1. Environmental Design of Cottesloe Rock Swimming Pool Final Year Project Presentation Date: 16th October Luan Nguyen Presenter, School of Civil and Resource Engineering, the University of Western Australia Jorg Imberger & Clelia Marti Supervisors, Centre for Water Research

2. Motivation
Purpose of Research
Design of the environmental parameters of a low maintenance/maintenance-free rock swimming pool, constructed as an extension of the existing groyne.
Conduct structural design and feasibility study of the placement of the structure (to be done by Dan Courtney).
A facility for public usage as a mean for safe swimming, disability access and recreational activities.
To reflect the rich culture of Cottesloe and the history of the beach.

3. Study Domain Area of Research SOURCE: Google Maps & Google Earth 500 m

4. Current Proposal Conceptual Design for the current proposal AFTER
75m
25m
AFTER
BEFORE
SOURCE: nearmap.com

5. Objective
Goals of Research
Determine environmental and cultural impacts of the placement of the Cottesloe Rock Swimming Pool by delivering environmental parameters of the system as inputs for structural design and public engagement techniques.

6. Approach
Research Methodology

7. Wave Model - SWAN Description of model
Wave breaking, bottom friction, reflection, diffraction, refraction and triad
Validation: Cottesloe Wave Station
Outputs: Significant wave height, period and direction
Cottesloe Domain
Cottesloe Domain
SWAN
Wind Field
Weather Forecast and Research Model (WRF)
Wind Field
Perth Coastal Margin SWAN
Nesting Spectrum
Field Data from Carnac Wave Logger
SOURCE: Google Earth

8. Wave Model - SWAN Control Case Modified Case Pool’s wall added
Submerged reef near tip of groyne to ensure high waves near tip of groyne
Grid size: 5 x 5 m uniform grid
Quadruplets turned off due to shallow water
Model groyne as obstacle
Size: 550 x 1010
SOURCE: ARMS

9. Hydrodynamics Model - ELCOM
Modified Case
Control Case
Plaid grid size with 50 m coarse grid and 5m fine grid
Wave forcing from CWR’s Perth Coastal Margin Model
Wind data from CWR’s Lake Diagnostic System
Default coefficients as given in user manual
Size: 500 x 1000
Pool’s wall added
Submerged reef near tip of groyne to ensure high waves near tip of groyne
SOURCE: ARMS

10. ELCOM Tracers 4 4 3 3 2 2 1 1 5 5 6 6
SOURCE: ARMS & Google Earth

11. CWR’s Cottesloe Wave Logger
Description of Validation Tool
Installed at the corner of SWAN’s domain
Record 15-minute intervals of wave height, period and direction
Use as a validation tool for the model

12. CWR’s Cottesloe Wave Logger
Example of Outputs

13. RESULTS AND DISCUSSION

14. SWAN Results Discussion of SWAN Outputs – Significant Wave Height
Control Case
Modified Case
SOURCE: ARMS

15. SWAN Results
Comparison of the two cases
SOURCE: ARMS

16. SWAN Results Comparison of the two cases
Higher waves within submerged reef region
Comparison of the two cases
SOURCE: ARMS

17. SWAN Results Comparison of the two cases
Higher waves within submerged reef region
Comparison of the two cases
Higher waves near pool wall
SOURCE: ARMS

18. SWAN Results Comparison of the two cases
Similar wave conditions nearshore
Comparison of the two cases
SOURCE: ARMS

19. SWAN Results
Wave near pool edge
SOURCE: ARMS

20. SWAN Results Phase Differences between High and Low Water1 2
η= H 2 sin⁡(𝑘𝑥−𝜔𝑡)
𝑘= 2𝜋 𝐿
𝜔= 2𝜋 𝑇
Graph generated by Matlab

21. SWAN Results
Data Validation
SOURCE: ARMS

22. SWAN Results Discussion of SWAN Outputs – Mean Wave Period
Control Case
Modified Case
SOURCE: ARMS

23. ELCOM Results
Example of Tracer Outputs

24. ELCOM Results
Example of Speed Outputs
SOURCE: ARMS

25. Conclusion
Higher waves are experienced near the tip of the groyne and submerged reef area due to depth-induced breaking
Higher waves near tip of groyne and lower wave near side of pool can encourage flushing cycle of the water inside the structure
ELCOM results suggested there are changes in current velocity near the bed which can result in changing in shoreline

26. Recommendations
Continue SWAN realtime simulation for at least 6 months to gain enough data for years design period
Determine sedimentary transport rate using Shield’s parameter and current outputs from ELCOM
Preliminary geometric design can still be performed using available logger and model data

27. SWAN Wave Model www.rmso.com.au
Details of Realtime Model
Visit CWR’s Realtime Management System Online (RMSO)
Select to view Simulations
Select to view the Perth Coastal Margin
Select GROYNE for control case, POOL for modified case
Select wave parameter to be viewed

28. SWAN Wave Model Details of Realtime Model
Model located under Simulations
Model runs as nested domain in PCM
Select COT-GROYNE for Control Case, COT-POOL for modified case
Select variable to be viewed

29. Public Engagement Use as a tool for public engagement
Description of Website
Use as a tool for public engagement
To be used to educate, communicate to the main user groups in WA and as a space for the community to contribute inputs to the project
Still in development stage

30. Public Engagement
Description of Website

31. Acknowledgement I would like to say thanks to:
My supervisors Jorg and Clelia
Jorg’s personal assistants: Emilia and Laura T
Project initiator: Tom Locke
CWR’s staffs and field team
Special thanks to Lee and Leticia for modelling help
PhD students for providing technical assistance: Daniel, Christina, Mahmood, Bronwyn, Vahid
Fellow intern students: Linh, Laura B, Lee, Josh, Saba, Dan, Taylor, Melanie, Laurianne, Gwendelyn, Geraldine
My friends and family
My workplace
Project supporters including Professor Bloomfield

32. Questions?

33. CWR’s Cottesloe Wave Logger
Description of Wave Logger

34. CWR’s Cottesloe Wave Logger
Description of Wave Logger