Thesis (M.S.)--West Virginia University, 2006. / Title from document title page. Document formatted into pages; contains viii, 64, [1] p. : ill. (some col.), map. Includes abstract. Includes bibliographical references (p. 52-56).

Thesis (Ph.D.)--University of Melbourne, School of Earth Sciences, 2010. / Typescript. Includes bibliographical references (p. 319-350)

Thesis (M. Sc.)--University of Canterbury, 2009. / Typescript (photocopy). Includes bibliographical references. Also available via the World Wide Web.

Thesis (Ph.D.)--University of Delaware, 2006. / Principal faculty advisor: John A. Madsen, Dept. of Geological Studies. Includes bibliographical references.

Thesis (M.S.)--Oregon State University, 2006. / Printout. Includes bibliographical references (leaves 166-175). Also available on the World Wide Web.

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Σκοπός της πτυχιακής αυτής εργασίας είναι η προσέγγιση και η μελέτη των υδρογεωλογικών, υδροχημικών και περιβαλλοντικών συνθηκών της υδρολογικής λεκάνης των Τρικάλων. Η περιοχή έρευνας βρίσκεται στη Δ. Θεσσαλία. Γεωλογικά ανήκει στην Πελαγονική Γεωτεκτονική Ζώνη. Έγινε δειγματοληψία επιφανειακών υδάτων για 9 σημεία, καλύπτοντας ένα μεγάλο εύρος της περιοχής μελέτης. Ύστερα από επί τόπου μετρήσεις και αναλύσεις στο εργαστήριο και επεξεργασία τους, προέκυψε ότι τα νερά χαρακτηρίζονται ως κανονικά, γαιοαλκαλικά οξυανθρακικά νερά με βασικό χημικό τύπο Ca-HCO3-. Σε ότι αφορά τις φυσικοχημικές παραμέτρους, οι τιμές της θερμοκρασίας κυμαίνονται από 11 έως 15 οC, και οι τιμές του pH ~8, παρουσιάζοντας ένα βασικό αλκαλικό περιβάλλον, χαρακτηριστικό των επιφανειακών υδάτων. Το σφάλμα ισοζυγίου για το σύνολο των μετρήσεων ήταν εντός των ορίων αξιοπιστίας, παρουσιάζοντας για τα βασικά κατιόντα τις εξής μέσες τιμές: Ca-60mg/l, Mg-18mg/l, Na-6,4 mg/l και K-1,01 mg/l. Για τα ανιόντα, οι αντίστοιχες μέσες τιμές είναι: HCO3 - 243mg/l, SO4- 28,9 mg/l και για το χλώριο 8 mg/l. / --

Northern Oman is an arid area almost entirely dependent upon groundwater recharged by highly sporadic rainfall. Precipitation estimates are hampered by a lack of any reliable altitude-rainfall relationship. Below 700 m there is no statistically significant relationship. The isotopic composition of groundwater is strongly influenced by the rainfall amount (related to storm frequency), and not just by altitude/temperature. Storm events with long return periods are of disproportionate importance to recharge. Despite the huge volume of carbonate formations, holokarstic development is generally immature, and groundwater storage is greatest in alluvial piedmont surrounding main limestone massifs. Isotopes, chemistry and hydrologic measurements show that post-storm evaporative losses are very large. The origin of limestone springs and their chemical and physical anomalies are described. Structure rather than petrology controls groundwater flow in the limestones, hence regional differences in structural style produce contrasting hydrologic regimes between the various massifs. The Semail nappe mantle sequence is the only other hard-rock formation of groundwater significance. Though much less productive than the carbonates, these ultramafics display extraordinary chemical activity, yielding bicarbonate waters from the weathered zone, whilst more deeply circulating groundwaters produce hyperalkaline springs by low-temperature serpentinisation. Associated processes include solute reduction, hydrogen evolution, hydroxide and carbonate precipitation, hydroxide-basic rock reaction, salt enrichment and water-rock isotopic exchange. Throughout the interior catchments, groundwater mostly flows into narrow buried alluvial channels which are often constricted at hard-rock nodal points, thus facilitating very efficient interception and recovery by the "falaj" system. Traditional agriculture has evolved to cope with fluctuating groundwater supply but is sensitive to increased abstraction. On the Batinah plain, greatly increased coastal abstraction has locally induced moderate to severe salinisation. Existing process studies are insufficiently quantified to provide the resolution necessary to manage groundwater resources, especially in high-risk coastal areas.

Master of Science / Department of Geology / Saugata Datta / In specific lithologic and hydrogeological settings, Managed Aquifer Recharge (MAR) projects using vadose zone wells have the potential to outperform infiltration basins in terms of volume of water recharged. Numerical modeling can assist in determining which recharge method is most efficient in infiltrating water to unconfined alluvial aquifers of differing unsaturated zone lithologic complexities. The Sagamore Lens Aquifer (SLA) in Cape Cod, Massachusetts is an example of an aquifer with minimal lithologic complexity while the Hueco Bolson Aquifer (HBA) near El Paso, Texas has greater lithologic complexity. This research combines two U.S. Geological Survey numerical models to simulate recharge from infiltration basins and vadose wells at these two locations. VS2DTI, a vadose zone model, and MODFLOW-2005, a saturated zone model, were run sequentially at both sites and with both vadose well and infiltration basin recharge methods simulated. Results were compared to determine the relative effectiveness of each method at each location and to determine the effects of vadose zone complexity on recharge. At the HBA location, soil samples were tested for conductivity and grain size distribution and a microgravity survey was begun to constrain the models. The infiltration basin structure proved to be more efficient, infiltrating more water volume at both locations. Lithologic complexity formed perched conditions in the HBA model, significantly affecting infiltration rates from both infiltration methods at that location. Methods and conclusion from this study can assist in the modeling and design of future MAR projects, especially in locations with thick or lithologically complex vadose zones.