Assessing water security under long-term climate to support water management: A case study from Bega-Brogo River NSW

Tóm tắt

In New South Wales (NSW), water resources are governed by water sharing plans (WSPs). WSPs are legally binding instruments under the Water Management Act 2000 that regulate how water is allocated between environmental needs and consumptive uses. As the cornerstone of NSW’s broader water management framework, WSPs establish rules for sharing water across social, economic, agricultural, cultural, and environmental domains.
Many waterways in NSW Coastal region have been classified as being under high or medium hydrological and environmental stress. While there is enough water in the region to meet agricultural demands on an annual basis, most extraction takes place in the drier summer period when temperatures are high and flows are low. This puts high stress on the flora and fauna that rely on the rivers. Longer droughts and reduced flows due to climate variability and change will amplify these impacts.
The NSW Government has invested in new climate datasets and improved modelling that provide a more sophisticated understanding of historic climate variability in the South Coast region, as well as likely future climate risks moving from making decisions that are based largely on single worst-case scenarios to a much more comprehensive understanding of natural variability and potential extreme events based on modelling using daily stochastic data of 13,000 years.
This paper presents a case study of the Bega-Brogo River System, detailing how water is allocated under the relevant WSPs. The paper further examines water security analysis under long-term climate variability. The impact of climate change and East Coast Lows on water availability and allocation within the catchment is also assessed to better understand the climate risks faced by water users and the environment.