North Carolina Regional Sediment Management

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2008 NCBIWA Annual Conference Shaping the Future
of Coastal North Carolina the Southeast
North Carolina Regional Sediment Management
Gregory L. Williams, Ph.D., P.E. Chief, Coastal,
Hydrology Hydraulics Section Wilmington
Regional Engineering Center
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Corps Program

• Project funded
• Programs (colors of money)
• Construction General (CG)
• General Investigation (GI)
• Operation Maintenance (OM)
• Regulatory
• Navigation project addresses navigationonly
• Coastal Storm Damage Reduction addresses
  CSDRonly
• Tension exists between programs, project types
  and funding authorities

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Cool Quote
The general impression of the application of
coastal management at the Local Authority is that
the more elevated and remote the expert writer is
on the subject, then the more precise his
predictions and the more black and white the
issues. The on-site engineer finds that the
issues always remain grey and that all his
predictions are fraught with high levels of
uncertainty and strong political and local
resident input. The Gold Coast experience to
date has been that there are no coastal
management/coastal protection panaceas and that
tactics and flexibility are much more important
than unattainable theoretical strategies. Each
section of coastline holds its own unique blend
of coastal process interactions perhaps the best
way to appreciate the local problems and hazard
is to actually live there and observe them
continuously in real time. A.W. (Sam)
Smith L.A. (Angus) Jackson Shore and
Beach July 1990
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USACE RSM ProgramObjective

• To improve sediment management practices within
  the Corps by demonstrating how to implement a
  system-based approach and how such an approach
  provides opportunities to achieve greater
  effectiveness and efficiency.

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Vision

• Sediment is a resource asset
• Understand the sediment systemNC/VA to NC/SC
• Institutionalize making right system decisions
• State line to state line

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NCs FY08 RSM Program

• Data mining/eCoastal
• Brunswick County
• Bogue Banks/MHC

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Data Mining

• eCoastal (Enterprise GIS)
• complete organizational approach to sharing,
  using, and managing spatial information
• developed for coastal engineering business
  practices
• developed by USACE utilizing spatial data
  standards (SDS)
• data management solution to provide information
  for planning and prediction of regional and local
  coastal processes
• Converted/uploaded approximately ½ of in-house
  survey data from 2000 Present
• Coastal tools implementation at District and
  State
• Heavily coordinated and prioritized with NC
  DCM/DWR
• Adopted by NC as coastal data management platform

http//ecoastal.usace.army.mil/index.asp
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Holden Beach
Oak Island
Ocean Isle Beach
Lockwoods Folly Inlet
Sunset Beach
Shallotte Inlet
Tubbs Inlet
Bald Head Island
Little River Inlet
Cape Fear
Brunswick County
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• Conceptual Sediment Budget
• Literature review
• Dredging history
• Nourishment history

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Detailed Sediment Budget

• Conceptual budget
• Spatial data analysis
• Shoreline change
• Profile analysis
• Shoaling/dredging records
• Coastal processes modeling
• 2000 to 2007 time period

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CASCADE

• Regional longshore transport and
• beach change model that incorporates
• Regional trends in offshore contours
• Multiple, interacting projects
• Inlet sediment storage and transfer
• Sources and sinks (beach nourishment, washover,
  breaching, wind-blown sand, cliff erosion, etc.)
• Jetty construction (impoundment, bypassing)
• Navigation channel maintenance
• Large-scale gradients in forcing long-term
  trends (e.g., relative sea level rise, increased
  storm frequency and intensity)

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CascadeConceptual Coverage
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Shallotte Inlet Ebb Shoal Recovery Rates
Model Validation
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Alternative 1 49.7M cy in 48 years, 3 inlets
(Lockwood Folly, Shallotte, Tubbs). Beach fill
distributed evenly over the planned locations.
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Alternative 1 49.7M cy in 48 years, 3 inlets
(Lockwood Folly, Shallotte, Tubbs). Beach fill
distributed evenly over the planned locations.

• Large beach accretion over Oak Island
• Severe erosion on the west side of Shallotte
  Inlet
• Depletion of the shoals at Shallotte and
  Lockwoods Folly inlets.
• Shallotte and Lockwoods Folly inlets cannot
  supply the sand required by the planned dredging
  schedule.

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Alternative 9-10 17.7M cy distributed among the
areas where most erosion occurs. The sand is
taken from the closest inlet. Alt 10 includes
initial construction.
There is a surplus of 3Mcy from SMP.
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Alternative 9-10 17.7M cy distributed among the
areas where most erosion occurs. The sand is
taken from the closest inlet. Alt 10 includes
initial construction.

• In these alternatives the ebb shoals are dredged
  on a 4 years schedule compared to the 6 years
  used previously.
• Shallotte ebb shoal is recovering and shows a
  stable progression in time.
• Lockwoods Folly Inlet is recovering well between
  dredging.
• Shoreline is similar to Alt 7-8 but with less
  accretion and slightly more erosion in the area
  of Holden Beach East.
• The recovery of the ebb shoal is slightly better
  for Alt 10

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Bogue Banks
Shackleford Banks
Beaufort Inlet MHC Harbor
Barden Inlet
Bogue Inlet
Cape Lookout
Bogue Banks/Morehead City
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MHC/Bogue Banks

• Existing data and analysis
• Leveraging with Bogue Banks shore protection,
  DMMP, MHC navigation project
• Sediment budgettransport pathways, volumes,
  losses, placement
• Cape Lookout/Barden Inlet to Bogue Inlet
• CASCADE model

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Barden Inlet
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RSM Budget

• FY08 590,000
• FY09 600,000 (Senate bill)
• FY10 ??
• Managed by ERDC Program Manager in the total RSM
  program

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FY09 RSM Plans

• Continued BIMP coordination
• Continued support to eCoastal GIS and remainder
  of hydro survey data7200 data sets
• Continue/complete MHC/Bogue Banks sediment
  budgets and CASCADE model
• WRDA Section 2037 support to State