3.0 Regional Setting
The project is centred in the Darwin region of the Northern Territory. The pipeline extends from the Timor Sea, approximately 500 km north west of Darwin, across the continental shelf of northern Australia to Darwin Harbour.
Sections of the following description are based on information provided in the draft EIS.
3.1 Offshore region
The Bayu-Undan field lies on the outer section of the Australian continental shelf, where water depths are 60 - 110 m. The seafloor along the majority of the pipeline route is gently sloping or undulating, with some steeply sloping sections, associated with subtidal shoals. These submerged shoals are carbonate mound structures, some of which rise to within 40 m of the surface. For the last 300 km to Darwin Harbour, depths follow a shallowing trend from 60 m.
3.2 Darwin and Darwin Harbour
Darwin Harbour is described as a large drowned river valley of about 1000 km2. It is made up of 3 arms which converge into a large embayment before flowing into the open sea. Two of the arms, East and Middle Arm, receive waters from the hinterland of Darwin and Palmerston, and deliver large volumes of water to the harbour during the wet season, creating estuarine conditions from January to April.
The coastline of the outer section of the harbour is comprised mainly of sandy beaches and rocky foreshores. Within the harbour, shores are characterised by extensive intertidal mud flats and mangroves. Corals exist in several areas within the harbour with the highest diversity occurring in the outer section.
Most of the harbour waters are less than 10 metres deep, however there are locations within the channels of Middle and East Arms that reach 20 m in depth at low water. The tidal range in Darwin Harbour reaches 8 metres. Sediments of the seabed vary from fine muds to coarse sands, shell grit and coral rubble. Hard rock outcrops are also present.
Many wrecks are found within Darwin Harbour. These include ships and aircraft from WWII, wrecks from cyclones and deliberately scuttled boats for use as fishing and diving sites.
Wickham Point, the location of the LNG plant, comprises two "islands" of terrestrial vegetation at the tip of the peninsula between East and Middle Arms. The plant will be built on the westernmost island of Wickham Point. This island is entirely surrounded by intertidal mangroves that are partially or completely inundated at high tide.
3.3 Areas of conservation significance
The pipeline route will traverse the proposed Beagle Gulf Marine Park to the north of Darwin Harbour. The management plan for the Marine Park is expected to allow for the construction and usage of the pipeline.
Several areas within Darwin Harbour are listed on the Register of the National Estate and the NT Heritage Register. These include the Channel Island Conservation Reserve, Channel Island Corals (between Channel Island and the mainland) and the Darwin Foreshores (outer coastline of the harbour).
Other areas of conservation significance include the proposed Charles Darwin National Park, Casuarina Coastal Reserve, Blackmore River Conservation Reserve, East Point Aquatic Life Reserve and Doctors Gully Aquatic Life Reserve.
Darwin Harbour has been listed in "A Directory of Important Wetlands in Australia" published by the Australian Nature Conservation Agency in 1993. The Darwin Harbour (Mangrove) Wetlands have also been nominated for inclusion in the National Estate Register.
Wickham Point has a number of archaeological sites located either within or adjacent to the proposed plant area. Six sites are prehistoric shell middens, two are WWII historic sites and one is the remains of the "Mud Island" leprosarium. Several historic shipwrecks are located in Darwin Harbour, including the WWII wrecks of the USAT Mauna Loa, USAT Meigs and SS Ellengowan. The Japanese submarine 1-124, a declared war grave, is located offshore within 1500m of the pipeline.
3.4 Socio-economic environment
The total population in the Darwin region is about 95,000. The nearest community to Wickham Point is Palmerston, with a population of about 13,000, located approximately 25 km to the east by road.
At present, there is little heavy industry in the Darwin region and Wickham Point has been identified as the preferred site for future industrial development. Other major developments are occurring in the East Arm region. East Arm Port, currently under construction, will be the new location for the various port activities carried out at the Port of Darwin. Other important industries in the Northern Territory are commercial fishing, tourism, the pastoral industry, mining and defence.
Darwin Harbour is widely used for a variety of activities. Commercial fishing effort is low in the harbour whereas recreational fishing is a well established activity, concentrating on mud crabs, barramundi and a wide variety of reef fish. The expanding aquaculture activities focus on prawns and pearl oysters. Scuba diving and boating are other important recreational activities that occur in the harbour.
Submarine telecommunication and power cables cross the harbour from Darwin to Mandorah and offshore there is a large military exercise area. Wickham Point lies directly under the flight path of the north-south runway of Darwin Airport, which is used by the smaller private and commercial aircraft.
Wickham Point and the surrounding sea bed is considered significant to the Larakia people and the area is subject to two claims filed under the Native Title Act 1993.