Shallow Water Wave Modelling

1
Government of Barbados Inter-American Development
Bank Coastal Infrastructure Programme Addressing
the Challenge of Coastal Erosion Prepared by
Baird and Associates and the Coastal Zone
Management Unit Presented by Dr. Leo
Brewster Director, CZMU
2
The Locations

• Rockley to Drill Hall
• Crane Beach
• Holetown Beach
• Welches Beach
• Womans Bay
• Holetown Lagoon
• Tent Bay
• Walkers Savannah

3
This Presentation will feature two of these
locations

• Welches Beach
• Rockley to Coconut Court

4
Permitting / Approvals Process
5
Welches Beach

• Project Objectives
• Minimize overtopping of roadway
• Expand beach if possible

6
Project Location
Welches beach is located at Welches in Christ
Church on the south side of Highway 7,
approximately 0.5 km west of Oistins.
7
Existing Conditions
8
The Problem
During high wave energy events, waves either
(1) run along the undercut sea cliff,
increasing in height as they move inshore at the
window to the sea at Cachel causing overtopping.

9
The Problem
(2) The second area susceptible to overtopping is
located at the east end of the Welches
Window-to-the-Sea. The seawall terminates
immediately west of the problem area (the blue
wall in the photo is located on the north side of
Highway 7).
10
ENVIRONMENTAL INVESTIGATIONS UNDERTAKEN

• Benthic Surveys
• Coastal Vegetation Surveys
• Marine Water Quality
• Turtle Nesting

11
SOCIAL IMPACT CONSIDERATIONS

• Stakeholder Meetings held pre, during and post
  construction
• Social survey undertaken post construction.

12
PROPOSED COMPONENTS OF PROJECT

• Construct segmented Groyne to East of Site
• 5500 Cubic Meters of Sand west of Eastern Groyne
• Construct Concrete Outlook
• Refurbish Existing Groyne and extend by 10m
• Construct 40m Groyne to West of Site
• 1500 Cubic Meters of Sand west of Eastern Groyne

13
Final Design Main Project
14
Project Summary

• Contract Award Price Bds. 2,590,830.00 VAT
  Inclusive
• Actual Construction Cost Bds. 2,772,093.99 VAT
  Inclusive
• Construction Time 10 months

15
Rockley to Coconut Court
Project Vision

• Create a signature project for the Coastal
  Infrastructure program that is defined by
• Best public/tourist access to the shoreline on
  the island
• Longest section of public walkway along the shore
• Together improving the appreciation for the
  Barbados coast

16
Rockley to Coconut Court
Project Objectives

• Create continuous walkway / access
• Expand beach where feasible
• Preserve and enhance natural environment

17
Rockley Beach Project Activities

• Physical Model Coastal Analyses
• Environmental Assessment
• Stakeholder Consultation
• Permit Applications
• Design
• Contract Documents
• Town Planning Approval
• IADB Washington Review
• Bidding and Approvals Process
• Construction and Construction Observation

18
Rockley to Hastings Physical Model
19
Selection of Headland/Beach

• Headland/Beach prevents loss in most conditions
• Beachfill only would experience rapid loss of
  sand and would not provide a reliable base for
  the walkway
• Breakwaters would prevent natural supply from
  offshore (and result in increased wave setup)

20
ENVIRONMENTAL INVESTIGATIONS UNDERTAKEN

• Benthic Surveys
• Coastal Vegetation Surveys
• Marine Water Quality
• Turtle Nesting

21
SOCIAL IMPACT CONSIDERATIONS

• Stakeholder Meetings held pre, during and post
  construction
• Social survey undertaken pre construction.

22
(No Transcript)
23
Project Summary

• Contract Award Price Bds. 18,398,830.00 VAT
  Inclusive
• Actual Construction Cost (to date) Bds.
  16,474,382.26 VAT Inclusive (Clean up and
  retention fee still outstanding)
• Construction Time 18 months

24
Coastal Infrastructure Project Benefits

• Quality Shoreline Infrastructure
• Greatly Improved Beaches and Public Access
  (Welches, Holetown and Rockley)
• Environmental Improvements (turtle nesting,
  water filtration)
• Generational Capacity (Quality, World Class,
  Maintained)

25
Project Benefits

• Protects Large Govt Investment
• Significant Long Term Cost Savings
• Maintains a Valuable Public Resource in excellent
  condition
• Maintains Safety of Facility