Dissertations / Theses: 'Hydrology – Australia'

1

Wischusen, John David Henry School of Biological Earth &amp Environmental Sciences UNSW. "Hydrogeology, hydrochemistry and isotope hydrology of Palm Valley, Central Australia." Awarded by:University of New South Wales. School of Biological, Earth and Environmental Sciences, 2005. http://handle.unsw.edu.au/1959.4/32925.

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The Palm Valley oasis in arid central Australia is characterised by stands of palm trees (Livistona mariae). How these unique plants, separated by nearly a 1000 kilometres of arid country from their nearest relatives persist, has long fascinated visitors. Defining the hydrogeology of the Hermannsburg Sandstone, a regionally extensive and thick Devonian sequence of the Amadeus Basin that underlies Palm Valley, is the major thrust of investigation. Appraisal of drilling data shows this aquifer to be a dual porosity fractured rock aquifer which, on a regional scale, behaves as a low permeability, hydraulically continuous resource. Groundwater is low salinity (TDS <1000 mg/L) and bicarbonate rich. Slight variations in cation chemistry indicate different flow paths with separate geochemical histories have been sampled. Stable isotope (????H, ???????O) results from Palm Valley show groundwater to have a uniform composition that plots on or near a local meteoric water line. Radiocarbon results are observed to vary from effectively dead (< 4%) to 87 % modern carbon. To resolve groundwater age beyond the radiocarbon window the long lived radioisotope 36Cl was also used. Ratios of 36Cl/Cl range from 130 to 290 x 10-15. In this region atmospheric 36Cl/Cl ratio is around 300 x 10-15. Thus an age range of around 300 ka is indicated if, as is apparent, radioactive decay is the only significant cause of 36Cl/Cl variation within the aquifer. A review of previous, often controversial, 36Cl decay studies shows results are usually ambiguous due to lack of certainty when factoring subsurface Cl- addition into decay calculations. Apparently, due to the thickness of the Hermannsburg Sandstone, no subsurface sources of Cl- such as aquitards or halites, are encountered along groundwater flow paths, hence the clear 36Cl decay trend seen. The classic homogenous aquifer with varying surface topography, the "Toth" flow model, is the simplest conceptual model that need be invoked to explain these isotope data. Complexities, associated with local topography flow cells superimposed on the regional gradient, signify groundwater with markedly different flow path lengths has been sampled. The long travel times (> 100 ka) indicate groundwater discharge would endure through arid phases associated with Quaternary climate oscillations. Such a flow system can explain the persistence of this arid zone groundwater-dependent ecosystem and highlight the possibility that Palm Valley has acted as a flora refuge since at least the mid- Pleistocene.

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2

Eberhard, Stefan M. "Ecology and hydrology of a threatened groundwater-dependent ecosystem: the Jewel Cave karst system in Western Australia." Thesis, Eberhard, Stefan M. (2004) Ecology and hydrology of a threatened groundwater-dependent ecosystem: the Jewel Cave karst system in Western Australia. PhD thesis, Murdoch University, 2004. https://researchrepository.murdoch.edu.au/id/eprint/61/.

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Groundwater is a significant component of the world's water balance and accounts for >90 % of usable freshwater. Around the world groundwater is an important source of water for major cities, towns, industries, agriculture and forestry. Groundwater plays a role in the ecological processes and 'health' of many surface ecosystems, and is the critical habitat for subterranean aquatic animals (stygofauna). Over-abstraction or contamination of groundwater resources may imperil the survival of stygofauna and other groundwater-dependent ecosystems (GDEs). In two karst areas in Western Australia (Yanchep and Leeuwin-Naturaliste Ridge), rich stygofauna communities occur in cave waters containing submerged tree roots. These aquatic root mat communities were listed as critically endangered because of declining groundwater levels, presumably caused by lower rainfall, groundwater abstraction, and/or forest plantations. Investigation of the hydrology and ecology of the cave systems was considered essential for the conservation and recovery of these threatened ecological communities (TECs). This thesis investigated the hydrology and ecology of one of the TECs, located in the Jewel Cave karst system in the Leeuwin-Naturaliste Ridge. A multi-disciplinary approach was used to explore aspects pertinent to the hydrology and ecology of the groundwater system. Thermoluminescence dating of the limestone suggested that development of the karst system dates from the Early Pleistocene and that caves have been available for colonisation by groundwater fauna since that time. Speleogenesis of the watertable maze caves occurred in a flank margin setting during earlier periods of wetter climate and/or elevated base levels. Field mapping and leveling were used to determine hydrologic relationships between caves and the boundaries of the karst aquifer. Monitoring of groundwater levels was undertaken to characterise the conditions of recharge, storage, flow and discharge. A hydrogeologic model of the karst system was developed. The groundwater hydrograph for the last 50 years was reconstructed from old photographs and records whilst radiometric dating and leveling of stratigraphic horizons enabled reconstruction of a history of watertable fluctuations spanning the Holocene to Late Pleistocene. The watertable fluctuations over the previous 50 years did not exceed the range of fluctuations experienced in the Quaternary history, including a period 11,000 to 13,000 years ago when the watertable was lower than the present level. The recent groundwater decline in Jewel Cave was not reflected in the annual rainfall trend, which was above average during the period (1976 to 1988) when the major drop in water levels occurred. Groundwater abstraction and tree plantations in nearby catchments have not contributed to the groundwater decline as previously suggested. The period of major watertable decline coincided with a substantial reduction in fire frequency within the karst catchment. The resultant increase in understorey vegetation and ground litter may have contributed to a reduction in groundwater recharge, through increased evapotranspiration and interception of rainfall. To better understand the relationships between rainfall, vegetation and fire and their effects on groundwater recharge, an experiment is proposed that involves a prescribed burn of the cave catchment with before-after monitoring of rainfall, leaf-area, ground litter, soil moisture, vadose infiltration and groundwater levels. Molecular genetic techniques (allozyrne electrophoresis and mitochondria1 DNA) were used to assess the species and population boundaries of two genera and species of cave dwelling Amphipoda. Populations of both species were largely panrnictic which was consistent with the hydrogeologic model. The molecular data supported the conclusion that both species of amphipod have survived lower watertable levels experienced in the caves during the Late Pleistocene. A mechanism for the colonization and isolation of populations in caves is proposed. Multi Dimensional Scaling was used to investigate patterns in groundwater biodiversity including species diversity, species assemblages, habitat associations and biogeography. Faunal patterns were related to abiotic environmental parameters. Investigation of hydrochemistry and water quality characterized the ecological water requirements (EWR) of the TEC and established a baseline against which to evaluate potential impacts such as groundwater pollution. The conservation status of the listed TEC was significantly improved by increasing the number of known occurrences and distribution range of the community (from 10 m2 to > 2 x lo6 m2), and by showing that earlier perceived threatening processes (rainfall decline, groundwater pumping, tree plantations) were either ameliorated or inoperative within this catchment. The GDE in the Jewel Cave karst system may not have been endangered by the major phase of watertable decline experienced 1975-1987, or by the relatively stable level experienced up until 2000. However, if the present trend of declining rainfall in southwest Wester,,Australia continues, and the cave watertable declines > 0.5 m below the present level, then the GDE may become more vulnerable to extinction. The occurrence and distribution of aquatic root mat communities and related groundwater fauna in other karst catchments in the Leeuwin-Naturaliste Ridge is substantially greater than previously thought, however some of these are predicted to be threatened by groundwater pumping and pollution associated with increasing urban and rural developments. The taxonomy of most stygofauna taxa and the distribution of root mat communities is too poorly known to enable proper assessment of their conservation requirements. A regional-scale survey of stygofauna in southwest Western Australia is required to address this problem. In the interim, conservation actions for the listed TECs need to be focused at the most appropriate spatial scale, which is the karst drainage system and catchment area. Conservation of GDEs in Western Australia will benefit fi-om understanding and integration with abiotic groundwater system processes, especially hydrogeologic and geomorphic processes.

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3

Eberhard, Stefan M. "Ecology and hydrology of a threatened groundwater-dependent ecosystem : the Jewel Cave karst system in Western Australia /." Access via Murdoch University Digital Theses Project, 2004. http://wwwlib.murdoch.edu.au/adt/browse/view/adt-MU20051010.141551.

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4

au, Stefan@calm wa gov, and Stefan Eberhard. "Ecology and Hydrology of a Threatened Groundwater-Dependent Ecosystem:The Jewel Cave Karst System in Western Australia." Murdoch University, 2004. http://wwwlib.murdoch.edu.au/adt/browse/view/adt-MU20051010.141551.

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Abstract:

Groundwater is a significant component of the world's water balance and accounts for >90 % of usable freshwater. Around the world groundwater is an important source of water for major cities, towns, industries, agriculture and forestry. Groundwater plays a role in the ecological processes and 'health' of many surface ecosystems, and is the critical habitat for subterranean aquatic animals (stygofauna). Over-abstraction or contamination of groundwater resources may imperil the survival of stygofauna and other groundwater-dependent ecosystems (GDEs). In two karst areas in Western Australia (Yanchep and Leeuwin-Naturaliste Ridge), rich stygofauna communities occur in cave waters containing submerged tree roots. These aquatic root mat communities were listed as critically endangered because of declining groundwater levels, presumably caused by lower rainfall, groundwater abstraction, and/or forest plantations. Investigation of the hydrology and ecology of the cave systems was considered essential for the conservation and recovery of these threatened ecological communities (TECs). This thesis investigated the hydrology and ecology of one of the TECs, located in the Jewel Cave karst system in the Leeuwin-Naturaliste Ridge. A multi-disciplinary approach was used to explore aspects pertinent to the hydrology and ecology of the groundwater system. Thermoluminescence dating of the limestone suggested that development of the karst system dates from the Early Pleistocene and that caves have been available for colonisation by groundwater fauna since that time. Speleogenesis of the watertable maze caves occurred in a flank margin setting during earlier periods of wetter climate and/or elevated base levels. Field mapping and leveling were used to determine hydrologic relationships between caves and the boundaries of the karst aquifer. Monitoring of groundwater levels was undertaken to characterise the conditions of recharge, storage, flow and discharge. A hydrogeologic model of the karst system was developed. The groundwater hydrograph for the last 50 years was reconstructed from old photographs and records whilst radiometric dating and leveling of stratigraphic horizons enabled reconstruction of a history of watertable fluctuations spanning the Holocene to Late Pleistocene. The watertable fluctuations over the previous 50 years did not exceed the range of fluctuations experienced in the Quaternary history, including a period 11,000 to 13,000 years ago when the watertable was lower than the present level. The recent groundwater decline in Jewel Cave was not reflected in the annual rainfall trend, which was above average during the period (1 976 to 1988) when the major drop in water levels occurred. Groundwater abstraction and tree plantations in nearby catchments have not contributed to the groundwater decline as previously suggested. The period of major watertable decline coincided with a substantial reduction in fire frequency within the karst catchment. The resultant increase in understorey vegetation and ground litter may have contributed to a reduction in groundwater recharge, through increased evapotranspiration and interception of rainfall. To better understand the relationships between rainfall, vegetation and fire and their effects on groundwater recharge, an experiment is proposed that involves a prescribed burn of the cave catchment with before-after monitoring of rainfall, leaf-area, ground litter, soil moisture, vadose infiltration and groundwater levels. Molecular genetic techniques (allozyrne electrophoresis and mitochondria1 DNA) were used to assess the species and population boundaries of two genera and species of cave dwelling Amphipoda. Populations of both species were largely panrnictic which was consistent with the hydrogeologic model. The molecular data supported the conclusion that both species of amphipod have survived lower watertable levels experienced in the caves during the Late Pleistocene. A mechanism for the colonization and isolation of populations in caves is proposed. Multi Dimensional Scaling was used to investigate patterns in groundwater biodiversity including species diversity, species assemblages, habitat associations and biogeography. Faunal patterns were related to abiotic environmental parameters. Investigation of hydrochemistry and water quality characterized the ecological water requirements (EWR) of the TEC and established a baseline against which to evaluate potential impacts such as groundwater pollution. The conservation status of the listed TEC was significantly improved by increasing the number of known occurrences and distribution range of the community (from 10 m2 to > 2 x lo6 m2), and by showing that earlier perceived threatening processes (rainfall decline, groundwater pumping, tree plantations) were either ameliorated or inoperative within this catchment. The GDE in the Jewel Cave karst system may not have been endangered by the major phase of watertable decline experienced 1975-1987, or by the relatively stable level experienced up until 2000. However, if the present trend of declining rainfall in southwest Wester,,Australia continues, and the cave watertable declines > 0.5 m below the present level, then the GDE may become more vulnerable to extinction. The occurrence and distribution of aquatic root mat communities and related groundwater fauna in other karst catchments in the Leeuwin-Naturaliste Ridge is substantially greater than previously thought, however some of these are predicted to be threatened by groundwater pumping and pollution associated with increasing urban and rural developments. The taxonomy of most stygofauna taxa and the distribution of root mat communities is too poorly known to enable proper assessment of their conservation requirements. A regional-scale survey of stygofauna in southwest Western Australia is required to address this problem. In the interim, conservation actions for the listed TECs need to be focused at the most appropriate spatial scale, which is the karst drainage system and catchment area. Conservation of GDEs in Western Australia will benefit fi-om understanding and integration with abiotic groundwater system processes, especially hydrogeologic and geomorphic processes.

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5

Eberhard, Stefan. "Ecology and hydrology of a threatened groundwater-dependent ecosystem: the Jewel Cave karst system in Western Australia." Eberhard, Stefan (2004) Ecology and hydrology of a threatened groundwater-dependent ecosystem: the Jewel Cave karst system in Western Australia. PhD thesis, Murdoch University, 2004. http://researchrepository.murdoch.edu.au/61/.

Full text

Abstract:

Groundwater is a significant component of the world's water balance and accounts for >90 % of usable freshwater. Around the world groundwater is an important source of water for major cities, towns, industries, agriculture and forestry. Groundwater plays a role in the ecological processes and 'health' of many surface ecosystems, and is the critical habitat for subterranean aquatic animals (stygofauna). Over-abstraction or contamination of groundwater resources may imperil the survival of stygofauna and other groundwater-dependent ecosystems (GDEs). In two karst areas in Western Australia (Yanchep and Leeuwin-Naturaliste Ridge), rich stygofauna communities occur in cave waters containing submerged tree roots. These aquatic root mat communities were listed as critically endangered because of declining groundwater levels, presumably caused by lower rainfall, groundwater abstraction, and/or forest plantations. Investigation of the hydrology and ecology of the cave systems was considered essential for the conservation and recovery of these threatened ecological communities (TECs). This thesis investigated the hydrology and ecology of one of the TECs, located in the Jewel Cave karst system in the Leeuwin-Naturaliste Ridge. A multi-disciplinary approach was used to explore aspects pertinent to the hydrology and ecology of the groundwater system. Thermoluminescence dating of the limestone suggested that development of the karst system dates from the Early Pleistocene and that caves have been available for colonisation by groundwater fauna since that time. Speleogenesis of the watertable maze caves occurred in a flank margin setting during earlier periods of wetter climate and/or elevated base levels. Field mapping and leveling were used to determine hydrologic relationships between caves and the boundaries of the karst aquifer. Monitoring of groundwater levels was undertaken to characterise the conditions of recharge, storage, flow and discharge. A hydrogeologic model of the karst system was developed. The groundwater hydrograph for the last 50 years was reconstructed from old photographs and records whilst radiometric dating and leveling of stratigraphic horizons enabled reconstruction of a history of watertable fluctuations spanning the Holocene to Late Pleistocene. The watertable fluctuations over the previous 50 years did not exceed the range of fluctuations experienced in the Quaternary history, including a period 11,000 to 13,000 years ago when the watertable was lower than the present level. The recent groundwater decline in Jewel Cave was not reflected in the annual rainfall trend, which was above average during the period (1976 to 1988) when the major drop in water levels occurred. Groundwater abstraction and tree plantations in nearby catchments have not contributed to the groundwater decline as previously suggested. The period of major watertable decline coincided with a substantial reduction in fire frequency within the karst catchment. The resultant increase in understorey vegetation and ground litter may have contributed to a reduction in groundwater recharge, through increased evapotranspiration and interception of rainfall. To better understand the relationships between rainfall, vegetation and fire and their effects on groundwater recharge, an experiment is proposed that involves a prescribed burn of the cave catchment with before-after monitoring of rainfall, leaf-area, ground litter, soil moisture, vadose infiltration and groundwater levels. Molecular genetic techniques (allozyrne electrophoresis and mitochondria1 DNA) were used to assess the species and population boundaries of two genera and species of cave dwelling Amphipoda. Populations of both species were largely panrnictic which was consistent with the hydrogeologic model. The molecular data supported the conclusion that both species of amphipod have survived lower watertable levels experienced in the caves during the Late Pleistocene. A mechanism for the colonization and isolation of populations in caves is proposed. Multi Dimensional Scaling was used to investigate patterns in groundwater biodiversity including species diversity, species assemblages, habitat associations and biogeography. Faunal patterns were related to abiotic environmental parameters. Investigation of hydrochemistry and water quality characterized the ecological water requirements (EWR) of the TEC and established a baseline against which to evaluate potential impacts such as groundwater pollution. The conservation status of the listed TEC was significantly improved by increasing the number of known occurrences and distribution range of the community (from 10 m2 to > 2 x lo6 m2), and by showing that earlier perceived threatening processes (rainfall decline, groundwater pumping, tree plantations) were either ameliorated or inoperative within this catchment. The GDE in the Jewel Cave karst system may not have been endangered by the major phase of watertable decline experienced 1975-1987, or by the relatively stable level experienced up until 2000. However, if the present trend of declining rainfall in southwest Wester,,Australia continues, and the cave watertable declines > 0.5 m below the present level, then the GDE may become more vulnerable to extinction. The occurrence and distribution of aquatic root mat communities and related groundwater fauna in other karst catchments in the Leeuwin-Naturaliste Ridge is substantially greater than previously thought, however some of these are predicted to be threatened by groundwater pumping and pollution associated with increasing urban and rural developments. The taxonomy of most stygofauna taxa and the distribution of root mat communities is too poorly known to enable proper assessment of their conservation requirements. A regional-scale survey of stygofauna in southwest Western Australia is required to address this problem. In the interim, conservation actions for the listed TECs need to be focused at the most appropriate spatial scale, which is the karst drainage system and catchment area. Conservation of GDEs in Western Australia will benefit fi-om understanding and integration with abiotic groundwater system processes, especially hydrogeologic and geomorphic processes.

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6

Puckridge, James Terence. "The role of hydrology in the ecology of Cooper Creek, Central Australia : implications for the flood pulse concept /." Title page, abstract and contents only, 1999. http://web4.library.adelaide.edu.au/theses/09PH/09php9774.pdf.

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7

Bari, Mohammed A. "A distributed conceptual model for stream salinity generation processes : a systematic data-based approach." University of Western Australia. School of Earth and Geographical Sciences, 2006. http://theses.library.uwa.edu.au/adt-WU2006.0058.

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[Truncated abstract] During the last fifty years mathematical models of catchment hydrology have been widely developed and used for hydrologic forecasting, design and water resources management. Most of these models need large numbers of parameters to represent the flow generation process. The model parameters are estimated through calibration techniques and often lead to ‘unrealistic’ values due to structural error in the model formulations. This thesis presents a new strategy for developing catchment hydrology models for representing streamflow and salinity generation processes. The strategy seeks to ‘learn from data’ in order to specify a conceptual framework that is appropriate for the particular space and time scale under consideration. Initially, the conceptual framework is developed by considering large space and time scales. The space and time scales are then progressively reduced and conceptual model complexity systematically increased until ultimately, an adequate simulation of daily streamflow and salinity is achieved. This strategy leads to identification of a few key physically meaningful parameters, most of which can be estimated a priori and with minimal or no calibration. Initially, the annual streamflow data from ten experimental catchments (control and cleared for agriculture) were analysed. The streamflow increased in two phases: (i) immediately after clearing due to reduced evapotranspiration, and (ii) through an increase in stream zone saturated area. The annual evapotranspiration losses from native vegetation and pasture, the ‘excess’ water (resulting from reduced transpiration after land use change), runoff and deep storage were estimated by a simple water balance model. The model parameters are obtained a priori without calibration. The annual model was then elaborated by analysing the monthly rainfall-runoff, groundwater and soil moisture data from four experimental catchments. Ernies (control, fully forested) and Lemon (53% cleared) catchments are located in zone with a mean annual rainfall of 725 mm. Salmon (control, fully forested) and Wights (100% cleared) are located in zone with mean annual rainfall of 1125 mm. Groundwater levels rose and the stream zone saturated area increased significantly after clearing. From analysis of this data it was evident that at a monthly time step the conceptual model framework needed to include a systematic gain/loss to storage component in order to adequately describe the observed lags between peak monthly rainfall and runoff.

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Graham, Tennille. "Economics of protecting road infrastructure from dryland salinity in Western Australia." University of Western Australia. School of Agricultural and Resource Economics, 2009. http://theses.library.uwa.edu.au/adt-WU2009.0207.

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[Truncated abstract] The salinisation of agricultural land, urban infrastructure and natural habitat is a serious and increasing problem in southern Australia. Government funding has been allocated to the problem to attempt to reduce substantial costs associated with degradation of agricultural and non-agricultural assets. Nevertheless, Government funding has been small relative to the size of the problem and therefore expenditure needs to be carefully targeted to interventions that will achieve the greatest net benefits. For intervention to be justified, the level of salinity resulting from private landholder decisions must exceed the level that is optimal from the point of view of society as a whole, and the costs of government intervention must be less than the benefits gained by society. This study aims to identify situations when government intervention is justified to manage dryland salinity that threatens to affect road infrastructure (a public asset). A key gap in the environmental economics literature is research that considers dryland salinity as a pollution that has off-site impacts on public assets. This research developed two hydrological/economic models to achieve this objective. The first was a simple economic model representing external costs from dryland salinity. This model was used to identify those variables that have the biggest impact on the net-benefits possible from government intervention. The second model was a combined hydro/economic model that represents the external costs from dryland salinity on road infrastructure. The hydrological component of the model applied the method of metamodelling to simplify a complex, simulation model to equations that could be easily included in the economic model. The key variables that have the biggest impact on net-benefits of dryland salinity mitigation were the value of the off-site asset and the time lag before the onset of dryland salinity in the absence of intervention. ... In the case study of dryland salinity management in the Date Creek subcatchment of Western Australia, the economics of vegetation-based and engineering strategies were investigated for road infrastructure. In general, the engineering strategies were more economically beneficial than vegetation-based strategies. In the case-study catchment, the cost of dryland salinity affecting roads was low relative to the cost to agricultural land. Nevertheless, some additional change in land management to reduce impacts on roads (beyond the changes justified by agricultural land alone) was found to be optimal in some cases. Reinforcing the results from the simple model, a key factor influencing the economics of dryland salinity management was the urgency of the problem. If costs from dryland salinity were not expected to occur until 30 years or more, the optimal response in the short-term was to do nothing. Overall, the study highlights the need for governments to undertake comprehensive and case-specific analysis before committing resources to the management of dryland salinity affecting roads. There were many scenarios in the modelling analysis where the benefits of interventions would not be sufficient to justify action.

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Smith, Margaret G. "Hydrogeology of the Lake Muir–Unicup Catchment, Western Australia: an ecologically important area experiencing hydrologic change." Thesis, Curtin University, 2010. http://hdl.handle.net/20.500.11937/1580.

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Identified in the Western Australian Government’s 1996 Salinity Action Plan as an important natural diversity area at risk from changing hydrology, the Lake Muir– Unicup Natural Diversity Catchment is in need of urgent management to minimise impacts to lake hydrology and vegetation health. Many of the wetlands in the south of the catchment have been designated under the Ramsar Convention as Wetlands of International Importance. Other wetlands elsewhere in the catchment have been prioritised according to the Convention guidelines and are awaiting to be officially listed.In the 1980 to 1990s changing hydrology related to land clearing was considered to result in dry-land salinisation. Although low pH groundwater was noted during the groundwater monitoring between 1997 and 2001, the implications of groundwater acidification were not realised. Groundwater acidification cannot be taken in isolation, and it quickly became apparent that a viable management plan could not be formulated until the hydrogeology and geochemistry were better understood.The aquifers present today are the result of a landscape that evolved during and since Australia and Antarctica rifted apart. The separation of these two land masses has resulted in the formation and preservation of five regolith units that make up the three aquifers: the surficial; the sedimentary; and the fractured and/or weathered basement rock aquifers. The late Eocene topography was modelled using known depth to basement rock and reprocessed airborne magnetic data, enabling the lateral and verticals extent of the aquifers to be determined.The hydraulic head data within the mapped aquifers led to the identification of a closed groundwater basin in the south of the study area with groundwater TDS values up to three times seawater.Three distinct hydrochemical facies have been recognised and in keeping with the marine aerosol signature the majority of the groundwater is a Na–Cl type water. The fractured and/or weathered basement rock aquifer in the south of the study area contains a water where the major cations are Ca and Na and is referred to as a Ca– Na–Cl type water. Anthropogenic process have resulted in the a Na–Mg–SO[subscript]4 type water associated with draining a peat swamp with the aim of mining the peat.All three aquifers contain iron rich water, and pyrite has been identified in the sedimentary aquifer and fractured and/or weathered basement rock aquifer. Of the three aquifers the sedimentary aquifer is the most likely to contain groundwaters with pH up to 6.3 that have minimal buffering capacity.

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Boggs, Dimity. "Playas of the Yarra Yarra drainage system, Western Australia." University of Western Australia. School of Earth and Geographical Sciences, 2009. http://theses.library.uwa.edu.au/adt-WU2009.0074.

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This thesis examines playas as integrated ecosystems, through investigation of long- and short-term processes associated with playa geomorphology, hydrology and diatom ecology, in playas of the Yarra Yarra drainage system of Western Australia. This landscape approach was conducted at a range of scales and consequently revealed a level of heterogeneity not previously described in Australian playas. The key result and common thread linking the three facets of the playas investigated is the importance of hydroperiod in defining the playa environment. The morphology and distribution of playas are described and the results presented of an examination of potential mechanisms determining intra-system variability. Measurements of the physical attributes of the playas, including length, area, shape, density and orientation, were made through Geographic Information System analysis and detailed interpretation of aerial photography. Two main morphological groups are distinguished: small (<10 ha), elliptical to circular playas with a NNW-SSE orientation; and large (>30 ha), elongated playas. Regional patterns in geomorphic attributes are markedly different between the west and east sides of the system. The boundary between the two regions coincides approximately with rainfall distribution. In this respect, climate is an overarching driver of geomorphological variation but sub-catchment characteristics are also critical determinants. Littoral drift and segmentation processes that are common to coastal lagoons but not commonly described in playas were identified from visual interpretation of aerial photographs of spits, bars and cuspate shorelines. Six small playas, representing an hydrological continuum from mostly wet to mostly dry, were selected for investigation of their hydrology and diatom ecology, enabling assessment ii of the variability of hydrology, hydrochemistry and of the effects of different hydrological environments on the distribution of taxa. Hydroperiod was highly variable and central to determining playa geomorphology and biology. In the six playas it ranged from 19 to over 211 days, and filling frequency from 1 to 3 cycles between 2002 and 2004, reflecting rainfall and sub-catchment variability. Monitoring a series of nested piezometers revealed that the playas were net discharge points for ground water over the period of survey. However, small local vertical head variations indicate ground water does not discharge at the same rate across the playa surfaces and that playas may have short-lived phases of ground water recharge. Hydrochemically, the playas are typical of salt lakes in Australia. They displayed a wide range of salinity values, neutral to alkaline pH and ionic composition similar to sea water. It is postulated that the geochemical evolution of waters in the playas follows a pathway where low salinity recharge waters with dilute sea water salts progress to Na-Cl dominated brines through evaporative concentration. Surface waters showed an ionic dominance consistent with sea water with minor variations attributed to transitional phases in the geochemical evolution of the waters. Shallow ground waters showed a common and consistent pattern of ionic dominance: Na+ >Mg2+ >K+ >Ca2+ : Cl- >SO4 2- >HCO3 ->CO3 2-.

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Wang, Qing. "Impacts of climate, topography, and weathering profile on vadose zone hydrology and coastal pine plantation management : a multi-scale investigation, Southeast Queensland, Australia." Thesis, Queensland University of Technology, 2008. https://eprints.qut.edu.au/20657/1/Wang_Qing_Thesis.pdf.

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Exotic pine plantations are a major landuse within the coastal lowlands of southeast Queensland, extending from close to the shoreline to the hinterland ranges. These plantations are within a sub-tropical climatic zone, and in most years, the summers are appreciably wetter than the winters. This terrain, in general, has been highly weathered and the soils are poor in nutrients. Environmental factors such as the climate, topography and weathering profile (including soil) are found to be important controls on vadose zone hydrology, which, in turn, has a great impact on tree growth and consequently on the design of management practices. This research project takes a holistic approach to investigate the influence of these environmental factors at different scales, and is designed to fulfil the following objectives: (1) To build a spatial model of forest productivity for the entire Tuan Toolara State Forest (TTSF), southeast Queensland, by analysing the spatial patterns of many environmental variables that may have controls on soil water distribution. (2) To determine how some of these environmental factors are responsible for the development of water-logging and soil salinisation by examining in detail an area of low site index that is severely affected by these two processes. (3) To develop a model to assess the risks of water-logging spatially and temporally. A multiple regression model was constructed to predict the forest productivity (measured by the value of site index, the average dominant tree height at 25 years of age). The independent variables were derived from a digital elevation model (elevation, slope, curvature, hillshade, flow accumulation and distance to streams), γ-ray spectrometry (potassium, thorium and uranium), and interpolated rainfall. The model explained up to 60% of the variance in the site indices and produced predictive maps of site index for two species: P. elliottii Engelm. and Queensland hybrid, a P. elliottii × P. caribaea Morelet hybrid. The model also identified the lowest site index area at the northern Tuan State Forest (NTSF), likely due to a greater risk of water-logging and salinisation. The NTSF area is of low relief and, therefore, the focus has been on the vertical controls of deep weathering profile. The methodology included setting up a network of groundwater bores screened at different depths within the weathering profile, characterising the profile (mineralogy, EC, and pH) and the groundwaters within it (water levels, physico-chemical parameters, major and minor ions). It is found that water-logging is caused by perched groundwater formed on top of the ferricrete or mottled saprolite after prolonged rainfall. Localised salinisation is related to the discharge of brackish groundwater occurring within the mottled saprolite. The deep aquifer within the coarse saprolite is fresh and not responsible for salinisation, a situation that differs from many other settings in Australia. The ability of using the Soil and Water Assessment Tool (SWAT) computer model to simulate soil water balance and to assess the risks of water-logging was tested in a selected catchment in the TTSF. The model successfully simulated stream flow at 2 weirs for a period of 6 years; the achieved R2 were 0.752 and 0.858, respectively. Long-term simulation for a 30-year period showed that there are pronounced seasonal patterns in rainfall and evapotranspiration as well as in soil water. For mature plantation with slopes of 3-15%, the mean annual duration of water-logging ranged from 161 days in the humus podzols, to 110 days in the gleyed podzolic, and to 90 days in the yellow podzolics. The outcomes of this research suggest that forest management can be strongly supported by understanding the impacts of these environmental factors (e.g. climate, topography and weathering profile) on vadose zone hydrological processes; the selection of optimum approach will depend on the research objective or purpose. The models and analytical tools that were developed or tested here have the potential to be successfully applied elsewhere if the input data are available.

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Wang, Qing. "Impacts of climate, topography, and weathering profile on vadose zone hydrology and coastal pine plantation management : a multi-scale investigation, Southeast Queensland, Australia." Queensland University of Technology, 2008. http://eprints.qut.edu.au/20657/.

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Exotic pine plantations are a major landuse within the coastal lowlands of southeast Queensland, extending from close to the shoreline to the hinterland ranges. These plantations are within a sub-tropical climatic zone, and in most years, the summers are appreciably wetter than the winters. This terrain, in general, has been highly weathered and the soils are poor in nutrients. Environmental factors such as the climate, topography and weathering profile (including soil) are found to be important controls on vadose zone hydrology, which, in turn, has a great impact on tree growth and consequently on the design of management practices. This research project takes a holistic approach to investigate the influence of these environmental factors at different scales, and is designed to fulfil the following objectives: (1) To build a spatial model of forest productivity for the entire Tuan Toolara State Forest (TTSF), southeast Queensland, by analysing the spatial patterns of many environmental variables that may have controls on soil water distribution. (2) To determine how some of these environmental factors are responsible for the development of water-logging and soil salinisation by examining in detail an area of low site index that is severely affected by these two processes. (3) To develop a model to assess the risks of water-logging spatially and temporally. A multiple regression model was constructed to predict the forest productivity (measured by the value of site index, the average dominant tree height at 25 years of age). The independent variables were derived from a digital elevation model (elevation, slope, curvature, hillshade, flow accumulation and distance to streams), γ-ray spectrometry (potassium, thorium and uranium), and interpolated rainfall. The model explained up to 60% of the variance in the site indices and produced predictive maps of site index for two species: P. elliottii Engelm. and Queensland hybrid, a P. elliottii × P. caribaea Morelet hybrid. The model also identified the lowest site index area at the northern Tuan State Forest (NTSF), likely due to a greater risk of water-logging and salinisation. The NTSF area is of low relief and, therefore, the focus has been on the vertical controls of deep weathering profile. The methodology included setting up a network of groundwater bores screened at different depths within the weathering profile, characterising the profile (mineralogy, EC, and pH) and the groundwaters within it (water levels, physico-chemical parameters, major and minor ions). It is found that water-logging is caused by perched groundwater formed on top of the ferricrete or mottled saprolite after prolonged rainfall. Localised salinisation is related to the discharge of brackish groundwater occurring within the mottled saprolite. The deep aquifer within the coarse saprolite is fresh and not responsible for salinisation, a situation that differs from many other settings in Australia. The ability of using the Soil and Water Assessment Tool (SWAT) computer model to simulate soil water balance and to assess the risks of water-logging was tested in a selected catchment in the TTSF. The model successfully simulated stream flow at 2 weirs for a period of 6 years; the achieved R2 were 0.752 and 0.858, respectively. Long-term simulation for a 30-year period showed that there are pronounced seasonal patterns in rainfall and evapotranspiration as well as in soil water. For mature plantation with slopes of 3-15%, the mean annual duration of water-logging ranged from 161 days in the humus podzols, to 110 days in the gleyed podzolic, and to 90 days in the yellow podzolics. The outcomes of this research suggest that forest management can be strongly supported by understanding the impacts of these environmental factors (e.g. climate, topography and weathering profile) on vadose zone hydrological processes; the selection of optimum approach will depend on the research objective or purpose. The models and analytical tools that were developed or tested here have the potential to be successfully applied elsewhere if the input data are available.

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Taffs, Kathryn Helen. "Surface water hydrological change in the upper South East of South Australia /." Title page, contents and abstract only, 1997. http://web4.library.adelaide.edu.au/theses/09PH/09pht124.pdf.

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Thesis (Ph. D.)--University of Adelaide, Dept. of Geography, 1997.
"Conducted as a cross-institutional student between the University of Adelaide and the Australian National Universiity." Includes bibliographical references.

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14

Napier, Malcolm B. "An integrated hydrological and hydrochemical study of surface and groundwaters in the Bungawalbin Creek catchment, northeast NSW, Australia." Thesis, Queensland University of Technology, 2017. https://eprints.qut.edu.au/103979/1/Malcolm_Napier_Thesis.pdf.

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This catchment-wide study examines the connections between surface waters and groundwaters in the Bungawalbin Creek drainage system, northern NSW, by integration of a variety of geoscientific techniques. A 3D geological model of the catchment was developed based on mapping and geophysical surveys, and geochemical, isotopic and hydrological data were used to established dynamic processes within this. The central role of the shallow, alluvial aquifer and its hydrological connections to surface waters was highlighted. Research outcomes have application in the future management of water resources, land management and climate variability in the area.

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Barr, Cameron. "The effects of European landuse practices on the hydrology of a wetland in the upper south east of South Australia and its implications for wetland management /." Title page, contents and abstract only, 2001. http://web4.library.adelaide.edu.au/theses/09AEVH/09aevhb268.pdf.

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Cordell, Dana. "Urine Diversion & Reuse in Australia : A homeless paradigm or sustainable solution for the future?" Thesis, Linköping University, Department of Water and Environmental Studies, 2006. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-8310.

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Diverting urine from faeces or mixed wastewater and reusing it to fertilize crops, is a traditional method used in Asia. It is also a contemporary approach to sustainable nutrient and water management in Scandinavia and other parts of Europe. Urine diversion and reuse is a proven socio-technical system that has significant potential benefits on both a local and global scale, such as recirculating scarce plant nutrients like phosphorus back to agriculture, reducing eutrophication of waterways and improving water and sanitation systems. This thesis explores the nature of these benefits in Australia and the global context and what barriers would need to be overcome if a urine diversion and reuse system were implemented in Australia to achieve significant environmental benefits. These questions are investigated through stakeholder interviews in Sweden, to identify the ‘lessons learnt’ from the Swedish experience with urine diversion and reuse, and, through interviews with relevant stakeholders in Australia to identify possible barriers and opportunities, costs and benefits, and roles and responsibilities in the Australian context. Findings from both the stakeholder interviews are triangulated with other sources of knowledge, such as the literature, personal communications and a qualitative assessment of costs and benefits.

This thesis found that while urine diversion is likely to benefit the Australia situation and warrants further research, these benefits are fragmented and spread across a range of discourses and separate institutions. Its acceptance and effective introduction into Australia might therefore be challenged by its lack of a single obvious organisational home. To overcome this and other identified challenges, several recommendations are made. For example, an Australian demonstration trial of urine diversion and reuse is recommended where clear drivers and opportunities exist, such as: in new developments adjacent to agricultural land; in regions where algal blooms are a critical problem and are predominantly caused by municipal sewage discharges; and where synergies with waterless urinals are being considered for water conservation value. This thesis does not promote urine diversion and reuse as the ‘silver bullet’ to Australia’s water and nutrient problems, however it does recommend that it be considered on an equal basis next to other possible options. For example, if reducing nutrient loads on receiving water bodies is a key objective, then a cost-effective analysis of urine diversion and reuse, compared to other options to reduce nutrient loads, could be undertaken, ensuring all relevant costs and benefits to the whole of society are included in the analysis.

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Colanzi, Piera. "Evoluzione del rischio idraulico nel bacino del Murray-Darling (Australia) dal 1975 ad oggi: applicazione combinata di modelli idraulici e dati satellitari." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2017.

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Da sempre gli insediamenti umani si sono stabiliti intorno ai corpi idrici, realizzando infrastrutture per il prelievo e l’immagazzinamento della risorsa idrica. Tale aspetto spesso oscura l’altro volto dell’acqua che da risorsa si trasforma in minaccia per la popolazione attraverso le inondazioni. Il Bacino del Murray – Darling (Australia) vive appieno la conflittualità derivante da questo bene. L’obiettivo del lavoro è analizzare per il periodo 1975 – 2014 le dinamiche di interazione uomo – allagamenti nel bacino. Ciò è consentito dalla disponibilità di dati a larga scala, quali modelli idraulici e immagini satellitari: le informazioni acquisibili da questi strumenti permettono la valutazione delle componenti concorrenti alla formazione del rischio idraulico, ovvero la pericolosità e l’esposizione. Queste ultime sono stimabili sulla base della localizzazione delle zone inondate, della frequenza di inondazione, della distribuzione delle aree edificate e della popolazione. Sebbene tali grandezze non rappresentano tutte quelle che contribuiscono alla determinazione del rischio, esse permettono di una valutazione delle dinamiche evolutive del rischio idraulico negli ultimi decenni. Le analisi condotte hanno evidenziato che le aree edificate e la popolazione hanno subito una crescita nel corso degli anni: tale comportamento sembra il sintomo di una scarsa consapevolezza del rischio alluvionale, oppure di una sua probabile accettazione a fronte dei vantaggi indotti dalla vicinanza alla fonte idrica.

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Ellaway, Edward Mark. "A study of the hydrochemistry of a limestone area : Buchan, East Gippsland /." Connect to thesis, 1991. http://repository.unimelb.edu.au/10187/1504.

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This thesis reports the results obtained, and conclusions made regarding research into the hydrochemistry of a small impounded karst area in southeastern Australia. Water samples were collected from a variety of sites over a period of approximately six years and include samples that are representative of baseflow (drought conditions) and flood (high flow conditions) the two extremes of the flow regime. Four distinct water types were found to be associated with the karst spring and cave water sites sampled. In terms of physical, chemical and computed parameter values these have been classed as TYPE 1 water (median parameter values similar to those noted for the surface stream sites sampled with catchments of non-carbonate material); TYPE 2 water (catchment predominantly of limestone); TYPE 3 water (catchment predominantly of dolomite); TYPE 4 water (high median chemical concentrations). Spatial variation within the study area is considerable and intrinsic factors such as catchment lithology, the residence time of recharge, aspect and vegetation cover are the major natural controls in determining physical and chemical characteristics.

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Wildy, Daniel Thomas. "Growing mallee eucalypts as short-rotation tree crops in the semi-arid wheatbelt of Western Australia." University of Western Australia. School of Plant Biology, 2004. http://theses.library.uwa.edu.au/adt-WU2004.0031.

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[Truncated abstract] Insufficient water use by annual crop and pasture species leading to costly rises in saline watertables has prompted research into potentially profitable deep-rooted perennial species in the Western Australian wheatbelt. Native mallee eucalypts are currently being developed as a short-rotation coppice crop for production of leaf oils, activated carbon and bio-electricity for low rainfall areas (300—450 mm) too dry for many of the traditional timber and forage species. The research in this study was aimed at developing a knowledge base necessary to grow and manage coppiced mallee eucalypts for both high productivity and salinity control. This firstly necessitated identification of suitable species, climatic and site requirements favourable to rapid growth, and understanding of factors likely to affect yield of the desirable leaf oil constituent, 1,8-cineole. This was undertaken using nine mallee taxa at twelve sites with two harvest regimes. E. kochii subsp. plenissima emerged as showing promise in the central and northern wheatbelt, particularly at a deep acid sand site (Gn 2.61; Northcote, 1979), so further studies focussed on physiology of its resprouting, water use and water-use efficiency at a similar site near Kalannie. Young E. kochii trees were well equipped with large numbers of meristematic foci and adequate root starch reserves to endure repeated shoot removal. The cutting season and interval between cuts were then demonstrated to have a strong influence on productivity, since first-year coppice growth was slow and root systems appeared to cease in secondary growth during the first 1.5—2.5 years after cutting. After decapitation, trees altered their physiology to promote rapid replacement of shoots. Compared to uncut trees, leaves of coppices were formed with a low carbon content per unit area, and showed high stomatal conductance accompanied by high leaf photosynthetic rates. Whole-plant water use efficiency of coppiced trees was unusually high due to their fast relative growth rates associated with preferential investments of photosynthates into regenerating canopies rather than roots. Despite relatively small leaf areas on coppice shoots over the two years following decapitation, high leaf transpiration rates resulted in coppices using water at rates far in excess of that falling as rain on the tree belt area. Water budgets showed that 20 % of the study paddock would have been needed as 0—2 year coppices in 5 m wide twin-row belts in order to maintain hydrological balance over the study period. Maximum water use occurred where uncut trees were accessing a fresh perched aquifer, but where this was not present water budgets still showed transpiration of uncut trees occurring at rates equivalent to 3—4 times rainfall incident on the tree belt canopy. In this scenario, only 10 % of the paddock surface would have been required under 5 m wide tree belts to restore hydrological balance, but competition losses in adjacent pasture would have been greater

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Schymanski, Stanislaus Josef. "Transpiration as the leak in the carbon factory : a model of self-optimising vegetation." University of Western Australia. School of Environmental Systems Engineering, 2007. http://theses.library.uwa.edu.au/adt-WU2007.0095.

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21

Samuel, Jos Martinus. "Effects of multi-scale rainfall variability on flood frequency : a comparative study of catchments in Perth, Newcastle and Darwin, Australia." University of Western Australia. School of Environmental Systems Engineering, 2008. http://theses.library.uwa.edu.au/adt-WU2009.0066.

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Issues arising from climate change and long-term natural climate variability have become the focus of much recent research. In this study, we specifically explore the impacts of long-term climate variability and climate changes upon flood frequencies. The analyses of the flood frequencies are carried out in a comparative manner in catchments located in semiarid-temperate and tropical landscapes in Australia, namely Perth, Newcastle and Darwin, using a process-based derived flood frequency approach. The derived flood frequency analyses are carried out using deterministic rainfall-runoff models that capture the intrinsic water balance variability in the study catchments, and driven by temporal rainfall event sequences that are generated by a stochastic rainfall model that incorporates temporal variabilities over a multiplicity of time scales, ranging from within-event, between-event to seasonal, multi-annual and multi-decadal time scales. Six climate scenarios are considered for Newcastle, that combine the ENSO (El Niño Southern Oscillation) and IPO (Inter-decadal Pacific Oscillation) modes of variability, and six different climate scenarios are considered for Perth and Darwin that combine these different ENSO modes and step changes in climate (upwards or downwards) that occurred in 1970 in both regions, which were identified through statistical analysis. The results of the analyses showed that La Niña years cause higher annual maximum floods compared to El Niño and Neutral years in all three catchments. The impact of ENSO on annual maximum floods in the Newcastle catchment is enhanced when the IPO is negative and for Perth, the impact of ENSO weakens in the post-1970 period, while it strengthens in Darwin in the same period. In addition, the results of sensitivity and scenario analyses with the derived flood frequency model explored the change of dominant runoff generation processes contributing to floods in each of the study catchments. These analyses highlighted a switch from subsurface stormflow to saturation excess runoff with a change of return period, which was much more pronounced in Perth and Darwin, and not so in Newcastle. In Perth and Darwin this switch was caused by the interactions between the out-of-phase seasonal variabilities of rainfall and potential evaporation, whereas the seasonality was much weaker in Newcastle. On the other hand, the combination of higher rainfall intensities and shallower soil depths led to saturation excess runoff being the dominant mechanism in Newcastle across the full range of return periods. Consequently, within-storm rainfall intensity patterns were important in Newcastle in all major flood producing events (all return periods), where they were only important in Perth and Darwin for floods of high return periods, which occur during wet months in wet years, when saturation excess runoff was the dominant mechanism. Additionally, due to the possibility of a change of process from subsurface stormflow to saturation excess when conditions suited this switch, the estimates of flood frequency are highly uncertain especially at high return periods (in Darwin and Perth) and much less in Newcastle (when no process change was involved).

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Poulter, Rachel. "Investigating the role of soil constraints on the water balance of some annual and perennial systems in a Mediterranean environment." University of Western Australia. Faculty of Agriculture, 2006. http://theses.library.uwa.edu.au/adt-WU2006.0018.

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This thesis compares the in situ water balance of common annual production systems (wheat, lupin, subclover and serradella) with a grazed perennial system (lucerne) at a site in the Avon Catchment, Western Australia. Using a physically-based water balance approach the value of a plant based solution in redressing the hydrological imbalance that has become a feature of much of the dryland agricultural region of Western Australia is investigated. The effectiveness of lucerne in providing greater available storage for buffering large rainfall events, as compared to the annual systems, is illustrated. Continued transpiration following out-of-season rainfall events maintains a larger available storage capacity. In contrast, the annual systems that are fallow over summer only withdrew a small fraction of water by soil evaporation between rainfall events. Under annual systems, the profile moisture store was sequentially increased to the extent that additional increments of rainfall could potentially contribute to deep drainage. A particular focus of this study has been to investigate the presence of soil constraints to root growth, and to assess how these constraints affect the water balance. A site survey indicated the soil penetration resistance was sufficient to impose a physical constraint to root growth. Published literature on the site shows soil acidity is also at a level imposing chemical constraints to root growth. A root growth model “Rootmodel”, for predicting root growth with and without soil constraints is examined in detail as a method for providing root growth parameters for inclusion into the numerical water balance model, SWIM based on Richard’s equation. Functions developed from “Rootmodel” adequately describe the effect of profile limitations to root growth, such as soil strength, moisture availability and temperature. Recommendations are made for inclusion of a growth suppressing function in “rootmodel” based on the chemical limitation of low pH. The effects of soil acidity on the root growth of several species is investigated experimentally and the resultant root data provided a reference point by which the simplified prediction of root growth built into SWIM could be adjusted using a linear reduction function. A similar linear reduction function is also employed to impose a physical constraint in the form of high penetration resistance.

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Hearman, Amy. "A modelling study into the effects of rainfall variability and vegetation patterns on surface runoff for semi-arid landscapes." University of Western Australia. School of Earth and Geographical Sciences, 2008. http://theses.library.uwa.edu.au/adt-WU2009.0047.

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[Truncated abstract] Generally hydrologic and ecologic models operate on arbitrary time and space scales, selected by the model developer or user based on the availability of field data. In reality rainfall is highly variable not only annually, seasonally and monthly but also the intensities within a rainfall event and infiltration properties on semi-arid hillslopes can also be highly variable as a result of discontinuous vegetation cover that form mosaics of areas with vegetation and areas of bare soil. This thesis is directed at improving our understanding of the impacts of the temporal representation of rainfall and spatial heterogeneity on model predictions of hydrologic thresholds and surface runoff coefficients on semi-arid landscapes at the point and hillslope scales. We firstly quantified within storm rainfall variability across a climate gradient in Western Australia by parameterizing the bounded random cascade rainfall model with one minute rainfall from 15 locations across Western Australia. This study revealed that rainfall activity generated in the tropics had more within storm variability and a larger proportion of the storm events received the majority of rain in the first half of the event. Rainfall generated from fontal activity in the south was less variable and more evenly distributed throughout the event. Parameters from the rainfall analysis were then used as inputs into a conceptual point scale surface runoff model to investigate the sensitivity of point scale surface runoff thresholds to the resolution of rainfall inputs. This study related maximum infiltration capacities to average storm intensities (k*) and showed where model predictions of infiltration excess were most sensitive to rainfall resolution (ln k* = 0.4) and where using time averaged rainfall data can lead to an under prediction of infiltration excess and an over prediction of the amount of water entering the soil (ln k* > 2). For soils susceptible to both infiltration excess and saturation excess, total runoff sensitivity was scaled by relating drainage coefficients to average storm intensities (g*) and parameter ranges where predicted runoff was dominated by infiltration excess or saturation excess depending on the resolution of rainfall data were determined (ln g* <2). The sensitivity of surface runoff predictions and the influence of specific within storm properties were then analysed on the hillslope scale. '...' It was found that using the flow model we still get threshold behaviour in surface runoff. Where conditions produce slow surface runoff velocities, spatial heterogeneity and temporal heterogeneity influences hillslope surface runoff amounts. Where conditions create higher surface runoff velocities, the temporal structure of within storm intensities has a larger influence on runoff amounts than spatial heterogeneity. Our results show that a general understanding of the prevailing rainfall conditions and the soil's infiltration capacity can help in deciding whether high rainfall resolutions (below 1 h) are required for accurate surface runoff predictions. The results of this study can be considered a contribution to understanding the way within storm properties effect the processes on the hillslope under a range of overall storm, slope and infiltration conditions as well as an improved understanding of how different vegetation patterns function to trap runoff at different total vegetation covers and rainfall intensities.

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Dao, Minh Truong, and n/a. "The use of remote sensing to monitor land use change and assess its effect on the hydrology of Tuggeranong Creek catchment." University of Canberra. Resource, Environmental & Heritage Sciences, 1993. http://erl.canberra.edu.au./public/adt-AUC20061109.154118.

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Since the launch of the first earth resources monitoring satellite, remote sensing imagery has been used to provide information on the progress of urbanization, and land cover and land use change. The launch of the first SPOT satellite marked a significant improvement in spatial and spectral resolution for discriminating individual targets and increased the potential to acquire more information regarding land cover and land use. This study aims to investigate the capability of using SPOT digital imagery for monitoring land use change in the urbanised catchment of Tuggeranong Creek in the Australia Capital Territory, and assess its effects on catchment hydrology. SPOT multispectral and panchromatic imagery was acquired over the study area for January 1987 and September 1990. This imagery was digitally processed and analysed using microBRIAN (MB) V3.01 software to derive information on land cover and land use within the catchment. Multi-temporal imagery was co-registered to a base map with sub-output pixel accuracy. In order to improve spatial resolution, the multispectral imagery was merged with panchromatic imagery acquired on the same day using HIS and HPF techniques. The HPF technique retained more integrity of the original multispectral data than did the HIS technique. Both HPF merged and unmerged (original) image sets were used to assess the possibility of using higher spatial resolution imagery in subsequent classification and change detection analysis. On the basis of statistical calculation, non-vegetation classification results were found to be consistent between merged and un-merged imagery, but not consistent for vegetation classes. The inconsistency was found to be the result of seasonal differences in phenology and sun angle. However more small sub-pixel sized features such as houses and lawns were identified using merged imagery. Regression differencing and post classification comparisons were performed on both merged and unmerged image sets to detect temporal changes which had occurred between both image dates. As expected, merged imagery led to more sub-pixel sized examples of change being highlighted using both the HPF and HIS techniques. However, errors associated with multi-temporal image registration, compounded by classification errors arising viI from seasonal differences, meant that the reliability of all identified incidences of change could not be validated. Nevertheless, post classification change detection was found to be the most useful approach for identifying the nature of change from one type of land use to another. The results of classification and change detection techniques were used to diagnose likely changes in catchment hydrology attributable to changes in land use. Preliminary hydrologic analyses found that catchment yield is more sensitive to changes in land use than runoff volume or peak flood discharge. This study confirms that SPOT imagery can be used for mapping and monitoring land use change in urban areas. SPOT imagery was found to be suitable for providing information on land use and land cover changes and assessing the likely hydrologic consequences of such change. The use of imagery from anniversary dates would further improve the reliability of hydrologic assessments based on remote sensing of land use change.

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Sun, Hua. "Digital terrain modelling of catchment erosion and sedimentation /." Title page, contents and abstract only, 1998. http://web4.library.adelaide.edu.au/theses/09PH/09phs9565.pdf.

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Powell, Paula Angele. "The effects of hydrology and nutrient inputs at South Milton Ley on the ecology of the common reed Phragmites australis (Cav. Trin. ex Steudal)." Thesis, University of Plymouth, 2000. http://hdl.handle.net/10026.1/2061.

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South Milton Ley is a small coastal wetland in Southern England. A sand-bar forms periodically at its seaward end and separates fresh water from the sea. The common reed Phragmites australis dominates the wetland and when a sand bar is present a shallow freshwater lake forms. Monthly water budgets were prepared for the years 1994, 1995 and 1996 and intermittent flooding of the Ley was also monitored. This information was used to calculate a range of residence times (between one hour and eleven days) and the characteristics of various flow regimes when the sandbar, which dams the Ley, is open or closed. Reed growth and the lake's ecology are potentially influenced by effluent from a sewage treatment works (STW) that discharges into the wetland. Water chemistry and hydrology of the wetland have been studied alongside experiments to investigate any effects of nutrient enrichment from the STW on reed growth. Inflowing and outflowing waters were analysed in order to determine concentrations of total oxidised nitrogen (TON), total dissolved nitrogen (TDN), soluble reactive phosphorus (SRP), total dissolved phosphorus (TDP) and potassium (K). Over the study period the annual load of SRP to the Ley increased from 3.65 gmˉ² aˉ¹ in 1992 to 8.1 gmˉ² aˉ¹ in 1996. TON load rose from 69.35 g mˉ² aˉ¹ in 1992 to 104.8 g mˉ² aˉ¹ in 1996. K fell from 97.3 g mˉ² aˉ¹ in 1994 to 96.4 g mˉ² aˉ¹ in 1996. The STW uses a Reedbed Treatment System (RBTS) to 'polish' its final effluent. The efficiency o f the RBTS was studied and during 1996 the efficiency rate for T ON was 20.9% and for SRP was 9.3%. Measurements of height, diameter, numbers of internodes, density and biomass of reeds collected from South Milton Ley were undertaken during August 1994 and 1995. Results of analyses for 1994 indicate that reeds were thinner and possessed fewer seedheads than those of 1995 but that density was greater. Reed fieldwork during 1994 found that height, diameter, numbers of internodes, biomass and number of seedheads were greater below the STW than above. During 1995 only seedhead production was greater below the outlet. The wettest area of the Ley contained reeds with greatest height and diameter. The driest area produced a higher density of reed growth. Laboratory experiments suggested that low N:K ratios and high P:K produced taller plants. Data from reed fieldwork together with results from hydrology and water chemistry studies were used in a statistical analysis in order to determine which, if any of these factors caused changes in reed growth. A conclusive link between water chemistry, hydrology and plant variables was not found. Correlation analysis for 1994 indicated that high concentrations of SRP and TON could produce thin reeds with low biomass. Analysis for 1995 suggested that elevated K values could produce a high density of short reeds. Water depth was found to have a significant effect (P < 0.001) on diameter. The key factors for reed decline (high water levels from spring to winter which can inhibit reed regeneration and increase residence times, increasing nutrient loads and changes in the ratio of N:P:K which could alter reed growth) are all present. At its present loading the Ley is nutrient rich and does not appear to be buffering wetland waters. After data analysis and fieldwork was completed a bloom of Oscillatoria sp.occurred at the seaward end of the Ley during August 1999. This, the first know occurrence of a bloom may be an indication that changes in the ecosystem of South Milton Ley are occurring. For the future, a programme of nutrient reduction, hydrological management and growing knowledge of wetland processes may prevent adverse changes.

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27

Sabetraftar, Karim. "The hydrological flux of organic carbon at the catchment scale : a case study in the Cotter River Catchment, Australia /." View thesis entry in Australian Digital Theses Program, 2005. http://thesis.anu.edu.au/public/adt-ANU20070502.141450/index.html.

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28

Connor, Sarah. "Movement of nitrogen through a riparian forest in a tropical, agricultural landscape." Thesis, Dijon, 2012. https://researchonline.jcu.edu.au/28286/1/28286_Connor_2012_thesis.pdf.

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Riparian zones have been widely reported to function as effective buffers, removing nitrate (NO₃⁻) from groundwater before it is discharged into adjacent streams. This is particularly important in agricultural catchments where additional nitrogen (N) from fertilisers may be leached into groundwater. On coastal plains, NO₃⁻ in groundwater discharged into streams can potentially enrich coastal waters. The permanent removal of NO₃⁻ through denitrification can improve water quality, however incomplete denitrification produces nitrous oxide (N₂O), a greenhouse gas. Despite copious research in temperate regions, little study has been conducted on the capacity of riparian zones to remove NO₃⁻ from groundwater in the tropics. In agricultural areas of the Australian humid tropics, annual rainfall is high, around 3000 mm, and wet and dry seasons are clearly defined. Wet seasons are characterised by rainfall of high intensity and duration, followed by a dry season producing sporadic small amounts of rainfall. The overarching questions of this thesis are: in an agricultural landscape in the humid tropics, is NO₃⁻ in groundwater removed as it enters a forested riparian zone and is transported towards the stream? And, are there temporal and spatial differences in patterns of N₂O emissions produced from the riparian forest? This research is focused on a forested riparian zone 150 m wide, located amongst sugarcane fields, on the coastal plain adjoining the World-Heritage listed Great Barrier Reef lagoon, in the Australian humid tropics. To gain an understanding of the movement of groundwater through the riparian site, the hydrology of the riparian zone was characterized using measurements of soil water content and water table depth (13 piezometers). In the wet season the system was highly dynamic with large fluctuations in water table levels and long-term inundation of low lying areas. Rapid water table rises were attributed to high in-situ recharge, low air-filled pore space (unsaturated zone), air entrapment and occasional recharge from the creek, and the rapid falls to the steep local hydraulic gradients. The dry season was characterised by a slow moving system with depth to watertable up to 4 m at high locations. Groundwater entering the riparian zone was found to have low concentrations of NO₃⁻ (mean <0.03 mg NO₃⁻N L⁻¹ over both seasons), however, concentrations increased (by up to 50 fold) as groundwater progressed through the riparian zone, suggesting the riparian zone was a potential source of NO₃⁻ to the adjacent creek. The addition of NO₃⁻ was attributed to nitrification in riparian surface soils, driven by large net primary productivity, including large amounts of litterfall (12.19 Mg ha⁻¹y⁻¹). Nitrate generated in riparian soil was subsequently leached into groundwater in the wet season during rainfall events. Nitrate was also derived from nitrification in groundwater and, potentially, from the mixing of deeper groundwater of higher NO₃⁻ concentrations. The tropical riparian forest is a large emitter of N₂O, with soil emissions ranging from -24 to 657 μg N₂O-N m⁻2 h⁻¹. Emissions were highest in the wet season but not significantly different between sites of high and low elevation. Similarly, there was no effect on emissions from differing amounts of leaf litter accumulated on the soil surface. Based on differences in soil water content, N₂O emissions were attributed to both denitrification and nitrification. Nitrous oxide was also produced at depth, within the unsaturated zone, with concentrations in soil air ranging from. 0.7 to 157 μg N₂O-N L⁻¹. Dissolved N₂O concentrations in groundwater were greatest at 1.5 m depth and correlated well with NO₃⁻ concentrations in groundwater. Laboratory experiments determined that riparian surface soils were clearly a source of N₂O, and that soils had limited capacity to further reduce N₂O to dinitrogen (N₂). Denitrification potential was up to 20 times greater in surface soils than in soils at 0.5 m depth. This study has demonstrated that groundwater leaving cultivated land does not always have high concentrations of NO₃⁻ and that NO₃⁻ concentrations are not necessarily reduced during the passage of groundwater through riparian forest. Nitrate generated within the riparian zone, on the other hand, was leached into groundwater during heavy rain events and became a potential source of NO₃⁻ to the creek at our site. Similarly, nitrification and denitrification processes within the forested riparian zone contributed substantial N₂O emissions to the atmosphere, similar in range to emissions reported for other tropical forests. Although there are many environmental benefits to having healthy riparian forest, this study in a humid tropical environment did not show any water quality benefits.

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29

Grover, Samantha Patricia Power, and samgrover1@gmail com. "Carbon and water dynamics of peat soils in the Australian Alps." La Trobe University. Centre for Applied Alpine Ecology, School of Life Sciences, 2006. http://www.lib.latrobe.edu.au./thesis/public/adt-LTU20070627.172842.

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This research investigated carbon dynamics, water dynamics and peat formation at Wellington Plain peatland in the Victorian Alps. The properties of bog peat and dried peat were measured, and the ensuing results are outlined below. The carbon chemistries of both bog peat and dried peat displayed changes with depth consistent with an increase in the extent of decomposition of the organic material. Representative changes in the alkyl:O-alkyl ratio down the profile were 0.14 to 0.96 for bog peat and 0.28 to 1.07 for dried peat. Laboratory incubations on the influence of chemistry, particle size, water content and sample preparation indicated that, in the absence of confounding factors, peat chemistry was the most important factor in determining the size of the mineralisable carbon pool. Water content was the most important factor in determining the rate of carbon mineralization. In the field, both bog peat and dried peat emitted an average of 2 g CO2/m2/d from the surface. Carbon mineralisation was related to both soil temperature and soil water content, and this relationship was used to model peat mineralisation under a range of possible future climate scenarios. Below the surface, however, I measured lower rates of decomposition in the dried peat than in the bog peat. The water-holding capacity of peat was measured in the laboratory, as was the rate of water movement through peat. Specific yield decreased down the profile in both bog peat (0.88 to 0.45 cm3/cm3) and dried peat (0.36 to 0.11 cm3/cm3). Hydraulic conductivity also decreased down the profile in both peats: 5.1x10-4 to 3.0x10-6 m/s in bog peat, and 1.0x10-4 to 7.0x10-6 m/s in dried peat. Relationships between the hydrologic properties of peat and its physical and chemical properties were identified. In the field, fluctuations in the watertable were monitored in concert with rainfall. These laboratory and field measurements enabled me to develop models of the hydrology of bog peat and dried peat. Radioisotope dating indicated that both bog peat and dried peat began forming around 3300 years ago. The bog peat appeared to have drained to form dried peat between 131 and 139 years ago. Since that time, erosion appeared to have contributed more to the loss of organic material from dried peat than carbon mineralisation had.

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30

Connor, Sarah. "Movement of nitrogen through a riparian forest in a tropical, agricultural landscape." Thesis, Dijon, 2012. http://www.theses.fr/2012DIJOS104/document.

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Les zones riveraines sont connues pour fonctionner comme des tampons efficaces, capable d’éliminer les nitrates des eaux souterraines avant leur rejet dans les ruisseaux adjacents. Ce rôle de tampon est particulièrement important dans les bassins versants agricoles où, l’azote supplémentaire, provenant des engrais, peut être lessivé dans les eaux souterraines. Sur les plaines côtières, les nitrates présents dans les eaux souterraines puis déchargés dans les ruisseaux peuvent potentiellement enrichir les eaux côtières. La transformation des nitrates par le processus de dénitrification permet d’améliorer la qualité de l'eau, cependant, la dénitrification incomplète produit du protoxyde d’azote (N2O), un gaz à effet de serre. Bien qu’un grand nombre de recherches aient été menées dans les régions tempérées, peu d'études ont été conduites dans les régions tropicales sur la capacité des zones riveraines à éliminer les nitrates des eaux souterraines. Dans les zones agricoles de la région tropicale humide en Australie, les précipitations annuelles sont élevées, autour de 3000 mm, et les saisons humides et sèches sont clairement définies. La saison humide se caractérise par des précipitations de forte intensité et de longue durée, suivie par une saison sèche définie par de faibles précipitations sporadiques. Les questions fondamentales de cette thèse sont les suivantes: dans un paysage agricole tropical humide, les nitrates contenus par les eaux souterraines, sont-ils éliminés lors de leur passage dans une zone boisée riveraine avant d’être transportés vers le ruisseau ? Observe- t-on des différences temporelles et spatiales des flux de N2O émis par les sols de la forêt riveraine ?Cette étude se focalise sur une zone riveraine boisée, d’une largeur de 150 m, située au milieu des champs de canne à sucre, sur la plaine côtière adjacente à la lagune de la Grande Barrière de corail (inscrite au patrimoine mondial), localisée dans la région tropicale humide d'Australie.Pour acquérir une compréhension du mouvement des eaux souterraines sur le site riverain, l'hydrologie de la zone a été caractérisée par des mesures de la teneur en eau du sol et par la profondeur de la nappe phréatique (13 piézomètres). Durant la saison humide, le système était très dynamique, avec de grandes fluctuations des niveaux de la nappe phréatique et, à long terme, l’inondation des zones basses. Les rapides hausses de la nappe phréatique ont été attribuées à une recharge in situ élevée, au faible volume d’air contenu dans les pores (zone non saturée), au piégeage de l'air et à la recharge occasionnelle de la crique. Les baisses rapides de la nappe phréatique ont été attribuées aux importantes différences de hauteur au sein de la zone riveraine, différences dues, partiellement, à la topographie vallonnée du site. La saison sèche a été caractérisée par un système lent, avec une profondeur de nappe phréatique pouvant atteindre 4 mètres dans certains endroits. Les eaux souterraines arrivant dans la zone riveraine contenaient de faibles concentrations de nitrates (moyenne <0.03 mg NO3- N L-1 durant les deux saisons). Cependant, les concentrations ont augmenté (jusqu'à 50 fois) lors de la progression des eaux souterraines à travers la zone riveraine, suggérant que la zone riveraine était une source de nitrates pour le ruisseau adjacent. L'augmentation de nitrates a été attribuée à la nitrification ayant lieu dans les sols riverains de surface, processus favorisé par une importante productivité primaire nette, notamment de grandes quantités de litière (12.19 Mg ha-1 an-1). Par la suite, les nitrates générés par le sol riverain ont été lessivés dans les eaux souterraines par les précipitations, durant la saison humide. Ainsi, les nitrates dans les eaux souterraines proviennent de la nitrification et, potentiellement, du mélange avec des eaux souterraines profondes ayant des concentrations supérieures en nitrates. [...]
Riparian zones have been widely reported to function as effective buffers, removing nitrate (NO3-) from groundwater before it is discharged into adjacent streams. This is particularly important in agricultural catchments where additional nitrogen (N) from fertilisers may be leached into groundwater. On coastal plains, NO3- in groundwater discharged into streams can potentially enrich coastal waters. The permanent removal of NO3- through denitrification can improve water quality, however incomplete denitrification produces nitrous oxide (N2O), a greenhouse gas.Despite copious research in temperate regions, little study has been conducted on the capacity of riparian zones to remove NO3- from groundwater in the tropics. In agricultural areas of the Australian humid tropics, annual rainfall is high, around 3000 mm, and wet and dry seasons are clearly defined. Wet seasons are characterised by rainfall of high intensity and duration, followed by a dry season producing sporadic small amounts of rainfall. The overarching questions of this thesis are: in an agricultural landscape in the humid tropics, is NO3- in groundwater removed as it enters a forested riparian zone and is transported towards the stream? And, are there temporal and spatial differences in patterns of N2O emissions produced from the riparian forest?This research is focused on a forested riparian zone 150 m wide, located amongst sugarcane fields, on the coastal plain adjoining the World-Heritage listed Great Barrier Reef lagoon, in the Australian humid tropics. To gain an understanding of the movement of groundwater through the riparian site, the hydrology of the riparian zone was characterized using measurements of soil water content and water table depth (13 piezometers). In the wet season the system was highly dynamic with large fluctuations in water table levels and long-term inundation of low lying areas. Rapid water table rises were attributed to high in-situ recharge, low air-filled pore space (unsaturated zone), air entrapment and occasional recharge from the creek, and the rapid falls to the steep local hydraulic gradients. The dry season was characterised by a slow moving system with depth to watertable up to 4 m at high locations.Groundwater entering the riparian zone was found to have low concentrations of NO3- (mean <0.03 mg NO3-N L-1 over both seasons), however, concentrations increased (by up to 50 fold) as groundwater progressed through the riparian zone, suggesting the riparian zone was a potential source of NO3- to the adjacent creek. The addition of NO3- was attributed to nitrification in riparian surface soils, driven by large net primary productivity, including large amounts of litterfall (12.19 Mg ha-1 y-1). Nitrate generated in riparian soil was subsequently leached into groundwater in the wet season during rainfall events. Nitrate was also derived from nitrification in groundwater and, potentially, from the mixing of deeper groundwater of higher NO3- concentrations [...]

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31

Son, Kyongho. "Improving model structure and reducing parameter uncertainty in conceptual water balance models with the use of auxiliary data." University of Western Australia. School of Environmental Systems Engineering, 2006. http://theses.library.uwa.edu.au/adt-WU2006.0094.

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[Truncated abstract] The use of uncertainty analysis is gaining considerable attention in catchment hydrological modeling. In particular, the choice of an appropriate model structure, the identifiability of parameter values, and the reduction of model predictive uncertainty are deemed as essential elements of hydrological modelling. The chosen model structure must be parsimonious, and the parameters used must either be derivable from field measured data or inferred unambiguously from analysis of catchment response data. In this thesis, a long-term water balance model for the Susannah Brook catchment in Western Australia has been pursued using the ?downward approach?, which is a systematic approach to determine the model with the minimum level of complexity, with parameter values that in theory are derivable from existing physiographic data relating to the catchment. Through the analysis of the rainfall-runoff response at different timescales, and the exploration of the climate, soil and vegetation controls on the water balance response, an initial model structure was formulated, and a priori model parameter values estimated. Further investigation with the use of auxiliary data such as deuterium concentration in the stream and groundwater level data exposed inadequacies in the model structure. Two more model structures were then proposed and investigated through formulating alternative hypotheses regarding the underlying causes of observed variability, including those associated with the absence of a contribution of deep groundwater flow to the streamflow, which was indicated by deuterium concentration and internal dynamics characterized by the observed groundwater levels. ... These differences are due to differences in the time delay between rainfall and recharge between upland and riparian regions. The ages of water recharging the groundwater and discharging from the catchment were estimated by assuming a piston flow mechanism. In the deeper, upland soils, the age of recharging water was considerably larger than the unsaturated zone delay would suggest; a recharge response 16 days after an infiltration event may involve water as much as 160 days old. On the other hand, the delay and the age of recharging water were much lower in the shallow riparian zone. Where the upland zone contributes significantly to discharge, the predicted difference between the rainfall-discharge response time and the average age of discharging water can be significant.

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32

Whiting, Julian Peter. "Identification and modelling of hydrological persistence with hidden Markov models." 2006. http://hdl.handle.net/2440/37842.

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Hydrological observations are characterised by wet and dry cycles, a characteristic that is termed hydrological persistence. Interactions between global climate phenomena and the hydrological cycle result in rainfall and streamflow data clustering into wetter and drier states. These states have implications for the management and planning of water resources. Statistical tests constructed from the theory of wet and dry spells indicate that evidence for persistence in monthly observations is more compelling than at an annual scale. This thesis demonstrates that examination of monthly data yields spatially - consistent patterns of persistence across a range of hydrological variables. It is imperative that time series models for rainfall and streamflow replicate the observed fluctuations between the climate regimes. Monthly time series are generally represented with linear models such as ARMA variants ; however simulations from such models may underestimate the magnitude and frequency of persistence. A different approach to modelling these data is to incorporate shifting levels in the broader climate with a tendency to persist within these regimes. Hidden Markov models ( HMMs ) provide a strong conceptual basis for describing hydrological persistence, and are shown to provide accurate descriptions of fluctuating climate states. These models are calibrated here with a full Bayesian approach to quantify parameter uncertainty. A range of novel variations to standard HMMs are introduced, in particular Autoregressive HMMs and hidden semi - Markov models which have rarely been used to model monthly rainfall totals. The former model combines temporal persistence within observations with fluctuations between persistent climate states, and is particularly appropriate for modelling streamflow time series. The latter model extends the modelling capability of HMMs by fitting explicit probability distributions for state durations. These models have received little attention for modelling persistence at monthly scale. A non - parametric ( NP ) HMM, which overcomes the major shortcomings of standard parametric HMMs, is also described. Through removing the requirement to assume parametric forms of conditional distributions prior to model calibration, the innovative NP HMM framework provides an improved estimation of persistence in discrete and continuous data that remains unaffected by incorrect parametric assumptions about the state distributions. Spatially - consistent persistence is identified across Australia with the NP HMM, showing a tendency toward stronger persistence in low-rainfall regions. Coherent signatures of persistence are also identified across time series of total monthly rainfall, numbers of rain - days each month, and the intensities of the most extreme rain events recorded each month over various short durations, illustrating that persistent climate states modulate both the numbers of rain events and the amount of moisture contained within these events. These results provide a new interpretation of the climatic interactions that underlie hydrological persistence. The value of HMMs to water resource management is illustrated with the accurate simulation of a range of hydrologic data, which in each case preserves statistics and spell properties over a range of aggregations. Catchment - scale rainfall for the Warragamba Reservoir is simulated accurately with HMMs, and rainfall - runoff transformations from these simulations provide reservoir inflows of lower drought risk than provided from ARMA models.
Thesis (Ph.D.)--School of Civil and Environmental Engineering, 2006.

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33

Whiting, Julian Peter. "Identification and modelling of hydrological persistence with hidden Markov models." Thesis, 2006. http://hdl.handle.net/2440/37842.

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Abstract:

Hydrological observations are characterised by wet and dry cycles, a characteristic that is termed hydrological persistence. Interactions between global climate phenomena and the hydrological cycle result in rainfall and streamflow data clustering into wetter and drier states. These states have implications for the management and planning of water resources. Statistical tests constructed from the theory of wet and dry spells indicate that evidence for persistence in monthly observations is more compelling than at an annual scale. This thesis demonstrates that examination of monthly data yields spatially - consistent patterns of persistence across a range of hydrological variables. It is imperative that time series models for rainfall and streamflow replicate the observed fluctuations between the climate regimes. Monthly time series are generally represented with linear models such as ARMA variants ; however simulations from such models may underestimate the magnitude and frequency of persistence. A different approach to modelling these data is to incorporate shifting levels in the broader climate with a tendency to persist within these regimes. Hidden Markov models ( HMMs ) provide a strong conceptual basis for describing hydrological persistence, and are shown to provide accurate descriptions of fluctuating climate states. These models are calibrated here with a full Bayesian approach to quantify parameter uncertainty. A range of novel variations to standard HMMs are introduced, in particular Autoregressive HMMs and hidden semi - Markov models which have rarely been used to model monthly rainfall totals. The former model combines temporal persistence within observations with fluctuations between persistent climate states, and is particularly appropriate for modelling streamflow time series. The latter model extends the modelling capability of HMMs by fitting explicit probability distributions for state durations. These models have received little attention for modelling persistence at monthly scale. A non - parametric ( NP ) HMM, which overcomes the major shortcomings of standard parametric HMMs, is also described. Through removing the requirement to assume parametric forms of conditional distributions prior to model calibration, the innovative NP HMM framework provides an improved estimation of persistence in discrete and continuous data that remains unaffected by incorrect parametric assumptions about the state distributions. Spatially - consistent persistence is identified across Australia with the NP HMM, showing a tendency toward stronger persistence in low-rainfall regions. Coherent signatures of persistence are also identified across time series of total monthly rainfall, numbers of rain - days each month, and the intensities of the most extreme rain events recorded each month over various short durations, illustrating that persistent climate states modulate both the numbers of rain events and the amount of moisture contained within these events. These results provide a new interpretation of the climatic interactions that underlie hydrological persistence. The value of HMMs to water resource management is illustrated with the accurate simulation of a range of hydrologic data, which in each case preserves statistics and spell properties over a range of aggregations. Catchment - scale rainfall for the Warragamba Reservoir is simulated accurately with HMMs, and rainfall - runoff transformations from these simulations provide reservoir inflows of lower drought risk than provided from ARMA models.
Thesis (Ph.D.)--School of Civil and Environmental Engineering, 2006.

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34

Thomas, Geoffrey Anthony. "Sources and chemical evolution of salts on the Australian continent." Phd thesis, 1995. http://hdl.handle.net/1885/115386.

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This research investigates how the sources of salts in surficial waters and their chemical evolution are influenced by: distance inland from the coast, catchment lithology, catchment hydrology, climate, and agricultural and human activity. This project involved eight study areas in Australia: Acraman and Lake Eyre in South Australia, Yeelirrie and Disappointment in Western Australia, Natimuk and Colac in Victoria, Buchanan in Queensland and Kulgera in the Northern Territory. The hydrochemistry of surficial waters sampled from the eight study areas indicates that both marine aerosol and rock weathering are predominant hydrochemical processes that contribute to the chemical composition of these surficial waters. The ³⁶C1 and ³⁴S isotope hydrochemistry data indicate that the marine aerosol is the principal source of chloride and sulphate in surficial waters. The rock-weathering component is most evident from the Na/Cl, K/Cl, Mg/Cl, Ca/Cl and HCO₃/CI chemical ratios and the alkali and alkaline earth normative carbonate salts of dilute waters - in terms of their departure from a marine hydrochemistry and a marine salt norm, respectively. The chemical ratios and salt norms for the surficial waters also reveal that the highly-modified marine hydrochemistries for dilute groundwaters chemically evolve to hydrochemistries for saline waters which are marine-like (are similar to marine chemical ratios, and have vestiges of the halite-carnallite-bischofite-anhydrite-keiserite-magnesite marine salt norm). However, the trend in Cl/Br, Na/Cl, K/Cl, Mg/Cl and Ca/Cl chemical ratios (from dilute to saline waters) and the presence of complex alkali and alkaline earth normative sulphate salts in saline waters indicates that rock-weathering reactions (such as calcite and dolomite dissolution and ion-exchange reactions) have contributed solutes at early stages in the chemical evolution of these waters. As these waters chemically evolve, their hydrochemistry evolves in response to additional hydrochemical processes (such as carbonate-, gypsum- and halite-formation and ion-exchange reactions). The presence of clays in near-surface strata in all study areas contributes to the gradual decrease in cationic ratios (Na/Cl, K/Cl, Mg/Cl and Ca/Cl) due to ion-exchange reactions as dilute groundwaters chemically evolve to saline waters with marine-like hydrochemistries. The effect that ion exchange has on the chemical evolution of surficial waters is most evident for K+ ions. The findings of this project indicate that in the Colac study area, lake systems with the same basement lithologies but which have significantly different catchment hydrologies and hence significantly different groundwater contributions also have distinctly different hydrochemistries. This distinction is especially evident in the K/Cl ratios of their lake waters. In the more temperate study areas (Natimuk, Colac and Buchanan), the chemical precipitation of Ca- and Mg-bearing carbonates from surficial waters also decreases their Ca/Cl, Mg/Cl and HCO₃/CI ratios with increasing salinity. However, in the more arid study areas (Yeelirrie, Acraman, Kulgera, Disappointment and Lake Eyre), calcretes and other soil carbonates have formed in drainage channels. The formation of dolomite is also common in these calcretes. Groundwaters flowing through such calcrete deposits commonly chemically evolve to have Ca/Cl and Mg/Cl ratios higher than those in waters of similar Total Dissolved Solids (TDS) in the more temperate study areas. The presence of near-surface marine sediments within a catchment (as for the Natimuk and Colac study areas) is also a potential source of Ca²+ and Mg²+ ions to groundwaters from their re solution of calcite and dolomite in the marine sediments. In semi-arid and arid regions, gypsum is also commonly present in lake systems. Re-solution of this gypsum results in surficial waters having high Ca/Cl and SO₄/CI ratios compared to the marine hydrochemistry. This effect is most evident in the dilute to saline surficial waters in the Yeelirrie and Acraman study areas and in parts of the Natimuk study area (prior to halite saturation). In these study areas there is a significant presence of gypsum in the near-surface lithology, and biogenic sulphate reduction has a minimal impact on the pool of sulphate ions. However, in the more temperate study areas (Buchanan, Colac and in parts of Natimuk), where there is a more limited source of sulphate ions, biogenic sulphate reduction is the predominant hydrochemical process. The low Mg/Cl ratios of Buchanan and Lake Eyre saline waters are largely attributed to the formation of palygorskite (a Mg-rich clay mineral). The high pH of the saline Buchanan lake waters, the high silica content of inflowing groundwaters and the sub-tropical semi-arid Buchanan climate are considered appropriate environmental conditions for the formation of palygorskite in lake deposits over approximately the last 1.6 Ma. Even though the palygorskite present in the Etadunna Formation at Lake Eyre formed during the Oligocene to the Miocene, the formation of palygorskite is likely to account for the significant depletion of magnesium in the saline waters of Lake Eyre and its subsurface brines. The hydrochemistries of very saline waters in the arid study areas are significantly affected by halite crystallization and halite re-solution. Their relative predominance increases as a function of the aridity of the study area. A halite-deficient (hypersaline) component in near-surface Yeelirrie and Acraman groundwaters in arid study areas with no record of marine sediments is also suggested from the hydrochemistries of their groundwaters. However, a hypersaline and dolomitic diagenetic characteristic of certain groundwaters in the temperate study areas, where marine sediments occur in the near- surface strata (Natimuk and Colac), suggests that these groundwaters have acquired a marine connate component from re-solution of pore waters entrapped in the marine sediments. Although, the hydrogen and oxygen isotope hydrochemistry reveal that the waters in these aquifers are meteoric, there is hydrochemical and hydrogeological evidence in the Natimuk and Colac study areas to suggest that saline marine connate pore waters may be released from the weathering of marine sediments present in these groundwater systems. This investigation has shown, from the hydrochemistry of lake waters in the more arid study areas, that bromide enrichment is indicative of hypersalinity. However, in the near-surface Yeelirrie and Acraman groundwaters, bromide enrichment may also occur by degradation of soil organic matter. Conversely, under different environmental conditions (such as experienced in the sub-tropical Buchanan study area), it is possible that bromide uptake by the biomass results in bromide depletion in near-surface waters. The high nitrate concentration of groundwaters in the arid study areas has been attributed to biogenic sources in the near-surface soils and the lack of denitrifying activity. However, in the more temperate study areas, agricultural and human activity are responsible for low levels of nutrients in surficial waters. The sulphur isotope hydrochemical data for the Australian continent suggest that close to the coast there is a significant sea-salt component in rainfall and marine aerosols. These data also suggest that along most of the east, west and south coasts of mainland Australia there is a significant non-sea salt sulphate (largely DMS-derived) component. However, the sea-salt sulphate component of the marine aerosol decreases with increasing distance inland. The sulphate component in marine aerosols, which reach the arid interior of Australia, is mostly of non-sea salt sulphate origin. This investigation, involving the hydrochemistry of surficial waters from eight study areas widely distributed in Australia, has clearly shown that climate, catchment lithology, catchment hydrology, distance inland from the coast, and agricultural and human activity are important factors in determining the sources of salts in surficial waters and their chemical evolution on the Australian continent.

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35

Lampayan, Rubenito M. "Groundwater hydrology and modelling of the Jemalong and Lake Cowal aquifer systems, Lachlan Catchment, NSW." Phd thesis, 2001. http://hdl.handle.net/1885/147187.

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36

Carlile, Paul William. "A semi-distributed catchment hydrology model for simulation of land use change, streamflow and groundwater recharge." Phd thesis, 2007. http://hdl.handle.net/1885/150350.

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37

Schreider, Sergei Yulievich. "Large scale modelling of hydrologic response for climate impact assessment and flood forecasting." Phd thesis, 1996. http://hdl.handle.net/1885/144313.

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38

Chen, Xiang-Yang. "Lake Amadeus, Central Australia : modern processes and evolution." Phd thesis, 1989. http://hdl.handle.net/1885/109327.

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Lake Amadeus, a large saline piaya 120 km long and up to 12 km wide, forms a major feature of arid Central Australia. Surrounded by stabilized dunefields, it has been selected here as the site for a range of historic and process oriented studies. The Amadeus piaya is today a groundwater controlled system of a type largely unrepresented by detailed studies elsewhere in Australia. Moreover, it lies in an area from which Late Cenozoic environmental data remain sparse. With its associated variety of stabilized gypsum and quartz dunes associated with saline sedimentary facies, it provides sensitive indicators of past arid depositional events. Analyses of the stratigraphic and chronologic record are supplemented by detailed studies of modern hydrologic, chemical and sedimentary processes. These provide the framework controls within which interpretations of the past record are reconstructed. Field work was carried out during winter and spring seasons in 1984, 1985 and 1986. Four 15m cores and more than 20 short cores up to 1.7m long were taken. Across the piaya and its marginal land, groundwater, shallow stratigraphy and sediments were studied by piezometers, trenches and auger holes. Evaporation was measured with a method of sediment blocks. Palaeomagnetism and thermoluminescence dating methods were used to establish the piaya chronology. Thin section, chemical, mineral and texture analyses help in evaluation of the sedimentary facies assemblage. The Cenozoic sediments are divided into two major units: Uluru Clay in lower part and the overlying Winmatti Beds. The Uluru Clay sequence, at least 60m thick, overlies Proterozoic dolomitic limestone. Of uniform lithology, it consists of clay horizons with minor intercalated gypsum. The Clay was deposited in a shallow lacustrine and fluvial enviroument with periodical saline and frequently dry conditions. The basal Uluru Clay is estimated to be over 5 Ma old. The transition from Tertiary to Quaternary, coincident with the Gauss/Matuyama palaeomagnetic boundary, occrred within the uniform Uluru Clay sequence. The Winmatti Beds comprise the top several metres of basin sediments. The beginning of Winmatti Beds coincides probably with Jaramillo subchrone (0.91 Ma). The appearance of gypsum-clay laminae, thick gypsum sands and aeolian quartz, characteristic of the Winmatti Beds, marks the onset of a new sedimentary and climatic environment. In this the dominance of saline groundwater marks the first development of a groundwater discharge playa system. The association with aeolian deposits signals the dominance for the first time of major aridity. On the landward margin, two rings of gypseous dunes and associated quartz dunes represent facies equivalent of arid units in the playa. The older gypseous dune possibly formed soon after the Uluru Clay. The younger gypseous dune is correlated with a gypseous clayey sand layer within the Winmatti Beds. The gypseous dunes were deposited by deflation of near-shore gypsum accumulating in the groundwater seepage zone during a period of high watertable. The hydrologic and climatic history since the younger gypseous dune formation is correlated broadly with events identified in Southern Australia. The younger gypseous dune formed around 45 to 60 Ka B.P. (TL dates), when a high regional watertable was associated with a wetter climate. A period of regional dune activation followed the younger gypseous dune formation resulting in an aeolian sand deposit in the playa and the thick quartz sand mantle on the gypseous dunes. This represents a drier and windier period which may correlate with the low water level period of 25 to 16 Ka in Southern Australia. The deposition of shallow water gypsum layer, which comprise marginal terraces and low terrace islands, represents a relatively high water level period. This may correlate with the relatively high water levels of Holocence time in Southern Australia. The chronology and stratigraphy predating the younger gypseous dune remain unclear. They are complicated by major breaks in the depositional record. Groundwater bevelling, deflation and soil formation help explain the hiatuses and low rates of deposition. A new surface feature is identified which has both morphologic and stratigraphic expression. Termed GYPSUM GROUND it comprises a large area of the playa surface. A brown undulating salt encrusted surface developed over a nearly pure layer of sand-sized gypsum lies some 40 cm above the local watertable and above the level of periodic annual flooding. Thin section and detailed sedimentologic studies establish this as a degradational remnant of a previously more extensive gypsum sand associated with a high watertable environment equivelant to the deposition of gypsum marginal terraces and low terrace islands. The gypsum ground, now largely independent of groundwater evaporative processes, is one of three morphologic and sedimentary units recognized as characterising the modern playa surface. The other two at lower surface altitude, salt flat and sulphide lowland, are controlled by a combination of groundwater and surface interactive processes. Evaporation pattern for the playa surface are divided into two types. One represents a very low rate from the encrusted surface (El phase); the other is a much higher evaporation phase after the crust is dissolved by rain (E2 phase). Evaporation of the El phase is estimated to be of the order 70mm/y. Since all rain water is not totally evaporated during the E2 phase, this value (El) can only be used as an upper limit for net evaporation, the difference between the total evaporation and the rain water on the surface. The quantity of rainfall not evaporated during E2 phase (therefore a recharge component) seems to be significant compared to the annual El evaporation. Therefore, the net evaporation and discharge rate may be very low, consistent with a very low salt concentration rate in the system. This evaporative regime provides new insights into the question of evaporite formation in a context where the absence of salts seems anomalous when considered in the light of present processes. The playa lacks any substantial salt deposits (other than gypsum and glauberite), either on the surface or in the sediment column, eventhough it has been experienced saline conditions. The surficial salt crusts are commonly 1 cm thick and never exceed 5 cm although the watertable remains in the capillary fringe and the groundwater is highly saline (250g/l). The total quantity of dissolved salts in the groundwater pool are less than expected from present processes considering the long existence of the saline phase. The thin salt crusts on the surface today are ephemeral being subject to periodic dissolution and reformation. Crusts cannot develop to a significant thickness because of combined low net evaporation, leaching by.rainfall, possible downward ionic diffusion associated with groundwater body unsaturated with respect to sodium chloride. Groundwater salinity has probably never exceeded chloride saturation due to a combination of processes including slow chemical concentration rates, processes of groundwater body expansion, past salt loss through deflation and salt leakage by deep groundwater outflow during early Quaternary or even Tertiary time. The priciple of simplistic uniformitarian interpretations is once more called into question by these studies. In its Quaternary hydrologic history, the groundwater discharge playa, today delicately balanced between discharge and recharge regime, has sometimes existed as a prolonged groundwater recharge zone as evidenced by fossil soils with vegetative biotubule remnants. Thus the present hydrologic processes are not representative of past regimes emphasizing the dangers of using modern processes as analogues for past regimes. The data confirm that Lake Amadeus has rarely operated as a true surface water lake since Tertiary time. The groundwater processes and history demonstrated here provide a new basis for understanding playa systems both here and in comparable arid to semi-arid regions of low relief elsewhere in the world.

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Cheshire, Katherine Jane-Maree. "Larval fish assemblages in the Lower River Murray, Australia: examining the influence of hydrology, habitat and food." Thesis, 2010. http://hdl.handle.net/2440/64118.

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The major assumption of currently accepted fish recruitment hypotheses (e.g. flood pulse concept and flood recruitment model) is that in the absence of overbank flows the main river channel does not provide adequate food and habitat for larvae and juveniles. However, periods of low flows are common throughout floodplain rivers, and there are a wide diversity of life history strategies exhibited by riverine fish. Therefore, the broad applicability of these assumptions to the management of all fish species and floodplains rivers has been questioned. The low flow recruitment hypothesis pioneered the concept that some fishes can successfully spawn and recruit during low flows by utilising main channel habitats. Characteristics of the river channel, flow regime and level of regulation are often distinctly different both within and between rivers, and many of the recruitment models and indeed the life history strategies of fishes, remain untested in alternative floodplain river systems. River regulation has resulted in altered flow regimes in river systems throughout the world, and in turn, has a range of negative impacts on the fish populations. The Murray-Darling Basin is Australia’s largest river catchment and has been severely affected by river regulation. To test some of the assumptions of the previously described recruitment models larval fish and zooplankton sampling was conducted in the main channel environments of the Lower River Murray, South Australia. In comparison to the rest of the Murray-Darling Basin, the Lower River Murray is unique due to the combination of four distinct geomorphologic regions, the absence of significant tributaries, and the high degree of regulation. Extensive river regulation has drastically reduced the natural flow variability of the Lower River Murray. Furthermore, there has been little work on the spawning and larval assemblages within this region. Larval fish sampling is often used for studying the early life history of fishes, but sampling gear and diel timing of sampling can bias results. Pelagic plankton tows were the single most effective method for collection of most species. Diel variation was identified for many species; with most exhibiting higher abundances during the night, although one species occurred in higher abundances during the day. Given these results the sampling regime for this project utilised both day and night pelagic plankton tows. Annual differences in the larval assemblages in relation to variations in hydrology and environmental variables were investigated across four years, including a year of increased flow and a water level raising, and three years of low regulated flow with stable water levels. The main channel environment of the Lower Murray supported larvae from all life history strategies. The larval assemblage differed between years; the flow pulse year was consistently different from the subsequent three low flow years. Three responses to varying hydrology were identified in the larval assemblage: larvae that were 1) positively correlated to increased flow, 2) negatively correlated to the increased flow and 3) correlated to temperature. The low flow recruitment hypothesis was supported, with a number of smallmedium bodied native species spawning under low flow conditions in the river channel. However, golden perch and silver perch (flow cued spawners), were only present during the flow pulse year. Environmental flows are therefore vitally important for the management and restoration of some native fish species. Strong within year variability was inherent in the data due to the seasonal variation in spawning time of fishes. The timing of peak spawning in the Lower River Murray was compared to other studies throughout the Basin. The broad spawning patterns identified for individual species were similar to seasonal spawning guilds identified for Australian species in previous studies. These spawning guilds were spring/summer and summer spawners. Understanding the timing of spawning of key species within a region will ensure that management actions can be targeted at providing benefits for species of interest. The key assumption of many recruitment models is that the main river channel is an area of low productivity, and therefore it does not provide adequate food for developing larvae, which is particularly pronounced in years of low flow. Zooplankton sampling was conducted during the spring/summer of 2006 in the pelagic zone of the main river channel in a typical low flow year. Although temporally and spatially restricted, results indicated that during a low flow year an abundant prey source does exist in the main river channel in the Lower River Murray. Furthermore the prey was abundant in the pelagic zone of the open water, where traditionally pelagic zooplankton abundances have been documented to be relatively low. This suggests that in the absence of floodplain inundation developing larvae have adequate access to food in this lowland temperate system. The inundated floodplain is generally recognised as important habitat for developing, larvae, consequently the importance of the main channel environment is frequently overlooked despite many studies highlighting the importance of shallow, still littoral zones. Larval fish were sampled in three main channel habitats: backwaters, open water and still littoral zones. Larvae of key species successfully spawned and utilised these main channel habitats during a low flow year. Specifically, still littoral zones and backwaters were important main channel habitats for developing fish larvae, providing support for the applicability of the low flow recruitment hypothesis to the Lower River Murray. Some species (namely the small – medium bodied natives were able to spawn and recruit in the Lower River Murray under low flow conditions, but these were also able to spawn under the higher flow conditions. However, during the low flow years there were no larvae golden perch or silver perch collected, suggesting that these species were not spawning under the low flow conditions. This study has highlighted that a number of species will spawn and develop as larvae in the heavily regulated weir pool environment. In addition, adequate food and habitat were available for developing fish larvae in the absence of floodplain inundation in the Lower River Murray. However, for species with specific flow requirements (such as golden perch and silver perch, and potentially Murray cod and freshwater catfish) continued low flow conditions may pose a significant threat. In heavily regulated systems, environmental water allocations should be considered to manage and potentially restore declining fish populations, and the benefit of within channel flow pulses should not be underestimated.
Thesis (Ph.D.) -- University of Adelaide, School of Earth and Environmental Sciences, 2010

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Gallant, John Christian. "Pesticide transport models for assessing nonpoint source pollution in Australia." Master's thesis, 1992. http://hdl.handle.net/1885/144088.

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Whan, Kirien Rebecca. "Interactions between large-scale modes of climate variability that influence Australian hydroclimatic regimes." Phd thesis, 2014. http://hdl.handle.net/1885/156262.

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Effective management of water resources, including surface and ground water, is vital and relies on a thorough understanding of climatic and hydrological (or 'hydroclimatic') variability. In Australia hydroclimatic variability is associated with several large-scale climate modes, including remote phenomena such as El Nino - Southern Oscillation (ENSO) and the Indian Ocean Dipole (IOD), and more regional climate indices such as the sub-tropical ridge (STR). Individually, the large-scale climate regimes typically associated with rainfall events are well understood. However, less is known about the interactions between, or combinations of, different large-scale conditions that influence Australian hydroclimatic regimes. These interactions are non-linear so traditional statistical frameworks may be unable to adequately characterise these relationships. Classification and Regression Trees (CART) are well suited to analysing relationships between predictor and response variables, including those based on categorical events, that may be modulated by several predictor variables acting together. By employing a more appropriate and novel statistical method this thesis aims to better understand relationships between large-scale modes of climate variability and Australian hydroclimatic regimes. In this work, tree-based models were used to classify regional Australian rainfall regimes from indices of ENSO, the IOD and the STR, yielding the following conclusions. (1) Interactions between tropical (ENSO, IOD) predictor variables and the STR control the strength of the tropical teleconnection and the influence on regional rainfall regimes in southern Australia. When tropical modes and the STR are in the same phase, rainfall regimes are continent-wide and spatially coherent. However, when indices of climate modes are in the opposite phases, i.e. El Nino combined with low STR intensity, the modulation of the tropical teleconnection by the STR is evident, as rainfall anomalies are confined to the northeast of the continent. (2) The influence of both STR intensity and position on rainfall regimes in southeastern Australia was defined. STR position was crucial for defining two distinct types of "wet" autumns, a "summer-like" ("winter-like") regime when the STR was in a southerly (northerly) position. The summer-like regime occurs at frequencies that have not changed detectably over the instrumental record. However, the frequency of the winter-like regime has declined significantly. In addition, the dry regime defined by high STR intensity has been the most frequent regime in recent years, consistent with the attribution of STR intensity as the main driver of the Millennium Drought. (3) The predictive persistence of relationships between a suite of predictor variables (indices of ENSO, IOD and the STR) and rainfall, upper-layer and lower-layer soil moisture was explored. The predictability of spring rainfall was similar using both random forests (a bootstrapping implementation of CART) and linear regression, suggesting results are not dependent on method. The key result, of possible use in seasonal forecasting, is that, deep soil moisture in spring and summer exhibits significantly more predictability than rainfall and shallow soil moisture, due to the persistence of tropical climate drivers and the removal of high-frequency variability in deep layers by natural temporal smoothing as soil moisture is transferred to deep soil layers.

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Puckridge, James Terence. "The role of hydrology in the ecology of Cooper Creek, Central Australia : implications for the flood pulse concept / Jim Puckeridge." Thesis, 1999. http://hdl.handle.net/2440/19505.

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Copies of author's previously published articles inserted.
Bibliography: leaves 317-359.
xxii, 360 leaves : ill. (some col.), maps (some col.) ; 30 cm.
Examines the generality of the Flood Pulse Concept as a model for the role of flow in large floodplain rivers of all climatic zones and reviews the literature on hydrology-biology relations, with particular reference to the ecology of riverine fish. Using techniques of ordination, clustering and analysis of similarities (ANOSIM), examines the relations between flow variability, econology and climate in large rivers worldwide. Using a fie-year database for Cooper Creek in Central Australia, relates structures of fish, macroinvertebrate and zooplankton assemblages and indices of fish health and behaviour to hydrology at several spatial and temporal scales. These relations are established using multivariate techniques, univariate correlation and regression, and neural networks modelling.
Thesis (Ph.D.)--University of Adelaide, Dept. of Zoology, 1999

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Bell, Micah. "Forecasting extreme ENSO events and the associated hydrological impact in eastern Australia." Thesis, 2015. http://hdl.handle.net/1959.13/1059810.

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Research Doctorate - Doctor of Philosophy (PhD)
This research presents ENSO forecasting and explores ENSO impact by investigating climate and catchment forcing on hydrological response (streamflow). Climate is used as a donor input into catchment types both similar to, and substantially different from the original catchment type. This approach allows catchment response in ENSO phases to be explored with and without implicit climate differences. Research outcomes are: Reliable forecasting (by reducing false positive predictions); That climate is dominant over catchment characteristics in driving hydrological response; That catchment groups have implicit climate differences; The action of La Nina and IPO increasing flood risk, is through increased frequency/duration of events, not increased rainfall intensity

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Gehrig, Susan L. "The role of hydrology in determining the distribution patterns of invasive willows (Salix) and dominant native trees in the lower River Murray (South Australia)." Thesis, 2010. http://hdl.handle.net/2440/61314.

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This thesis explores the hydrological factors that may contribute to the observed distribution patterns of invasive willows (Salix) and native trees (Eucalyptus camaldulensis, E. largiflorens and Acacia stenophylla) along the Lower River Murray (LRM) in southern Australia. An initial survey, establishing the diversity and flowering biology of Salix taxa was carried out to ascertain the extent of invasion, and the likelihood of hybridisation, which may accelerate invasion. S. babylonica, S. fragilis, S. × chrysochoma and S. × rubens occur in the study region, each represented by a single gender. None were present on floodplains, but the most dominant taxon, S. babylonica, occurred along the entire length of the main channel. No seed or seedlings were observed; hence reproduction is likely to be asexual. More detailed survey work was then carried out to characterise the distribution patterns of the dominant S. babylonica and co-occurring natives (Eucalyptus camaldulensis, E. largiflorens and Acacia stenophylla) along a hydrologic gradient produced by the extensive weir system in the LRM. In weir pools, variation in daily water levels of weir pools is low (± 0.1 m) immediately upstream of the weir, but higher immediately downstream (0.2-1.0 m daily). The distribution of natives was uniform across weir pools, while S. babylonica was more abundant above weir structures, suggesting low tolerance to variable water regimes. Hypotheses relating to the observed distribution patterns were then tested experimentally on juveniles of the S. babylonica, E. camaldulensis and A. stenophylla. The experiment was carried out in outdoor ponds using an orthogonal design, with four elevations in relation to water level (-25 cm, 0 cm +25 cm, + 50 cm) under each of three water regimes. Experimental water regimes manipulated the magnitude of daily water level changes (static, 0 m dayˉ¹ ; moderate, ± 0.05 - 0.15 m dayˉ¹; high, ± 0.2 -0.5 m dayˉ¹) to mimic typical hydrological conditions across weir pools in the LRM. Final biomass and mean relative growth rates (S. babylonica, 0.0403 ± 0.002 g mˉ²dayˉ¹ A. stenophylla, 0.0249 ± 0.0017 g m ˉ² dayˉ¹; E. camaldulensis, 0.0204 ± 0.0016g mˉ² dayˉ¹) of all 3 species were unaffected by water regimes (i.e. water fluctuations), but were affected by elevation. Survival of both S. babylonica and A. stenophylla was lowest at low elevations where inundation was high. At higher elevations (+25 cm, +50 cm) the RGR of S. babylonica juveniles was much higher than the native juveniles. To test if the persistence of adults of each species along hydrologic gradients were associated with differing tolerances to water deficits and water use characteristics, S. babylonica and native species were examined under typical hydrological conditions in the field and during an unusual drawdown. S. babylonica occurring at the lowest elevations on riverbanks, had the least negative predawn shoot water potential (ψpredawn), followed by the natives, which were at higher elevations. A. stenophylla had the lowest stable carbon isotope ratio (δ¹³C) values (by 1.7 ‰) on the riverbank; suggesting more profligate water use than S. babylonica and E. camaldulensis. However, all riverbank trees had significantly less negative ψpredawn and lower δ¹³C than native trees on floodplains, consistent with higher water availability on riverbanks. The position and stable oxygen isotope ratio (δ¹⁸O) values were consistent with riverbank S. babylonica sourcing their water directly from the river or from shallow soil-water sources (<0.25 m). In floodplain habitats, depth to water was > 2.5 m, and groundwater was 5 times more saline (4.97 ± 0.88 dS mˉ¹) than river-water. Native trees with deep roots, the ability to lower water potentials and alter water use efficiencies may be at an advantage in this habitat relative to S. babylonica. Extreme low flows in the LRM, over a 6-month period, provided an opportunity to assess how S. babylonica and E. camaldulensis responded to a river-water drawdown. During the drawdown, river-water levels fell at a rate of ~2 – 2.5 mm dayˉ¹ and dropped to a minimum of 0.42 m below the designated pool level. S. babylonica and E. camaldulensis maintained high ψpredawn across the drawdown period, most likely because riverbank soil water availability was not limited; as depth to water table only decreased marginally (≤0.15 m) and soil water content and soil water potential were high (<1.1 MPa). However, an above average rainfall in February 2003 significantly increased soil water potential in the upper 0.25 m of the riverbank, which correlated with a significant increase in ψpredawn in E. camaldulensis, suggesting they were able to use shallow, precipitation derived soil-water sources whereas S. babylonica were not. Also under hot, dry conditions, S. babylonica had higher transpiration rates and lower instantaneous water use efficiencies than co-occurring E. camaldulensis. This suggests that S. babylonica may consume larger volumes of water per unit leaf area than natives, if access to water is maintained.
Thesis (Ph.D.) - University of Adelaide, School of Earth and Environmental Sciences, 2010

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McPherson, Andrew Adam. "Salt sources and development of the regolith salt store in the upper Billabong Creek catchment, southeast NSW." Phd thesis, 2003. http://hdl.handle.net/1885/148518.

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Ticehurst, Jenifer Lyn. "Hydrological analysis for the integration of tree belt plantations into Australian's agricultural systems." Phd thesis, 2004. http://hdl.handle.net/1885/148558.

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Laffan, Shawn. "Inferring the Spatial Distribution of Regolith Properties Using Surface Measurable Features." Phd thesis, 2001. http://hdl.handle.net/1885/47656.

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The aim of this research is to determine to what extent properties of the regolith may be inferred using only features easily measured from the surface. To address this research question, a set of regolith properties from Weipa, Queensland, Australia, are analysed. The set contains five variables, oxides of Aluminium, Iron, Silica and Titanium, as well as Depth to Ironstone. This last represents the depth of the layer from which the oxides are sampled.¶ The research question is addressed in two ways. First, locations where the properties are related to modern surface hydrology are assessed using spatially explicit analyses. This is done by comparing the results of spatial association statistics using geometric and watershed-based spatial samples. Second, correlations are sought for between the regolith properties and geomorphometric indices of land surface morphology and Landsat Thematic Mapper spectral response. This is done using spatially implicit Artificial Neural Networks (ANN) and spatially explicit Geographically Weighted Regression (GWR). The results indicate that the degree to which regolith properties are related to surface measurable features is limited and spatially variable.¶ ... ¶ The implications of these results are significant for anyone intending to generate spatial datasets of regolith properties. If there is a low spatial density of sample data, then the effects of landscape evolution can reduce the utility of any analysis results. Instead, spatially dense, direct measurements of subsurface regolith properties are needed. While these may not be a direct measurement of the property of interest, they may provide useful additional information by which these may be inferred.

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Azadi, Samira. "Hydrologic connectivity and degradation thresholds in semiarid landscapes." Thesis, 2020. http://hdl.handle.net/1959.13/1411266.

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Masters Research - Master of Philosophy (MPhil)
The vegetation of dryland landscapes is particularly sensitive to climatic and/or anthropogenic pressures. Land degradation can cause simultaneous structural and functional changes in dryland ecosystems such as increased runoff, increased landscape, and soil resource heterogeneity, decreased secondary production and physiognomic changes. The amount and spatial arrangement of vegetation cover are closely linked to the process of resource redistribution. Disturbances, such as overgrazing and harvesting activities, can disrupt the original spatial structure of vegetation. Vegetation removal can generate increased overland flow and promote leak out of natural resources from the ecosystem by increasing landscape hydrologic connectivity. Thus, changes in vegetation cover can have profound effects on structural hydrologic connectivity and functionality of the landscape. In order to study the ecohydrologic responses of drylands and the effects of land degradation on these ecosystems, a combined structural-functional approach is needed. Thus, the main objective of this research is to investigate the structural and functional responses of dryland ecosystems to land degradation due to anthropogenic disturbances. Due to the wide variety of patterns they display, mulga landscapes provide an ideal setting for case studies aimed at investigating the spatial organization of dryland vegetation. This study was carried out in four study sites within two regions located on the central portions of Mulga (Acacia aneura) range distribution and Mulga lands bioregion in eastern Australia (Northern Territory, Lake Mere, Wallen and Croxdale) along a broad precipitation gradient (200- 500 mm/yr). These study sites can be considered as representative examples of Australian grazing rangelands. At each study site, several plots of the identical area but with varying degrees of vegetation disturbances were selected. For each study site, different datasets including daily rainfall and, high-resolution remote sensing products for DEM and vegetation index (NDVI) estimation during the period of 2001- 2013 were acquired to conduct the study. At first, the effects of changes in vegetation cover on the structural hydrologic connectivity due to land degradation were investigated. Then, the effects of these changes on the functional response of Mulga landscapes were estimated.

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Sun, Hua. "Digital terrain modelling of catchment erosion and sedimentation / Hua Sun." Thesis, 1998. http://hdl.handle.net/2440/19387.

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Corrigenda pasted onto front end-paper.
A study was undertaken of erosion and sedimentation in a catchment in South Australia. An erosion and sedimentation model was developed and interfaced with the existing digital terrain models called TAPES-C and THALES, to estimate soil erosion and deposition in Sauerbier Creek catchment.
Thesis (Ph.D.) -- University of Adelaide, Dept. of Civil and Environmental Engineering, 1999?

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Carman-Brown, Kylie. "Following the water: environmental history and the hydrological cycle in colonial Gippsland, Australia, 1838-1900." Phd thesis, 2011. http://hdl.handle.net/1885/151792.

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This thesis explores a new approach to writing the environmental history of settler societies through an explicit focus on ecological processes, as distinct from the more commonly used landscape or geographic units. In this case, I focus upon the hydrological cycle and four key processes that constitute it. The processes are precipitation; flow above and below ground in rivers, creeks and aquifers; stored or still water in lakes, ponds and wetlands; and evaporation. The work examines the impact of the ecological processes that make up the hydrological cycle within the context of the daily life of colonial settlers in the catchment of the Gippsland Lakes in south eastern Victoria, Australia, from the commencement of white colonization in the late 1830s up to the turn of the century. This time period was selected because by 1900, the principal changes which laid the foundation for the Lakes seriously compromised ecological health in the late 1980s and early 1990s were all in place. Inspired by gestalt psychology, it examines the interaction of those processes with settler knowledge of biophysical processes, their religious and cultural beliefs, economic and political forces at work in their world, work and leisure time, their language and expressions, values and aspirations for themselves and their families. Each of these aspects informed their perceptions of the ecology around them, and particularly, their perception of the significance of water. The findings confirms the critical importance of cultural values, generated through myth, story and action, to understanding environmental changes. Colonial Gippslanders were committed to: a belief in progress, or alternately, banishing wilderness; a belief that the world was made by God for human benefit; and the desire for certainty versus the actual uncertainty in hydrological conditions. Collectively, colonial Gippslanders believed in progress as much as they believed in God, believed themselves largely separate from nature and plumped for certainty. They set to re-plumbing the catchment to eliminate, as far as possible within their technical capabilities, the natural variations within the hydrological cycle. The tools which they applied to achieve this radical re{u00AD}plumbing included the application of engineering knowledge, supported by increasing amounts of technology and machinery and by sophisticated socio{u00AD}political lobbying.

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Dissertations / Theses on the topic 'Hydrology – Australia'

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