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National Water Account 2017

Daly: Geographic information

The Daly region is highly groundwater dependent, and one of the few perennial river systems in northern Australia. As such, the region's rivers are very important for environmental, cultural and recreational purposes. Water in the region is currently used for a variety of agricultural and industrial purposes. The region has been identified for potential increased development. 

 

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)

The Daly region is located in northern Australia approximately 200 km south of Darwin. The boundary of the region is physically defined by the Daly River surface water catchment (Figure R1).

 

Figure R1 Contextual map of the Daly region
Figure R1 Contextual map of the Daly region

 

The Katherine River is the main tributary to the Daly River, while the Flora, Fergusson, Edith, King, Dry, and Douglas rivers are also important contributors. The Daly River discharges into the Timor Sea in the northwest of the region. To the east of the region, in the upper reaches of the Katherine River, is the Arnhem Land plateau.

Key groundwater stores within the region include the Oolloo, Jinduckin, and Tindall aquifers. These aquifers are a source of public and self-supply water. The aquifers discharge into many of the rivers within the region, providing dry season flow for parts of the river system and some culturally significant springs. Consequently, these rivers have strong environmental, cultural, and recreational significance.

The Daly region primarily contains areas of conservation and pastoralism but is also an important area for tourism. It includes large areas of Aboriginal freehold land. There are at least 12 discrete groups of Aboriginal people within the Daly region. These include the Wadjigiyn; Maranunngu; Malak Malak; Kamu; Warai; Nanggiwumerri; Wagiman; Wardaman; Dagoman; Jawoyn; Matngala; and Yangman peoples.

 

Region definition

The Daly region is physically defined by the Daly River surface water catchment boundary and includes all water resources within or beneath the physical area.

The region account includes water stored in and transactions related to:

Wetland, Northern Territory (istock © Catherine and Simon Gidz)

  • surface water storages in the region
  • rivers within the region
  • groundwater aquifers beneath the region, although a groundwater asset has not yet been defined.

The Daly region account excludes water stored in and transactions related to:

  • water held in pipes and infrastructure of the urban water system
  • off-channel water storages, such as farm dams, and rainwater tanks
  • water held in the landscape, such as soil moisture.

For more information regarding items in this water accounting report, please refer to the Water accounting policies note.

 

Land use

There are several towns in the Daly region. Katherine is the regional centre, while other towns include Pine Creek and Daly River (Nauiyu).

The Daly region has been recognised both for its high conservation values as well as its potential for further development of agriculture and mining. There are several parks in the region including Umbrawarra Gorge Nature Park, Nitmiluk National Park, Cutta Cutta Caves Nature Park, Douglas Hot Springs Nature Park, and some areas of Kakadu National Park (Figure R1). These areas provide environmental and cultural value and are also popular for tourism, fishing, camping, bushwalking, and other recreational activities.

Pastoralism, primarily beef cattle grazing, occurs extensively in the area. Horticultural crops grown in the region include sorghum, peanuts, and mangoes. There has recently been an increase in irrigated agriculture in the region, particularly sandalwood. Mining occurs sporadically throughout the region with several mines near the Pine Creek township, including the Frances Creek iron ore project, the Union Reefs gold mine, and the decommissioned Mt Todd gold mine.

The major land use activities in the Daly region are shown in Table R1 (Australian Bureau of Agricultural and Resource Economics and Sciences 2014).

 

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

 

Over 23% of the population in the Daly region is Aboriginal. The population includes people whose traditional country is in the Daly region and Aboriginal people who have moved to the region for economic and social reasons.  The Aboriginal population is often under-represented in census data because of the challenges of recording populations in remote regions (Northern Australia Indigenous Land and Sea Management Alliance 2012).

In the Oolloo aquifer-planning area, 24% of land ownership is recognised as Aboriginal Land Trust land under the Aboriginal Land Rights (Northern Territory) Act 1976. While current Aboriginal land ownership in the Tindall Aquifer plan area is 1%, the outcomes of two registered native title claims may significantly influence the extent of land ownership in the future (Department of Natural Resources, Environment, the Arts and Sport [NRETAS] 2007).

 

Significant aquatic ecosystems

The Daly region contains three important wetlands as identified by the Northern Australia Sustainable Yields Project (NRETAS 2010) and shown in Figure R2:

  • Daly–Reynolds Floodplain-Estuary System: a major floodplain-tidal wetland system with the largest catchment of any major freshwater floodplain system in the Northern Territory
  • Daly River Middle Reaches: a permanent freshwater river
  • Katherine River Gorge: a major permanent river-pool system situated in one of the larger gorges in the Northern Territory.

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 (Figure R2).

 

Figure R2 Map of significant wetlands in the Daly region
Figure R2 Significant wetlands in the Daly region

 

Significant Indigenous cultural places and practices

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. A Malak Malak story about the Dreamtime origins of the Daly River reveals the way in which flowing water provides the basis for life and dispenses collective good and well-being.

In Wardaman mythology, the creative powers of the Rainbow Serpent are responsible for the waterscapes of the country. The rainbow serpents are recognised by Jawoyn and Wardaman cultural traditions as being 'important and potentially dangerous creation beings' that reside in 'permanent deep green pools, at springs, and at locations underground, particularly those associated with underground water'. 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 such as billabongs, and 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). Some of those ancestors were species that would be associated with water: black water hens, barramundi, frogs, freshwater sharks or crocodiles. Significant sites include 'rivers and creeks and their associated features, including gorges, waterfalls, plunge pools, waterholes, billabongs and springs, and areas away from river and creek beds such as seasonally inundated swampy areas and isolated rockholes and springs' (Cooper and Jackson 2008). 

Aboriginal people have common-law rights to maintain customary use and access to places and resources, including water. Significant cultural water sites falling under the definition of sacred site are protected under the Aboriginal Land Rights (Northern Territory) Act 1976 and Northern Territory Aboriginal Sacred Sites Act 1989. The Oolloo water-planning area, which covers the extent of the Oolloo aquifer (see Figure R6 below), includes 576 sites, of which 91 are recorded sites, 242 are registered sites and 243 are place names or archaeological sites (NRETAS 2012).

Jackson (2004) documented the extensive ethnobiological knowledge of the Malak Malak and Matngala peoples from the Daly region and their use of a diversity of plants, animals, and fish as well as fishing practices and land management activities. The Daly River Fish and Flows Project similarly documented the extensive knowledge of traditional owners in the Daly region of species and their environmental interactions. This included species' sensitivity to changes in water quality and quantity (CSIRO 2009a).

 

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. The water resources of the region are primarily used for public water supply and individual users in the agricultural and industrial sectors. The water resources are described in more detail in the Surface water and Groundwater sections below.

 

Surface water

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. It was originally developed for water supply to nearby mining developments. The capacity of the Copperfield Dam is approximately 413 ML.

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.

 

Rivers

The Daly River and its tributaries form one of the Northern Territory's largest river systems and one of the few in northern Australia to have perennial flow. The main tributary of the Daly River is the Katherine River. Other important tributaries are the Flora, Fergusson, Edith, and Douglas rivers. The King and Dry rivers, located in the southern part of the region, have large catchments but are in a lower rainfall area and contribute little to the dry season flow of the Daly River (Department of Lands, Planning and Environment 1998).

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 (Figure R3).

The gauging stations used to represent the general seasonal flow patterns of the Daly region in Figure R3 are located along the Katherine River at the Railway Bridge (Station G8140001) and the Daly River at Mount Nancar (Station G8140040) and are shown in Figure R4. There are other gauging stations in the Daly region although they are not shown in this map.

Figure R3  Graph of mean monthly flows along the Katherine and Daly rivers and mean monthly rainfall for the Daly region
Figure R3 Mean monthly flows along the Katherine and Daly rivers and mean monthly rainfall for the Daly region

 

Figure R4 Map of gauging stations along the Katherine and Daly rivers within the Daly region
Figure R4 Gauging stations along the Katherine and Daly rivers within the Daly region

 

The Katherine River headwaters are formed in the high relief sandstone escarpment country of the Arnhem Land plateau, approximately 150 km upstream of the town of Katherine. The river drops down from the escarpment through a series of sandstone gorges that make up the Katherine Gorge before reaching the lowlands upstream of Katherine. Approximately 60 km west of Katherine, the Katherine and Flora rivers join to become the Daly River that then continues westward for 354 km before entering the Timor Sea at Anson Bay (Department of Lands, Planning and Environment 1998).

Water from the Tindall aquifer discharges into many of the rivers within the Daly region, including the Katherine, Flora, and Douglas rivers (NRETAS 2009) and provides flow into the rivers throughout the dry season. The perennial rivers of the region support endemic wildlife, irrigation development, and domestic and stock use, and are of high cultural value. Dry season flow is mostly dominated by input of groundwater from the two underlying limestone aquifers, Tindall and Oolloo (see Figure R5 below), which have an intervening siltstone aquitard.

 

Groundwater

Underlying the Daly River surface water catchment are the Daly basin aquifers, made up of four layered geological formations. The upper most aquifer is the Florina and is the youngest and smallest of the four. Below the Florina formation are the Oolloo, Jinduckin, and Tindall aquifers (Figure R5). There are also several smaller, local, low-yielding aquifers in the region that are not shown in Figure R5 but are important for local water supply, mainly for stock and domestic use.

 

Figure R5 Map of groundwater aquifers in the Daly region
Figure R5 Groundwater aquifers in the Daly region

 

Figure R6  Cross-section diagram of groundwater aquifers in the Daly region
Figure R6 Cross-section diagram of groundwater aquifers in the Daly region
 

 

Figure R6 shows a cross-section of the aquifers of the Daly region. Both the Oolloo and Tindall aquifers are largely limestone and are substantially fractured and cavernous. Large volumes of water can be stored within the fractures of these types of geologic formations and water flows relatively easily through them, resulting in the potential to extract water from these aquifers at high rates of 50L/s or more (NRETAS 2009a). The Tindall aquifer also underlies the adjoining Roper catchment.

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). These areas are described as unconfined zones of the Tindall aquifer (NRETAS 2009a). The Jinduckin formation is made up of siltstone, which is largely impermeable to water.