Background review Co-produced water - risks to aquatic ecosystems This background review was commissioned by the Department of the Environment on the advice of the Interim Independent Expert Scientific Committee on Coal Seam Gas and Coal Mining. The review was prepared by Sinclair Knight Merz Pty Ltd and revised by the Department of the Environment following peer review. June 2014 Copyright © Copyright Commonwealth of Australia, 2014. Co-produced water - risks to aquatic ecosystems, Background review is licensed by the Commonwealth of Australia for use under a Creative Commons By Attribution 3.0 Australia licence with the exception of the Coat of Arms of the Commonwealth of Australia, the logo of the agency responsible for publishing the report, content supplied by third parties, and any images depicting people. For licence conditions see: http://creativecommons.org/licenses/by/3.0/au/ This report should be attributed as ‘Co-produced water - risks to aquatic ecosystems, Background review, Commonwealth of Australia 2014’. The Commonwealth of Australia has made all reasonable efforts to identify content supplied by third parties using the following format ‘© Copyright, [name of third party] ’. Enquiries concerning reproduction and rights should be addressed to: Department of the Environment, Public Affairs GPO Box 787 Canberra ACT 2601 Or by email to: [email protected] This publication can be accessed at: www.iesc.environment.gov.au Acknowledgements This background review was commissioned by the Department of the Environment on the advice of the Interim Independent Expert Scientific Committee on Coal Seam Gas and Coal Mining. The review was prepared by Sinclair Knight Merz Pty Ltd with input from Professor Barry Hart, Associate Professor Heather Chapman and Professor Ian Cartwright. It was revised by the Department of the Environment following peer review by Grantley Smith and Dr Will Glamore (University of New South Wales), Dr Graeme Batley (CSIRO) and James Lazorchak, Joe Beauman and Stephen Kraemer (US Environmental Protection Agency), and relevant Queensland, New South Wales and South Australian Government departments. Disclaimer The views and opinions expressed in this publication are those of the authors and do not necessarily reflect those of the Australian Government or the Minister for the Environment or the Interim Independent Expert Scientific Committee on Coal Seam Gas and Coal Mining or the statutory Independent Expert Scientific Committee on Coal Seam Gas and Large Coal Mining Development (IESC). While reasonable efforts have been made to ensure that the contents of this publication are factually correct, the Commonwealth and IESC do not accept responsibility for the accuracy or completeness of the contents, and shall not be liable for any loss or damage that may be occasioned directly or indirectly through the use of, or reliance on, the contents of this publication. Addendum Changes to state government departments have occurred since the finalisation of this report by the authors. The Queensland, New South Wales and South Australian Government agencies were contacted and updated information provided in September 2013; however, no guarantees can be Background review: co-produced water - risks to aquatic ecosystems made as to the completeness of these updates. Up-to-date information should be sourced from the relevant department. On 1 January 2013, the Queensland Water Commission (QWC) ceased operations. The Office of Groundwater Impact Assessment (OGIA) retains the same powers as the former QWC under Chapter 3 of the Water Act 2000 (Qld). Sinclair Knight Merz Pty Ltd is now Jacobs SKM. page 3 of 98 Background review: co-produced water - risks to aquatic ecosystems Contents Copyright ..............................................................................................................................2 Acknowledgements ..............................................................................................................2 Disclaimer .............................................................................................................................2 Addendum ............................................................................................................................2 Summary ..................................................................................................................................6 Abbreviations ..........................................................................................................................10 Glossary ................................................................................................................................. 13 1 Introduction ........................................................................................................................16 2 Co-produced water ............................................................................................................17 2.1 Co-produced water from coal seam gas .................................................................... 17 2.2 Co-produced water from coal mining operations ....................................................... 19 2.3 Aquatic ecosystems ................................................................................................... 20 3 Water quality impacts on receiving environments ............................................................. 23 3.1 Importance of water quality for aquatic ecosystems and associated environmental values ................................................................................................................................. 23 3.2 Water quality threats from co-produced water ........................................................... 23 3.3 Water treatment ......................................................................................................... 31 3.4 Monitoring requirements ............................................................................................ 37 3.5 Knowledge gaps and recommendations .................................................................... 37 3.6 Summary of critical water quality issues .................................................................... 39 4 Water quantity change impacts on aquatic ecosystems .................................................... 41 4.1 Importance of flow regimes for aquatic ecosystems and associated environmental values ................................................................................................................................. 41 4.2 What hydrological changes are expected as a result of discharge of co-produced water? ................................................................................................................................. 42 4.3 What types of stream are likely to be affected by discharge of co-produced water? . 46 4.4 Quantifying risks to individual waterways .................................................................. 47 4.5 Reducing risks associated with discharging co-produced water................................ 49 4.6 Examples of co-produced water being released into waterways with high seasonal variability ............................................................................................................................49 4.7 Knowledge gaps ........................................................................................................ 51 4.8 Summary of critical water quantity issues .................................................................. 52 5 Risk management frameworks for the assessment of environmental impacts .................. 54 5.1 Ecological risk assessment ........................................................................................ 54 5.2 Cumulative risk assessment frameworks .................................................................. 68 5.3 Risk assessment frameworks for other endpoints ..................................................... 69 page 4 of 98 Background review: co-produced water - risks to aquatic ecosystems 5.4 Suitability of the ERA process for co-produced water................................................ 69 6 Industry practice ................................................................................................................71 6.1 Environmental impact assessments .......................................................................... 71 6.2 Overseas studies ....................................................................................................... 79 6.3 Recent changes to legislation in Australia ................................................................. 82 6.4 Mitigation and management options .......................................................................... 82 7 Synthesis ...........................................................................................................................84 7.1 Water quality ..............................................................................................................84 7.2 Water quantity ............................................................................................................85 7.3 Risk assessment and water management ................................................................. 86 7.4 Critical knowledge gaps ............................................................................................. 87 8 References ........................................................................................................................88