Proposed Katherine to Gove Gas Pipeline Draft Environmental Impact Statement Appendix C Vegetation & Flora Study KGGP Vegetation & Flora Study Final Pacific Aluminium (Alcan Gove Pty Limited) 2013 1. www.ecoz.com.au Report Title Document Control Record Prepared by: Will Riddell Approved by: Jeff Richardson Position: Environmental Consultant Position: Principal Consultant Signed: Signed: Date: 08/02/2013 Date: 08/02/2013 REVISION STATUS Revision No. Description of Date Comment Approved Revision A Internal review 31/01/2013 JS 0 First Issue 08/02/2013 JR Recipients are responsible for eliminating all superseded documents in their possession. Document No: EZ12048-C0301-EIA-R- Catalogue D000029177 0002 Number EcOz Pty Ltd. EcOz Environmental Services ABN: 81 143 989 039 Winlow House, 3rd Floor 75 Woods Street DARWIN NT 0800 PO Box 381, Darwin NT 0800 Telephone: +61 8 8981 1100 Facsimile: +61 8 8981 1102 Email: [email protected] Internet: www.ecoz.com.au RELIANCE, USES and LIMITATIONS This report is copyright and is to be used only for its intended purpose by the intended recipient, and is not to be copied or used in any other way. The report may be relied upon for its intended purpose within the limits of the following disclaimer. This study, report and analyses have been based on the information available to EcOz Environmental Services at the time of preparation. EcOz Environmental Services accepts responsibility for the report and its conclusions to the extent that the information was sufficient and accurate at the time of preparation. EcOz Environmental Services does not take responsibility for errors and omissions due to incorrect information or information not available to EcOz Environmental Services at the time of preparation of the study, report or analyses. Client: Pacific Aluminium ii Doc Title: KGGP Vegetation & Flora Study Final Executive Summary This report investigates the existing vegetation and flora and potential environmental impacts of the construction and operation of a gas pipeline and associated above-ground facilities to transport gas from south of Katherine to the Alcan Alumina Refinery on the Gove Peninsula in north-east Arnhem Land. The report is and update of a previous flora and vegetation report, prepared in 2004, that was part of the previous Trans Territory Pipeline (TTP) project. EcOz Environmental Services has been contracted by Pacific Aluminium (Alcan Gove Pty Limited) to update the 2004 report by including those findings and assessments relevant to the KGGP and to assess the relevance of any new site records that have been documented in the period since 2004 through new database searches. The vegetation traversed by the pipeline corridor is characterised by 12 Vegetation Units within eight Broad Vegetation Groups (BVG’s) dominated by Eucalyptus miniata and E. tetrodonta, which are the most common vegetation associations in the Top End of the Northern Territory, characterise the majority of the pipeline corridor. Woodlands dominated by associations of Eucalyptus tectifica and Corymbia spp. are the next most common vegetation in the project area. Vegetation communities of conservation significance including riparian corridors, wetlands (swamps and floodplains), monsoon vine forests and sandstone communities occur in proximity to the project area. The locations and characteristics of communities of conservation significance that could be affected by construction and operation are summarised with recommendations on management and mitigation measures to minimise impacts. One Threatened ecological community, the Arnhem Plateau Sandstone Shrubland Complex, potentially occurs within the KGGP project area. However, mapping of this community suggests that it is unlikely to occur. A desktop review and the 2003/04 flora survey revealed that a total of 26 weed species of concern potentially occur within the KGGP project area. Eighteen of the species identified in are declared weeds under the NT Weeds Management Act and six are classified as Weeds of National Significance (WONS). Two Threatened plant species potentially occur within the KGGP corridor: Pternandra coerulescens Sticherus flabellatus var. compactus P. coerulescens has previously been recorded from a location 750m south-east of where the pipeline corridor will cross the Latram River (KP572), however, surveys of the Latram River at the proposed pipeline crossing did not identify any specimens of this species. Horizontal Direction Drilling (HDD) techniques are proposed for constructing the Latram River crossing, therefore, it is considered unlikely that the project will impact on P. coerulescens. Sticherus flabellatus var. compactus occurs within a 10km buffer of the project area but not the KGGP route or associated 30m Right of Way (ROW). The project is therefore unlikely to impact on this species. The potential impacts of the proposed KGGP project on vegetation and flora have been minimised during the design phase of the project by locating the pipeline corridor and permanent and temporary above ground infrastructure so that vegetation communities of high conservation value, and\or that play a regional role in maintaining ecosystems, are avoided. In addition, horizontal directional drilling construction techniques have been recommended for constructing a number of the major watercourse crossings in order to avoid ecologically important riparian vegetation corridors and minimise the potential for downstream impacts. By taking into account the regional role of vegetation in maintaining ecosystem processes, and the conservation values of vegetation communities and flora, during the design process, the potential impacts of the project Client: Pacific Aluminium iii Doc Title: KGGP Vegetation & Flora Study Final will be minimised as long as appropriate management measures are implemented for the duration of construction and operation. The main potential impacts of construction and operation of the proposed pipeline are: • clearing of vegetation – clearing of vegetation will be required for the pipeline corridor, above ground facilities such as compressor stations, access tracks, and temporary facilities such as construction camps, borrow pits and laydown areas; • degradation of sensitive vegetation communities and habitats – this could occur through direct or indirect disturbance of communities as a result of inadequate management of construction and operation activities near to sensitive areas; • introduction and spread of exotic species – disturbance and increased access during construction and operation may introduce and spread weed species with associated potential for adverse impacts on the ecological integrity of vegetation communities. The potential impacts of construction and operation are discussed in detail in this report and management measures to mitigate the adverse impacts of the project are recommended for before, during and after construction. Additional measures for minimisation of site specific impacts should be developed following determination of the final design specifications. Client: Pacific Aluminium iv Doc Title: KGGP Vegetation & Flora Study Final Table of Contents 1 Introduction .............................................................................................................................................1 2 Statutory Obligations ..............................................................................................................................2 2.1 Native Vegetation Clearing .................................................................................................................2 2.2 Protected Vegetation Communities and Flora Species ......................................................................2 2.3 Management of Weeds .......................................................................................................................3 3 Methodology ............................................................................................................................................4 3.1 Desktop Review ..................................................................................................................................4 3.2 Vegetation Descriptions ......................................................................................................................4 3.3 Field Surveys ......................................................................................................................................5 3.4 Assessment of Conservation Significance .........................................................................................6 3.5 Limitations ...........................................................................................................................................6 4 Vegetation Communities and Flora Species ........................................................................................7 4.1 Field Survey Results ...........................................................................................................................7 4.2 Vegetation Communities in the Project Area ......................................................................................7 4.3 Flora Species ................................................................................................................................... 11 4.4 Weeds .............................................................................................................................................. 11 5 Conservation Significance .................................................................................................................