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HomeMy WebLinkAbout2025-11-12 NHC Shoreline Mapping Program 2025 SummaryYear 12 – November 12, 2025 Presentation Outline Data Collection Survey Transects Survey Equipment Project Methodology Shoreline Change Volume Change Key Events: June 2024 – May 2025 Storm Activity Maintenance Activity Summary of Findings Shoreline & Volume Change (2024 - 2025) Inlet Conditions (2024 - 2025) Background Erosion Rates (2005/2006 - 2025) Nourishment Triggers (2014 - 2025) Q&A/Discussion 2 Presentation Outline Data Collection Survey Transects Survey Equipment Project Methodology Shoreline Change Volume Change Key Events: June 2024 – May 2025 Storm Activity Maintenance Activity Summary of Findings Shoreline & Volume Change (2024 - 2025) Inlet Conditions (2024 - 2025) Background Erosion Rates (2005/2006 - 2025) Nourishment Triggers (2014 - 2025) Q&A/Discussion 3 2025 Survey Dates: Mason Inlet Relocation Project: April 2025 (GBA) •14 Profiles (~500 and 1000 ft spacing) Wrightsville Beach: May 7, 2025 •29 Profiles (~ 1000 ft spacing) Masonboro Island: May 6, 2025 •22 Profiles (~ 2000 ft spacing) Freeman Park: May 19-20, 2025 •10 Profiles (~ 1000 ft spacing) Carolina Beach: May 19-20, 2025 •23 Profiles (~ 500 and 1000 ft spacing) Kure Beach: May 19-20, 2025 •21 Profiles (~ 500 and 1000 ft spacing) Fort Fisher: May 19-20, 2025 •19 Profiles (~ 1000 ft spacing) 4 Data Collection – Survey Transects Survey Reach Landmarks: 5 Data Collection – Survey Transects Sub-Reach (Profiles) Reach Length (ft) Start Point End Point MIRP F8 - South (5-14) 9,500 Beach Road South Bridge Rd MIRP F8 - Mason Inlet (1-4) 2,000 Mason Inlet Beach Rd South Wrightsville Beach - North/Mason Inlet (1-7) 5,631 Mason Inlet Duneridge Condos Wrightsville Beach - Central (8-17) 9,923 Duneridge Condos Trailborn Surf & Sound Wrightsville Beach - South (18-24) 6,149 Trailborn Surf & Sound North Jetty Wrightsville Beach - Masonboro Inlet (25-29) 2,925 North Jetty Masonboro Inlet (radial transects) Masonboro Island - North (1-6) 10,002 South Jetty Quarter of Island Masonboro Island - Central (7-12) 11,653 Quarter of Island Half of Island Masonboro Island - South (13-22) 17,638 Half of Island Carolina Beach Inlet Freeman Park - Carolina Beach Inlet (1-4) 3,110 Carolina Beach Inlet Carolina Beach Inlet (radial transects) Freeman Park (5-10) 5,510 Carolina Beach Inlet Freeman Park Carolina Beach - North (1-5) 2,838 Freeman Park Rock Revetment (Periwinkle Lane) Carolina Beach - Central (6-16) 8,248 Rock Revetment (Periwinkle Lane) Courtyard Carolina Beach Hotel Carolina Beach - South (17-23) 7,003 Courtyard Carolina Beach Hotel Atlantic Towers Kure Beach - North (1-6) 6,017 Atlantic Towers Kure Beach Fishing Pier Kure Beach - Central (7-10) 3,731 Kure Beach Fishing Pier Davis Rd Kure Beach - South (11-21) 5,594 Davis Rd Riggings Condos Fort Fisher - North (1-4) 2,461 Riggings Condos Ft. Fisher Revetment Fort Fisher - Central (5-13) 8,842 Ft. Fisher Revetment Half of Reach Fort Fisher - South (14-19) 5,496 Half of Reach New Hanover/Brunswick Co. Line FORT FISHER MASON INLET RELOCATION PROJECT WRIGHTSVILLE BEACH MASONBORO ISLAND FREEMAN PARK CAROLINA BEACH KURE BEACH Survey Transects & Sub-Reaches 6 Data Collection – Survey Transects 7 Data Collection – Survey Transects Survey Transects & Sub-Reaches 8 Data Collection – Survey Transects Survey Transects & Sub-Reaches 9 Data Collection – Survey Transects Survey Transects & Sub-Reaches Survey Performed By Geodynamics 10 ATV – TOPO DATA AQUISITION RV ECHO – HYDRO DATA AQUISITION Data Collection – Survey Equipment Data Collection Survey Transects Survey Equipment Project Methodology Shoreline Change Volume Change Key Events: June 2024 – May 2025 Storm Activity Maintenance Activity Summary of Findings Shoreline & Volume Change (2024 - 2025) Inlet Conditions (2024 - 2025) Background Erosion Rates (2005/2006 - 2025) Nourishment Triggers (2014 - 2025) Q&A/Discussion 11 Presentation Outline Mean High Water (MHW) = +1.4 ft NAVD88 Recreational Berm = +5.0 ft NAVD88 12 Project Methodology – Shoreline Change Calculate Volume Above Multiple Elevations: +1.4 ft NAVD88 – MHW -4 ft NAVD88 – Wading Depth -14 ft NAVD88 – Outer Bar -20 ft NAVD88 – Depth Of Closure (Upper Bracket) -30 ft NAVD88 – Depth Of Closure (Lower Bracket) Use Volumes For: Calculating Annual Volume Changes Calculating/Updating Background Erosion Rates 13 Project Methodology – Volume Change Volume Calculation Lenses 14 -40 -35 -30 -25 -20 -15 -10 -5 0 5 10 15 20 25 0 200 400 600 800 1000 1200 1400 1600 1800 2000 2200 2400 2600 2800 3000 El e v a t i o n ( f t N A V D 8 8 ) Distance From Baseline (ft) Profile Volume Analysis - Profile Calculation Lenses Foredune (Landward Most Dune Crest) MHW (+1.4 ft NAVD88) (+4.4 ft MLLW) Wading Depth (-4 ft NAVD88) (-1 ft MLLW) Outer Bar (-14 ft NAVD88) (-11 ft MLLW) -20 ft NAVD88 (-17 ft MLLW) -30 ft NAVD88 (-27 ft MLLW) Subaerial Beach (Top of Dune to MHW=+1.4 ft NAVD88) Wading Depth (MHW to -4 ft NAVD88) Outer Bar (-4 ft NAVD88 to -14 ft NAVD88) Offshore (-14 ft NAVD88 to -20 ft NAVD88) Offshore (-20 ft NAVD88 to -30 ft NAVD88) Example Volume Above -14 ft NAVD88 Project Methodology – Volume Change Data Collection Survey Transects Survey Equipment Project Methodology Shoreline Change Volume Change Key Events: June 2024 – May 2025 Storm Activity Maintenance Activity Summary of Findings Shoreline & Volume Change (2024 - 2025) Inlet Conditions (2024 - 2025) Background Erosion Rates (2005/2006 - 2025) Nourishment Triggers (2014 - 2025) Q&A/Discussion 15 Presentation Outline Spring 2024 to Fall 2024 - Fairly Calm Calm Summer - 2 Events With Elevated Offshore Wave Heights Just Over 2m (6.56 ft) Hurricane Debbie, PTC 8, Hurricane Helene Winter 2024 to Spring 2025 – Fairly Active 9 Events With Elevated Offshore Wave Heights Just Over 2m (6.56 ft) 1 Event With Elevated Offshore Wave Heights Just Under 3m (9.84 ft) 16 Key Events 2024-2025: Storm Activity 0 1 2 3 4 5 6 7 8 9 10 11 12 13 5/ 1 / 2 0 2 4 5/ 1 5 / 2 0 2 4 5/ 2 9 / 2 0 2 4 6/ 1 2 / 2 0 2 4 6/ 2 6 / 2 0 2 4 7/ 1 0 / 2 0 2 4 7/ 2 4 / 2 0 2 4 8/ 7 / 2 0 2 4 8/ 2 1 / 2 0 2 4 9/ 4 / 2 0 2 4 9/ 1 8 / 2 0 2 4 10 / 2 / 2 0 2 4 10 / 1 6 / 2 0 2 4 10 / 3 0 / 2 0 2 4 11 / 1 3 / 2 0 2 4 11 / 2 7 / 2 0 2 4 12 / 1 1 / 2 0 2 4 12 / 2 5 / 2 0 2 4 1/ 8 / 2 0 2 5 1/ 2 2 / 2 0 2 5 2/ 5 / 2 0 2 5 2/ 1 9 / 2 0 2 5 3/ 5 / 2 0 2 5 3/ 1 9 / 2 0 2 5 4/ 2 / 2 0 2 5 4/ 1 6 / 2 0 2 5 4/ 3 0 / 2 0 2 5 5/ 1 4 / 2 0 2 5 5/ 2 8 / 2 0 2 5 Si g n i f i c a n t W a v e H e i g h t ( f t ) NDBC Station 41110 - Masonboro Inlet, ILM2, NC May 1, 2024 - May 31, 2025 Average Wave Height: 3.1 ft Potential Tropical Cyclone Eight Typical Winter Storm Event Hurricane Debbie Hurricane Helene 17 Key Events 2024-2025: Maintenance Activity No Maintenance Activity During the 2024 – 2025 Monitoring Period REMINDER: Wrightsville Beach CSRM: January – March 2024 REMINDER: Mason Inlet Relocation Project: January –March 2024 Data Collection Survey Transects Survey Equipment Project Methodology Shoreline Change Volume Change Key Events: June 2024 – May 2025 Storm Activity Maintenance Activity Summary of Findings Shoreline & Volume Change (2024 - 2025) Inlet Conditions (2024 - 2025) Background Erosion Rates (2005/2006 - 2025) Nourishment Triggers (2014 - 2025) Q&A/Discussion 18 Presentation Outline Mason Inlet Relocation Project – Shoreline Position Changes (ft) Recreational Berm (+5.0 ft NAVD88): Average = -54.8 ft (Range = -265.7 ft – +35.6 ft) Mean High Water (+1.4 ft NAVD88): Average = -35.1 ft (Range = -128.4 ft – +45.7 ft) 19 *Survey Data Provided by the Mason Inlet Relocation Project Summary of Findings 11,500 ft Mason Inlet Relocation Project – Volume Changes (cy/ft) Significant Erosion From Transects 1 to 10 Due To Equilibration of 2024 MIRP Placement - Largest Losses Adjacent to Mason Inlet, Decreasing with Distance Accretion Adjacent to Northern Placement Limit Due To Littoral Transport From Project 20 *Survey Data Provided by the Mason Inlet Relocation Project Volume Change Above -14 ft NAVD88 = -23.8 cy/ft (-273,597cy) Summary of Findings 11,500 ft Mason Inlet Relocation Project – Volume Changes (cy/ft & cy) Above +1.4 ft NAVD88 (MHW) = -4.0 cy/ft = -46,087 cy Range = 18.7 cy/ft – 6.9cy/ft Above -4.0 ft NAVD88 (Wading Depth) = -12.6 cy/ft = -144,917 cy Range = -46.6 cy/ft – +10.0 cy/ft Above -14.0 ft NAVD88 (Offshore Bar) = -23.8 cy/ft = -273,597 cy Range = -102.3 cy/ft – +16.5 cy/ft Above -20.0 ft NAVD88 (Closure) = -21.9 cy/ft = -251,324 cy Range = -114.6 cy/ft – +22.0 cy/ft Above -30 ft NAVD88 (Offshore) = -21.1 cy/ft = -242,360 cy Range = -116.8 cy/ft – +19.3 cy/ft Overall Volume Loss Along The MIRP: Volume Losses Above -14 ft NAVD88 Totaled -273,597 cy, Equating To 60% Of 2024 Placement (459,821 cy) Which Is Higher Than Typical First Year Losses (≈30% – 40%). Losses Were Largest Adjacent To Mason Inlet, Decreasing With Distance From The Inlet. Area North Of The 2024 Placement Limits Experienced Minor Accretion. 21 Summary of Findings Wrightsville Beach – Shoreline Position Changes (ft) Recreational Berm (+5.0 ft NAVD88): Average = -35.9 ft (Range = -123.0 ft – +30.1 ft) Mean High Water (+1.4 ft NAVD88): Average = -31.5 ft (Range = -121.5 ft – +48.2 ft) 22 Summary of Findings 21,703 ft Wrightsville Beach – Volume Changes (cy/ft) Wrightsville Beach – Central Experienced Significant Volume Losses Due To Equilibration Of The 2024 CSRM Project Significant Volume Gains Adjacent To Mason Inlet & Minor Volume Gains Adjacent To Masonboro Inlet Volume Change Above -14 ft NAVD88 = -10.6 cy/ft (-229,474 cy) 23 21,703 ft Summary of Findings Above +1.4 ft NAVD88 (MHW) = -6.8 cy/ft = -147,225cy Range = -23.1 cy/ft – +6.7 cy/ft Above -4.0 ft NAVD88 (Wading Depth) = -10.9 cy/ft = -236,678 cy Range = -41.7 cy/ft – +23.4 cy/ft Above -14.0 ft NAVD88 (Offshore Bar) = -10.6 cy/ft = -229,474 cy Range = -65.8 cy/ft – +129.7 cy/ft Above -20.0 ft NAVD88 (Closure) = -9.2 cy/ft = -199,264 cy Range = -64.5 cy/ft – +151.9 cy/ft Above -30 ft NAVD88 (Offshore) = -7.6 cy/ft = -164,520 cy Range = -62.1 cy/ft – +156.6 cy/ft Overall Volume Loss Along Wrightsville Beach: Volume Losses Above -14 ft NAVD88 Totaled -229,474 cy Along Wrightsville Beach Oceanfront With Wrightsville Beach – Central Experiencing -332,625 cy Of Loss. Volume Losses In The Project Area Equate to 32% of the 2024 Placement (1,036,807 cy). Some Losses Were Captured in Wrightsville Beach - North and South (≈103,000 cy). Wrightsville Beach – Volume Changes (cy/ft & cy) 24 Summary of Findings 20 yr Average Background Erosion Rate = -8.6 cy/ft/yr (-187,544 cy/yr) -50 -40 -30 -20 -10 0 10 20 8001,0001,2001,4001,6001,8002,0002,2002,4002,600 El e v a t i o n ( f t N A V D 8 8 ) Distance From Baseline (ft) Wrightsville Beach Transect 27 2024 2025 Natural Replenishment of Borrow Area (Approx. 196 cy/ft) Wrightsville Beach Masonboro Island Wrightsville Beach (Masonboro Inlet) – Example Profile Historical Borrow Source For The Wrightsville Beach CSRM Project 25 Summary of Findings Wrightsville Beach (Masonboro Inlet) – Volume Change (cy) Combination of Several Survey Components & Calculations Masonboro Inlet - USACE Hydrographic Surveys Wrightsville Beach Spit - Geodynamics Laser Scanner Calculate Volume of the USACE Hydrographic Surveys & Wrightsville Beach Laser Scanner Data Within the Permitted Borrow Area, Above Authorized Depths (ranges from -20 ft MLLW to -30 ft MLLW) Filled in Data Gaps Between USACE Hydrographic Surveys & Wrightsville Beach Laser Scanner Data by Interpolating a Surface Filled in Small Data Gaps at Edges/Corners Using Adjacent Survey Elevations 26 Summary of Findings Wrightsville Beach (Masonboro Inlet) – Volume Change (cy) Volume Change March 2024 – December 2024 = +140,978 cy (+187,970 cy/yr) Volume Available (December 2024) = +403,465cy 27 Summary of Findings Masonboro Island – Shoreline Position Changes (ft) Recreational Berm (+5.0 ft NAVD88): Average = -13.4 ft (Range = -151.7 ft – +22.4 ft) Mean High Water (+1.4 ft NAVD88): Average = -0.4 ft (Range = -41.6 ft – +26.2 ft) 28 Summary of Findings 39,293 ft Masonboro Island – Volume Changes (cy/ft) Stability Along A Majority Of Masonboro Island With More Significant Erosion Adjacent To Carolina Beach Inlet 29 Volume Change Above -14 ft NAVD88 = +0.7 cy/ft (+26,529 cy) Summary of Findings 39,293 ft Masonboro Island – Volume Changes (cy/ft & cy) Above +1.4 ft NAVD88 (MHW) = -0.2 cy/ft = -9,296 cy Range = -4.5 cy/ft – +8.8 cy/ft Above -4.0 ft NAVD88 (Wading Depth) = +1.9 cy/ft = +76,400 cy Range = -9.4 cy/ft – +26.3 cy/ft Above -14.0 ft NAVD88 (Offshore Bar) = +0.7 cy/ft = +26,529 cy Range = -46.7 cy/ft – +42.7 cy/ft Above -20.0 ft NAVD88 (Closure) = -2.3 cy/ft = -92,283 cy Range = -54.5 cy/ft – +28.9 cy/ft Above -30 ft NAVD88 (Offshore) = -2.3 cy/ft = -89,198 cy Range = -56.1 cy/ft – +29.7 cy/ft Overall Volume Gain Along Masonboro Island: Minor Volume Gains Above -14 ft NAVD88 Totaled +26,529 cy Which Is Not Atypical Given The Small Background Erosion Rate In This Area. Erosion Adjacent to Carolina Beach Inlet Should Be Monitored Due To Changing Hydrodynamics Of The Inlet. 30 Summary of Findings 20 yr Average Background Erosion Rate = -1.8 cy/ft/yr (-72,161 cy/yr) Freeman Park (Carolina Beach Inlet) Due To The Alignment Of The Transects Across Carolina Beach Inlet, Not All Profiles Include A Dune, Berm, & Aerial Beachface; Therefore, Shoreline Change & Volume Change Calculations Were Not Performed 31 Summary of Findings -50 -40 -30 -20 -10 0 10 20 -200 0 200 400 600 800 1,000 1,200 1,400 1,600 1,800 2,000 2,200 2,400 2,600 El e v a t i o n ( f t N A V D 8 8 ) Distance From Baseline (ft) Freeman Park Transect 2 2024 2025 Freeman Park Masonboro Island Limited IDMMS Natural Replenishment (Approx. 64 cy/ft) Freeman Park (Carolina Beach Inlet) – Example Profile 32 Summary of Findings Minor Accretion Within Historical Borrow Source For The Carolina Beach CSRM Project, Significantly Less Than Previous Years -50 -40 -30 -20 -10 0 10 20 -200 0 200 400 600 800 1,000 1,200 1,400 1,600 1,800 2,000 2,200 2,400 2,600 El e v a t i o n ( f t N A V D 8 8 ) Distance From Baseline (ft) Freeman Park Transect 2 2018 2019 2020 2021 2022 2023 2024 2025 Freeman Park Masonboro Island Freeman Park (Carolina Beach Inlet) – Example Profile 33 Summary of Findings Historical Borrow Source For The Carolina Beach CSRM Project -30 -20 -10 0 10 20 -200 0 200 400 600 800 1,000 1,200 1,400 1,600 1,800 2,000 2,200 2,400 2,600 2,800 3,000 3,200 3,400 3,600 El e v a t i o n ( f t N A V D 8 8 ) Distance From Baseline (ft) Freeman Park Transect 3 2024 2025 Approx 100 ft NorthwardMigration of Channel Centerline Freeman Park Freeman Park Spit Adjustment Freeman Park (Carolina Beach Inlet) – Example Profile 34 Summary of Findings Freeman Park Spit Adjustment at Mouth of Inlet Freeman Park (Carolina Beach Inlet) – Volume Change (cy) 35 Summary of Findings Combination of Several Survey Components & Calculations Carolina Beach Inlet - USACE Hydrographic Surveys Freeman Park Spit - Geodynamics Laser Scanner Calculate Volume of the USACE Hydrographic Surveys & Freeman Park Spit Laser Scanner Data Within the Permitted Borrow Area, Above Authorized Depth (-40 ft MLLW) Filled in Data Gaps Between USACE Hydrographic Surveys & Freeman Park Laser Scanner Data by Interpolating a Surface Filled in Small Data Gaps at Edges/Corners Using Adjacent Survey Elevations Freeman Park (Carolina Beach Inlet) – Volume Change (cy) Volume Change 2024 – 2025 = +25,610 cy Volume Change 2019 – 2025 = +1,276,443 cy Volume Available (May 2025) = +1,377,660 cy 36 Summary of Findings Freeman Park – Shoreline Position Changes (ft) Recreational Berm (+5.0 ft NAVD88): Average = +5.9 ft (Range = -19.3 ft – +59.0 ft) Mean High Water (+1.4 ft NAVD88): Average = +16.3 ft (Range = -39.5 ft – +25.3 ft) 37 Summary of Findings 5,510 ft Freeman Park – Volume Changes (cy/ft) Volume Losses Along Majority of Reach Above Most Elevations Small Volume Gains Adjacent to Carolina Beach Inlet Due to Spit Growth 38 Volume Change Above -14 ft NAVD88 = -10.0 cy/ft (-54,947 cy) Summary of Findings 5,510 ft Freeman Park – Volume Changes (cy/ft & cy) Above +1.4 ft NAVD88 (MHW) = +4.1 cy/ft = +22,605 cy Range = -1.8 cy/ft – +16.0 cy/ft Above -4.0 ft NAVD88 (Wading Depth) = -0.8 cy/ft = -4,313 cy Range = -16.7 cy/ft – +19.8 cy/ft Above -14.0 ft NAVD88 (Offshore Bar) = -10.0 cy/ft = -54,947 cy Range = -42.6 cy/ft – +24.2 cy/ft Above -20.0 ft NAVD88 (Closure) = -9.3 cy/ft = -51,470 cy Range = -36.5 cy/ft – +12.7 cy/ft Above -30 ft NAVD88 (Offshore) = -10.8 cy/ft = -56,938 cy Range = -33.5 cy/ft – +9.3 cy/ft Overall Volume Loss Along Freeman Park: Moderate Volume Loss Above -14 ft NAVD88 Totaling -54,947 (-10.0) cy/ft. This Is Slightly Lower Than The Historical Background Volume Changes. Losses Were Largest Further From The Inlet With Small Volume Gains Adjacent To The Inlet Likely Due To Shoaling In The Absence Of Recent Dredging. As A Note, Overall Minor Volume Gains Were Experienced Above MHW. 39 Summary of Findings 19 yr Average Background Erosion Rate = -12.1 cy/ft/yr (-66,871 cy/yr) Carolina Beach – Shoreline Position Changes (ft) Recreational Berm (+5.0 ft NAVD88): Average = -8.5 ft (Range = -48.1 ft – +22.2 ft) Mean High Water (+1.4 ft NAVD88): Average = -11.8 ft (Range = -54.9 ft – +16.1 ft) 40 Summary of Findings 18,089 ft Carolina Beach – Volume Changes (cy/ft) Carolina Beach – North & Central Experienced Moderate Volume Losses From Erosion of the 2022 CSRM Project Carolina Beach – South Was More Stable, Benefitting From Southerly Transport of Project Material 41 Volume Change Above -14 ft NAVD88 = -6.6 cy/ft (-119,323 cy) Summary of Findings 18,089 ft Carolina Beach – Volume Changes (cy/ft & cy) Above +1.4 ft NAVD88 (MHW) = -1.7 cy/ft = -31,444 cy Range = -12.9 cy/ft – +5.1 cy/ft Above -4.0 ft NAVD88 (Wading Depth) = -3.9 cy/ft = -71,289 cy Range = -24.0 cy/ft – +6.4 cy/ft Above -14.0 ft NAVD88 (Offshore Bar) = -6.6 cy/ft = -119,323 cy Range = -32.7 cy/ft – +12.9 cy/ft Above -20.0 ft NAVD88 (Closure) = -9.3 cy/ft = -168,707 cy Range = -34.7 cy/ft – +11.5 cy/ft Above -30 ft NAVD88 (Offshore) = -10.8 cy/ft = -194,876 cy Range = -38.2 cy/ft – +12.2 cy/ft Overall Volume Loss Along Carolina Beach: Volume Losses Above -14 ft NAVD88 Totaled -119,323 cy (-6.6 cy/ft) Which Is Equivalent to 11% of 2022 CSRM Material Placement. This Is Lower Than The Previous Year, Which Is Expected, & Lower Than The Background Erosion Rate. Total Losses Since The 2022 CSRM Project Equate To -710,422 cy (≈63% of Project). Larger Volume Losses Above -20 ft NAVD88 and -30 ft NAVD88 Indicate Transport of Material Out Of The Vicinity. 42 Summary of Findings 19 yr Average Background Erosion Rate = -15.9 cy/ft/yr (-287,364 cy/yr) Kure Beach – Shoreline Position Changes (ft) Recreational Berm (+5.0 ft NAVD88): Average = -4.5 ft (Range = -22.5 ft – +29.1 ft) Mean High Water (+1.4 ft NAVD88): Average = -10.3 ft (Range = -30.0 ft – -29.8 ft) 43 Summary of Findings 15,342 ft Kure Beach – Volume Changes (cy/ft) Kure Beach Experienced Moderate Volume Losses From Erosion of the 2022 CSRM Project Losses Were Fairly Consistent In Magnitude Throughout The Reach 44 Volume Change Above -14 ft NAVD88 = -5.3 cy/ft (-82,055 cy) Summary of Findings 15,342 ft Kure Beach – Volume Changes (cy/ft & cy) Above +1.4 ft NAVD88 (MHW) = -0.5 cy/ft = -7,650 cy Range = -5.3 cy/ft – +7.1 cy/ft Above -4.0 ft NAVD88 (Wading Depth) = -3.0 cy/ft = -46,331 cy Range = -12.5 cy/ft – +11.6 cy/ft Above -14.0 ft NAVD88 (Offshore Bar) = -5.3 cy/ft = -82,055 cy Range = -19.5 cy/ft – +13.5 cy/ft Above -20.0 ft NAVD88 (Closure) = -7.4 cy/ft = -113,295 cy Range = -21.5 cy/ft – +19.7 cy/ft Above -30 ft NAVD88 (Offshore) = -3.5 cy/ft = -54,197 cy Range = -14.2 cy/ft – +14.8 cy/ft Overall Volume Gain Losses Kure Beach: Volume Losses Above -14 ft NAVD88 Totaled -82,055 cy (-5.3 cy/ft) Which Is Equivalent to 11% of 2022 CSRM Material Placement. This Is Lower Than The Previous Year, Which Is Expected, & Lower Than The Background Erosion Rate. Total Losses Since The 2022 CSRM Project Equate To -519,425 cy (≈67% of Project). Larger Volume Losses Above -20 ft NAVD88 Indicate Transport of Material Out Of The Vicinity. 45 Summary of Findings 19 yr Average Background Erosion Rate = -9.0 cy/ft/yr (-138,538 cy/yr) Fort Fisher – Shoreline Position Changes (ft) Recreational Berm (+5.0 ft NAVD88): Average = +0.2 ft (Range = -15.8 ft – +23.5 ft) Mean High Water (+1.4 ft NAVD88): Average = +3.4 ft (Range = -16.2 ft – +21.5 ft) 46 Summary of Findings 16,799 ft Fort Fisher – Volume Changes (cy/ft) Overall Stability Along The Reach, Only Minor Volume Losses Above -14 ft NAVD88 Significant Offshore Volume Gains At Southern End Of Reach 47 Volume Change Above -14 ft NAVD88 = -0.9 cy/ft (-14,971 cy) Summary of Findings 16,799 ft Fort Fisher – Volume Changes (cy/ft & cy) Above +1.4 ft NAVD88 (MHW) = +2.2 cy/ft = +36,410 cy Range = -3.4 cy/ft – +8.1 cy/ft Above -4.0 ft NAVD88 (Wading Depth) = +2.2 cy/ft = +37,301 cy Range = -8.8 cy/ft – +13.8 cy/ft Above -14.0 ft NAVD88 (Offshore Bar) = -0.9 cy/ft = -14,971 cy Range = -20.6 cy/ft – +22.9 cy/ft Above -20.0 ft NAVD88 (Closure) = +3.8 cy/ft = +63,608 cy Range = -16.8 cy/ft – +24.2 cy/ft Above -30 ft NAVD88 (Offshore) = +24.6 cy/ft = +413,523 cy Range = -1.7 cy/ft – +56.6 cy/ft Overall Volume Loss Along Fort Fisher: Minor Volume Losses Above -14 ft NAVD88 Totaled -14,971 cy (-0.9 cy/ft), Contrary To The Average Background Volume Change Rates of +2.2 cy/ft/yr (+36,631 cy). Minor Volume Gains Above MHW, -4 ft NAVD88, and -20 ft NAVD88 With Significant Volume Gains Experienced Above -30 ft NAVD88 Due To Small Offset In Profile Elevation Over Flat Offshore Portion Of Profile. 48 Summary of Findings 19 yr Average Background Erosion Rate = +2.2 cy/ft/yr (+36,631 cy/yr) Pleasure Island – Shoreline Position Changes (ft) Recreational Berm (+5.0 ft NAVD88) = -3.4 ft Mean High Water (+1.4 ft NAVD88) = -4.0 ft 49 Summary of Findings Pleasure Island – Volume Changes (cy/ft) Volume Change Above -14 ft NAVD88 = -4.9 cy/ft (-271,296 cy) 50 Summary of Findings New Hanover County – Unit Volume Change (cy/ft) 51 Summary of Findings UPDATE -100 -90 -80 -70 -60 -50 -40 -30 -20 -10 0 10 20 30 40 50 MI R P F 8 S o u t h MI R P F 8 M a s o n I n l e t Wr i g h t s v i l l e B e a c h N o r t h Wr i g h t s v i l l e B e a c h C e n t r a l Wr i g h t s v i l l e B e a c h S o u t h Ma s o n b o r o I s l a n d N o r t h Ma s o n b o r o I s l a n d C e n t r a l Ma s o n b o r o I s l a n d S o u t h Fr e e m a n P a r k Ca r o l i n a B e a c h N o r t h Ca r o l i n a B e a c h C e n t r a l Ca r o l i n a B e a c h S o u t h Ku r e B e a c h N o r t h Ku r e B e a c h C e n t r a l Ku r e B e a c h S o u t h Fo r t F i s h e r N o r t h Fo r t F i s h e r C e n t r a l Fo r t F i s h e r S o u t h Av e r a g e V o l u m e C h a n g e ( c y / f t ) Average Unit Volume Change by Elevation (2024 - 2025) South North Change Above +1.4 Change Above -4 Change Above -14 Change Above -20 Change Above -30 /M a s o n I n l e t Er o s i o n Ac c r e t i o n New Hanover County – Cumulative Volume Change (cy) 52 Summary of Findings UPDATE -500,000 -450,000 -400,000 -350,000 -300,000 -250,000 -200,000 -150,000 -100,000 -50,000 0 50,000 100,000 150,000 200,000 250,000 MI R P F 8 S o u t h MI R P F 8 M a s o n I n l e t Wr i g h t s v i l l e B e a c h Wr i g h t s v i l l e B e a c h C e n t r a l Wr i g h t s v i l l e B e a c h S o u t h Ma s o n b o r o I s l a n d N o r t h Ma s o n b o r o I s l a n d C e n t r a l Ma s o n b o r o I s l a n d S o u t h Fr e e m a n P a r k Ca r o l i n a B e a c h N o r t h Ca r o l i n a B e a c h C e n t r a l Ca r o l i n a B e a c h S o u t h Ku r e B e a c h N o r t h Ku r e B e a c h C e n t r a l Ku r e B e a c h S o u t h Fo r t F i s h e r N o r t h Fo r t F i s h e r C e n t r a l Fo r t F i s h e r S o u t h Cu m u l a t i v e V o l u m e C h a n g e ( c y ) Cumulative Volume Change by Elevation (2024 - 2025) South North Change Above +1.4 Change Above -4 Change Above -14 Change Above -20 Change Above -30 No r t h / M a s o n I n l e t Er o s i o n Ac c r e t i o n 2024 vs. 2025 (Total Change)Transects Reach Length avg shoreline change @ +5 ft NAVD88 avg shoreline change @ +1.4 ft NAVD88 avg volume change above +1.4 ft NAVD88 cumulative volume change above +1.4 ft NAVD88 avg volume change above -4 ft NAVD88 cumulative volume change above -4 ft NAVD88 avg volume change above -14 ft NAVD88 cumulative volume change above -14 ft NAVD88 avg volume change above -20 ft NAVD88 cumulative volume change above -20 ft NAVD88 avg volume change above -30 ft NAVD88 cumulative volume change above -30 ft NAVD88 Reach # ft ft ft cy/ft cy cy/ft cy cy/ft cy cy/ft cy cy/ft cy Mason Inlet Relocation Project 1-14 11,500 -54.8 -35.1 -4.0 -46,087 -12.6 -144,917 -23.8 -273,597 -21.9 -251,324 -21.1 -242,360 Wrightsville Beach* 1-24 21,703 -35.9 -31.5 -6.8 -147,225 -10.9 -236,678 -10.6 -229,474 -9.2 -199,264 -7.6 -164,520 Masonboro Island 1-22 39,293 -13.4 -0.4 -0.2 -8,557 1.9 76,400 0.7 26,529 -2.3 -92,283 -2.3 -89,198 Freeman Park 5-10 5,510 5.9 16.3 4.1 22,605 -0.8 -4,313 -10.0 -54,947 -9.3 -51,470 -10.3 -56,938 Carolina Beach 1-23 18,089 -8.5 -11.8 -1.7 -31,444 -3.9 -71,289 -6.6 -119,323 -9.3 -168,707 -10.8 -194,876 Kure Beach 1-21 15,342 -4.5 -10.3 -0.5 -7,650 -3.0 -46,331 -5.3 -82,055 -7.4 -113,295 -3.5 -54,197 Fort Fisher 1-19 16,799 0.2 3.4 2.2 36,410 2.2 37,301 -0.9 -14,971 3.8 63,608 24.6 413,523 Overall Summary – Annual Volume Change MIRP: Overall Volume Losses Significant Volume Losses Due To Equilibration Of The MIRP, Equating to ≈60% of Project Placement. Some Losses Captured North Of Placement Area. Wrightsville Beach: Overall Volume Losses Significant Volume Losses In WB – Central Due To Equilibration of 2024 CSRM Project, Equating to 32% of Project Placement. Some Losses Captured in WB – North/Mason Inlet and Wrightsville Beach – South. Masonboro Island: Overall Volume Gains Minor Volume Gains Above -14 ft NAVD88. However, Minor Volume Losses Experienced Above Depth of Closure. 53 Summary of Findings 2024 vs. 2025 (Total Change)Transects Reach Length avg shoreline change @ +5 ft NAVD88 avg shoreline change @ +1.4 ft NAVD88 avg volume change above +1.4 ft NAVD88 cumulative volume change above +1.4 ft NAVD88 avg volume change above -4 ft NAVD88 cumulative volume change above -4 ft NAVD88 avg volume change above -14 ft NAVD88 cumulative volume change above -14 ft NAVD88 avg volume change above -20 ft NAVD88 cumulative volume change above -20 ft NAVD88 avg volume change above -30 ft NAVD88 cumulative volume change above -30 ft NAVD88 Reach # ft ft ft cy/ft cy cy/ft cy cy/ft cy cy/ft cy cy/ft cy Mason Inlet Relocation Project 1-14 11,500 -54.8 -35.1 -4.0 -46,087 -12.6 -144,917 -23.8 -273,597 -21.9 -251,324 -21.1 -242,360 Wrightsville Beach* 1-24 21,703 -35.9 -31.5 -6.8 -147,225 -10.9 -236,678 -10.6 -229,474 -9.2 -199,264 -7.6 -164,520 Masonboro Island 1-22 39,293 -13.4 -0.4 -0.2 -8,557 1.9 76,400 0.7 26,529 -2.3 -92,283 -2.3 -89,198 Freeman Park 5-10 5,510 5.9 16.3 4.1 22,605 -0.8 -4,313 -10.0 -54,947 -9.3 -51,470 -10.3 -56,938 Carolina Beach 1-23 18,089 -8.5 -11.8 -1.7 -31,444 -3.9 -71,289 -6.6 -119,323 -9.3 -168,707 -10.8 -194,876 Kure Beach 1-21 15,342 -4.5 -10.3 -0.5 -7,650 -3.0 -46,331 -5.3 -82,055 -7.4 -113,295 -3.5 -54,197 Fort Fisher 1-19 16,799 0.2 3.4 2.2 36,410 2.2 37,301 -0.9 -14,971 3.8 63,608 24.6 413,523 Overall Summary – Annual Volume Change Freeman Park: Overall Volume Losses Moderate Volume Losses Above -14 ft NAVD88, Continuing Out to Depth Of Closure Carolina Beach: Overall Volume Losses Continued Erosion Of The 2022 CSRM Project With Losses Equivalent To 11% Of Project Placement. Total Losses Since 2022 Equate To ≈63% Of Placement. Kure Beach: Overall Volume Losses Continued Erosion Of The 2022 CSRM Project With Losses Equivalent To 11% Of Project Placement. Total Losses Since 2022 Equate To ≈67% Of Placement. Fort Fisher: Overall Volume Losses Minor Volume Losses Above -14, Significant Volume Gains Above -30 ft NAVD88 54 Summary of Findings Reach Length (ft) Volume Placed (cy) (2005/2006- 2025) Volume Change (cy) (2005/2006- 2025) Avergage Annual Erosion (cy/yr) Avergage Annual Erosion Rate (cy/ft/yr) (w/ management ) Background Erosion (cy) (2005/2006- 2025) Average Annual Background Erosion (cy/yr) Average Annual Background Erosion Rate (cy/ft/yr) (w/o management ) Wrightsville Beach-North/Mason Inlet 5,631 0 -116,390 -5,820 -1.0 -116,390 -5,820 -1.0 Wrightsville Beach-Central 9,923 3,689,524 271,195 13,560 1.4 -3,418,329 -170,916 -17.2 Wrightsville Beach-South 6,149 0 -216,155 -10,808 -1.8 -216,155 -10,808 -1.8 Wrightsville Beach 21,703 3,689,524 -61,349 -3,067 -0.1 -3,750,873 -187,544 -8.6 Masonboro Island-North 10,002 0 140,044 7,002 0.7 140,044 7,002 0.7 Masonboro Island-Central 11,653 582,207 -532,598 -26,630 -2.3 -1,114,805 -55,740 -4.8 Masonboro Island-South 17,638 174,778 -293,688 -14,684 -0.8 -468,466 -23,423 -1.3 Masonboro Island 39,293 756,985 -686,242 -34,312 -0.9 -1,443,227 -72,161 -1.8 Freeman Park (Oceanfront) 5,510 254,000 -1,016,554 -53,503 -9.7 -1,270,554 -66,871 -12.1 Carolina Beach-North 2,838 815,122 -85,417 -4,496 -1.6 -900,539 -47,397 -16.7 Carolina Beach-Central 8,248 3,706,747 289,038 15,213 1.8 -3,417,709 -179,879 -21.8 Carolina Beach-South 7,003 1,580,931 439,269 23,119 3.3 -1,141,662 -60,087 -8.6 Carolina Beach 18,089 6,102,800 642,890 33,836 1.9 -5,459,910 -287,364 -15.9 Kure Beach-North 6,017 1,001,562 199,436 10,497 1.7 -802,126 -42,217 -7.0 Kure Beach-Central 3,731 261,572 110,650 5,824 1.6 -150,922 -7,943 -2.1 Kure Beach- South 5,594 1,552,616 -126,549 -6,660 -1.2 -1,679,165 -88,377 -15.8 Kure Beach 15,342 2,815,749 183,536 9,660 0.6 -2,632,213 -138,538 -9.0 Fort Fisher-North 2,461 0 7,902 416 0.2 7,902 416 0.2 Fort Fisher-Central 8,842 0 519,839 27,360 3.1 519,839 27,360 3.1 Fort Fisher-South 5,496 0 168,257 8,856 1.6 168,257 8,856 1.6 Fort Fisher 16,799 0 695,998 36,631 2.2 695,998 36,631 2.2 Total 116,736 13,619,058 -241,721 -10,755 -0.1 -13,860,779 -715,846 -6.1 Background Erosion Rate Calculate Volume Change Above -14.0 ft NAVD88 From 2005/2006 - 2025 Subtract Out Placement Volumes From 2005/2006 – 2025 Annualized Background Erosion Rate = -6.1 cy/ft/yr for NHC 55 Summary of Findings CSRM Projects Are Essential For Maintaining Beaches Target is 0 Volume Losses = Volume Placement Nourishment Triggers Proactive Approach to Start the Process of Planning for and Optimizing Future Nourishments Projects if Federal Funds were to ever NOT come to Fruition. The Concept Of Nourishment Triggers Aims to Provide Equal Protection to all Parts of the Beach Modeled Cross-Shore Transport for Various Return Period Storms (i.e. 2-yr, 5-yr, 10-yr, 25-yr, 50-yr, & 100-yr) Using SBEACH Determined the Existing “Level of Protection” for the Beach What is the Largest Return Period Storm the Beach can Withstand? Determine Design Level of Protection What Level Storm do we want to Ensure Protection Against for the Entire Beach? Developed Nourishment Triggers Based on Design Level of Protection Volume of Sand Required from the First Row of Structures out to -14 ft NAVD88 to Protect Against the Design Level of Protection 56 Summary of Findings Nourishment Triggers Wrightsville Beach – Existing Level of Protection 57 Summary of Findings Representative Transect Shoreline Reach 10-yr Trigger Volume (cy/ft) Average Trigger Volume (cy/ft) WB-04 Wrightsville Beach - North/Mason Inlet 390 390 WB-09 286 WB-11 311 WB-14 295 WB-16 278 WB-20 Wrightsville Beach - South 347 347 Wrightsville Beach - Central 294 Wrightsville Beach – Design 10 YR Level of Protection Representative Transect Existing Conditions Level of Protection WB-04 50-yr WB-09 5-yr WB-11 25-yr WB-14 2-yr WB-16 10-yr WB-20 25-yr 0 20 40 60 80 100 120 140 160 180 200 220 240 260 280 300 320 340 360 380 400 420 440 460 480 500 520 540 560 580 600 WB - North/Mason Inlet 1-7WB - Central 8-17WB - South 18-24 Vo l u m e A b o v e - 1 4 f t N A V D 8 8 ( c y / f t ) WRIGHTSVILLE BEACH - NOURISHMENT TRIGGERS (10-Yr Level of Protection) 2025 2024 2023 2022 2021 2020 2019 2018 2017 2016 2015 2014 347 cy/ft 294 cy/ft 390 cy/ft 2014 2015 2016 2017 2018 2019 2020 2021 2022 2023 2024 2025 Nourishment Triggers Wrightsville Beach – Volume Status 58 Summary of Findings Nourishment Triggers Carolina Beach – Existing Level of Protection 59 Summary of Findings Carolina Beach – Design 25 YR Level of Protection Representative Transect Existing Conditions Level of Protection CB-05 25 CB-07 25 CB-11 25 CB-14 50 CB-19 100 CB-21 50 CB-22 25 Representative Transect Shoreline Reach 25-yr Trigger Volume (cy/ft) Weighted Trigger Volume (cy/ft) CB-05 Carolina Beach – North NA NA CB-07 293 293 CB-11 345 CB-14 314 CB-19 276 CB-21 263 CB-22 297 Carolina Beach - Central Carolina Beach - South 331 278 0 20 40 60 80 100 120 140 160 180 200 220 240 260 280 300 320 340 360 380 400 420 440 460 480 CB - North 1-5CB - Central 6-8CB - Central 9-16CB - South 17-23 Vo l u m e A b o v e - 1 4 f t N A V D 8 8 ( c y / f t ) CAROLINA BEACH - NOURISHMENT TRIGGERS (25-Yr Level of Protection) 2025 2024 2023 2022 2021 2020 2019 2018 2017 2016 2015 2014 278 cy/ft 331 cy/ft 293 cy/ft 2014 2015 2016 2017 2018 2019 2020 2021 2022 2023 2024 2025 Nourishment Triggers Carolina Beach – Volume Status 60 Summary of Findings Nourishment Triggers Kure Beach – Existing Level of Protection 61 Summary of Findings Kure Beach – Design 25 YR Level of Protection Representative Transect Existing Conditions Level of Protection KB-03 25-yr KB-05 100-yr KB-09 50-yr KB-11 25-yr KB-15 25-yr KB-18 5-yr KB-20 5-yr Representative Transect Shoreline Reach 25-yr Trigger Volume (cy/ft) Weighted Trigger Volume (cy/ft) KB-03 254 KB-05 270 KB-09 Kure Beach – Central 285 285 KB-11 305 KB-15 266 KB-18 NA NA KB-20 NA NA Kure Beach – North 260 Kure Beach – South 281 Nourishment Triggers Kure Beach – Volume Status 62 Summary of Findings 0 20 40 60 80 100 120 140 160 180 200 220 240 260 280 300 320 340 360 380 400 420 KB - North 1-6KB - Central 7-10KB - South 11-17KB - South 18-21 Vo l u m e A b o v e - 1 4 f t N A V D 8 8 ( c y / f t ) KURE BEACH - NOURISHMENT TRIGGERS (25-Yr Level of Protection) 2025 2024 2023 2022 2021 2020 2019 2018 2017 2016 2015 2014 281 cy/ft 285 cy/ft 260 cy/ft 2014 2015 2016 2017 2018 2019 2020 2021 2022 2023 2024 2025 Future Datasets Will Improve Analyses Assessment Of Background Erosion Rates With Respect To Maintenance Volumes And Cycles Assessment Of Specific Sand Placement Locations And Volumes Assessment of Beach Conditions With Respect to Nourishment Triggers Establishment Of Long-Term Trends Project Performance Natural Erosion/Accretion Patterns Determination Of Longshore Extent Of Inlet Influences Refinement Of Hotspot & Nodal Point Locations Assessment Of Borrow Area Volumes Throughout Nourishment Cycle Annual Monitoring Works In Conjunction With Coastal Modeling Provides Data For Model Calibration (Shorelines, Bathymetry, etc.) Provides Current Conditions From Which To Assess Alternatives 63 Summary of Findings – Final Thoughts Data Collection Survey Transects Survey Equipment Project Methodology Shoreline Change Volume Change Key Events: June 2024 – May 2025 Storm Activity Maintenance Activity Summary of Findings Shoreline & Volume Change (2024 - 2025) Inlet Conditions (2024 - 2025) Background Erosion Rates (2005/2006 - 2025) Nourishment Triggers (2014 - 2025) Q&A/Discussion 64 Presentation Outline 65 Q&A / Discussion