Floodplain Management Plan
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Caroona – Breeza Floodplain Management Plan June 2006 Acknowledgments This project has been funded by the Commonwealth Natural Heritage Trust and State Government, with involvement of Department of Natural Resources, the Caroona - Breeza landholders and the community. Caroona – Breeza Floodplain Management Plan August 2005 © NSW Department of Natural Resources 2006 www.naturalresources.nsw.gov.au ISBN 0 7347 5656 9 Reprint with corrections June 2006 Disclaimer While every reasonable effort has been made to ensure that this document is correct at the time of printing, the State of New South Wales, its agents and employees, disclaim any and all liability to any person in respect of anything or the consequences of anything done or omitted to be done in reliance upon the whole or any part of this document. Caroona – Breeza Floodplain Management Plan June 2006 TABLE OF CONTENTS Page No. PREAMBLE ...................................................................................................................................................... iii 1.0 INTRODUCTION......................................................................................................................................1 1.1 Overview ..................................................................................................................................................1 1.2 Vision Statement ......................................................................................................................................1 1.3 Objectives.................................................................................................................................................1 1.4 The Study Area ........................................................................................................................................1 1.4.1 Overview ...................................................................................................................................1 1.4.2 Flooding.....................................................................................................................................2 2.0 LEGISLATION AND POLICY OVERVIEW .............................................................................................5 2.1 The Flood Prone Land Policy...................................................................................................................5 2.2 Water Act 1912 and Water Management Act 2000 .................................................................................5 2.3 Additional Floodplain Management Controls ...........................................................................................5 2.4 Relevant Management Plans ...................................................................................................................5 3.0 HYDRAULIC ASSESSMENT OVERVIEW..............................................................................................6 3.1 Overview ..................................................................................................................................................6 3.2 Modelling Procedure ................................................................................................................................6 4.0 FLOODPLAIN MANAGEMENT PRINCIPLES........................................................................................7 5.0 DEVELOPMENT ASSESSMENT CRITERIA..........................................................................................8 5.1 Overview ..................................................................................................................................................8 5.2 Adopted Criteria .......................................................................................................................................8 5.2.1 Design Flood Event...................................................................................................................8 5.2.2 Historical (for existing flood control works only)........................................................................8 5.2.3 Socio-Economic ........................................................................................................................8 5.2.4 Ecological..................................................................................................................................9 5.2.5 Flooding Behaviour ...................................................................................................................9 6.0 FLOODPLAIN MANAGEMENT ISSUES ..............................................................................................11 6.1 General...................................................................................................................................................11 6.2 Staging ...................................................................................................................................................11 6.3 General Issues .......................................................................................................................................12 6.3.1 Unauthorised Works................................................................................................................12 6.3.2 Supply Channels .....................................................................................................................12 6.3.3 Probable Maximum Flood (PMF) ............................................................................................12 6.4 Specific Issues .......................................................................................................................................13 7.0 THE FMP FLOODWAY NETWORK......................................................................................................19 8.0 ENVIRONMENTAL ASSESSMENT ......................................................................................................21 8.1 Overview ................................................................................................................................................21 8.2 Environmental Assessment Summary ...................................................................................................21 8.3 Instream Works ......................................................................................................................................22 8.4 Downstream Floodplains........................................................................................................................22 8.5 SWMOP Target NO. 25..........................................................................................................................23 Department of Natural Resources Caroona – Breeza Floodplain Management Plan June 2006 9.0 RELATED ISSUES AND MANAGEMENT PRACTICES......................................................................25 9.1 Landuse Management............................................................................................................................25 9.1.1 General....................................................................................................................................25 9.1.2 Best Management Practices ...................................................................................................25 9.1.3 Specific Limited Landuse Areas..............................................................................................25 9.2 Maintenance of Floodways ....................................................................................................................26 9.3 Monitoring...............................................................................................................................................26 9.3.1 Flood Monitoring .....................................................................................................................26 9.3.2 FMP Review............................................................................................................................27 9.4 Riparian Buffer Zones ............................................................................................................................27 9.5 Road Raising..........................................................................................................................................27 10.0 IMPLEMENTATION STRATEGY ..........................................................................................................29 10.1 General...................................................................................................................................................29 10.2 Performance Assessment ......................................................................................................................29 10.3 Approval of Flood Control Works ...........................................................................................................29 10.3.1 General....................................................................................................................................29 10.3.2 Works That Require Approval.................................................................................................30 10.3.3 Applying for Approval ..............................................................................................................30 10.3.4 Determination Process............................................................................................................31 10.3.5 Possible