Thesis (Ph. D.)--Institute of Paper Chemistry, 1958. / Includes bibliographical references (p. 189-192).

Thesis (Ph. D.)--University of Texas at Austin, 2001. / Vita. Includes bibliographical references (leaves 255-268). Available also in a digital version from Dissertation Abstracts.

Thesis--M. Phil., University of Hong Kong, 1983.

Thesis (M.S.)--University of Wisconsin--Stevens Point, 2002. / Includes bibliographical references (leaves 69-75).

The dry valley systems in the Kalahari of southern Africa are traditionally considered to have developed as a result of past fluvial activity. However, it has also been suggested that erosion by groundwater processes (sapping and deep-weathering) had an important role in development. This thesis aims to establish the relative role of each of these process areas in mekgacha evolution using a combined geological and geomorphological approach. The study area is restricted to the valley systems of Botswana, eastern Namibia and the Northern Cape Province of South Africa, which can be subdivided into exorcic and endoreic systems directed towards the Orange River and the continental interior, respectively. Field studies, analyses of remotely-sensed imagery and a consideration of network orientation identify evidence for the role of both fluvial and groundwater processes in valley development. However, whilst both groups of processes have operated, the importance of each is suggested to have varied both spatially and temporally. Fluvial processes are indicated by sequences of sediments, relict channels and terrace levels, and appear to have operated most recently. Sapping processes are implied in the formation of certain valley systems, primarily from morphological properties and the presence of relict spring lines. Deep-weathering processes are implicated from the close parallelism of many valleys with geological structures now buried beneath thicknesses of Kalahari Group sediments. Borehole records also indicate deep-weathering of bedrock beneath valleys developed above fracture zones, which is suggested to have operated over the longest timescales. Thin-section studies of duricrusts from valley flanks, together with duricrust profiles and records from lithological boreholes, indicate the role of groundwater in their formation. Results suggest an intrinsic link between duricrust formation and valley development. Geochemical and thin-section analyses of duricrusts further suggest that previous considerations of the palaeoenvironmental significance of Kalahari silcretes based upon TiO2 levels may not be wholly appropriate.

Groundwater is critical in Texas, representing 60 percent of total water used in 2008. Water demands in Texas are projected to increase 22 percent, largely from an almost doubling of population, within the next 50 years; this ever-increasing pressure on Texas water supplies underscores the need to optimize management of water resources. The objective of this study was to assess regulations, scientific information, and rulemaking by groundwater conservation districts (GCDs) that support policies that achieve the legislative intent of GCDs to protect and conserve groundwater resources of the states aquifers. This study's scope was the Carrizo-Wilcox Aquifer and managing GCDs and the following key topics were evaluated 1) management and protection issues; 2) if and how GCDs are utilizing science in development of management plans and rules; 3) whether GCDs are implementing management plans and using enforcement actions; 4) determining if GCDs would have production budgets in conflict with the Regional and State Water Plan and use of the aquifer; 5) and comparing the management plans of GCDs for compatibility. Two online surveys were developed to solicit responses from GCDs and interested parties. Results show that the predominant management issues stemmed from the uncertainty in how groundwater production was regulated and how future permitting would proceed. Environmental interest groups were concerned that GCDs would not adequately incorporate science that supports groundwater production budgets. Stakeholder groups perceived groundwater conservation management as adversely impacting their individual property rights and their region’s ability to develop water management strategies that address projected water budgets. Few formal enforcement actions have been taken by GCDs since 2007. Current water budgets and desired future conditions by the GCDs for the Carrizo-Wilcox Aquifer do not conflict or result in long-term deficits with respect to water budget projections established by the 2011 Regional Water Plans. GCDs adopted groundwater management plans that addressed goals including conservation and recharge, as outlined in the Texas Water Code, by creating varied objectives and standards. Unanimous public acceptance of the management plans and rules established by the GCDs may never be accomplished, but acceptance will improve through the continuation of public communication, stakeholder coordination, and education. / text

Just as children eventually learn that covering their eyes does not make them invisible, we as adults have realized that just because harmful substances are "out-of-site" it does not necessarily mean they are gone for good. As we expanded our ability to think abstractly we began to consider how our actions affect our future and the lives of future generations. For example, we established procedures for the handling and disposal of high level radioactive waste and other hazardous materials because of the threat such materials pose to the environment. To date, however, the effect of atmospheric pollutants on groundwater supplies has been virtually ignored. Atmospheric pollution sources include, but are not limited to, smoke stack emissions, releases from power plants, weapons testing and manufacturing, fires, explosions, and deflation from tailings, spills and playas. This study evaluates the potential for groundwater to be contaminated by a point-source atmospheric emission. Pollutant concentrations in groundwater are estimated using a Gaussian model of atmospheric transport, a transfer function model for transport through the unsaturated zone, and a two-dimensional groundwater flow model based on Darcy's law to simulate transport in the saturated groundwater system. A sensitivity analysis of the composite atmospheric-groundwater transport model suggests that the most important factors influencing the susceptibility of a groundwater system to contamination by an aerosol source are: the concentration of the source, the amount of recharge, the depth to the water-table, and the velocity distribution in the unsaturated zone. This study indicates a significant potential for pollution of groundwater systems by aerosols. Shallow aquifers are especially vulnerable; however, deeper aquifers where rapid travel times through the unsaturated zone exist are also susceptible to aerosol contamination. / text

Previous studies have shown that municipal water can provide a substantial surface water and groundwater recharge source for the Edwards aquifer in central Texas. Knowledge of how water sources to urban watersheds change with urbanization is essential for sustainable water resource management. The range for 87Sr/86Sr values for Austin municipal water (0.7086–0.7094) is distinct from that of naturally occurring phreatic groundwater (0.7076-0.7079) and stream discharge in many rural watersheds (0.7077– 0.7084). Many streams in urbanized Austin watersheds have elevated 87Sr/86Sr values (0.7085–0.7088) relative to these rural streams. These differences demonstrate the potential for Sr isotopes to serve as a tracer of municipal water inputs to urban streamflow. A few urban streams and springs, however, have 87Sr/86Sr values higher than those of municipal water. Soil is the likely source of these elevated values. Spatial variability in the distribution of high 87Sr/86Sr soil and temporal variability in soil-exchangeable Sr contributions to groundwater may result in naturally high streamflow 87Sr/86Sr values, making the identification and quantification of municipal water as a streamflow source using Sr isotopes unreliable in some instances. Temporal variability in climatic conditions and resulting changes in effective moisture can result in distinct natural groundwater 87Sr/86Sr and Mg/Ca ratio variations, due to differences in overall groundwater residence times and water-rock interaction. Unlike natural water sources, municipal water inputs to urban watersheds peak during the summer (and periods of drought) when natural recharge inputs (precipitation) are minimal or nonexistent. Thus, proportions of natural vs. municipal water sources in the streamflow of some highly urbanized streams vary seasonally, resulting in distinct 87Sr/86Sr and Mg/Ca temporal trends, based on the recharge source. In some urban watersheds, municipal water appears to be a significant streamflow component during dry periods. However, temporal variation in natural Sr inputs to vadose and phreatic groundwater may result in the overestimation of municipal water contributions to streamflow and groundwater recharge during relatively wet periods. / text

This report explores the application of a market framework to allocating water resources, with a specific focus on groundwater resources in Texas. Water markets have been touted by economists as an efficient and effective means of reallocating a scarce natural resource and have been implemented in various forms across the western United States. This report discusses the characteristics of water markets that allow them to efficiently allocate water resources as well as the need for institutional oversight to address negative externalities, including environmental and third party impacts. A description of Texas law and regulation of groundwater resources is also given and analyzed in the context of establishing widespread groundwater markets in the state. Several case studies, both in Texas and in other western states, are also analyzed to determine best practices for the creation of a statewide system of groundwater marketing. The report concludes with several recommendations based on these case study analyses and in light of the current legal and regulatory obstacles to widespread water markets in Texas. / text

Not available / text