The intermontane Mackenzie Basin is located within the central South Island of New Zealand. The glacial basin contains three glacial lakes which are used for hydroelectric power generation via a canal system that links the lakes. The basin is an area of climate extremes, low rainfall, high summer temperatures, and snowy winters. The area is predominantly used for pastoral farming, however farming practices are changing and, combined with an increasing population, there is a need to define the groundwater resources to enable sustainable resource management. Little is currently known about the hydrogeological system within the Mackenzie Basin, and what is known is from investigations carried out during the construction of the canal system from 1935 to 1985. There are four glacial formations that overlie Tertiary sequences and Torlesse bedrock. However, due to the glacial processes that have been ongoing over at least the last 300 ka, determining the occurrence and extent of groundwater within the outwash gravels is difficult. It is suggested that the permeability of the formations decreases with depth, therefore horizontal and vertical hydraulic conductivity decrease with depth. A shallow groundwater table is present within the Post Glacial Alluvial Gravels which is recharged directly from fast flowing streams and rivers as well as rainfall. It appears that this shallow system moves rapidly through the system and it is unlikely that the water infiltrates downwards to recharge the deeper groundwater system. It is thought that a deep groundwater system flows preferentially through the Mt John Outwash Gravels, being the second youngest glacial formation. Water chemistry and age dating tracer analysis indicate that the deeper groundwater is over 80 years old and that the groundwater system is recharging slowly. The shallow groundwater in the Post Glacial Alluvial Gravels and within the major fans to the east of the basin is 10 to 20 years in age. Baseline data such as water chemistry, groundwater levels, and surface water gaugings have been collected which can be used for future investigations. More data needs to be collected to create a long term record to further define the hydrogeological system and to determine the best way to manage the resource for long term sustainable use in the future.

An experimental investigation of the behavior of soil water movement under unsaturated transient conditions is reported for the case of vertical infiltration into a sandy loam and silt loam soil material. Water was allowed to enter at a small constant suction into air-dry columns of soil and its subsequent distribution followed with a gamma radiation attenuation device. An analytic expression of water content as a function of depth and time was obtained by multiple regression analysis from which it was possible to determine the instantaneous flux and the water concentration gradient at given water contents. During the early stages of infiltration the relationship between the flux and gradient was linear as prescribed by the Darcy equation. At later times when the gradient became less steep linear proportionality broke down. Non-linearity at low water gradient was evidenced for both soils throughout a wide range of water contents. The magnitude and direction of the departure from linearity was similar for both soils indicating the deviations were possibly not due to specific soil properties, but rather to an inherent characteristic of the flow system itself. An empirical flow equation modeled after the Darcy equation fits the data very well. The behavior of the equation parameters was strongly reminiscent of those of the Darcy equation. Where flux was proportional to the gradient, the equation reduced to the Darcy equation. If flux were not proportional to the water gradient then the term representing the diffusivity of diffusion analysis became a function of both the water gradient and water content.

A chemical-isotopic equilibrium model was developed for adjustment of radiocarbon ages of groundwater from the arid Tucson basin for dilution of the initial groundwater C-14 activity by the solution of soil calcite having a C-14 of 25 ± 19% modern. Input to the model consisted of the laboratory chemical analyses for Ca⁺⁺, Mg⁺⁺, Na⁺, H₄SiO₄, SO₄⁼, HCO₃⁻, CO₃⁼, NO₃⁻, and pH, and δ C-13 for the total dissolved carbon in the groundwater. Output consisted of the equilibrium chemical composition of the groundwater, the ratio of soil CO₂ derived to total dissolved carbon, Q, and δ C-13 of total dissolved carbon, H₂CO₃, HCO₃⁻, and CO₃⁼, and δ C-13 for the soil CO₂ and calcite that initially dissolved in the surface water as it equilibrated with soil minerals. Radiocarbon age of the groundwater is computed from the equation T = 8270 ln [(Q + (1-Q) A(CaCO₃)/Am] where T is the age in years before A.D. 1950, A(CaCO₃) is the soil calcite activity and Am is the measured activity for the dissolved carbonate in the groundwater, both with respect to modern wood. The validity of the model was tested by comparing the predicted values for δ C-13 (CO₂), δ C-13 (CaCO₃) with measured values for samples from the Tucson basin. δ C-13 (CO 2) calculated = (-12.9 ± 1.9) per mil PDB. δ C-13 (CO2) measured = (-15.1 ± 2.8) per mil PDB. δ C-13 (CaCO3) calculated = (-3.9 ± 1.7) per nil PDB. δ C-13 (CaCO3) measured = (-3.6 ± 1.7) per mil PDB. On the basis of these results, the model adequately describes the natural system and may prove useful in future radiocarbon dating work in desert regions.

This study examines the groundwater controversy in U.S.-Mexican relations and the role domestic political structures are likely to play in shaping a bilateral agreement apportioning transboundary groundwater. The study shows that waterpolicy making in the United States takes a distributive form while policy making in Mexico resembles a mobilization style of policy formation. It is argued that these dissimilar national water policy systems affect the way both nations engage the other in bilateral water disputes and are relvant to ascertaining the prospects for resolving the groundwater controversy. The study surveys the relevant hydrological, historical and economic context bearing on the groundwater dispute, then examines the moles of domestic policy making in each country. It follows with an analysis of how national differences in policy making are witnessed in previous bilateral water conflicts. Water policy patterns pertaining to the United States and Mexico respectively strongly influence the making of foreing policy in this sogere. Domestic policy making affects the manner of politization, objectives sought by each nation, and the diplomatic style seen in the adjustment of bilateral water agreements. Patterns seen in previous water conflicts, it is suggested, may obtain in the groundwater case. Nevertheless, the groundwater controversy is substantially different from earlier surface water disputs. Hydrological variation between problem situations is apt to fragment political interests in the United States. Nor is there a firm basis for approaching a settlement in international law. These conditions frustrate extrapolation of past political patterns to the groundwater situation. The study concludes analyzing various methods for resolving the groundwater conflict in light of political limitations. Of these alternatives, a case by case, ad hoc approach to settling the groundwater conflict is indicated as the most feasible approach. Attainment of a fully comprehensive groundwater treaty as now envisioned by the International Boundary and Water Commission (IBWC), is not likely to be achieved. However, formal comprehensiveness can be had by conferring on IBWC comprehensive authority to seek case by case solutions.

Recent years have seen increasing use of atmospheric radionuclides for dating and tracing hydrogeologic processes. Hydrologists often assume that meteoric sources of these nuclides are dominant in ground water and that age-dating methods are limited primarily by analytical detection capability. However, in some cases, subsurface production may also limit the usefulness of these nuclides for dating. Equilibrium radionuclide concentrations are calculated as a function of depth for a variety of rock types. Production mechanisms include fissioning of heavy radionuclides; spallation by cosmic-ray nucleons; capture of neutrons, a-particles, muons and protons; and photonuclear reactions. Calculations indicate that deep subsurface production of ³H, ¹⁴c, ⁸⁵Kr and ⁹⁹Tc is generally below detection but that deep production of ³⁶C1, ³⁹Ar, ⁸¹Kr and ¹²⁹I establishes limits to age-dating of water in most rocks. Parameters for estimating production of ¹⁰Be, ²²Na, ²⁶Al, ³⁷Ar, ³²Si, ⁴¹Ca and ⁷⁹Se are included in appendices. Evidence for in-situ production of ³⁶C1 and ¹²⁹I is presented for two field studies. Concentrations in ground water from the Stripa granite, Sweden, were determined by accelerator mass spectrometry. ¹²⁹I values range from 1,000 to 200,000 atoms/ml, compared to an estimated background concentration in pre-1945 water of 20 atoms/ml. The high levels are attributed to production by spontaneous fission of ²³⁸U in the granite (44 ppm U). ³⁶C1/C1 ratios range from 50-200 x 10 -15 compared to about 40 x 10⁻¹⁵ in meteoric recharge. An increase in ratios with depth has been attributed to production of ³⁶C1 by neutron- capture on ³⁵C1 and is used to set upper limits on the residence time of water in the granite. The validity of using ³⁶C1/C1 ratios as a monitor of deep lithospheric neutron fluxes was tested by measuring the ratios in Cl extracted from Stripa granite. The average ratio, 190 x 10⁻¹⁵, agrees with ratios calculated based on rock chemistry, 190 x 10⁻¹⁵, and on the measured neutron flux, 220 x 10⁻¹⁵. ¹²⁹I and ³⁸C1 were also measured in uranium ores from the Koongarra and Ranger deposits, N.T., Australia. Samples from the oxidized ore zone contain only 6-23% of the ¹²⁹I contents predicted for equilibrium, suggesting preferential loss of ¹²⁹I relative to U during weathering. ³⁶C1 is produced as a result of high neutron fluxes in the ore. Measured ³⁶C1/C1 ratios range from 3 x 10 -12 to 1 x 10⁻¹⁰, corresponding to apparent neutron fluxes of 2 x 10⁵ to 1 x 10⁷/cm²/yr.

Geology and tunnelling was given by the U.S. Department of Energy (DOE) as the most important criteria in siting the SSC. The impact of ground water on construction and vice-versa is an important part of a sites geologic and tunnelling attributes, and its potential environmental impacts. Because of the site's undeveloped nature, only limited reconnaissance-type investigations of the regions hydrogeology had occurred prior to the siting of the SSC. To overcome this ignorance geological, geotechnical, and geophysical characteristics of the site were used to describe the hydrogeology. A hydrologically ideal site would lie above any aquifers, have little or no surface water interaction, and yet, have an adequate and reliable supply of good quality water nearby. The Maricopa site possesses all of these characteristics while apparently being absent of subsidence due to ground-water withdrawal.

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The treatment of potable water in Vars, ON is accomplished by filtering the colored, iron-laden groundwater through granular activated carbon (GAC) filters. When first installed, these filters unexpectedly experienced chromatographic displacements of iron into the produced water which resulted in orange-brown water at consumers’ taps. The treatment plant was later modified by adding potassium permanganate oxidation and a greensand filter prior to the GAC adsorption columns. Consequently, iron was almost completely removed and no longer caused operational problems. The main objective of this dissertation is to study the interactions between natural organic matter (NOM) and iron that caused the observed chromatographic effect. This study was divided into three main stages: a) characterization study on Vars groundwater and its treatment system; b) study of the competitive adsorption of iron with NOM in Vars groundwater; and c) evaluation of the rapid small-scale column test (RSSCT) for predicting the full-scale GAC column breakthroughs. The characterization of Vars groundwater showed that ferrous iron was found to be the dominant iron species, representing 90% of the total iron, and that 15 - 35% of the iron was complexed with NOM. It was hypothesized that the chromatographic displacement of iron from the GAC columns was caused by NOM-iron complexes; however, field mini-column experiments showed this was not the case. Thus, competitive adsorption between iron and NOM was seen as the more likely cause of the chromatographic effect. The adsorption capacity of ferrous iron in Vars raw water was less than that in organic-free water by a factor of 7 due to the competition with NOM over the GAC adsorbing sites. However, the NOM adsorption capacity was not reduced due to the presence of ferrous iron. It was hypothesized that ideal adsorption solution theory (IAST) models, which have been successful in describing competitive adsorption between target organic compounds and NOM, could model the competition between an inorganic compound such as ferrous iron and NOM. The hypothesis was proved to be correct, and the adsorption isotherm of iron in competition with NOM in Vars groundwater was simulated very well by several versions of the IAST model. However, none of the models were capable of simulating the competitive adsorption of NOM and ferrous iron simultaneously. Since the presence of iron did not significantly reduce the adsorption capacity of NOM, a simplified approach of using the single-solute NOM isotherm to represent the competitive NOM isotherm was recommended. The performance of the rapid small-scale column test (RSSCT) was evaluated in order to simulate the iron chromatographic effect observed at Vars’ full-scale GAC column. The RSSCT was not capable of predicting the iron phenomenon and the test proved to be problematic due to the oxidation and precipitation of iron within the small voids between the small-scale column’s GAC particles. The RSSCT, using constant and linear diffusivities, were applied to simulate the NOM adsorption after greensand treatment. Integrating both diffusivities, the tests predicted the onset and slope of the NOM breakthrough up to 10-L water treated/g GAC, which is equivalent to 250 days of operation time for the full-scale column. However, the NOM breakthroughs deviated beyond that point and the RSSCT using constant diffusivity underestimated the column performance greatly. On the other hand, the linear diffusivity RSSCT underestimated the performance to a lesser degree and its NOM breakthrough was quite parallel to the full-scale performance with lower NOM removals of 15%. The higher long-term NOM removal in the full-scale system may be explained by biodegradation, a phenomenon that was not considered by the short duration of RSSCT.