Case studies

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Case Study Tindall Limestone and Oolloo Dolostone aquifers in northern Australia

The Tindall Limestone and Oolloo Dolostone aquifers are important groundwater stores. The dry-season flow (May–October) for parts of the Daly River system is mostly dominated by input of groundwater from these 2 underlying aquifers. The aquifers are also a primary source of water for human consumption, with more than 80% of local water use being sourced from groundwater.

A key groundwater level of the Tindall Limestone Aquifer is located near Katherine; a key bore for the Oolloo Dolostone Aquifer is located near the junction of the Douglas and Daly rivers.

In 2020, for the second consecutive year, the normal increase in groundwater levels during the wet season in the Tindall Limestone and Oolloo Dolostone aquifers did not occur because of poor wet-season rainfall (Figures 8 and 9). Except for a few minor increases in groundwater levels following rainfall events, levels in both aquifers declined for most of the year. At 30 June 2020, groundwater levels in the Tindall Limestone Aquifer were the lowest in more than 20 years; levels in the Oolloo Dolostone Aquifer were the lowest on record (since 2006) (BOM 2020f).

Figure 8 Groundwater level in Oolloo Dolostone Aquifer, 2014–20
Figure 9 Groundwater level in Tindall Limestone Aquifer, 2014–20

Data are lacking on the volumes of water stored in the aquifers; however, information on the total annual change in aquifer storage is available. In the Daly River aquifers, there have been 7 annual drops in storage during the past 9 financial years, reflecting a sustained period of relatively poor wet-season rainfall in the region (Figure 10). The very large increase in storage in 2011–12 was primarily attributed to well-above-average rainfall over a 2-year period associated with the 2010–12 La Niña event (BOM 2020g).

Figure 10 Total annual change in aquifer volume in the Daly River region at 30 June 2020 compared with the previous 8 years
For more information, go toWater sources
Case Study Cooks River, New South Wales

Ciaron Dunn, Cooks River Alliance

The Cooks River begins as a series of small watercourses near Graf Park in Bankstown and flows for 23 km east towards Botany Bay/Gamay, flowing through some intensely urban and former industrial landscapes. The care and control of the river are complicated: responsibility is shared between 7 local councils (Strathfield, Burwood, Inner-West, Bayside, Georges River, Canterbury Bankstown, Sydney City), the Metropolitan Local Aboriginal Land Council, Sydney Water, the New South Wales Government and industry.

Integrated catchment management (ICM) approaches sustainable resource management from a whole-of-catchment perspective, recognising the interrelationships between freshwater, marine and terrestrial flora and fauna ecosystems. If addressed in an integrated way, catchment management can ensure conservation and sustainable use of biodiversity in conjunction with other objectives. For example, tree planting for groundwater or riparian (streamside) management can contribute to biodiversity conservation.

Management at a catchment level will help reduce the adverse impacts of built living environments and is an important aspect of overall coastal zone management. Nutrients, sediments and other pollutants arising from within catchments have a significant impact on the health of coastal and marine ecosystems.

Another benefit of the ICM approach is the involvement of all elements of the community. ICM is a very effective way of engaging all the community, including those involved in land-use planning, natural resource management, primary production and conservation, in working together to improve the overall management of their local area.

Cooks River Alliance

The Cooks River Alliance has been established to restore, rehabilitate and renew river vitality. To achieve longer-term success, 8 goals across 3 strategic focus areas have been developed. The focuses are:

  • valued partnerships
  • catchment health advocacy
  • community action.

One of the most important partnerships is with Aboriginal people and organisations in the catchment. Two projects have resulted from consistent consultation and active engagement between the alliance and key representatives from local Aboriginal communities: an Aboriginal history along the Cooks River catchment and the Aboriginal Traditional Ecological Knowledge project.

Other outcomes include the renaming of a wetlands site, hosting of a Culture and Country Day, employment of 35 contractors with Aboriginal heritage, recording and exhibition of 12 oral histories from local people and publication of a book. On-ground works have included construction of 7 rain gardens, with water quality monitoring from 2 of them, and completion of a restoration to wetlands at Landing Lights Wetland.

With communities, 3 major events have been coordinated, more than 300 school students have been introduced to water-sensitive urban design, almost 1,500 community members have been introduced to stormwater management challenges, and more than 10,000 bags of rubbish and weeds have been collected. The alliance has also coordinated publication of 3 ecological health report cards for the Cooks River, launched a new website and produced 9 short films in 7 languages to inform communities about the connections between community action on water and stormwater pollution.

An alliance of connected community and Cooks River catchment land managers is continuing to maintain and improve river catchment health.

Health of the river

The ecological health of the Cooks River has been monitored and evaluated for the following indicators: freshwater benthic macroinvertebrates, water quality, riparian vegetation and benthic diatoms. Sampling is based on subcatchments, rather than sites, and the indicators used are common measures used for waterway assessment. Monitoring results allow strategic and targeted on-ground activities to improve the conditions in the catchment.

Across 5 sites within the catchment, moderate to extreme degradation is indicated, especially in riparian zones that display high degrees of weed invasion. Water quality across freshwater areas is described as fair. All sites have elevated nutrients and turbidity, reflected in diatom populations.

Cooks River Catchment Coastal Management Program

Integrated catchment and coastal management is a complex and challenging task, especially in highly developed and urbanised areas like the Cooks River catchment. The Cooks River Catchment Coastal Management Program (CMP) Stage 1 Scoping Study has developed a shared understanding of the Cooks River catchment and coastal management issues and priorities. The study builds on work by councils, the Cooks River Alliance, state agencies and other stakeholders over several decades.

The scoping study is expected to identify an overall purpose, a clear vision statement and accountable objectives for the CMP. A triple-bottom-line approach was used to identify environmental, social and economic values by their relevance to the Cooks River catchment study area, and their local and broader community benefits. The key coastal and management issues to be addressed by the CMP were identified by establishing the main threats to these values.

For more information, go toWater sources
Case Study Filling of Narran Lakes/Dharriwaa

The Narran Lakes/Dharriwaa have long played an important role for Indigenous people. The Narran Lakes have significant Indigenous cultural value, and are the site of many important Indigenous artefacts, including a rock quarry. In the past, these rocks were used to make tools and to trade between tribes, and there is extensive archaeological evidence of a long history of Indigenous use and occupation of the lake system. The lakes were a rich source of food and other resources for Indigenous people, and were an important meeting and trading place for Euhlaroi, Euahlayi, Kamilaroi, Murawarri, Ngemba, Ngiyampaa and Wayilwan people. Further afield, the Barkandji, Bigambul, Kooma and Mandandanji people also have cultural connections with the Kamilaroi and Euhlaroi/Euaylayi (Davies et al. 2020).

The Narran Lakes wetland system is an internationally recognised Ramsar wetland and an important waterbird habitat. Endangered native waterbirds rely on the lakes to breed and survive.

Between 2017 and 2019, long-term rainfall deficiencies developed in the Condamine–Balonne catchment, particularly the Upper Condamine (Figure 22). The 2019 rainfall was the lowest annual rainfall on record for the catchment since 1911. At only 177 mm, it was 50 mm lower than the nearest record set in 1915, and 121 mm lower than the 298 mm received in 2006 at the peak of the millennium drought.

Figure 22 Rainfall deficiencies in the Condamine–Balonne catchment, 2017–19
Map showing that rainfall was very low or lowest on record everywhere in the Condamine–Balonne catchment in 2017–19.

The lack of rain affected soil moisture, water storages, groundwater and river flow, and the human and environmental systems that rely on them. The total volume of water in the major storages in the region fell to 4% in January 2020, the lowest since 2009, with Beardmore water storage at only 2% (Figure 23).

In February 2020, most of the Condamine–Balonne catchment received 25–200 mm of rain. The rain was widespread and delivered through a series of rain bands. The February rain started the rivers flowing and weirs filling. Beardmore water storage went from 2% to 100% in only 8 days and started spilling on 15 February.

Figure 23 Water storage levels in Beardmore water storage (Lake Kajarabie, 86 gigalitre capacity)

The water started to make its way down the system from early February. Flow in the Balonne River peaked north of St George at Weribone at more than 160 gigalitres/day before joining the flow from the Maranoa River and quickly filling Beardmore and Jack Taylor water storages. The water then spilled out across the landscape through the braided rivers system and floodplains of the lower catchment.

One of the great beneficiaries of this flood event was the Narran Lakes wetland system, which receives water during large flows in the lower Balonne River. Flow into the wetlands was aided by Queensland water-planning rules, water from Commonwealth environmental licences and voluntary contributions to environmental flows from irrigators in the catchment. Major flows first reached the wetlands on 29 February and peaked on 20 March – the first significant inflows in 8 years (Figure 24).

Figure 24 Clear Lake, Narran Wetlands, on (from top to bottom) 3, 6 and 19 March
Three photographs showing the filling of the wetlands; the top shows a dry plane, the bottom a sheet of water that stretches to the horizon.

Photos: Commonwealth Environmental Water Office

For more information, go toNatural water systems
Case Study Baiame’s Ngunnhu (Brewarrina Aboriginal fish traps, Barwon River, New South Wales)

Zena Cumpston, 2021

The Brewarrina fish traps (Figure 26) are located within the Barwon River in north-west New South Wales. Although they are located in Ngemba Country, they are highly culturally significant not only to the Ngemba people but to many other Aboriginal nations that are known to have traversal rights related to the shared use of the fish traps. The site is known not only for the use of fish traps but as a significant meeting place for cultural business and law used by many Aboriginal nations, including the Morowori, Weilwan, Barabinja, Nuaalko, Kula, Ualarai and Kamilaroi nations (Rando 2007, MPRA 2015).

The fish traps are traditionally known as Baiame’s Ngunnhu. Baiame is the ancient creator being of many south-eastern Australian Aboriginal nations. The Murdi Paaki Regional Assembly is the peak Aboriginal governance body for the Murdi Paaki Region, representing the interests of Indigenous people throughout western New South Wales. Its website explains (MPRA 2015):

According to Aboriginal tradition, the ancestral creation being, Baiame, created the design by throwing his net over the river and, with his 2 sons Booma-ooma-nowi and Ghinda-inda-mui, built the fish traps to its shape. But according to oral history, the fish traps (and the technology behind them) were inspired by nature – by the pelican, with the traps acting like a pelican’s beak to scoop fish out of the water.

The fish traps are a structure that once encompassed several hundred stone traps, with many family groups across multiple neighbouring nations responsible for their use and maintenance. The traps and the many significant cultural sites that surround them provide a link between pre- and post-contact people and events, as well as showcasing traditional knowledge, Indigenous innovation, lifestyles, intertribal relationships and cultural practice (Rando 2007). In the past, Brewarrina was a place where groups met both formally and informally, largely mediated by the use of the fish traps. Organised gatherings were cultural festivals that included important initiation and other cultural business, as well as intertribal contests and games. It is known that these gatherings attracted huge groups of many thousands of people (Dargin 1976). However, stones were removed by settlers and colonisers to accommodate paddle steamers and were also taken to be used in roads and buildings (Maclean et al. 2012).

Figure 26 A section of the Brewarrina Aboriginal fish traps (Baiame’s Nguunhu) in low flow
Photograph of a riverbed containing an arrangement of rocks and piles of earth arranged to create isolated sections.

Photo: B Moggridge

Baiame’s Ngunnhu continues to be used as a cultural and meeting place by many groups today. The fish traps, although damaged by the many continuing intrusions of colonisation, are still in use (Dargin 1976, Commonwealth of Australia 2005).

In 2005, when the fish traps were included on the National Heritage List, it was noted (Commonwealth of Australia 2005):

Aboriginal people used the unusual combination of a large rock bar, seasonal river flows and suitable local rocks to develop the Ngunnhu. It is nearly half a kilometre long and consists of a series of dry-stone weirs and ponds arranged in the form of a net across the Barwon River. The size, design and complexity of the Ngunnhu is exceptionally rare in Australia … The structure of the Ngunnhu demonstrates the development of a very efficient method for catching fish involving a thorough understanding of dry-stone wall construction techniques, river hydrology and fish ecology … The role of an ancestral being (Baiame) in creating built structures is extremely unusual in Aboriginal society and makes both the structure (Ngunnhu) and the story nationally important.

Baiame’s Ngunnhu is a complex, engineered system that is considered to be one of the oldest human-made structures on Earth, and yet somehow remains little known and under-resourced (Tan 2015).

A 2012 report by CSIRO undertaken as part of a project with Traditional Custodians identified a keen interest from Traditional Owners in collaborative research aimed at illuminating the potential for Indigenous hydrological knowledge to contribute to current water management challenges, and a desire for promotion and conservation of their water-related knowledge (Maclean et al. 2012). This extensive report included work with Ngemba community members to identify the challenges they experience in fulfilling their water management interests and cultural obligations. These challenges include:

  • highly dominant western water paradigms that fail to recognise Aboriginal values and the water needs of the river as a spiritual entity separate from human requirements
  • a lack of leadership capacity building to bolster community efforts to care for Country, and to meaningfully partner and engage with water planners
  • difficulties in resourcing and coordinating beneficial water-related projects and programs within the community
  • the need for implementation of Aboriginal water values to ensure that water allocations bolster the spiritual and environmental health of the old mission billabong, the fish traps and the Barwon River
  • the need to develop local sustainable livelihood opportunities, such as those that would arise from expanded and better-resourced tourism opportunities.

Baiame’s Ngunnhu is a cultural landscape that facilitates a direct link to ancestors and illuminates cultural knowledge, heritage, practice, histories, belonging and wellbeing. The centrality of water to Aboriginal people and all aspects of their lives and heritage is illuminated in this quote from a Ngemba community member (Maclean et al. 2012):

(The) river is the essence, without it we are all dead, spiritually. It plays a crucial part in Aboriginal culture. River holds very special liquid – water, water is not separate from the river, which is what they are doing now (irrigation), the river holds the essence of life, water gives life, not just to you and me, to the trees, the birds, fish, spirit. Water keeps the spirit alive. If the spirit is not working properly, you will be sick … spirit is the foundation of Aboriginal culture. It is an unseen element, a crucial element. (Ngemba, interviewee 1, series 1)

For more information, go toIndigenous water
Case Study Budj Bim

Source: Lucas (2019)

In 2019, Budj Bim Cultural Landscape was entered on the United Nations World Heritage List – the 20th Australian site to make the 1,100-strong list – alongside Uluru, the Daintree Rainforest, the Great Barrier Reef and Melbourne’s Royal Exhibition Building (Lucas 2019).

Budj Bim, on a site about 40 km north of Portland (Figure 28), is the first Australian World Heritage site to be listed exclusively for its Indigenous cultural values. Engineering works built over generations at Budj Bim allowed the Gunditjmara people to trap eels in a complex system of weirs, constructed channels, and holding and growing ponds. These supplied them with enough food to sustain them year-round in villages of stone huts, and to undertake trade. The aquaculture system was created 6,600 years ago and has since been in use by the Gunditjmara people.

Figure 28 Budj Bim Aboriginal aquaculture site, Victoria

Adding Budj Bim to the United Nations World Heritage List challenges the common belief that Australia’s First People hunter–gatherers without permanent settlements. Instead, the site shows evidence of a complex Aboriginal economy and settled lifestyle, in which the country was managed and modified. Most Gunditjmara thought of the landscape in this part of western Victoria as being changed by pastoralists who came from Europe and removed rocks to create vast tracts of grazing land. The Gunditjmara people demonstrated at Budj Bim that manipulation of the landscape was possible in an entirely more sympathetic way (Figure 29).

Figure 29 Budj Bim Cultural Landscape, designed and built by the Gunditjmara people
Photograph of a forested hillside with a dry gully in the foreground.

Photo: Ian McNiven, courtesy Gunditj Mirring Traditional Owners Aboriginal Corporation

In May 2019, the Victorian Government committed $5.7 million for preserving and promoting Aboriginal heritage, in large part to complete the master plan for Budj Bim, in anticipation of an increase in global attention resulting from the World Heritage listing.

For more information, go toIndigenous water
Case Study Gunaikurnai – 2 gigalitre water entitlement

Gunaikurnai Land and Waters Aboriginal Corporation (GLaWAC) represents Traditional Owners from the Brataualung, Brayakaulung, Brabralung, Krauatungalung and Tatungalung family clans, who were recognised in the Native Title Consent Determination, made under the new Traditional Owner Settlement Act 2010, the first such agreement under that Act.

On behalf of its members, GLaWAC will receive 2 gigalitres of unallocated water in the Mitchell River. This is a first and momentous outcome for the Gunaikurnai people, and it recognises the importance of gaining rights to water to restore customary practices, protect cultural values and uses, gain economic independence and heal Country. It is an important outcome of the Water for Victoria policy, released by the Victorian Government in 2016. Securing water rights for the Gunaikurnai people puts the ‘Waters’ into the Land and Waters Aboriginal Corporation for the first time, and GLaWAC thank all our partners in government and the local community for their support.

Reference: Mooney & Cullen (2019)

National Cultural Flows Research Project 2018

For more information, go toIndigenous water
Case Study Lake Hume and River Murray low dissolved oxygen event, February 2021

Source: MDBA Water Quality Advisory Panel, February 2021

Lake Hume is located near Albury (New South Wales)–Wodonga (Victoria) and is the main operating storage of the River Murray system, supplying water for irrigators, cities and towns, and environmental purposes.

During the 2019–20 bushfires, approximately 32% of the Lake Hume catchment was severely burned, making it highly susceptible to increased mobilisation of sediment, ash, nutrients and other contaminants following rainfall events.

In February 2021, significant rainfall was recorded across the bushfire-affected areas of the upper Murray, resulting in run-off containing large amounts of ash, sediment and debris. It also contained large amounts of dissolved organic carbon, iron, manganese and nutrients.

With seasonally warmer temperatures, this material triggered biological and chemical processes within Lake Hume that saw development of a significant layer of water with very low dissolved oxygen.

Across the warmer months, Lake Hume typically becomes layered with thermally stratified water. During the event, the water with little or no dissolved oxygen occurred in a layer at a depth of approximately 20 m, which is around the same level as the Hume Dam offtakes.

This resulted in water being released with low dissolved oxygen levels into the River Murray immediately downstream from Hume Dam with the following impacts:

  • Murray crayfish reported to be crawling out of the water in response to low dissolved oxygen
  • ‘rotten egg’ odour (hydrogen sulfide) and orange staining of vegetation and some of the crayfish due to oxidation of iron and manganese
  • water quality supply issues reported by Albury City Council, with ‘rotten egg’ odour and discolouration.

The Murray–Darling Basin Authority responded by adjusting operations to assist with aeration of the water, and applying compressed air to water flowing through the Hume Dam hydropower station.

Ongoing response includes upgrades to upstream and downstream water quality monitoring sites, adaptive management of releases (if required) and engagement of water quality expertise to quantify potential risks.

For more information, go toWater quality
Case Study Pama Narrows (Yorta Yorta), also known as Barmah Choke

Source: Yorta Yorta Nation and Elders

The Murray River determines the New South Wales and Victorian borders. The Barmah Choke restricts the flow capacity of the Murray River to around 9,600 megalitres (ML) per day; this has decreased to 7,000 ML per day or less due to the accretion of sands on the Barmah Choke (Pama Narrows) riverbed. River managers need to consider the impacts of using the Choke to deliver water downstream for agricultural and consumptive purposes (MDBA 2021e).

The Elders of Yorta Yorta Nation have begun a Yorta Yorta investigation into water impacts on the Pama Narrows to determine the impact of flow regulation on Yorta Yorta knowledge, stories, people and sites, including middens, mounds and scarred trees. Yorta Yorta have engaged a drone specialist to assist with telling their story visually. The investigation aims to preserve their traditional story, culture and identity intact.

For more information, go toClimate change
Case Study Almond production in Australia

Zena Cumpston

In 2021, 123,000 tonnes (t) of almonds are projected to be harvested in Australia. Almonds now represent Australia’s most valuable horticultural crop, and Australia is the world’s second largest supplier (ANIC 2019, Granwal 2020, Jeffery et al. 2021). For each tonne of almonds sold in Australia, 2.6 t are exported; in 2019–20, these were sold to more than 50 countries, with the almond industry yielding $772.6 million (Almond Board of Australia 2021).

In 2000, Australia had approximately 3,546 hectares (ha) of almond tree plantations. By 2019, the rapid expansion of this industry had increased almond-growing land to 53,014 ha – a 900% rise in less than 20 years (Schremmer 2020). The fact that much of this expansion has occurred in a short time, particularly within the highly compromised Murray–Darling Basin, invites questions about the water needs of almonds and the role of this crop in the multiple pressures on inland water and the environment in Australia more widely (Bleby 2019).

In Australia, almonds use triple the amount of water required to produce wheat or feed grain; they need at least 8.5–10 megalitres of water per hectare during a growing season that stretches from October to April (Fulton et al. 2019). The underlying need for a reliable supply of water sees almond crops planted along river systems that are facing increasing pressure from prolonged dry periods. Almond crops have grown by 50% in the Murray–Darling Basin since 2016, despite their substantial water requirements in a geographical area with severe and catastrophic water security issues (Mann 2021). Almonds deplete biodiversity because they are grown as monocultures, with industrial farms stripping the ground around the trees bare to treat for insects and fungi. Also concerning is that the pesticides used to ensure high yields are particularly lethal to bees (McGivney 2020), and almond cultivation requires more hives for pollination than any other crop (Mann 2021).

For more information, go toIndustry