School of Earth Sciences - Theses
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ItemLeachate chemistry of two modern municipal waste landfills in Melbourne, Victoria( 1999-11)This study investigates the occurrence and chemical composition of leachate at Clayton South and Brooklyn Municipal waste landfills in Melbourne, Victoria. Both are ‘modern’ municipal waste landfills, being engineered and managed consistent with current regulatory requirements. These landfills accept only putrescible and solid inert waste, but not soluble chemical, hazardous, liquid or prescribed industrial waste. (For complete abstract open document) Analyses of an extensive range of chemical parameters reveals a complex mixture of inorganic and organic compounds, similar to those of international authors researching leachate chemistry. Dominant ions in these leachates are NH4+, Na+, HC03- and Cl-. Except for Fe, heavy metals are not present in significant concentrations (mostly
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ItemOccurrence of nitrate in soil and groundwater in the Corangamite area, Western Victoria( 1996)Soil and groundwater samples taken from two areas of different land use in the Corangamite Region, 200 km west of Melbourne, were analysed for nitrate and ammonium, and in some cases chloride. Both sites are located on the Later Newer Volcanics 'stone rises', and groundwater was sampled from nested bores which intersect the shallow unconfined aquifer and deeper semi-confined aquifer at both sites. The Carpendeit site is an area of native Eucalypt forest, and the Purrumbete North site is a pasture for grazing dairy cows. Low concentrations of nitrate (< 1 mgN/L) in groundwater at Carpendeit correspond to low soil nitrate concentrations (< 3 µgN/cm3 ). Higher groundwater nitrate concentrations occurred in the shallow unconfined aquifer at Purrumbete North, (up to 3 mgN/L), but not in the lower semi-confined aquifer, and corresponds to higher nitrate concentrations in soil (1 to 60 µgN/cm3 ). Elevated nitrate concentrations also occurred in groundwater discharge at McVeans Springs, in the range 2.61 to 4.72 mgN/L, and at Ettrick Springs in the range 8.08 to 16.07 mgN/L, greater than the limit of 10 mgN/L for drinking water specified in ANZECC water quality guidelines. Nitrate in soil under the pasture is probably derived primarily from the activity of nitrogen fixing bacteria associated with subterranean clover introduced to the pasture. Soil nitrate distributions suggest intense return of nitrogen in dung and urea occurs at 'camps' locations on the pasture, where cows tend to gather for shelter. Transport of nitrogen to shallow groundwater is stimulated by cracks and channels in the basalt clay soils. Local groundwater flow includes interaction with the many lakes and temporary ponds 'which form in surface depressions at times of high rainfall. The ponds probably serve as an effective nitrate supply in recharge to the shallow aquifer.
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ItemStructural geology of the area between Bacchus Marsh and Blackwood( 1968)Scope of study: This thesis is concerned primarily with the structural geology of the Ordovician basement rocks along the Lerderderg River Gorge and its two main tributaries. Deformation of the Ordovician rocks constituted the fundamental interest that led to the detailed study of structural elements at various scales. Fabric diagrams were widely used in structural of macroscopic structures. Micro-fabric analysis was not applicable because of low grade regional metamorphism and the fine texture of the rocks. A computer programme used in the preparation of the various fabric diagrams greatly increased the efficiency and accuracy of the study of the structural geometry and symmetry of the deformed Ordovician rocks. A brief description is given of the Permian glacial deposits, the Cainozoic alluvial deposits, the Older and Newer Basalts, the quartz veins, and the different types of dykes.
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ItemThe geology and hydrogeology of the Corangamite region( 1971)Tectonic activity after the early Cretaceous resulted in a complete change in the depositional environment in the sedimentary basin - the Otway Basin - located to the south of the Western Highlands of Victoria and to the west of Melbourne. ThiS Basin became subject to increasing marine influences and the sediments deposited include thick sequences of Miocene marls: the Gellibrand Marl. The water in the marls and in the underlying sands of the Dilwyn Formation is saline near Lake Corangamite but elsewhere water of good quality is found in the sand aquifers, indicating that tectonic activity has caused the local isolation of the lower formation from the effects of flushing by fresher groundwater. Continued tectonic activity and associated volcanic activity during the Miocene and Lower Pliocene resulted firstly in the regression of the sea then the development of the internal drainage characteristic of the Corangamite Region. The sea probably retreated to the southeast as indicated by the unusual parallel physiographic features which have influenced the flows of 'earlier' Newer Volcanic lavas in the Curdie River area and the subsequent development of this river's drainage system. These features are probably related to remanent coast strandlines. The quality of the groundwater found in the 'earlier' lavas is generally poor but the basalts and tuffs of the 'later' Newer Volcanic age often contain water of low salinity, particularly in the intake areas which are located in the ‘stony rises' or near the volcanic cones. The intake area water of the Mt. Warrion basalts is a low salinity calcium-magnesium-bicarbonate water, having an unusually high nitrate content. As the salinity of the water increases away from the intake area the chemical nature of the water approaches that of a dilute sea water. This has been interpreted as being the result of a release of 'oceanic' connate salts by weathering of the calcareous material found in the tuffs and scoria beds of the volcanic cones. The material has been derived from the underlying marl sequence and has been incorporated into the igneous rocks during eruption. The high nitrate concentration has been attributed to the effects of pollution, since there is some evidence that the nitrate values have increased over the last sixty years, but there is also probably an increased rate of fixation in the intake area due to the effects of cultivation. The high bicarbonate values are probably due to a high rate of absorption of carbon dioxide from the atmosphere in the intake areas. The hydraulic characteristic of the basalts ensures the rapid distribution at the high nitrate and bicarbonate waters of the intake area over large areas, hence the effects of pollution are more readily noticeable. The groundwater regime plays an important role in the transfer of dissolved salts in the mainly saline water domain of the Corangamite Region. The study of the water and salt content of some of the lakes of the area indicates that a balance exists that results in the maintenance of a specific lake salinity within narrow limits, and in which the groundwater regime is often involved. By considering the salt balance and water balance of a system as one parameter, referred to as the Hydro Salinity Factor, a simple mathematical model can be postulated to determine some of the unknown factors involved in the maintenance of an equilibrium salinity in a lake. The drilling programme and groundwater investigation outlined an important water resource located in the Warrion area. Already 40 bores have been drilled in this area and they produce 6.6 x 105m3 /year (800 acre feet/year). There is an annual underflow of about 1.5 x 107 m3 (12,000 acre feet). This quantity is well within the 'safe yield' of the area and further development should be encouraged, but because of the presence of the large number of saline lakes in the area, saline water intrusion into the basalts would rapidly occur if the groundwater levels are lowered beneath the lake levels.