Over the past three years the Department for Environment and Water (DEWNR), in collaboration with FOMS and others, has been conducting the Desert Jewels project aimed at improved management of mound springs to achieve conservation objectives. A primary area of interest has been the management of reeds (Phragmites), which have tended to proliferate in springs fenced to exclude stock. While Phragmites is a natural component in the landscape in mound spring country, it is thought that many decades of cattle intrusion into the mound springs has elevated nutrient levels and, when stock are excluded from the springs, the elevated nutrients have favoured prolific regrowth of Phragmites at the expense of other vegetation. It has been postulated that burning of the Phragmites, possibly in line with traditional Aboriginal burning practices, might be a useful management tool to help restore a more diverse vegetation cover at these springs. The burning process may help to hasten a decline in nutrient levels in these springs.
Phragmites burning strongly at Bopeechee Spring. To provide some scale, Dean Stuart can just be discerned on the right-hand side (photo: Bruce Gotch)
With this in mind, DEWNR collaborated with the local Arabana people and with FOMS personnel in June 2016 to burn two Phragmites springs on Finniss Springs (Bopeechee Spring and a spring described as HBO004). A trial burn was also conducted at nearby Beatrice spring – a spring with bulrush (Typha) cover rather than Phragmites. Also participating was Dr Jasmin Packer, Postdoctoral Fellow, School of Biological Sciences, University of Adelaide. Dr Packer is working on a project on Phragmites management at a national and international scale and is keen to integrate the information from the mound spring burning trials into her own project.
Despite the regular and sometimes heavy rainfall in the Far North during 2016, the burning of Phragmites at Bopeechee and HBO004 springs was very successful burning virtually all above-ground or above-water vegetation and leaving a thick mat of ash.
The burning of the Typha spring (Beatrice) was less successful. The Typha was quite green and only a partial burn was possible. In the last week of July 2016 FOMS members Colin Harris, Bruce Gotch, Claire Bockner and Simon Lewis, along with Arabana elder Dean Stuart, paid another visit to Beatrice, Bopeechee and HBO004 springs. The group was interested to note quite prolific regrowth of Phragmites at Bopeechee and HBO004 just six weeks after the burns – with up to 70 Phragmites stems per square metre up to 0.65m high. The group repeated a number of one metre square quadrats at these springs to measure the extent of regrowth.
It is intended that monitoring will continue at these springs for several years to assess the longer term response of the reeds and of other vegetation associated with the springs. This will link in with monitoring at other springs – such as Outside and the Fountain, on the Peake – where the Phragmites appears to be in a state of natural decline. Another aspect to be considered is whether repeated burning at a particular spring – rather than a single one-off burn – should be trialled as a management option.
In the early 1980s, the State Environment agency commissioned studies to document the features and importance of mound springs in South Australia. Eleven springs were identified as being of particular significance and were fenced by the Department in the period 1984 to 1988. These springs were Blanche Cup, the Bubbler, Coward Spring (all now within Wabma Kadarbu Mound Springs Conservation Park), Strangways Spring (on Anna Creek), Tarlton, Outside, Twelve Mile, Fountain and Big Perry springs (all on the Peake Pastoral Lease), Nilpinna Spring on Nilpinna Pastoral Lease and Big Cadna-Owie Spring on Allandale Pastoral Lease. The Department monitored the condition of these fenced springs from 1984 to 2005. With the exception of occasional fence repairs by Peake station personnel at Twelve Mile and some work to strengthen weak points and install bayonet gates in the early 1990s, the fencing has not been actively maintained. It has lasted well, but is now at a stage where attention is needed.
Maintenance and repair work on the fencing around those springs outside of Wabma Kadarbu Mound Springs Conservation Park was one of the main tasks for FOMS volunteers in their trip to the springs in late July 2016. The fenced spring at Strangways did not require attention as this is within the much larger area at Strangways fenced by S Kidman and Co in the mid-1990s. The fencing group in the July 2016 trip comprised Brenton Arnold and Brendan Lay, with support from Bruce Gotch, Bernice Cohen, Colin Harris, Simon Lewis, Elizabeth Lay, Claire Bockner and Arabana elder Dean Stuart. Brenton, still in recovery from a bout of the ‘flu, brought with him a trailer load of fencing materials from Port Augusta.
The most arduous fencing work was at Twelve Mile Spring, where there have been problems in the past with cattle breaching a weak section of fence and gaining access to the springs. There, a section of fence needed to be realigned to avoid the vulnerable section.
Significant fence work was also needed at the Fountain. Here the spring tail passes through the fence and the fence has become weakened as a result of cattle pugging and eroding the wetland area just outside the fence. Brenton and Bren reinforced this section with star-droppers and additional wiring. At nearby Outside Spring one section of fence needed re-straining.
After completing the fencing work on the Peake, the group moved on to Nilpinna Spring, on Nilpinna Station. It was expected that significant repair work might be needed here as the spring area had been burnt three to four years ago – in an attempt to control bamboo growing at the spring – and this burn had damaged part of the fence. However, the singed fence-posts were in reasonable condition, so the task was not quite as great as anticipated. Vegetation was cleared away from the damaged section, the fence was re-strained and a number of spacers replaced.
Dean Stuart and Bruce Gotch check the bayonet gate at Twelve Mile Spring
Bayonet gates at each of the above springs were also serviced, with Bruce Gotch taking charge of this work. The bayonet gates were installed in the early 1990s after a particular problem with cattle gaining access through the fence to the Fountain. The design of the bayonet gates is such that cattle cannot get through them from outside but can get through them from inside the fenced area: thus if cattle do gain access through the fence in some way, they do have an opportunity to exit the fenced area via the bayonet gate.
While the above work may secure the fenced springs for the next few years, FOMS is concerned that ongoing reliance on volunteers to maintain the fencing is not necessarily the best option. FOMS will be promoting discussions aimed at looking at other partnership approaches that may provide better security for these areas into the longer term.
One of the springs at Levi to be protected in the proposed enclosure
As part of DEWNR’s Desert Jewels project, it is proposed that a number of springs at Levi Springs, on Peake Pastoral Lease, be fenced to provide protection from stock. In August 2015, a combined group from FOMS and DEWNR inspected Levi Springs and plotted a proposed fence alignment that would include all of the springs at Levi and most of the associated rock formations. In early 2016, DEWNR’s Sam Gitahi, then Project Officer for the Desert Jewels Project, re-visited Levi with representatives of the Arabana people to check the acceptability of the proposed fence alignment to the Arabana community.
Subsequently, the proposal was considered by the Directors’ Group of the Arabana Aboriginal Corporation, which decided not to support the proposed alignment. The Directors’ Group indicated that a modified fencing alignment, taking in the springs but not the main associated rock formations, might be acceptable.
Accordingly, in the July 2016 trip FOMS volunteers returned to Levi Springs to review the situation. Arabana elder Dean Stuart accompanied the group. Along with Dean the FOMS group comprised Colin Harris, Elizabeth Lay, Bernice Cohen, Claire Bockner and Simon Lewis.
These ruins of a shepherd’s hut will also be included in the fenced area
An agreed alignment was readily identified, taking in several springs on the northern side of the main rock formations, as well as the ruins of the former shepherd’s hut nearby. Peake manager Jim Wheeler met the group at Levi Springs and foreshadowed no particular concerns from the Kidman perspective in relation to the fencing. Following the field inspection of July 2016, the Directors of the Arabana Aboriginal Corporation met in Marree on 20 August and endorsed the revised fence alignment. Pastoral lessees S. Kidman and Co have also given the go-ahead.
Materials for the originally proposed fence alignment have already been purchased by DEWNR and this Department and FOMS are now in discussion about arrangements for erection of the fence. This work will provide protection for an important area of springs and, as such, will be a significant milestone for the Desert Jewels project.
As can be seen from the photo, the spring has a fairly uniform coverage of low sedges, in this case the bore-drain sedge Cyperus laevigatus. There are currently no reeds, Phragmites, at the site.
The Desert Jewels project conducted by the Department for Environment and Water (DEWNR) covers many aspects of mound springs management, some of which are described in other items in this newsletter. One particular area of interest is the effect of controlled or pulse grazing on mound springs. Following consultation between DEWNR and FOMS personnel and Colin Greenfield at Billa Kalina Station, a spring is to be fenced on Billa Kalina in a configuration that will allow controlled grazing in part of the fenced area and complete exclusion of stock in another section. Another part of the spring wetland will be permanently open to grazing so, in effect, there will be three management regimes to monitor at the spring.
During FOMS’ trip to the mound springs in July 2016. Brendan and Elizabeth Lay and Bernice Cohen visited Billa Kalina. They met with Colin Greenfield to discuss arrangements for the fencing, then drove on to the spring to be fenced to check the alignment for the fencing and to collect baseline vegetation data. The data will provide a useful comparison for future measurements when the fencing is in place.
Ongoing consultation with Colin Greenfield will be needed to keep records of grazing patterns around the spring and within the exclosure which will be stocked from time to time.
As can be seen from the photo, the spring has a fairly uniform coverage of low sedges, in this case the bore-drain sedge Cyperus laevigatus. There are currently no reeds, Phragmites, at the site.
Bulrushes and sedges in good condition at Milne Springs
During the July 2016 FOMS trip a number of observations were made of the condition of wetland vegetation at many springs. This included photo-point monitoring at springs fenced by the State Environment agency during the 1980s – Outside, Twelve Mile, Fountain and Big Perry Springs on the Peake, Nilpinna Spring on Nilpinna Station and Big Cadna-Owie Spring on Allandale Station. The State Environment Department conducted annual photo-point monitoring at these and several other springs from the mid-1980s until 2005.
But first there are some general observations that can be made. 2016 has been a stand-out year with regular and plentiful rain in the Far North of the State. One of the results of this type of year is that surface waters become widespread and stock fan out to a greater degree across the landscape. So, whereas in dry times stock will often have heavy impact on unprotected mound springs, in good wet seasons the springs are less impacted and the spring vegetation has an opportunity to recover. As an example, the photo below – taken in July 2016 – shows Milne Springs, on the Peake, with a good cover of predominantly Typha (bulrush) and Cyperus laevigatus (bore-drain sedge). Milne Springs are open to grazing by stock.
The photo-point monitoring repeated on the July 2016 trip for the first time since 2005 highlighted two main points.
Firstly, it highlighted that reeds (Phragmites) have been steadily increasing in distribution and abundance at several springs following the fencing of about 30 years ago. The following two photos, taken from a similar location at the Fountain Spring, highlight this point. In 2001, Phragmites was largely restricted to the spring vent (in background of photo). By 2016 Phragmites had taken over the lower section of the spring tail (foreground of photo).
The second observation is that there are signs that Phragmites may have “peaked” at a couple of protected springs. This is most evident at Outside Spring where the area of the main vent now has semi-open water, as shown in the photo below.
This observation sits quite well with the hypothesis that the proliferation of Phragmites in springs following fencing and stock exclusion is boosted by elevated nutrient levels at these springs following decades of stock access. With prolonged stock exclusion, nutrient levels may decline slowly and this may affect the vigour and distribution of Phragmites. A lesser decline of this nature has been observed at the Fountain and it may be that the intrusion of cattle into the Fountain in the early 1990s means that the Fountain is trailing Outside Springs in terms of nutrient reduction.
Research being undertaken by the University of Adelaide includes nutrient analyses in the springs and this may help to clarify whether the above hypothesis is valid.
Colin Harris, Bernice Cohen and FOMS colleagues inspect prolific Phragmites growth at the Fountain.
Members may recall that the Department for Environment and Water (DEWNR) initiated a project in mid-2013 to develop clearer ideas about the management of mound springs in South Australia. This project – over three years and funded through a $1million Commonwealth Government grant – is known as the Desert Jewels Project and FOMS has been a partner throughout. The project is now in its final year.
A particular interest for FOMS has been the proliferation of reeds (Phragmites) at many springs that have been protected from grazing impacts. This proliferation has been to the apparent detriment of other wetland species and FOMS has been keen to see active management trials undertaken with the aim of restoring greater habitat diversity at springs affected by Phragmites. Two springs – the Fountain on the Peake pastoral lease and Beatrice Spring on Finniss Springs – have been selected for burning trials and DEWNR’s project team has obtained clearance from the local Arabana people for the burns to be undertaken. The Arabana will assist with the trial burns so that they mimic traditional burns as much as possible.
The trial burns at the Fountain and Beatrice were planned for March 2016 but heavy rains in the area during that month have led to their deferment. Weather permitting, the trial burns will take place shortly.
A second focus for FOMS in the Desert Jewels project has been the fencing of additional spring areas. At Billa Kalina Station, a spring will be fenced in a configuration that will allow part of the spring wetland to be grazed by cattle in a controlled manner. Another part of the fenced spring will remain ungrazed to provide a comparison in terms of grazing impacts.
DEWNR has purchased and delivered the required fencing materials and Billa Kalina manager Colin Greenfield will erect the fence.
Fencing of Levi Springs on the Peake is also planned. FOMS originally hoped to fence Levi Springs within one enclosure of about 1.5 square kilometres, in a configuration that would also include the impressive rock formations at this site. However, following an inspection of the site with representatives of the local Arabana people and further consultation with the Arabana Directors’ Group, it has been agreed that fencing will be limited to the springs and their immediate environs.
Canberra-based Dr MA (Rien) Habermehl is an internationally recognised hydrogeologist who has decades of experience in researching the Great Artesian Basin and its associated mound springs. Dr Habermehl is a FOMS member and accompanied the group on its field trip in August 2015. Here Dr Habermehl provides an overview of the GAB and its springs.
Great Artesian Basin map
The Great Artesian Basin is a confined groundwater basin, which underlies arid and semi-arid regions across 1.7 million km2 or one- fifth of Australia. The basin’s groundwater resources were discovered around 1880, and their development allowed the establishment of an important pastoral industry. Pastoral activity, town water supplies, mining and petroleum ventures are all totally dependent on artesian groundwater. The Great Artesian Basin is a multi- layered confined aquifer system, with artesian aquifers in Triassic, Jurassic and Cretaceous continental quartzose sandstones. Intervening confining beds (aquitards) consist of siltstone and mudstone; Cretaceous marine sediments form the main confining unit. The Basin is up to 3000 m thick, and is a large synclinal structure, uplifted and exposed along its eastern margin and tilted southwest.
Recharge occurs in the relative high rainfall eastern margin, and the western margin in the arid centre of the continent receives minor recharge. Regional groundwater movement is towards the southern, southwestern, western and northern margins, where artesian springs discharge and produce carbonate mounds. Average groundwater flow rates in the eastern and western marginal parts range from less than 1 to 5 m/year based on hydraulic data and 14C, 36Cl and 4He measurements. Chlorine-36 and carbon-14 isochrones show residence times from recent to several thousand years near the marginal recharge areas, to more than one million years near the centre of the Basin. Environmental (stable and radio-active) isotopes and hydrochemical studies confirmed the source and origin of artesian groundwater as meteoric water, which recharged from geological to modern times.
Potentiometric surfaces (pressure levels) of the Triassic, Jurassic and Early Cretaceous aquifers are still above ground level, but pressure drawdowns of up to 100 m were recorded from 1880 to the 1990s in some relatively closely developed areas. Artesian groundwater extraction by the pastoral industry and for homestead and town water supplies, which peaked at about 2000 ML/day around 1918, caused this drawdown. About 4700 flowing artesian water bores were drilled in the main Lower Cretaceous-Jurassic aquifers at depths of up to 2000 m, but average 500 m. About 3100 controlled and uncontrolled artesian waterbores remain flowing with an accumulated discharge of 1500 ML/day. About 25000 non-flowing artesian water bores, generally using windmill operated pumps, tap shallower Cretaceous aquifers. Some flowing artesian water bores ceased to flow, necessitating groundwater to be pumped and spring discharges declined, caused by water bore development and resultant lowered artesian pressures in many parts of the basin during the last 130 years and in some areas springs have ceased to flowGroundwater quality of the Lower Cretaceous-Jurassic aquifers is good at 500 to 1500 mg/L total dissolved solids. Groundwater is suitable for domestic, town water supply and stock use, though unsuitable for irrigation in most areas.
The water is of the Na-HCO3-Cl type, and these ions contribute more than 90 % of the total ionic strength of solutes in the main Basin area. In the southwestern part of the Basin the groundwater is characterised by Na-Cl-SO4 type water, and the two regional groundwater flow directions show different hydrochemical characteristics, with westward flowing water being of the Na-HCO3-Cl type and eastward flowing water being of the Na-Cl-SO4 type.
Water quality is better in the lower aquifers than in the higher aquifers in the Lower Cretaceous- Jurassic sequence. Groundwater temperatures at the bore-heads range from 300 to 1000 C, and are a potential geothermal energy source. Spring temperatures range from 200 to 450 C.
Free-flowing open earth bore drain
Prior to the 1960s, artesian water use was mainly for pastoral, homestead and town supplies, but since then the development of petroleum resources in the basin area also used its groundwater. The basin (and underlying rocks) comprises abundant hydrocarbon reservoir (and some source) rocks, and commercial and sub-commercial oil and gas is produced from Jurassic and Cretaceous sandstones, contradicting earlier beliefs that the basin-wide groundwater throughflow had flushed out hydrocarbons. Since the 1980s, mineral mining in and near the basin started using the basin’s artesian groundwater, in particular from the Olympic Dam bore-fields in South Australia and mines in north-western Queensland and north- eastern New South Wales. Present day and future additional oil and gas, mineral mining, coal seam gas and geothermal developments could affect artesian groundwater flow to water bores and springs.
Environmental geology issues relate to the development of the artesian groundwater resources of the Great Artesian Basin and include aspects of sustainable groundwater use and groundwater and rangelands management. Extraction of artesian groundwater during the last 130 years has affected the Basin to varying degrees through large scale drawdowns, which reduced artesian pressures and reduced discharges from artesian water-bores and springs.
The Great Artesian Basin Bore Rehabilitation Program (GABBRP, 1989-1999) and the subsequent Great Artesian Basin Sustainability Initiative (GABSI, 1999-2014) which provides a substantial level of Australian Government and State Government assistance to landholders to rehabilitate flowing artesian bores and replace the open earth bore drains of free-flowing artesian bores with piped water distribution systems throughout the GAB.
Great Artesian Basin Bore Rehabilitation Program
GABSI assists the implementation of the GAB Strategic Management Plan prepared by the Great Artesian Basin Coordinating Committee (GABC 2000). he Plan provides for the restoration of the environmental assets of the Great Artesian Basin with an emphasis on springs (GABC 2000).
Following the implementation of GABSI and rehabilitation of bores and reduction of their outflows, potentiometric surfaces have become stable and increased in some areas and may increase flows from springs. Securing groundwater flows to springs, particularly those with high conservation values, could be an addition to the criteria used to select bores for rehabilitation and piping to maximise opportunities to sustain or re-activate springs. The GABSI program has recently (2015) been extended for a period of three years. These programs aim to rehabilitate waterbores in poor condition and equip bores with control valves. The replacement of the inefficient open earth drain distribution system, which causes up to 95 percent wastage of the water, with a piping system is encouraged. These measures will benefit groundwater and rangeland management.
In addition, the Environment Protection and Biodiversity Act (EPBC) 1999 provides environmental protection for the GAB springs, and is the main regulation tool for larger developments. Groundwater use by the petroleum and mining industries during the last 20 – 35 years affect some parts of the Basin. The South Australian part of the Basin is an example where the combination of groundwater exploitation for the pastoral industry, town and homestead water supplies and petroleum and mining industries impact on the Basin’s groundwater conditions and on the artesian springs, the natural outflow points of the Basin.
The natural flowing artesian springs originating from the Jurassic-Lower Cretaceous aquifers occur throughout the GAB, though mainly in the marginal areas, within twelve large supergroups, including the Barcaldine, Springsure, Bogan River, Bourke, Eulo, Lake Frome, Lake Eyre, Dalhousie, Mulligan River, Springvale, Flinders River and Cape York. Most springs are concentrated in relatively small areas, with rates of discharge of individual springs ranging from less than 1 L/s to about 150 L/s (from a spring at Dalhousie Springs, northern South Australia). Flowing artesian springs within the Basin and in the discharge margins of the Basin are generally associated with structural features, such as faults, folds, monoclines and intersecting lineaments.
Upwards groundwater flow along faults is the source of many springs, as well as the abutment of aquifers against impervious bedrock and pressure water breaking through confining beds near the discharge margins of the Basin. Diffuse discharge occurs from the artesian aquifers near the margins where the overlying confining beds are thin and waterlevels high. Springs are quite common in the recharge areas along the eastern margins, but most of these springs are the result of “overflow” or the “rejection” of recharge into the aquifers, or result from the intersection of the local topography and aquifers. Many springs have built up conical mounds consisting of deposits of clayey and/or sandy sediments and carbonates, which are several metres to several tens of metres in diameter, and up to several metres high. The mounds are formed by deposition of particles brought up from the aquifers and the confining beds, by accumulation of aeolian material and by the chemical and biological precipitation of solids dissolved in the artesian groundwater.
Some mounds consist of mud, but many mounds, particularly those built by springs in the western and southwestern margin of the Great Artesian Basin are built up of carbonates, which are dominated by tufa, travertine and very fine-grained limestone or crystalline carbonate, mainly calcite and dolomite. The carbonates originate from the combined chemical precipitation of calcium carbonate out of the artesian groundwater, and precipitation by algae and bacteria. Terraced mounds and waterfall or cascade deposits produced by algae are common, though most accumulations consist of steeply sloping mounds. These springs are terminal evaporitic systems, usually comprising a central carbonate mound, with outer zones dominated by sulphate and chloride salts. Mound morphology is controlled by several factors, including groundwater discharge rates, hydrochemistry, evaporation, influence of inorganic versus organic carbonate precipitation and local subsidence of the mound.
The natural flowing artesian springs and their spring mound deposits in South Australia are of particular significance and interest as the deposits are geological (and hydrogeological) records because of their fossils of fauna and flora, their ages, and their relationship to wetter and drier times (palaeoclimates) in central and eastern Australia during the last several 100 000s years and changes in groundwater discharges and spring deposits, their Aboriginal and early European history and culture, and the presence of unique flora and fauna.
Artesian springs and their deposits in the Lake Eyre region in the southwestern part of the Basin range from topographically high springs to younger, topographically low springs as a result of the lowering of the land surface and spring outlet levels in Quaternary times (deposits of extinct pre-Quaternary springs occur more than 40 m above the present springs). Fossil carbonate spring deposits of Pleistocene ages, consisting of very fine- grained carbonates with abundant reed casts, gastropod shells and algal structures, rise several tens of metres above the present land surface where the present active springs (and Recent spring deposits) occur. The higher, older spring carbonates cap circular mesas and hills and overlie pedestals of Cretaceous mudstones (Hamilton Hill, Beresford Hill and Strangways Springs).
This also indicates that the potentiometric surface in the Lake Eyre region has declined considerably during recent geological time. Morphological diversity and lithofacies patterns indicate that the spring complexes have developed over several climatic cycles. The dated ages of spring deposits range up to 740 000 ±120 000 years, with some spring deposits probably being older. The ages of several basal spring deposits, as determined from thermoluminescence, 14C, U/Th and palaeomagnetic studies suggest that some springs might have been (re-) activated as a result of major climatic changes.
An increased awareness and understanding of the springs and environmental aspects since the 1980s has helped to preserve the springs, despite increased groundwater development by pastoral and resources industries and increased tourism and visitor numbers, and through the creation of the Witjira (Dalhousie Springs) National Park and the Wabma Kadarbu Mound Springs Conservation Park.
The provision of access to some good examples of springs in these Parks, fencing and explanatory signs and other guidance, has and should offer regulated access and limit environmental damage to the accessible springs and to other springs within fenced areas. The cooperation between landholders with springs on their properties and government authorities has resulted in successful management, though further activities, including fencing, should be undertaken to exclude grazing and trampling by livestock and feral animals.
A large number of scientific studies on the springs, by Australian Government and State Government organisations, universities and resources industries, as well as long term monitoring of their flora and fauna, environmental aspects, nature and origin, including the deposition and composition of the spring mound sediments, their ages and the groundwater flow and hydrochemistry, has significantly increased knowledge about the springs since the 1980s, though continuing monitoring and additional studies should be carried out.
Potentiometric surfaces (pressure levels) of the Triassic, Jurassic and Early Cretaceous aquifers are still above ground level, but pressure drawdowns of up to 100 m were recorded from 1880 to the 1990s in some relatively closely developed areas. Artesian groundwater extraction by the pastoral industry and for homestead and town water supplies, which peaked at about 2000 ML/day around 1918, caused this drawdown. About 4700 flowing artesian water bores were drilled in the main Lower Cretaceous-Jurassic aquifers at depths of up to 2000 m, but average 500 m. About 3100 controlled and uncontrolled artesian waterbores remain flowing with an accumulated discharge of 1500 ML/day. About 25000 non-flowing artesian water bores, generally using windmill operated pumps, tap shallower Cretaceous aquifers. Some flowing artesian water bores ceased to flow, necessitating groundwater to be pumped and spring discharges declined, caused by water bore development and resultant lowered artesian pressures in many parts of the basin during the last 130 years and in some areas springs have ceased to flowGroundwater quality of the Lower Cretaceous-Jurassic aquifers is good at 500 to 1500 mg/L total dissolved solids. Groundwater is suitable for domestic, town water supply and stock use, though unsuitable for irrigation in most areas.
