The Entrance Dredging Project Review of Environmental Factors
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WYONG SHIRE COUNCIL The Entrance Dredging Project Review of Environmental Factors 301015-00962(7291) – rp7291oam091112_REF_Rev0_FINAL.doc 12 November 2009 141, Walker St, North Sydney NSW 2060, Australia Tel: +61 2 8456 7200 Fax: +61 2 8923 6877 © Copyright 2009 WorleyParsons WYONG SHIRE COUNCIL THE ENTRANCE DREDGING PROJECT REVIEW OF ENVIRONMENTAL FACTORS Disclaimer This report has been prepared on behalf of and for the exclusive use of Wyong Shire Council subject to and issued in accordance with the agreement between Wyong Shire Council 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 Wyong Shire Council or WorleyParsons is not permitted. PROJECT 301015-00962(7291) - THE ENTRANCE MAINTENANCE DREDGING PROJECT REF REV DESCRIPTION ORIG REVIEW WORLEY- DATE CLIENT DATE PARSONS APPROVA APPROVAL L B Draft issued for client 30-Jun-09 N/A review O Murray G Britton G Britton B Draft issued for client 30-Jun-09 review O Murray G Britton G Britton C Draft issued for client 25-Sep-09 review O Murray G Britton G Britton 0 Final 30-Oct-09 11-Nov-09 O Murray G Britton G Britton rp7291oam091112_REF_Rev0_FINAL Page ii Rev0(12 Nov 09) WYONG SHIRE COUNCIL THE ENTRANCE DREDGING PROJECT REVIEW OF ENVIRONMENTAL FACTORS SUMMARY The natural shoaling of sands within The Entrance Channel causes the intermittent closing of the channel. This shoaling has necessitated the management of the channel through maintenance dredging to maintain tidal flows and reduce flood risks to life and property in low-lying areas of the estuary. Maintaining a more open channel prevents degradation of water quality in the Tuggerah Lakes, and preserves the existing ecological value of the estuary including the health and abundance of seagrasses, preservation of fish stocks, and the preservation of existing foreshore vegetation communities which have adapted to the this regime. The maintenance dredging was first undertaken by Wyong Shire Council in 1993 as part of the Tuggerah Lakes Restoration Project. Maintenance dredging takes approximately three to four months to complete and has been carried out on an “as needs” basis, approximately yearly since. The proposed works involve the removal of approximately 30,000m3 to 80,000m3 per annum (up to 100,000m3) of clean sands from a footprint extending from The Entrance Channel sand spit westward to Picnic Point and northward to the northern end of the Terilbah Channel. The sand deposited in the channel, while of both marine and alluvial sources, is considered compatible with the sands of adjacent beaches which are susceptible to erosion. The dredging allows for a sustainable and local supply of material suitable for nourishment of the depleted beaches including North Entrance Beach and the estuary eastern beach adjacent to Karagi Park Foreshore. Nourishment of these areas minimises the potential for erosion to the adjacent dunes and reduction of impacts to associated ecosystems, infrastructure and property. Some minor and temporary impacts may occur during the dredging activity. However, based on the findings of this REF and associated investigations, it is considered that provided the safeguards recommended in this document are implemented, any impacts would be outweighed by the long-term beneficial impacts provided by the dredging and beach nourishment activities. Survey and monitoring programs have also been recommended to ensure the ongoing protection of the environment and to allow for the identification of any improvements that may be incorporated into future dredging campaigns. Approvals required to carry out the proposed works have been identified as follows: Department of Primary Industries (Fisheries): o permit to harm marine vegetation under Section 205 of the Fisheries Management Act 1979; and Department of Lands: o licence for the use of Crown land under Section 34A of the Crown Lands Act 1989. An Environmental Protection Licence (EPL3200) is currently in place for the dredging and beach nourishment works. The EPL is continuous and independent of any other approvals. The EPL does not require any renewal or modifications for the works proposed in this REF Council is seeking rp7291oam091112_REF_Rev0_FINAL Page iii Rev0 (12 Nov 09) WYONG SHIRE COUNCIL THE ENTRANCE DREDGING PROJECT REVIEW OF ENVIRONMENTAL FACTORS permission for a temporary dredge haul-out area in Terilbah Reserve. The haul-out area will be considered in a separate process to this REF and would involve an amendment to the existing licence. rp7291oam091112_REF_Rev0_FINAL Page iv Rev0 (12 Nov 09) WYONG SHIRE COUNCIL THE ENTRANCE DREDGING PROJECT REVIEW OF ENVIRONMENTAL FACTORS CONTENTS 1. INTRODUCTION ................................................................................................................1 1.1 Background.........................................................................................................................1 1.2 Site Location .......................................................................................................................3 1.3 Scope of Works...................................................................................................................3 2. DESCRIPTION OF THE EXISTING ENVIRONMENT .......................................................6 2.1 Sediment Dynamics............................................................................................................6 2.2 Hydraulics ...........................................................................................................................6 2.3 Water Quality ......................................................................................................................8 2.4 Bed Sediments....................................................................................................................8 2.5 Condition of the Beaches..................................................................................................11 2.6 Land and Waterway Use ..................................................................................................11 2.6.1 Zoning ..................................................................................................................11 2.6.2 Recreational and Commercial Uses ....................................................................12 2.7 Ecology .............................................................................................................................12 2.7.1 Flora .....................................................................................................................13 2.7.2 Fauna...................................................................................................................16 2.7.3 Ecological Communities.......................................................................................19 3. DESCRIPTION OF THE PROPOSED WORKS...............................................................20 3.1 Proposed Dredging Works................................................................................................20 3.1.1 Production Rates and Quantities .........................................................................21 3.2 Proposed Beach Nourishment..........................................................................................21 3.3 Rehabilitation of Work Areas ............................................................................................26 3.4 Plant and Equipment ........................................................................................................26 3.4.1 Dredging and Beach Nourishment.......................................................................26 3.5 Project Timing and Duration .............................................................................................27 4. PROJECT JUSTIFICATION AND CONSIDERATION OF ALTERNATIVES ...................29 4.1 Alternatives to the Project Proposal..................................................................................29 rp7291oam091112_REF_Rev0_FINAL Page v Rev0 (12 Nov 09) WYONG SHIRE COUNCIL THE ENTRANCE DREDGING PROJECT REVIEW OF ENVIRONMENTAL FACTORS 4.1.1 Alternatives to Dredging.......................................................................................29 4.1.2 Alternative Placement Options.............................................................................29 4.1.3 The Do-Nothing Option ........................................................................................30 4.2 Ecologically Sustainable Development.............................................................................30 4.3 Justification for the Project................................................................................................32 5. ENVIRONMENTAL PLANNING FRAMEWORK ..............................................................34 5.1 Commonwealth Approvals Process..................................................................................34 5.2 NSW Planning and Approvals Process ............................................................................34 5.3 Other Relevant State Legislation......................................................................................35 5.4 Licences and Approvals....................................................................................................37 5.5 Other Relevant Plans........................................................................................................37