4.0 Environmental Impact Assessment

4.0 Environmental Impact Assessment

4.1 Introduction

The information provided in the final EIS has been assessed and then used, along with submissions from advisory bodies and public comment on the draft EIS, to determine the adequacy of the information provided by the proponent and the accuracy and acceptability of predicted impacts and safeguards. The outcome of this assessment is that the proposal can be implemented without significant environmental impacts. Specific recommendations for mitigation and monitoring of impacts are made.

It is acknowledged that during implementation of proposals outlined in the EIS, flexibility is necessary and desirable to allow for minor and non-substantial changes to the design and specifications which have been examined as part of this assessment. It is considered that subsequent statutory approvals for this project could make provisions for such changes, where it can be shown that the changes are not likely to have a significant effect on the environment.

It is important for interpretation purposes that the recommendations are not considered in isolation, as the text identifies concerns, suggestions and undertakings associated with the project.

Subject to decisions which permit the project to proceed, the primary recommendation of this assessment is:

Recommendation 1

The proponent shall ensure that the proposal is implemented in accordance with the environmental commitments and safeguards identified in the Darwin LNG Plant draft Environmental Impact Statement, as modified in the Supplement to the draft EIS and as recommended in this assessment report.

4.2 Issues raised in Submissions

The major environmental issues identified with the development and operation of the LNG Plant and Pipeline were:

1. plant location and expansion;
2. planning, land use concepts and cumulative impacts;
3. access road;
4. pipeline construction;
5. atmospheric emissions;
6. water quality (including potential for increased turbidity,sedimentation, acid leachate, introduction of exotic marine pests and stormwater runoff/drainage);
7. flora, fauna and habitat management;
8. waste management;
9. heritage, cultural and social values;
10. monitoring requirements; and
11. hazard and risk assessment.

The Supplement to the draft EIS contains the proponent's responses to issues raised in the 12 submissions. A summary of these issues can be found in Appendix 2 of this Assessment Report. Many issues have been dealt with satisfactorily in the Supplement and do not require further discussion, however major issues are addressed below.

Several submissions raised the issue of planning in the Darwin region. This issue is outside the scope of the EIS, however it is a matter that the NT Government is addressing. The NT Coastal Management Policy is presently being reviewed with the aim of identifying detailed actions for its implementation. An issue identified during the review process is the need for an integrated NT Mangrove Management Strategy. This strategy will provide a means to address land use conflicts within Darwin Harbour as they relate to mangroves. The Strategy is expected to be developed by 1999 (DLPE, 1997).

In relation to the present project, The Darwin Regional Land Use Structure Plan 1990 (NT DLH, 1990) has identified Middle Arm Peninsula as suitable for future industrial development and, as such, it is an appropriate location for the proposed project. Also taken into account in the Plan is the commitment to preserve 80% of the productivity of the mangroves of Darwin Harbour. At present, less than 2% of mangroves have been cleared in Darwin Harbour (DLPE, 1997). The area of mangroves that would be affected by this project constitutes another 0.02%. Therefore, in terms of mangrove productivity, it is considered that the project would not compromise the integrity of Darwin Harbour mangroves as a whole.

The NT Government also recognises the importance of the dry rainforest habitat identified in the EIS as a significant issue at a regional level. While Middle Arm Peninsula has been identified as an industrial location, Land Use Objectives are at present being developed, which will identify specific zones for the area and will take into account the need to protect this, and any other, significant vegetation types within the Darwin catchment. Under the current Litchfield Shire Control Plan the site will require rezoning for the proposal to proceed. In addition, there will be uses that will be precluded from areas adjacent to the plant due to the requirement for a safety buffer zone around the plant.

Two submissions were received which raised issues related to East Timor. These issues were also outside the scope of this assessment, however they were addressed by the proponent in the Supplement (Appendix 7 of the Supplement).

The following issues are grouped according to the various stages at which environmental safeguards may be implemented within the planning framework of a project. In this case, the stages are: Project Design Phase, Construction Phase, Operational Phase, Hazard and Risk Assessment, Decommissioning and Monitoring. Issues associated with construction of the access road, now the responsibility of the NT Government, are dealt with at the end of this section.

4.3 Environmental Management Plan

The environmental commitments and safeguards made by the proponent have been summarised in Table 7.1 of the draft EIS and on pages 115 - 118 of the Supplement to the draft EIS. A summary table, combining commitments outlined in both the draft EIS and the Supplement are included in this report at Appendix 3.

One of the major commitments is the preparation of an Environmental Management Plan (EMP). The EMP will comprise both a Construction Management Plan (CMP) and an Operations Management Plan (OMP) and will cover both the LNG plant and pipeline, from the commencement of construction to decommissioning.

The EMP will outline specific management responses to environmental impacts and issues identified during the assessment process, and is intended to provide detailed plans of action to assist in the avoidance or mitigation of identified adverse impacts. The stated objectives of the EMP are to:

• ensure that construction activities are undertaken in an appropriate manner and that impacts on the environment are minimised and monitored;
• ensure that impacts associated with the operating phase of the development are minimised and monitored; and
• minimise the risk of potential effects from unexpected incidents, such as oil spills and ensure that appropriate contingency plans are in place in the event of such incidents.

The major components of the EMP include specific action plans, environmental monitoring programs, compliance auditing and reporting commitments, emergency response procedures, and an outline of decommissioning proposals.

The draft EIS provided an outline of the proposed components of the EMP, which highlight the specific areas to be addressed and mitigation measures. The Supplement provided additional detail and a consolidated list of major commitments by the proponent for the protection of the environment. The major areas to be addressed in the CMP are plant site construction, workforce management, plant site waste management, dredging and spoil disposal management, and pipeline construction. The major areas to be addressed in the OMP are stated as including plant site management, workforce management, plant waste management and ship loading management.

The environmental monitoring programmes committed to by the proponent can be found in Appendix 3 of this report and are summarised below:

• occurrence of weeds and feral animals;
• occurrence of potential biting insect breeding sites;
• extent of dispersion of water turbidity during pipeline shore construction and dredging;
• turbidity effects on corals at Channel Island;
• dredging effects on corals at Wickham Point;
• waste disposal;
• effect of construction activities and plant site operations on mangrove and rainforest vegetation adjacent to the site;
• wastewater discharges;
• atmospheric emissions;
• accumulation of heavy metals and TBT in sediments and selected biota in the vicinity of the shiploading facility; and
• introduced marine organisms.

The NT Government understands that the EMP will be the major vehicle for implementing the proponent's commitments and environmental protection measures. It is therefore important that the EMP is subject to review before finalisation. In addition, as the EMP is intended to be a working document, it will require continual review in the light of operational experience and changed circumstances.

Recommendation 2

In preparing the Environmental Management Plan the proponent shall include any additional measures for environmental protection and monitoring contained in recommendations made by the Commonwealth and Northern Territory Governments with respect to the proposal. The EMP shall be referred to Environment Australia and relevant NT agencies for review prior to finalisation, after which it shall become a public document. The EMP shall form the basis for any approvals and licences issued under the forthcoming Waste Management and Pollution Control Act.

4.4 Project Design Phase

4.4.1 LNG Plant expansion

While the Draft EIS was written for an LNG plant with a capacity of 3 million tonnes per annum (MTPA), one of the site selection criteria was that the site must be at least 150 ha in area to allow for potential expansion to 9 MTPA. It is acknowledged that some of the environmental impacts would remain the same, particularly those related to the construction stages, however many impacts would increase. These include the amount of vegetation clearance, increased atmospheric emissions and other waste products and the volume of shipping movements.

In order to provide relevant recommendations in this assessment report, an indication of the impacts from an expanded plant was necessary. As a result of the request for more information about the expansion, the Supplement details several project modifications to the original layout of the plant, to accommodate any future expansion. According to the proponent, the redesigned layout will provide for the most efficient expansion of the plant, with all existing facilities being utilised and removing the need for the construction of additional facilities.

The redesigned facility for the initial 3 MTPA capacity will now occupy 68 ha as against the originally proposed 61 ha. However, the 9 MTPA plant would require only 100 ha as against the 150 ha required before being redesigned.

This report assesses the 3 MTPA layout as designed in the final EIS. It is considered that the increase in the footprint for the 3 MTPA plant would be offset by the savings on footprint size for the 9 MTPA plant, in terms of vegetation loss. This issue will be dealt with further under Flora, Fauna and Habitat Management (Section 4.5.3).

While it appears that the site is suitable for future expansion, the EIS provides only a brief assessment of impacts associated with expansion. As the proponent has noted in Appendix 4 of the Supplement, any expansion will be subject to further assessment under the NT Environmental Assessment Act 1982.

Recommendation 3

In the event that an expansion of the LNG Plant is proposed, the revised project design shall be submitted to the NT Government for further assessment under the NT Environmental Assessment Act 1982.

4.4.2 Pipeline design and alignment

The pipeline is to be installed over approximately 500 km of seabed to the north west of Darwin traversing 4 jurisdictions (Joint Authority of the Zone of Cooperation, Commonwealth Government, NT Government and WA Government). While the general pipeline route has been selected, the final detailed alignment is yet to be determined. The proponent has specified a number of authorities to be consulted in finalising the route and criteria to be used to minimise environmental impacts. The EIS states that one of the environmental criteria to be taken into account in aligning the pipeline will be avoidance of areas of conservation significance. An additional authority to be consulted in respect to these areas is the Parks and Wildlife Commission of the NT. In addition, the NT Department of Primary Industry and Fisheries requests that avoidance of areas significant to fishing activity should be added to the list of environmental criteria.

It is noted that discussions have taken place between the Department of Defence and the proponent with respect to the offshore military exercise area and that this area will now be avoided.

Adequacy of Description of Existing Environment

The existing offshore environment in the vicinity of the pipeline route has been briefly highlighted in Section 6.2, and is presented in full in Appendix D, of the draft EIS. Several areas have been identified as of environmental or conservation significance in the vicinity of the pipeline. All of these areas are at some distance from the proposed route and will not be affected by the construction and operation of the pipeline.

As noted in Section 6.2.2.3 of the draft EIS, the limited surveys undertaken indicate that the offshore seabed has only a sparse flora/fauna population, with shoal areas supporting corals, sponges and macro algae. The proponent states that none of the seabed communities along the seabed route have been identified as being of local or regional conservation significance. The results of the proponent's initial investigations concur with the information gained from several completed surveys conducted by other members of the offshore exploration and production industry.

The proponent has committed to undertaking detailed seabed evaluations along the preferred pipeline route in consultation with the relevant agencies (see above).

The proponent has described the existing marine environment within Darwin Harbour in Section 6.3.2 and Appendix K of the draft EIS. There are a variety of complex habitat types in the harbour. The most obvious being the extensive intertidal mud flats and mangroves. Coral assemblages exist in several areas within the harbour, however they occur as scattered coral colonies and do not form reefs. No dense seagrasses are known to occur in the harbour. Intertidal and subtidal benthic fauna were also surveyed (appendix K of the draft EIS). The intertidal fauna comprised crustaceans and mudskippers while subtidally, the benthic fauna comprised mainly amphipod crustaceans and polychaete worms. Large, mobile marine fauna were not surveyed, however crocodiles, dolphins and some species of turtles are known to occur in the harbour.

The description of the existing environment in the vicinity of the pipeline is considered to be adequate.

Evaluation of Potential Impacts and Safeguards

It is noted that the final pipeline alignment is yet to be determined. While the route is generally considered to be acceptable from an environmental viewpoint, detailed route selection should be subject to further consultation with the appropriate agencies. Agencies should also be consulted with regard to the types and timing of surveys to be conducted as part of the seabed evaluation.

A more comprehensive evaluation of the potential impact and safeguards related to pipeline construction can be found under section 4.5.1.

Recommendation 4

The final route of the subsea pipeline and any associated surveys, studies and consultations undertaken to determine the final alignment, shall be made available to relevant NT agencies for comment. In particular, the proponent shall demonstrate that the route has been selected to avoid:

• areas requiring blasting or substantial preparatory earthworks;
• areas of recreational or conservation significance;
• areas of significance to fishing activity;
• areas which may be inhabited by rare or endangered species;
• protected maritime heritage areas;
• shallow water depths, or shoals, where corals or other significant habitat may exist; and
• marine Aboriginal sacred sites.

The draft EIS notes that the main heritage concerns associated with the pipeline route occur within Darwin Harbour. The proposed pipeline will run near World War II ship wrecks (USAT Mauna Loa and USAT Meigs) in Darwin Harbour and the wreck of the Japanese submarine I-124 offshore. The USAT Mauna Loa, USAT Meigs and the SS Ellengowan are declared as heritage places under the NT Heritage Conservation Act 1991. The I-124 is a war grave declared under the Commonwealth Historic Shipwrecks Act 1976. It is a restricted area and entry or mooring of ships, diving and other underwater activities are prohibited within a 500 m zone centred around 12o7'S, 130o7'E.

There are also a large number of poorly recorded, or unrecorded, wrecks in Darwin Harbour. The Northern Territory Shipwreck database held at the Department of Arts and Museums has recorded a total of 73 wreck sites in Darwin Harbour. Several of these historic and archaeologically significant shipwrecks are not declared protected sites, however, all these wrecks are popular diving and fishing locations.

In the Supplement, the proponent noted the additional information provided in submissions and stated that the final pipeline route would be selected to avoid protected and other identified maritime heritage sites, as far as possible. The proponent states that, prior to finalising the route, a detailed survey of the proposed route will be undertaken, using magnetometer and side scan sonar to search for potential wrecks. Significant magnetic anomalies will be recorded and checked. This work is proposed to be undertaken in close consultation with appropriate staff of the Department of Arts and Museums.

Recommendation 5

The proposed pipeline alignment survey shall be undertaken in close consultation with relevant Northern Territory agencies. In the event that new wrecks or other historical material are found, the proponent shall advise the Heritage Conservation Branch of the DLPE.

4.4.3 Water quality

Dredging and spoil disposal

With a view to removing the need for the temporary spoil disposal site, the proponent has conducted a preliminary review of the dredging and spoil disposal options. The preferred option is to coordinate dredging operations with the Department of Transport and Works and to dispose of all suitable fill material at the East Arm Port reclamation site. Other options to be investigated include sidecasting spoil to the floor of Middle Arm channel and relocation of the spoil to another temporary reclamation site on Wickham Point.

A further modification to the dredging operations involves the excavation of material from the construction dock approaches. As the cutter suction dredge proposed for the dredging of the turning basin is too big to operate in the shallow waters of the eastern side of Wickham Point, several other options are under investigation including using a smaller cutter suction dredge, a clam shell grab dredge and constructing the channel by excavator at low tide.

Adequacy of Description of Existing Environment

Results from a preliminary geotechnical analysis of the areas requiring dredging indicate that most of the spoil will be suitable as fill material. The turning basin will be dredged to a level of RL 13 m (CD), involving removal of an estimated 150,000 m3 of spoil, comprising approximately 30% gravel, 40% sand, 10% silt and 20% clay. Dredging of the construction dock would remove an estimated 50,000 m3 of spoil (10% gravel, 40% sand, 20% silt, and 30% clay), while dredging for the pipeline shore crossing would involve removal of about 14,000 m3 of soil and weathered rock.

Two locations suitable for a temporary reclamation area have been identified at Wickham Point. These are at the eastern end of the loading jetty and groyne, and on the western side of the construction dock. While these locations are located partially in mangroves, the proponent notes that they have advantages in that the walls of the groyne or construction dock can be incorporated as bunds, transport of spoil to the sites would be facilitated by their relative proximity, the piping distance for discharge water would be minimal, and seepage flows would be directly to the adjacent tidal areas. In addition, access roads would not be required for these sites, and the potential exists to use them for future laydown areas.

Evaluation of Potential Impacts and Safeguards

Direct pumping or disposal of spoil as fill for the East Arm Port development is the preferred outcome as it minimises environmental impacts associated with dredging, however it is acknowledged that temporary storage of spoil may be required. A temporary reclamation site in either of the two locations identified in the EIS has the potential to adversely affect mangrove communities. If the outcome of the dredging evaluation requires a temporary reclamation site, monitoring of the decant water will be essential. This monitoring would be in addition to any monitoring deemed necessary from the dredging evaluation.

If the outcome of the dredging evaluation suggests that the preferred action is to sidecast spoil, further modelling would be necessary to show that this can be done without significant impacts on water quality and coral assemblages. In addition, a reactive monitoring program would be required to ensure that turbidity impacts are as predicted, and to allow dredging methods to be modified if required.

As there are a number of environmental impacts associated with dredging in Darwin Harbour, it is crucial that the dredging methods are determined prior to commencement of construction. In addition, an assessment of the associated environmental impacts must be undertaken and measures to mitigate the impacts determined, including protection of the Channel Island coral assemblages listed on the Register of the National Estate.

A more detailed evaluation of dredging operations and water quality can be found under section 4.5.2.

Recommendation 6

The proponent shall prepare an evaluation of the dredging, excavation and spoil disposal options. A dredging plan, addressing the environmental impacts, shall be submitted to the NT Government and Environment Australia for approval prior to commencement. The plan shall include proposed measures to ensure protection of the Channel Island coral assemblages. These measures shall include implementation of baseline studies, turbidity plume monitoring, a reactive coral monitoring program (if required), and contingency measures to be implemented if monitoring indicates adverse impacts.

Development of any monitoring and assessment programmes associated with the dredging plan shall be undertaken in consultation with the relevant NT Government agencies.

Acid leachate

The proponent is aware of the potential to create acid leachate from disturbance to mangrove muds, and has indicated that such disturbance will be minimised.

Adequacy of Description of Existing Environment

The draft EIS describes results from 6 samples of mud taken from 4 locations on the southern side of the plant site. These results indicate that while the samples contained levels of sulphur that could create acid conditions, there is sufficient calcareous material in the sediments to neutralise any acid produced. These results contrast greatly with experience from almost all development in the coastal zone of the Darwin area. Examples include the East Arm Port and the Bayview Haven residential estate. This issue should be resolved by collection and analysis of additional samples taken from appropriate areas (eg. construction dock, spill impoundment area and flare tower), and to appropriate depths.

Evaluation of Potential Impacts and Safeguards

It is acknowledged that the dredge spoil may not comprise sediments that would produce acid leachate, however there are other aspects of the project that may contribute to acid generation if not handled in the appropriate manner. For example the pipeline shore crossing, the landward end of the construction dock, the spill impoundment area and the flare tower will all require some excavation in the mangrove zone.

In the EIS, the proponent states that, if potential acid sulphate soils are likely to be disturbed during construction or disposal of spoil, an Acid Sulphate Soil Management Plan and Monitoring Program will be developed in consultation with NT DLPE Soil Conservation Officers. It is also stated that "where mangrove muds must be removed they will be stored in a basin adjacent to the construction dock and seaward of the mangroves." No construction details of this basin are given nor is there any specific commitment given to monitor leachate from retention basins or reclamation areas to determine if stored soil is producing acid.

Acid leachate generation is recognised as one of the major problems associated with coastal development in the Darwin region and as such has a high priority within the NT Government. It is therefore considered critical that an Acid Sulphate Soil Management Plan be prepared prior to commencement of construction.

Recommendation 7

An Acid Sulphate Soil Management Plan and Monitoring Program shall be prepared in consultation with relevant NT Government agencies. Sampling and analysis of potential acid sulphate soils should be conducted as part of preparing the plan. The plan shall include monitoring of leachate from any soil or spoil retention areas and reclamation areas, and contingency measures in the event leachate is found to be contaminated.

Waste water disposal

One issue addressed under Project modifications in the EIS, concerns the disposal methods of waste water. In the draft EIS, it was proposed that waste water would be discharged directly into Darwin Harbour from the loading jetty. In response to submissions, the proponent has advised that wastewater may now be disposed of through irrigation and landscaping and/or filtered discharge through mangroves to remove nutrients.

While these methods of disposal have the potential to reduce the impacts to marine habitats in Darwin Harbour and are encouraged, they must have the approval of the relevant NT Government agencies. All disposal methods must be undertaken in such a way as to avoid creating new breeding habitats for biting insects.

If direct discharges are required, modelling of the effluent mixing zone should be undertaken to the satisfaction of NT Government agencies to ensure that sufficient dilution will occur at the proposed discharge point to minimise impacts on nearby marine habitats.

Recommendation 8

The proponent shall consult with relevant NT Government agencies on measures needed, and applicable standards, for use of wastewater for land irrigation and/or as filtered discharge through mangroves, with a view to avoiding direct discharge to the waters of Darwin Harbour. If direct discharges are required, modelling of the effluent mixing zone shall be undertaken to the satisfaction of relevant NT Government agencies to ensure that sufficient dilution will occur at the proposed discharge point to minimise impacts on nearby marine habitats.

4.5 Construction Phase

4.5.1 Pipeline construction

Adequacy of Description of Existing Environment

This part of the assessment has been provided under section 4.4.2.

Evaluation of Potential Impacts and Safeguards

In general, direct environmental impacts associated with pipeline installation are displacement/destruction of benthos in the immediate vicinity of the pipeline and turbidity associated with trenching, rock dumping and construction of the shore crossing. The proponent suggests that once the pipeline is settled there will be recolonisation along its route.

It is acknowledged that the direct environmental impacts of the pipeline will be restricted to the immediate vicinity of its route. More or less temporary perturbations will result from burial and rock placement, but it is accepted that some recolonisation of the disturbed areas is likely. Disturbance to fauna normally found in the water column (fish, turtles, dugong, dolphins, whales) should only be temporary.

Potential impacts from pipeline work on the laybarge include those from possible spills of fuel and lubricating oils, waste water discharges and possible solid waste disposal. The EIS states that the only discharge from the barge will be treated sewage. While there is no mention in the draft EMP of measures to be undertaken should there be an oil or fuel spill, the EIS notes that an oil spill contingency plan will be required to be prepared by the contractor.

Other impacts from barge operations relate to the anchoring system, where the anchors will continually be raised and reset as the barge moves ahead. While it is accepted that such impacts are likely to be limited in extent and transitory, these should be further considered as part of the pipeline component of the EMP. It is also considered that the EMP should address measures to ensure that turbidity associated with rock dumping is minimised as far as possible.

As noted in section 4.4.2 impacts associated with maritime heritage occur mainly within Darwin Harbour. The Mauna Loa is located about 300 m from the proposed pipeline route; the Meigs, about 900 m; and the I-124 about 1.5 km of the proposed pipeline alignment. The proponent considers that there is a very low potential for physical disturbance of any of these sites by the pipeline laying operations. The SS Ellengowan at 1.5 km from Wickham Point is not considered to be at risk from the pipeline construction. The EIS states that the position of wrecks will be clearly marked by buoys to avoid any possibility of damage during the laying of the pipeline. This action may also be required for additional wrecks found during the detailed survey of the pipeline route within Darwin Harbour, depending on the results of consultations with the Heritage Conservation Branch of the DLPE.

Recommendation 9

The pipeline component of the Environmental Management Plan (EMP) shall address preparatory requirements for the pipeline (eg spanning support, rock dumping and stabilisation requirements) and measures to be implemented for the protection of the environment. The EMP shall also include measures to avoid and minimise impacts associated with laybarge operations including liquid and solid waste management and disposal, anchoring systems, and control of turbidity associated with rock dumping.

The installation and presence of the pipeline from the Bayu-Undan field to Darwin Harbour has the potential to impact on commercial fisheries through restrictions on access to the pipeline corridor and possible gear interactions.

The main commercial fishery areas potentially affected by the offshore pipeline are the Northern Prawn Fishery, Northern Territory Shark Fishery, Spanish Mackerel Fishery, Demersal Net Fishery, and Coastal Net/Line Fisheries. In addition, Japanese and Taiwanese fishing vessels are active beyond the Australian Fishing Zone (AFZ), with some Japanese vessels licensed to take tuna from within the AFZ.

The physical presence of the pipeline has most implications for the Northern Prawn Fishery. This fishery uses gear which make contact with the seabed. However, fishing effort is low in the pipeline area and the presence of the pipeline is not expected to present significant difficulties for the current fishery. The proponent considers that the concrete weight coating to be used for the pipeline would provide adequate protection in the event of trawling in the pipeline corridor.

The other relevant offshore fisheries employ gear, or fish in locations, where contact with the pipeline is not expected. Disruptions to these fisheries through the presence of the pipeline therefore appears unlikely.

The proponent states in the EIS that it is their intention to consult with relevant fishery associations in regard to the proposed pipeline construction schedule and associated fishing issues. An additional authority to be consulted is the Fisheries Division of the NT Department of Primary Industry and Fisheries (DPIF). The draft EIS states that the location of the pipeline will be marked on navigation charts, and that mariners will be notified through appropriate communication channels. In addition it is suggested that the proponent undertake to negotiate changes to construction timing, if necessary, to assist in minimising timing conflicts between pipeline laying and fishing.

In respect to Darwin Harbour, commercial net fishing is not permitted. However, limited gill netting and commercial line fishing are allowed. Recreational fishing in the Harbour mainly occurs in mangrove creeks, and in reef and channel areas.

Overall, it is considered that the pipeline is unlikely to significantly affect fisheries and diving opportunities in Darwin Harbour, or beyond, provided that sites of known shipwrecks are marked and avoided (see above).

Recommendation 10

The proponent shall advise all mariners, including commercial fishing operators and DPIF, of the detailed pipeline construction timetable and route, when available, and undertake to negotiate changes if necessary, to assist in minimising timing conflicts between pipeline laying and fishing.

4.5.2 Water quality

A number of issues associated with water quality have been addressed in section 4.4.3. That section dealt with issues related to further studies and development of plans that are required before commencement of construction. This section will address the impacts to water quality from all aspects of the construction phase of the project.

The major impacts to the water quality of Darwin Harbour, during construction, will be increased turbidity and sedimentation. This can be caused by material stirred up in the water column from the effects of the dredge, the release of sediment-laden decant water from the temporary reclamation area should it be required and surface runoff from disturbed terrain in the project area.

Dredging

Dredging is required in two major areas, the turning basin at the end of the loading jetty and the approach channels to the construction dock, and a smaller area for the pipeline shore crossing. Dredging works will result in temporary loss of benthic organisms in the path of the dredge. The other significant impacts will be the increase in turbidity in the vicinity of the dredge and the possible release of contaminants contained in the sediments.

Increased sediment load and turbidity will reduce light penetration to the seabed which may result in stress and mortality in corals, algae and other light dependent biota. In addition, increased sedimentation may lead to stress and mortality in benthic organisms from smothering or clogging of their filter feeding and respiratory organs. The proponent notes that corals react by producing more mucous to clean the polyps. This activity would be expected to place extra stress on corals that may be existing in an already sub-optimal environment. The proponent notes that the waters of Darwin Harbour have a high ambient turbidity. While this suggests that organisms in the harbour have adapted to high and variable turbidity levels, organisms such as corals may already be existing at the extreme of their tolerances, with the result that any additional prolonged exposure to turbidity could have a significant adverse impact.

Mobile marine biota (eg. fish, mammals, plankton) could be affected by the increased sediment load, however this is likely to be minor and transitory in nature.

Adequacy of Description of Existing Environment

Manly Hydraulics Laboratory (MHL) undertook modelling studies for turbid plumes from dredging and associated works. The model was used to compute the water velocity and surface elevation fields through a spring and a neap tidal cycle. The size of the fine and coarse sediments used for the model was based on particle size of sediments collected from the surface of the turning basin area. Results of the model were used to assess the dispersion characteristics of the turbid plumes generated by dredging operations at six locations. The dispersion characteristics were found to depend upon the magnitude of the tidal velocities near the six source locations.

MHL notes that the modelling indicates that plume concentrations produced by dredging will reduce to background levels within a few hundred metres of the source, and within 700 m for the construction dock works. Dredging in the shallower, low flow area of the proposed approach channel was shown to produce the largest plumes.

MHL notes that the model used in its study requires calibration, but that field data is not yet available. Consequently, MHL recommend that the turbid plume be monitored to enable calibration of the model.

Evaluation of Potential Impacts and Safeguards

The EIS notes that modelling predictions indicate minimal increase in turbidity, with only short-term stress on corals in the vicinity of the dredging. Hydrodynamic modelling for the draft EIS also predicts no adverse effect on the hydrodynamics of Darwin Harbour. It is also expected that the deepened seafloor will be recolonised by burrowing benthic biota.

As dredging for the ship turning basin is estimated to take 3 to 4 weeks, and for the construction dock about 2 to 3 weeks it is acknowledged that impacts from dredging are expected to be relatively short-term.

A two year study recently conducted in Darwin Harbour on the effects of dredging associated with development of the East Arm Port (Hanley and Caswell, 1995) concluded that, properly managed, dredging programs in the Harbour could be conducted with a minimum impact on corals.

One of the coral assemblages monitored since 1994 as part of the East Arm Port development is the Channel Island coral community which is listed on the Register of the National Estate. The EIS concluded that turbidity impacts on these corals from dredging of the turning basin was unlikely, in view of the modelling results and their distance from dredging areas (3 km). In addition, the EIS states that the predominance of water flow is to the south of Channel Island, along the main Middle Arm channel, rather than to the north of the Island, which would further reduce the chance of turbid plumes impinging on these coral communities.

The proposed pipeline crossing is closer to Channel Island and the sediment in this location may contain finer fractions. The EIS acknowledges that associated dredging or excavation works at this site may have the potential to impact on these coral communities. Dredging associated with the construction dock will not affect the Channel Island corals, as these works will occur in East Arm, well away from Channel Island. However, a coral community also exists to the north east of Wickham Point, which may potentially be affected by these works. This coral community has also been monitored as part of the East Arm Port development and was found to be unaffected by the dredging works for that project.

As part of the dredging plan, discussed in section 4.4.3, the proponent has committed to undertake discussions with appropriate NT authorities and the Australian Heritage Commission, aimed at ensuring protection of the Channel Island coral assemblages, particularly during works associated with the pipeline crossing. As noted above, a large amount of information has been collected on the biota of the Channel Island coral community. It is recommended that the proponent utilise this information in determining the kinds of studies and monitoring to be carried out. Further commitments are given to examine the actual turbid water plume during dredging to determine whether corals may be affected, and to institute a reactive monitoring program if required. The proponent also states that dredging effects on the coral community to the north east of Wickham Point will be assessed.

It is noted that the final dredging method and program is yet to be finalised (see section 4.4.3 and Recommendation 6). While the current information available suggests that dredging works can be managed to avoid impacts on the identified coral assemblages, this will need to be further analysed when the dredging program is finalised.

Clearing and excavation on Wickham Point also have the potential to contribute sediment inputs to Darwin Harbour. Various measures will be implemented by the proponent to reduce the potential for soil erosion and siltation of water. These will include minimising clearing, revegetation of temporarily cleared areas and drainage and erosion control works.

Construction of stormwater drains and other earthworks may result in the creation of breeding areas for biting insects. The proponent has undertaken to ensure that careful attention is given to the design and maintenance of earthworks and drainage systems to avoid this problem. The proponent has undertaken to consult with the Medical Entomology Branch of the Territory Health Services regarding a monitoring programme to determine the potential impact and health risks of biting insects to personnel at the site, and will also follow the recommended practices in Construction Practice Near Tidal Areas in the NT: Guidelines to Prevent Mosquito Breeding (Whelan, 1988).

4.5.3 Terrestrial Flora, Fauna and Habitat Management

Flora

Significant vegetation communities affected by the proposal include mangroves and dry rainforest. The EIS states that the area of vegetation to be cleared for construction of the LNG plant includes 11.9 ha of mangroves and 46 ha of dry rainforest under the revised plant footprint.

Adequacy of Description of Existing Environment

The draft EIS contains a detailed description of mangrove communities in the vicinity of the proposal, and notes that the most extensive areas of nearby prime mangrove habitat are found in the upper parts of Middle Arm and East Arm, and that high quality mangrove habitat is also present to the south-east of the plant in a small mangrove creek. None of these areas is likely to be directly affected by the plant.

As noted in Section 4.2, dry rainforest is an important vegetation type in the Darwin region. This habitat type is typically found in small pockets where local conditions support its continued existence. Its occurrence as small disjunct patches leaves pockets vulnerable to disturbance, and evidence presented in the EIS suggests that this vegetation type has been reduced in the Darwin region by about 60% in area in the 45 year period to 1993 due to urban development, fire, cyclone damage and weed excursion.

The Darwin region (Mandorah to Shoal Bay) has an estimated 1,595 ha of dry rainforest, which forms about 4.6% of the total 34,000 ha of similar habitat found throughout the Northern Territory. The 182 ha of dry rainforest found on Wickham Point (including the centre "island") represents 11% of the total in the Darwin region.

The flora survey conducted by the proponent found very few weed species in the dry rainforest habitat, with Lantana camara being the most abundant. This habitat is therefore considered relatively intact.

Evaluation of Potential Impacts and Safeguards

As noted in Section 4.2 the area of mangroves affected by the project will constitute approximately 0.02% of the total mangroves of Darwin Harbour and as such it is not considered that the project will compromise the overall productivity of the Darwin Harbour mangrove community.

Areas of mangroves that will be affected by the project will include the landward ends of the groyne and construction dock, the pipeline shore crossing, spill impoundment area, under the flare tower and a section between the LNG process area and the warehouse, laboratory and administration areas. Mangroves in the vicinity of construction works are proposed to be protected by a range of mitigating measures, including drainage and erosion controls.

Modelling by Manly Hydraulics Laboratory (MHL) shows potential for some sedimentation either side of the groyne. Mangrove zonation is very strong in this area and the increased sedimentation has the potential to alter the zonation patterns of the existing mangroves. The mangroves in this area should be included in the monitoring programme to ensure that the sedimentation does not adversely affect the adjacent mangroves.

It is considered that the proponent has taken appropriate steps to minimise clearing of mangroves. The above monitoring commitment, and measures provided in the draft EMP for protection of mangroves are supported.

In the EIS, the proponent acknowledges the importance of dry rainforest habitat and that loss of this habitat is a significant adverse impacts of the proposal. In this respect, the proposal would result in the loss of a major portion (43%) of the dry rainforest habitat on Wickham Point. Construction works, and ongoing operations, also pose a risk to remaining vegetation through weed incursion, fire, littering, and general disturbance from personnel.

The EIS states that the plant layout has been designed to minimise the amount of dry rainforest to be cleared. It is understood that there is limited scope for the proponent to further reduce the area of vegetation cleared for construction of the LNG plant, through redesign work aimed at minimising the plant's footprint.

The proponent has committed to obtain a quantitative baseline characterisation of the abundance of weeds, and feral animals, on selected portions of Wickham Point, which will not be disturbed by construction activities, prior to construction commencing. Monitoring will then be undertaken "at least annually" and any weed incursions removed on the advice of the NT Department of Primary Industry and Fisheries. Annual weed monitoring may be insufficient, especially given decreased resilience of the habitat to weed invasion following disturbance during construction and the potential for high growth rates during the wet season. In particular, clearing of dry rainforest will open up the canopy of adjacent dry rainforest and increase the likelihood of the spread of Lantana camara. Any weed monitoring should be undertaken in consultation with the relevant NT Government agencies.

The proponent has offered to work in cooperation with the NT Government in the management of the central island of dry rainforest at Wickham Point, which will be affected by the access road. While vegetation outside the project site, and the construction of the access road, are issues for the NT Government, the proponent's commitment to maintaining the integrity of the remaining dry rainforest habitat is acknowledged. It is considered that measures to avoid introduction of weeds and feral animals, littering and fire risks from vehicular access to the site would be important issues for the proponent's consideration.

Recommendation 11

The proponent shall include, as part of the EMP, specific measures to minimise loss and disturbance to remaining mangrove and dry rainforest habitat at Wickham Point. This shall include measures to avoid unnecessary clearing and disturbance during construction, measures to monitor and control weed and feral animal incursions, and measures to minimise fire risks.

Fauna

Adequacy of Description of Existing Environment

The terrestrial fauna of Wickham Point and the access route were documented through field surveys and reference to existing reports and databases. Several bird species recorded or likely to be found at Wickham Point are of conservation significance. These include the Little Tern (Sterna albifrons), the Melville Cicadabird (Coracina tenuirostris melvilliensis) and the Beach Stone-curlew (Esacus neglectus). The Little Tern is the only species currently listed under the Endangered Species Protection Act.

The EIS notes that the Little Tern is a wet season visitor to the Darwin region, and that it nests on undisturbed, unvegetated sites between the high tide mark and shore vegetation. Such habitat is generally not present at Wickham Point, and Darwin Harbour is not recognised as a breeding site. The proposal is therefore unlikely to have any implications for this species.

The EIS states that only a few pairs of the Beach Stone-curlew, which is considered to be vulnerable and highly susceptible to disturbance, are known to the Darwin area. Site surveys located a pair of Beach Stone-curlews nesting between the proposed pipeline shoreline crossing and the loading jetty groyne at Wickham Point. In response to several comments regarding the proponents expectation that the species will continue to use this habitat once the construction phase is complete, the proponent states that, following construction of the plant, areas of beach habitat will be left undisturbed. The proponent also notes that Beach Stone-curlews are frequently recorded on Varanus and Barrow Islands which both support well managed oil and gas developments.

The Melville Cicadabird was listed as endangered on Schedule 1 of the ESP Act in 1996 (ANCA, 1996), but was not listed in the latest (August 1997) revision. The EIS notes that in the Northern Territory, where more habitat is available, the species can be considered secure. Cicadabirds prefer pristine tall stands of Rhizophora mangroves, and in the Wickham Point area, were observed only along a small creek near the southern tip of the main island.

Twenty five species of waterbirds observed in Port Darwin wetlands are listed on international treaties. The Darwin region also has national and international importance for migratory bird conservation. The main habitats used by migratory shorebirds include mudflats, mangroves, estuaries, shorelines, reefs, and wetlands and non-wetland areas. Wickham Point includes a variety of such habitats and is routinely used by migratory birds.

Evaluation of Potential Impacts and Safeguards

The establishment of an LNG plant covering some 100 ha on a relatively constrained area, and which will extend its facilities across Wickham Point from shore to shore, will inevitably have significant impacts on fauna. These include direct destruction of habitat, interference to movement corridors, disturbance from noise, lights, and vehicles etc, risks from fire, and impacts from introduced weeds and animals. Wickham Point also includes several species which are recognised as vulnerable. The wetlands of Port Darwin are listed in A Directory of Important Wetlands in Australia (2nd Edition), in regard to their significance for migratory birds.

Destruction of habitat has been discussed in the previous section. The dry rainforest habitat is an important seasonal food resource for species that roost or forage in rainforest, including frugivorous vagrants. The EIS states that the loss of dry rainforest will result in a decrease in some species that are reliant on this habitat, but would support reduced populations of these species. Many of the species concerned are nomadic or migratory birds. While loss of habitat appears unlikely to directly threaten the status of any endangered or threatened species, all measures should be taken to reduce disturbance to residual vegetation (as noted above).

The proposal would result in the direct destruction of an estimated 11.9 ha of mangroves and disturbance to about 600 m of shoreline, mainly in the vicinity of the construction dock, however, this is unlikely to significantly affect the use of Darwin Harbour, or Wickham Point, by migratory birds.

The EIS states that the free movement around Wickham Point of species such as Agile Wallabies (Macropus agilus) and Northern Brown Bandicoots (Isoodon macrourus) would be limited where movement corridors are cleared or obstructed. Construction of the LNG plant, perimeter road and access road could provide a physical barrier to fauna movement between the area of the plant site and dry rainforest further inland. Fauna underpasses will be installed beneath the loading jetty and obstruction of the mangrove hinterland fringe on the south side of Wickham Point will be minimised to enable fauna movement. The proponent notes that most fauna is nocturnal and would be moving when traffic is minimal.

Several Scrubfowl mounds will be destroyed in the construction of the plant. Those mounds that are outside the site will be left undisturbed and, as with all areas outside the plant site, access will be restricted.

Very few feral animal species were noted in the initial qualitative survey. As noted above, the proponent also proposes to undertake quantitative baseline characterisation of the abundance of feral animals on selected portions of Wickham Point that will not be disturbed by construction activities. The proponent further notes that quantitative surveys of feral animals will be conducted prior to and on completion of the construction phase, and that "regular and frequent" sightings of feral pests will be reported to the Parks and Wildlife Commission of the NT.

The requirement for monitoring and control of feral animals is given as a commitment in the draft EMP and is strongly supported by the NT Government.

4.5.4 Heritage, Cultural and Social issues

The main heritage and cultural issues associated with site construction are considered to be the significance of Wickham Point and surrounding areas to Aboriginal people and terrestrial heritage sites. Maritime heritage issues have been addressed in Sections 4.4.2 and 4.5.1.

Aboriginal significance

The proponent consulted with the Larakia people during the preparation of the draft EIS and concluded that Wickham Point is perceived by the Larakia and other Aboriginal people around Darwin Harbour as being important, for the following reasons:

• it has played a part in particular periods of Aboriginal history (including since European settlement);
• Aboriginal people may have been buried on Wickham Point;and
• adjacent marine areas may be used as a source of food, and there is a high diversity and abundance of ethno-botanic floral species on Wickham Point.

Following a commitment in the draft EIS to consult further with the Larakia and other Aboriginal people prior to finalising the EIS, a supplementary anthropological study was included in the Supplement. This study included several site visits and meetings with relevant Aboriginal groups and families during October 1997. The study notes the spiritual significance of Wickham Point to the Larakia people and concludes that the Larakia seek acknowledgment of their historical and cultural connection with the land and recognition of the impact that the development will have on them.

As part of the draft EMP the proponent has undertaken to consult with the Larakia people on a regular basis through a liaison committee. This committee is intended to function as a principal point of contact between indigenous interests and the proponent in regard to the plant site throughout construction and operation of the facility. The proponent has undertaken to suspend construction work if Aboriginal artefacts or apparent burial sites are uncovered and report these to the relevant authorities. The proponent will use the liaison committee to fulfill its statutory obligations and its undertakings given in the EMP.

The NT Government supports the approach being taken by the proponent, in particular the establishment of the proposed liaison committee.

Terrestrial Heritage Sites

Adequacy of Description of Existing Environment

A survey of Wickham Point located nine archaeological sites, most of which are within or immediately adjacent to the proposed LNG plant site. Six of these sites are prehistoric shell middens, two are historic sites dating from World War II and one is the remains of the Mud Island leprosarium near the tip of Wickham Point. The EIS notes that three archaeological sites on Wickham Point will be lost by the construction of the LNG plant, while a further three sites will be disturbed.

The historic Mud Island leprosarium is registered as a Heritage Site under the NT Heritage Conservation Act 1991. The proponent states in the EIS that, because of its distance from the construction site, this site will not be impacted by either construction or operation of the LNG plant, and therefore no action is required to preserve it apart from ensuring it is signposted as "off limits". No archaeological sites were identified along the proposed access road.

Evaluation of Potential Impacts and Safeguards

An archaeological sites register for the entire project will be established in consultation with the Heritage Conservation Branch of DLPE. It is proposed that this register will be used to educate all construction and operations personnel of the location and significance of signposted "off limits" areas.

While Aboriginal burials are likely to have occurred near the leprosarium site, and possibly in shell middens in the area, the draft EIS reports that no Aboriginal burial grounds are known from Wickham Point. If any new archaeological artefacts or historic sites are discovered, work at a particular site will cease and the DLPE Heritage Conservation Branch will be notified as soon as practical.

While the World War II sites are considered to be of low archaeological significance, the prehistoric Aboriginal middens are considered highly significant based on the criteria of representativeness and research potential. The proponent notes that every effort will be made to protect 4 of these sites, if possible, by erecting fencing around them and prohibiting entry and heavy machinery access to within 20 m. For sites within the plant perimeter, the proponent will consult with Heritage Conservation Branch of the DLPE regarding obtaining a permit to destroy the middens under Section 29 of the NT Heritage Conservation Act 1991.

It is considered that issues associated with terrestrial archaeological and heritage sites have been adequately addressed in the EIS. The proponent will be required to consult with the Heritage Conservation Branch of the DLPE regarding requirements of NT legislation and procedures for management of archaeological sites. To protect heritage sites, the proponent has advised that it will ensure that all authorisations have been received from the NT DLPE and the Aboriginal Areas Protection Authority (AAPA) before commencement of construction activities.

4.5.5 Waste Management

Waste management during the construction phase of the project will be included as a component of the Construction Management Plan (CMP). The proponent has committed to dispose of wastes in accordance with NT Government requirements and should therefore liaise with appropriate NT Government agencies during the development of the CMP.

4.6 Operational Phase

As noted above, the proponent intends to prepare a detailed EMP incorporating an Operations Management Plan (OMP). The main environmental issues associated with operation of the LNG plant are atmospheric and greenhouse gas emissions, water quality, waste management and hazard and risk management (addressed separately in Section 4.7).

4.6.1 Plant Site Management

The management plans and monitoring introduced in the construction phase to maintain the ecological value of the remaining vegetation are expected to continue into the operational phase. Actions will include on-going control of weeds, feral animals and fire as well as maintenance of fauna underpasses and "off-limits" restrictions.

As part of the environmental management program, the proponent has undertaken to monitor mangroves in the vicinity of the plant to confirm that mangrove productivity adjacent to the plant perimeter will not be affected by plant operations, and to minimise disturbance. Monitoring the condition of the mangroves will be based on visual inspection and qualitative assessment. Remedial actions should also be detailed in the OMP in the event that adjacent vegetation appears to be affected as a result of the operation of the plant. This may require such actions as drainage modifications or an assessment of the effects of air emissions on the vegetation. It is suggested that the auditing procedures outlined in the preliminary EMP include vegetation management.

Monitoring and control of biting insects will also continue during the operational phase in consultation with the Medical Entomology Branch of the Territory Health Service. It is suggested that mosquito breeding sites be included specifically in the Site Environmental Audit.

Recommendation 12

The proponent shall ensure that on-going management of remaining vegetation and fauna habitats will be undertaken, including monitoring of weeds and feral animals and prevention of fires. The EMP shall include measures to mitigate any impacts in the event that adjacent vegetation appears to be affected as a result of the operation of the plant. Vegetation management and mosquito breeding sites shall be included in the Site Environmental Audit.

4.6.2 Air emissions

The operation of the LNG plant will produce a number of atmospheric pollutants. These include carbon dioxide (CO2), carbon monoxide (CO), oxides of nitrogen (NOX), sulphur dioxide (SO2), particulate matter smaller than 10µm (PM10), and volatile organic compounds (VOC). Atmospheric emissions will be produced by combustion and from fugitive emissions (leaks). Carbon dioxide is the main greenhouse gas emission.

Adequacy of Description of Existing Environment

The proponent undertook air dispersion modelling to determine ambient concentrations of CO, NOX, PM10 and SO2. The modelling indicated that maximum ground level concentrations for all pollutants are expected to be below NT and expected national guidelines. On this basis, the proponent stated that emissions from the LNG plant are not expected to cause adverse short or long term effects on the local environment.

The proponent noted that the concentrations of nitrogen oxides produced by the compressor turbines came closest to the ambient criteria. In this respect, alternative turbine technology in the form of dry-low-NOX (DLN) turbines is available, and which produce lower levels of NOX. However, the proponent states that DLN technology is not favoured for this plant because of their reduced efficiency, higher costs and technical risks. It is acknowledged that, while DLN technology may reduce NOX emissions, turbine efficiency may also be reduced with uncertain overall greenhouse gas implications.

The proponent notes that the NOX concentration in the turbine emissions will be in excess of the National Health and Medical Research Council (NHMRC) value of 25 ppm. However, the proponent also notes that dispersion modelling indicates that ground level concentrations of NO2 will remain well below established ambient criteria for NO2.

Combustion of LNG in the compressors and heat generated by the air fin coolers will produce a considerable heat plume. Air dispersion modelling indicates that plumes will diluted by a factor of 1000 within tens of metres from the plant and by more than 10,000 times within a few hundred metres from the plant.

Evaluation of Potential Impacts and Safeguards

The proponent undertook further preliminary air dispersion modelling in response to submissions commenting on the effect of the proposed plant expansion. This indicated that emissions would be likely to be within accepted standards, apart from NO2 in the immediate vicinity of the site. As noted in Section 4.4.1, any proposal for expansion would be subject to further assessment under the NT Environmental Assessment Act, including more detailed assessment of emissions.

The National Environment Protection Council (NEPC) is currently in the process of developing national ambient air quality standards as part of a national environment protection measure (NEPM) for ambient air quality. Once adopted by Council, the standards within the measure will be mandatory in all participating jurisdictions, including the NT. Compliance with this standard will be administered by NT DLPE.

The proponent has undertaken to prepare an inventory of atmospheric emissions. In addition, a commitment to confirm the emissions estimates by measuring the major emission sources will be conducted, focussing on nitrogen dioxide, the major expected pollutant.

Recommendation 13

The proponent shall consult with DLPE regarding preparation of the atmospheric emissions inventory and any related monitoring. Both the inventory and any monitoring shall be implemented to the satisfaction of the DLPE.

The proponent shall consult with DLPE regarding preparation of the atmospheric emissions inventory and any related monitoring. Both the inventory and any monitoring shall be implemented to the satisfaction of the DLPE. The proponent shall verify, by monitoring for NO2, that there will be no exceedances, arising from atmospheric emissions, of the standards contained in the proposed Ambient Air Quality NEPM. Monitoring procedures and data reporting must meet the NEPM requirements and Australian Standards. Monitoring points shall be determined in consultation with DLPE.

Greenhouse gas emissions

The LNG plant will be a major producer of greenhouse emissions, principally in the form of CO2. The sources of CO2 are the incoming LNG stream, the burning of LNG in the turbine drivers, and from flaring.

The proposal will unavoidably contribute to Australia's greenhouse emissions at a time when the Commonwealth is committed to controlling such emissions. All measures to minimise CO2 emissions should be investigated as part of the ongoing operational EMP for the proposal.

In the draft EIS, the proponent notes that the main product of the plant will be LNG, which is recognised as a relatively clean burning product, compared to other fossil fuels. The implication is that LNG production and consumption as a fuel will result in a net global reduction of greenhouse gases if LNG is substituted for other fossil fuels in energy production. While this argument is acknowledged, the development of the Bayu-Undan field will inevitably result in additional CO2 emissions.

The majority of the CO2 associated with the plant is produced by the turbines as a result of fuel gas combustion. The proponent notes that efficient turbine technology will be used and that the turbines will be fuelled by LNG, which produces lower levels of greenhouse emissions than other fossil fuels.

Evaluation of Potential Impacts and Safeguards

As part of its environmental commitments, the proponent will undertake a greenhouse gas audit, and the Greenhouse Challenge Office will be contacted with a view joining this program.

It is considered that, in addition, the proponent should include a specific module in the operational EMP specifically dealing with ongoing measures to reduce greenhouse emissions. This should include a mechanism for continual review of new technologies and opportunities to reduce emissions, and benchmarking against other LNG facilities with a view to achieving international best practice in terms of CO2 emissions per unit of production. Offsetting measures for greenhouse gas production, such as deep water injection should also be addressed.

Recommendation 14

The EMP shall include a section specifically addressing commitments and strategies aimed at reducing greenhouse gas emissions. This shall include, for example, provisions for regular greenhouse gas audits, a process for continuous review of new technologies to identify opportunities to reduce emissions, and benchmarking against other LNG facilities with a view to achieving international best practice in terms of CO2 emissions per unit of production. Opportunities for offsetting greenhouse gas emissions, including support for relevant research shall also be addressed.

The greenhouse gas strategy shall be provided to Environment Australia and the DLPE for comment. Participation in the Greenhouse Challenge Program should also be explored by the proponent.

4.6.3 Water quality

The main potential impacts to water quality from operation of the plant are discharge of waste water, stormwater runoff, introductions of marine pests in ballast water and metal accumulation in the sediments at the loading jetty. The preliminary EMP outlines either management actions or monitoring programmes for the above potential impacts.

Waste water

As noted in Section 4.4.3, the proponent is investigating alternative methods of disposal for waste water. Options include using treated waste water for irrigation purposes and filtering waste water through mangroves. Investigations should be undertaken in consultation with the relevant NT Government agencies. A discharge licence will be required for any discharge of waste water from the site, whether it be directly from the jetty or filtered through mangroves, and approval must be sought from Environmental Health Branch of Territory Health Services for the use of treated sewage as irrigation water. If filtration through the mangroves is chosen as the preferred option, care should be taken to ensure that no new breeding grounds for biting insects are created.

The proponent has made a commitment to establish water effluent monitoring programmes in order to confirm compliance with discharge permit criteria. The monitoring will determine volume, concentration of contaminants and dispersal of effluent for both sewage and process water. Dispersal will be determined by in-field effluent dispersion surveys during both neap and spring tide conditions. Mitigating measures must be in place in the event that discharge permit limits are exceeded.

The NT Government should be consulted regarding the final choice for disposal of treated waste water as stated in Recommendation 8.

Stormwater

Stormwater runoff from industrial sites can contribute to pollution of water bodies through contamination, erosion and litter.

It is acknowledged that the LNG plant is a relatively clean industry and that most stormwater runoff will be uncontaminated. In the EIS it is stated that potentially contaminated stormwater from the process area will be collected and treated to remove oil before release. Clean stormwater will be directed to collection systems that will be designed and constructed to control discharges and minimise soil erosion.

The proponent understands that poorly planned drainage systems can result in changes to species composition, build up of undesirable vegetation and the creation of breeding habitats for biting insects. It is suggested that the drainage system is inspected periodically, as part of the Site Environmental Audit, for signs of impacts to the environment. Remedial measures, such as modification to the drainage system or installation of trash racks, should be detailed in the EMP.

Metal and contaminant accumulation

One of the impacts associated with ports or industrial facilities that use sea transport, is accumulation of heavy metals and tributyltin (TBT) in sediments. Heavy metals may also bio-accumulate in molluscs. Very low concentrations of TBT are known to produce physiological changes in some marine invertebrates, leading to local extinctions in some instances (WA DEP, 1996).

In the EIS, the proponent has undertaken to conduct a baseline study to quantify concentration of contaminants, including tributyltin (TBT), metals such as uranium, arsenic and radium, and hydrocarbons, in sediments and selected biota in the vicinity of the ship loading facility. Subsequent monitoring will be conducted in consultation with the appropriate NT Government agencies. The proponent has also undertaken to use various means to reduce the potential for accumulation of metals and TBT in sediments including prohibiting the use of hull cleaning machines on vessels moored at the jetty, and ensuring that the corrosion protection system on the jetty is maintained at optimum levels. The proponent should also ensure that any new technologies associated with antifouling methods are investigated with a view to reducing the impact of existing system. Results of these investigations should be provided to the DLPE as part of reporting requirements.

Introduced marine organisms

In the last few years there has been an increased awareness of the problems associated with marine organisms introduced to Australian waters through ballast water. Because several species have become significant pests in some southern ports of Australia, a national survey and monitoring programme has been established by the Australian Quarantine Inspection Service (AQIS). The Darwin Port Authority will be implementing a monitoring programme as part of this initiative.

While it is acknowledged that tropical regions may be less susceptible to impacts from introduced marine organisms, this will only be verified when results of the survey and monitoring programme are known.

The proponent has undertaken to ensure that all vessels will be required to comply with the International Maritime Organisation and AQIS guidelines for ballast water discharge at sea before entering ports of call. The proponent has also undertaken to contribute to the Darwin Port Authority's proposed monitoring programme, and if necessary undertake a risk assessment of its shipping operations.

4.6.4 Waste Management

Waste management during the operational phase of the project will be included as a component of the Operations Management Plan (OMP). The proponent has undertaken to dispose of wastes in accordance with NT Government requirements and should therefore liaise with appropriate NT Government agencies during the development of the OMP.

4.7 Hazard and Risk Assessment

Inherent hazards and risks are associated with the operation of a LNG processing facility and its location in an area subject to cyclone and storm surge. This project is one of the first of its kind in the Northern Territory, and as such, planning and zoning controls and relevant occupational health and safety legislation are used to control such industries rather than formal risk acceptability criteria.

4.7.1 Plant site

The proposed LNG processing plant will be classified as a major hazard facility under the National Standard for Control of Major Hazard Facilities and the National Code of Practice for the Control of Major Hazard Facilities, Standards developed by the National Occupational Health and Safety Commission (NOHSC). These standards have the objective of minimising hazards and risks and are implemented and enforced by the NT Work Health Authority. The major piece of applicable NT legislation will be the Dangerous Goods Act 1980 and the Australian Standards called up by that Act.

A Preliminary Hazard and Risk Assessment was prepared for the proponent by the Bechtel Corporation, a United States based company (contained at Appendix P of the draft EIS). This states that the facility would comply with all relevant Northern Territory, Commonwealth and international codes, standards, guidelines and legislation. Specific standards to be used in construction and operation are specified, including overseas standards. In response to a request that specific Australian Standards be used, the EIS stated the proponent's commitment to comply with relevant Australian Standards.

The preliminary Hazard and Risk Assessment (HRA) provided a largely qualitative assessment of hazards and outlined a number of further studies to be prepared at the detailed design or operational stages. The assessment concluded that hazards and risks from the facility and associated operations would be acceptable, and that appropriate best practice design, engineering and operational measures could be implemented to ensure that hazards and risks were minimal.

The DLPE sought a review of the preliminary HRA from the Western Australian Department of Environmental Protection (WA DEP), in view of their experience in assessing similar facilities in that State. This review drew attention to a number of potential hazards from the plant and recommended that a land use plan be developed for the Wickham Point area, and that further risk assessment, including a full Quantitative Risk Assessment, be conducted at the detailed design stage. A major issue concerned the amount of available land, as comparable LNG facilities in WA require more land than is currently available on Wickham Point. The review also recommended that several assessments be conducted as the plant design progresses. These are:

• a full Quantitative Risk Assessment (QRA) looking at onsite, offsite and ecological risks;
• from the risks identified in the QRA, a Safety Report and Management System in accordance with the NOHSC standards; and
• an Environmental Management System (to AS 14000).

The review also drew attention to the lack of assessment of ecological risks in the preliminary HRA. It was suggested that several "probable release" scenarios should be used to indicate the extent of environmental damage in each case.

Evaluation of Potential Impacts and Safeguards

The Supplement provided additional information following the review by the WA DEP and demonstrated that the available land area is of sufficient size to provide for the plant expansion if required due to the Phillips process having a smaller footprint than other LNG processing facilities. The issue of a land use plan for the Wickham Point area is a matter for NT Government concern and has been addressed in Section 4.2.

Several factors point to the suitability of the proposed site for the project:

• the relatively remote location of the site, and "natural" buffers provided by the waters of East Arm and Middle Arm;
• the site is distant from existing or proposed residential areas;
• the technology to be used for the plant is well understood; and
• the "best practice" measures to be used to reduce risks associated with the plant and its operations.

In these circumstances, and on the basis of the preliminary hazard and risk assessment, it is considered that the proposed site is likely to be suitable from a hazard and risk viewpoint and that the proposal can be managed to ensure that hazards and risks are acceptably low. These circumstances would need to be confirmed by further analysis in the event of plant expansion.

It is acknowledged that most hazards are likely to relate to events within the immediate vicinity of the plant or jetty loading facility and this was confirmed by further analysis undertaken in the Supplement. However, further studies and plans are required to confirm the results of the preliminary study, and to provide the basis for ongoing hazard and risk management. These are detailed in the EIS, and include:

• a Hazard and Operability Study (HAZOP) to be undertaken at the detailed design stage;
• a Quantitative Risk Assessment following completion of the HAZOP;
• detailed Safety Report, consistent with the NOHSC standards, prior to operation of the plant (including site operating procedures, training, pre-startup safety review and audit and reporting provisions); and
• detailed emergency response plans/procedures.

All relevant components of the Hazard and Risk Assessment must cover ecological risk as well as risk to human life.

The EIS states that the detailed Emergency Management Plans and procedures will be developed, in conjunction with civil and maritime authorities, during the detailed design stage. Separate emergency response plans are proposed for the LNG plant, product loading facility, LNG carrier operations, oil spills, and pipeline rupture. The EIS stated that these plans would be developed consistent with the NOHSC standards.

The review by the WA DEP also noted that the plant would need to be self sufficient from an emergency response viewpoint, given its distance from Darwin. In this respect, measures such as automated firewater monitors, remote coverage and gas detectors are to be included in the plant.

Recommendation 15

The proponent shall ensure that relevant components of the Hazard and Risk Assessment cover ecological risk as well as risk to human life. All components of the Hazard and Risk Assessment, including Emergency Response Plans, shall be provided to the NT Government for review before finalisation.

4.7.2 Flares and aircraft safety

The draft EIS noted that the proposed LNG Plant was within the Darwin Airport Primary Control Zone and is about 5.5 nautical miles on the direct approach path for the north-south runway at the airport. The draft EIS stated that this runway was primarily used by smaller training and passenger aircraft, with 19,000 aircraft using the runway per year. Darwin Airport is used for domestic and international flights, as well as for military purposes, on a 24 hour a day basis.

While the plant would not affect operations of the main runway, airport authorities have expressed concern that the main plant flare may adversely impact on approaching aircraft to the north-south runway. Under Visual Instrument Flight Rules operations, the Southern approach currently overflies the plant location at a minimum height of 500 feet. The Wickham Point site also falls within the proximity of RAAF Base Darwin, and Department of Defence approval is required for structures higher than 90 metres above ground level. The EIS stated that the plant would have a total of three flares, of which the wet and dry flares would be 40 m high each.

The draft EIS considered that a 500 feet danger area above the highest point of the plant would be sufficient when there was no gas flaring. However, it was not clear whether this standard would be applicable for a flare stack, particularly if "unexpected" emergency flaring was likely. The WA DEP, in their review of the preliminary HRA, stated that it would be desirable to avoid aircraft overfly of the plant because of the risks of accident.

The preliminary HRA did not contain an analysis of potential hazards from flare tower emissions on normal aircraft operations, or possible mitigation measures required. The EIS stated that the wet and dry gas flares were expected to operate for about 6 to 7 hours per year.

It is understood that the issue of flaring and possible safety interactions with southern approaches to the north-south runway is subject to ongoing negotiations between the proponent and relevant authorities. The proponent is confident that these negotiations will resolve this issue or, alternatively, other options can be used to avoid impacts from flaring. If continuing negotiations indicate the potential for safety interactions, further analysis of hazards and risks to aircraft from flaring should be required prior to a final decision on the type or nature of flaring to be used.

Recommendation 16

Negotiations between the proponent, the RAAF, Darwin Airport authorities, Air Services Australia and the Civil Aviation Authority to resolve outstanding concerns in regard to safety interactions between flaring and approaches to the north-south runway at the airport are noted. If negotiations indicate the potential for safety interactions, further analysis of hazards and risks to aircraft from flaring shall be required prior to a final decision on the type or nature of flaring to be used.

4.7.3 Pipeline Rupture

The main risk to the biophysical environment from pipeline operations is that of pipeline rupture or leakage.

An outline of a Pipeline Rupture Contingency Plan to address emergency handling procedures in the event of a rupture, is included in the EIS. The outline includes precautions to be taken to avoid leak and rupture incidents, including design measures to minimise risks from extreme storm and cyclonic activities, cathodic anti-corrosion protection, routing to avoid risk of external disturbance from shipping and fishing activity, protection of the pipeline by combinations of concrete coating, rock dumping or trenching in areas potentially sensitive to external disturbance, and periodic internal and external inspections.

The EIS also indicates that several systems would be used to ensure pipeline integrity and Appendix D of the draft EIS refers to measures proposed to protect the pipeline from corrosion and arrangements for monitoring.

Evaluation of Potential Impacts and Safeguards

In the event of rupture, a considerable volume of gas will be released from a pipeline 500 km long and 660 mm in diameter. The impacts of such an event could include freezing of sea water in the vicinity of the rupture, impacts on animals caught in the bubble upwelling zone and impacts on surface animals and birds (natural gas is lighter than air) in the immediate vicinity.

In the EIS, the proponent noted that the raw gas to be transported will contain less than 1% condensate and this would be released into the marine environment in the event of a major rupture. The buoyancy of the gas would preclude any impacts on the seabed from condensate, except in the immediate vicinity of the leak. Turbulent mixing within the water column, and rapid evaporation (6-12 hours) at the sea surface, would minimise impacts on local fauna. According to the proponent, mangrove and coral habitats are greater than 5 km distant at the entrance to Darwin Harbour and greater than 50 km distant from the pipeline route outside of the Harbour, and would be unlikely to be adversely affected by condensate from a major rupture.

It is acknowledged that the major product to be carried by the pipeline is gas, and that the potential impacts of a catastrophic rupture are therefore less than from, for example, an oil pipeline rupture. Nevertheless, some condensate will be carried and all measures should be taken to minimise the risks and consequences of a rupture.

The Pipeline Rupture Contingency Plan should address the entire pipeline length including within Darwin Harbour, and include contingency measures, noting that emergency responses are likely to be different, for example, depending on the proximity of the pipeline to shore based emergency response teams. In addition, the Plan should be expanded to include measures to minimise external and other risks to the pipeline, such as from commercial fishing activities, Defence operations and future marine construction works, and monitoring and leak detection strategies and systems.

Recommendation 17

The proponent shall provide a Pipeline Rupture Management and Contingency Plan for the entire length of pipeline, prior to its commissioning. This Plan should outline detailed measures to minimise risks of leakage and rupture, including external risks to the pipeline, and strategies and systems to monitor, detect and repair leaks (including measures to detect and repair potential areas of leakage). Detailed contingency measures to ensure quick reaction to major incidents, including measures to minimise environmental harm and environmental remediation if required, shall also be included. The plan shall be prepared to the satisfaction of Environment Australia, the Commonwealth Department of Primary Industries and Energy and the Northern Territory and Western Australian Governments.

4.7.4 LNG carriers

Adequacy of Description of Existing Environment

The EIS briefly discussed hazards and risks from LNG carrier operations. Manoeuvring operations near the loading wharf would occur away from the main port shipping channel, and significant safety interactions are not expected. It is also stated in the EIS that LNG carriers are designed, built and operated in accordance with well established procedures to minimise hazards and risks and ensure safety.

Evaluation of Potential Impacts and Safeguards

Marine traffic controls will be imposed by the Darwin Port Authority to minimise risks of collision and grounding, and to ensure that navigation and traffic interactions are acceptable from a safety and traffic management viewpoint. A 500 m "moving exclusion zone" around each LNG ship as it proceeds through the Port to its berth is proposed, to minimise safety risks. The proponent has also committed to discussions with the Royal Australian Navy to eliminate traffic conflicts and minimise risks regarding possible interactions with Naval traffic.

The EIS also stated that a Port Emergency Plan would be developed with the Darwin Port Authority and the Royal Australian Navy to address responses to non-routine or potentially hazardous situations.

Cyclone and other extreme weather events are also discussed in the EIS. It is proposed that limits will be set, in consultation with the Darwin Port Authority, to provide safety in these conditions. Limits, particularly wind and wave conditions, should also be specified for safe/unsafe loading conditions. The proponent advised that those instances where a ship should be disconnected and moved from the berth (eg extreme weather conditions) would be defined. In these circumstances, both the berth and ship operators would be able to initiate emergency shut-down of LNG transfer. These procedures would be detailed as part of the LNG carrier operations emergency management plan.

According to the EIS the emergency management plan would also address emergency situations involving carriers at sea, particularly in Beagle Gulf or approaches to Darwin Harbour. This plan will take account of existing contingency plans for oil tankers in the area, but with modifications to allow for the specialised nature of LNG carriers and their cargo.

Recommendation 18

An emergency management plan addressing LNG carrier operations at sea, in Darwin Harbour and at berth shall be developed in consultation with relevant authorities such as the Darwin Port Authority and Australian Maritime Safety Authority. The plan shall include matters such as measures to ensure compliance with national and international safety regimes, reporting procedures and organisational responsibilities in the event of incidents, control of incident responses, contingency measures to minimise risks to human safety and the environment, minimum resources to be held on ship and at berth to deal with credible contingencies, and interactions with shore based or other emergency response teams.

4.7.5 Oil Spills

One of the major potential threats to the environment from the operation of the facility is from oils spills. Operations at the proposed berth may pose a risk of oil spills, particularly of fuel oils. While spills are most likely to be of small volume, resulting from ad hoc accidents and spillages, the potential exists of degradation of the near shore environment over time from accumulated spills. A larger spill, for example from rupture of a fuel oil tank, may pose an immediate risk to mangrove and other intertidal ecosystems.

Evaluation of Potential Impacts and Safeguards

The EIS did not contain an assessment of likely volumes in the event of an oil spill, but noted that fuel oil could be released into the harbour or coastal waters from LNG vessels. The most likely cause for a major release would be through collision with the berthing jetty or other vessel, or grounding. The potential also exists for spills during handling and loading of condensate, to be produced as a by-product of the LNG process.

The proponent notes that the Darwin Port Authority has legal jurisdiction for dealing with oil spills in Darwin Harbour and that it had developed an Oil Spill Contingency Plan. While this plan would assume overall responsibility for major spills in the Harbour, the proponent advise that they will prepare a "supplementary plan", specific to the LNG plant, in consultation with the Darwin Port Authority. Elements of the plan are stated to include organisational responsibilities, actions, reporting requirements and resources to ensure effective and timely management of an oil spill in the Darwin Harbour area.

The NT Government notes and supports the proponents intention to develop an oil spill contingency plan for the port facility, and considers that this plan is essential to ensure that risks of spills are minimised and that suitable contingency measures are in place in the event of a spill.

Recommendation 19

An oil spill contingency plan for the port facility shall be prepared by the proponent, within the overall context of the Darwin Port Authority Oil Spill Contingency Plan. The site specific plan should include an assessment of potential risks of spills and credible volumes, potential oil spill trajectories, maps of priority areas for protection including aquaculture facilities, deployment of equipment to protect priority areas, integration with the Darwin Port Authority Plan, inventory of equipment to deal with control and clean-up (including materials held at the wharf for immediate clean-up of minor spills), strategies , actions and responsibilities for any clean-up, and a training and exercise regime (including with Northern Territory authorities).

4.8 Decommissioning

Decommissioning will occur at the end of the LNG Plant life. The expected life of the plant is 20-25 years with the possibility of extension if future gas reserves are available.

It is stated in the EIS that rehabilitation of the plant site will occur in consultation with the appropriate NT Government agency and in accordance with standard practice at the time. At present, it is intended that the pipeline will be purged of all hydrocarbons, flooded with seawater and left on the sea bed. It is understood that the pipeline will deteriorate slowly and any oxidation products are not expected to adversely affect marine life during this deterioration.

This commitment is made with the knowledge and technology that is available now. It is likely that new technology or increased awareness of environmental issues may require a modification of the expected plant and pipeline decommissioning. Therefore decommissioning should take place according to the best environmental standards available at the time.

Recommendation 20

The proponent shall ensure that decommissioning is carried out according to the best environmental standards available at the time.

4.9 Monitoring

A component of the EMP outlined in the EIS is a detailed Environmental Monitoring Programme. Various monitoring programmes are expected to be undertaken during both phases (construction and operation) of the LNG plant. Most have been addressed in this Assessment Report. The development, implementation and review of all monitoring programmes should be undertaken in consultation with the DLPE. To this end, the DLPE should also be provided with any results from baseline studies and monitoring programmes conducted during the design, construction and operational phases of the project.

Recommendation 21

The proponent shall consult with the DLPE in the preparation, implementation and review of all monitoring programmes. The DLPE shall also be consulted regarding any mechanisms and actions developed as a response to monitoring results.

4.10 Access Road

The access road will pass through sensitive areas of dry rainforest and mangroves. The proponent has undertaken to cooperate with any NT Government actions to protect and manage the centre "island" of dry rainforest that will be traversed by the access road.

As part of this commitment the proponent has provided an undertaking to minimise the likelihood of introduction of weeds and feral animals to the area as a result of its own operations. Suitable measures should be included in the EMP. These may include, for example, measures to avoid introducing weeds along the access route, measures to minimise littering, fire risks and general disturbance from vehicular movements associated with the proposal, and provision for onsite fire fighting capacity to respond to fires, or other emergencies, along the access route.

Because the responsibility for the access road was transferred to the NT Government after preparation of the draft EIS, the proponent did not address the issues identified in several submissions relating to its construction. The issues include impacts to the dry rainforest, mangroves and hydrology as well as problems associated with the disturbance to mangrove mud and the possibility of acid leachate generation. These issues are therefore outstanding in this assessment and require further investigation.

The EPD will be a member of a Design Control Group established to oversee the design and construction of the access road and ensure that the above impacts identified in the environmental impact assessment process will be prevented or minimised.