2019-05-08 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
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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
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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.
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Kure Beach Refined Coastal Modeling
DesignAlternatives 1 -7
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Kure Beach Refined Coastal Modeling
Alternatives Maintained the USACE Recommended Dune & Storm Berm Features.
Only the Construction Berm Width Varied.
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Kure Beach Refined Coastal Modeling
Design Alternatives Average Construction Berm Widths
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Kure Beach Refined Coastal Modeling
Sediment Transport (Delft3D Analysis)
Estimated Volume Remaining –North Segment (CB20 to KB4.5)
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Kure Beach Refined Coastal Modeling
Sediment Transport (Delft3D Analysis)
Estimated Volume Remaining-South Segment (KB09 to KB20)
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Kure Beach Refined Coastal Modeling
Shoreline Recession (GenCade Analysis)
Estimated Shoreline Width Remaining (Individual Reference Monuments)
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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
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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
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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
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Kure Beach Refined Coastal Modeling
Annualized Economic Benefit
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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.
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Kure Beach Refined Coastal Modeling
Thank you!
Questions / Discussion
Robert Neal, PE
Moffatt & Nichol
Ph: 910.218.7100Email: rneal@moffattnichol.com
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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