FAR NORTH QUEENSLAND PORTS CORPORATION Cairns Port Long Term Management Plan Dredging and Dredge Spoil Management 301001-00680 – 301001-00680-00-EN-REP-0001 12 May 2010 Infrastructure & Environment Level 3, 80 Albert Street Brisbane QLD 4000 Australia Telephone: +61 7 3221 7444 Facsimile: +61 7 3221 7791 www.worleyparsons.com ABN 61 001 279 812 © Copyright 2010 WorleyParsons FAR NORTH QUEENSLAND PORTS CORPORATION CAIRNS PORT LONG TERM MANAGEMENT PLAN DREDGING AND DREDGE SPOIL MANAGEMENT SYNOPSIS This Long Term Management Plan (LTMP) outlines the regulatory processes followed in obtaining approval for annual routine maintenance dredging, including management responsibilities. Existing background information relating to the identification of suitable disposal strategies has been revised. Roles and responsibilities of the Technical Advisory and Consultative Committee (TACC) are outlined and a process of involvement tabled. The LTMP also outlines the predicted volumes of maintenance dredging material and describes the processes by which dredging and disposal will be carried out. Existing environmental conditions, significant species, and habitats of concern are also described from a range of regional and specific studies undertaken by the Port over many years. Analysis of the potential risks associated with routine annual maintenance dredging and disposal has been completed, and a series of management strategies developed, via which these affects can be monitored and controlled. Disclaimer This report has been prepared on behalf of and for the exclusive use of Far North Queensland Ports Corporation, and is subject to and issued in accordance with the agreement between Far North Queensland Ports Corporation and WorleyParsons. WorleyParsons accepts no liability or responsibility whatsoever for it in respect of any use of or reliance upon this report by any third party. Copying this report without the permission of Far North Queensland Ports Corporation or WorleyParsons is not permitted. PROJECT 301001-00680 - CAIRNS PORT LONG TERM MANAGEMENT PLAN REV DESCRIPTION ORIG REVIEW WORLEY- DATE CLIENT DATE PARSONS APPROVAL APPROVAL 5 Issued for use 12-05-10 A Fletcher J Kennedy V Seto T Koskela g:\301001\00680 prjt - ocean disp s.svy & ltmp\2.0 reports\ltdmp\final for gbrmpa\301001-00680-3g1002-rep- 0001 ltmp rev 5.doc Document No : 301001-00680-00-EN-REP-0001 Page ii FAR NORTH QUEENSLAND PORTS CORPORATION CAIRNS PORT LONG TERM MANAGEMENT PLAN DREDGING AND DREDGE SPOIL MANAGEMENT CONTENTS 1. INTRODUCTION ................................................................................................................2 1.1 Cairns Port ..........................................................................................................................2 1.2 Long Term Management Plan ............................................................................................6 1.2.1 Objectives of this Plan ...........................................................................................6 2. MANAGEMENT FRAMEWORK .........................................................................................8 2.1 Approvals ............................................................................................................................8 2.2 Technical Advisory Consultative Committee ....................................................................10 2.3 Existing Approvals and Conditions ...................................................................................11 3. DREDGING AND DISPOSAL...........................................................................................12 3.1 History of Dredging and Disposal Works..........................................................................12 3.1.1 Capital Dredging ..................................................................................................12 3.1.2 Maintenance Dredging.........................................................................................12 3.1.3 Outer and Inner Shipping Channel and Associated Swing Basins......................13 3.1.4 Inner Port (Main Wharves 1-12), Marlin Marina, CFB1 and CFB2......................13 3.1.5 HMAS Cairns Navy Base.....................................................................................13 3.1.6 Historical Dredging Volumes................................................................................14 3.2 Dredging Requirements 2010-2020..................................................................................16 3.2.1 Dredge Methods ..................................................................................................20 3.2.2 Proposed Dredge Schedule.................................................................................22 3.2.3 Future Dredge Requirements ..............................................................................23 3.3 Waste Prevention..............................................................................................................23 3.4 Disposal Options Review..................................................................................................25 3.4.1 Offshore Spoil Disposal Location and Capacity...................................................26 4. DREDGE SPOIL CHARACTERISTICS............................................................................30 4.1.1 Physical Characteristics.......................................................................................30 4.1.2 Chemical Contaminant Characteristics................................................................32 g:\301001\00680 prjt - ocean disp s.svy & ltmp\2.0 reports\ltdmp\final for gbrmpa\301001-00680-3g1002-rep-0001 ltmp rev 5.doc 301001-00680 : 301001-00680-00-EN-REP-0001 Rev 5 : 12 May 2010 Page i FAR NORTH QUEENSLAND PORTS CORPORATION CAIRNS PORT LONG TERM MANAGEMENT PLAN DREDGING AND DREDGE SPOIL MANAGEMENT 5. EXISTING ENVIRONMENT .............................................................................................43 5.1 Land Use and Management .............................................................................................43 5.1.1 Management Areas..............................................................................................43 5.2 Physical Environment .......................................................................................................45 5.2.1 Coastal processes ...............................................................................................45 5.2.2 Trinity Inlet and Trinity Bay ..................................................................................47 5.2.3 Spoil Ground ........................................................................................................47 5.2.4 Water Quality .......................................................................................................48 5.3 Cultural Values..................................................................................................................53 5.3.1 Locations of Value ...............................................................................................54 5.3.2 Marine Sites of Value...........................................................................................55 5.4 Marine Habitats.................................................................................................................56 5.4.1 Seagrass..............................................................................................................56 5.4.2 Mangroves ...........................................................................................................60 5.4.3 Intertidal Soft Sediment........................................................................................61 5.4.4 Subtidal Soft Sediment ........................................................................................61 5.4.5 Spoil Ground Site Characteristics........................................................................61 5.5 Species of Conservation Significance ..............................................................................62 5.6 Introduced Marine Pests...................................................................................................71 6. IMPACTS OF DREDGING AND DISPOSAL....................................................................76 6.1 General .............................................................................................................................76 6.2 Water Quality ....................................................................................................................81 6.2.1 Turbidity and Suspended Solids ..........................................................................81 6.2.2 Nutrients...............................................................................................................82 6.2.3 Toxicants..............................................................................................................83 6.3 Sediment Quality at the Spoil Ground ..............................................................................83 6.4 Benthic Flora and Fauna ..................................................................................................84 g:\301001\00680 prjt - ocean disp s.svy & ltmp\2.0 reports\ltdmp\final for gbrmpa\301001-00680-3g1002-rep-0001 ltmp rev 5.doc 301001-00680 : 301001-00680-00-EN-REP-0001 Rev 5 : 12 May 2010 Page ii FAR NORTH QUEENSLAND PORTS CORPORATION CAIRNS PORT LONG TERM MANAGEMENT PLAN DREDGING AND DREDGE SPOIL MANAGEMENT 6.4.1 Mangroves