A recent delegation visit to Australia by the Royal Irrigation Department (RID) of Thailand provided an opportunity for knowledge exchange and exploration of effective water management strategies. Lead by the Director General of RID, the delegation consisted of various representatives from different levels and sections within the organisation. The focus of the visit centred around flood management and associated infrastructure, with particular interest in the management of Warragamba Dam in Sydney. Additionally, discussions touched upon water quality monitoring, stakeholder engagement, and the importance of ecological considerations in water management.
Warragamba Dam – Ensuring water supply and quality
Warragamba Dam, Sydney’s primary drinking water source, played a significant role in the delegation’s visit. While the dam itself is not used for flood management, reservoirs located further west serve that purpose while also supplying water for irrigation and towns. There have been ongoing debates about increasing the dam’s wall to enable it for flood mitigation. However, such an action would result in the flooding of upstream areas, including sites of cultural significance to Aboriginal communities.
Water quality monitoring emerged as a key concern for Warragamba Dam due to its role in providing drinking water. To ensure water quality, the dam utilises automatic water quality monitoring sensors that measure various parameters, including turbidity (water clarity). Adjustable slats in the dam wall control the entry of water from different depths, mitigating the impact of sediment or turbidity on the drinking water supply. In addition to automated monitoring, scientists regularly collect water quality samples for laboratory testing.
The delegation also highlighted the importance of community and stakeholder engagement in water management decisions. The management of Warragamba Dam showcased the significance of involving communities in the decision-making process, considering the trade-offs between securing water supply, flood mitigation, and ecological preservation.
Fires, flooding, and eel migration
The delegation learned about the impact of bushfires on the reservoir’s water quality. During severe fire events, surrounding areas experienced extensive burning, resulting in the degradation of water quality. To address this, firefighters prioritised protecting smaller water supply sources in the east, allowing them to provide water to Sydney until Warragamba’s water quality is improved. This highlighted the importance of incorporating resilience into infrastructure planning and system design.
An interesting discovery at Warragamba Dam was the migration of eels from the Coral Sea. Despite the lack of fish passageways, eels were found to ascend the side of the dam wall to continue their migration upstream. WaterNSW has installed monitoring cameras and utilised artificial intelligence technology to study the timing and frequency of eel migrations, emphasising the interconnectedness of people, infrastructure, and the environment.
Penrith Weir and fish passage
The delegation also visited Penrith Weir, where they met Dr Martin Mallen-Cooper, an expert in fish passage design. Dr Mallen-Cooper conducted extensive studies to optimise fish passages, including determining suitable gradients and accounting for turbulence to enable fish migration upstream. The fishway at Penrith Weir incorporates adjustable vertical slots to control velocity and turbulence, ensuring a successful passage for fish. The delegation noted the presence of ten similar fishways along the river, reflecting a commitment to maintaining ecological balance while harnessing water resources.
Exploring new horizons
The delegation visit by the Royal Irrigation Department of Thailand to Australia was an opportunity to share insights into flood management infrastructure and water management strategies. The focus on Warragamba Dam highlighted the delicate balance between water supply, flood mitigation, and environmental preservation. The delegation’s interactions with experts and stakeholders shed light on the importance of community engagement and ecological considerations in successful water management practices. By sharing knowledge and experiences, such delegation visits play a crucial role in fostering international collaboration and improving water management worldwide.
AWP currently provides technical support for an activity focussed on improving reservoir water quality management in Thailand which includes contributing to water quality monitoring manuals, support in building capacity through targeted training in Thailand and an exchange visit to Australia. Griffith University is delivering this work which began in April 2022.