Adaptive Management of Environmental Flows: Using Irrigation Infrastructure to Deliver Environmental Benefits During a Large Hypoxic Blackwater Event in the Southern Murray–Darling Basin, Australia
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Widespread flooding in south-eastern Australia in 2010 resulted in a hypoxic (low dissolved oxygen, DO) blackwater (high dissolved carbon) event affecting 1800 kilometres of the Murray–Darling Basin. There was concern that prolonged low DO would result in death of aquatic biota. Australian federal and state governments and local stakeholders collaborated to create refuge areas by releasing water with higher DO from irrigation canals via regulating structures (known as ‘irrigation canal escapes’) into rivers in the Edward–Wakool system. To determine if these environmental flows resulted in good environmental outcomes in rivers affected by hypoxic blackwater, we evaluated (1) water chemistry data collected before, during and after the intervention, from river reaches upstream and downstream of the three irrigation canal escapes used to deliver the environmental flows, (2) fish assemblage surveys undertaken before and after the blackwater event, and (3) reports of fish kills from fisheries officers and local citizens. The environmental flows had positive outcomes; mean DO increased by 1–2 mg L−1 for at least 40 km downstream of two escapes, and there were fewer days when DO was below the sub-lethal threshold of 4 mg L−1 and the lethal threshold of 2 mg L−1 at which fish are known to become stressed or die, respectively. There were no fish deaths in reaches receiving environmental flows, whereas fish deaths were reported elsewhere throughout the system. This study demonstrates that adaptive management of environmental flows can occur through collaboration and the timely provision of monitoring results and local knowledge.
KeywordsEnvironmental flows Blackwater Dissolved oxygen Fish kills Refugia Adaptive management
The authors thank Edward–Wakool landholders, the Wakool River Association and the Edward–Wakool Anglers Association for their interest in the project and providing access to monitoring sites on their properties. Thank you to James Dyer and Elena Griffiths for field assistance. Figure one was prepared by Deanna Duffy (Charles Sturt University Spatial Analysis Unit). Fish collections were carried out under New South Wales Animal Care and Ethics Authority 10/01 and Scientific Collection Permit P01/0059(A). Funding for the water quality monitoring was provided by Charles Sturt University and also funding to the (then) Murray Catchment Management Authority (MCMA) by the Australian Government under the Caring for our Country Programme. Funding for the fish surveys was provided by the MCMA, New South Wales Department of Primary Industries (Fisheries) and the (then) Department of the Environment, Heritage, Water and the Arts. Thanks to the editor and several reviewers for their constructive comments on drafts of this manuscript.
Compliance with Ethical Standards
Conflict of Interest
The authors declare that they have no competing interests.
- Carpenter SR, Biggs R (2009) Freshwaters: managing across scales in space and time. In: Chapin FS, Folke C, Kofinas GP (eds) Principles of ecosystem stewardship – resilience-based natural resource management in a changing world. Springer Science+Business Media, New York, 197–220CrossRefGoogle Scholar
- Commonwealth Environmental Water Office (2013) Framework for determining Commonwealth environmental water use. Commonwealth Environmental Water Office, CanberraGoogle Scholar
- Le Quesne T, Kendy E, Weston D (2010) The implementation challenge: taking stock of government policies to protect and restore environmental flows, The Nature Conservancy and WWF. http://d2ouvy59p0dg6k.cloudfront.net/downloads/the_implementation_challenge.pdf. Accessed 16 Jan 2017
- Meredith S, Beesley L (eds) (2009) Watering floodplain wetlands in the Murray–Darling Basin to benefit fish: a discussion with managers. Arthur Rylah Institute for Environmental Research Technical Report Series No. 189, Department of Sustainability and Environment, Heidelberg, VictoriaGoogle Scholar
- Murray Darling Basin Authority (2011) Murray–Darling Basin Authority annual report 2010–11. MDBA publication No. 218/11, MDBA, CanberraGoogle Scholar
- Richter BD, Thomas GA (2007) Restoring environmental flows by modifying dam operations. Ecol Soc 12(1): 12. [online] URL: http://www.ecologyandsociety.org/vol12/iss1/art12/
- Rowland S (2004) Overview of the history, fishery, biology and aquaculture of Murray cod (Maccullochella peelii peelii). Workshop on management of Murray cod in the Murray–Darling Basin, Canberra, pp 38–61Google Scholar
- Small K, Kopf RK, Watts RJ, Howitt J (2014) Hypoxia, blackwater and fish kills: experimental lethal oxygen thresholds in juvenile predatory lowland river fishes. PLoS ONE 9(4):e94524. https://doi.org/https://doi.org/10.1371/journal.pone.0094524 CrossRefGoogle Scholar
- Thiem JD, Wooden IJ, Baumgartner LJ, Butler GL, Forbes JP, Conallin J (2016). Recovery from a fish kill in a semi-arid Australian river: can stocking augment natural recruitment processes. Austral Ecol https://doi.org/10.1111/aec.12424
- van Dijk AIJM, Beck HE, Crosbie RS, de Jeu RAM, Liu YY, Podger GM, Timbal B, Viney NR (2013) The millennium drought in Southeast Australia (2001–2009): natural and human causes and implications for water resources, ecosystems, economy, and society. Water Resour Res 49: https://doi.org/10.1002/wrcr.20123
- Watts RJ, McCasker N, Thiem J, Howitt JA, Grace M, Healy S, Kopf RK, Dyer JG, Conallin A, Wooden I, Baumgartner L, Bowen P (2014) Monitoring the ecosystem responses to Commonwealth environmental water delivered to the Edward-Wakool river system, 2013-14. Institute for Land, Water and Society, Charles Sturt University, Final Report. Prepared for Commonwealth Environmental Water. http://www.environment.gov.au/water/cewo/publications/monitoring-ecosystem-responses-cew-edward-wakool-river-system-2013-14-final-report
- Watts RJ, McCasker N, Thiem J, Howitt JA, Grace M, Kopf RK, Healy S, Bond N (2015) Commonwealth Environmental Water Office Long Term Intervention Monitoring Project: Edward-Wakool Selected Area Technical Report, 2014–15. Commonwealth Environmental Water, CanberraGoogle Scholar