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Home My WebLink About2019-05-08 Minutes 8 May 2019 Meeting Minutes Chairman Barbour called the Port, Waterway & Beach Commission (PWBC) meeting to order at ~4:00. Participant introductions were made; . The April 2019 meeting minutes were approved. Presentation: Kure Beach (KB), Refined Coastal Modeling (RCM) Robert Neal, PE. Goals: Corroborate US Army Corps of Engineers (USACE) design template. Assess template placement and volume alternatives. Evaluate 4-year alternatives providing equal infrastructure protection. Assess economic risks following a 15-year maintenance hiatus. The Fiscal Year (FY) 2019 coastal storm damage reduction (CSDR) project maintenance event and ongoing annual shoreline mapping will allow opportunities to evaluate Pleasure Island modeling results. M&N will provide a brief math exercise using FY19 costs reassessing potential savings from a CB 4-year maintenance cycle. Current Efforts CB and KB FY2019 CSDR Projects: Weeks Marine began placement on 17 February and completed placement on 29 April. Awaiting USACE confirmation, Weeks Marine completed the CB CSDR placing an estimated 1,060,552 cubic yards (cy), KB North with 407,921 cy and KB South with 410,055 cy. No tilling was required (project wide) by the resource agencies and dune plantings (sea oats) is to begin 13 May in Kure South. Atlantic Intracoastal Waterway (AIWW) Maintenance Dredging Contract: The USACE contractor Southwind has completed the Mason Creek AIWW crossing removing ~32,163 cy at an estimated cost of $426,000.00; sediment management was in confined disposal facility 241. Mason Inlet Relocation Project (MIRP): The 2019 annual engineering surveys as well as the bi-weekly waterbird management area surveys have begun. A 2019/2020 relocation event will be assessed following surveyed template volumes. Target goals include beneficial placement on Figure 8 and the inclusion of WB North. The WB North concept would demonstrate an island-wide capability, a supplemental effect on the Moores Inlet Drive movement influence. Carolina Beach Inlet (CBI): The Murden began a 10-day maintenance dredging event on 15 April. On 22 April, a 5-day extension was granted resulting in a 15-day event ending on 30 April. Approximately 21,951 cy were removed at an estimated cost of $365K. The agencies granted a window exception for use of the inshore dredge material management (IDMMS) site. Following the event, the USCG is anticipated to restore the buoy alignment and remove the navigation restriction. The next events are scheduled for early July and September (8-week intervals) in an attempt to meet USCG standards for the buoy tender Bayberry, an approximate 8 depth and 100 width. Following the USACEs April event accounting and as of July 1(FY20), the USACEs CB Inlet fund balance should be in the $1.3M to $1.4M range. CB, Beach Renourishment Evaluation Report (BRER): The tentative selected plan meeting occurred on 25 April. The Division and Head Quarters seemed hesitant to support a two borrow option within the narrative. An additional USACE interim project review meeting will be scheduled to further discuss. A Draft BRER is scheduled to be released for public comment in July. WB, Post Authorization Change Report (PACR); The PACR can move forward with a Directors Report (regional approval) as opposed to a Chiefs Report (DC approval) because the WB projects authorization remains active until 2036. The two borrow option will likely be held to the same CBRA interpretation as CBs BRER. The likelihood is re-enforced by the Regional dismissal of the WB post-Florence Project Information Report (PIR). The PIRs original narrative included the historical inlet borrow site and was rejected. The District is re- developing a scope that uses an offshore borrow and will resubmit to Division by 28 June. A Draft PACR is scheduled to be released for public comment in June. Public Comment: Kure Beach Refined Coastal Modeling April 10, 2019 Kure Beach Refined Coastal Modeling Goals Evaluate Potential Local Management Strategies for KB CSDR Project in case Federal Participation Falters Estimate Economic Risks Following a 15-Year Maintenance Suspension Assess Material Placement & Volumetric Alternatives for Locally Managed CSDR Project Evaluate 4-Year Alternatives for Providing Equal or Greater Infrastructure Protection 2 Kure Beach Refined Coastal Modeling Process Evaluate Current CSDR Placement Limits & Quantities to Determine if Enhanced Project Performance May Be Provided Through Design Adjustments. Uses GenCade, Delft3D, & SBEACH to Estimate Project Performance and Storm Level of Protection Benefits Delft3D –Focuses on Sediment Transport & Morphologic Changes Influenced by Long-term Coastal Processes GenCade –Evaluates Shoreline Recession & Longshore Transport Based on Multi-Year Wave Patterns SBEACH –Estimates Cross-Shore Storm Induced Erosion Expected in Extreme Weather Events 3 Modeling Approach USACE KB CSDR Material Placement Limits & Placement Quantities 4 Modeling Approach Kure Beach Reference Monuments 5 Shoreline Recession –15 Year Maintenance Suspension Estimated Structural Value Impacted 6 Shoreline Recession –15 Year Maintenance Suspension 7 Shoreline Recession –15 Year Maintenance Suspension 8 Shoreline Recession –15 Year Maintenance Suspension 9 Shoreline Recession –15 Year Maintenance Suspension 10 Shoreline Recession –15 Year Maintenance Suspension 11 Shoreline Recession –15 Year Maintenance Suspension 12 Kure Beach Refined Coastal Modeling DesignAlternatives 1 -7 Potential Template Alternatives Alt 1: USACE Template (CB21.5 –KB4.5; KB9.5 –KB20) –504,200 CY Alt 2: Reduced Template(CB21.5 –KB4.5; KB9.5 –KB20) –417,800 CY Alt 3: USACE Authorized CSDR Limits (CB20 –KB20) –547,000 CY Alt 4: USACE 50-Ft Width Extension (CB21.5 –KB4.5; KB09 –KB20) – 835,400 CY Alt 5: Feeder Approach (CB21.5 –KB20) –676,000 CY Alt 6: Mod 25-Ft Width Extension (CB21.5 –KB4.5; KB09 –KB20) – 690,300 CY Alt 7: 40/35/25-Ft Width Extension (CB21.5 –KB4.5; KB9.5 –KB20) – 667,125 CY *Volumes shown are based on the 2015 shoreline conditions. 13 Kure Beach Refined Coastal Modeling DesignAlternatives 1 -7 14 Kure Beach Refined Coastal Modeling Alternatives Maintained the USACE Recommended Dune & Storm Berm Features. Only the Construction Berm Width Varied. 15 Kure Beach Refined Coastal Modeling Design Alternatives Average Construction Berm Widths 16 Kure Beach Refined Coastal Modeling Sediment Transport (Delft3D Analysis) Estimated Volume Remaining –North Segment (CB20 to KB4.5) 17 Kure Beach Refined Coastal Modeling Sediment Transport (Delft3D Analysis) Estimated Volume Remaining-South Segment (KB09 to KB20) 18 Kure Beach Refined Coastal Modeling Shoreline Recession (GenCade Analysis) Estimated Shoreline Width Remaining (Individual Reference Monuments) 19 Kure Beach Refined Coastal Modeling Cross-shore Response to Storm Activity (SBEACH Analysis) Estimated Level of Protection (LOP) Provided For a 2-Yr, 5-Yr, 10-Yr, 25-Yr, 50-Yr, & 100-Yr Storm Event 20 Kure Beach Refined Coastal Modeling Cross-shore Response to Storm Activity (SBEACH Analysis) Estimated Level of Protection (LOP) Provided For a 2-Yr, 5-Yr, 10-Yr, 25-Yr, 50-Yr, & 100-Yr Storm Event 21 Kure Beach Refined Coastal Modeling Placement Volume for the Combined Template of Alt. 6 (South Segment) and Alt. 7 (North Segment) Placement Volume for Alternative 1 estimated at 504,200 CY 22 Kure Beach Refined Coastal Modeling Annualized Economic Benefit 23 Kure Beach Refined Coastal Modeling Overall Modeling Summary/Conclusions: Analysis Indicates the combined template of Alt 6 (south segment) & Alt 7 (north segment) should: Provide a 4-Yr maintenance interval with equivalent LOP (25-YR Storm Event) as the current 3-Yr strategy. Require an annual budgetary supplement of ~$150,000. Create an average 8-Ft shoreline across the CSDR project area throughout the 4-Yr maintenance interval. Modeling also corroborated Alternative 1 (USACE) as a viable alternative for a locally managed CSDR project under a 3-yr maintenance period. 24 Kure Beach Refined Coastal Modeling Thank you! Questions / Discussion Robert Neal, PE Moffatt & Nichol Ph: 910.218.7100Email: rneal@moffattnichol.com 25 Agenda 8 May 2019, 4:00 PM New Hanover County, Government Center Finance Conference Room, 500 4:00 Call to Order Welcome/Introductions Request approval of the April meeting minutes (emailed 16 April 2019). Presentation : Kure Beach, Refined Coastal Modeling . Abbreviated Current Efforts: Carolina Beach (CB) and Kure Beach (KB) Fiscal Year (FY) 2019 Coastal Storm Damage Reduction (CSDR) Projects placing ~407,921 cubic yards (cy). Weeks Marine completed N. Kure Beach on Friday Apr. 05th placing ~410,055 cy. Weeks Marine completed S. Kure Beach on Monday Apr. 29th th Dredge demobilized April 30. Unconfirmed total project volume placed ~1.88 million cy. Atlantic Intracoastal Waterway (AIWW) Maintenance Dredging Contract The Mason Creek AIWW crossing completed, 32,163 cy removed. The USACE FY20 AIWW plans and specs in development; easement efforts underway. Mason Inlet Relocation Project (MIRP) The annual upland and bathymetric surveys nearly complete. Carolina Beach Inlet (CBI) The April maintenance event was extended by five days based on 17 April USCG meeting. Final volumes and USCG buoy determination pending. WB, Post Authorization Change Report (PACR); Project Information Report (PIR) A USACE update on 18 Apr, proposing two borrow options within PACR narrative. The USACE is re-scoping the post-Florence PIR, offshore borrow mandate. CB, Beach Renourishment Evaluation Report (BRER) A USACE update on 18 Apr, proposing two borrow options within narrative. Tentative Selected Plan conference call, 25 Apr, apparent USACE vertical ladder consternation regarding the two borrow option. Public Comment: Adjourn