Review of Moree and Environs Flood Study/Floodplain Risk Management Study and Plan Flood Study Calibration Report Moree Plains Shire Council 1091-01-D3, 21 March 2016 Report Title Review of Moree and Environs Flood Study/Floodplain Risk Management Study and Plan: Flood Study Calibration Report Client Moree Plains Shire Council PO Box 420, Moree, NSW, 2400 Report Number 1091-01-D3 Revision Number Report Date Report Author Reviewer 0 27 October 2015 GR SM 1 23 December 2015 HG GR 2 29 January 2016 HG GR 3 21 March 2016 HG GR For and on behalf of WRM Water & Environment Pty Ltd Level 9, 135 Wickham Tce, Spring Hill PO Box 10703 Brisbane Adelaide St Qld 4000 Tel 07 3225 0200 Greg Roads Principal Engineer NOTE: This report has been prepared on the assumption that all information, data and reports provided to us by our client, on behalf of our client, or by third parties (e.g. government agencies) is complete and accurate and on the basis that such other assumptions we have identified (whether or not those assumptions have been identified in this advice) are correct. You must inform us if any of the assumptions are not complete or accurate. We retain ownership of all copyright in this report. Except where you obtain our prior written consent, this report may only be used by our client for the purpose for which it has been provided by us. wrmwater.com.au 1091-01-D3| 21 March 2016 | Page 2 Contents 1 Introduction _______________________________________________________ 13 1.1 Overview _____________________________________________________________ 13 1.2 Legislative framework __________________________________________________ 13 1.3 Adopted approach _____________________________________________________ 15 1.4 Report structure ______________________________________________________ 15 2 Background _______________________________________________________ 16 2.1 Previous studies _______________________________________________________ 16 2.1.1 Cameron McNamara Consultants, 1983 ______________________________ 16 2.1.2 Paterson Consultants, 1993 _______________________________________ 16 2.1.3 Paterson Consultants, 2003 _______________________________________ 17 2.1.4 DPI Water, 2014 _________________________________________________ 17 2.2 Study scope __________________________________________________________ 18 3 Drainage characteristics _____________________________________________ 19 3.1 Catchment overview ___________________________________________________ 19 3.2 Study area drainage ___________________________________________________ 19 3.3 Hydraulic Structures ___________________________________________________ 21 3.3.1 Copeton Dam ___________________________________________________ 21 3.3.2 Tareelaroi Weir _________________________________________________ 21 3.3.3 Boolooroo Weir __________________________________________________ 21 3.3.4 Bridges and culverts _____________________________________________ 22 3.4 Stream flow gauging stations ____________________________________________ 22 3.4.1 Available data ___________________________________________________ 22 3.4.2 Gwydir River at Gravesend ________________________________________ 24 3.4.3 Gwydir River at Pallamallawa _____________________________________ 24 3.4.4 Mehi River at Moree ______________________________________________ 25 3.4.5 Gwydir River at Yarraman Bridge ___________________________________ 26 3.4.6 Carole Creek at D/S Regulator (Bells Crossing) _______________________ 26 3.4.7 Tycannah Creek at Horseshoe Lagoon _______________________________ 28 4 XP-RAFTS Hydrology_________________________________________________ 29 4.1 Overview _____________________________________________________________ 29 4.2 Model configuration____________________________________________________ 29 4.3 Model calibration ______________________________________________________ 32 4.3.1 July 1998 event _________________________________________________ 33 4.3.2 January 2004 event ______________________________________________ 33 4.3.3 November 2011 event ____________________________________________ 34 4.3.4 February 2012 event _____________________________________________ 35 4.4 Model calibration results _______________________________________________ 37 wrmwater.com.au 1091-01-D3| 21 March 2016 | Page 3 5 Hydraulic modelling _________________________________________________ 38 5.1 Overview _____________________________________________________________ 38 5.2 Topographic data ______________________________________________________ 38 5.2.1 Available datasets _______________________________________________ 38 5.2.2 Ground survey validation _________________________________________ 40 5.2.3 Lidar dataset comparison _________________________________________ 40 5.2.4 Project DEM ____________________________________________________ 41 5.2.5 Bathymetric data ________________________________________________ 41 5.3 Model configuration____________________________________________________ 41 5.3.1 MIKE-21FM mesh properties _______________________________________ 41 5.3.2 Manning’s ‘n’ values _____________________________________________ 44 5.3.3 Model boundaries ________________________________________________ 44 5.3.4 Bridge, culvert and levee structures ________________________________ 44 5.3.5 Model parameters _______________________________________________ 48 5.4 Model calibration ______________________________________________________ 48 5.4.1 July 1998 event _________________________________________________ 48 5.4.2 January 2004 event ______________________________________________ 49 5.4.3 November 2011 event ____________________________________________ 49 5.4.4 February 2012 event _____________________________________________ 49 5.4.5 Discussion of results ______________________________________________ 50 6 Summary of findings ________________________________________________ 52 7 References ________________________________________________________ 53 Appendix A – Hydrological model calibration graphs ___________________________ 54 Appendix B – Hydrodynamic model calibration results __________________________ 67 Appendix C – SES surveyed and predicted peak water levels, February 2012 event ___ 84 Appendix D – Calibration Event Mapping _____________________________________ 93 wrmwater.com.au 1091-01-D3| 21 March 2016 | Page 4 List of Figures Figure 1.1 - The Floodplain Management Process ___________________________________ 13 Figure 1.2 – Gwydir River Catchment _____________________________________________ 14 Figure 3.1 – Drainage Characteristics Downstream of Gravesend ______________________ 20 Figure 3.2 – Copeton Dam stored water level variation, 1976 to 2015 __________________ 21 Figure 3.3 – Gwydir River and floodplain cross section at Pallamallawa gauge __________ 23 Figure 3.4 –Floodplain cross section across the Mehi River at Moree, Gwydir River at Yarraman and Carole Creek at D/S Regulator ____________________________ 24 Figure 3.5 – DPIWater rating curve and recorded gaugings, Gwydir River at Gravesend __________________________________________________________ 24 Figure 3.6 – DPIWater rating curve, MIKE-FLOOD rating curve and recorded gaugings, Gwydir River at Pallamallawa _________________________________________ 25 Figure 3.7 – DPIWater rating curve, MIKE-FLOOD rating curve and recorded gaugings, Mehi River at Moree _________________________________________________ 26 Figure 3.8 – DPIWater rating curve, MIKE-FLOOD rating curve and recorded gaugings, Gwydir River at Yarraman Bridge ______________________________________ 27 Figure 3.9 – DPIWater rating curve, MIKE-FLOOD rating curve and gaugings, Carole Creek D/S Regulator (Bells Crossing) ___________________________________ 27 Figure 3.10 – DPIWater rating curve and gaugings, Tycannah Creek at Horseshoe Lagoon _____________________________________________________________ 28 Figure 4.1 – XP RAFTS model configuration and locations of major rainfall and stream flow gauges __________________________________________________ 30 Figure 4.2 – Recorded rainfalls and discharge at Gwydir River at Gravesend and recorded rainfalls at Moree Aero, July 1998 event ________________________ 34 Figure 4.3 – Recorded rainfalls and discharge at Gwydir River at Gravesend and recorded rainfalls at Moree Aero, January 2004 event ____________________ 35 Figure 4.4 – Recorded rainfalls and discharge at Gwydir River at Gravesend and recorded rainfalls at Moree Aero, November 2011 event __________________ 36 Figure 4.5 – Recorded rainfalls and discharge at Gwydir River at Gravesend and recorded rainfalls at Moree Aero, February 2012 event ____________________ 36 Figure 5.1 – Available ground survey data extents __________________________________ 39 Figure 5.2 – MIKE-21FM Mesh regions _____________________________________________ 43 Figure 5.3 – MIKE-21FM model Manning’s ‘n’ and inflow/outflow boundaries ____________ 45 Figure B.1 – Recorded and predicted water level and discharge hydrographs at Gwydir River at Pallamallawa (418001), July 1998 event __________________ 68 Figure B.2 – Recorded and predicted water level and discharge hydrographs at Mehi River at Moree (418002), July 1998 event _______________________________ 68 Figure B.3 – Recorded and predicted water level and discharge hydrographs at Gwydir River at Yarraman (418004), July 1998 event _____________________ 68 Figure B.4 – Recorded and predicted water level and discharge hydrographs at Carole Creek at D/S regulator (418011), July 1998 event __________________ 69 Figure B.5 – Recorded and predicted water level