Letteratura scientifica selezionata sul tema "Aquifers - New South Wales - Kempsey"

Groundwater and surface water have traditionally been managed separately in New South Wales (NSW). However, where rivers and aquifers are hydraulically connected, groundwater pumping has the potential to deplete streamflow. To highlight the major areas of connection in inland NSW, major streams were overlaid with groundwater depth data and the locations of irrigation bores. A consistent pattern was revealed related to basin geomorphology. The main areas of connection are the mid-sections of the major rivers where alluvial systems are well developed yet still narrow and constricted and groundwater depths are shallow. The mapping was validated and the processes explored by calculating water balances for a connected and disconnected reach in the Murrumbidgee River. These showed that, in highly connected reaches, river losses and/or gains are closely related to groundwater levels.

The Australian Candonidae ostracod fauna has few surface water representatives, despite Australia being one of the principal centers of Candonidae biodiversity. The majority of Australian species live in subterranean waters, with most genera and one tribe being endemic to the continent. Species in Australia show Tethyan and Gondwana connections, with relatives living in European and Central/South American subterranean waters. I describe Hancockcandonopsis gen. nov. from boreholes in the alluvial aquifers of the Peel River and Hunter Valley, which at present contains five species, of which three are named, H. inachos sp. nov., H. io sp. nov., and H. tamworthi sp. nov., and two are left on the open nomenclature. All species are allopatric and short range endemics. The genus belongs to the almost cosmopolitan Candonopsini tribe, and the major generic autapomorphy is a hook-shaped h3-seta on the cleaning leg. Characters on the prehensile palps and hemipenis of Hancockcandonopsis indicate a close relationship with the Queensland genus Pioneercandonopsis Karanovic, 2005 and two West Indies genera, Cubacandona Danielopol, 1978 and Caribecandona Broodbaker, 1983. A cladistic analysis, based on 32 Candonopsini species and 24 morphological characters, is used to test phylogenetic relationships among Candonopsini genera globally. Several hypotheses about the historical biogeography of this tribe are discussed.

Through the use of mitochondrial DNA (ATP8 gene), the prediction of intermediate genetic structuring was investigated in two species of estuarine glassfish (Ambassis marianus and Ambassis jacksoniensis) (Perciformes : Ambassidae) to determine the possibility of a generalised ‘estuarine’ genetic structure. Individuals were collected from estuaries in eastern Australia between Tin Can Bay (Queensland) in the north and Kempsey (New South Wales) in the south. Analysis of the haplotype frequencies found in this region suggested panmictic populations with star-like phylogenies with extremely high levels of genetic diversity, but with no correlation between geographic distance and genetic distance. Non-significant FST and ΦST suggested extensive dispersal among estuaries. However, Tajima’s D and Fu’s FS values suggest ‘mutation–genetic drift equilibrium’ has not been reached, and that population expansions occurring 262 000 (A. marianus) and 300 000 (A. jacksoniensis) years ago may obscure any phylogeographic structuring or isolation by distance. The finding of panmixia was contrary to the prediction of genetic structuring intermediate between that of marine fish (shallowly structured) and freshwater fish (highly structured), suggesting high dispersal capabilities in these species.

Groundwater is essential to crop production in many parts of the world, and the provision of clean groundwater is dependent on healthy groundwater ecosystems. To understand better the functioning of groundwater ecosystems, it is necessary to understand how the biota responds to environmental factors, and so distinguish natural variation from human induced changes. This study compares the groundwater biota of the adjacent Gwydir and Namoi River alluvial aquifers, both in the heartland of Australia’s cotton industry, and investigates the relative importance of environmental, anthropogenic, geological, and evolutionary processes on biotic distribution. Distinct differences in biotic assemblages were recorded between catchments at a community level. However, at a functional level (e.g. microbial activity, stygofauna abundances and richness) both ecosystems were similar. The distribution of biota in both catchments was influenced by similar environmental variables (e.g. geology, carbon availability, season, and land use). Broad trends in biotic distribution were evident: stygofauna responded most strongly to geological variables (reflecting habitat) and microbes to water quality and flow. Agricultural activities influenced biota in both catchments. Although possessing different taxa, the groundwater ecosystems of the two aquifers were functionally similar and responded to similar environmental conditions.

The present study examined the water relations of wallum dry sclerophyll woodland on the lower north coast of New South Wales (NSW). Wallum is the regionally distinct vegetation of Quaternary dunefields and beach ridge plains along the eastern coast of Australia. Wallum sand masses contain large aquifers, and previous studies have suggested that many of the plant species may be groundwater dependent. However, the extent of this dependency is largely unknown, despite an increasing reliance on the aquifers for groundwater extraction. Fifteen species from five growth-form categories and seven plant families were investigated. The pre-dawn and midday xylem water potential (ψx) of all species was monitored over a 20-month period from December 2007 to July 2009. Pressure–volume curve traits were determined for each species in late autumn 2008, including the osmotic potential at full (π100) and zero (π0) turgor, and bulk modulus of elasticity (ε). Carbon isotope ratios (δ13C) were determined in mid-autumn 2008 to measure water use efficiency (WUE). Comparative differences in water relations could be loosely related to growth forms. A tree (Eucalyptus racemosa subsp. racemosa) and most large shrubs had low midday ψx, π100 and π0, and high ε and WUE; whereas the majority of small and medium shrubs had high midday ψx, π100 and π0, and low ε and WUE. However, some species of similar growth form displayed contrasting behaviour in their water relations (e.g. the herbs Caustis recurvata var. recurvata and Hypolaena fastigiata), and such differences require further investigation. The results suggest that E. racemosa subsp. racemosa is likely to be groundwater dependent, and large shrubs such as Banksia aemula may also utilise groundwater. Both species are widespread in wallum, and therefore have the potential to play a key role in monitoring ecosystem health where aquifers are subject to groundwater extraction.

The management of water resources across Australia is undergoing fundamental reform in line with the priorities identified by the Council of Australian Governments (COAG) in 1994. This includes reforms to the specification of property rights, the way the resource is shared between the environment, irrigators and other users, charges for water use and the operational management of the river systems. In New South Wales (NSW), a series of water sharing plans (WSPs) is being developed for each water source in the State including regulated rivers, unregulated rivers and groundwater aquifers. These plans, which are the mechanisms by which COAG reforms are being implemented, are being developed by community-based water management committees (WMCs). The role of the WMCs is to develop a plan that achieves a balance between environmental, economic and social outcomes. NSW Agriculture has assisted a number of WMCs by quantifying the economic impact of proposed WSP options on the irrigation community. This paper outlines the approach taken by NSW Agriculture to quantifying economic impacts on irrigators in regulated catchments and provides results of case studies in the Lachlan River Catchment which is heavily developed for irrigation.

Short-range endemism is common in groundwater fauna (stygofauna), placing many species at risk from anthropogenic impacts such as water abstraction and pollution. Few of the alluvial aquifers in eastern Australia have been sampled for stygofauna. Fauna from two aquifers in Queensland and two in New South Wales was sampled to improve ecological knowledge of stygofauna and the potential threats posed to it by development. Our surveys found stygofauna in all four aquifers, with most taxa collected from bores with low electrical conductivity (<1500 µS cm–1). Taxon richness decreased with distance below the water table. The most taxon-rich bores in each region occurred where the water table depth was <10 m, were associated with the alluvium of tributaries of large regulated river systems, and were near phreatophytic trees. It is possible that tree roots constitute a habitat and source of organic matter in alluvial aquifers as they do in cave streams. It is important to document the biodiversity of particular regions and aquifers so that species can be conserved in the face of increasing groundwater use. For effective resource management, future research should strive to understand the tolerances and ecological requirements of groundwater communities and the ecosystem services they provide.

The eastern Australian aquifers remain mostly unexplored; however, recent surveys suggest that there could be substantial levels of subterranean biodiversity hidden in these aquifers. Groundwater fauna (stygofauna) is often characterised by short-range endemism. Furthermore, high levels of cryptic species, and lack of formal taxonomic descriptions and taxonomic expertise for many of the groups demand innovative approaches for assessing subterranean biodiversity. Here we evaluate the potential of using DNA barcoding as a rapid biodiversity assessment tool for the subterranean groundwater fauna of New South Wales, Australia. We experienced low amplification success using universal and more taxon-specific primers for PCR amplification of the barcoding gene (COI) in a range of crustacean stygofauna. Sequence comparisons of the most commonly used COI universal primers in selected crustacean taxa revealed high levels of variability. Our results suggest that successful amplification of the COI region from crustacean stygofauna is not straightforward using the standard ‘universal’ primers. We propose that the development of a multiprimer (taxon specific) and multigene approach for DNA barcode analyses, using next-generation sequencing methodologies, will help to overcome many of the technical problems reported here and provide a basis for using DNA barcoding for rapid biodiversity assessments of subterranean aquatic ecosystems.

Elevated arsenic concentrations have been reported in a drinking water and irrigation-supply aquifer of Stuarts Point, New South Wales, Australia. Arsenic occurrence in such aquifers is potentially a major issue due to their common use for high yield domestic and irrigation water supplies. Ten multi-level piezometers were installed to depths of approximately 30 m in the sand and clay aquifer. Sediment samples were collected at specific depths during drilling and analysed for chemical and mineralogical composition, grain size characteristics, potential for arsenic release from solid phase and detailed microscopic features. From this data, a full geomorphic reconstruction allowed the determination of source provenance for the aquifer sediments. The model proposed herein provides evidence that the bulk of the aquifer was deposited under intermittent fluvial and estuarine conditions; and that all sediments derive from the regional arsenicmineralised hinterland. More than 200 groundwater samples were collected and analysed for over 50 variables. The heterogeneity of the aquifer sediments causes redox stratification to occur, which in turn governs arsenic mobility in the groundwater. The bulk of the aquifer is composed of fluvial sand deposits undergoing reductive dissolution of iron oxides. Arsenic adsorbed to iron oxide minerals is released during dissolution but re-adsorbs to other iron oxides present in this part of the aquifer. The deeper, more reducing fluvial sand and estuarine clay groundwaters have undergone complete reductive dissolution of iron oxides resulting in the subsequent mobilisation of arsenic into groundwater. Some of this arsenic has been incorporated into iron sulfide mineral precipitates, forming current arsenian pyrite sinks within the aquifer. The extraction of groundwater from the aquifer for irrigation and drinking water supply induces seawater intrusion of arsenic-rich estuarine water, bringing further dissolved arsenic into the aquifer. A greater understanding of the source, sinks and mobilisation of arsenic in this aquifer contributes to our broad understanding of arsenic in the environment; and allows aquifer specific management procedures and research recommendations to be made. Any coastal or unconsolidated aquifer that has sediments derived from mineralised provenances should consider monitoring for arsenic, and other potentially toxic trace elements, in their groundwater systems.

Arsenic (As) in groundwater systems is a problem in many parts of the world owing to ever-increasing extraction of groundwater resources to meet the needs of growing populations. Surprisingly, the occurrence of elevated As concentrations in coastal sandy aquifers has only recently been published as a result of this research. Sandy aquifers are commonly used as a clean and reliable source of water for domestic, agricultural and industrial needs due to their high recharge rates and the filtering capacity of sands. Water quality monitoring in Australian sandy aquifers is usually limited to a small suite of major elements and salinity measurements to determine the quality of groundwater and to identify any potential problems from seawater intrusion as a result of over extraction. Minor and trace elements, particularly toxic elements, have largely been ignored in regular monitoring programs. Prompted by an emerging pattern of human health problems in a community reliant on groundwater, hydrogeochemical investigations of the Stuarts Point coastal sand aquifer, on the North Coast of New South Wales, Australia, identified elevated As concentrations of up to 337 ????g/L in the catchment's Pleistocene barrier sands. These concentrations are well in excess of the World Health Organisation and the Australian National Health and Medical Research Council water quality criteria of 10 and 7 ????g/L respectively. From research into the Stuarts Point geology, geochemistry, geomorphology, hydrogeology and hydrogeochemistry, and with the assistance of environmental isotopes, the spatial distribution, occurrence and mobilisation processes of As were determined. The presence and distribution of elevated As concentrations in the regional coastal aquifer system are sporadic and involve a series of complex hydrogeochemical processes. No single hydrogeochemical process can describe the release of As from solid phase to groundwater system on the regional scale. Processes of competitive exchange with PO43- and HCO3-, reductive dissolution of Fe oxyhydroxides and arsenical pyrite oxidation, though not forming dominant correlations, are still evident and influence As chemistry at this scale. Detailed investigations of the hydrogeochemistry on the vertical scale have identified two main processes as causing As to be released and mobilised. The first process is associated with the oxidation of arsenical pyrite in Acid Sulphate Soils and metal hydrolysis reactions which mobilise As in the acidic environment. In the absence of dissolved oxygen (DO), NO3- acts as the oxyanion facilitating arsenical pyrite oxidation and releasing As into solution. The second process that mobilises As from the sediments is the liberation of As from metal-oxyhydroxides in the carbon-rich environment, where HCO3- originates from the dissolution of shell material in the Pleistocene barrier sands. The marine influenced depositional history and geomorphology of the aquifer provide opportunities for As to become incorporated into the aquifers matrix in a variety of mineral forms, which is an occurrence not considered to be unique to the Stuarts Point catchment. The findings presented here are amongst the first detailed studies of naturally occurring As in an Australian groundwater system as well as in the Pleistocene coastal sand aquifer environment. The understanding of As accumulation and mobilisation identified as a result of this research emphasises the need for potential As occurrences in similar groundwater systems in other coastal environments in Australia, and globally, to be considered.