Understanding regional streamflow trend magnitudes in the Southern Murray-Darling Basin, Australia

ABSTRACT

Understanding long-term trends in streamflow is important for water resource management. In this study, we investigate the long-term streamflow trends at 47 gauging sites within the southern Murray-Darling Basin (MDB), Australia. This study aims to estimate regional streamflow trends while understanding the impact of catchment characteristics on the spatial variation in these trends. To achieve this, we applied a Bayesian hierarchical model (BHM) to make the best use of available streamflow records from multiple sites and catchment characteristics such as climate, terrain, geology, land use and vegetation. The results show that streamflow trends from tested sites are consistently negative, with magnitudes of up to 2.7% per year relative to the annual average flow. We also find that spatial variability in trends can be best linked to differences in average climatic and terrain conditions. This finding can be used to inform future water planning for consumptive and environmental uses in the MDB.

KEYWORDS:

• Regional streamflow trend
• Bayesian hierarchical model
• catchment characteristics

Acknowledgments

The authors would like to thank Ji Li and Hongru Guo for providing preliminary analysis and data acquisition for this research. We thank Jie Jian for assisting in spatial data preprocessing. We thank Brad Neal for his valuable feedback.

Consent to participate

The authors consent to participate in this manuscript.

Consent to publish

The authors consent to publish this manuscript.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Authors contributions

Z Gao: Conceptualization, Methodology, Software, Data Curation, Writing – Original Draft; D Guo: Software, Investigation, Validation, Writing – Review & Editing; MC Peel: Writing – Review & Editing; Supervision, Funding acquisition; MJ Stewardson: Writing – Review & Editing, Supervision, Funding acquisition.

Availability of data and material

All streamflow data can be freely downloaded from http://www.bom.gov.au/water/hrs/. We also provided sources of other data in Section 2.1 and Table S2 in the SI.

Supplementary material

Supplemental data for this article can be accessed online at https://doi.org/10.1080/13241583.2022.2074942

Additional information

Notes on contributors

Zitian Gao

Zitian Gao is a PhD student in the Department of Infrastructure Engineering at the University of Melbourne. She has been studying in environmental engineering for more than 9 years. Her recent PhD research work on irrigation benchmarking aims to identify the best irrigation practices to improve water use efficiency and productivity in Australian farms and irrigation districts. Her PhD research is part of an ARC linkage project that cooperated with an Australian water company and the local water utility.

Danlu Guo

Danlu Guo is a Research Associate in the Department of Infrastructure Engineering at the University of Melbourne. Danlu has 8 years of research experience that extend to multiple areas centred on environmental and hydrological engineering. Her past work spans across climate change impact assessment, catchment hydrology and water quality modelling, as well as irrigation and soil water modelling. In 2017, Danlu received her PhD from the University of Adelaide in hydro-climatology, for which she developed a practical approach to implement scenario-neutral framework to assess the impacts of climate change impacts on water resources systems. Her recent work has focused on using data-driven models to understand the spatial and temporal variability of water quality, and improving the modelling and forecasting capacities of irrigation scheduling.

Murray C. Peel

Murray C. Peel is a Senior Lecturer and ARC Future Fellow in the Department of Infrastructure Engineering at the University of Melbourne. He obtained his PhD (Geography) in 1999 from the University of Melbourne as part of the CRC for Catchment Hydrology. His hydrologic research and consulting activities at the University of Melbourne have produced over 100 publications, including 73 articles in international peer-reviewed journals and 9 book chapters. His research interests include: catchment hydrology; hydroclimatology; understanding the drivers of inter-annual variability of annual precipitation and runoff around the world; understanding and modelling the hydrologic impacts of land use change; understanding and modelling the hydrologic impacts of climate change and the uncertainty around those projections; improving hydrologic modelling under changing conditions; and drawing hydroclimatology insights from palaeoclimatology information.

Michael J. Stewardson

Michael J. Stewardson research has focused on interactions between hydrology, geomorphology and ecology in rivers. This has included physical habitat modelling, flowecology science, and innovation in environmental water practice. Michael has participated in this evolution of environmental water management in Australia through many advisory roles at all levels of government. More recently, his research has focused on the physical, chemical and biological processes in streambed sediments and their close interactions in regulating stream ecosystem services. This includes his current membership of the MDBA’s Advisory Committee on Social Environmental and Environmental Science (ACSEES). He also leads the Water Environment and Agriculture Platform in the Faculty of Engineering & IT (FEIT), is Director of the Mallee Regional Innovation Centre and is the interim CEO for the ONE Basin CRC, currently at proposal stage.