Coastal Lagoon Entrance Management - What can models tell us?

Wainwright, D., Baldock, T. and Callaghan, D. (2012). Coastal Lagoon Entrance Management - What can models tell us?. In: 21st NSW Coastal Conference: Papers. 21st NSW Coastal Conference, Kiama, NSW, Australia, (1-20). 6-9 November 2012.

Author Wainwright, D.
Baldock, T.
Callaghan, D.
Title of paper Coastal Lagoon Entrance Management - What can models tell us?
Conference name 21st NSW Coastal Conference
Conference location Kiama, NSW, Australia
Conference dates 6-9 November 2012
Proceedings title 21st NSW Coastal Conference: Papers
Place of Publication Australia
Publisher New South Wales Coastal Conference
Publication Year 2012
Sub-type Fully published paper
Open Access Status
Start page 1
End page 20
Total pages 20
Language eng
Abstract/Summary In New South Wales, low lying flooding around the fringes of intermittently open coastal lagoons (ICOLL’s) is commonly managed through artificial breaching. The plans which specify the water level at which manual breach operations occur are often governed by the degree to which the community will tolerate nuisance flooding. The actual mechanics of the manual breach operation (when, where, how) are typically informed by ‘gut’ feel, past experience and detailed field studies of selected lagoons, primarily undertaken in the 1970’s and 1980’s. Numerical modelling presents an opportunity to gain insight into the impact of broad scale policy decisions on the one hand, and the manual breach methods on the other. Recent research has aimed to improve the ability of available models, and two different models arising from that research are discussed here. Firstly, a method for long term statistical modelling of the “fill – spill – close” cycle is presented. A model built using that method has been repeatedly executed (5000 times) using random time series (110 years long) of waves and rainfall. Using this method, it was possible to simulate the impact that artificial opening practices and/or climate change will have on key parameters such as percentage time open, exceedance probabilities of berm heights and typical water levels. Secondly, improvements to the representation of complex breach hydraulics by numerical models are discussed and presented. Using an improved model, the impact of field operations on the effectiveness of proposed breach operations was investigated. Questions which the model can inform include: How does the location of a ‘pilot’ channel for breaching affect the speed with which a lagoon drains? Or, how does the ‘trigger’ level affect the final size of the breach? The models are demonstrated using real world data from Tabourie Lake.
Q-Index Code E1
Q-Index Status Provisional Code
Institutional Status UQ

Document type: Conference Paper
Collection: School of Civil Engineering Publications
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Created: Sat, 15 Mar 2014, 11:58:40 EST by David Wainwright on behalf of School of Civil Engineering