Thesis (M.S.)--University of California, Santa Cruz, 1993. / Typescript. Includes bibliographical references (leaves 193-197).

Thesis (M.S.)--Brigham Young University. Dept. of Geology, 2005. / Includes Bibliographical Information (leaves 22-24).

Thesis (M.Eng.)--Memorial University of Newfoundland, 2003. / Bibliography: leaves 71-74. Also available online.

Thesis (M.S.)--University of Nevada, Reno, 2006. / "December, 2006." Includes bibliographical references. Online version available on the World Wide Web.

Magister Scientiae - MSc / Deformation of the western part of the Table Mountain Group rocks during the Cape Orogeny created a series of folds and associated fractures. The subsequent continental break-up of Gondwana led to the development of large fault systems. These exert a major influence on deep and shallow groundwater flow. There are 3 main types of structures that are investigated. The geological contacts between hydraulically different lithologies, the primary characteristics of the sediments comprising the main geological units and the secondary structures developed from the tectonic events. These inter-alia include lithological boundaries, bedding and conjugate joints and large faults. Compartmentalisation of the aquifers by lithological and fault boundaries are the main regional level controls on flow in the study area. Joints are important for local control of flow, but cumulatively exert a regional effect as well. These controls exert a strong 3 dimensional impact on flow patterns within the area. Geological cross sections and detailed fieldwork combined with the conceptual models proposed are used to determine groundwater flow and the extent of the flow constraints. There is heterogeneity in the fault characteristics whilst there isconsistence in the impermeable aquitards. These effect boundaries at the base of the aquifer, divide the aquifer into upper and lower units and cap the top of the aquifer. Using water level data, EC and pH an attempt is made to establish patterns created by structures, mainly faults. There appears to be some control of these shown by patterns seen on contour plots of the data. Understanding of the structures can significantly alter the way the available data could be interpreted. The integration of all available data into the conceptual model provides an effective research tool, which opens up further avenues for new approaches and methods for continued research in this area. / South Africa

Philosophiae Doctor - PhD / The focus of this study was on recharge mechanisms and recharge estimation within the Table Mountain Group area. The study evaluated recharge processes and recharge estimation methods in the Table Mountain Group aquifer systems. / South Africa

Magister Scientiae - MSc / The Western Klein Karoo-Montagu area is located in the mid-eastern of the Western Cape Province , South Africa. In most of the study areas within semi-arid climatic zone , groundwater plays an important role in meeting both agricultural and urban water requirements. Developments of agriculture depend on more and more groundwater supply from Table Mountain Group (TMG) sandstone aquifer system in the study area. Groundwater recharge is considered as one of the most important factors governing the sustainable yield of groundw ater exploitation. There have been few studies on the recharge estimation of the TMG aquifer system in the Montagu area. Thus accurate and reliable recharge estimation of the TMG aquifer system in the Montagu area is important. The TMG aquifer in the Montagu area comprises approximate 4,000m thick sequence of sandstone with an outcrop area of 3,124 km2, which is recharge area. The outcrops are characterized by mountainous topography with sparse to dense vegetation, shallow and intermittent diverse soils and mean annual rainfall of 350-450 mm/yr. Based on detail analysis and interpretation of factors influencing recharge, water balance method is used to estimate recharge rates by using readily available data (rainfall, runoff, temperatures). Other estimate methods are difficult to be applied due to the limited information available in the study area. In this study, the water balance approach based on empirical evapotranspiration and runoff model is employed to determine and analyse long-term average water recharge. The long-term average recharge is modelled as a function of the regional interaction of the site conditions: climate, soil, geology and topography. Modelling is performed according to the outlined procedure using long-term climatic and physical data from the different rainfall period of different gauge stations. As results, actual evapotranspiration, direct runoff and recharge have been quantified. The recharge ranges vary from 0.1 mm/yr to 38.0 mm/yr in the study area, and the values less than 20.0 mm/yr are predominant. Relatively low recharge rates coincide with low precipitation in most regions. Recharge is less than 5.0 mm/yr if mean annual precipitation (MAP) is less than 400 mm/yr. The ranges of 10.0-20.0 mm/yr of recharge occur in precipitation ranging from 600 mm/yr to 1,200 mm/yr. The recharge rates exceeding 20.0 mm/yr are more related to the precipitation with 800 mm/yr or more. The low recharge rates less than 2.0 mm/yr are related to single high rainfall event in the study area. The total recharge volume of the outcrop of the TMG in the study area is approximately 54.2× 106m3/yr . Approximately 29.3% of the stream flow may be contributed by recharge in terms of baseflow. The recharge in the study area increases with increasing precipitation, but recharge percentage is non-linear relationship with the precipitation. Separate high rainfall events mainly contribute recharge if annual precipitation is extremely low in the study area. Spatial distribution of recharge is associated with the variations in precipitation, geological and geomorphologic settings in the study area. The method used yields a point estimate and then ext rapolate s to the whole study area. The ranges of recharge may be exaggerated or underestimated due to the finite number of the rainfall stations in the outcrop of the TMG of the study area. After comparison to other recharge estimates from early studies in the area, the estimates are considered as reasonable and reliable. The feasibility of the water balance approach in semi-arid area is confirmed as well. The estimates based on the water balance model should be crosschecked before they are applied for management of groundwater resources. / South Africa

Groundwater is an important natural resource and ought to be protected. Groundwater recharge and contamination are two important aspects in groundwater management. Both these aspects apply to the vadose zone. The research aimed to narrow the knowledge gap between practising geohydrologists and engineering geologists, both frequently involved in vadose zone investigations for geohydrological and engineering purposes respectively. The vadose zone is the portion of the geological profile above the groundwater surface and is usually characterised by unsaturated conditions. Matrix forces counteract the force of gravitation to hold liquid in the porous medium and are reflected by hydraulic heads lower than atmospheric pressure (suction). The unique relationship between soil-water content and suction is presented by soil-water characteristic curves. Flow of liquids is directly proportional to the hydraulic gradient and the hydraulic conductivity and is affected by the geometric properties of the pore channels. In unsaturated soils, flow is governed by both matrix and gravitational forces. Preferential flow is the process by which water and solutes move along preferred pathways through a porous medium. Important hydrogeological properties, such as porosity, hydraulic conductivity and soil-water retention characteristics, can be estimated from geotechnical data. Unsaturated hydraulic conductivity can also be estimated from soil-water characteristic curves and saturated hydraulic conductivity. The experimental procedures comprised analyses of existing hydrogeological data, laboratory tests and field experiments. The geotechnical data were used to predict important hydrogeological properties and these predictions were compared to experimentally derived hydrogeological properties. The effects of preferential flow and soil variability were also investigated. Predictions of porosity, hydraulic conductivity and soil-water retention characteristics lack precision, owing mostly to the natural variability in hydrogeological properties and inherent errors of the empirical models. Accurate predictions of unsaturated hydraulic conductivity were based on experimentally derived saturated hydraulic conductivity and soil water characteristic data. The study area is located in Midrand and is underlain by granitoid rocks that had been subjected to a number of geomorphologic events. The land system classification approach was used to delineate the hydrogeological units. The different hydrogeological characteristics can be attributed mainly to the position of the hydrogeological units in respect of the topographical setting, the geomorphologic history and the underlying geology. A conceptual hydrogeological model was constructed for each of the hydrogeological zones and its significance in respect of groundwater recharge and vulnerability discussed. The research has shown that geohydrological properties can be estimated from geotechnical data with various degrees of accuracy. Predictions of hydraulic conductivity, soil water retention characteristics and porosity are not suitable for site-specific investigations, but it can be used during the feasibility phases. In cases where saturated hydraulic conductivity and soil-water retention characteristics have been experimentally derived, estimations of unsaturated hydraulic conductivity are adequate for site-specific investigations. The land system approach can be used to delineate areas of similar geohydrological characteristics and these can be used in the compilation of aquifer vulnerability and groundwater recharge maps. / Thesis (PhD)--University of Pretoria, 2006. / Geology / Unrestricted

The Swartkops River and Sundays River Estuaries are different in terms of morphology and the level of human impact. Budget models of DIP and DIN were constructed for each estuary at different riverine flow rates, using the Land-Ocean Interactions in the Coastal Zone (LOICZ) protocol. Nutrient dynamics in the estuaries were investigated using nutrient data and the results of the models. The Swartkops River Estuary acted as a sink of DIP and DIN, while being net heterotrophic. The Sundays River Estuary acted as a source of DIP and DIN, while being net autotrophic. Both systems were net denitrifying. The Swartkops River Estuary shows greater anthropogenic impacts in terms of nutrient loads than the Sundays River Estuary. A shift in nutrient concentration trends and system properties occurred between conditions of low and high riverine flow rates. The Swartkops River and Sundays River Estuaries were shown to be ‘outwellers’ of DIN and DIP, while having an important influence on the ratio of DIN:DIP exported to the adjacent ocean. Comparisons with other estuaries suggested that riverine flow into estuaries in the Eastern Cape region may display natural DIN:DIP ratios which are lower than the global average for “pristine” systems. Such ratios would be decreased further by increased water extraction for human activities.

This study reports the results of an investigation of the potential pollution hazard of a potash brine disposal pond located near Esterhazy, Saskatchewan. The most serious problems associated with the brine pond are the potential pollution of groundwater resources and the possible contamination of a nearby stream by groundwater discharge. The primary geologic feature is a glacial buried valley aquifer consisting of highly-permeable sands and gravels. A three dimensional electric analog model was constructed to simulate the steady state and transient groundwater flow systems in the buried valley aquifer. The steady state analysis enabled the author to calculate the convective travel times of the brine from the brine pond to the nearby creek. The transient analysis was used to assess the feasibility of reversing the hydraulic gradient in the buried valley aquifer. Steady state results indicate that the most serious potential pollution hazard is brine seepage onto the surface immediately east of the brine pond. At a distance of 5600 feet from the brine pond, this seepage will occur within 30 years; nearer to the brine pond, it will occur sooner. This type of brine seepage could enter the nearby stream as a result of surface drainage. Brine pollution by groundwater discharge directly into the creek will take between 640 to 1260 years, so this mechanism does not pose an immediate pollution hazard. Transient results indicate that low-rate injection wells (up to 50 IGPM) would not reverse the hydraulic gradient in the buried valley aquifer. Injection rates between 370 to 575 IGPM would be required, but fresh water supplies of this magnitude are not available. The design of future brine ponds should include seepage calculations in the initial phases of design instead of after the fact. / Science, Faculty of / Earth, Ocean and Atmospheric Sciences, Department of / Graduate