Dissertations / Theses on the topic 'Rivers Australia Management'

This thesis provides baseline information on the ecological processes involved in the recruitment and regeneration of riparian vegetation. As there has been a paucity of basic ecological studies on riparian vegetation in Australia, the project is broad in scope, and gives a general picture of the factors influencing, the regeneration of riparian vegetation and provides a starting point for more detailed work. The project focuses on factors determining recruitment events and the life history traits of particular species in a river in the cool temperate zone of south western Australia (Blackwood River) and on a river in the dry tropics of the Kimberley region of north-western Australia (Ord River). By studying two contrasting river systems in different climatic zones, the influence of the physical environment and biotic factors in vegetation persistence and recruitment in the riparian zone can be distinguished. This will contribute to providing an ecological basis for the rehabilitation and management of riparian vegetation in these types of systems. The structure of the vegetation on the Blackwood River consists of an overstorey dominated by Eucalyptus rudis, with a shrub understory at ungrazed sites and with annual species dominant in areas grazed by livestock. On the Ord River there is a much more diverse overstsorey and a species-poor understorey dominated by perennial grasses. Fencing to exclude stock, or to at least manage grazing, is a fundamental step towards achieving rehabilitation of degraded riparian sites where recruitment may be severely limited. Exclosure experiments in the Blackwood River show little improvement in recruitment after three years, with only minor increases in the occurrence and cover of native species. Establishment of these species may be difficult with the increase in abundance of exotic grasses and annual herbs which has occurred as a result of the absence of grazing. These results are however for the short-term and a much longer period is required to look at the vegetation dynamics and successional processes of these sites. In the riparian zone, regeneration of the vegetation from soil seedbanks is important for annual species of herbs and grasses but of only minor significance for perennial species. For perennial species, particularly the overstorey, direct seedfall from existing vegetation occurs, and enhanced dispersal by floating downstream with flood debris is a consequential recruitment mechanism. Hence, reproductive phenology of the four species monitored in this study appears to be well adapted to the hydrological regime on the respective rivers. Position in the riparian landscape where seedlings manage to establish is strongly related to environmental conditions that provide adequate moisture but protect seedlings from flooding. Historical flow records can be used to develop an understanding of the natural flow regime for a particular river which can then be related to patterns of vegetation development in terms of reproductive phenology, seedling establishment and population structure, as well as plant community patterns in the riparian zone. Variability in natural flow regimes, as a disturbance, can therefore be used in conjunction with other abiotic and biotic factors in developing a model of vegetation dynamics for the riparian zone. For example, the regime of intermittent high frequency large flood disturbances on the Ord River prevents the establishment of stable states of the vegetation and the ecosystem is characterised by long periods of transition between short-lived stable states. This riparian ecosystem is thus driven by physical (allogenic) processes rather than by vegetation successional (autogenic) processes. In contrast, lower energy seasonal flooding on the Blackwood River allows mature stands of trees to develop throughout the river profile. Recruitment is continual, although species can also respond to large flood events. This disturbance regime results in long periods of stable status with short periods of transition. The vegetation is thus subject to longer periods of autogenic processes and, because of lower frequency flooding disturbance, shorter periods of allogenic processes. These results highlight the effect of the different fluvial regimes of the two rivers on the respective vegetation dynamics. Management of the riparian vegetation should therefore take into account the frequency and rate of change in the vegetation and that disturbed states and long periods of transition between states, particularly on the Ord River, are part of the natural process. This would suggest that altering the natural flow regimes, such as through river regulation, would have significant effects on riparian vegetation dynamics. This work has relevance to all aspects of riparian zone vegetation, including management of natural systems unaffected by man-made disturbances, for systems affected by stock grazing, for areas requiring rehabilitation and on regulated rivers. It highlights the importance of fluvial processes to riparian vegetation and indicates that understanding the natural flow regime of a target river is a critical first step in the management of riparian vegetation and in the planning of riparian vegetation zone rehabilitation. Where the riparian zone is highly modified, through, for example, livestock grazing and/or weed invasion, natural regeneration of the riparian vegetation may be a long term process. If intervention, such as replanting, is appropriate, care should be taken that species selected are adapted to particular site conditions, such as flooding regime, landscape position and river geomorphology.

[Truncated abstract] This ethnoecological study examines land uses by modern Martu Aboriginal people on their country. They occupy very remote settlements—Parnngurr, Punmu and Kunawarritji—in the Great and Little Sandy Deserts. In 1990, their country included Crown Lands and Rudall River National Park. The study investigated the proposition that the knowledge and practices of Martu were of direct relevance to ecosystem processes and national park management. This research commenced in the wider Australian research context of the late 1980s – early 90s when prevailing questions were about the role of customary harvest within contemporary Aboriginal society (Altman 1987; Devitt 1988) and the sustainability of species-specific harvests by Australian indigenous people (Bomford & Caughley 1996). Separately, there was a national line of enquiry into Aboriginal roles in natural resource and protected area management (Williams & Hunn 1986; Birckhead et al. 1992). The field work underpinning this study was done in 1986–1988 and quantitative data collected in 1990 whilst the researcher lived on Martu settlements. Ethnographic information was gathered from informal discussions, semi-structured interviews and participant observation on trips undertaken by Martu. A variety of parameters was recorded for each trip in 1990. On trips accompanied by the researcher, details on the plant and animal species collected were quantified. Martu knowledge and observations of Martu behaviour are interpreted in terms of the variety of land uses conducted and transport strategies including vehicle use; the significance of different species collected; socio-economic features of bush food collection; spatio-temporal patterns of foraging; and, the 'management' of species and lands by Martu. The research found that in 1990, hunting and gathering were major activities within the suite of land uses practiced by Martu. At least 40% of trips from the settlements were principally to hunt. More than 43 animal species and 37 plant food species were reported to be collected during the study; additionally, species were gathered for firewood, medicines and timber artefacts. Customary harvesting persisted because of the need for sustenance, particularly when there were low store supplies, as well as other reasons. The weight of bush meats hunted at least equalled and, occasionally, was three times greater than the weights of store meats available to Parnngurr residents. ... Paradoxically, hunting was a subject of significant difference despite it being the principal activity driving Martu expertise and practice. There is potential for comanagement in the National Park but it remains contingent on many factors between both Martu and DEC as well as external to them. The dissertation suggests practical strategies to enhance co-management.

Over the last decade, restoration ecology has been considered a new paradigm for dealing with many of the environmental problems of river systems. It is also recognized that management decisions have a greater chance of being successful if they are based on a thorough understanding of a concept or a plan. A review of current studies on river restoration and river restoration planning revealed that managers and scientists have put a substantial emphasis on ecological science and technology in restoration, while many sociopolitical and economic elements have been de-emphasized Besides this, understanding and experiences of river restoration, especially those of river managers and communities, is not well known so far. This study commenced with the development of a framework for river restoration planning, based on a review of current knowledge of river restoration and planning processes. The framework was then used as an instrument to be compared with the understanding and experiences of river managers in two different countries. The aim of this study was to highlight the differences in acceptability of river restoration and river restoration planning between two different river systems in two different countries, and develop a framework for river restoration planning that includes these differences. Using a heuristic inquiry, administrators responsible for two rivers, the Kalgan River in southwest Western Australia and the Liao River in northeast China, were interviewed to test if managers have comparable understandings of river restoration. This study revealed that the understanding of the river restoration concept among never managers who participated in this research is influenced by socio-political, economic and ecological perspectives. For example, in Australia, managers see river restoration according to the kind of ecological benefits people will derive from it. To maintain the sustainable development of the river system is the main goal of river restoration In contrast. In China, river managers would like to put more efforts on maintaining the balance between social, economic and ecological development, although, in the short term, pollution control is the first crucial step for river management. The study also indicated that planning is influenced by different understandings of the concept of river restoration, by the existing administrative structures for river management, and by public participation in river management planning. For example, public participation plays an important role in river restoration planning in Australia, while in China, public participation was not considered appropriate or practical in the formulation of a plan even though more and more managers recognize its need and significance. The final result of this study, a framework for river restoration planning, will supply some basic management guidelines for river managers. Future research can be conducted by using data from a project river to put the results of this study into practice, where case studies can be examined to test the robustness of the framework.

This study has contributed to the development of the reference condition approach in disturbed landscapes. The reference condition approach has been an important development for the bioassessment of aquatic ecosystems by providing a practical tool for the accurate assessment of river condition. The selection of appropriate reference sites is critical to the success of the predictive model in terms of being able to distinguish between natural variation in biota and the effects of human disturbance. Capturing natural variability and explaining it is a key difference between the reference condition approach and other study designs (e.g. before/after/control/impact). Natural disturbances such as drought or bushfire can significantly alter the ecological condition of streams, and although the ecological condition of streams affected by natural drought or bushfire is part of the natural cycle, this natural variation of the ecological condition is rarely incorporated into many study designs because of a mismatch in time scales. Human disturbance has also significantly altered the condition of landscapes through the development of agriculture and urbanisation. In urban or agricultural landscapes it can be impossible to locate streams that have not been modified by human activity for use as a reference condition. This study looked at the effects of natural disturbance on the reference condition, in terms of the way natural disturbance affects the prediction of stream condition and also the incorporation of the condition of streams experiencing natural disturbance into a predictive model. Additionally this study identified an alternative benchmark for modified landscapes based on the presence of good management practices for river protection, and tested this benchmark for the assessment of streams impacted by urbanisation. Drought and bushfire regularly disturb aquatic ecosystems in Australia, and affected reference sites in the ACT and South Coast region of New South Wales in 2002 and 2003. Drought and bushfire conditions affected macroinvertebrates and environmental variables across these streams, and the majority of sites were assessed as significantly impaired using regional AUSRIVAS (AUstralian RIVers Assessment System) models. This indicated the existing reference conditions for these regions had not incorporated the ecological conditions of reference sites suffering these natural disturbances. Many of the environmental variables used to predict the condition of streams were also affected by drought or bushfire. The changes to environmental variables affected how sites were assessed in models, but the overall assessment was not significantly changed from the initial assessment that drought or bushfire had significantly impaired the ecological condition. To reduce potential assessment errors associated with changes to predictor variables an attempt was made to construct new models with changeable variables excluded. However, it was not possible to completely exclude these types of variables, and subsequent models were no better than the original models in terms of changes to predictor variables affecting the generation of expected taxa lists. The changes to environmental variables did not affect the actual assessment of site condition because although group membership probabilities were changed the probabilities of taxon occurrence did not change significantly. The different reference site groups all contained some common taxa that occurred at most sites and even when group probabilities changed this did not change the probability of these taxa occurring at a test site. For regional models, such as the ACT or NSW South Coast, changes to predictor variables may not significantly affect the assessment of site condition. Incorporating reference sites under drought conditions into a predictive model was an effective way of discriminating the effects of drought from human disturbance. The model only provided two different ecological conditions, a single drought measurement and a single non-drought measurement, so the model did not fully encompass the potential natural variability. The model has value as a starting point and was effective in distinguishing sites affected by human disturbance from sites affected by drought. Good Management Practice (GMP) for river protection is any intervention that minimises human impact on stream condition. Urban sites protected by GMP were used as an alternative benchmark to a minimally impacted reference condition. The criteria used to select reference sites were not sufficiently robust to detect a significant benefit of GMP on physical or chemical characteristics of protected sites, compared to sites without GMP. In general however, the physical and chemical condition of GMP sites was better than sites without GMP and there were significant differences in macroinvertebrate assemblages of GMP and non-GMP sites. A refinement to the site selection process is proposed to include a specific assessment of GMP effectiveness for the protection it is designed to provide. This will substantially improve the robustness of a GMP benchmark and provide a clearer picture of the factors controlling biota in urban streams protected by GMP. The GMP benchmark was developed into a predictive model for the assessment of urban stream health, and in terms of the assessment of test site condition, it did not differ significantly from a model using minimally impacted sites. The purpose of the GMP benchmark was to provide an alternative reference condition for the assessment of stream health in modified landscapes when minimally impacted sites are unavailable or provide an unattainable benchmark. The GMP reference condition as an alternative can provide an attainable and realistic benchmark. The development and application of the suggested site selection protocol will improve the robustness of the GMP benchmark and better account for natural variation in the biota and physical characteristics of the sites used to determine the reference condition.

The Australian and New Zealand Environment and Conservation Council (ANZECC) and the Agriculture and Resource Management Council of Australia and New Zealand (ARMCANZ) have announced that the 1997 review of the Australian Water Quality Guidelines will include for the first time, consideration of sediment quality guidelines. For this reason, it is timely to review the methods for establishing such guidelines, and the manner in which they could be used in managing the quality of sediments in Australian rivers, lakes and drainage systems. In this thesis, the problem of the development of sediment quality guidelines is introduced and basic questions relating to the development of such guidelines are addressed. The importance of sediment monitoring and sediment quality assessment in aquatic ecosystem management is demonstrated, and the role of sediment quality guidelines in the process of sediment quality assessment is discussed. The arguments considered in this thesis are illustrated by specific reference to the setting and use of sediment quality guidelines for heavy metal contamination. A number of physico-chemical factors (grain size distribution, pH, redox potential, alkalinity and hardness, salinity, organic matter) can affect the bioavailability and toxicity of contaminants in sediments, and these factors may vary spatially and temporally within and between sediment deposits. Changes in physico-chemical conditions as a result of natural or anthropogenic processes may lead to major changes in bioavailability of sediment contaminants. The variability of these physico-chemical factors has ramifications for the way in which sediment quality guidelines are derived and used. Factors affecting the way in which toxicity is measured (test species chosen, toxicological end-point measured, duration of test relative to life-cycle), and toxicity data is interpreted, are also important to the development of useful sediment quality guidelines. All of these factors must be taken into account in deriving sediment quality guidelines for Australian conditions. The large number of factors affecting the sensitivity and efficiency of sediment quality guidelines means that a simple set of numerical guidelines, as has been used in the past, is not appropriate. A multi-step assessment procedure will be required. Methods of setting sediment quality guidelines that have been used by authorities in overseas jurisdictions were reviewed. Advantages and disadvantages of the various methods were compared. None of the methods used overseas has been shown to be applicable to Australian conditions. In the absence of a suitable method for deriving Australian sediment quality guidelines in the short term, the adoption of the Canadian Interim Sediment Quality Guidelines as interim sediment quality guidelines for Australia is recommended. Sediment quality guidelines need to be viewed in the context of the overall environmental management process, of which they form an integral part. The policy background to environmental management in Australia, and the management frameworks that have been put in place to implement the policy, are outlined. The AS/NZS/ISO 14000 series of standards for environmental management systems provides a framework which is consistent with the principles and objectives of environmental management in Australia. It therefore provides an appropriate framework within which to develop and use sediment quality guidelines. Within the broad AS/NZS/ISO 14000 policy, a framework for the development and use of sediment quality guidelines is proposed, which will provide a technically and legally defensible basis for the management of aquatic sediments in Australia, in the short term and long term. The proposed framework involves the setting of Interim Sediment Quality Guidelines for Australia, based on the best scientific knowledge currently available. The framework recognises that the factors affecting the bioavailability and toxicity of sediment contaminants are complex, and that the current level of knowledge of sediment processes is incomplete. Therefore, a conservative approach to setting guidelines is taken, and a highly sensitive guideline based on that used in Canada, is proposed. The framework further recognises that this approach will lead to over protection of the environment in some cases, so a "Decision Tree" approach is taken. The "decision tree" allows the consideration of more complex interactions than can be incorporated into simple numeric guidelines, while attempting to simplify the assessment process. In keeping with the ISO 14000 series of standards for environmental management, the framework also explicitly includes steps designed to ensure that monitoring data are regularly collated, and analysed, and where necessary, guidelines are able to be updated in light of new knowledge gleaned from the review process. The proposed framework is appropriate to, and supportive of, the principles of environmental management as set out in Australian Government policy documents, inter governmental and international agreements, and legislation. It provides a basis for the on-going collection of data suited to increasing our understanding of the factors influencing the behaviour of contaminants in sediments, and thereby lead to continual improvement in sediment quality guidelines for use in Australian conditions.

Includes bibliographical references (leaves 112-115) Towed DC Resistivity and Transient Electromagnetic arrays have been trialled for suitability in monitoring salt-loads on the Murray River at Waikerie, South Australia.

Doctor of Philosophy(PhD)
It is generally accepted that tree roots can reinforce soil and improve the stability of vegetated slopes. Tree root reinforcement is also recognised in riverbanks although the contribution that the roots make to bank stability has rarely been assessed due to the reluctance of geomorphologists to examine riverbank stability by geomechanical methods that allow for the inclusion of quantified biotechnical parameters. This study investigates the interaction between alluvial soil and the roots of four southeastern Australian riparian trees. It quantifies the amount and distribution of root reinforcement present beneath typically vegetated riverbanks of the upper Nepean River, New South Wales, and examines the effect of the reinforcement on the stability of these banks. The ability of a tree to reinforce the soil is limited by the spatial distribution of its root system and the strength that the roots impart to the soil during shear. These two parameters were determined for the following four species of native riparian tree: Casuarina glauca, Eucalyptus amplifolia, Eucalyptus elata, and Acacia floribunda. The four species all exhibit a progressive reduction in the quantity of root material both with increasing depth and with increasing lateral distance from the tree stem. In the vertical direction there are two distinct zones that can be described. The first occurs from between 0 and approximately 15 % of the maximum vertical depth and consists of approximately 80 % of the total root material quantity. In this zone the root system consists of both vertical and lateral roots, the size and density of which varies between species. The second zone occurs below approximately 15 % of the maximum vertical depth and consists primarily of vertical roots. The quantity of root material in this zone decreases exponentially with depth due to the taper of individual roots. The earth reinforcement potential in terms of both geometric extent and the quantity of root material expressed as the Root Area Ratio (RAR) varies significantly from species to species. E. elata exhibited the highest values of RAR in soil zones beneath it while E. amplifolia reinforced a greater volume of soil than any of the other species examined. The increased shear resistance (Sr) of alluvial soil containing roots was measured by direct in-situ shear tests on soil blocks beneath a plantation. For three of the species (C. glauca, E. amplifolia, E. elata) Sr increased with increasing RAR measured at the shear plane, in a similar linear relationship. The shear resistance provided by A. floribunda roots also increased with increasing RAR at the shear plane but at a much greater rate than for the other three species. This is attributable to A. floribunda’s greater root tensile strength and therefore pull-out resistance, as well as its smaller root diameters at comparative RARs which resulted in a greater proportion of roots reaching full tensile strength within the confines of the test. Tree roots fail progressively in this system. Therefore determining the increased shear strength from the sum of the pull-out or tensile strengths of all individual roots and Waldron’s (1977) and Wu et al’s (1979) simple root model, would result in substantial over estimates of the overall strength of the soil-root system. The average difference between Sr calculated in this manner and that measured from direct in-situ shear tests is 10.9 kPa for C. glauca, 19.0 kPa for E. amplifolia, 19.3 kPa for E. elata, and 8.8 kPa for A. floribunda. A riverbank stability analysis incorporating the root reinforcement effect was conducted using a predictive model of the spatial distribution of root reinforcement beneath riparian trees within the study area. The model is based on measurements of juveniles and observations of the rooting habits of mature trees. It indicates that while the presence of vegetation on riverbank profiles has the potential to increase stability by up to 105 %, the relative increase depends heavily on the actual vegetation type, density, and location on the bank profile. Of the species examined in this study the greatest potential for improved riverbank stability is provided by E. amplifolia, followed by E. elata, A. floribunda, and C. glauca. The presence of trees on banks of the Nepean River has the potential to raise the critical factor of safety (FoS) from a value that is very unstable (0.85) to significantly above 1.00 even when the banks are completely saturated and subject to rapid draw-down. It is likely then that the period of intense bank instability observed within this environment between 1947 and 1992 would not have taken place had the riparian vegetation not been cleared prior to the onset of wetter climatic conditions. Typical ‘present-day’ profiles are critically to marginally stable. The introduction of vegetation could improve stability by raising the FoS up to 1.68 however the selection of revegetation species is crucial. With the placement of a large growing Eucalypt at a suitable spacing (around 3-5 m) the choice of smaller understorey trees and shrubs is less important. The effect of riparian vegetation on bank stability has important implications for channel morphological change. This study quantifies the mechanical earth reinforcing effect of some native riparian trees, thus allowing for improved deterministic assessment of historical channel change and an improved basis for future riverine management.

Thesis (MTech (Environmental Management)))--Cape Peninsula University of Technology, 2011.
A study involving a wetland plant, common reed (Phragmites australis L.) was carried out along the bank of the lower Diep River and the adjacent soil samples from four different sites (Milnerton Lagoon, Lower Estuary, Milnerton Bowling Club and Woodbridge Island), Cape Town, South Africa. The aim was to determine the extent of metal contamination and its impact on physiological indices. Results showed that among the metals evaluated, AI and Fe were consistently higher in all the soil samples (from both river bank and the adjacent soil) followed by Zn, Mn, Pb, Cu, Cd, Co, Cr and Ni. The concentrations of AI in the river banks ranged between 1214.1 - 3176 mg.kg-1 compared with the adjacent soils, where AI concentration ranged from 434.8 - 2445.4 mg.kq". The Fe concentrations from the river bank values ranged from 1136.4 - 4897.2 mg.kg-1 compared with Fe concentrations of the adjacent soil samples which ranged from 402.2 - 2459.8 mg.kg-1 . Generally, Zn ranged from 2.4 - 211.5 mq.kq"; Mn: 5.5 - 48.05 mg.kq': Pb: 0.97 - 71.7 mg.kq"; Cu: 0.3 - 45.9 mg.kq'; Cd: 0.0 - 9.3 mg.kq": Co: 0.2 - 2.7 mg.kq': Cr: 0.3 - 2.1 mg.kg-1 ; and Ni: 0.02 - 2.6 mg.kg-1. Overall, Ni had the lovest concentrations in the ecosystem. Results also showed that the abundance of metals from plant samples were in the order of AI > Pb > Cd > Co > Ni > Cr; and for micronutrients, Fe > Mn > Zn > Cu both in the shoots and roots sampled from all the sites investigated. The values of chlorophylls a, b and total chlorophyll as well as photosynthesis were significantly higher in the P. australis plant samples and from the adjacent soil compared with those from the river bank. These results suggest that contamination of soils and wetland ecosystem by metals over and above plant requirements may affect the chlorophyll and photosynthesis rate of the plant thereby undermining the physiological functioning of plants growing along river systems.

Stormwater is recognised as a transport mechanism for pollutants. Pollutants enter stormwater drains via surface washoff, subsurface flow or direct discharge. Landuse is reported to affect the quantity of pollutants released into stormwater drains. In Australia, the contribution of nutrients (nitrogen and phosphorus) and surfactants from industrial areas to surface drainage is poorly understood. Previous research has mainly focused on the quality of water leaving residential and agricultural areas. In Western Australia, there is growing concern over the health of the Swan-Canning River system, which is seeing signs of eutrophication. Runoff and discharge from residential, commercial, and industrial areas influence the quality of water in the Swan-Canning River system. A study of nutrient release was undertaken for the eastern sector of the Canning Vale Industrial Area, to determine the contribution of industry to nutrient loads received by the Canning River system, between August 2001 and 2002. Data was collected three times a week using a point sampling regime. Diurnal and storm event variability were also tested. Data collected from the eastern sector of the industrial area was compared to that released from the entire Bannister Creek Catchment area. Nitrogen and phosphorus concentrations downstream of industrial areas have been reported at 45mg L-1 and 15mg L-1 respectively (Thomas et al, 1997; John, 2000). In this study, the median concentrations of nitrogen and phosphorus downstream of industry in Bannister Creek, at the Tom Bateman Reserve Detention Basin, were 1.32mg L-1 and 0.11mg L-1 respectively. Concentrations of nitrogen and phosphorus were not indicative of point source discharge. Nutrient concentrations reported in Bannister Creek in this study, have been consistent with data collected and reported in other studies i.e. Donohue et al, 1992 and Jakowyna, 2002. Nitrogen and phosphorus loads released from the entire Bannister Creek Catchment area, exceeded loads previously reported in other studies i.e. Donohue et al ( 1994); Donohue et al, 1992 and Jakowyna, 2002. An estimated 32890kg of nitrogen and 2085kg of phosphorus was released from Bannister Creek Catchment during the study. Rainfall during the study period was reflective of the drying climate Perth has been experiencing over the last ten years. Nitrogen and phosphorus released from Bannister Creek during the study period are likely to be underestimated, as they do not include the data collected for a significant storm event recorded at Hybanthus Road on the 16.4.02. During this 1- 2/1-5 ARI storm event 1586kg of nitrogen and 185kg of phosphorus were exported from Bannister Creek, producing loads ten times greater than that estimated during the point sampling regime. The later values were used in the calculation of annual loads to maintain consistency between the study sites. Despite the significant load of nutrients released from the catchment on 16.4.02, rainfall was not the main transport mechanism for nitrogen and phosphorus, indicated by the weak correlation e.g. R2 > 0.1. Base flow was determined to be the most significant pathway of nutrient export. The concentrations and loads of nitrogen and phosphorus released from the industrial area were low, but the contribution to catchment loading was important. The rate of nutrient release per unit of area was higher from the eastern sector of the Canning Vale Industrial Area than the entire Bannister Creek Catchment Area. Nitrogen was released at a rate of 4163kg km2 yr from the industrial area and 134 2. 86kg km2 yr for the entire catchment. Phosphorus was the same. From the industrial area it was released at a rate of 397kg km2 yr compared to a rate of 94.2kg km2 yr from the entire Bannister Creek Catchment Area. The study revealed the need to retain nutrients within the catchment. Studies on stormwater management suggest that this can be achieved through Water Sensitive Urban Design and Best Management Practices. Both strategies work on the principle of retaining and recycling nutrients within the catchment area. Work is currently been undertaken to meet the objectives of these two management strategies in Bannister Creek. Work has included the removal of the southwestern bank of the Tom Bateman reserve detention basin to create a meandering wetland, and the downgrading of the banks along Bywood Way, Lynwood to create a Living Stream. Further studies should focus on the effectiveness of these strategies.

Human-environment interactions will be profoundly affected by anthropogenic climate change. Coastal communities, dependent on freshwater ecosystems for their livelihoods and cultural practices, are likely to be seriously impacted by rising sea level. For communities already subject to marginalising forces of remoteness, poverty or the legacies of colonisation, climate change impacts will likely compound existing stressors. The freshwater floodplains of the Alligator Rivers Region in the Northern Territory, spanning Kakadu National Park and part of West Arnhem Land, represent such a place. This area is at risk from sea level rise, particularly saltwater intrusion, while also home to Aboriginal Australians continuing to practice customary or subsistence harvesting based on freshwater resources. In seeking to support sustainable adaptation to climate change in this context, this thesis examines Indigenous people’s experiences, in living memory, of responding to past and persisting social-ecological change. A place-based, contextual framing approach was used to examine vulnerability and adaptive capacity. Through semi-structured interviews, trips on country, cultural resource mapping and archival work, contemporary patterns of freshwater resource use and Aboriginal people’s perceptions of changes to their freshwater hunting, fishing and gathering activities (collectively termed ‘harvesting’) were examined. Qualitative models were used to conceptualise factors influencing an individual’s ability to engage in freshwater customary harvesting and the determinants shaping adaptive capacity for customary harvesting. The social-ecological drivers of change in freshwater harvesting practices raised by respondents included: existing threats from introduced animals and plants, altered floodplain fire regimes and the ‘bust then boom’ in saltwater crocodile population following recovery from commercial hunting. These all had implications for sustaining customary harvesting practices including restricting access and the transmission of knowledge. Impacts driven by the introduced cane toad, invasive para grass and saltwater crocodile population change, represent examples of solastalgia, particularly for women’s harvesting practices. In addition to environmental conditions, determinants of adaptive capacity of customary harvesting included; mobility on country- particularly supported through on country livelihoods and outstations, social networks facilitating access and knowledge sharing, health and well-being and inter-generational knowledge transmission. Past experience of saltwater intrusion facilitated by feral water buffalo in Kakadu was examined through the lens of social learning, as a historical analogue for future sea level rise. These experiences were shown to influence contemporary perceptions of risk and adaptive preferences for future sea level rise. Customary harvesting was also found to offer unique opportunities to improve remote Indigenous development outcomes across diverse sectors. To build adaptive capacity supporting freshwater customary harvesting practices in this context it will be essential to; understand historical trajectories of social-ecological change, recognise the potential for diversity within groups- including a gendered analysis of adaptive capacity, address existing social-ecological stressors and foster knowledge collaborations for supporting knowledge transmission, the co-production of knowledge and sustaining social networks. Facilitating a social learning environment will be particularly crucial in supporting local autonomy, leadership and experimental learning, and is particularly beneficial in jointly managed protected area contexts. Most importantly, incorporating local Indigenous knowledge, values, perceptions of change and risk into locally-developed adaptation strategies will be essential in developing more culturally relevant and thus sustainable, adaptation pathways.

This thesis examined the impact of anthropogenic alterations in four riverine catchments of the Eastern Mt. Lofty Ranges, South Australia, to identify if creek restoration via environmental flows is a viable management option and if so, to determine; 1) Whether an aquatic/riparian viable seed bank was present and if so what was its composition 2) The ecological condition of selected riverine reaches. This in combination with the seed bank study would identify those creeks that would most benefit from the imposition of environmental flows 3) The response of key species to the water regimes likely to result from the imposition of environmental flows 4) The influence of nutrient enrichment under a fluctuating water level and to use this information to formulate best practice policy for environmental flows 5) Whether aquatic plants promoted by environmental flows were a significant fraction of the diet for higher trophic levels represented by Trichopterans and Amphipods. The seed banks were of comparable density (ranging from 4,000 to 110,000 seeds m-2) and species richness (ranging from 13 to 20 aquatic / riparian species) to the seed banks of other Australian rivers and wetlands, but this varied significantly among riverine sections and across catchments. Out of a total of 81 species recorded, 51 were classified as terrestrial (63% of all species recorded). What is of greater concern was the number of exotic (both aquatic and terrestrial) species recorded: 43% of the species recorded in the Angas, 47% of the species in the Finniss, 39% of the species in Tookayerta creek and 43% of the species recorded in Currency creek were exotic, which are significantly higher in comparison to other Australian studies. There were 24 to 28 aquatic/riparian species recorded in the extant vegetation of each catchment that were not recorded in their seed banks. Likewise, a number of species (3 to 7) were recorded in each catchments seed bank that were not recorded in the extant vegetation of those catchments. A species of particular interest is Crassula sieberana, which is on the State endangered plant species list. Indices for assessing the ecological condition, health or integrity of a river or riparian habitat were employed to investigate the relationship between the river/riparian habitat and the land and water management practices associated with those habitats. Of the four catchments surveyed, each catchment identified a unique set of site parameters (subindex indicators) that were strongly correlated with its ecological condition. Indicator species analyses revealed pasture grasses to be a significant indicator of reaches in very poor condition (p = 0.0010) along the Finniss and Baumea juncea of those reaches in good condition (p = 0.0230). Along the Angas, Cotula coronopifolia was an indicator of those reaches in average condition (p = 0.0240) and along Currency creek, Cladium procerum was an indicator of those reaches in good condition (p = 0.0190). However, when all 115 surveyed reaches were analysed together, those reaches of average to excellent ecological condition were all strongly correlated (R2 = 0.50) with the subindex indicators: bank stability, % riparian cover, grazing, fenced, aquatic wood, and width of the riparian vegetation. This would indicate that these subindex indicators are the main site parameters determining the ecological condition of a riverine reach and hence its restoration potential. Those catchments or sub-catchments containing a high proportion of reaches classified to be in poor to very poor condition had significantly reduced seed banks. The influence of water level fluctuations (±15 cm, ±30 cm and ±45 cm) on the growth of four species of emergent macrophytes (Cyperus vaginatus, Phragmites australis, Typha domingensis and Triglochin procerum) were species dependent. These species naturally inhabits different zones across the elevation gradient. C. vaginatus, which has a high elevation preference, was strongly inhibited by increasing water depth and fluctuations in water levels. In contrast, species with an intermediate elevation preference, such as Phragmites australis and Typha domingensis, were more tolerant to both depth and water level fluctuations. However, the biomass and relative growth rate (RGR) of T. domingensis and P. australis were depressed when grown under the combination of deep elevation and a highly fluctuating water level (±45 cm). Between the static and ±45 cm amplitude treatments, growth of T. domingensis was inhibited by 52%. The growth of P. australis appeared to be enhanced by fluctuating water levels and only showed a severe drop-off in growth in the deep elevation, ±45 cm amplitude treatment. In C. vaginatus the RGR was dependent of the average emergent surface area (and the implied rate of carbon acquisition)(p<0.0001; r2=0.7196; F=87.276; n=36; RGR (mg g-1 day-1) = -5.096 + 4.313 × ln (Average emergent surface area (cm2)), but this was not the case in P. australis and T. domingensis (p>0.05) even when the photosynthetic canopy was partially inundated by rising water levels. Yet these two species demonstrated different growth rates when grown under different water regime amplitudes and at different elevations. Growth of T. procerum did not respond to either amplitude or elevation, but its RGR remained negative. This suggests that another factor(s) was limiting the growth of P. australis, T. domingensis and possibly T. procerum, a factor that varies with water level. Cyperus gymnocaulos had significantly increased plant performance (p <.0001) with increased nutrient loading rates but this effect was significantly reduced under a fluctuating water regime (p =0.0007). Remarkably, under a fluctuating regime, P. australis had a significant reduction in performance with increased nutrient loading rates (p =0.0013), whereas T. domingensis performance was significantly limited (p =0.034) even with increased nutrient loading rates. T. procerum too had increased plant performance with increased nutrient loading rates but this effect was reduced under a fluctuating regime. The morphological response by T. procerum demonstrates that it is mainly limited by the nutrient loading rates and not the water regime. However, it was significantly limited/reduced by its increased turnover rates caused by a stochastic fluctuating water regime. Illustrating that in fact the effects of nutrient enrichment on T. procerum were independent of water regime but bearing in mind that water regime is the primary factor determining the productivity of this species. For those species with higher elevation preferences, e.g. C. gymnocaulos, or low elevation preference, e.g. T. procerum, the effects of nutrient loading are independent of water regime, whereas those species with an intermediate elevation preference, e.g. P. australis and T. domingensis the effects of nutrient loading are largely dependent on the water regime. Amphipoda and Trichoptera selectively fed on succulent semi-emergent macrophytes across sites of average to excellent ecological condition (31-64% to 65-97% of diet), depending on availability. These semi-emergent macrophytes contained the lowest C:N ratio (≈10:1), closest to that of their consumers (≈5:1) and therefore the highest nutritional content. In degraded riverine reaches, there were limited food resources available, hence course particulate organic matter (CPOM) formed the main dietary components of Amphipoda (20-53% of diet) even though it had the highest C:N ratio (≈40:1). At site VP. 1, filamentous algae was the main dietary component of Trichoptera (48-64% of diet) due to its availability and its low C:N ratio (≈14:1) in comparison to the other primary sources available. The imbalanced consumer-resource nutrient ratios in these degraded riverine reaches are likely to impose constraints on the growth and reproduction of their aquatic shredder communities with probable knock-on effects at higher trophic levels. The installation of environmental flows to restore and promote aquatic/riparian plant communities, which in turn would benefit higher trophic organisms, is a viable and realistic management option along selected reaches. Those selected reaches contain a significant aquatic/riparian seed bank and with sufficient physical habitat remaining to promote their germination and establishment. However, the imposition of environmental flows as a control measure to prevent the colonisation and dominance of particular species (T. domingensis and P. australis) was deemed to be redundant as a management technique given the limited water resources available.
Thesis (Ph.D.) -- School of Earth and Environmental Sciences, 2007

This thesis examined the impact of anthropogenic alterations in four riverine catchments of the Eastern Mt. Lofty Ranges, South Australia, to identify if creek restoration via environmental flows is a viable management option and if so, to determine; 1) Whether an aquatic/riparian viable seed bank was present and if so what was its composition 2) The ecological condition of selected riverine reaches. This in combination with the seed bank study would identify those creeks that would most benefit from the imposition of environmental flows 3) The response of key species to the water regimes likely to result from the imposition of environmental flows 4) The influence of nutrient enrichment under a fluctuating water level and to use this information to formulate best practice policy for environmental flows 5) Whether aquatic plants promoted by environmental flows were a significant fraction of the diet for higher trophic levels represented by Trichopterans and Amphipods. The seed banks were of comparable density (ranging from 4,000 to 110,000 seeds m-2) and species richness (ranging from 13 to 20 aquatic / riparian species) to the seed banks of other Australian rivers and wetlands, but this varied significantly among riverine sections and across catchments. Out of a total of 81 species recorded, 51 were classified as terrestrial (63% of all species recorded). What is of greater concern was the number of exotic (both aquatic and terrestrial) species recorded: 43% of the species recorded in the Angas, 47% of the species in the Finniss, 39% of the species in Tookayerta creek and 43% of the species recorded in Currency creek were exotic, which are significantly higher in comparison to other Australian studies. There were 24 to 28 aquatic/riparian species recorded in the extant vegetation of each catchment that were not recorded in their seed banks. Likewise, a number of species (3 to 7) were recorded in each catchments seed bank that were not recorded in the extant vegetation of those catchments. A species of particular interest is Crassula sieberana, which is on the State endangered plant species list. Indices for assessing the ecological condition, health or integrity of a river or riparian habitat were employed to investigate the relationship between the river/riparian habitat and the land and water management practices associated with those habitats. Of the four catchments surveyed, each catchment identified a unique set of site parameters (subindex indicators) that were strongly correlated with its ecological condition. Indicator species analyses revealed pasture grasses to be a significant indicator of reaches in very poor condition (p = 0.0010) along the Finniss and Baumea juncea of those reaches in good condition (p = 0.0230). Along the Angas, Cotula coronopifolia was an indicator of those reaches in average condition (p = 0.0240) and along Currency creek, Cladium procerum was an indicator of those reaches in good condition (p = 0.0190). However, when all 115 surveyed reaches were analysed together, those reaches of average to excellent ecological condition were all strongly correlated (R2 = 0.50) with the subindex indicators: bank stability, % riparian cover, grazing, fenced, aquatic wood, and width of the riparian vegetation. This would indicate that these subindex indicators are the main site parameters determining the ecological condition of a riverine reach and hence its restoration potential. Those catchments or sub-catchments containing a high proportion of reaches classified to be in poor to very poor condition had significantly reduced seed banks. The influence of water level fluctuations (±15 cm, ±30 cm and ±45 cm) on the growth of four species of emergent macrophytes (Cyperus vaginatus, Phragmites australis, Typha domingensis and Triglochin procerum) were species dependent. These species naturally inhabits different zones across the elevation gradient. C. vaginatus, which has a high elevation preference, was strongly inhibited by increasing water depth and fluctuations in water levels. In contrast, species with an intermediate elevation preference, such as Phragmites australis and Typha domingensis, were more tolerant to both depth and water level fluctuations. However, the biomass and relative growth rate (RGR) of T. domingensis and P. australis were depressed when grown under the combination of deep elevation and a highly fluctuating water level (±45 cm). Between the static and ±45 cm amplitude treatments, growth of T. domingensis was inhibited by 52%. The growth of P. australis appeared to be enhanced by fluctuating water levels and only showed a severe drop-off in growth in the deep elevation, ±45 cm amplitude treatment. In C. vaginatus the RGR was dependent of the average emergent surface area (and the implied rate of carbon acquisition)(p<0.0001; r2=0.7196; F=87.276; n=36; RGR (mg g-1 day-1) = -5.096 + 4.313 × ln (Average emergent surface area (cm2)), but this was not the case in P. australis and T. domingensis (p>0.05) even when the photosynthetic canopy was partially inundated by rising water levels. Yet these two species demonstrated different growth rates when grown under different water regime amplitudes and at different elevations. Growth of T. procerum did not respond to either amplitude or elevation, but its RGR remained negative. This suggests that another factor(s) was limiting the growth of P. australis, T. domingensis and possibly T. procerum, a factor that varies with water level. Cyperus gymnocaulos had significantly increased plant performance (p <.0001) with increased nutrient loading rates but this effect was significantly reduced under a fluctuating water regime (p =0.0007). Remarkably, under a fluctuating regime, P. australis had a significant reduction in performance with increased nutrient loading rates (p =0.0013), whereas T. domingensis performance was significantly limited (p =0.034) even with increased nutrient loading rates. T. procerum too had increased plant performance with increased nutrient loading rates but this effect was reduced under a fluctuating regime. The morphological response by T. procerum demonstrates that it is mainly limited by the nutrient loading rates and not the water regime. However, it was significantly limited/reduced by its increased turnover rates caused by a stochastic fluctuating water regime. Illustrating that in fact the effects of nutrient enrichment on T. procerum were independent of water regime but bearing in mind that water regime is the primary factor determining the productivity of this species. For those species with higher elevation preferences, e.g. C. gymnocaulos, or low elevation preference, e.g. T. procerum, the effects of nutrient loading are independent of water regime, whereas those species with an intermediate elevation preference, e.g. P. australis and T. domingensis the effects of nutrient loading are largely dependent on the water regime. Amphipoda and Trichoptera selectively fed on succulent semi-emergent macrophytes across sites of average to excellent ecological condition (31-64% to 65-97% of diet), depending on availability. These semi-emergent macrophytes contained the lowest C:N ratio (≈10:1), closest to that of their consumers (≈5:1) and therefore the highest nutritional content. In degraded riverine reaches, there were limited food resources available, hence course particulate organic matter (CPOM) formed the main dietary components of Amphipoda (20-53% of diet) even though it had the highest C:N ratio (≈40:1). At site VP. 1, filamentous algae was the main dietary component of Trichoptera (48-64% of diet) due to its availability and its low C:N ratio (≈14:1) in comparison to the other primary sources available. The imbalanced consumer-resource nutrient ratios in these degraded riverine reaches are likely to impose constraints on the growth and reproduction of their aquatic shredder communities with probable knock-on effects at higher trophic levels. The installation of environmental flows to restore and promote aquatic/riparian plant communities, which in turn would benefit higher trophic organisms, is a viable and realistic management option along selected reaches. Those selected reaches contain a significant aquatic/riparian seed bank and with sufficient physical habitat remaining to promote their germination and establishment. However, the imposition of environmental flows as a control measure to prevent the colonisation and dominance of particular species (T. domingensis and P. australis) was deemed to be redundant as a management technique given the limited water resources available.
Thesis (Ph.D.) -- School of Earth and Environmental Sciences, 2007

The primary contributions of this thesis are the economic studies of proposed water use reductions and climate change, and the development of an integrated hydro-economic model for the Murray-Darling Basin, Australia. This water model not only simulates the land and water use in the Basin, but also optimises these uses for certain targets such as environmental flows. More importantly, this model can be applied to evaluate policy options for the Basin, such as water buybacks, and provide estimates of the possible impacts of climate change. The thesis consists of three main essays focusing on issues in water modelling and management in the Basin. The first essay describes the development of a water model. This model is applied to estimate the impacts of water use reductions in the second essay; and climate change in the third essay. Other issues related to the Basin's water management, such as a review of existing water modelling, the background of the Basin, water trading, possible policy implementations and future research are also discussed. The first essay (Chapter 4) describes the construction of the Integrated Irrigated Water Model (IIA WM) including the structure of llA WM and the data sources. Using the latest hydrological data and revised catchment boundaries, llA WM can simulate and optimise land and water use in the Basin. To address the criticism that existing models have failed to consider water trading barriers, the physical constraints on water trading have been incorporated in llA WM. The model can also evaluate various water policies and estimate the impacts of physical condition changes. The second essay (Chapter 5) evaluates the impacts of proposed water use reductions by the Australian government. To balance the use of water between irrigated industries and environmental purposes, the Australian government draft plan released October 2010 proposed to reduce the volume of used water in the Basin from 3,000 to 4,000 GL/year. Simulations from IIA WM indicate that the impacts from proposed water use reductions will be modest, although there may be substantial impacts in particular locations. The third essay (Chapter 6) investigates the impacts of climate change in the Basin. A full range of climate change scenarios from modest to severe have been applied using IIA WM. This thesis finds that with water trading, profit reductions are substantially smaller than the water use reductions.

Research Doctorate - Doctor of Philosophy (PhD)
The impacts of multi-temporal scale climate variability occurring over the Pacific and Indian Oceans on the rainfall and runoff regimes of eastern Australia are explored in this thesis. Three modes of natural climate variability are studied, the El Niño/Southern Oscillation (ENSO), the Interdecadal Pacific Oscillation (IPO) and the Indian Ocean Dipole (IOD). An analysis of historical rainfall and streamflow data for Queensland (QLD), New South Wales (NSW) and Victoria (VIC) reveals strong relationships between indices of ENSO and IPO variability and seasonal rainfall and streamflow totals in the spring and summer months. In addition, it is shown that a strong connection exists between a number of Indian Ocean SST indices and winter rainfall in eastern Australia, offering an improved understanding of year-round seasonal climates. A climate impact assessment is carried out for a regulated irrigation and domestic water supply system located in NSW (the Lachlan River Valley) to determine the main climatic drivers in the region. It is shown that ENSO, the IPO and the IOD have a strong impact on rainfall, evaporation and inflows, while storage volumes, water allocations and sustainable crop areas are also related to the state of ENSO and the IPO. The research presented in this thesis highlights the importance of understanding the role that natural climate variability plays in influencing the climate, water resources and agriculture in eastern Australia. A simple stochastic framework for use in long term drought risk assessment is developed that specially incorporates multi-decadal persistence of rainfall, brought about by changes in the IPO. The drought risk framework is applied to water resource assessment in the Lachlan River Valley, providing greater insight into the frequency, magnitude and duration of hydrological droughts than present approximations that use the limited instrumental record alone. Importantly, the results presented in this thesis highlight the fact that water resource management in eastern Australia must be developed to cope with the full range of natural climate variability, irrespective of future impacts of anthropogenic climate change, to aid in drought proofing our climate sensitive infrastructure.

Copy of author's previously published article inserted. Bibliography: leaves 198-217. This thesis explores the impact of sustained disturbances on the ecology of algal dominated biofilms in the Lower River Murray, South Australia. It focuses on the physical effects of regulation through changes to the light environment and water level regime, and the local effects of grazing. The nutritional signficance of biofilms for the abundant populations of prawns and shrimps in the Lower Murray is also examined.

Copy of author's previously published article inserted.
Bibliography: leaves 198-217.
249 leaves : ill., maps ; 30 cm.
This thesis explores the impact of sustained disturbances on the ecology of algal dominated biofilms in the Lower River Murray, South Australia. It focuses on the physical effects of regulation through changes to the light environment and water level regime, and the local effects of grazing. The nutritional signficance of biofilms for the abundant populations of prawns and shrimps in the Lower Murray is also examined.
Thesis (Ph.D.)--University of Adelaide, Dept. of Zoology, 1997?

A key objective of the Australian National Water Iriitiative of 2004 (clause 23(x)) is that streamwater and groundwater be managed as a single connected system. The National Water Act of 2007 established water sharing plans as a mechanism for ensuring this integrated management of streamwater and groundwater and for driving the sustainable management of Australia's water resources. This thesis investigates streamwater-groundwater interactions in an unconfined alluvial aquifer system in the Widden Brook catchment in the highly productive upper Hunter Valley, eastern Australia. Widden Brook is a right bank tributary of the Goulburn River and contributes up to 17% of flow in the Goulburn. The catchment lithology consists of a basal unit of impermeable Permian carbonaceous shale and coals which is overlain by Triassic Narrabeen sandstone and Tertiary basalts. The aims of this thesis were to reconstruct the hydrological record in the catchment from estimations of the long-term (1913-2007) monthly rainfall, streamflow, baseflow and salt load, reconstructed from records in neighbouring catchments, in order to: (1) recortstruct the long-term hydrological record in the catchment; (2) quantify streamwater-groundwater interactions under changing hydrological conditions; (3) estimate the water balance and the salt balance; and (4) use this data to evaluate the water sharing plan. A record of evapotranspiration was constructed with an established model using spatially interpolated rainfall, evaporation and vegetation coverage in the catchment. Limited stream hydrographs and rating curves were used to estimate long term baseflow and the chloride balance method was used to estimate groundwater recharge. The mean long term (1913-2007) runoff coefficient was 5.4% of rainfall equivalent to 40 mm of specific discharge. Flows however, were highly variable over this period with runoff (specific discharge) of 8.6% (65 mm) and 3.9% (30 mm) for the periods 1950-1979 and 1980-2007 respectively. This decrease in runoff cannot be explained solely by the decrease in rainfall and possible reasons are advanced. The mean estimated annual specific discharge from the reconstructed streamflow record, of 37 mm for the period 1971-2006, was shown to be in good agreement with that predicted using the spatially distributed GROWEST model of 33 mm. Stream salinity in Widden, as measured by electrical conductivity, EC, increases downstream but this is moderated by inputs of freshwater from the tributaries, particularly Blackwater Creek. The relationship between EC and stream flow is used to estimate the salt load discharged by the stream. The mean annual salt load for the period 1913-2007 was 1,813 tonnes/year or a specific salt yield of 3.7 tonnes/km{u00B2} but is highly variable over this period. Estimates of the cyclic salt inputs to the catchment are used to construct a long term salt budget (1913-2007) for the catchment which shows a 29% increase in salt load discharged to streamwater relative to that recharged to the catchment and up to 69% for the flood-dominated period 1950-1979. Estimation of the fraction of the salt load in streamwater at Widden gauge, due to mineral weathering relative to cyclic salt, is in the range 0.17-0.20. There is a distinct relative change in water chemistry downstream. Streamwater chemistry changes from predominantly Na and K ions just below the confluence of Widden Brook and Blackwater Creek, which is associated with kaolinite clay and Na and CI ions in the terrace groundwater, to predominantly Mg and Ca ions in the stream at Emu Creek associated with interstratified illite/smectite exchangeable clays and HC0{u2083}, Mg, Na and CI ions in the groundwater. Strontium isotope ratios are used to show a distinct geochemical signature in groundwater in the older terrace soils which appear disconnected from the stream compared to the younger alluvial floodplain soils which are highly connected to the stream. The hydrochemistry of the groundwater in the terrace in the mid catchment is characterised by higher EC (1500-2200 uS/cm) and oxidising conditions with lower concentrations of soluble iron and higher sulfate concentrations compared to the alluvial floodplain/streamwater which have much lower EC (300-600 ~uS/cm) and mainly reducing conditions, higher concentrations of soluble iron and lower sulfate concentrations. It is shown using geochemistry and water and isotopic tracers that the major sources of salts in the soils, streamwater and groundwater are derived from: (1) evapotranspiration of the shallow groundwater which concentrates salts in the upper soil zone confirmed from CI:Br mass ratios of soil groundwater; (2) mineral weathering of the parent rock material; and (3) ion-exchange reactions in the subsurface clays in the lower catchment. It is inferred that the change in water chemistry in the lower catchment is driven by the strong recharge of streamwater to the aquifer in the losing reach of the catchment which mobilises the Mg and Ca ions in the exchangeable smectite clays in the unconfined groundwater aquifer. The water sharing plan for unregulated catchments in the Hunter Valley is evaluated in light of the above findings. It is found that the information on which the Plan was based is insufficient to ensure sustainability in the system. Suggestions are made for improving the water sharing plan process.

Freshwater ecological systems throughout the world are extensively altered, with threatening processes being physical, chemical and biological. Data is often lacking to describe the processes within the system and their interactions. This thesis explores how modelling can be used to help understand and manage such complex systems under limited data and knowledge, by examining two Australian case studies. The first case study explores how fish species are distributed in the Murray-Darling Basin (MDB), Australia's largest river system, and attempts to understand the variations in fish assemblages across the Basin. The second case study involves the development and evaluation of a habitat suitability model for an endangered species Astacopsis gouldi, the Giant Tasmanian Crayfish. The MDB fish case study adopted a suite of multivariate analysis techniques, including cluster analysis and non-metric multidimensional scaling, which were applied within the framework of a data-mining process, Knowledge Discovery from Data. This is the first known study to describe the large-scale patterns in fish assemblages in the Basin. The analysis identified regions in the Basin sharing similar fish assemblages; these patterns were generally consistent with the temperature, precipitation and elevation of the streams and the temperature and water quality preferences of the species. The delineation of the Basin into regions can be an important basis for future ecological studies, for example by providing context for finer-scale studies or a benchmark for studies examining temporal changes to the fish communities. Bayesian networks were applied to model A. gouldi habitat suitability in the second case study, with a focus on the evaluation process. A series of 18 models were built and tested, based on the same structure but with their parameters estimated from different combinations of expert opinion and training datasets. The data-based A. gouldi habitat suitability models achieved better performance accuracy than the expert models. The combined data- and expert-based models performed equally well as the data-based models but were considered more robust. The model evaluation process revealed interesting insights into the habitat suitability of the species, including that elevation seemed to have little influence on habitat suitability, contrary to other studies. It was also found that the species is not in equilibrium with its environment, suggesting that future models must consider temporal dynamics and avoid using species presence-absence as an indicator of habitat suitability. Both case studies highlighted the subjective nature of modelling and the importance of good modelling practice in producing meaningful and purposeful outputs. Good practice guidelines are provided for Bayesian network modelling, with emphasis on the need of thorough evaluation of the model and its results, and transparent reporting of the modelling process. For models built under limited data and knowledge, it is especially important to acknowledge and embrace the uncertainties. Modelling cannot overcome a lack of data, but can help to integrate information, develop and test hypotheses, and refine knowledge about the system and its processes. Modelling can also help guide future monitoring and research toward data and knowledge gaps most crucial to our understanding of the system.

Most of the lower River Murray and its floodplain wetlands are impacted upon by degradation caused by river regulation. Increasingly the restoration of these ecosystems and the river water quality has become a high priority for federal and state governments and associated departments and agencies. Public concern is adding to the pressures on these departments and agencies to restore these ecosystems and to sustainably maintain the river water quality. The long term monitoring of floodplain wetlands has been limited, compounding the difficulties faced by managers and decision makers on assessing the potential outcome of restoration options. The role of this project in the broad scheme of restoration/rehabilitation is to contribute to the construction of a model capable of increasing managers and decision makers understanding, and build consensus of potential outcomes of management option. This model was to use available data. The developed model, based on WETMOD developed by Cetin (2001), simulates wetland internal nutrient processes, phytoplankton, zooplankton and macrophyte biomass as well as the interaction (nutrient and phytoplankton exchange) between wetlands and the river. The model further simulates the potential impact management options have on the wetlands, and their nutrient retention capacity, and therefore their impact on the river nutrient load. Due to the limitation of data, wetlands were considered in categories for which data was available. Of these two had sufficient data to develop, calibrate and validate the model. Management scenarios for these two wetlands were developed. These scenarios included, the impact of returning a degraded wetland in a turbid state to a rehabilitated clear state, and the impact the removal of nutrient from irrigation drainage inflows has on wetland nutrient retention, and consequent input to the river. Scenarios of the cumulative impact of the management of multiple wetlands were developed based on using these two wetlands, for which adequate data was available, as “exemplar” wetlands, i.e. data from these wetlands were substituted for other similar wetlands (those identified as belonging to the same category). The model scenarios of these multiple wetlands provide some insight into the potential response management may have on individual wetlands, the cumulative impact on river nutrient load and how wetland morphology may relate to management considerations. The model is restricted by data availability and consequently the outputs. Further, some limitations identified during the development of the model need to be addressed before it can be applied for management purposes. However, the model and methods provide a guide by which monitoring efforts can assist in developing future modelling assessments and gain a greater insight not only at the monitoring site but also on a landscape scale.
http://proxy.library.adelaide.edu.au/login?url= http://library.adelaide.edu.au/cgi-bin/Pwebrecon.cgi?BBID=1320131
Thesis (Ph.D.) -- University of Adelaide, School of Earth and Environmental Sciences, 2008

Murray cod Maccullochella peelii peelii is an iconic freshwater angling species that has suffered declines in abundance and is now listed as a nationally vulnerable species. Despite recognition of the need for biological knowledge to provide future management directions, little is known of its ecology. This thesis examines that ecology to provide new knowledge and recommendations for improved conservation management. (For complete abstract open document)

Includes list of publications issued during the candidature.
Bibliography: leaves 176-197.
iii, ix, 197, [22] leaves : ill., maps ; 30 cm.
Title page, contents and abstract only. The complete thesis in print form is available from the University Library.
Phosphorus retention was measured in five pilot-scaled constructed wetlands with different configurations in terms of macrophyte species and substrates in order to evaluate the phosphorus removal efficiency of water plants and substrates in experimental ponds; assess the contribution of macrophytes to phosphorus removal through direct uptake, modification of water chemistry and impacts on the phosphorus adsorption characteristics of substrate; and, contribute to the optimal design and operation of constructed wetlands for the treatment of agricultural drainage water.
Thesis (Ph.D.)--University of Adelaide, Dept. of Soil and Water, 2002?

Includes list of publications issued during the candidature.
Bibliography: leaves 176-197.
iii, ix, 197, [22] leaves : ill., maps ; 30 cm.
Phosphorus retention was measured in five pilot-scaled constructed wetlands with different configurations in terms of macrophyte species and substrates in order to evaluate the phosphorus removal efficiency of water plants and substrates in experimental ponds; assess the contribution of macrophytes to phosphorus removal through direct uptake, modification of water chemistry and impacts on the phosphorus adsorption characteristics of substrate; and, contribute to the optimal design and operation of constructed wetlands for the treatment of agricultural drainage water.
Thesis (Ph.D.)--University of Adelaide, Dept. of Soil and Water, 2002?