Oil and gas exploration and development in the Lake Eyre Basin: distribution and consequences for rivers and wetlands, including the Coongie Lakes Ramsar Site

Keywords: biodiversity, coal seam gas, floodplain development, fragmentation, petroleum, roads, unconventional gas, wells, wetland conservation.

Freshwater resources around the world are under increasing anthropogenic pressure, with resulting widespread degradation of ecosystems and their services (Dudgeon et al. 2006; Kingsford et al. 2016; Xi et al. 2021). Much of this degradation has occurred through the draining of wetlands and regulation of river flow, including the building of dams and diversion of water and development on floodplains (Micklin 1988; Richardson et al. 2005), reducing frequency and duration of flows and frequency and extent of flooding (Lemly et al. 2000; Kingsford et al. 2006). Developments on floodplains are built to protect urban or agricultural areas (Dang et al. 2016) or sometimes to capture water from the floodplain and divert this into private storages for later use (Steinfeld and Kingsford 2013). As a result, many floodplains on developed rivers of the world have been destroyed (Tockner and Stanford 2002; Kingsford et al. 2006; Liu and Xia 2004), detrimentally affecting flood-dependent biodiversity (Liu et al. 2004; Hupp et al. 2009; Steinfeld and Kingsford 2013; Kingsford et al. 2015).

In addition, pollution of freshwater ecosystems from multiple causes is increasingly affecting freshwater ecosystems around the world (Smith 2003; Junk 2013; Reid et al. 2019). This includes reduced water quality from exploration and development of sand, and oil and gas (Ramos et al. 1994; Varol 2011; Olmstead et al. 2013; Yao et al. 2019). Oil and gas production interrupts sediments, elevating concentrations of different elements, including sodium, chloride, barium, strontium and lithium (Olmstead et al. 2013; Cozzarelli et al. 2021). Further, oil and gas production wastes can degrade floodplain vegetation (Strizhenok and Fedorova 2020). Such multiple threats to floodplain rivers from these anthropogenic factors challenge effective conservation and protection of large rivers, particularly over large catchments.

Nomination of wetlands of international significance under the Ramsar Convention provides some conservation focus for governments (Kingsford et al. 2021a), along with protected areas (Saunders et al. 2002). Unfortunately, neither approach adequately protects flow and flooding regimes from anthropogenic threats. For example, three Ramsar Sites, which are also protected areas, namely the Macquarie Marshes, Gwydir Wetlands, Lower Lakes and Coorong and Murray Mouth, in Australia’s Murray–Darling Basin have degraded because of inadequate management of flow and flooding regimes (Kingsford and Thomas 1995; Powell et al. 2008; Kingsford et al. 2011). The Australian Government formally notified the Ramsar Secretariat that these Ramsar Sites had experienced changes in ecological character, resulting from anthropogenic pressures, with declining biota (Kingsford 2000, Kingsford et al. 2015).

The rivers of the Lake Eyre Basin largely remain free-flowing, supporting significant wetland and floodplain areas (Kingsford et al. 1998; Kingsford 2017a), including the Coongie Lakes Ramsar Site (Fig. 1), and significant biodiversity (Kerezsy et al. 2014; Arthington and Balcombe 2017; Kingsford et al. 2017a). They support 33 wetlands of national importance, identified by the Northern Territory, New South Wales, Queensland and South Australian Governments (Fig. 1; Supplementary Table S1). Many of these wetlands depend on river flows originating in northern and north-eastern Queensland on the Cooper Creek and Georgina–Diamantina River systems (Fig. 1), rivers described as discontinuous, with non-sinuous channels that decline in size downstream (Larkin et al. 2020). In large flood sequences, large flow volumes track through the system, inundating extensive areas of floodplains, lakes and other wetlands (Bunn et al. 2006; Costelloe et al. 2006; McMahon et al. 2008; Kingsford et al. 2014; Kingsford 2017a; Mohammadi et al. 2017). These wetlands sometimes extend over more than 60 km across the floodplain (Fig. 1), supporting booms of fish breeding and high biological production (Arthington and Balcombe 2017), also providing for highly significant cultural values (Gorringe 2017) and other ecosystem services, including grazing for livestock (Brook 2017; Emmott 2017) and tourism (Wright 2017). The rivers are largely unregulated, with no major dams and small diversions of water for irrigation (Kingsford 2017a), making the rivers of the Lake Eyre Basin among the few remaining free-flowing rivers of the world (Grill et al. 2019). It was this rare largely free-flowing status and the significant cultural and environmental values and ecosystem services supplied, that resulted in the Lake Eyre Basin receiving the National River Prize in 2014 and the International River Prize in 2015 (Kingsford et al. 2017b).

Fig. 1.  Lake Eyre Basin and its two major rivers (Georgina River, G; Diamantina River, D; and Cooper Creek, C) in central Australia (inset) and the Cooper Basin (geological, orange), predominantly in Queensland (Qld), South Australia (SA) and the Northern Territory (NT; and a small part in New South Wales, NSW), and their floodplains and wetlands (blue), including the 33 nationally important wetlands (green polygons, see Table S1; names corresponding to numbers), including the Ramsar-listed Coongie Lakes (green triangle, 11RS), incorporating Coongie Lakes National Park (CLNP). Locations of the three highest-density oil and gas production infrastructure areas (wells, well pads, roads, water storages) are also identified on the floodplains: two within the Coongie Lakes Ramsar Site (Gidgealpa, GI; Tirrawarra Swamp, TS) in South Australia and one upstream (Cooper Creek–Wilson River floodplain confluence, CCW) in Queensland. Flows in Cooper Creek were measured at Nappa Merrie (N).

Most of the Lake Eyre Basin falls within the jurisdictions of Queensland, South Australia and the Northern Territory (and a small region of New South Wales, Fig. 1). Public concern about potential anthropogenic effects on flows and flooding, primarily irrigation (Walker et al. 1997; Kingsford et al. 1998), drove Australian, Queensland and South Australian Governments to commit to protect flow variability of the rivers in the Lake Eyre Basin Agreement area (2000, Table 1, Kingsford et al. 2017b), including the two main rivers, the Georgina–Diamantina rivers and the Cooper Creek (Fig. 1). The resulting Lake Eyre Basin Intergovernmental Agreement, signed in 2004 by the Northern Territory Government, was supported by a Community Advisory Committee, including First Nations representatives, and a Lake Eyre Basin Scientific Advisory Panel, with senior officers from each government and a Ministerial Forum. More recently, there is increasing concern about existing and future mining developments, particularly oil and gas exploration and production (Crothers 2017; Mudd 2017), and the subsequent disruption of flow and flooding patterns and pollution potential from wastewater (Gordalla et al. 2013), affecting its national and global conservation importance. Governments have also further committed to protect the rivers (Table 1).

Table 1.  Key political conservation protection and development instruments (strategies, legislation, policies, assessments) relevant to the rivers and floodplains of the Lake Eyre Basin.

The Queensland Labor Government introduced Wild Rivers legislation in 2013, but this was revoked in 2014 by the Liberal–National Party (Kingsford et al. 2017b; Tan 2017; Table 1). Subsequent Queensland Labor Governments committed to the protection of Queensland floodplains of the Lake Eyre Basin by prohibiting development within floodplain areas (called sensitive areas), but such policies are yet to be implemented. In South Australia, much of the focus has been on protection and management of the large area included in the Coongie Ramsar Site, including Coongie Lakes National Park (Fig. 1, Kingsford et al. 2021b). Under the Environment Protection and Biodiversity Conservation Act 1999 (EPBC Act 1999), developments that potentially affect Ramsar Sites are deemed matters of national environmental significance, assessable as potential controlled actions. There is increasing concern about existing and future mining developments in the Lake Eyre Basin, particularly oil and gas exploration and disruption of flow and flooding patterns (Crothers 2017; Mudd 2017), with additional concerns about pollution (Gordalla et al. 2013).

There is a history of more than six decades of oil and gas exploration and production in the Lake Eyre Basin, since 1954, focused primarily on the Cooper Basin, the geological basin underlying some of the floodplains of Cooper Creek (Mudd 2017, Fig. 1), with its 256 gas fields and 166 oil fields (Lech et al. 2020). In 2014, a record 119 petroleum wells were drilled in the South Australian part of this basin (Lech et al. 2020). Globally and nationally, there is an increasing shift from production of conventional to unconventional gas (McGlade et al. 2013; Bista et al. 2017). Production methods and potential impacts are different. Unconventional gas is distributed regionally and is generally dispersed, which requires more extraction wells, horizontal drilling and hydraulic fracturing (Jackson et al. 2013). The Queensland Government promoted development of unconventional gas (tight gas, shale gas, coal seam gas and deep goal gas) in its 2014 strategy for the Cooper Basin (Table 1, Queensland Department of Natural Resources and Mines 2014). Tight and deep coal gas were identified as having high prospectivity, whereas shale gas was medium in some areas, primarily requiring hydraulic stimulation (Lech et al. 2020), achieved using ‘fracking’. At least 80 wells were drilled to target shale, tight and deep coal gas, with the first vertical shale gas well being drilled in 2011 (although not productive) and deep coal gas production starting in 2015 (Tirrawarra South 1; Lech et al. 2020).

There is increasing concern about identified ecological and health impacts of oil and gas exploration and production, well documented in the rapidly increasing industry of the United States (Adgate et al. 2014; Vengosh et al. 2014). At the same time, pressure is increasing to develop unconventional gas resources of the Lake Eyre Basin, particularly given the national political imperative for a ‘gas-fired’ energy recovery, focused on ‘unlocking’ additional gas supplies, driven by the 2021 National Gas Infrastructure Plan (Australian Government 2021). Further, the Cooper Basin was identified with considerable ‘undiscovered’ gas potential for future production (Australian Government 2021). This made the Cooper Basin a focus for the bioregional assessment to determine potential coal seam gas and coal mining impacts on water-dependent ecosystems (Holland et al. 2021). Despite this, there is no analysis of the intersection between oil and gas production on the entire rivers and floodplains of the Lake Eyre Basin, with most reporting being done at the scale of underlying geological basins (e.g. Lech et al. 2020). This is despite an acknowledgement by the Australian Government that potentially 1613 km² of the Cooper Creek floodplain could have small flood runners blocked or obstructed by construction activities for roads and development facilities (Holland et al. 2021).

We aimed to identify the distribution of current and potential future growth of infrastructure (wells, well pads, roads and water storages or ponds) in relation to oil and gas exploration and production on the rivers and floodplains of the Lake Eyre Basin. These will have increasing impacts on hydraulic movement of water and flooding, fragmenting landscapes and increasing pollution, with long-term impacts on cultural and environmental values of the rivers, including the Coongie Lake Ramsar Site. We had the following three specific objectives: (1) to determine the number of wells and associated structures and their growth over time, with a focus on the Coongie Lakes Ramsar Site and existence of any referrals under the EPBC Act 1999; (2) to examine growth in structures (wells, well pads, roads, water storages or ponds) in the three highest-density infrastructure focus areas (Fig. 1) and; (3) to investigate future oil and gas exploration and production (licences, well pads) on the floodplains of the Lake Eyre Basin. We discuss our findings in relation to this development and the potential impacts on the rivers and floodplains of the Lake Eyre Basin, in the context of the policy and legislative frameworks for conservation currently in place.

We first compiled and mapped a ‘floodplain layer’ encompassing all of the waterbodies, including rivers, lakes and other wetlands, across the Lake Eyre Basin, separately obtained for the Northern Territory (Northern Territory Government 2021), Queensland (Queensland Government 2021a), South Australia (South Australian Government 2020) and New South Wales (State Government of NSW and Department of Regional New South Wales 2010; Fig. 1). We also mapped the 33 wetlands of national importance, using the Directory of Important Wetlands in Australia (DIWA) Spatial Database (Australian Government Department of the Environment and Energy 2018).

We identified and mapped infrastructure using available datasets and current and historical imagery on Google Earth and QGIS. All analyses on the numbers and the extent of existing oil and gas infrastructure were confined to the floodplains. We mapped existing wells by overlaying data for oil and gas infrastructure over the floodplain layer at Coongie Lakes Ramsar Site, in the Cooper Creek, Diamantina River and Georgina River catchments and at jurisdictional scales (i.e. Queensland, South Australia and Northern Territory) over time. We divided existing data on wells into the following three periods: before and during 2000, when the Lake Eyre Basin Agreement was signed; 2001–2014, the period during active development of river protection policies by governments including Wild Rivers legislation in Queensland (Tan 2017); and subsequently, up to latest available data (2021). Well locations were identified spatially and temporally using Queensland Government (2021c) and South Australian Government (2021a) data. There were no wells on the floodplain areas of the Lake Eyre Basin rivers in the Northern Territory (Northern Territory Government 2019) or New South Wales (State Government of NSW and Department of Regional New South Wales 2011). For wells, we tracked annual cumulative increase in numbers over time (1958–2021). We also overlayed the 33 wetlands of national importance over the distribution of this infrastructure to determine relative categorical impact in relation to proximity of wells (Table S1).

We also mapped the current (2018–2021, dependent on availability of imagery) extent of oil and gas exploration and production infrastructure (wells, well pads, roads, storages) on the floodplains of the Coongie Lakes Ramsar Site and the Cooper Creek–Wilson River floodplain confluence (Fig. 1). This included two of the three highest-density infrastructure areas (Fig. 1). For these three areas, we mapped changes over three time periods: oldest available satellite imagery (c. 1985), the most recent available high-resolution imagery (2020–2021 on Google Earth and QGIS at 0.5-m resolution) and a date between when there was cloud-free imagery (2006, 2013 and 2014). For each of these areas, we mapped the surface infrastructure, including wells, number and sizes of well pads, length of roads and number and size of water storages intersecting the floodplain. Roads were identifiable as straight, cleared passages connecting with other infrastructure on the floodplain. Well pad areas were identified as areas disturbed or cleared around each well. Storages were usually identified from their rectangular structure, presence of water or historical presence of water (confirmed using historical imagery; any not adequately identified were labelled as ‘uncertain’). We used QGIS to map infrastructure. We also visually assessed effects of this infrastructure on flooding using Sentinel imagery available after 2015 (Sinergise Ltd 2021), identifying one of the higher floods in the area, guided by flow data at Nappa Merrie on Cooper Creek (Fig. 1, Station 003103A; Queensland Government 2022), given its proximity to the high-density infrastructure focus areas (Fig. 1). We also compiled a list of referrals to the EPBC Act 1999 (data from http://epbcnotices.environment.gov.au/referralslist/) in relation to any developments that were either within the Coongie Lake Ramsar Site or upstream where they could affect its environmental value and were therefore assessable as potential controlled actions.

To determine the potential distribution of future oil and gas infrastructure on wetlands, we mapped wells that were at exploration, appraisal and development stages, given that all three stages may require infrastructure (such as well pads, access roads, drilling), potentially affecting water flows and flooding. We mapped the physical extent of leases and authorities to produce oil and gas across all catchments. Authorities are held and regulated separately by states and territories, with different definitions. For Queensland, we mapped four categories for oil and gas exploration and development, specified under the Petroleum and Gas (Production and Safety) Act 2004, including the authority to prospect (ATP), potential commercial area (PCA), petroleum lease (PL) and petroleum survey licence (PSL), obtained datasets from the Queensland Spatial Catalogue, provided by the Department of Resources (Queensland Government 2021c). An ATP allows exploration for petroleum and gas, including testing and evaluating feasibility of petroleum production; it can also be declared as a potential commercial area (PCA) for resource production. A PL permits exploration and testing for petroleum production, whereas a PSL allows entry to land to survey suitability for proposed infrastructure. For South Australia, we mapped the distribution of the three relevant licences required for oil and gas exploration and development under the Petroleum and Geothermal Energy Act 2000, including a petroleum exploration licence (PEL), petroleum retention licence (PRL) and petroleum production licence (PPL). We sourced these datasets from South Australian Resources Information Gateway (SARIG; South Australian Government 2021b). A PEL authorises exploration for resources to determine production feasibility; PRLs entitle exploration until commercialisation and; PPLs allow production in PEL- or PRL-covered areas. For the Northern Territory, we mapped three licence types listed under the Petroleum Act 1984, including the petroleum exploration permit, petroleum production licence, petroleum retention licence, as well as the petroleum acreage releases, which allow for release of land and multiple applications for permits simultaneously. We sourced these datasets from the Northern Territory Government data portal (Northern Territory Government 2014). We used QGIS to map where licences intersected all catchments.

There have been a range of significant policies and legislative instruments for the development and protection of the rivers of the Lake Eyre Basin, particularly the Georgina–Diamantina and Cooper Creek catchments (Table 1). Competing drivers for protection or development, particularly in relation to river flows in Queensland and South Australia, remain largely unreconciled. All Governments for the Lake Eyre Basin committed to the protection of the natural variability of flows, under the Lake Eyre Basin Intergovernmental Agreement in 2000 (Table 1), further developed into protection of flood flows in Queensland under Wild Rivers legislation, which was subsequently repealed (Table 1). By contrast, policies to promote exploration and production of oil and gas have increased recently, particularly through commitment to accelerate development of deep gas and oil resources, including removal of ‘barriers’ to this development (Table 1). Most recently, the Queensland Government announced that a stakeholder advisory group development would be resolving the balance between environmental and economic considerations in the Queensland part of the Lake Eyre Basin (Table 1). Legislation and policies that drive development or protect the rivers and their flows remain largely unresolved, and challenging because of clashing objectives.

Within the Lake Eyre Basin, there are 33 wetlands of national importance, mostly in the catchments of the major rivers: Georgina River (8), Diamantina River (7) and Cooper Creek (12), as well as Lake Eyre (Fig. 1, Table S1). This also includes the Ramsar-listed Coongie Lakes in South Australia, which covers 21 889 km², predominantly in the Cooper Creek catchment (Fig. 1). The two remaining wetlands of national importance are in the Macumba River catchment, in the western part of the Lake Eyre Basin, flowing east to Lake Eyre (Fig. 1). Wetlands of national importance covered 5.45 × 10⁶ ha, although a large terrestrial area was included in the Coongie Lakes Ramsar Site (Fig. 1), with >32 × 10⁶ ha of wetland area (Supplementary Table S2). Most of the floodplain area is in the Queensland parts of Cooper Creek, Georgina River and Diamantina River, with the eastern flowing rivers and lakes in South Australia the next-most prominent and small areas in New South Wales (Table S2).

The 831 existing oil and gas wells drilled on the floodplains of the Lake Eyre Basin rivers were overwhelmingly concentrated on the floodplains of the Cooper Creek (98.6%), with relatively few on the floodplains of the Georgina and Diamantina rivers (Fig. 2, Table 2). The highest density of wells was on the floodplains of Cooper Creek in South Australia, with the density being more than three times the next-highest density in the Queensland part of the Cooper Creek catchment (Fig. 2, Table 2). The earliest wells drilled on these floodplains were in 1958 in Queensland and 1963 in South Australia (Fig. 3a). There was then rapid development of wells from the early 1980s and this continued for the period of data assessment up to 2021 (Fig. 2a). Approximately half of the wells were drilled on the floodplains before 2001, with subsequent development of the other half, at a rate of 19 wells per year since 2001, predominantly in the Cooper Creek catchment, increasingly in Queensland compared with South Australia (Table 2, Fig. 2). Consequently, the number of wells on the floodplains of the Lake Eyre Basin rivers is now higher in Queensland than in South Australia, exceeding the number in South Australia in 1997 (Table 2). There were few wells on the floodplains of the Georgina and Diamantina rivers, all in Queensland, with little increase after 2001 (Table 2, Fig. 2).

Fig. 2.  Distribution and time period of oil and gas wells (closed circles: <2001, yellow; 2001–2014, white; >2014, red, note not actual size) developed on the floodplains (including other wetlands) of the Lake Eyre Basin rivers in Cooper Creek, Diamantina River and Georgina River catchments in Queensland and South Australia (see also Table 1), with concentrations expanded, including the three highest-density areas of oil and gas wells (Gidgealpa, GI; Tirrawarra Swamp, TS; Cooper Creek–Wilson River floodplain confluence, CCW), also showing the Cooper Basin (orange).

Table 2.  Distribution, numbers, densities of oil and gas wells drilled (up to 2021) on the floodplains and other wetlands of the Lake Eyre Basin’s three major rivers.

Fig. 3.  Trajectories of development of oil and gas wells on (a) the floodplains and other wetlands of the Lake Eyre Basin rivers, including total number of wells (black) and number of wells in the Cooper Creek catchment in Queensland (red), Cooper Creek in South Australia (green dashed) and the Georgina and Diamantina catchments in Queensland (blue; see also Fig. 2 and Table 1) and (b) total number of wells built within the boundary of the Coongie Lakes Ramsar Site (red continuous), including those in terrestrial areas (orange dashed) and on the floodplains (blue dotted).

Within the Cooper Creek catchment, the Ramsar-listed Coongie Lakes Site had 4494 km² of floodplain (Fig. 1). This trajectory of development of wells on the Cooper Creek catchment floodplains was also reflected in the Coongie Lakes Ramsar Site (Fig. 1–3), where there was a higher rate of development of wells on its terrestrial ecosystems than on its floodplains ecosystems (Fig. 3b). After the 1987 gazettal of the Coongie Lakes Ramsar Site as a wetland of international importance (Table 1), the number of wells in the Coongie Ramsar Site increased five times from 233 to 1236 wells. This included more than a three-fold increase in the number of wells on the floodplains, from 95 to 296 wells, and more than a six-fold increase in the numbers of wells on terrestrial ecosystems, from 138 to 940 wells.

The wells on the floodplains also had associated infrastructure (Table 3). For the 296 wells on the Coongie Lakes Ramsar Site floodplain, there was a similar number of well pads and more than 869 km of road, as well as 392 storages (Table 3). Together the well pads and storages covered 5.83 km², a relatively small part (0.13%) of the entire floodplain. The two highest-density areas for wells within the Coongie Lakes Ramsar Site, Tirrawarra Swamp and Gidgealpa floodplain (Fig. 1, 2), accounted for 103 wells on the floodplains, more than one-third of all wells. For the Tirrawarra Swamp focus area, the number of wells (54) on the floodplains doubled after 1985, with 50 well pads covering 46 ha, at a density of 0.58 km⁻². For the Gidgealpa floodplain focus area, the number of wells (49) increased more quickly, with subsequent roads and storages and 48 well pads covering 26 ha at a density of 0.42 km⁻² (Fig. 4, Table 3).

Table 3.  Number and distributions of oil and gas infrastructure on floodplain areas of the Lake Eyre Basin rivers.

Fig. 4.  Imagery from three focus areas for development of wells and infrastructure (see Fig. 1), two within the Coongie Lakes Ramsar Site, namely (a) Tirrawarra Swamp (Google Earth, 1985, using Landsat and Copernicus; 2014 using Maxar Technologies; 2020 using ESRI Satellite imagery), and (b) Gidgealpa floodplain in South Australia, and the third (c) the Cooper Creek–Wilson River floodplain confluence in Queensland at different dates, vertically, with the first three images showing the growth in infrastructure (wells, circles; well pads, orange; roads, yellow lines; and storages, blue) over time (see Table 2 for details). The fourth-lowest image (Sentinel image) shows a false colour image of a small flood (in 2016 for (a), (b) and 2019 for (c)), displayed with band 12 (shortwave infrared), band 8A (near infrared), and band 4 (red) as red, green and blue, with vegetation following flooding showing green because of its high reflectance in the near infrared, whereas water is blue and black with its low reflectance in both near and shortwave infrared. Imagery is from Landsat and Copernicus (1985), Maxar Technologies (2006, 2007 2011, 2014, 2020), ESRI Satellite imagery (2020, 2021) and the Sentinel Hub (2016, 2019).

There was a small flood in 2016 of 685 434 ML (Supplementary Fig. S1), significantly below the annual volume of large floods (Supplementary Fig. S2). For Tirrawarra Swamp, there was some evidence indicating alterations in flooding patterns, in relation to the road infrastructure (i.e. differences in colours either side of roads; Fig. 4a). These disrupted patterns of flooding, including potential overflow from storages, in relation to this flood were more easily identified in comparison to a nearby floodplain where there was no oil and gas development infrastructure (Fig. S2). A similar flood on the Gidgealpa floodplain was not sufficiently high to show any differences in flooding patterns in relation to infrastructure (Fig. 4b).

For the Cooper Creek–Wilson River floodplain confluence, there was rapid development of wells after 1985, with the number of wells more than doubling after 2006 (Fig. 4, Table 3). This included ∼100 km of road and 74 storages, including some that were uncertain. There was relatively little evidence for a clear effect on flooding regimes for the 2019 flood (Fig. 4).

There were eight actions referred for potential controlled actions, under the EPBC Act 1999, of which five, one and two respectively, related to Cooper Creek, the Diamantina River and Georgina River (Supplementary Table S3). The earliest of these was in 2002 and the latest 2014. There were referrals to two pipelines (10 km, Cooper Creek–Wilson River floodplain and ∼1000-km pipeline from Cooper to Abbot Point); two specific to seismic surveys on the Cooper floodplain affecting 19.59 and 126 km² of floodplain in the Cooper Creek–Wilson River floodplain; two related to seismic surveys (970 km) and eight exploration wells (including hydraulic fracturing, rigs and clearing on the Georgina River; covering 1.4 × 10⁶ ha). There was also one referral to six petroleum wells (6.32 ha of drill sites and camp, 7.93 ha of access tracks and 32.29 ha of existing seismic line, access tracks and workers’ camp). Only the pipeline from Cooper to Abbot Point was deemed a controlled action, originating in terrestrial areas east of the Cooper Creek floodplain (Table S3).

For areas of potential future development of oil and gas, a range of authorities for exploration and development intersected the floodplains of the large rivers of the Lake Eyre Basin (Fig. 5, Table 4), covering 4.94 × 10⁶ ha of floodplain (Table 4). Potential areas for future oil and gas exploration and development are dominated by authorities to prospect in application or granted for the Queensland part of Cooper Creek (Table 4, Fig. 5). These are predominantly focused on the channel country of Cooper Creek, where there is widespread flooding, around Windorah and the Cooper Creek–Wilson River floodplain confluence (Fig. 1, 5). In South Australia, petroleum production licences (also potentially for gas) are only in the Cooper Basin and other basins including the Lake Frome and Hay River (Fig. 5, Table 4). The Georgina River catchment contains only one petroleum exploration licence permit (granted). The Diamantina River and Cooper Creek hold petroleum retention licences and petroleum exploration licences (application and granted). Petroleum leases encompass large areas of the Georgina River, Diamantina River and Cooper Creek catchments in both South Australia and Queensland. There are also a range of licences covering the Northern Territory, although the extent of intersection with floodplains could not be resolved (Fig. 5, Table 4). For Cooper Creek in Queensland, a large proportion of the petroleum leases intersect with the floodplain. There is a high density of leases in the South Australian portion of the catchments, as well as the Southern Cooper Creek catchment in Queensland. In Queensland, the Georgina and Diamantina catchments have only one lease type, namely, authority to prospect. The Cooper has all four types, including petroleum survey licences, authority to prospect, potential commercial areas and petroleum leases (granted and application). Combining all licencing, 47, 5 and 23% of the respective floodplains of Cooper Creek, Diamantina River and Georgina River in Queensland and South Australia are covered by oil and gas exploration and production licences (Table 4). Across these three catchments, there was 31% of the floodplain area in the Lake Eyre Basin covered by these licences (noting that there was no estimate possible for the Northern Territory). The amount varied across states within catchments, with less than half of Cooper Creek under licence in Queensland (41%), but most (91%) in South Australia; 27% of the Diamantina River in South Australia and little in Queensland and; 23 and 72% respectively of the Georgina River in Queensland and South Australia (Table 4). The total area of petroleum leases on the floodplain is 2.32 × 10⁶, 0.22 × 10⁶ and 1.03 × 10⁶ ha for the Cooper Creek and Diamantina and Georgina rivers respectively (Table 4). For Queensland, the type of authority with the largest area is the authority to prospect (Cooper, 1.30 × 10⁶ ha; Diamantina, 9294 ha; Georgina, 1.01 × 10⁶ ha; Table 4). For South Australia, in the Cooper Creek retention licences make up the largest area (0.22 × 10⁶ ha), compared with the Diamantina River where exploration licences (application and granted) have the largest area with a combined total of 0.61 × 10⁶ ha (Table 4). The Georgina River has a much smaller area of authorities in South Australia, with the exploration licences (application and granted) making up 13 499 ha (Table 4). South Australia’s Lake Frome and Hay River catchments had high proportions (respectively 65 and 77%) of their floodplains covered by licences in comparison to low coverage of the Finke River (Table 4, Fig. 5).

Fig. 5.  (a) Distribution of different oil and gas licences across the floodplains and wetlands of the Lake Eyre Basin in Queensland and South Australia, with insets providing more detail for different areas on the floodplains of Cooper Creek (see also Table 2) and (b) the Cooper Basin overlaying the Cooper Creek catchment. There are different categories of oil and gas licencing for each state, including for the Northern Territory (petroleum retention licence, yellow; petroleum production licence granted, pink; petroleum exploration permit application, orange; exploration permit granted, white hatched; acreage release areas, purple hatched), Queensland (petroleum lease application, green hatched; petroleum lease granted, pink; potential commercial area, yellow; authority to prospect, white hatched; petroleum survey licence, purple hatched) and South Australia (petroleum exploration licence, white hatched; petroleum exploration application, orange; petroleum retention licence, yellow; petroleum production licence, pink). Where different licences overlapped (Table 4), only the licence most progressed for development shown.

Table 4.  Distribution and areas of different petroleum and gas authorities in relation to floodplain areas.

The world’s freshwater ecosystems, including its wetlands, are in serious decline, affecting biodiversity and ecosystem services (Vörösmarty et al. 2010). Most flow- and flood-dependent aquatic biodiversity require natural flow and flooding regimes and their connectivity, without which, much of this biota inevitably declines (Dudgeon et al. 2006; Kingsford et al. 2015). Despite the establishment of the Ramsar Convention for protecting wetlands of international importance, which has been operating for more than 50 years (Kingsford et al. 2021a), many Ramsar-listed Sites continue to degrade because of inadequate management of threats (Davidson et al. 2018). Globally, the most serious driver of these declines is alteration to water sources, affecting flow and flooding regimes (Lemly et al. 2000; Dudgeon et al. 2006). Much of the current global understanding in relation to impacts on flooding regimes, particularly for floodplains, relates to the effects of building dams and subsequent diversion of water upstream (Nilsson et al. 2005; Vörösmarty et al. 2010). By contrast, understanding of the effects of infrastructure on floodplains remains reasonably poor (Kingsford 2015). This may be because many of the world’s floodplains were destroyed or degraded by urbanisation and irrigated agriculture, combined with river regulation reducing inundation, before adequate assessment (Tockner and Stanford 2002; Kingsford 2015). Our examination of the issue in one of Australia’s most important and larger river systems, the Lake Eyre Basin, has clearly identified impacts, with significant future potential impacts on ecosystems, including on the Coongie Lakes Ramsar Site.

The oil and gas industry has a significant and rapidly growing infrastructure footprint on the floodplains of the Lake Eyre Basin rivers, with most of the more than 800 wells concentrated in the Cooper Creek catchment (Fig. 2, Table 2). The current distribution of wells was available from Government databases but had not been not compiled, or infrastructure assessed, until we did our catchment-wide assessment, superimposed on the floodplains. Similarly, there were data for future licensing of oil and gas development but again these were not compiled across catchments, covering jurisdictions and each of the rivers’ floodplains. The lack of such a comprehensive assessment may reflect the remoteness of the area and a relatively low population (∼60 000 over the Lake Eyre Basin; Measham and Brake 2009). Nevertheless, the potential impacts on the conservation of ecosystem services will be significant and threaten the Lake Eyre Basin’s status as one of the world’s great free-flowing rivers (Kingsford et al. 2017b; Grill et al. 2019) with its 33 nationally important wetlands (Fig. 1, Table S1), including the Ramsar-listed Coongie Lakes (Kingsford et al. 2021b). The trajectory of this development has increased (Table 3, Fig. 2), despite commitments by governments to protect variability of flow and flooding regimes of the rivers of the Lake Eyre Basin, under a range of policy and legislative instruments (Table 1). Future oil and gas production is predicted to develop unconventional gas resources, with much potentially greater infrastructure development; this is reflected in the extensive coverage of authorities to prospect and proposed and granted licences within the Cooper Creek catchment and Georgina River catchment and to a much lesser extent in the Diamantina River catchment in Queensland (Fig. 5, Table 4). These extend across significant areas of floodplain (Table 4). Given that wells and well pads are likely to occur in areas with existing infrastructure and close to pipelines, it is likely that some of the areas with already well developed footprints for oil and gas production on the floodplain (Fig. 2, 4) may have increased concentrations of infrastructure in the future.

The Ramsar-listed Coongie Lakes Ramsar Site (Fig. 1) has also been the focus of significant development, reaching 296 wells on its floodplain areas (Table 2), most occurring after it was gazetted as a wetland of international importance to protect its wetland values in 1987 (Table 1, Fig. 3b). Given it is a matter of national environmental significance, it is not clear what assessment processes or referrals occurred, under the EPBC Act 1999. Clearly, relatively more of this development has occurred on terrestrial systems within the Ramsar-listed area, rather than on the floodplains (Fig. 3b). But each well on the floodplain was associated with a well pad (almost a 1:1 ratio) and more than 850 km of roads and more than 400 storages (Table 3). Approximately one-third of all the wells in the Coongie Lakes Ramsar Site were concentrated in two focal floodplains, namely, Tirrawarra Swamp and Gidgealpa floodplain (Fig. 1, 4, Table 3). Both areas had increased the number of wells and associated infrastructure of well pads, roads and storages since 1985 (when imagery was available; Fig. 4, Table 3). There were also wells and their infrastructure scattered elsewhere throughout the floodplains of the Ramsar-listed area (Fig. 2, Table 3). In addition, the Cooper Creek–Wilson River floodplain confluence, a wetland system of national importance (Fig. 1, Table S1), underwent rapid development of oil and gas production infrastructure after 1985 (Fig. 3, Table 3).

There was limited publicly available satellite imagery at high resolution (i.e. Sentinel satellite imagery, only available from 2015) to identify effects on flooding regimes, given the rarity of flooding in this region and availability of Sentinel satellite imagery only from 2015. However, there was some disruption of a small 2016 flood, by roads and wells on the floodplain, particularly Tirrawarra Swamp in the Coongie Lakes Ramsar Site (Fig. 4, Fig. S2). There is clearly a need to identify the extent that such structures affect flow and flooding regimes wherever there is historical and future infrastructure, both locally and downstream. Given the low gradient of such floodplains and effects of even minor changes to channels (Knighton and Nanson 1994, 2002; Fagan and Nanson 2004), wells, well pads, roads and storages inevitably affect flow and flooding. It is surprising, given the conservation importance of the Coongie Lakes Ramsar Site, that we could not find any rigorous analyses of the impacts of such infrastructure on flow and flooding regimes for this wetland, or elsewhere in the Lake Eyre Basin rivers. The Bioregional Assessment (Holland et al. 2021) asserted that there were ‘negligible impacts’ of historic infrastructure on flood characteristics, on the basis of comparison of satellite imagery for 2000 and 2020 for the Cooper Basin, citing an analysis; however, neither the analysis nor data were available on the identified public data repository. This claim with absence of detailed analyses that could be critically assessed provides little confidence that a thorough analysis was attempted or that different floods were examined with some assessment of potential biotic impacts (Holland et al. 2021).

Current oil and gas production infrastructure on floodplains is already affecting natural flooding (Fig. 4, Fig. S2) and this will be worse with an increasing development of unconventional gas resources over the next 50 years, particularly in the Cooper Basin (Fig. 1, 5). The Cooper Basin is a focus for rapid development with 1000–1500 wells being planned over the next 50 years, with multiple wells (depths of 500–3000 m drilled laterally; Huddlestone-Holmes et al. 2018) on a single well pad (6–8 wells), each 3.5–4 km apart; 2–3-m borrow pits and; ∼5 km of road for each well pad, estimated at a density of 0.125 well pads km⁻² (EHS Support 2018; Holland et al. 2020). The highly concentrated current developments on Tirrawarra Swamp have a well-pad density of ∼4.5 times greater than this (Table 4, Fig. 4), but this may not account for the increased well-pad footprint with 6–8 wells. However, the current development relates primarily to conventional development of oil and gas, whereas the future is likely to be unconventional development of oil and gas resources. There is already considerable growth in development on the Cooper Creek–Wilson River floodplain confluence (Table 3, Fig. 4). A report to the Queensland Government, Department of Natural Resources, Mines and Energy (released through freedom of information) described that activities of oil and gas production would be outside significant flood extents (e.g. 1990) but acknowledged that these areas could still be developed with four single well pads in 16 km² (EHS Support 2018). This inevitably means substantially increased infrastructure on the floodplain (see Table 3, Fig. 4), reflected in the growth of production wells on the floodplain (Fig. 3). Substantial percentages of the floodplains of the Lake Eyre Basin rivers are already under granted or applied licences for oil and gas exploration and production (Table 4, Fig. 5). Clearly, much of this area is under exploration that does not equate to production and development impacts. Assessment is most progressed for the Cooper Basin (Fig. 1). The Australian Government’s assessment of development of the Cooper Basin (part of the Cooper Creek catchment) estimated that 586–7350 km² (up to 5.6%) will be disturbed by roads (5 km per well pad), well pads (up to 4 ha each) and seismic lines (Holland et al. 2021). There may also be surface-water extractions, currently ∼2% of annual flows for Cooper Creek; these were assessed as of ‘low concern’ for the environment by the Australian Government (Holland et al. 2021) and, yet, this may compound environmental impacts to flooding regimes, particularly if increased for oil and gas production (estimated 400 ML year⁻¹, from ground and surface water; Holland et al. 2021). Further, the current infrastructure is affecting vegetation and ecosystem services. For example, direct removal of vegetation by pads and roads increasing over ∼12 years destroyed ∼3 × 10⁶ ha of vegetation and potentially permanently reduced net primary production by 10 Tg across central Canada and the USA, significantly affecting ecosystem services, increasing fragmentation and affecting wildlife (Allred et al. 2015). Increases of invasive plant species can also occur with oil and gas production (Bergquist et al. 2007). For future expansion in the Cooper Basin, there could be 13 800 km² of groundwater dependent ecosystems, 5626 km² of riparian areas and 16 200 km² of wetland affected by future expansion (Hall et al. 2018). There is ‘potential concern’ that up to one-third of wetland areas will be directly affected, with potentially concerning indirect impacts (e.g. increased fragmentation, altered fire regimes) affecting one-third of riparian areas. Direct impacts include infrastructure (e.g. roads), which can exacerbate indirect effects of introduced species, threatened species and habitat loss (Holland et al. 2021). Given the concentration of current wells on floodplains (Fig. 2, 3), much of this will occur on the floodplains of Cooper Creek, resulting in alterations to up to 1613 km² (Holland et al. 2021). Similar impacts are also likely elsewhere in the future in the Diamantina and Georgina River catchments, where licences are in application or granted (Table 4, Fig. 5).

As well as interrupting natural flooding regimes, production of unconventional gas inevitably carries pollution risks, both for local (spills) and global environments (greenhouse-gas emissions). These relate to processes of extraction, as well as infrastructure and transport. The development of unconventional gas resources requires use of hydraulic fracturing (fracking), which can include 4–28 different chemicals (potentially up to 1076) and water (Lefebvre 2017; Mallants et al. 2020), with toxic impacts on fish (Blewett et al. 2017). As a result, the highest risks are of contamination from chemical spills, including from storages, affecting groundwater and surface water (Huddlestone-Holmes et al. 2018; Soeder 2018; Bamberger et al. 2019). In the Cooper Basin, it was estimated that 8–16 ML will be needed for each vertical well and 24 ML for each horizontal well, with 40–60% being recovered as wastewater (Holland et al. 2020), resulting in substantial amounts of polluted wastewaters in storages on the floodplain. In Colorado’s South Platte Alluvial Aquifer, there were 3449 surface spills (generally low volumes and areas) between 2010 and 2014 (Kanno and McCray 2021). Pollution was deemed of ‘potential concern’ in affecting 12% of the Cooper Basin, which could include release of wastewater into a watercourse if other options are not available (Holland et al. 2021). One of the highest risks not mentioned in any government assessments was overflow or over-topping of contaminated water storages built on the floodplain; this can clearly be seen during the 2016 flood of Tirrawarra Swamp (Fig. 4, Fig. S2) and this was only a medium flood (Fig. S1). The hundreds of water storages currently on the floodplain and future storages built with future increased oil and gas production will increase contaminated water spills onto the floodplain, affecting flood-dependent biota and ecosystem services. Large pastoral areas on the floodplain are marketed and managed for the production of organic beef, without use of chemicals (Brook 2017); increasing spillage of chemicals onto the floodplain could have devastating impacts on this sustainable industry.

There is also the significant issue of fugitive emissions, where greenhouse gases escape from unconventional gas operations; methane is of particular concern given its contribution to global warming (Caulton et al. 2014; Schneising et al. 2014; Bouman et al. 2015; Bista et al. 2017). With increasing development of unconventional gas resources in the Lake Eyre Basin, the emissions profile will inevitably increase (Australian Government Department of Industry 2021), including from underestimation of emissions from gas fields (Neininger et al. 2021), further affecting Australia’s international targets for reduced emissions.

Impacts on floodplains from infrastructure and pollution will be predominantly local but may also affect downstream communities (human and ecological). As well as current and future impacts on the Ramsar-listed Coongie Lakes system and Cooper Creek–Wilson River floodplain confluence, two other wetlands of national importance, the Cooper Creek overflow swamps at Windorah and Nappa Merrie are likely to experience medium to high impacts (Fig. 1, Table S1). Downstream systems such as Lake Yamma Yamma and Lake Cuddapan on Cooper Creek and within the Cooper Basin may also be affected, although the risk may be low (Fig. 1, Table S1). There was no specific reference to such impacts in the government bioregional assessment (Holland et al. 2021) or in current policy or management relevant to the Lake Eyre Basin rivers. There are also many largely unknown potential impacts on ecosystem services, including cultural heritage, fishing, grazing and tourism. There is a need to adequately consider the long-term impacts of such developments in the Lake Eyre Basin river system. Further, there should be a focus and requirement on restoration of the floodplains once oil and gas production is completed, including ensuring that any contamination is removed and natural flow and flooding paths are restored.

The many different policies and legislative instruments (Table 1) focused on protecting the rivers of the Lake Eyre Basin have not adequately protected the natural variability of flows and flooding from oil and gas production infrastructure, as committed to by governments under the Lake Eyre Basin Agreement. Even for the more-protected site of the Ramsar-listed Coongie Lakes, there is little evidence of analyses of impacts or pollution effects from spills, despite the concentrated oil and gas production infrastructure in many areas (Fig. 2, 4). The major governments of the Lake Eyre Basin, namely, the Australian, Northern Territory, Queensland and South Australian Governments, have identified the importance of this river system over more than two decades, primarily through the establishment of the Lake Eyre Basin Agreement, focused on protecting the variability of flows and the dependent biodiversity and cultural values (Table 1). The community and governments raised significant objections to the development of the rivers for irrigation, which would divert flows from downstream floodplains (Gorringe 2017; Kingsford et al. 2017b; Morrish 2017). In particular, concern by the South Australian government about the potential impact of a cotton irrigation development on Cooper Creek, affecting flows to floodplains and the Coongie Lakes Ramsar Site, were a significant driver for the Lake Eyre Basin Agreement (Kingsford et al. 1998, 2017b). Subsequent development of policies, community and government programs and stakeholder groups provided a key focus of the protection of flows to the floodplain rivers of the Lake Eyre Basin (Table 1) (Kingsford et al. 2017b; Tan 2017).

Contrastingly, the focus on the potential impacts of oil and gas infrastructure on the floodplains was largely ignored by these processes. Exacerbating this lack of focus, there was no comprehensive analyses of the level or distribution of this threat across the floodplains and Ramsar-listed Sites. At the same time that the South Australian Government was concerned about the impacts of irrigation upstream, there was relatively little attention on the potential impacts of oil and gas infrastructure on the floodplains of the Coongie Lakes Ramsar Site. In South Australia, there was a 10-year moratorium on hydraulic fracturing over the south-east of the state, in the more populous regions, unlike the Lake Eyre Basin, which is remote and not receiving public concerns. The Queensland Government has attempted to protect their Lake Eyre Basin River floodplain, but pressure from resource development has effectively removed the essential protections. Under the degazetted Wild Rivers legislation, there was an attempt to protect the extent of floodplains, through the specification of Special Floodplain Management Areas, but these were not protected from oil and gas exploration and production (Table 1). A scientific review commissioned by the Queensland Government (Table 1, Fielder et al. 2019) pointed to all of the risks of oil and gas production identified on the floodplains and their dependent biota, including effects of spillages from storages on the floodplains of the Lake Eyre Basin, but this report was not released publicly. This underlines low government commitment to tackling this problem. Despite subsequent commitments by Queensland Governments (Table 1), no subsequent policies and regulations exist to protect these areas and their surface flows. Currently, resource development policies are primarily driving a significant oil and gas production in these areas, with unknown long-term detrimental impacts. Despite the operation of the EPBC Act since 1999 and requirements that potential impacts on Ramsar wetlands be referred, there were only eight referrals listed, with all but one deemed not to be controlled actions requiring rigorous environmental assessment (Table S3). Also, there are well recognised weaknesses in dealing with the effects of cumulative impacts from oil and gas production in terms of environmental assessment (Comino et al. 2014). The development has largely occurred in remote areas, with relatively little scrutiny about the impacts of this development and the likely scenarios for the future. Clearly, there is considerable future potential for increasing damage to these internationally important river systems, including the Coongie Lakes Ramsar Site, with impacts on hydrological connectivity, pollution, as well contributions to greenhouse-gas emissions. There are important issues of procedural justice and social licence in relation to these impacts and effects on the environments, ecosystem services and First Nations people (Luke et al. 2018).

There are many uncertainties and potentially high risks to the rivers of the Lake Eyre Basin and their floodplains, including their biodiversity and cultural values, as well as ecosystem services, resulting from current and future oil and gas exploration and development. The footprint of the oil and gas industry on the floodplains already raises serious issues about impacts on the ecological integrity and connectivity of these unique ecosystems and their biota, which have largely not been addressed by governments. Some of the risks were raised in the bioregional assessment for the Cooper region (Holland et al. 2021), but were largely dismissed as unimportant, with inadequate publicly accessible data and limited analysis. There is a need for more rigorous analyses of the impacts on flooding by structures already built on the floodplains, including well pads, roads and storages. This could be undertaken through rigorous analyses of satellite imagery or more detailed drone analyses coinciding with flooding. In addition, there needs to be independent analysis and reporting of pollution effects, specifically spills, including overtopping of the hundreds of storages on the floodplain holding co-produced water and a monitoring of fugitive greenhouse gas emissions. Effects of these threats on dependent biota remain largely ignored and require a strong focus on assessment as a requirement of current and future developments. There is also a need to implement policies that avoid such high risks on floodplains for all future oil and gas exploration and development. There is increasing understanding that unconventional gas development, including associated infrastructure, is a significant disruptor of floodplain ecosystems, fragmenting their patterns of connectivity and ecological processes. In particular, the Queensland and South Australian Governments need to adequately meet their obligations for protection of these internationally important ecosystems for future sustainability of the economies and ecosystem services of the Lake Eyre Basin. The Australian Government also needs to meet its responsibilities in relation to protecting the Coongie Lakes Ramsar site, protection of other nationally important wetlands and meeting the intent and policies in the Lake Eyre Basin Intergovernmental Agreement.

Supplementary material is available online.

All data were obtained from government online databases, with links to similarly available floodplain extent data from government data and stored on Figshare (Walburn and Kingsford 2022).

R. T. Kingsford was a member of the Lake Eyre Basin Scientific Advisory Panel until 2020, under the governance of the Lake Eyre Basin. The authors declare no other conflicts of interest.

This study was supported primarily by the Centre for Ecosystem Science, UNSW Sydney, and an Australian Research Council Linkage Project (LP180100159), with some funding from The Pew Charitable Trusts.