Department of Environment and Resource Management Improved Assessment of the Impact of Stock and Domestic Farm Dams in Queensland STATEWIDE ASSESSMENT: REPORT 1 Methods and Inputs Final 28 March 2012 Department of Environment and Resource Management Improved Assessment of the Impact of Stock and Domestic Farm Dams in Queensland STATEWIDE ASSESSMENT: REPORT 1 Methods and Inputs Final 28 March 2012 This project was funded by the Australian Government through the National Water Commission’s Raising National Water Standards Program. Sinclair Knight Merz ABN 37 001 024 095 Cnr of Cordelia and Russell Street South Brisbane QLD 4101 Australia PO Box 3848 South Brisbane QLD 4101 Australia Tel: +61 7 3026 7100 Fax: +61 7 3026 7300 Web: www.globalskm.com COPYRIGHT: This work is copyright. Apart from any use permitted under the Australian Copyright Act 1968, no part of this report may be reproduced by any process, nor may any other exclusive right be exercised, without the permission of the Department of Environment and Resource Management, 2012. LIMITATION: This report has been prepared on behalf of and for the exclusive use of Sinclair Knight Merz Pty Ltd’s Client, and is subject to and issued in connection with the provisions of the agreement between Sinclair Knight Merz and its Client. Sinclair Knight Merz accepts no liability or responsibility whatsoever for or in respect of any use of or reliance upon this report by any third party. The SKM logo trade mark is a registered trade mark of Sinclair Knight Merz Pty Ltd. Improved assessment of the Impact of Stock and Domestic Farm Dams in Queensland Statewide Assessment: Report 1 – Methods and Inputs Contents Executive Summary vi 1. Introduction 1 1.1. Scope of this report 1 1.2. Format of the report 1 2. Overview of farm dams 3 3. Modelling the impact of stock and domestic farm dams 6 3.1. STEDI model inputs 7 4. Inputs and methods 9 4.1. Streamflow and climate 11 4.1.1. Streamflow 11 4.1.2. Evapotranspiration and rainfall 11 4.1.3. Collation of streamflow, evapotranspiration and rainfall files 12 4.2. Collation of farm dam GIS layers 12 4.3. Identification of stock and domestic dams 16 4.3.1. Adopted approach – Exclusion due to landuse type 16 4.3.2. Alternative approach 18 4.4. Determining the number of farm dams 19 4.5. Determining the volume of stock and domestic farm dams 22 4.5.1. Adopted Approach - Assignment of surface area for point dams 24 4.5.2. Adopted approach – Surface area to volume equation 25 4.5.3. Alternative approach 31 4.6. Regional volume estimate 31 4.6.1. Adopted approach 31 4.6.2. Alternative approach 36 4.7. Determining the size distribution of stock and domestic farm dams 36 4.7.1. Adopted approach - Size distribution of dams 36 4.7.2. Alternative approach 39 4.8. Adopted number and volume of stock and domestic dams 40 4.9. Determining the local catchment area of stock and domestic farm dams 43 4.9.1. Adopted approach – Regression equation 43 4.9.2. Alternative approach 50 4.10. Determining the usage from stock and domestic farm dams 50 4.10.1. Adopted approach – Demand factor 50 4.10.2. Alternative approach 56 5. Assessment of alternative methods 58 SINCLAIR KNIGHT MERZ F:\Projects\QE09896_Qld Farm Dams\Reports\3_Statewide Assessment\2_Final\QE09896_Final_Statewide Assessment_Report1_120328.docxPAGE i Improved assessment of the impact of stock and domestic farm dams in Queensland Statewide Assessment: Report 1 – Methods and Inputs 5.1. Interaction of STEDI input estimation methods 58 5.2. Identification of stock and domestic dams 59 5.3. Determining the volume of stock and domestic farm dams 62 5.4. Determining the size distribution of stock and domestic farm dams 63 5.5. Determining the local catchment area of stock and domestic farm dams 64 5.6. Determining the usage from stock and domestic farm dams 67 5.7. Regional volume estimate 68 5.8. Summary of proposed alternatives 71 6. Conclusions and further work 73 7. Limitations of this study 75 References 76 Appendix A Datasets available and/or utilised 78 A.1 Geoscience Australia Waterbodies 78 A.2 Referable farm dams dataset from DERM 78 A.3 Extended farm dams dataset from DERM 79 A.4 Dams digitised for this project 79 A.5 Climate data from SILO 79 A.6 Climate data from Bureau of Meteorology 79 A.7 LIDAR Data from DERM 80 A.8 Digital elevation model from DERM 80 A.9 Digital elevation model from Geoscience Australia 80 A.10 Digital elevation model from Geoscience Australia 80 A.11 Aerial photography from DERM 81 A.12 Bureau of Rural Statistics 2005-06 Landuse dataset 81 Appendix B Glossary and acronyms 82 Appendix C Landuse based stock and domestic assessment 85 Appendix D Estimated farm dam volume from regionalisation 87 Appendix E Demand factor assessment 89 Table of Figures Figure 1 Simplified water balance for a farm dam (Sinclair Knight Merz, 2011c) 6 Figure 2 Procedure for estimating the number and volume of stock and domestic dam for STEDI 8 Figure 3 Interaction of input estimation methods (when a spatial layer is available) 10 SINCLAIR KNIGHT MERZ F:\Projects\QE09896_Qld Farm Dams\Reports\3_Statewide Assessment\2_Final\QE09896_Final_Statewide Assessment_Report1_120328.docxPAGE ii Improved assessment of the impact of stock and domestic farm dams in Queensland Statewide Assessment: Report 1 – Methods and Inputs Figure 4 Interaction of input estimation methods (when a spatial layer is not available) 10 Figure 5 Extent of data used to estimate the number of farm dams 15 Figure 6 Process diagram to determine if a dam is stock and domestic or not 18 Figure 7 Number of dams estimated in each modelling area 21 Figure 8 Example of the point and polygon dams captured by Geoscience Australia. Note that a surface area has been applied to the points as described in Section 4.5.1. 23 Figure 9 Example of the LiDAR capture of a dam in the Condamine River catchment. Note that the full supply level of the dam is indicated by the blue line, while the surface area of the water held within the dam (residual volume) is indicated by the red line. 26 Figure 10 Relationship between farm dam Surface Area and Volume 27 Figure 11 Relationship between farm dam Surface Area and Volume – with confidence limits 28 Figure 12 Relationship between farm dam Surface Area and Volume – comparison of regional equations 29 Figure 13 Extent of data used to improve the relationship between surface area and farm dam volumes in Queensland 30 Figure 14 Observed stock and domestic farm dam volume compared to the volume estimated by Equation 2 34 Figure 15 Observed stock and domestic farm dam volume compared to the volume estimated by Equation 2 on a log scale 34 Figure 16 Observed stock and domestic farm dam density compared to the density estimated by Equation 2 35 Figure 17 Observed stock and domestic farm dam density compared to the density estimated by Equation 2 on a log scale 35 Figure 18 Distribution of stock and domestic dams by volume (and size class) 37 Figure 19 Distribution of stock and domestic dams by numbers (and size class) 38 Figure 20 Final Queensland stock and domestic dams distribution 39 Figure 21 Example of the relationship between catchment area and local catchment area (SKM, 2011b) 43 Figure 22 Comparison of observed and calculated proportion local catchment area 47 Figure 23 Comparison of observed and calculated local catchment area (km2) 47 Figure 24 Comparison of observed and calculated local catchment area (CA > 50 km2) 48 Figure 25 Extent of data used to improve the understanding of the local catchment area in Queensland 49 Figure 26 Distribution of farm dam demand factors 56 Figure 27 Interaction of STEDI input estimation methods (during development of the methods) 59 SINCLAIR KNIGHT MERZ F:\Projects\QE09896_Qld Farm Dams\Reports\3_Statewide Assessment\2_Final\QE09896_Final_Statewide Assessment_Report1_120328.docxPAGE iii Improved assessment of the impact of stock and domestic farm dams in Queensland Statewide Assessment: Report 1 – Methods and Inputs Table of Equations Equation 1 Relationship between farm dam surface area and volume 27 Equation 2 Regionalisation equation for volume of farm dams 33 Equation 3 Existing relationship to calculate the local catchment area regulated by farm dams 44 Equation 4 Queensland relationship to calculate the local catchment area regulated by farm dams 45 Equation 5 Demand factor as a function of annual average demand and dam volume 51 SINCLAIR KNIGHT MERZ F:\Projects\QE09896_Qld Farm Dams\Reports\3_Statewide Assessment\2_Final\QE09896_Final_Statewide Assessment_Report1_120328.docxPAGE iv Improved assessment of the impact of stock and domestic farm dams in Queensland Statewide Assessment: Report 1 – Methods and Inputs Document history and status Revision Date issued Reviewed by Approved by Date approved Revision type Draft P. Jordan P. Jordan 24/02/2012 Internal review Draft R. Morden R. Morden 27/02/2012 Internal review Draft 9/03/2012 DERM Steering Client review Committee Final 28/03/2012 P. Jordan P. Jordan 28/03/2012 Internal review Distribution of copies Revision Date issued Copy no Quantity Issued to Draft 29/02/2012 1 1 P. Onta Final 28/03/2012 1 1 P. Onta Printed: 28 March 2012 Last saved: 28 March 2012 03:50 PM F:\Projects\QE09896_Qld Farm Dams\Reports\3_Statewide File name: Assessment\2_Final\QE09896_Final_Statewide Assessment_Report1_120328.docx Author: Nicola Logan and Chloe Wiesenfeld Project manager: Nicola Logan Name of organisation: DERM Name of project: Improved assessment of stock and domestic farm dams in Queensland Name of document: Statewide Assessment: Report 1 – Methods and Inputs Document version: Final Project number: QE09896 SINCLAIR KNIGHT MERZ F:\Projects\QE09896_Qld Farm Dams\Reports\3_Statewide Assessment\2_Final\QE09896_Final_Statewide Assessment_Report1_120328.docxPAGE v Improved assessment of the Impact of Stock and Domestic Farm Dams in Queensland Statewide Assessment: Report 1 – Methods and Inputs Executive Summary Queensland is home to a number of high value agricultural activities and for many of these activities water is supplied either through large irrigation schemes, floodplain storages and water harvesting, or by direct pumping from waterways.