MSc., Faculty of Science, University of the Witwatersrand, 2011 / ABSTRACT This study was an investigation of the impact of recharge water with respect to quality and quantity into the Rehabilitated Block I opencast operation, a former opencast coal mine in Mpumalanga, Witbank Coalfields western complex. The rehabilitated areas consisted of three mined mini-pit areas known as Block I, Block I Extension A and B. The area has been rehabilitated by backfilling and leveling of spoil material, subsoil material, placement of approximately 400-mm topsoil layer and grassing. As part of the vegetation maintenance lime is added per annum, in an effort to neutralize the soil cover and further assist in neutralizing the potential acid mine drainage. Additional monitoring boreholes were drilled to increase the monitoring of the water quantity and qualities. Ground and surface water samples were taken, analysed for pH, conductivity, redox potential, sulphates, carbonates and trace metals. The pH of the ground and surface water ranged from moderately acidic to alkaline. One of the monitoring boreholes located on the lowest elevation of the Block I area was observed to be filled up to the collar level of the borehole with water samples showing elevated Fe and Mn concentrations of 216 and 46.2 mg l-1 respectively. The water classification revealed the following facies: Ca-Mg sulphate type for the borehole water and Ca-Mg sulphate-bicarbonate type for the surface waters. Acid base accounting studies on the soil samples showed a negative net neutralising potential of up to -9.8 kg t-1 CaCO3 which indicated the potential of acid mine drainage in the area. The total metal analyses showed that the area was contaminated with heavy metals such as Fe, Cr, Mn, Ni and Zn and the metalloid As was also detected. The highest recorded concentrations of total metals were 78 252; 2 402; 1 959; 1 360 and 15 109 mg kg-1 respectively. The highest concentration of Arsenic was detected at 824 mg kg-1 respectively. The transmissivity of the boreholes in the spoil material was highly variable and ranges from 100 to 5 000 m2 day-1. Pump testing suggests that borehole yields of between 23 and 4 l s-1 can be expected in the spoil areas. The specific yield or the drainage porosity of the spoil material was in the range of 25 to 30 %.

Graduation date: 1995

Thesis (M.S.)--University of Montana, 2006. / Title from title screen. Description based on contents viewed Mar. 23, 2007. Includes bibliographical references (p. 94-96).

Thesis (M.S.)--Baylor University, 2005. / Includes bibliographical references (p. 48-50).

Thesis (Ph. D.)--Lehigh University, 2000. / Includes vita. Includes bibliographical references (leaves 220-229).

Thesis (M.S.)--Oregon State University, 2002. / Typescript (photocopy). Includes bibliographical references. Also available on the World Wide Web.

Atmospheric noble gases (He, Ne, Ar, Kr, and Xe) dissolved in groundwater are a valuable tool in hydrology. Numerous studies have relied on groundwater recharge temperatures calculated from dissolved noble gas data (noble gas temperatures, NGT) to infer paleoclimate conditions. This research investigated gas dissolution during groundwater recharge and critically examined the use of dissolved noble gas data in groundwater research. A detailed investigation of an agriculturally impacted shallow aquifer allowed comparison of measured water table temperatures (WTT) with calculated NGT. Results suggest that NGT calculated from widely used noble gas interpretive models do reflect measured WTT, supporting the use of dissolved noble gases to deduce recharge temperatures. Samples having dissolved gas concentrations below the equilibrium concentration with respect to atmospheric pressure were attributed to denitrification induced gas stripping in the saturated zone. Modeling indicated that minor degassing (<10% [Delta]Ne) may cause underestimation of groundwater recharge temperature by up to 2 °C. In another study a large dissolved noble gas data set (905 samples) from California was analyzed. Noble gas modeling using the same interpretive models indicates that multiple models may fit measured data within measurement uncertainty, suggesting that goodness-of-fit is not a robust indicator of model appropriateness. A unique aspect of this study was the high Ne and excess air concentrations associated with surficial artificial recharge facilities. A final study examined whether climatic/hydrologic changes occurring over glacial-interglacial time periods could impact the accuracy of NGT used in paleoclimate studies. Numerical modeling experiments estimated WTT sensitivity to changes in: 1) precipitation amount, 2) water table depth, and 3) air temperature. Precipitation and water table depth had a minor impact on WTT (~0.2 °C). In contrast, the impact of air temperature changes on WTT was more pronounced. Results suggest that air temperatures inferred from NGT data may underestimate actual air temperature change since the last glacial maximum by ~1 °C at sites having seasonal snowcover. These results suggest despite uncertainty in the exact physical processes controlling gas dissolution during groundwater recharge, NGT do reflect WTT. However, inferring paleo-air temperatures from NGT are subject to error, especially locations with seasonal snowcover. / text

Not available / text

Understanding the spatial and temporal dynamics of catchment systems is crucial to understanding how hydrological behaviour may change over time and how this impacts on crucial aspects of catchment management such as flood generation, water resource management and the sources and fluxes of sediment, nutrients and contaminants. A combined statistical analysis was undertaken to assess whether similar catchment groupings respond to changing climatic drivers in the same way. A k-means cluster and PCA analysis grouped catchments in four clusters, which were differentiated by their topographical differences between lowland and upland catchments. Lowland catchments exhibited similar behaviours to changing trends of key hydroclimatic variables whereas more upland catchments showed diverse responses. We assessed the behaviour of 8 mesoscale catchments with increasing lowland areas for spatial and temporal runoff dynamics via the application of environmental tracers (stable isotopes and Gran alkalinity). Mean transit times were estimated using a lumped convolution integral model and lowland catchments with greater coverage of sedimentary bedrock exhibited longer turnover for water and solute fluxes. Tracer data was then implemented into a conceptual rainfall-runoff model to develop a model, which could represent both spatial and temporal dynamics rather than simply recreating the observed stream hydrograph. Finally, we assessed the role of dominant landscape characteristics (urban environments and grazing pastures) on the sources and fluxes of microbial contaminant risk to water quality. Catchments which had larger urban coverage and higher portion of grazing pastures yielded higher concentration fluxes of faecal coliforms which provided a first-order approximation of water quality risk at the catchment scale.

Research Project Technical Completion Report, Project No. G828-24, Prepared for the U.S. Department of the Interior, September 1984. / / With the growing problem of ground water contamination by volatile organic substances, drinking water sampling programs are being initiated throughout the United States. A need was recognized for a manual on well water sampling that would bridge the gap between highly technical documents and over -simplified reviews. A primer was therefore developed on establishing and implementing a sampling program. Current information was collected by means of both library research and extensive contact with public agency employees and practicing hydrologists. Portions of a sampling program that required explanation included selection of priority wells, proper sampling at the well head, sample preservation and shipment, chain of custody procedures, laboratory selection, quality assurance and data evaluation. Explanation of these steps is intended to help ensure the legal defensibility of any collected data.