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Estuary Assessment 2000: Northern Territory

Specify a region: -- select region -- Adelaide River Bathurst and Melville Islands Blyth River Buckingham River Calvert River East Alligator River Finniss River Fitzmaurice River Goomadeer River Goyder River Groote Eylandt Keep River Koolatong River Limmen Bight River Liverpool River Mary River (NT) McArthur River Moyle River Nicholson River Ord River Robinson River Roper River Rosie River Settlement Creek South Alligator River Towns River Victoria River Walker River Wildman River

Northern Territory

Key findings

 

Key messages

• The majority of estuaries in the Northern Territory are in near-pristine condition, primarily a result of low population pressure and reflecting minimal catchment and estuarine shoreline development. As a result, the focus of estuarine management in the Northern Territory is to maintain and protect estuarine condition, rather than remediation.

Key needs

• Information on the physical, chemical and biotic processes, as well as the habitat requirements of estuarine flora and fauna.
• Understanding and management of the links between catchment activities and estuarine ecological health.
• Management tools that predict the impact of catchment, shoreline and other activities on estuarine health would assist planning and management.
• Research and management activities (including monitoring) for priority estuaries.

Management arrangements

Two Northern Territory government agencies share the responsibility for various aspects of estuarine management. These are the:

• Department of Infrastructure, Planning and Environment (responsible for planning developments, planning approvals, natural resource management, water quality, water resource planning, waste water discharge licensing, waste management and pollution control, habitat mapping, management of coastal reserves, and shoreline infrastructure); and
• Department of Business, Industry and Resource Development (responsible for fisheries, and in partnership with the Australian Quarantine Inspection Service, marine pest management).

The management of estuaries is affected by 22 Northern Territory Acts that deal with issues such as heritage, conservation, biodiversity, public health, fisheries and ports and chemicals.

Of these, the Water Act 1992 (NT), has the most direct involvement on water quality issues in fresh and marine waters, while the Planning Act 1993 (NT) and Waste Management and Pollution Control Act 1994 (NT) are important Acts that affect land use and waste management, respectively. The Department of Infrastructure, Planning and Environment administers all three Acts and is involved in the monitoring of waters and the catchment. The Water Act 1992 (NT) encompasses the management of estuarine waters as well as all freshwater discharges to estuaries. The Act regulates the discharge of pollutants to waters through the issue of waste discharge licenses and the use of fresh and marine waters for commercial activities through the issue of extraction permits. Relevant Commonwealth legislation, specific to the Northern Territory, includes the Aboriginal Land Rights (Northern Territory) Act 1976 (Cwlth) the legislative basis for freehold title to land, including estuaries, being granted to Indigenous occupants.

Policies

The declaration of beneficial uses (environmental values) for estuarine and catchment waters is a key policy instrument. Beneficial uses have been declared for Darwin Harbour and its major waterways (Darwin, Blackmore, Elizabeth, Howard Rivers), Fogg Bay, Gove Harbour, the McArthur River, Shoal Bay, Vernon Islands and Groote Eylandt. The uses include aquatic ecosystem protection, recreational water quality and aesthetics.

The Darwin Harbour Strategic Plan for beneficial uses has been developed, in consultation with the community. The plan provides a management framework that identifies key environmental objectives that ensure the declared beneficial uses are maintained.

A Mangrove Management Report for the Northern Territory had been compiled. It outlines the state of knowledge of mangrove ecosystems in the Northern Territory and includes a summary of the current and future directions for mangrove research.

The Department of Business, Industry and Resource Development implements exclusion zones for the protection of coastal habitat and commercial fisheries. In collaboration with Queensland Department of Primary Industries, it has undertaken extensive mapping of coastal mud crab habitat.

Community initiatives

Community-based mangrove monitoring activities are in place for areas around Darwin Harbour. Waterwatch, Bushcare, Landcare and Coastcare are raising awareness of catchment activities that affect estuarine health.

State priorities

• Support and facilitate the establishment of a sustainable aquaculture industry in the Northern Territory. The near-pristine condition of the Northern Territory's estuaries and their warm water temperatures are advantageous to aquaculture.
• Maintenance of sustainable commercial and recreational fisheries, building on the near-pristine condition of the estuaries.
• Estuarine and catchment management to maintain their ecological integrity, as evidenced by the work under way to manage Darwin Harbour.

Around the Territory

Northern Territory estuaries are all located in the wet/dry tropics of Northern Australia, which experience wet season rainfall during the summer months. Coastal catchments discharge to the Gulf of Carpentaria to the east, the Arafura Sea to the north and the Timor Sea to the west. In the north, monsoonal activity during the wet season is responsible for high rainfall. In the eastern and western regions a combination of weaker monsoonal effects and cyclonic activity influences annual rainfall. Flows in rivers discharging to estuaries are highly variable. Depending on the extent of the monsoon fronts and cyclonic activity the magnitude of annual floods varies between years. During the dry season freshwater discharge from rivers to estuaries often ceases.

A feature of Northern Territory estuaries is the extensive mangrove habitats and macro-tidal regime along the northern and western coastlines. The estuaries provide significant habitat for some of the densest populations of estuarine crocodiles in the world, roosting areas for sea and water birds, and habitat for tropical marine organisms. These estuaries also provide research opportunities as reference sites to better understand natural estuarine processes as a framework for improving management of modified estuaries.

With the exception of the Darwin region and Nhulunbuy in the northeast, the Northern Territory coastline is sparsely populated, with a large proportion of estuaries remote and inaccessible by land. The population in these areas consists of Indigenous communities and the homesteads of pastoral properties. Approximately half the Northern Territory coastline is Indigenous land, with the remainder of the coastline either freehold or pastoral lease. The dominant and often only land use in the catchments is grazing. Northern Territory estuaries are valuable for traditional harvesting, eco-tourism, and pearling as well as commercial and recreational fisheries. The estuaries in the Gulf of Carpentaria support the nationally important Gulf prawn and finfish fisheries.

Further information

For further information about the Australia-wide assessment, please contact: National Land and Water Resources Audit Phone: 02 6263 6035 Email: info@nlwra.gov.au

CRC Coastal Zone, Estuary and Waterway Management

Link to the Map Maker to make a map using this information.

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