beach and inlet projects update · – provide shore protection for residential structures,...

BEACH AND INLET PROJECTS

UPDATE

USACE “DELTA” PROJECT

USACE “Delta” Project

• Project Extents

• Project Cross-Section

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-8

-6

-4

-2

0

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-50 0 50 100 150 200 250 300 350 400 450 500 550 600 650 700 750 800

Elev

atio

n (

ft N

AV

D8

8)

Distance to Baseline (ft)

Station 220+00

220+00 (Post-Matthew) Berm Only-Mid (75ft) MHW

Post-Matthew

ProfileBeach Fill

Template

Berm Only

38.4 cy/ft

Ocean

Mean High Water

Sta 220+00

75 ft

Pre-

Project

MHW

Post-

Project

MHW

85 ft

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-18

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-10

-8

-6

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-2

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-50 0 50 100 150 200 250 300 350 400 450 500 550 600 650 700 750 800

Elev

atio

n (

ft N

AV

D8

8)

Distance to Baseline (ft)

Station 220+00

220+00 (Post-Matthew) Berm Only-Mid (75ft) MHW

Post-Matthew

ProfileBeach Fill

Template

Berm

~40-55 cy/ft

Ocean

Mean High Water

Sta 220+00

120 ft

Pre-

Project

MHW

Post-

Project

MHW

110 ft


• Project Extents


• Original Project Plan

– USACE plan showed a ~120-130 ft berm from Town line to SE 63rd

street

– Base project is from Town line to SE 77th (4,000’) = 163,345 CY

shown on plans

– Delta project is from SE 77th to SE 58th (6,000’) = 251,526 CY

– Both have ~ 40-55 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


• Project Results

– USACE showed a ~120-130 ft berm from Town line to SE 63rd street –

project was actually constructed to SE 58th street as originally

planned and with a 150 ft berm

– Base project is from Town line to SE 77th (4,000’) = 163,345 CY shown

on plans – 246,245 CY placed

– Delta project is from SE 77th to SE 58th (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 58th street =

640,255 cy


• Project Results


LOCKWOODS FOLLY PROJECTS

- SDI-5 PERMIT

- AIWW CROSSING

- NEARSHORE PLACEMENT

Lockwoods Folly Projects

Hotspot Location

Hot Spot Shoreline Change and Dune Escarpment

Feb 2018

Jun 2018

Feb 2018

Jun 2018

MHW

Mar 2015 (BD)

Mar 2015 (AD)

Structure

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

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

Lockwoods Folly Inlet Projects - AIWW Crossing Project

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

Lockwoods Folly Project – 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


DUNE MONITORING PROJECT

Dune Monitoring Project

• Bi-Weekly Monitoring May 15 – August 31, 2018

– Color, Temperature and Grain Size Monitoring

Dune Monitoring Project- Temperature Results

Average Max Temperature

- Dune Stations: 89.9 F

- Control Stations: 88.0 F

Average Temperature



• 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 Monitoring Project - Color Results

• Color improved when contractor changed where

borrowing material from in pit

Caswell Beach 5th PL West 54th PL West 51st PL W 42nd PL W 23rd PL W 13th PL W 3rd PL E 11th PL E 37th PL E 46th ST SE 55th ST SEWeather

5/14/2018 7/1 7/1 7/1 3/4 4/3 3/4 4/3 4/3 5/1 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 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 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 4/4 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 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 3/6 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 4/2 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 4/3 5/2 Sunny

9/11/2018 7/1 7/1 7/1 7/1 5/1 5/2 4/2 4/2 5/1 4/4 3/4 5/2 Sunny

4/4

CONTROL STATIONS OBSERVATION STATIONS

29th PL E

3/4

Date

3/3

4/4

4/1

3/3

4/3

4/4

4/3

Dune Monitoring Project – Grain Size Results

• Material met sediment grain size compatibility

rules

• 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)

Dune Monitoring Project – Overall Results

ANNUAL MONITORING SURVEY2017-2018 (BEFORE FLORENCE)

• Completed just before Hurricane Florence arrived in

early September

• Survey consists of:

– Beach profiles

– Eastern Channel

– Lockwoods Folly Inlet

Annual Monitoring Survey (2017-2018)

• Beach Profile Shoreline and Volume Change Results


Annual Monitoring Survey (2017-2018) – Volume Change

• Example Profiles


• Eastern Channel Results


• Lockwoods Folly Inlet Results

– Some movement of inlet throat to east

– Some deepening/straightening of inlet over bar


POST-FLORENCE MONITORING

SURVEY

• Elevated Water Levels and Wave Conditions

Post-Florence Monitoring Survey

~3 Days

• Elevated Water Levels and Wave Conditions


~3 Days

~3 Days

• 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


Post-Florence Monitoring Survey – Volume Change



Berm Loss

Captured Offshore

• Eastern Channel Results


Reach 1 Reach 2 Reach 3 Total Reach 4 Reach 5 Total

Sep 2018 - Oct 2018 237 454 1,230 1,921 532 1,650 2,182 4,103

Template - Oct 2018 88,883 4,318 15,692 108,894 128 217 345 109,238

Date Range

Shoaled Volume (cy)

Beach Compatible Non Beach Compatible Combined

Total

• Lockwoods Folly Inlet Results

– Some minor shoaling within inlet over outer bar

– 0-2’ where shoaling occurred

September 2018 October 2018


FEMA TURTLE HABITAT 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 – 609,000 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

FEMA Turtle Habitat Restoration Project


• Project Extent Alternatives


• 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. 300+00 – 430+00)

• 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. 300+00 – 470+00)

• 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. 300+00 – 560+00)

• Template Volume Required: 1,404,000 cy


Offshore Site #1• Preliminary volume

estimate in permitted central reach borrow area: 400,000 – 500,000 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)


Offshore Site #1 – Example Vibracores

• 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 12-16 months


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.

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 = 10-15 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


• 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


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


• 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

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

Overview Summary

Overview Summary