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National Water Account 2018

Daly: Geographic information

  • The Daly region is highly groundwater dependent, and one of the few perennial river systems in northern Australia.
  • The rivers are very important for environmental, cultural and recreational purposes.
  • Water in the region is primarily used for agricultural purposes.

Map showing the following summary information for the Daly region: water use—0.2 % of Australia's water use; land use—50% of the region used for grazing; ecosystems—2 important wetlands with strong cultural significance; water resources—80% of water is sourced from groundwater. 

For further geographic information about the region scroll down this page or click on the links below:

 

General description

Area: 53,708 km²

Population: 12,000 (Australian Bureau of Statistics 2016)

 

Map showing the key water features of the Daly region. The Daly region is in the Top End of the Northern Territory and its boundary is defined by the Daly River surface water catchment. The major town of Katherine is near the centre of the region along the Katherine River. Other towns in the region include Pine Creek in the north and Daly River in the northwest about 70 km upstream of the mouth of the Daly River. Conservation areas include Nitmiluk National Park and part of Kakadu National Park in the region's northeast, Tjuwaliyn (Douglas) Hot Springs Park and Umbrawarra Gorge Nature Park in the north, and Flora River and Cutta Cutta Caves nature parks in the central part of the region.
Figure R1 Contextual map of the Daly region

 

  • The Daly region is located in northern Australia and is physically defined by the Daly River surface water catchment.
  • Aquifers discharge into many of the rivers within the region, providing dry season flow for parts of the river system. Consequently, these rivers have strong environmental, cultural, and recreational significance.
  • Only 0.2% of Australia's water use occurs in the region. Most of the water use is from groundwater stores for agricultural purposes.

 

Land use

Table R1 Major land use activities in the Daly region
Land use activityArea (km2)Total area (%)
Grazing28,02652
Conservation and natural environments21,79441
Wetland2,0474
Dryland agriculture1,3432
Urban312<1
Irrigated agriculture99<1
Other intensive uses79<0.1
Mining10<0.1
Total53,710

 

  • More than 50% of the region is for pastoralism, primarily beef cattle grazing.
  • 41% of the region contains conservation areas, including nature reserves and national parks.
  • Katherine is the regional centre; other towns include Pine Creek and Daly River (Nauiyu).

 

Significant aquatic ecosystems

Map showing the locations of significant wetlands within the Daly region. There are three nationally-important wetlands in the region: Katherine Gorge, a 40 km reach of the Katherine River that lies within Nitmiluk National Park in the regions' northeast; Daly-Reynolds Floodplain-Estuary System in the northwest that encompasses the coastal floodplain area around the mouth of the Daly River; and Daly River Middle Reaches, about a 60 km reach of the Daly River upstream of the coastal floodplain. The southern-most part of the Ramsar-listed Kakadu National Park lies within the northeastern part of the region upstream of Katherine Gorge.
Figure R2 Significant wetlands in the Daly region

 

  • The region contains three important wetlands as identified by the Northern Australia Sustainable Yields Project (NRETAS 2010).
  • Each of these wetlands is home to a variety of aquatic and birdlife, providing dry season refuge for waterbirds including magpie geese, herons, and allies.
  • The southern part of Kakadu National Park, which lies within the Daly region, is a Ramsar site.

 

Significant Indigenous cultural places and practices

  • There are at least 12 discrete groups of Aboriginal people within the Daly region. For Aboriginal people in the region, water is a sacred and elemental source and a symbol of life (Langton 2006).
  • The quality of water as 'living' or as having 'life-giving' qualities is conveyed through Dreamtime stories. In Wardaman mythology, the creative powers of the Rainbow Serpent are responsible for the waterscapes of the country. They are believed to be the drivers of the hydrological cycle and bringer of the monsoon floods (Cooper and Jackson 2008).
  • Many of the sacred sites in the Daly River region are associated with rivers, tributaries, and groundwater-dependent ecosystems; the Daly River itself is a significant ceremonial track. Sacred sites are landscape features 'created either by the metamorphosis of Dreamtime figures into rocks, boulders, trees, etc., or by the action of such an ancestor, or ancestors, sometimes when interacting with each other' (Northern Land Council 2004).
  • Aboriginal people have common-law rights to maintain customary use and access to places and resources, including water.

 

Water resources

  • Surface water (rivers) and groundwater are the primary water resources in the Daly region. Both water resources are used to support the main water users in the region and are strongly interconnected.

 

Groundwater

Map showing the locations of the four key groundwater aquifers within the Daly region. The aquifers are layered and are aligned in a northwest direction beneath the main channel of the Daly River. The largest and deepest aquifer is the Tindall Limestone, which extends from the northwest of the region to beyond the southeastern boundary. Above that lies the Jinduckin Formation, which extends from the northwest to the eastern boundary; the Oolloo Dolostone in the central part of the region; and the Florina Formation, the smallest and upper most aquifer in the central part of the region.
Figure R3 Groundwater aquifers in the Daly region

 

A simplified three-dimensional cross-section image of the Daly region's groundwater aquifers. The section is taken over the Daly River in the central part of the region. The image shows that the region's aquifers are made up of four layered geological formations beneath the main channel of the Daly River. The uppermost layer is the Florina Formation. Beneath that lies the Oolloo Dolostone—massive unit and bedded unit—followed by the Jinduckin Formation. The largest and deepest aquifer is the Tindall Limestone, which sits above a layer of basalt.
Figure R4 Cross-section diagram of groundwater aquifers in the Daly region
 

 

  • Underlying the Daly River surface water catchment are the Daly basin aquifers, made up of four layered geological formations.
  • The Oolloo and Tindall aquifers are largely limestone and are substantially fractured and cavernous. Large volumes of water can be stored within these formations and water flows relatively easily through them, resulting in the potential to extract water from these aquifers at high rates.
  • The Tindall aquifer is confined by the Jinduckin and Oolloo dolostone formations as water does not infiltrate through them to the Tindall aquifer. Recharge to the Tindall aquifer only occurs in areas where it is in direct contact with the ground surface (e.g., near Katherine).
  • The Jinduckin formation is made up of siltstone, which is largely impermeable to water. The upper most aquifer is the Florina and is the youngest and smallest of the four.
  • There are also several smaller, local, low-yielding aquifers in the region, where water is mainly used for stock and domestic use.

 

Surface water

Rivers

  • The Daly River and its tributaries form one of the Northern Territory's larger river systems and one of the few in northern Australia to have perennial flow.
  • The Daly River discharges into the Timor Sea in the northwest of the region; the main tributary of the Daly River is the Katherine River.

 

Map showing the locations of key gauging stations along the main rivers within the Daly region. Katherine River at the Railway Bridge, station number G8140001, in the central part of the region near the town of Katherine, and Daly River at Mount Nancar, station number G8140040, in the northwest part of the region near the town of Nauiyu and just upstream of the Daly River's tidal limit.
Figure R5 Gauging stations along the Katherine and Daly rivers within the Daly region

 

Figure R6  Graph of mean monthly flows along the Katherine and Daly rivers and mean monthly rainfall for the Daly region
Figure R6 Mean monthly flows along the Katherine and Daly rivers and mean monthly rainfall for the Daly region

 

  • Seasonal flow characteristics of rivers within the Daly region reflect the annual rainfall pattern of the region. Most of the rainfall occurs during the wet season (November–April). Consequently, most of the streamflow within the region occurs between January and May.
  • Dry season flow in these rivers is mostly dominated by input of groundwater from the two underlying limestone aquifers, Tindall and Oolloo (see Figure R3 above), which have an intervening siltstone aquitard. The perennial rivers of the region support endemic wildlife, irrigation development, and domestic and stock use, and are of high cultural value.

 

Storages

  • Copperfield Dam is the region's largest surface water storage and is used for public water supply to the nearby town of Pine Creek.
  • There are also two weirs upstream of the town of Katherine on the Katherine River: Knott's Crossing and Donkey Camp Pool. These weirs were developed for surface water supply to Katherine.