| Title: |
Laboratory Experiments into the Effect of Reef Width on Extreme Water Levels During Cyclone Events |
| Authors: |
Splinter, KD; Huo, M; Barthelemy, X; Blacka, M |
| Source: |
urn:ISBN:9781922107916 ; Australasian Coasts and Ports Conference, Cairns, Australia, 2017-06-21 - 2017-06-23 |
| Publication Year: |
2017 |
| Collection: |
UNSW Sydney (The University of New South Wales): UNSWorks |
| Description: |
Coral reefs provide protection from waves for coastal communities around much of the Pacific region. During modal wave conditions, incoming waves break on the fringing reef edge, such that waves within the reef are considered to be depth limited. During extreme weather events, such as Tropical Cyclones, waves break on the reef slope and dissipate their energy while propagating across the reef and lagoon. These more energetic wave conditions can lead to the generation of surf beat within the lagoon. Total water levels inside the reef are controlled by several phenomena, including wave dissipation, wave-setup, and low-frequency surf beat. The proportion that each contributes to the total water level is a function of location within the reef and the reef width itself. The focus of the study is the impact of reef width on the hydrodynamic processes occurring on fringing reefs. Wave flume modelling adopted an idealised reef profile from Avarua, Rarotonga in the Cook Islands, which has characteristics that are typical of reef profiles found within many Pacific Islands. The model was constructed in the 1.2 m wave flume at the Water Research Laboratory. Four reef widths were tested ranging from 75 m to 600 m. At each reef width, 2 water levels and 3 wave periods were selected to mimic a variety of storm conditions. Experimental results show that the mean wave set up, surf beat and maximum total water levels have complex non-monotonic behaviours for the chosen set of initial wave height, wave spectral peak frequency, still water level, and reef width conditions. Results suggest that narrower reef widths are more vulnerable to over-topping at the landward edge and experience higher total water levels within the reef when both incident and low-frequency components are considered in calculating extreme water levels (h1%). When only the low-frequency components (set-up and surf beat) are considered, 1% exceedance water levels (h1%SB) increase between reef widths of 75 and 300 m before dropping at 600 m. Reef widths ... |
| Document Type: |
conference object; report |
| File Description: |
application/pdf |
| Language: |
unknown |
| ISBN: |
978-1-922107-91-6; 1-922107-91-3 |
| Relation: |
https://search.informit.com.au/documentSummary;dn=932802250887944;res=IELENG; https://hdl.handle.net/1959.4/unsworks_50717; https://doi.org/10.26190/unsworks/26643 |
| DOI: |
10.26190/unsworks/26643 |
| Availability: |
https://hdl.handle.net/1959.4/unsworks_50717; https://unsworks.unsw.edu.au/bitstreams/af6f0df3-5755-426a-8b68-8d1a83b94e32/download; https://doi.org/10.26190/unsworks/26643 |
| Rights: |
open access ; https://purl.org/coar/access_right/c_abf2 ; CC-BY-NC-ND ; https://creativecommons.org/licenses/by-nc-nd/4.0/ ; free_to_read |
| Accession Number: |
edsbas.8C58520B |
| Database: |
BASE |