• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 328
  • 62
  • 49
  • 34
  • 21
  • 8
  • 5
  • 3
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • Tagged with
  • 598
  • 217
  • 122
  • 92
  • 89
  • 64
  • 62
  • 60
  • 59
  • 56
  • 43
  • 41
  • 40
  • 40
  • 32
  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
11

Hydrogeology of the Catalina area, near Tucson, Arizona

Onyskow, Lawrence Paul, January 1989 (has links) (PDF)
Thesis (M.S. - Hydrology and Water Resources)--University of Arizona, 1989. / Includes bibliographical references (leaf 120).
12

Geologic controls on the occurrence and movement of water in the Lower Cienega Creek Basin

Ellett, William Jess, January 1994 (has links) (PDF)
Thesis (M.S. - Hydrology and Water Resources)--University of Arizona. / Includes bibliographical references (leaves 113-116).
13

Hydrogeology of the Mackenzie Basin : a thesis submitted in partial fulfilment of the requirements for the degree of Master of Science in Engineering Geology in the University of Canterbury /

Cooksey, Kirsty. January 1900 (has links)
Thesis (M. Sc.)--University of Canterbury, 2008. / Typescript (photocopy). "August 2008." One col. map in pocket of v. 1. Includes bibliographical references (leaves 174-181, v. 1). Also available via the World Wide Web.
14

The genesis and hydrogeology of a sandstone karst in Pine County, Minnesota

Shade, Beverley Lynn. January 2002 (has links)
Thesis (M.S.)--University of Minnesota, 2002. / Description based on print record. Includes bibliographical references. Also issued in typescript.
15

Hydrogeochemical characterization of springs and wells in the Cacapon Mountain Aquifer

Corder, Lacoa L. January 2008 (has links)
Thesis (M.S.)--West Virginia University, 2008. / Title from document title page. Document formatted into pages; contains vii, 80 p. : ill., col. maps. Includes abstract. Includes bibliographical references (p. 62-64).
16

Hydraulic properties of the Table Mountain group (TMG) aquifers/

Lin, Lixiang. Unknown Date (has links) (PDF)
Thesis (Ph. D) -- University of the Western Cape, 2007. / includes bibliographic references (leaves 117-126).
17

Hydrology and geomorphic evolution of basaltic landscapes, High Cascades, Oregon /

Jefferson, Anne January 1900 (has links)
Thesis (Ph. D.)--Oregon State University, 2007. / Printout. Includes bibliographical references (leaves 162-175). Also available on the World Wide Web.
18

Hydrogeochemical assessment of the Mooiplaas dolomite quarry near Laudium in Gauteng, South Africa

Van Staden, Christel January 2020 (has links)
Karst aquifers within dolomite terrain in South Africa have been researched in the past for dewatering due to gold mining, sinkhole formation, and for its high value to supply sustainable, good quality groundwater. Karst aquifers are also known to be extremely vulnerable therefore, they should be protected and taken care of. Thus, understanding how anthropogenic activity influences the hydrogeochemistry of a karst aquifer is extremely important. Pretoria Portland Cement Mooiplaas (PPC Mooiplaas) quarry was chosen as the study area because the mining of dolomite, below the natural groundwater level, is a great example of anthropogenic activity within a karst aquifer. There are several factors that influence the movement of the groundwater within the study area such as dykes, faulting and the anthropogenic activity of mining activity itself; such as the plant and the Slimes Dams that produce the product. The main objectives of the study were to characterise the hydrogeochemistry of the PPC Mooiplaas and to compare the water quality of PPC Mooiplaas to that of it surrounding karst aquifer. To identify the movement of water within the study area by stable isotope analysis and to identify the source of water within the study area. Then lastly it is to understand how the anthropogenic activity impacts the karst aquifer This was carried out by sampling several sites of groundwater (West Pit Seep, Exploration Borehole North, Exploration Borehole South, West Pit Wall Seep, East Pit Wall Seep, Groundwater Flow 1 and Groundwater Flow 12); surface water (West Pit, East Pit and Fish Dam); mine water (Plant Inlet, Slurry Dam, Metallurgical Grade “Vergryser” Slurry Dam and Slimes Dam); and rainwater. The water samples that were collected at PPC Mooiplaas were tested for major inorganic chemistry and stable isotopes. Due to several factors that influence the water, it is possible to use water chemistry and stable isotopes to gain an understanding of the source of groundwater and the movement of water in the study area. It was found that the groundwater and the surface water at PPC Mooiplaas is mainly characterised by Ca2+-Mg2+-HCO3- type of water. The groundwater is mainly freshly recharged groundwater with lower average values of pH than the surface water. When the inorganic chemistry results of PPC Mooiplaas was compared to the surrounding karts aquifer chemistry it was seen that the mine has high amounts of NO3- in it. It was also seen that the Hennops River is contaminated by sewage due to the high concentrations of NH4+ and very small amounts of NO3-. This indicates that the NO3- contamination caused by PPC Mooiplaas has a very small impact on the river but it still has a substantial impact on the groundwater downgradient of the mine. The hydrogeochemical at PPC Mooiplaas is consistent with the understanding of what groundwater in a karst environment is. The study also showed that mining dolomite at PPC Mooiplaas does not have detrimental environmental effects besides elevated NO3-. In addition to assessing the hydrogeochemistry of the water samples collected at PPC Mooiplaas stable isotopes were used to identify the source and possible pathways of the water in the study area. The isotope data indicated that the WPS water is freshly recharged groundwater with the Expl BHs possibly being the source of water seeping at the WPS. The isotope data also showed that the wall leaks, WPWS and EPWS both have a component of SsD since both these sampling locations deviate from the LMWL. The major surface water bodies e.g. the WP, EP and the FD is groundwater with a slight evaporation signature. PPC Mooiplaas is a great example of the effects a dolomite mine has on a karst aquifer with the main impact being an increase in NO3- concentration. High amounts of NO3- can cause serious negative effects to human health if consumed therefore, it is recommended that the PPC Mooiplaas treats the water for NO3-. PPC Mooiplaas would be ideal to conduct further studies at like such as tracer test along the dykes and faults which will be valuable to understand movement of contamination in a karst aquifer. It is possible that the NO3- contamination is isolated within the compartment since these compartments are known to be barriers. It is recommended that NO3- is used as a tracer to investigate if water and its contaminants move across these boundaries. A hydrocensus was not included in this study. It is recommended the a thorough hydrocensus is conducted with the main objective to obtain groundwater level data in the surrounding area. This will enable a better understanding of the groundwater flow direction in the study area. / Dissertation (MSc (Hydrogeology))--University of Pretoria, 2020. / Geology / MSc (Hydrogeology) / Unrestricted
19

Hydrogeochemistry of the groundwater in the Namaqualand region, South Africa : implications for surficial uranium mineralization

Makubalo, Sisanda Sesethu January 2020 (has links)
Since the discovery of the Yeelirrie deposit in Australia in 1972, exploration for surficial uranium deposits has been supported through hydrogeochemical studies of groundwater and the calculation of the carnotite solubility index (CSI). This study aims to evaluate groundwater quality and delineate potential areas where surficial uranium mineralization (i.e. carnotite) may take place in the Namaqualand region. Surficial uranium deposits are unconsolidated soils or sediments, usually of Tertiary to Recent age. The most common surficial uranium mineral is carnotite. The study area in Namaqualand is located in the arid to semi-arid Northern Cape Province of South Africa, which comprises a variety of metamorphic rocks of the Namaqua Metamorphic Province, overlain by Cenozoic sediments. A total of 85 water samples were collected from existing boreholes. Physicochemical properties (EC, TDS, pH, DO and Eh) were measured on site and samples were analysed for major ions and trace elements at the Council for Geoscience laboratory in Pretoria. The CSI was calculated using hydrochemical data, and interpolated using inverse distance weighting (IDW) and kriging to produce maps of potential carnotite mineralization. The groundwater of the area is alkaline, with elevated concentrations of EC, TDS, Na+, Cl-, F-and U. The predominant water types are Na-Cl, Na-HCO3 and Mg-HCO3. Most groundwater samples have uranium values that range from 1.2–5 120 ppb, which are above the World Health Organization drinking water quality guideline of 15 ppb. Analysis shows that, in the presence of carbonates, uranium mostly occurs in solution as UO2(CO3)22- and UO2(CO3)34-. The CSI values ranged from -6.71 to -2.99 and those that ranged from 2.99 to -4 were in close proximity to known surficial uranium occurrences. The use of IDW and kriging interpolation methods revealed areas with potential for carnotite mineralization. The existence of suitable uranium source rocks, palaeochannels, climate and geomorphology makes the Namaqualand region prospective for calcrete-hosted uranium deposits. The CSI, used to delineate areas with a potential for surficial uranium mineralization in the Northern Cape, can be extrapolated to other areas with similar geological environments and climatic conditions. More sampling of groundwater is recommended to conduct a medical geology study to ascertain the impacts of uranium and other elements on the people, animals and plants of the area. / Dissertation (MSc)--University of Pretoria, 2020. / Council for Geoscience / Geology / MSc / Unrestricted
20

Water Supply Potential of the Wilcox Aquifers in Lafayette County, Mississippi

Banks, John Vernon 15 August 2014 (has links)
The Meridian-upper Wilcox aquifer in Lafayette County, Mississippi, is the primary source of water for the public and industrial supply in the county. A comprehensive study of the subsurface hydrogeology of the county was undertaken to predict if the aquifer had the potential to supply sufficient water to prospective industry in Lafayette County. After completing a series of cross sections, the aquifer dimensions were better characterized. Potentiometric mapping provided necessary water level information, and these data were input into analytical models used to project drawdown from pumping in the aquifer. Results suggest the Meridian-upper Wilcox aquifer in western Lafayette County would support an increased groundwater demand of 50% for a thirty year period for a new industrial complex.

Page generated in 0.0527 seconds