Hydroecology of the Lower Burdekin River Alluvial Aquifer and Associated Groundwater Dependent Ecosystems Colton Perna, Ruth O'connor and Benjamin Cook*
Total Page:16
File Type:pdf, Size:1020Kb
Hydroecology of the lower Burdekin River alluvial aquifer and associated groundwater dependent ecosystems Colton Perna, Ruth O'Connor and Benjamin Cook* March 2012 * FRC Environmental, Unit 1/7-9 Grant St. Cleveland, Queensland, 4163. ph 61 7 32863850 Prepared by: Water Planning Ecology, Water Planning Sciences, Department of Environment and Resource Management © The State of Queensland (Department of Environment and Resource Management) 2012 Copyright inquiries should be addressed to <[email protected]> or the Department of Environment and Resource Management, 41 George Street, Brisbane QLD 4000 ISBN 978-1-7423-0952 Disclaimer This document has been prepared with all due diligence and care, based on the best available information at the time of publication. The department holds no responsibility for any errors or omissions within this document. Any decisions made by other parties based on this document are solely the responsibility of those parties. Information contained in this document is from a number of sources and, as such, does not necessarily represent government or departmental policy. If you need to access this document in a language other than English, please call the Translating and Interpreting Service (TIS National) on 131 450 and ask them to telephone Library Services on +61 7 3224 8412. This publication can be made available in an alternative format (e.g. large print or audiotape) on request for people with vision impairment; phone +61 7 3224 8412 or email <[email protected]>. Citation Perna C, O'Connor, R & Cook, B 2012. Hydroecology of the lower Burdekin River alluvial aquifer and associated groundwater dependent ecosystems. Brisbane: Department of Environment and Resource Management, Queensland Government. Acknowledgements This project was funded by the Australian Government through the National Water Commission’s Raising National Water Standards Program. We thank reviewers who contributed significantly to the report: Moya Tomlinson, Niall Connolly, Tim Perry, Jonathan Marshall and Glenn McGregor. We also thank the expert panel members who provided input to the conceptual models and recommendations. We thank Pete Mettam for his assistance in the data collection, Alisha Steward for macroinvertebrate identification, Ray McGowin and the hydrology team at Ayr. Finally, thanks to Jan Tilden, Maria Vandergragt and Sara Clifford from DERM who produced and edited the conceptual models. External publications disclaimer The views and opinions expressed in this publication are those of the authors and do not necessarily reflect those of the Australian Government, the Minister for Sustainability, Environment, Water, Population and Communities or the National Water Commission. While reasonable efforts have been made to ensure that the contents of this publication are factually correct, the Commonwealth does 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. March 2012 #30083 Preface Through the Raising National Water Standards Program, the National Water Commission (NWC) provided funding to the former Queensland Department of Environment and Resource Management (DERM) to develop a groundwater modelling toolkit for the aquifers of the Lower Burdekin floodplain. The project is titled “Development of a Lower Burdekin Numerical Groundwater Flow and Solute Transport Model”. The project was managed by the Queensland Hydrology Unit of the Environment and Resource Sciences section of the Department. Prior to completion of the project, the Queensland Hydrology Unit became part of the newly formed Department of Science, Information Technology, Innovation and the Arts (DSITIA). Where relevant, all previous references to DERM have been changed to DSITIA. This report is part of a series of eleven technical reports produced for the project. The overarching title of all departmentally-produced reports is “Development of a hydrological modelling toolkit to support sustainable development of the Lower Burdekin groundwater system.” The full list of reports produced for this project are: 1. Review of modelling methods 2. Conceptualisation of the Lower Burdekin aquifer 3. Groundwater flow modelling of the Lower Burdekin aquifer 4. Instructional solute transport model of the Lower Burdekin aquifer 5. A re-evaluation of groundwater discharge from the Burdekin floodplain aquifers using geochemical tracers 6. Quantification of evapotranspiration in a groundwater dependent ecosystem 7. Geochemical assessment and reactive transport modelling of nitrogen dynamics in the Lower Burdekin coastal plain aquifer 8. Predictive uncertainty of the Lower Burdekin groundwater flow model 9. MODFLOW local grid refinement for the Lower Burdekin aquifer 10. Hydroecology of the Lower Burdekin River alluvial aquifer and associated groundwater dependent ecosystems 11. Pesticides in groundwater in the Lower Burdekin floodplain All reports were produced by DSITIA, with the exception of: – Report #5 which was authored by the National Centre for Groundwater Research and Training, Flinders University, Adelaide; and – Reports #10 and #11 which were completed in March 2012 as DERM reports. Contents Preface 3 Contents iv List of tables vi List of figures vi Executive summary ix 1 Introduction 1 1.1 Project scope and objectives 1 1.2 National and Queensland groundwater policy 1 1.3 Overview of groundwater hydroecology 2 1.3.1 Definition of groundwater 2 1.3.2 Definition of hydroecology 3 1.3.3 Groundwater dependent ecosystems 3 2 Overview of the lower Burdekin groundwater system 6 2.1 Geographical setting 6 2.2 Ecological values associated with groundwater 7 2.2.1 Significant wetlands 7 2.2.2 Ecosystems used to assess impacts arising from changes to groundwater hydrology 8 2.3 Pressures on the lower Burdekin groundwater system 9 2.3.1 Water resource development 11 2.4 Conceptual models of hydroecological processes 13 2.4.1 Conceptual models of groundwater hydroecology pre-development 13 2.4.2 Conceptual models of current groundwater hydroecology 20 3 Characterisation of hydrological alteration to the lower Burdekin groundwater system 24 3.1 Indicators of hydrological alteration of the water table 24 3.2 Indicators of hydrological alteration to Barratta Creek 30 3.2.1 Median and maximum discharge 31 3.2.2 Cease to flow 32 4 Ecological assessments of the lower Burdekin groundwater system 34 4.1 Wetland assessments 34 4.1.1 Assemblage structure of diatoms 34 4.1.2 Assemblage structure of macroinvertebrates 36 4.2 Ecology of the aquifer environment 43 4.2.1 Stygofauna diversity 43 iv 4.2.2 Groundwater microbial ecology 45 5 Synthesis of findings: key hydrology - ecology relationships 48 5.1 Representation of flow and groundwater dependent ecosystem components and processes using ecological assets 48 5.2 Ecological assets on the Burdekin floodplain 48 5.2.1 Wetland plants – drying guild (shallow non-permanent palustrine and shallow non- permanent estuarine wetlands) 49 5.2.2 Wetland plants – wetland guild (permanent riverine wetlands) 49 5.2.3 Permanent riverine wetlands and fish community structure 50 5.2.4 Specific wetlands with high conservation values 51 5.2.5 Subterranean ecosystems 51 5.2.6 Phreatophytic vegetation 52 6 Knowledge gaps 53 6.1 Knowledge gaps and recommendations for future research 53 6.2 Recommendations for groundwater management 55 7 References 57 Appendix A Details of expert panel workshop to review conceptual models and management recommendations 64 Appendix B Legend for conceptual models 75 Appendix C Complete results for indicators of hydrological alteration 76 Appendix D The environmental history of Burdekin River wetlands as inferred from sediment and fossil diatom records (consultant's report) 77 Appendix E Methods for stygofauna genetic analyses 99 Appendix F Bacteria of the alluvial aquifer, lower Burdekin floodplain (consultant's report) 101 v List of tables Table 1 Ecologically-relevant thresholds for depth to water table (DTWT) for the lower Burdekin system. 24 Table 2 Putative ecologically-relevant metrics for setting hydrological foundations of groundwater systems. 26 Table 3 Time line of months with zero flow (black shading) and months with greater than zero flow (grey shading) in years 1975 to 2011. ND = no data. 33 Table 4 Details of wetland sites sampled for macroinvertebrates. 38 Table 5 List of bathynellaceans and lineages found in the lower Burdekin River alluvial aquifer. 44 List of figures Figure 1 Schematic representation of the major hydrological features of an alluvial groundwater system. Source: G. McGregor. 2 Figure 2. Simplified schematic diagram of subterranean groundwater-dependent ecosystems and hydrological compartments that can interact with them (modified from Boulton et al. 2008) 4 Figure 3 Map of the lower Burdekin floodplain showing major irrigation infrastructure. 6 Figure 4 Panorama diagram of the lower Burdekin floodplain showing four key wetland types. 10 Figure 5 Conceptual model of water resource development in the lower Burdekin floodplain. See Appendix B for legend. 12 Figure 6 Conceptual model of pre-development wet and dry season conditions in shallow non-permanent palustrine wetlands. See Appendix B for legend. 14 Figure 7 Conceptual model for pre-development wet and dry season conditions in non- permanent riverine wetlands. See Appendix B for legend. 16 Figure 8 Conceptual model of pre-development wet