The Victoria River Water 
Resource Assessment

Summary report

THE VICTORIA RIVER WATER RESOURCE 
ASSESSMENT WAS PREPARED BY CSIRO 
FOR THE NATIONAL WATER GRID



About this report

Skinner Point, a sandstone 
mesa above a level alluvial 
loamy plain, which is shallow 
and rocky in places.

CSIRO has completed, for the Australian Government, an investigation of 
the opportunities and risks of water resource development in the catchment 
of the Victoria River in the Northern Territory (NT). The key findings of the 
Assessment for the Victoria catchment are presented here. Readers are 
referred to the more comprehensive catchment and companion technical 
reports for more detailed information.

The physical attributes of the study area would allow the area of land 
under irrigation to be increased from less than 0.001% to 0.6% of the 
catchment area. In reality, the nature and scale of future development of 
irrigation would depend heavily upon community and government values 
and acceptance of potential impacts to water‑dependent ecosystems. 
The outcome of no change in land use or water resource development is 
also valid. The baseline information collected as part of the Assessment 
can inform future regional‑scale and on-Country planning.

CSIRO acknowledges the Traditional Owners of the lands, seas and waters of the area that we live and work 
on across Australia. We acknowledge their continuing connection to their culture and pay our respects to 
their Elders past and present.



Key features of the Victoria catchment.

The Victoria catchment

The Victoria catchment has an area of approximately 
82,400 km2. It flows into the Joseph Bonaparte Gulf in 
the Timor Sea which is an important part of northern 
Australia’s marine environment with high ecological and 
economic values. Within the catchment, 31% of the land 
is Aboriginal freehold tenure, which includes the 16% of 
the catchment which is national park. The Bradshaw Field 
Training Area occupies 7%, to which access is restricted. 
The dominant land use across the Victoria catchment is 
grazing of beef cattle on native rangelands (62% of the 
catchment area). There is less than 100 ha of irrigated 
agriculture, which is about 0.001% of the catchment. 
There are no active mines in the study area, although 
known mineral occurrences include barite, copper, 
lead and prehnite. Mining and petroleum exploration 
licences cover 61% of the study area. The catchment has 
a population of approximately 1600 people, of whom 
about 75% are Indigenous Australians. In contrast, 
Indigenous Australians make up 25% of the population of 
the NT and 3% of Australia as a whole. There are no large 
urban centres. The population density of the Victoria 
catchment (1 person per 50 km2) is one of the lowest in 
Australia, and communities in the catchment are ranked 
as being among the most disadvantaged in Australia. 
Business and tourist visitation to the Victoria catchment is 
highly seasonal and modest in number (~27,000/year) and 
valued at less than $20 million/year. Tourists to the Victoria 
catchment area are mostly classified as self-drive tourists.

Indigenous Peoples have continuously occupied and 
managed the Victoria catchment for tens of thousands 
of years. They retain significant and growing rights and 
interests in land and water resources, including crucial roles 
in water and development planning and as co-investors 
in future development. Key language groups include the 
Gurindji, Ngarinyman, Ngaliwurru, Nungali, Miriuwung 
and Gajerrong. A number of related groups and subgroups 
occur within the traditional lands of these regional 
language groups.

The Victoria River, at approximately 560 km in length, is 
the second longest river with permanent water in the NT. 
However, unlike the NT’s better known Daly and Roper 
rivers, late dry-season flows in the Victoria River are small, 
and most permanent waterholes are likely to be a result of 
residual flow from the previous wet season. The Victoria 
River has the second‑largest median annual streamflow 
(5370 GL) of any river in the NT, and the fourth largest 
in northern Australia west of the Great Dividing Range. 



Approximately 93% of the streamflow in the Victoria 
catchment occurs between January and March. The Victoria 
catchment is unregulated (i.e. it has no dams or weirs) 
and existing annual licensed surface water extractions are 
approximately 2 GL (0.04% of median annual discharge). 
However, the study area includes a large earth embankment 
gully dam (35 GL capacity) in the catchment of Forsyth 
Creek, which flows into Joseph Bonaparte Gulf adjacent to 
the Victoria River. Current annual licensed surface water 
extractions from the catchment of Forsyth Creek are 150 GL.

With irrigation, the Victoria catchment has a climate that is 
suitable for a range of annual and perennial horticulture, 
and broadacre crops and forages. The regions in the 
Victoria catchment with the most potential for irrigated 
agriculture are areas adjacent to the upper West Baines 
River and the Victoria and Wickham rivers downstream of 
Yarralin, the sandy and loamy soils and clay soils north‑east 
of Top Springs, and the extensive sandy and loamy 
soils along the south-eastern margin of the catchment. 
The opportunities and risks of development in each of 
these regions are starkly different. Opportunities for 
irrigated agriculture along the Wickham and Victoria rivers 
are generally limited by the availability of suitable soil and 
topography adjacent to the rivers, whereas along the West 
Baines River and near Top Springs and along the eastern 
margins of the catchment, irrigated agriculture is limited 
by available water.

The cracking clay soils on the broad alluvial plains of 
the West Baines River upstream of the Victoria Highway 
(54,000 ha) offer the greatest potential for broadacre 
irrigation in the Victoria catchment. Note that this estimate 
of soil area, and the ones below, includes land considered 
suitable but with limitations and would require careful 
soil management. Along the West Baines River upstream 
of the highway, it is physically possible to extract up to 
100 GL of surface water in 75% of years, which is sufficient 
water to irrigate up to 7000 ha of dry-season broadacre 
crops. Further downstream there is an additional 50,000 ha 
of cracking clay soils; however, the suitability of soil for 
irrigated agriculture during the wet-season becomes 
increasingly marginal due to increasing seasonal wetness 
(leading to waterlogging and trafficability issues) and 
flooding, so enterprises would become increasingly less 
commercially viable. Nonetheless, it would be physically 
possible to extract an additional 300 GL of surface water 
in 75% of years from the West Baines River below the 
highway crossing. The proximity of West Baines to the 
Victoria Highway, and to the service town and cotton 
gin in Kununurra in WA, may offer an advantage to new 
irrigation developments relative to many other parts of 
northern Australia. 



Less expansive opportunities for water harvesting exist 
adjacent (within 5 km) to the Wickham and Victoria 
rivers (22,000 ha), limited by where ringtanks for storing 
water can be constructed on heavier alluvial clay soils. 
The commercial viability of water harvesting enterprises 
along these river reaches would be highly variable due 
to increasing elevation away from the river and/or the 
width of sandy and loamy levee soils, both of which 
increase piping and pumping costs. Notwithstanding this, 
and including the Baines River, it is physically possible, 
although not necessarily commercially viable, to extract 
up to 690 GL of surface water in 75% of years from the 
major rivers in the Victoria catchment. That amount is 
sufficient water to irrigate up to 50,000 ha of alluvial clay 
and sandy and loamy soils where they exist as contiguous 
areas. This volume of water extraction would result in a 
reduction in mean and median annual discharges from the 
Victoria River into the Joseph Bonaparte Gulf of 9% and 
12%, respectively. Based on historical trends in irrigation 
development and existing surface water plans across 
northern Australia, more-modest scales of surface water 
development, for example, 10 to 150 GL (i.e. ~0.2% to ~3% 
of median annual discharge from the Victoria River), would 
be more likely. 

North-east of Top Springs and along the eastern 
and southern margins of the Victoria catchment are 
approximately 62,000 and 695,000 ha, respectively, of 
well-drained sandy and loamy soils that are potentially 
suitable, with considerable limitations, for irrigated annual 
and perennial horticultural crops under dry-season trickle 
irrigation. However, there is only sufficient surface water to 
irrigate less than 0.3% of this area. Due to the absence of 
reliable surface water in this part of the study area, water 
would need to be sourced from the regional‑scale Cambrian 
Limestone Aquifer (CLA), which underlies the eastern 
margin of the Victoria catchment. It is physically possible to 
extract 10 GL of groundwater each year from this part of the 
CLA, which is sufficient water to irrigate 1000 to 2000 ha of 
mixed broadacre cropping and horticulture. However, this 
part of the catchment is particularly remote, and transport 
costs pose a major constraint to irrigation enterprises in 
this region. Commercially viable opportunities would most 
likely be limited to annual horticulture targeting winter 
supply gaps in southern markets, such as from a wet-season 
planting (December to early March), which is possible on 
these well-drained soils. 

Jasper Gorge in Judbarra National Park is a key tourist attraction in the Victoria catchment.



Irrigated agriculture and aquaculture in the Victoria 
catchment are only likely to be financially viable where 
there is an alignment of good prices for high-value produce 
and market advantages. This makes achieving scale 
challenging. Other factors include availability of suitable 
markets for the products, investment in fundamental 
infrastructure such as all-weather roads and bridges, and 
land tenure arrangements that support development. 
New agricultural developments in the study area are most 
likely to start irrigating broadacre crops on heavier clay 
soils before progressing to higher-value and higher-input 
enterprises, such as horticulture on sandy and loamy soils, 
as farmers build confidence in their skills and expertise in 
this largely greenfield region. 

Along the very remote coastal margins of the study 
area, about 93,000 ha of land is suitable for prawn and 
barramundi aquaculture, using earthen ponds.

Growing irrigated forages or hay to feed cattle to be turned 
off at a younger age is unlikely to be financially viable. 
Feeding forages or hay increases beef production and total 
income, but increased costs mean that gross margins would 
be less than baseline cattle operations, and the high capital 
outlay would in most cases be prohibitive. Rainfed cropping 
in the catchment is likely to be opportunistic (i.e. only 
possible when suitable conditions allow) and depend upon 
farmers’ appetite for risk and future local demand.

The total annual economic activity (direct and indirect) 
generated from 10,000 ha of irrigated mixed broadacre 
(65%) and horticulture (35%) agriculture in the 
Victoria catchment could potentially contribute up to 
$280 million, supporting up to 200 full-time-equivalent 
jobs. Economic data from the NT indicate benefits 
arising from agriculture developments have been heavily 
skewed to non‑Indigenous households relative to 
Indigenous households. 

The potential area of land actually developed for 
irrigated agriculture based on surface water and/or 
groundwater will depend heavily upon community and 
government values, acceptance of potential impacts to 
water‑dependent ecosystems and existing groundwater 
users, the profitability of irrigated agricultural enterprises 
in the Victoria catchment, and those who would 
economically benefit.

Changes to streamflow under projected drier future 
climates are likely to be considerably greater than changes 
that would result from plausible groundwater and surface 
water developments. Of the global climate models 
examined, 28% projected a drier future climate over the 
Victoria catchment and 47% projected ‘little change’. 
The adopted future dry climate was based upon a global 
climate model that, in terms of mean precipitation, was 
7% drier than the historical climate. Using this as an input, 
it was found that modelled reduction in median annual 
streamflow projected to 2060 at the Victoria River mouth 
was 25%. This value exceeded the modelled reduction in 
median annual streamflow under the largest potential 
water harvesting development scenarios (12%), assuming 
a historical climate.

The Victoria River, although not pristine, has many 
unique characteristics and valuable ecological assets, 
which support existing industries such as commercial and 
recreational fishing. Whether based on groundwater or 
offstream storage, irrigated agricultural development has a 
wide range of potential benefits and risks that differentially 
intersect diverse stakeholder views on ecology, economy 
and culture.

The detailed reports upon which this summary is based 
provide information that can be used to help consider the 
trade-offs from potential developments.

Sampling soil along the West Baines River.



The Victoria Highway, the main transport link between Darwin 
and Kununurra, runs through the town of Timber Creek.



Overview of the 
Victoria catchment

The Victoria catchment sits inside the Australian savanna biome, the world’s 
largest intact tropical savanna, and like much of Australia’s north has 
free‑flowing rivers.

The Victoria catchment has 
a highly variable climate

Northern Australia’s tropical climate is notable for the 
extremely high variability of rainfall between seasons 
and especially between years. This has major implications 
for evaluating and managing risks to development, 
infrastructure and industry.

The climate of the Victoria catchment is hot and 
semi-arid. Generally, the Victoria catchment 
is a water-limited environment, so effective 
methods for capturing, storing and using water 
are critical.

• The mean and median annual rainfall amounts – 
averaged across the Victoria catchment – are 681 mm 
and 690 mm, respectively. A strong rainfall gradient runs 
from the northernmost tip (1050 mm annual median) 
to the southernmost part (410 mm annual median) of 
the catchment.
• Averaged across the catchment, 5% of the rainfall occurs 
in the dry season (May to October). Median annual 
dry‑season rainfall ranges from 18 mm in the west to 
34 mm in the north.
• Annual rainfall totals in the Victoria catchment are 
highly variable. Annual totals are approximately 1.3 times 
more variable than in comparable parts of the world. 
Using Kalkarindji as an example, between 1890 and 2022, 
the highest annual rainfall (1204 mm in the 2000–2001 
water year (1 September to 31 August)) was nearly eight 
times the lowest annual rainfall (159 mm in 1953–1954).


The seasonality of rainfall presents 
opportunities and challenges for both 
wet- and dry‑season cropping.

• Information about water availability (i.e. soil water 
and water in storages) helps minimise risk when it is 
known ahead of important agricultural decisions – 
before planting time for most dry-season crops. Such 
information allows farmers to manage risk by choosing 
crops that optimise use of the available water or by 
deciding to forego cropping for a season.




Rainfall is difficult to store.

• Mean annual potential evaporation is higher than 
rainfall, exceeding 1900 mm over the entire catchment. 
Unlike rainfall, potential evaporation does not exhibit a 
strong gradient across the catchment. 
• Large farm-scale ringtanks lose about 30% to 50% of 
their water to evaporation and seepage between April 
and October. Deeper farm-scale gully dams lose about 
20% to 40% of their water over the same period. Using 
stored water early in the season is the most effective way 
to reduce these losses.


The Victoria catchment is less exposed to 
cyclonic winds than are most other northerly 
draining catchments in Australia’s north. 

• Of the 53 consecutive cyclone seasons prior to 2021–22, 
the Victoria catchment had no tropical cyclones in 72% 
of those seasons, had one cyclone in 22% of seasons and 
two cyclones in 6% of seasons. 


An almost equal number of global climate 
models project a drier future climate and 
a wetter future climate for the Victoria 
catchment. Consequently it is prudent to plan 
for water scarcity.

• For the Victoria catchment, 28% of climate models 
project a drier future, 25% project a wetter future and 
47% project a future within ±5% of the historical mean, 
indicating ‘little change’. Recent research indicates 
tropical cyclones will be fewer but more intense in the 
future, although uncertainties remain.
• Palaeoclimate records indicate past climates have 
been both wetter and drier over the past several 
thousand years.
• Climate and hydrology data that support short- to 
medium-term water resource planning should capture 
the full range of likely or plausible conditions and 
variability at different timescales, and particularly for 
periods when water is scarce. These are the periods that 
most affect businesses and the environment.
• Detailed scenario modelling and planning should be 
broader than just comparing results under the baseline 
climate to a single alternative future climate scenario.
• Future changes in temperature, vapour pressure 
deficit, solar radiation, wind speed and carbon dioxide 
concentrations will separately act to increase or decrease 
crop water demand and crop yield under irrigation 
in northern Australia. However, changes under future 
climates to the amount of irrigation water required 
and crop yield are likely to be modest compared to 
improvements arising from new crop varieties and 
technology over the next 40 years. Historically, these 
types of improvements have been difficult to predict, 
but they are potentially large.


Crimson finch are endemic 
to northern Australia and 
New Guinea and inhabit 
tall grasses and Pandanus 
adjacent to water sources.

The Victoria River is one of northern 
Australia’s largest free‑flowing rivers.



The Victoria River is one of northern 
Australia’s largest free-flowing rivers

At approximately 560 km in length, the Victoria 
River is the longest singularly named river in 
the NT with permanent water and it has the 
second‑largest median annual streamflow of any 
NT river. 

• The mean and median annual river discharges from the 
Victoria catchment into the Joseph Bonaparte Gulf are 
6990 and 5370 GL, respectively. A small proportion of 
very wet years bias the mean, which is 30% higher than 
the median annual discharge. 
• Modelled annual streamflow ranges from 800 to 
23,000 GL. The annual variability relative to the mean 
annual streamflow is comparable with other rivers 
in northern Australia of similar mean annual runoff 
(streamflow divided by catchment area), but the annual 
variability in runoff is two to three times greater than 
rivers from other parts of the world with similar climates.
• A unique characteristic of the Victoria River is that it 
has a 25 km wide mouth at Queens Channel, part of the 
Joseph Bonaparte Gulf.
• The Joseph Bonaparte Gulf region experiences some 
of the largest tides in the country. Tidal variation at 
the mouth of the Victoria River is up to 8 m, and tides 
propagate to just downstream of Timber Creek, about 
140 km upstream of Queens Channel.
• Approximately 54% of streamflow into the Victoria River 
comes from the large tributary rivers of the Baines (22%), 
Angalarri (8%), Gregory (4%), Wickham (9%), Armstrong 
(7%) and Camfield (4%) rivers.


The Victoria River and its major tributaries are 
largely ephemeral. Most of the water in the main 
river channel during the late dry season is the 
result of residual flow from the previous wet 
season, rather than groundwater.

• On average, approximately 93% of the streamflow in the 
Victoria catchment occurs between January and March. 
This is higher than the better known Daly (80%) and 
Roper (84%) rivers, both of which are groundwater fed, 
but is typical of many rivers across northern Australia.
• Mid-to-late dry-season streamflow in the Victoria 
River and most of its major tributaries is low, less than 
200 ML/day.
• Current licensed surface water extractions in the study 
area are approximately 152 GL/year; however, 150 GL is 
licensed in the catchment of Forsyth Creek, which flows 
into the Joseph Bonaparte Gulf adjacent to the Victoria 
River. Licensed surface water extractions from the 
catchment of the Victoria River are only about 2 GL/year 
(0.04% of median annual discharge).


Although the area of land frequently flooded 
in the Victoria catchment is proportionally less 
than that of many other catchments in northern 
Australia, the proximity of some Indigenous 
communities to the Victoria River makes them 
susceptible to large flood events.

• The incised nature of the Victoria River in its lower 
reaches means the most frequently flooded areas are 
the junctions of the Baines and Angalarri rivers with the 
Victoria River and a choke point on the Victoria River 
55 km upstream of Victoria River Roadhouse.
• The Victoria Highway, a critical transport artery with 
about 33,000 freight trailer movements each year, can 
become impassable due to flooding at times during the 
wet season. 
• Flood peaks typically take about 2 to 3 days to travel from 
Dashwood Crossing to Timber Creek at a mean speed 
of 3.4 km/h.
• Between 1953 and 2023 (70 years), there were 
80 ‘observed’ streamflow events that broke the 
banks of the Victoria River at Coolibah Homestead 
(25 km downstream of Victoria River Roadhouse). 
All occurred between September and May (inclusive), 
and about 91% of the events occurred between 
December and March (inclusive). 
• Of the ten events with the largest flood peak discharge 
at Coolibah Homestead, six occurred in March, three in 
February and one in December.
• In 2023, a large flood displaced the residents of the 
townships of Kalkarindji and Nitjpurru (Pigeon Hole) on the 
Victoria River for several months. Based on the observed 
record (1953 to 2023), this event had an annual exceedance 
probability (AEP) of 2.6% at Coolibah Homestead.
• Flooding is ecologically critical because it connects 
offstream wetlands to the main river channel, allowing 
the exchange of fauna, flora and nutrients to support the 
important ecological functions of wetlands.


Under a potential dry future climate 
(7% reduction in rainfall), median annual river 
discharge from the Victoria River into the Joseph 
Bonaparte Gulf is projected to decrease by 25%.



Historical (1910 to 2019) median annual streamflow and selected soils potentially suitable for irrigated agriculture. Inset shows 
flood inundation (between 2000 and 2022) based on Moderate Resolution Imaging Spectroradiometer (MODIS) satellite data in the 
Victoria catchment.



The Victoria catchment has 
many unique ecological 
characteristics and contains 
important species and habitats 

The Victoria catchment contains a significant 
diversity of species and habitats, including 
freshwater, terrestrial and marine assets 
of great cultural, conservation and 
commercial importance.

• Much of the natural environment of the Victoria 
catchment consists of rolling plains, mesas, escarpments 
and plateaux with savanna, spinifex, grasslands and 
woodlands. The catchment and surrounding marine 
environment contain a rich diversity of important 
ecological assets. The region is considered the 
transitional zone and boundary between the Kimberley 
and Top End ecological communities. 


The Victoria catchment is largely intact, 
but it is not pristine.

• Previous studies have rated the riverine habitat in 
the Victoria catchment as being of high or very high 
overall quality and largely intact. They identified the 
catchment as having high wilderness value and being 
predominantly unaffected by clearing or development, 
although ecological threatening processes operate. 
• Existing threatening processes include cattle grazing, 
roads, river crossings, and impacts from introduced 
species, including feral animals and weeds.
• Fishing in northern Australia is highly valuable, and the 
waters of the Victoria catchment and nearby marine 
zone contribute to important recreational, commercial 
and Indigenous catches, including barramundi, redleg 
banana prawn and a variety of other species.
• One of the most significant environmental threats to 
remote regions across northern Australia is that of 
introduced plants and animals. In the Victoria catchment, 
pig, water buffalo, cane toad and cat are among the 
invasive animals.
• Weed species of interest in and around the Victoria 
catchment include 20 species of national significance. 
Invasive plants of concern include gamba grass 
(Andropogon gayanus), para grass (Brachiaria mutica), 
giant sensitive plant (Mimosa pigra) and prickly acacia 
(Vachellia nilotica).


The Victoria catchment includes wetlands 
of national importance and other important 
habitats for biodiversity conservation.

• Protected areas in the Victoria catchment include one 
gazetted national park (Judbarra), a proposed extension 
to an existing national park (Keep River), two marine 
national parks (Joseph Bonaparte Gulf Marine Park 
and North Kimberley Marine Park (Western Australia), 
which is adjacent to the Joseph Bonaparte Gulf Marine 
Park and follows the Western Australian coastline to the 
NT border), two Indigenous Protected Areas and two 
Directory of Important Wetlands in Australia (DIWA) 
sites (Bradshaw Field Training Area and the Legune 
coastal floodplain).
• The Legune coastal floodplain is a wetland identified 
as an Important Bird and Biodiversity Area by 
Birdlife International. Surveys have recorded more 
than 15,000 individuals from over 45 species, 
including magpie goose (Anseranas semipalmata), 
brolga (Antigone rubicunda) and red-capped plover 
(Charadrius ruficapillus).
• The freshwater sections of the Victoria catchment 
include diverse habitats such as persistent and 
ephemeral rivers, anabranches, wetlands, floodplains 
and groundwater-dependent ecosystems.
• Riparian habitats that fringe the rivers and streams of the 
Victoria catchment have been rated as having moderate 
to high tree cover and structural diversity compared 
to riparian vegetation elsewhere. Further away from 
the creeks and rivers, the overstorey vegetation in the 
Victoria catchment becomes sparser. 
• Groundwater-dependent ecosystems occur across many 
parts of the Victoria catchment and have different forms, 
including aquatic, terrestrial and subterranean habitats. 
Aquatic groundwater-dependent ecosystems contain 
springs and river sections that hold water throughout 
most dry seasons. 
• Groundwater discharge may be critical for maintaining 
some vegetation condition, such as the habitats of 
monsoon vine forest located within the Bradshaw 
Field Training Area DIWA site. Subterranean aquatic 
ecosystems in the Victoria catchment include known 
sinkholes associated with the Montejinni Limestone, 
which are mapped along the south-eastern edge of the 
Victoria catchment. The connection of these sinkholes 
to underlying groundwater systems is unknown.




• The mouth and estuary of the Victoria River, Queens 
Channel, is up to 25 km wide and includes extensive 
mudflats and mangrove stands. The mangrove 
communities along the estuary are recognised as being 
of high structural value, but low in species richness with 
about ten species recorded. The dominant mangrove 
species in the catchment is Avicennia marina, which is 
largely confined to the estuary. 


The Victoria catchment supports listed 
and threatened species and many lesser-
known plants and animals that are also of 
great importance.

• The Commonwealth’s Protected Matters Search 
Tool includes 45 plant and animal species listed 
as Threatened for the Victoria catchment, four of 
which are listed as Critically Endangered under 
the Commonwealth Environment Protection and 
Biodiversity Conservation Act 1999 (EPBC Act): the 
nabarlek rock wallaby (Petrogale concinna concinna), 
Rosewood keeled snail (Ordtrachia septentrionalis), 
curlew sandpiper (Calidris ferruginea) and eastern 
curlew (Numenius madagascariensis). Also listed are 
49 migratory bird species.
• The aquatic habitats of the Victoria catchment support 
some of northern Australia’s most archetypical and 
important wildlife species. Sawfish, marine turtles, the 
Australian snubfin dolphin and river sharks inhabit the 
estuaries of the Victoria River and the coastal waters of 
the Joseph Bonaparte Gulf. 
• Recent surveys demonstrate the river is a globally 
significant stronghold for three endangered species: 
freshwater sawfish (Pristis pristis; listed as Vulnerable 
under the EPBC Act and Critically Endangered on the 
International Union for Conservation of Nature (IUCN) 
Red List of Threatened Species); speartooth shark 
(Glyphis glyphis; Critically Endangered, EPBC Act and 
IUCN Red List); and northern river shark (Glyphis garricki; 
Endangered, EPBC Act and IUCN Red List).
• Healthy floodplain ecosystems and free-flowing rivers 
mean that very few freshwater fishes in the study area 
are threatened with extinction.
• Bird species including the red knot (Calidris canutus; 
Endangered, EPBC Act) and the critically endangered 
eastern curlew and curlew sandpiper use habitats 
such as the Legune coastal floodplain as an important 
stopover habitat.


Riparian vegetation along the West Baines River in the Victoria catchment. Relative to the fraction of the 
landscape that it occupies riparian vegetation plays a disproportionate role in regulating stream water quality.



Indigenous values, rights 
and development goals

Indigenous Peoples constitute almost 75% of the 
Victoria catchment population. 

• Traditional Owners have Aboriginal freehold land 
ownership and hold native title and cultural heritage 
rights. They control, or are the custodians of, significant 
natural and cultural resources, including land, water, 
coastline and sea.
• Aboriginal freehold title, held under the Commonwealth 
Aboriginal Land Rights (Northern Territory) Act 1976 (ALRA) 
makes up 31% of the Victoria catchment. Over half of this 
holding is the jointly managed Judbarra National Park, 
for which a 99-year lease is held by the NT Government. 
ALRA land cannot be sold and is granted to Aboriginal 
Land Trusts, which have the power to grant an interest 
over the land. 
• Native title exists in parts of the native title 
determination areas that cover an additional 34% of 
the catchment.
• Water-dependent fishing and hunting have key health 
and economic roles for Indigenous Peoples in the 
Victoria catchment. The river supports food security, 
good nutrition, gathering and knowledge-sharing and 
is crucial to the songlines that connect geographical and 
cultural relationships.
• The history of pre-colonial and colonial patterns of land 
and natural resource use in the Victoria catchment is 
important to understanding present circumstances. 
This history has shaped residential patterns, and it also 
informs responses by the Indigenous Peoples to future 
development possibilities. 


From an Indigenous perspective, ancestral 
powers are still present in the landscape and 
intimately connect Peoples, Country and culture. 

• Ancestral powers must be considered in any action that 
takes place on Country. 
• Riverine and aquatic areas are known to be strongly 
correlated with cultural heritage sites.
• Some current cultural heritage considerations restrict 
Indigenous capacity to respond to development 
proposals because some knowledge is culturally sensitive 
and cannot be shared with those who do not have the 
cultural right and authority to know.


Catchment-wide deliberative processes will 
be vital to ensuring that Indigenous water 
rights and interests are included in future 
water‑dependent development and planning. 

• Effective Traditional Owner corporate and wider 
regional governance processes underpin successful 
catchment‑scale processes and support Traditional 
Owner management of external pressure for 
development. Indigenous participants in the Assessment 
identified the Assessment itself as a manifestation of 
that pressure.
• Indigenous Peoples in the Victoria catchment have not 
had substantial exposure to water planning or catchment 
management processes. There is a clear need to build 
this capability before asking people to make decisions 
about water-dependent development. 
• If water resources were to be developed, participants in 
the Assessment would generally prefer flood harvesting, 
which would fill offstream storages. There was 
widespread resistance to large instream dams in 
major rivers.
• Groundwater is currently used for a number of 
communities, but water quality concerns exist. 
• Indigenous Peoples have business and water 
development objectives designed to create opportunities 
for existing residential populations and to improve 
nutrition and safe remote-community water supply. 
• Indigenous Peoples want to be owners, partners, 
investors and stakeholders in any future development. 
This reflects their status as the longest-term residents 
with deep inter-generational ties to the catchment.


Bowerbird bower in the Victoria catchment.



Indigenous property rights, interests and Indigenous Protected Areas in the Victoria catchment.



Opportunities for agriculture 
and aquaculture

There is very little rainfed or irrigated cropping 
underway in the Victoria catchment, although 
several pastoral stations have grown a limited 
amount of forage to provide higher‑quality feed 
to their cattle. 

Although an abundance of soil is suitable for 
irrigated agriculture in the Victoria catchment, 
the lack of coincidence of suitable soil, water 
and favourable topography considerably 
constrains the area that could potentially 
be irrigated.

• Up to approximately 3 million ha of soils in the Victoria 
catchment are classified as moderately suitable with 
considerable limitations (Class 3) or better (Class 1 or 
Class 2) for irrigated agriculture, depending on the crop 
and irrigation method chosen.
• Class 3 soils have considerable limitations that lower 
production potential or require more careful management 
than more suitable soils, such as Class 2 soils.
– Soil classes (1 to 5) are described in the map legend 
below. As explained in the caption, the area figures 
presented in the text are an upper limit.



• Just over 3 million ha of soils in the Victoria catchment 
are rated as Class 3 or better for trickle-irrigated 
intensive crops, such as melons, in the dry season. 
Most of this area is Class 2 land. 
• About 2.9 million ha of the Victoria catchment are rated 
as Class 3 or better for annual hay, forage or silage 
crops such as forage sorghum using spray irrigation in 
the dry season; over 2 million ha of that area is Class 2. 
However, under furrow irrigation, only 625,000 ha are 
Class 3 or better in the dry season and only 425,000 ha in 
the wet season, highlighting the poor drainage (and thus 
waterlogging) of the heavier soils.


Modelled land suitability class for (a) intensive horticulture (such as melons) using trickle irrigation in the dry season and (b) annual 
grasses for hay, forage or silage (such as sorghum) using furrow irrigation in the dry season. The inset for each map shows the 
reliability of this classification.

This map does not consider risk of flooding, secondary salinisation or water availability. The area estimates given in the text are an upper 
starting point derived from assessing soil, landscape and climate factors within the whole catchment. The area actually available for irrigation 
will be less after considerations relating to land tenure, land ownership and use, community acceptance, flooding risk, availability and 
proximity of water for irrigation and other factors are taken into account.



Young cattle being finished on feed before sale.



The soils in different parts of the study area are 
starkly different.

• For the purposes of evaluating the opportunities and 
risks of irrigation development, the Victoria catchment 
can be conceptualised as two river systems: the smaller 
Baines River subcatchment which includes the West and 
East Baines rivers (15,100 km2), and joins the Victoria 
River towards its estuary, and the larger Victoria River 
(55,300 km2) upstream of this junction.
• Within the entire Baines catchment there are 
approximately 103,000 ha of contiguous clay soils 
suitable for broadacre irrigation, with considerable 
limitations, under surface irrigation. The cracking clay 
soils on the broad alluvial plains of the West Baines 
River upstream of the Victoria Highway offer the 
greatest potential for broadacre irrigation in the Victoria 
catchment. Further downstream, the suitability of soil for 
irrigated agriculture becomes increasingly marginal due 
to increasing seasonal wetness (leading to waterlogging 
and trafficability issues) and flooding, so enterprises 
would become increasingly less commercially viable 
and/or would operate with higher risk.
• Taking into consideration the need to site offstream 
storages on heavier clay soils, approximately 22,000 ha 
of contiguous alluvial clay and well-drained sandy 
and loamy soils within 5 km of the Wickham and 
Victoria rivers (allowing a 100 m riparian buffer) could 
potentially be developed for dry-season irrigation. 
However, the complexity of the landscape along these 
rivers, which includes sandy levee soils and increasing 
elevation away from the Wickham and Victoria 
rivers, means the location and configuration of water 
harvesting operations would need to be carefully 
planned to be commercially viable. Once the better 
opportunities were developed, additional developments 
would become increasingly less viable.
• North-east of Top Springs there are approximately 
52,000 ha of clay soils potentially suitable, with 
considerable limitations, for broadacre irrigated 
agriculture under dry-season surface irrigation. 
There are also 62,000 ha of well-drained sandy and 
loamy soils potentially suitable, with considerable 
limitations, for irrigated annual and perennial 
horticultural crops under dry-season trickle irrigation.
• Along the very remote eastern and southern margins of 
the Victoria catchment are 695,000 ha of well-drained 
sandy and loamy soils that are potentially suitable, with 
considerable limitations, for irrigated annual and perennial 
horticultural crops under dry-season trickle irrigation.
• When of sufficient depth and water-holding capacity, the 
loamy soils of the Sturt Plateau on the eastern margins, 
as well as the sandy and loamy soils in the south-east 
and south-west of the Victoria catchment, are suitable 
for a broad range of spray- and trickle-irrigated crops 
planted in both wet and dry seasons. 




The cracking clay soils on the broad treeless alluvial plains of the West Baines River upstream of the 
Victoria Highway offer the greatest potential for broadacre irrigation in the Victoria catchment.

Irrigation enables higher yields 
and more flexible and reliable 
production than rainfed crops

• Many annual crops can be grown at most times of 
the year with irrigation in the Victoria catchment. 
Irrigation provides increased yields and flexibility in 
sowing date.
• Sowing dates must be selected to balance the need 
for the best growing environment (optimising solar 
radiation and temperature) with water availability, pest 
avoidance, trafficability, crop sequences, supply chain 
requirements, infrastructure requirements, market 
demand, seasonal commodity prices and, in the case of 
genetically modified cotton, planting windows specified 
within the cotton industry.
• Irrigated crops likely to be commercially viable with 
a dry-season planting (late March to August) include 
annual horticulture and cotton. Irrigated crops likely 
to be commercially viable with a wet-season planting 
(December to early March) include cotton, forages 
and peanuts.
• Seasonal irrigation water applied to crops can vary 
enormously with crop type (e.g. due to variations in 
duration of growth, rooting depth), season of growth, 
soil type and rainfall received. For example, wet-season 
and dry-season cotton on a clay soil in a climate similar 
to Top Springs requires about 4.6 ML/ha and 5.7 ML/ha, 
respectively, of irrigation water in at least 50% of years. 
A high-yielding perennial forage such as Rhodes grass on 
a clay soil requires about 24.0 ML/ha each year, averaged 
across a full production cycle.
• Rainfed cropping is theoretically possible in some years, 
but agronomic and market-related constraints mean it is 
most likely to be opportunistic in the Victoria catchment 
based on rainfall received and stored soil water, or it may 
serve as an adjunct to irrigated farming.


How cleared land is managed in the years when 
rainfall is insufficient for rainfed cropping will be 
crucial for sustainable farming operations and 
the industry’s social licence to operate.

Excess rainfall can also constrain crop production 
on some soils.

• The cracking clay soils on the alluvial plains of some 
of the major rivers in the Victoria catchment have high 
to very high water-holding capacity, but much of the 
area is subject to frequent flooding and inadequate soil 
drainage. In some places, small and/or narrow areas 
have a level of landscape complexity that will constrain 
farming practices. 
• High rainfall and possible inundation mean that wet‑season 
cropping on the alluvial clay soils carries considerable 
risk due to potential difficulties with access to paddocks, 
trafficability and waterlogging of immature crops.
• Accumulation of soil salinity due to irrigation in these 
clay soils is currently unknown but must be monitored, 
especially in the imperfectly drained cracking clay soils 
on the lower Baines, Angalarri and Victoria rivers.




Establishing irrigated cropping in a new region 
(i.e. greenfield development) is challenging. It has 
high input costs and high capital requirements 
and requires an experienced skills set.

• For broadacre crops, gross margins of the order of 
$4,000 per hectare per year are required to provide 
a sufficient return on investment where on-farm 
development capital costs are about $20,000/ha. 
Crops likely to achieve such a return include Rhodes 
grass hay and wet‑season cotton, noting that the gross 
margins of hay are highly sensitive to local demand, 
price and the cost of transport.
• Horticultural gross margins would have to be higher than 
broadacre crops, in the order of $7,000 to $11,000 per 
hectare per year, to provide an adequate return on the 
higher capital costs of developing this more intensive 
type of farming (relative to broadacre). Profitability of 
horticulture is extremely sensitive to prices received, 
so the locational advantage of supplying out-of-season 
(winter) produce to southern markets is critical to 
viability. Horticulture will struggle to meet these gross 
margins in the Victoria catchment; perennial fruit trees 
may be more successful, although it will be difficult to 
achieve the higher gross margins required.


Bushfoods are an emerging niche industry 
across northern Australia. However, most 
bushfoods continue to be wild‑harvested 
with very little grown commercially. Limited 
information on commercial bushfood operations 
is publicly available.

Growing more than one crop per year 
may enhance the viability of greenfield 
irrigation development.

• There are proven benefits to sequentially cropping more 
than one crop per year in the same field in northern 
Australia, particularly where additional net revenue 
can be generated from the same initial investment in 
farm development.
• Numerous options for crop sequences could be 
considered, but these would need to be tested and 
adapted to the particular opportunities and constraints 
of the Victoria catchment’s soils and climate. While 
somewhat opportunistic, the most likely sequential 
farming systems on the heavier clays could be those 
combining short-duration crops such as annual 
horticulture (e.g. melons), legumes such as mungbean 
and chickpea, and grass forages.
• Trafficability constraints on the alluvial clay soils will 
limit the options for sequential cropping systems 
because of the tight time frames to grow and harvest 
the first crop before preparing the land and planting 
the next crop. The well-drained loamy soils pose fewer 
constraints for scheduling sowing times and the farm 
operations required for sequencing two crops in the 
same field each year. Even so, sequential cropping 
systems that include cotton may not be possible in all 
years due to trafficability constraints; that is, it may not 
be possible to plant cotton early enough in the season 
for another crop to follow.
• Tight scheduling requirements mean that even viable 
crop sequences may be opportunistic. The challenges 
in developing locally appropriate sequential cropping 
systems, and the management practices and skills to 
support them, should not be under estimated.




Irrigated cropping has the potential to produce 
off-site environmental impacts, although these 
can be mitigated by good management and 
new technology.

• The pesticide and fertiliser application rates required 
to sustain crop growth in these climates vary widely 
among crop types. Selecting crops and production 
systems that minimise the requirement for pesticides and 
fertilisers can simultaneously reduce costs and negative 
environmental impacts.
• Refining application rates of fertiliser to better match 
crop requirements, using controlled-release fertilisers 
and improving irrigation management are effective ways 
to minimise nutrient additions to waterways and, hence, 
the risk of harmful microalgae blooms. 
• Adherence to well-established best management 
practices can significantly reduce erosion where 
intense rainfall and slope would otherwise promote 
risk. This would also serve to decrease the risk of 
herbicides, pesticides and excess nitrogen entering 
the natural environment.
• More than 99% of the cotton grown in Australia is 
genetically modified. The genetic modifications have 
allowed the cotton industry to substantially reduce 
insecticide (by greater than 85%) and herbicide 
application to much lower levels than previously used. 
In addition to reducing the likelihood and severity 
of off-site impacts, genetically modified crops offer 
health benefits to farm workers who handle fewer 
chemicals. This technology has considerable relevance to 
northern Australia. 


Irrigated forages can increase the number of 
cattle sold and the income of cattle enterprises. 
However, the increased income is usually offset 
by the high initial capital costs and ongoing 
costs of irrigating a forage crop.

• The dominant beef production system in the Victoria 
catchment is breeding cattle, rather than fattening them 
for slaughter, with the major market being the sale of 
young animals for live export.
• While native pastures are generally well adapted 
to harsh environments, they impose constraints on 
beef production through their low productivity and 
digestibility and their declining quality through the 
dry season. Growing irrigated forages and hay would 
allow higher-quality feed to be fed to specific classes of 
livestock to achieve higher production and/or different 
markets. These species could include perennial grasses, 
forage crops and legumes.
• Grazing of irrigated forages by young cattle, or feeding 
them hay, decreases the time they take to reach sale 
weight and, in particular, increases their daily weight 
gain through the dry season.
• While ostensibly simple, there are many unknowns 
regarding the best way to implement a system whereby 
irrigated forages and hay are grown on-farm to augment 
an existing cattle production system.
• Growing forages or hay to feed young cattle for the 
export market was not financially viable in the modelled 
scenarios tested. While beef production and total 
income increased, gross margins were less than for 
baseline cattle operations. 


The Wickham River downstream of Yarralin. Adjacent to the river are red loam and sandy levee soils potentially suitable for 
irrigated horticulture. On the break of slope these soils are susceptible to erosion, as can be seen on the margins of the river banks. 
Also pictured are contiguous areas of naturally treeless alluvial clay soils that are potentially suitable for irrigated broadacre crops.



Pond-based black tiger prawns 
or barramundi (in saltwater) or 
redclaw crayfish (in fresh water) 
offer potentially high returns

Along the very remote coastal margins of the study 
area, about 93,000 ha of land is suitable for prawn 
and barramundi aquaculture, using earthen ponds.

• Prawn and barramundi aquaculture elsewhere in 
northern Australia have proven land-based production 
practices and well‑established markets for harvested 
products. These are not fully established for other 
aquaculture species being trialled in northern Australia.
• Prawns could potentially be farmed in either extensive 
(low-density, low-input) or intensive (higher-density, 
higher-input) pond-based systems. Land-based farming 
of barramundi would likely be intensive. 
• The most suitable areas of land for pond-based marine 
aquaculture systems are restricted to the areas of the 
catchment under tidal influence and the river margins 
where cracking clay and seasonally or permanently wet 
soils dominate. 
• Annual operating costs for intensive aquaculture are so 
high that they can exceed the initial cost of developing 
the enterprise. Operational efficiency is, therefore, 
the most important consideration for new enterprises, 
particularly the production efficiency in converting feed 
to saleable product.


Surface water storage potential

Indigenous customary, residential and economic 
sites are usually concentrated along major 
watercourses and drainage lines. Consequently, 
potential instream dams are more likely to have 
an impact on areas of high cultural significance 
than are most other infrastructure developments 
of comparable size. 

• Complex changes in habitat resulting from inundation 
could create new habitat to benefit some species, 
while other species could experience a negative impact 
through loss of habitat.


In the Victoria catchment, the potential for 
irrigated agriculture based on large instream 
dams is low relative to some other large 
catchments in northern Australia. This is due to 
the lack of coincidence between locations that 
are potentially suitable for large instream dams 
and the larger contiguous areas of soil suitable 
for irrigated agriculture.

• Due to the limited areas of contiguous soil suitable for 
irrigated agriculture and favourable topography for 
reticulation infrastructure, the more feasible potential 
dam sites are on smaller headwater catchments. 
• Considering proximity to the Victoria Highway (~85 km) 
and the service centre of Kununurra (~220 km), 
a hypothetical large instream dam on the upper West 
Baines catchment could yield 64 GL in 85% of years and 
cost $396 million (−20% to +50%) to construct, assuming 
favourable geological conditions. This equates to a 
unit capital cost of $6188/ML. Due to the favourable 
topography at this location, a reticulation scheme with 
a nominal 3780 ha under irrigation is estimated to cost 
an additional $12.67 million or $3350/ha of irrigated 
area (excluding farm development and infrastructure). 
This is broadly representative of the cost of the better 
opportunities for large-scale water storage and irrigated 
agriculture in the Victoria catchment.
• The Victoria River Roadhouse is about 200 km from 
Katherine, the nearest point on the Darwin–Katherine 
Interconnected System (DKIS) regulated power network. 
This distance limits opportunities for hydro-electric 
power generation in the Victoria catchment. Even if 
transmission lines were to connect the Victoria catchment 
to the DKIS, the DKIS is electrically isolated from other 
grids in Australia, so any large-scale electrical generation 
infrastructure in the Victoria catchment would still be 
disconnected from the National Electricity Market.
• An instream dam upstream of Kalkarindji, designed 
and managed specifically for flood mitigation, could 
potentially reduce flood peak magnitude downstream. 
For the ten largest modelled rainfall events, the dam 
reduced peak flow by around 50% at Kalkarindji and less 
than 20% at Nitjpurru (Pigeon Hole). 




• Suitably sited large farm-scale gully dams are a 
relatively cost-effective method of supplying water. 
The topography of the Victoria catchment is highly 
suitable for large farm-scale gully dams throughout 
much of the catchment. The major limitation is that the 
soil is rocky and shallow, so access would be required 
to a nearby clay borrow pit to provide material for the 
cut-off trench and dam wall core zone. Potential gully 
dams requiring material from elsewhere will be less 
economically viable.


The alluvial clay soils on the West Baines River 
upstream of the Victoria Highway and the 
narrow river frontages along the Victoria and 
Wickham rivers offer some opportunities for 
water harvesting.

• Although the upper West Baines River has more soil 
suitable for irrigated agriculture than water, some of 
the suitable soils would be needed for water storage. 
Along the Victoria River and its other major tributaries, 
the scale of potential surface water development is 
constrained by soil suitable for irrigated agriculture 
rather than by water.
• Along the Victoria River, loamy levees mean that 
soils suitable for ringtanks can be up to 1 km away. 
This distance and the increasing elevation away from the 
river considerably increase the capital and operational 
costs of water harvesting enterprises by increasing the 
cost of piping and pumping water.
• It is physically possible (based on coincidence of suitable 
soil, water and topography) to extract 690 GL and 
irrigate 50,000 ha of broadacre crops on the clay alluvial 
soil and sandy and loamy soils during the dry season 
in 75% of years. This would be achieved by pumping or 
diverting water from the Baines River (~28,000 ha with 
area limited by water) and the Victoria River and its other 
major tributaries (~22,000 ha with area limited by soil) 
and storing it in offstream storages such as ringtanks. 
This extraction results in a modelled reduction in the 
mean and median annual discharges from the Victoria 
catchment of about 9% and 12%, respectively.
• Using the Northern Territory Government’s recently 
released surface water take policy, the annual 
consumptive pool available for the entire Victoria River 
catchment, including the Baines River, is approximately 
130 GL (2% of median annual discharge), when using the 
1890–2022 modelled period. If this period is reduced to 
1970–2022, the annual consumptive pool increases to 
approximately 200 GL.


With more than 20,000 ha of land under irrigation the Ord River Irrigation Area is the 
largest irrigation scheme in northern Australia west of the Great Dividing Range.



Groundwater in the Victoria 
catchment offers year‑round 
niche opportunities that are 
locationally distinct from surface 
water development opportunities

• Groundwater is already widely used in parts of the Victoria 
catchment for providing drinking water for livestock but 
also for community water supplies and domestic use.


The most productive groundwater systems in 
the Victoria catchment are the regional-scale 
Cambrian Limestone Aquifer (CLA) along the 
very remote eastern margins of the catchment 
and the local- to intermediate-scale Proterozoic 
dolostone aquifers (PDAs) in the centre and south 
of the catchment.

• The CLA is a large regional-scale groundwater system 
that extends over 1500 km from north-west Queensland 
to north-west NT. It occurs across three sedimentary 
basins: the Georgina, Wiso and Daly geological basins. 
• Currently no licensed groundwater entitlements from 
the CLA exist in the Victoria catchment. The nearest 
licensed entitlements from the CLA are about 150 km to 
the north-east of the Victoria catchment and occur in the 
proposed Flora Tindall Water Allocation Plan area in the 
Daly catchment.
• These three licensed entitlements are assigned for 
agricultural use and total 7.4 GL/year. However, actual 
groundwater use is currently less.
• There is currently very little development of groundwater 
from the PDAs other than for stock and domestic 
bores and the community water supply at Timber 
Creek. No water allocation plan currently exists for 
the Victoria catchment.
• Water in both the CLA and PDAs is mostly fresh (total 
dissolved solids <1000 mg/L) with chemistry reflective 
of the carbonate rocks within which they are hosted. 
This results in the water having a high hardness, which 
may result in scaling on water infrastructure.
• Water discharging from the CLA and PDAs supports 
numerous ecologically and culturally important springs. 
Spring flows depend on short-term rainfall patterns and 
are known to gradually decrease in discharge as the dry 
season progresses with some springs not being able to 
maintain permanent flows.
• Any extraction of groundwater for consumptive 
purposes will result in a corresponding reduction in 
discharge to rivers, springs and vegetation.
• The time lag between groundwater extraction and the 
corresponding change in the expression of groundwater 
where it naturally discharges may be many decades in 
intermediate-scale groundwater systems and longer in 
regional systems. This presents management challenges 
but also adaptive management opportunities.


With appropriately sited groundwater borefields 
along the eastern and southern margins of the 
Victoria catchment, an estimated 10 GL/year 
could potentially be extracted from the CLA to the 
south of Top Springs. This depends on community 
and government acceptance of impacts to 
groundwater-dependent ecosystems and existing 
stock and domestic groundwater users. 

• This volume of groundwater could potentially enable up 
to an additional 1350 ha (0.015% of the catchment) of 
irrigated agriculture depending upon the percentage mix 
of broadacre crops, horticulture and hay production.
• The CLA discharges naturally via a combination of 
intermittent lateral outflow to streams where they are 
incised into the aquifer outcrop (Armstrong River and 
Bullock, Cattle and Montejinni creeks) and perennial 
localised spring discharge (Old Top, Lonely, Palm 
and Horse springs). Where groundwater in the CLA 
approaches the ground surface, it is also evaporated 
from the soil and riparian and spring-fed vegetation.




• Due to the relatively short groundwater flow paths 
(~20 km) between hypothetical groundwater extractions 
and groundwater discharge zones, a hypothetical 
groundwater extraction of 9 to 12 GL/year from the 
CLA would result in a 13% to 16% modelled reduction in 
groundwater discharge to spring complexes near Top 
Springs at about 2060. 
• Modelled reduction in groundwater levels ranges 
from about 15 m at the centre of the hypothetical 
developments to 1 m up to 20 km away by about 2060. 
Due to the long distances and long timescales over 
which groundwater lateral flow occurs, modelled 
impacts to licensed entitlements in the proposed Flora 
Tindall Water Allocation Plan or the proposed Mataranka 
Water Allocation Plan would be negligible. 
• Under a projected dry future climate that assumes a 10% 
reduction in rainfall across the entire CLA (rather than 
just within the Victoria catchment) and no future 
hypothetical groundwater development, the modelled 
reduction in groundwater recharge to the CLA near 
Top Springs is 32%, and the modelled reduction in 
groundwater discharge to the nearby spring complexes 
is 33%. 
• The modelled changes in the water balance under a 
projected drier future climate are larger than for the 
modelled future hypothetical groundwater development. 
This highlights the sensitivity of groundwater storage in 
and discharge from the CLA near Top Springs to natural 
variations in climate.


There may be potential to extract up to 
20 GL/year from the PDAs in the centre and 
south of the Victoria catchment. 

• Very little data are available for these aquifers and 
opportunities will be localised. 
• Outcropping and subcropping units of dolostone 
aquifers are scattered across the centre and southern 
parts of the Victoria catchment where they are 
actively recharged. They tend to steeply dip below the 
subsurface, but in many cases nearby units are likely to 
be hydraulically connected. Elsewhere, the aquifers are 
confined by overlying basalt, sandstone and shale.
• The PDAs discharge naturally via a combination of 
intermittent lateral outflow to streams where they are 
incised into the aquifer outcrops (East Baines River 
and Crawford, Giles and Middle creeks) and perennial 
localised discharge at discrete springs in contact with 
low-permeability basalt, sandstone and shale on the 
margin of the outcropping areas (Bulls Head, Kidman, 
Crawford, Depot, Farquharson and Wickham springs).
• Despite outcropping and subcropping dolostone aquifers 
covering approximately 7000 km2 of the Victoria 
catchment, they only coincide with contiguous areas of 
soils suitable for irrigated agriculture at two locations. 
• The largest area is along the south-west margin of the 
catchment, where 85,000 ha of loamy and sandy soils 
suitable for irrigated horticulture overlay a PDA and is 
traversed by the unsealed Buntine Highway. Elsewhere 
15,000 ha of clay soils suitable for broadacre irrigated 
cropping along Battle Creek, a minor tributary of the 
Victoria River, overlay part of a PDA.


There are limited opportunities for managed 
aquifer recharge in the Victoria catchment.

• Areas of the Victoria catchment with permeable 
soils and favourable slope and storage capacity for 
managed aquifer recharge (e.g. Sturt Plateau along 
the eastern margin of the Victoria catchment) have 
rivers that are highly intermittent, so there is no 
reliable and cost‑effective source of water for managed 
aquifer recharge.


Clear carbonate spring waters of Kidman Creek on the Victoria River Research Station.



Changes in volumes and 
timing of river flows have 
ecological impacts

• Although irrigated agriculture may occupy only a 
small percentage of the landscape, relatively small 
areas of irrigation can use large quantities of water, 
and the resulting changes in the flow regime can have 
profound effects on flow-dependent flora and fauna 
and their habitats. 
• Changes in river flow may extend considerable distances 
downstream and onto the floodplain, including into 
the marine environment and their impacts can be 
exacerbated by other changes, including changes to 
connectivity, water quality and invasive species. 


The magnitude and spatial extent of 
ecological impacts arising from water resource 
development are highly dependent on the type 
of development, location, extraction volume 
and mitigation measures implemented.

• Ecological impacts, inferred here by calculating change 
in ecological flow dependency for a range of fresh 
water‑dependent ecological assets, increase non-linearly 
with increasing scale of surface water development 
(i.e. large instream dams and water harvesting). 
• At equivalent levels of water resource development 
(i.e. in terms of volume of water extracted), and without 
significant mitigation measures, instream dams have 
a larger mean impact to surface-flow-dependent 
ecology than water harvesting, averaged across the 
Victoria catchment. 
• Impacts from water harvesting tend to accumulate 
downstream, so ecological assets found near the bottom of 
the catchment experienced the greatest average catchment 
impact. Cryptic waders, threadfin, prawns and floodplain 
wetlands are among the ecological assets most affected 
by flow changes for water harvesting. Catfish, grunter 
and inchannel waterholes, found throughout the study 
area, are the ecological assets least affected. 
• Water harvesting developments extracting 80 to 
690 GL/year of water without any mitigation strategies 
resulted in negligible changes to ecology flow 
dependencies of freshwater assets when averaged across 
the Victoria catchment. Local impacts below points of 
extraction, however, were moderate to major for some 
freshwater assets at the higher extraction volumes 
and moderate for near-shore marine assets at higher 
extraction volumes


Mitigation strategies that protect low flows 
and first flows of a wet season are successful in 
reducing impacts to ecological assets. These can 
be particularly effective if implemented for 
water harvesting developments.

• At equivalent volumes of water extraction, imposing an 
end-of-system (EOS) annual flow requirement, where 
water harvesting can only commence after a specified 
volume of water has flowed past the EOS and into 
the Joseph Bonaparte Gulf, is an effective mitigation 
measure for water harvesting. However, because the 
early wet-season streamflow in the Baines River is 
only moderately correlated with the early wet-season 
streamflow in the Victoria River, assigning an EOS annual 
flow requirement for each river may result in more 
targeted ecological outcomes than a single EOS annual 
flow requirement for the entire catchment.
• For EOS annual flow requirements greater than 
200 GL, additional mitigation measures (e.g. increasing 
pump‑start capacity or decreasing pump rate) have 
little additional modelled ecological benefit for 
water harvesting.
• Relative to catchments with large dry-season flows 
maintained by groundwater discharge from a 
regional‑scale groundwater system (e.g. the Roper 
catchment), increasing pump-start thresholds in the 
Victoria catchment to above 400 ML/day only results in 
marginal improvements to ecological flow dependencies. 
• A dry future climate has the potential to have a larger 
mean impact on ecological flow dependencies across the 
Victoria catchment than the largest physically plausible 
water resource development scenario. However, the 
perturbations to flow arising from a combined drier 
future climate and water resource development result in 
greater impacts on ecology flow dependency than either 
factor on their own.


For instream dams, location matters, and there 
is potential for risks of large local impacts. 
Improved outcomes are associated with 
maintaining attributes of the natural flow regime.

• Potential dams located in small headwater catchments 
may result in a extreme change in the ecological flow 
dependency immediately downstream of the dam. 




However, impacts reduce downstream with the 
accumulation of additional tributary flows, so when 
averaged over the entire catchment or measured at the 
EOS, the change in ecological flow dependency is minor. 
• Providing transparent flows (flows allowed to ‘pass 
through’ the dam for ecological purposes) improves 
flow regimes for ecology by reducing the mean yield of 
potential dams. Mean outcomes for fish assets can be 
improved from minor to negligible, and for waterbirds 
from moderate to minor, at catchment scales.


But it’s not just flow, other impacts and 
considerations are also important.

• At catchment scales, the direct impacts of irrigated 
agriculture on the terrestrial environment are typically 
small. However, indirect impacts such as weeds, pests 
and landscape fragmentation may be considerable, 
particularly to riparian zones.
• Loss of connectivity associated with new instream 
structures and changes in low flows may limit movement 
patterns of many species within the catchment. This may 
include some road causeways and low structures within 
a river to divert water or create pumping pools to enable 
water harvesting.


Inefficient farm practices, poorly managed 
irrigation outflows and uncontrolled runoff from 
irrigation areas close to drainage lines could 
have a larger impact on ecological condition 
than likely changes in river flow patterns and 
volume in the Victoria catchment.

• Nitrogen, phosphorus, and potassium are the three 
nutrients used primarily in agricultural fertilisers. 
Irrigation outflows and tailwater run-off from irrigation 
events can be high in these nutrients as well as 
pesticides, herbicides and total dissolved solids.
• If best-practice is not followed, the concentrations of 
these contaminants can be elevated in receiving surface 
and groundwater bodies. However, the extent to which 
irrigated agriculture impacts the quality of receiving 
waters is highly variable and depends on a wide range 
of factors including crop type, farm management and 
mitigation measures, type and scale of development, 
water application method, proximity to drainage lines 
and environmental factors such as climate, soil type, 
topography, hydrogeochemistry and susceptibility of 
irrigated land to flooding. 
• Studies in parts of Queensland with a seasonal hydrology 
have found that first flow events following irrigation or 
rainfall play a critical role in determining water quality. 
Studies have shown that pesticide concentrations in 
furrow irrigation runoff are highest following initial 
irrigation events but decrease in subsequent events.
• When pesticide application rates are managed well and 
irrigation schedules are aligned with crop growth stages, 
the concentration of pesticides in receiving waters are 
typically low, studies in the Ord River Irrigation Area 
have found.
• Vegetated areas can intercept agricultural run-off, 
reducing pesticide concentrations in surface waters 
approximately three times more than in areas of bare 
soil. This highlights the importance of maintaining a 
wide riparian buffer zone.
• Water quality issues will be most significant closest to 
the source, because of dilution and naturally occurring 
processes by which aquatic systems can partially 
process contaminants and regulate water quality, such 
as denitrification in the case of nitrogen and microbial 
degradation and ultraviolet photolysis in the case of 
pesticides. There are no equivalent natural processes 
for reducing phosphorus.


In the highly seasonal climate of the Victoria catchment, waterholes provide important ecological refugia during the dry season.



Commercial viability and 
other considerations

The economic value of irrigated agriculture 
in the Victoria catchment has the potential to 
increase substantially from a very low base.

• The total annual gross value of agricultural production in 
the Victoria catchment in 2020–21 was $110 million, all of 
which came from beef cattle production. 
• About 29% of all jobs in the Victoria catchment are 
associated with the grazing industry.


Large public dams would be marginal in the 
Victoria catchment, but suitably sited on-farm 
water sources could provide good prospects for 
viable new irrigated enterprises.

• Large dams could be marginally viable if public investors 
accepted a 3% discount rate or partial contributions to 
water infrastructure costs similar to established irrigation 
schemes in other parts of Australia.
• On-farm water sources provide better prospects 
and, where sufficiently cheap water development 
opportunities can be found, could likely support viable 
broadacre farms and horticulture where development 
costs were low.
• Proponents of large infrastructure projects have a 
systematic tendency to substantially under estimate 
development costs and risks and to over estimate 
the scale and rate at which benefits will be achieved. 
This Assessment provides information on realistic 
unit costs and demand trajectories to allow potential 
irrigation developments to be benchmarked and 
assessed on a like-for-like basis.
• The viability of irrigated developments would be 
determined by: (i) markets and supply chains that 
can provide a sufficient price, scale and reliability of 
demand, (ii) farmers’ skills in managing the operational 
and financial complexity of adapting crop mixes and 
production systems suited to Victoria catchment 
environments, (iii) the nature of water resources in terms 
of the volume and reliability of supply relative to optimal 
planting windows, (iv) the nature of the soil resources 
and their proximity to supply chains, and (v) the costs 
needed to develop those resources and grow crops 
compared with alternative locations.


It is prudent to stage developments to limit 
negative economic impact and to allow 
small‑scale trialling on new farms.

• Farm productivity is subject to a range of risks, and 
setbacks that occur early have the greatest effect 
on a development’s viability. A period of initial 
underperformance must be anticipated for establishing 
greenfield farming in a new location, and this must be 
planned for.
• There is a strong incentive to start any new irrigation 
development with well-established and understood 
crops, farming systems and technologies, and to 
incorporate lessons from past experiences of agricultural 
development in northern Australia. 
• The Victoria catchment, unlike most northern Australian 
catchments, has the benefit of being close to the Ord 
River Irrigation Area (the Ord). Many of the more 
productive clay soils in the Victoria catchment are 
similar to those of the Ord, so experiences from the 
Ord will have some level of transferability to parts 
of the Victoria catchment. The recently announced 
67,500 ha Keep Plains Agricultural Development adjacent 
to the Ord River Irrigation Area would also provide 
experiential learning for any new development in the 
Victoria catchment.
• Staging allows ‘learning by doing’ at a small scale, where 
risks can be contained while testing initial assumptions 
of costs and benefits and while farming systems adapt to 
unforeseen challenges in local conditions.


Irrigated agriculture has a greater potential than 
rainfed production to generate economic and 
community activity.

• Studies in the southern Murray–Darling Basin have 
shown that irrigation generates a level of economic 
and community activity that is three to five times 
higher than would be generated by rainfed production. 
Irrigated developments can unlock the economies of 
scale for supply chains and support services that allow 
rainfed farming to establish more easily around the 
irrigated core.




• A large proportion of increased economic activity 
during the construction phase of potential 
irrigation developments in the Victoria catchment 
would be expected to leak outside the study area. 
Assuming $250 million in capital costs, which could 
potentially enable 10,000 ha of irrigated agriculture 
(~20 new farm-scale developments with on-farm water 
sources), the total regional economic activity within the 
Victoria catchment associated with the construction 
phase would be approximately $180 million (assuming 
65% leakage out of the study area). Additional benefits 
would flow to other regions, including Kununurra, 
Katherine, Darwin and potentially some areas 
outside the NT.
• The total annual increased economic activity (direct and 
indirect) from 10,000 ha of irrigated mixed broadacre 
(65%) and horticulture (35%) agriculture in the Victoria 
catchment could potentially amount to $280 million, 
supporting up to 185 full-time-equivalent jobs.
• Based on economic data for the entire NT, the 
additional income that flows to Indigenous households 
from beef cattle developments would be one-ninth 
of that which flows to non-Indigenous households. 
The additional income that flows to Indigenous 
households from other agricultural developments 
(excluding beef) would be one-seventeenth of that which 
flows to non-Indigenous households. This indicates that, 
if agricultural developments in the Victoria catchment 
are to equally benefit Indigenous and non‑Indigenous 
households, concerted action will need to be taken by 
all stakeholders, including government, industry groups 
and proponents.


Sustainable irrigated development requires 
resolution of diverse stakeholder values 
and interests.

• Establishing and maintaining a social licence to operate 
is a precondition for substantial irrigation development.
• The geographic, institutional, social and economic 
diversity of stakeholders increases the resources required 
to develop a social licence and reduces the size of the 
‘sweet spot’ in which a social licence can be established.
• Key interests and values that stakeholders seek to 
address include the purpose and beneficiaries of 
development, the environmental conditions and 
environmental services that development may alter, and 
the degree to which stakeholders are engaged.


Top Springs is at the intersection of the Buchanan 
and Buntine Highways in the Victoria catchment.



Frequently asked questions

A full set of FAQs can be found at csiro.au/victoriariver/FAQs

The Victoria River Water Resource Assessment 
found some large areas of suitable land and 
some big volumes of water that are potentially 
available for development. Is CSIRO suggesting 
that all this land and water will be developed in 
the near future?

No. The CSIRO work simply shows the upper limit of what 
might be biophysically possible. In practice, the area 
actually available for development would be considerably 
less. Development decisions will be influenced by laws, 
policies and regulations about land tenure, land ownership, 
land use, water management and environmental 
protection, as well as by production costs and market 
demands. In reality, the nature and scale of potential future 
development will depend heavily upon community and 
government values about desirable forms of development 
and the balance of potential benefits and impacts, including 
impacts to communities and water-dependent ecosystems.

Why did CSIRO not consider existing 
regulatory frameworks?

The Assessment is primarily a resource assessment and 
these resources remain relatively static through time. 
In contrast, legislation and regulation, which are tied to 
government and community values, can and do change 
rapidly. By deliberately setting aside most regulatory issues, 
the Assessment is better placed to provide information 
that will be useful over the longest time frame possible. 
Others with policy and regulatory responsibility and/or 
the capacity to directly influence these regimes can then 
overlay legislative and regulatory frameworks at any point 
in time.

Were Indigenous community considerations 
included in this study?

Yes. A key component of the Assessment involved 
research on Indigenous water values, rights, interests 
and development objectives. The primary participants in 
Indigenous consultations were Traditional Owners from the 
study area identified with the assistance of the respective 
land councils and Indigenous community leaders.

What is the relationship between the 
Assessment and water planning undertaken 
by the Northern Territory Government?

The Northern Territory Government is responsible for 
developing policy and implementing and enforcing 
regulation in the NT. The Northern Territory Government 
places considerable importance on using science- and 
evidence-based approaches to inform the development 
of its policy. CSIRO is Australia’s national science agency; 
it undertakes high-quality scientific research to help 
address the nation’s challenges. CSIRO does not develop 
or recommend changes to policy, nor does CSIRO write, 
implement, administer or enforce regulation. The Northern 
Territory Government’s water policy in the Victoria 
catchment in the future may in part be informed by 
scientific studies undertaken as part of the Assessment, 
but it would also be informed by other evidence-based 
approaches as well as government understanding of values 
held by the community. The NT has longstanding policy 
settings in place that intend to protect and place priority 
on river flows, ecological functions and cultural uses above 
other uses.

Did the Assessment propose particular 
development outcomes?

No. The Assessment did not seek to advocate for water 
resource and irrigation development, or assess or enable 
any particular development. Instead, it identified the 
resources that could be deployed in support of potential 
irrigation enterprises and the constraints on those 
resources. It evaluated the feasibility of development 
by examining options ranging from small-scale mosaic 
development to large-scheme-scale development, and it 
considered the overall scale of the opportunities that might 
exist and the risks that may attend those opportunities. 



Did the Assessment seek to establish formal 
positions from Indigenous groups about any 
of the issues raised?

No. The Assessment worked with individuals and small 
groups to provide a representative spectrum of Indigenous 
values and views as a reliable catchment-scale guide. 
However, Indigenous groups and communities may take 
a variety of positions regarding development and its 
impacts. The Assessment does not substitute for formal 
processes required by cultural heritage, environmental 
impact assessment or water planning legislation. The 
Assessment identified key principles, important issues and 
potential pathways to support future planning and for 
formal negotiations with Indigenous groups about their 
development interests.

Is the Victoria catchment different from other 
catchments across northern Australia?

Yes. Northern Australia is not homogeneous, and 
river catchments vary widely. Consequently, so do the 
opportunities and risks of water resource development. 
Local community attitudes are also different in 
different catchments.

Why was the Victoria catchment chosen?

The Assessment was commissioned by the Australian 
Government, and the Victoria catchment was chosen by the 
Australian Government in consultation with the Northern 
Territory Government. 

Did CSIRO look for dam sites in the 
Victoria catchment?

CSIRO undertook a pre-feasibility analysis of the potential 
for water storages, including dams, in the Victoria 
catchment. This information can be used by governments 
and communities to decide if particular sites warrant more-
detailed feasibility studies. The information can also be 
used to independently evaluate the validity of proposals by 
a future proponent. CSIRO does not suggest that any dam 
should be constructed, nor does CSIRO suggest how dams 
could or should be funded.

Has this research been independently reviewed, 
and by whom?

Yes. The research has been peer-reviewed by scientists not 
associated with the research within CSIRO and by external 
technical experts within the university, public and private 
sectors. CSIRO’s role is to provide independent scientific 
advice to inform decision making. CSIRO places great 
importance on the trust placed in the organisation by 
governments and the Australian community.

Who will use the results of the Assessment?

The results of the Assessment can be accessed by 
anyone. They provide a framework that may be used 
by governments, industry, communities, environment 
advocates, Traditional Owners, individual landholders, 
share farmers and developers to inform resource 
planning, management and investment decisions. More 
specifically, the results can inform local development 
needs and aspirations, government and the due diligence 
requirements of private investors. It also provides a trusted 
information base to enable everyone to equally partake 
in any discussion about water and agriculture resource 
development in the Victoria catchment. The Assessment 
does not replace any planning processes, nor does it seek 
to recommend changes to existing plans or planning 
processes.

What is CSIRO’s position on the expansion of 
agricultural development in northern Australia?

It is not CSIRO’s role to advocate specific policy positions or 
development decisions. CSIRO provides science to underpin 
decision making and help evaluate the likely outcomes from 
different policy or management decisions.

Further detail can be accessed in 18 underpinning 
Technical Reports and their summary, the Catchment 
Report, and can be found at csiro.au/victoriariver.

The Victoria catchment is the eastern most extent of the Boab tree in Australia.



Cover: The Victoria River is the longest singularly named river in the NT with permanent water.

Citation

CSIRO (2024) The Victoria River Water Resource Assessment. 
A summary report from the CSIRO Victoria River Water 
Resource Assessment for the National Water Grid. 
CSIRO, Australia.

This is an overview of the following report: Petheram C, 
Philip S, Watson I, Bruce C and Chilcott C (eds) (2024) 
Water resource assessment for the Victoria catchment. 
A report from the CSIRO Victoria River Water Resource 
Assessment for the National Water Grid. CSIRO, Australia.

csiro.au/victoriariver

Copyright

© Commonwealth Scientific and Industrial Research 
Organisation 2024. To the extent permitted by law, all 
rights are reserved and no part of this publication covered 
by copyright may be reproduced or copied in any form or 
by any means except with the written permission of CSIRO.

Important disclaimer

CSIRO advises that the information contained in this 
publication comprises general statements based on 
scientific research. The reader is advised and needs to be 
aware that such information may be incomplete or unable 
to be used in any specific situation. No reliance or actions 
must therefore be made on that information without 
seeking prior expert professional, scientific and technical 
advice. To the extent permitted by law, CSIRO (including 
its employees and consultants) excludes all liability to any 
person for any consequences, including but not limited 
to all losses, damages, costs, expenses and any other 
compensation, arising directly or indirectly from using this 
publication (in part or in whole) and any information or 
material contained in it.

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accessing this document please contact csiro.au/contact.

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Contact

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csiro.au/contact
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Further information
CSIRO Environment 
Chris Chilcott
Deputy Director, Environment
+61 8 8944 8422
chris.chilcott@csiro.au
csiro.au/victoriariver