BEACH AND INLET PROJECTS UPDATE

Transcription

1 BEACH AND INLET PROJECTS UPDATE

2 USACE DELTA PROJECT

3 USACE Delta Project Project Extents

4 Elevation Elevation (ft NAVD88) (ft NAVD88) USACE Delta Project Project Cross-Section ft 120 ft Post-Matthew Post-Matthew Profile Profile 85 ft 110 ft Pre- Project Pre- Project MHW MHW Station Station Post- Project Post- Project MHW MHW Beach Fill Beach Template Fill Berm Template Only Mean High Water Mean High Water Ocean Ocean Sta Berm cy/ft ~40-55 cy/ft -18 Sta Distance to Baseline (ft)

5 USACE Delta Project Project Extents

6 USACE Delta Project Original Project Plan USACE plan showed a ~ ft berm from Town line to SE 63 rd street Base project is from Town line to SE 77 th (4,000 ) = 163,345 CY shown on plans Delta project is from SE 77 th to SE 58 th (6,000 ) = 251,526 CY Both have ~ cy/ft placement rate Unit rate for Delta work = $11.93/cy Town has allotted up to $3 million for this project Project was completed in summer Received pre- and post-project surveys in December

7 USACE Delta Project Project Results USACE showed a ~ ft berm from Town line to SE 63 rd street project was actually constructed to SE 58 th street as originally planned and with a 150 ft berm Base project is from Town line to SE 77 th (4,000 ) = 163,345 CY shown on plans 246,245 CY placed Delta project is from SE 77 th to SE 58 th (6,000 ) = 251,526 CY shown on plans 394,010 CY placed Unit rate for Delta work = $11.93/cy - $7.61/CY actual Total volume placed from Town line to SE 58 th street = 640,255 cy

8 USACE Delta Project Project Results

9 LOCKWOODS FOLLY PROJECTS - SDI-5 PERMIT - AIWW CROSSING - NEARSHORE PLACEMENT

10 Lockwoods Folly Projects

11 Hotspot Location

12 Hot Spot Shoreline Change and Dune Escarpment Feb 2018 Jun 2018 MHW Structure Mar 2015 (BD) Mar 2015 (AD) Feb 2018 Jun 2018

13 Lockwoods Folly Inlet Projects - SDI-5 Permit O Brien and Gere Have Been Working to Get This Permit for the Town Allows Town to complete projects like the USACE to currently permitted widths and depths for just the inlet itself Timeline for approval is now late January

14 Lockwoods Folly Inlet Projects - AIWW Crossing Project USACE Released a Plan Set In Early Fall That Showed Placing 88,000 CY of Material on West End Of Oak Island Placement on Oak Island due to lower number of easements required Moved western edge of placement area further east Contract has been awarded and USACE is awaiting final schedule before determining if Town can pay for additional material to be dredged out of bend widener and placed (bid showed $7.50/cy) Town of Holden Beach has requested as well so meeting will take place to discuss options if schedule allows for additional material to be dredged Special meeting may need to be called for Town to approve additional monies if additional material can be dredged/placed

15 Lockwoods Folly Inlet Projects - AIWW Crossing Project

16 Lockwoods Folly Projects Nearshore Placement Town Has Asked that Next Project Be Placed Near West End Hotspot Currently Estimated ~30,000 CY - $95,000 Town Share Channel to be dredged to -10 deep and 150 wide Total cost = $676,000 = 30 days of dredging Most of funding from State Shallow Draft Fund Material will be placed in nearshore area near historical hotspot Will also complete additional survey monitoring in future to track offshore feature and hotspot behavior

17 Lockwoods Folly Projects Nearshore Placement

18 Lockwoods Folly Projects Nearshore Placement

19 Lockwoods Folly Project Nearshore Placement

20 Lockwoods Folly Projects Nearshore Placement USACE Is Current Showing Limited Availability for Special Purpose Hopper Dredges Next Year Next few projects will likely be completed with sidecaster dredge at Federal expense Town and County has reminded USACE that local funds were provided contingent on beneficial placement of the material in the nearshore

21 DUNE MONITORING PROJECT

22 Dune Monitoring Project Bi-Weekly Monitoring May 15 August 31, 2018 Color, Temperature and Grain Size Monitoring

23 Dune Monitoring Project- Temperature Results Measurements set up to record hourly Temperature that produces 50% of each gender is 84.6 f Gender determined in middle third of incubation Average Min Temperature - Dune Stations: 74.1 F - Control Stations: 74.1 F Average Temperature - Dune Stations: 84.0 F - Control Stations: 83.0 F Average Max Temperature - Dune Stations: 89.9 F - Control Stations: 88.0 F

24 Dune Monitoring Project - Color Results Color improved when contractor changed where borrowing material from in pit CONTROL STATIONS OBSERVATION STATIONS Date Caswell Beach 5 th PL West 54 th PL West 51 st PL W 42 nd PL W 23 rd PL W 13 th PL W 3 rd PL E 11 th PL E 29 th PL E 37 th PL E 46 th ST SE 55 th ST SE Weather 5/14/2018 7/1 7/1 7/1 3/4 4/3 3/4 4/3 4/3 5/1 3/4 3/6 3/6 3/6 Sunny 5/21/2018 7/1 7/1 7/2 5/1 4/1 4/1 4/2 5/1 4/1 4/3 3/4 4/3 4/2 Sunny 6/5/2018 7/1 7/1 7/1 4/1 5/2 3/3 5/2 5/1 4/1 4/4 3/4 3/3 4/4 Sunny 6/21/2018 7/1 6/2 6/1 4/2 4/1 4/2 3/2 4/2 4/2 4/3 4/4 3/4 4/3 Sunny 7/3/2018 7/1 8/1 7/1 4/1 5/1 5/2 4/2 5/1 6/1 4/4 6/1 3/3 3/4 Sunny 7/20/2018 7/1 7/1 7/1 4/1 5/1 3/4 4/3 5/2 4/1 3/3 3/6 4/4 3/4 Wet Sand 8/9/2018 7/1 5/1 7/1 5/1 5/1 4/1 4/1 4/1 5/1 4/1 4/2 4/3 4/2 Sunny 8/24/2018 7/1 7/1 6/1 4/2 4/2 4/2 4/3 4/3 4/2 4/4 4/4 4/3 5/2 Sunny 9/11/2018 7/1 7/1 7/1 7/1 5/1 5/2 4/2 4/2 5/1 3/3 4/4 3/4 5/2 Sunny

25 Dune Monitoring Project Grain Size Results Material met sediment grain size compatibility rules

26 Dune Monitoring Project Overall Results Final report was submitted to agencies October 1, 2018 with no comments received Temperatures recorded in dune stations were slightly warmer (approximately 1 degree avg) than control stations Most dune stations were installed on leeward side of dune crest which would be expected to be warmer Munsell color values were lower for non-nourished areas color improved when contractor moved Sediment grain size is compatible All nests laid in the dune restoration project area were relocated this year (11 of 51 nests laid 46 false crawls with 17 in dune restoration area)

27 ANNUAL MONITORING SURVEY (BEFORE FLORENCE)

28 Annual Monitoring Survey ( ) Completed just before Hurricane Florence arrived in early September Survey consists of: Beach profiles Eastern Channel Lockwoods Folly Inlet

29 Annual Monitoring Survey ( )

30 Annual Monitoring Survey ( ) Beach Profile Shoreline and Volume Change Results

31 Annual Monitoring Survey ( ) Volume Change

32 Annual Monitoring Survey ( ) Example Profiles

33 Annual Monitoring Survey ( ) Eastern Channel Results

34 Annual Monitoring Survey ( ) Lockwoods Folly Inlet Results Some movement of inlet throat to east Some deepening/straightening of inlet over bar

35 POST-FLORENCE MONITORING SURVEY

36 Post-Florence Monitoring Survey Elevated Water Levels and Wave Conditions ~3 Days

37 Post-Florence Monitoring Survey Elevated Water Levels and Wave Conditions ~3 Days ~3 Days

38 Post-Florence Monitoring Survey Beach Profile Shoreline and Volume Change Results After initial meeting with FEMA, appears that Town may qualify for emergency dune restoration project Will hopefully know something this Spring

39 Post-Florence Monitoring Survey Volume Change

40 Post-Florence Monitoring Survey Example Profiles

41 Post-Florence Monitoring Survey Example Profiles

42 Post-Florence Monitoring Survey Example Profiles Berm Loss Captured Offshore

43 Post-Florence Monitoring Survey Eastern Channel Results Shoaled Volume (cy) Date Range Beach Compatible Non Beach Compatible Combined Reach 1 Reach 2 Reach 3 Total Reach 4 Reach 5 Total Total Sep Oct ,230 1, ,650 2,182 4,103 Template - Oct ,883 4,318 15, , ,238

44 Post-Florence Monitoring Survey Lockwoods Folly Inlet Results Some minor shoaling within inlet over outer bar 0-2 where shoaling occurred September 2018 October 2018

45 FEMA TURTLE HABITAT PROJECT

46 FEMA Turtle Habitat Restoration Project Initial Project Budget for Volume of 364,000 cy FEMA authorization of $ 6,026,365 (75% of Cost) State/Town expected contribution of $ 2,008,788 Total project expected cost = $ 8,035,153 Additional Town Funds (Possible) Contribute $5 7 million: 435, ,000 cy Total potential project volume: 750,000-1,000,000 cy May also incorporate Post-Florence project volume depending on FEMA approval and reimbursement timeline

47 FEMA Turtle Habitat Restoration Project Project Extent Alternatives

48 FEMA Turtle Habitat Restoration Project Turtle Habitat Restoration ONLY Turtle Habitat: 20 ft wide dune at 10 ft NAVD88 with 70 ft berm at 7 ft NAVD88 14,000 ft (Sta ) Template Volume Required: 470,000 cy Turtle Habitat Restoration with Additional Town Volume Alternative A: 20 ft wide dune at 15 ft NAVD88 with 50 ft berm at 7 ft NAVD88 18,000 ft (Sta ) Template Volume Required: 1,408,000 cy Alternative B: 20 ft wide dune at 12 ft NAVD88 with 50 ft berm at 7 ft NAVD88 27,000 ft (Sta ) Template Volume Required: 1,404,000 cy

49 FEMA Turtle Habitat Restoration Project

50 FEMA Turtle Habitat Restoration Project Offshore Site #1 Preliminary volume estimate in permitted central reach borrow area: 400, ,000 cy Distance from project: maximum 5 mi Hopper dredge project Field investigations: Jan/Feb 19 Cultural Resource Survey: Magnetometer and Side- Scan (Geodynamics and Tidewater Atlantic Research) Central Reach Vibracoring (American Vibracore Services)

51 FEMA Turtle Habitat Restoration Project Offshore Site #1 Example Vibracores

52 FEMA Turtle Habitat Restoration Project Proposed Fee and Schedule Proposed Schedule 16 Months Finalize Construction by May 2020 Field investigations next 3 months Preliminary engineering and permitting next 3-9 months Final design and bidding next 9-12 months Project construction next months

53 MASTER PLAN

54 Overview of Master Plan Purpose and Need To Establish and Implement a Comprehensive, Long-Term, Non- Federal Beach and Inlet Management Program that will Restore and Maintain the Oceanfront Shoreline Of Oak Island. Provide Shore Protection for Residential Structures, Infrastructure, and Recreational Assets; and Preserve the Local Tourism-Based Economy. Consolidate the Shore Protection Planning and Management Activities of the Town Under a Unified, Regional Beach and Inlet Management Program.

55 Overview of Master Plan Verify Sediment Need for Initial Project and Over Next 50 Years (2-3 Mcy for Initial Project / 1 Mcy Every 6 Years = Mcy Preliminary Estimate No Storms) USACE Delta and FEMA Turtle Habitat Project Can Hopefully Reduce Volume Need May Need to Build In Phases Modeling to Refine Above Estimates Currently Ongoing

56 Overview of Master Plan Field Investigations Geotechnical vibracoring for sediment compatibility November 2018 vibracores Eastern Channel, LFI, AIWW bend widener Jan-Mar 2019 native sampling and vibracoring upland sites Additional offshore work planned for January- March central reach Other offshore areas and Frying Pan Shoals to be completed later - BOEM

57 Overview of Master Plan Lockwoods Folly Inlet Management Plan Analytical Analysis Digitize inlet throat and shoreline locations Look for patterns to determine safe corridor Cultural resources are a major constraint Modeling Field velocity studies of Lockwoods Folly Inlet for models late Jan/early February Test options to verify analytical results

58 Overview Summary USACE Delta Project - Completed Lockwoods Folly Inlet Initatives SDI-5 Permit Complete By February 2019 AIWW Crossing with Beach Placement Complete by May 2019 Nearshore Placement Complete Last Half of 2019 Dune Monitoring Report Complete Annual and Post-Florence Surveys Annual Survey - Completed Post-Florence Survey Complete by February 2019 FEMA Request for Post-Florence Reimbursement Discussions with FEMA Complete by Spring 2019

59 Overview Summary FEMA Turtle Habitat Project Field Investigations - Complete by March 2019 Engineering and Permitting Submittals - Complete by May 2019 Receive Permits and Finalize Construction Documents Complete by October 2019 Bid Project November 2019 Project Construction January May 2020 Master Plan Field Investigations Ongoing Discussions with BOEM and Others Concerning Frying Pan Shoals Estimate of Engineered Beach Volume Need Complete by Spring/Summer 2019 Environmental Studies and Documentation - Ongoing

60 Overview Summary