Assessing the effects of exploration causeway "Bravo" on Lake Carey, Western Australia, with options for risk mitigation during flood events

Kuiper, Juliette (2021) Assessing the effects of exploration causeway "Bravo" on Lake Carey, Western Australia, with options for risk mitigation during flood events. Honours thesis, Murdoch University.

Abstract

This Honours Industry Thesis identifies short- and long-term options on how to improve and restore the flow of Lake Carey, a salt lake in Western Australia, post-causeway construction. With major flood events occurring every 5-10 years and exploration Causeway Bravo built post the 2017 floods, options to mitigate the risk in case of flood events and to look at preventative management opportunities for construction of future causeways is critical. Obstruction of water flow, reduction in biodiversity and change in water quality are some of the major implications seen with causeways.

This thesis adopts a systematic approach of data collection to establish the cause-and-effect relationship between policy, regulations, dewatering discharge in proximity of causeways and flood risks. This data is contributing in the first steps towards the under-researched topic of exploration causeways and flood-risk mitigation in the mining industry of Western Australia.

The four objectives are as follows:

• Analyse the risks involved with flood events and hypersaline dewatering discharge onto Lake Carey.
• Collect data on Causeway Bravo and similar case studies and determine gaps in available data.
• Identify and assess short- and long-term options for flood risk mitigation for Causeway Bravo.
• Provide suggestions for the path forward.
The adopted methodology commenced with a dewatering risk assessment to determine the original status of the lake and the characteristics of the dewatering discharge. Data collection on five case studies, including a high-level study on Causeway Bravo, has been conducted to identify the key characteristics per causeway, such as length, number, and type of culvert sections. The other case studies include:

• Causeway D, Lake Carey, WA
• Bindah Causeway, Lake Carey, WA
• Main Causeway, Lake Lefroy, WA
• Railroad Causeway in the Great Salt Lake, Utah, USA.

Based on the collected data, four short-term options were identified and three long-term options. A multi-criteria assessment was then conducted with Gold Fields Australia which identified a hydrological assessment to identify lake flows, inflows and its bathymetry as the preferred short-term option and a main breach as the long-term option.

Item Type:	Thesis (Honours)
Murdoch Affiliation(s):	School of Engineering and Energy
Supervisor(s):	Rupf, Gloria and Meacher, C.
URI:	http://researchrepository.murdoch.edu.au/id/eprint/63757

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