, together 13
Reach 1 & Reach 2 3. Numerical modeling of ‘Before’ and ‘After’ Construction wave conditions: Before After DPWandYOU.com | Making a difference, together 14
Proposed Design of Breakwater Retrofit DPWandYOU.com | Making a difference, together 15
Recommended Solution for Optimal Shoreline Protection Proposed Current Configuration Configuration Proposed Configuration w/ Beach Nourishment Original Design DPWandYOU.com | Making a difference, together 16
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. DPWandYOU.com | Making a difference, together 17
Reach 3 Proposed Solution: Extend the revetment to an attached breakwater and construct a living shoreline. DPWandYOU.com | Making a difference, together 18
Reach 3 1. Numerical modeling of ‘Before’ and ‘After’ Construction wave conditions: Before After DPWandYOU.com | Making a difference, together 19
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. DPWandYOU.com | Making a difference, together 20
Reach 6 Proposed Solution: Extend breakwater , reconstruct and extend the groin and construct a living shoreline. DPWandYOU.com | Making a difference, together 21
Reach 6 1 . Numerical modeling of ‘Before’ and ‘After’ Construction wave heights: After Before DPWandYOU.com | Making a difference, together 22
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 DPWandYOU.com | Making a difference, together 23
Q & A – Shoreline Protection Project DPWandYOU.com | Making a difference, together 24
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