Characterisation of Flow in Regulated and Unregulated Streams in Eastern Australia Characterisation of Flow in Regulated and Unregulated Streams in Eastern Australia Jane Growns Murray–Darling Freshwater Research Centre Nick Marsh Centre for Environmental Applied Hydrology Cooperative Research Centre for Freshwater Ecology Technical Report 3/2000 September 2000 Centre for Environmental Applied Hydrology Cooperative Research Centre for Freshwater Ecology i Characterisation of Flow in Regulated and Unregulated Streams in Eastern Australia The Cooperative Research Centre for Freshwater Ecology improves the health of Australia’s rivers, lakes and wetlands through research, education and knowledge exchange. It was established in 1993 under the Australian Government’s Cooperative Research Centre Program. The Cooperative Research Centre for Freshwater Ecology is a collaborative venture between: • ACTEW Corporation • CSIRO Land and Water • Department of Land and Water Conservation, NSW • Department of Natural Resources, Queensland • Department of Natural Resources and Environment, Victoria • Environment ACT • Environment Protection Authority, NSW • Environment Protection Authority, Victoria • Goulburn–Murray Rural Water Authority • Griffith University • La Trobe University • Lower Murray Water • Melbourne Water • Monash University • Murray-Darling Basin Commission • Murray-Darling Freshwater Research Centre • Sunraysia Rural Water Authority • Sydney Catchment Authority • University of Canberra Cooperative Research Centre for Freshwater Ecology Ph: 02 6201 5168 Fax: 02 6201 5038 Email: [email protected] http://freshwater.canberra.edu.au Printed in September 2000 Growns, Jane. Characterisation of flow in regulated and unregulated streams in eastern Australia. Bibliography. ISBN 1 876810 06 8 Streamflow – Australia, Eastern. I. Cooperative Research Centre for Freshwater Ecology (Australia). II. Title. (Series : Technical report (Cooperative Research Centre for Freshwater Ecology) ; 2000/3). 551.483/0994 Editing and layout: Science Text Processors Canberra, [email protected] Printing and binding: Elect Printing, Fyshwick, ACT ii Cooperative Research Centre for Freshwater Ecology Characterisation of Flow in Regulated and Unregulated Streams in Eastern Australia CONTENTS EXECUTIVE SUMMARY.......................................................................................................................1 Acknowledgements ................................................................................................................................3 1. Introduction ......................................................................................................................................5 1.1. Background ..........................................................................................................................5 1.2. Purpose ................................................................................................................................5 1.3. Approach ..............................................................................................................................6 2. Methods ..........................................................................................................................................7 2.1. Selection of stream gauges, and quality control...................................................................7 2.1.1 Continuous 20-year period ......................................................................................7 2.1.2 Rating table continuity .............................................................................................7 2.1.3 Missing data, and details recorded..........................................................................7 2.1.4 Incomplete variable record ......................................................................................8 2.2. Selection of hydrological variables .......................................................................................8 2.2.1 Summary of hydrological variables..........................................................................9 2.2.2 Long-term variables.................................................................................................9 2.2.3 Variables for high-flow spell analysis.....................................................................10 2.2.4 Variables for low-flow spell analysis ......................................................................12 2.2.5 Moving-average variables .....................................................................................12 2.2.6 Cessation-of-flow variables....................................................................................13 2.2.7 Variables concerned with the rise and fall of the hydrograph................................13 2.2.8 Monthly flow variables ...........................................................................................14 2.3. Calculation of hydrologic variables.....................................................................................15 2.4. Statistical analysis ..............................................................................................................15 2.4.1 Cross correlation....................................................................................................16 2.4.2 Multivariate analyses .............................................................................................17 3. Results and interpretation.............................................................................................................19 3.1. Gauges selection................................................................................................................19 3.1.1 Measures of central tendency ...............................................................................19 3.1.2 Variables used in multivariate analysis..................................................................19 3.2. Multivariate analysis ...........................................................................................................19 3.2.1 All 107 stations.......................................................................................................19 3.2.2 Permanent stations................................................................................................21 3.2.3 Simulated data.......................................................................................................24 4. Discussion ......................................................................................................................................25 5. References .....................................................................................................................................27 Appendix 1: Summary of suitable stream gauges .........................................................................29 Appendix 2: Explanatory notes on the calculation of hydrological variables............................35 A2.1 Elements of the VBA code....................................................................................35 A2.2 Getting the raw data.............................................................................................35 A2.3 Setting up the reporting sheet...............................................................................35 A2.4 Daily flow summary..............................................................................................36 A2.5 High-flow spell analysis........................................................................................38 A2.6 Low-flow spell analysis.........................................................................................39 A2.7 Moving average ...................................................................................................40 A2.8 Cessation of flow..................................................................................................40 A2.9 Rise and fall of the hydrograph.............................................................................40 A2.10 Monthly flow analysis ...........................................................................................41 Cooperative Research Centre for Freshwater Ecology iii Characterisation of Flow in Regulated and Unregulated Streams in Eastern Australia Appendix 3: Sample output file of hydrological variables............................................................42 Appendix 4: List of hydrological variables used in this study that are identical to those used in other studies ...............................................................52 Appendix 5: Correlations from PCC................................................................................................53 Appendix 6: Group statistics from GSTA.......................................................................................57 List of tables and figures Table 1 Long-term variables........................................................................................................10 Table 2 High-flow variables .........................................................................................................11 Table 3 Low-flow variables ..........................................................................................................12 Table 4 Moving-average variables ..............................................................................................13 Table 5 Cessation-of-flow variables.............................................................................................13