Now showing items 8962-8981 of 20306

    • Hydrogen, Carbon, and Oxygen Stable Isotope Geochemistry Applied to Paleoaltimetry and Paleoenvironmental Reconstructions in Northern Chile and Eastern Ethiopia

      Quade, Jay; Jimenez Rodriguez, Jhon Sebastian; Carrapa, Barbara; DeCelles, Peter G.; Tierney, Jessica E. (The University of Arizona., 2020)
      This dissertation explores the potential of stable isotope geochemistry in determining (1)the elevation history in the Central Andes of northern Chile and (2) the environmental conditions in the Southern Afar Rift in northeast Africa since the late Miocene. The Central Andes has been the focus of multiple studies that investigate the relationships between surface uplift and the mechanisms responsible for mountain building, as well as the link between high topography and variations in the regional climate. This study addresses the elevation history of the Western Cordillera in northern Chile at ~18.5-19.5ºS by using the hydrogen isotopic composition of hydration waters in volcanic glass, U-Pb dating in zircons, and sedimentologic observations. This region encompasses >1000 m of fluvial and lacustrine sediments deposited since the late Oligocene. The paleoaltimetry reconstruction based on the isotopic results indicate that high elevations (> 4 km) were reached at least since the early Miocene. This information helps to complete the paleoelevation record for the Altiplano at this latitude, providing an improved test of previously proposed explanations for surface uplift in this sector of the Andes. The comprehensive paleoaltimetry record of the Altiplano also provides key constraints to evaluate the role of high topography in the development of dry conditions in the Atacama Desert. A cross-comparison between the C-O isotopic data from carbonates and the isotopic results from volcanic glass helps to evaluate the effect of recrystallization and evaporation in modifying the isotopic signal of proxies for past elevations. This study addresses this subject by using the oxygen and carbon isotopic composition of carbonates, clumped isotope-based paleotemperatures, petrographic and sedimentologic observations, as well as major element abundance (ICP-MS and microprobe analyses). Finally, this study explores the use of hydrogen isotopic values in volcanic glass to paleoenvironmental reconstructions in the southern Afar region of Ethiopia in northeast Africa. This study presents 63 new hydrogen isotopic analyses from volcanic tuffs deposited in the past 6.4 My. The hydrogen isotopic results are considerably lower than those predicted to be in isotopic equilibrium with modern meteoric waters. When compared with the record from other proxies for past climate in northeast Africa, including hydrogen isotopic values from leaf waxes and oxygen isotopic values from soil carbonates, these results indicate that volcanic glass is preferentially hydrated during episodes of higher rainfall that feature lower isotopic values than that of mean annual rainfall.
    • Hydrogeochemical Evolution of Basinal Fluids in the Paradox Basin: Implications for Sources, Paleofluid Flow, Residence Time, and Water-Rock-Gas-Microbe Interactions

      McIntosh, Jennifer; Kim, Jihyun; Meixner, Thomas; Guo, Bo; Ferguson, Grant (The University of Arizona., 2022)
      Understanding evolution of paleofluid flow through the Earth’s shallow crust is important for water, mineral, and energy resource management, including extraction of subsurface resources and storage of alternative energy and waste products. The migration of water, gas, and life between surface and deep subsurface systems and its consequence by water-rock-gas-microbe interactions can be evaluated by characterizing hydrogeochemical features of fluids (e.g., formation water and natural gas) in sedimentary basins. This study focuses on the Paradox Basin in the Colorado Plateau, which has iconic manifestations of multiple episodes of paleofluid flow, including widespread sandstone bleaching, ore mineralization (e.g., Cu; U; Fe; Mn), and hydrocarbons, CO2, and He accumulation. Based on molecular and isotopic signatures in formation water and natural gas samples, the origin, types, composition, distribution, and residence time of remnant fluids in the Paradox Basin have been evaluated to constrain the hydrochemical and geological histories responsible for paleofluid flow and solute transport. Highly evaporated paleo-seawater derived brines (i.e., connate brines), associated with the Pennsylvanian Paradox Formation evaporites, migrated into adjacent under- and/or over-lying formations through faults by compaction. These H2S- and hydrocarbon-bearing reduced, saline fluids were responsible for much of the sandstone bleaching in overlying Triassic-Cretaceous shallow sediments, forming reduced traps for later Cu and U deposition. Natural gas throughout the basin is primarily thermogenic in origin recording different thermal maturities of gas generation. Microbial methanogenesis may have been inhibited by the deep burial history of the Paradox Basin and abundance of sulfate. Salt dissolution above and below the evaporites, by topographically-driven meteoric recharge, provided a source of more oxic, sulfate-rich shallow brines. Deep meteoric circulation (up to 3 km depth in the last 1.1 Ma, based on 81Kr dating), in response to the recent denudation of the Colorado Plateau (<4-10 Ma), contributed to flushing of residual brines in aquifers above and below the evaporites and biodegradation of hydrocarbons in shallow reservoirs (based on molecular and isotopic signatures of hydrocarbon in natural gas, including clumped isotopes of methane). The origin, types, and distribution of existing fluids in the Paradox Basin provide important constraints to understand the evolution of paleofluid flow and subsequent water-rock-gas-microbe interactions recorded in sedimentary rocks over geological time.
    • The hydrogeochemical evolution of the groundwater of the Tucson Basin with application to 3-dimensional groundwater flow modelling.

      Kalin, Robert M.; Long, Austin; Davis, Stanley N.; Bassett, Randy L.; Damon, Paul E.; Ruiz, Joaquin (The University of Arizona., 1994)
      This work examines the hydrogeochemical evolution of Tucson basin groundwater, including isotope hydrology, geochemistry and age determinations. Results of mineralogic investigation on basin fill were used to constrain water-rock geochemical reactions. Examination of 45 years of water quality data shows that groundwater mining has affected water quality. Stable isotopes of carbon, oxygen, hydrogen, sulfur, and chlorine and radiocarbon, tritium and radon determinations refine the interpretation of hydrogeochemical evolution of Tucson basin groundwater as modelled with NETPATH. Two distinct sampling periods, the first in 1965 and the second between 1984 and 1989, resulted in the determination of groundwater ages for water mined two decades apart. Isotope hydrology and geochemical modelling suggest that much of the water presently mined from the Tucson basin has a component recharged during the last 50 years. Increased sulfate concentrations suggest that heavy pumping in the northeastern basin may have induced increased leakage from lower units. Results of geochemical modelling indicate an average of 5 percent mountain-front recharge to the Ft. Lowell Formation along the northern aquifer margin. An increase in dissolved solids along the basin margin implies that this component to recharge has increased in the past decade. The radiocarbon age of the basin groundwater was compared with the temporal movement of water as modelled with MODFLOW and PATH3D. In general, the hydrologic simulation agrees with both the distribution of tritium and the exponentially modelled water age, as determined with bomb-derived radiocarbon, for areas of the Tucson basin that contain water less than 50 years in age. Hydrologic modelling failed to predict the antiquity of recently sampled water in the central basin but is similar to age determinations on waters collected in 1965.
    • The hydrogeochemistry of recharge processes and implications for water management in the southwestern United States

      Vandemoer, Catherine,1955-; Fogel, Martin M.; Lehman, Gordon S.; Wilson, L. G.; Long, Austin; Norton, Denis L. (The University of Arizona., 1988)
      A geochemical approach to the evaluation of the chemistry of natural recharge processes in the Tucson basin was used to identify the major minerals controlling the evolution of ground water chemistry and to assess the viability of recharging imported Central Arizona Project water supplies. Well cuttings analyses and water quality samples from over 65 wells in the basin were used as input to the geochemical computer model PATH4 (Helgeson, 1970) and the sequence of aqueous species and mineral production in a recharge reference volume examined. The study reveals that natural processes in the basin lead to the increase in dissolved solids content in ground water over time and the production of secondary minerals such as calcite, calcium montmorillonite, kaolinite and poorly crystallized alumino-silicate phases. Secondary minerals grow into aquifer pore spaces and may, over time, be responsible for the reduction in aquifer porosity and the specific capacity of wells. The recharge of imported Central Arizona Project water will lead to an increase in the dissolved solids content of ground water and may, in certain areas of the basin, lead to the enhanced production of secondary minerals. The use of CAP water as a recharge source must be guided by the geochemical factors which influence the nature and scope of reactions between CAP water and the Tucson aquifer matrix. The study demonstrates the need for and identifies water quality and aquifer matrix criteria for the assessment of sources of recharge water and recharge facility sites. The use of geochemistry as a tool for quantitatively assessing ground water quality is demonstrated.
    • Hydrogeochemistry of stream channel recharge of sewage effluent, northwest of Tucson, Arizona

      Esposito, David M.; Titley, Spencer R. (The University of Arizona., 1993)
      This investigation has documented the water quality impacts of stream channel recharge of sewage effluent northwest of Tucson and has evaluated the hydrogeochemical mechanisms potentially responsible for observed water quality changes. The evaluation was accomplished partly through construction of twelve monitor wells and implementation of a quarterly water quality monitoring program for surface water and groundwater. Constituents monitored included major inorganic chemical constituents, trace inorganics, trace metals, priority pollutants/trace organics and microbiological contaminants. ¹⁵N also proved useful in the study. The significance of a reducing zone immediately beneath the bed of the Santa Cruz River with respect to denitrification was documented. Findings of this investigation indicate that while sewage effluent is of poor quality with respect to drinking water standards, groundwater recharged by sewage effluent is of improved quality. Other findings include: * Nitrate in shallow groundwater near the Santa Cruz River in the Cortaro area appears to be primarily from stream channel recharge of sewage effluent; * Nitrate-N contents of effluent recharged groundwater averaged about 5 mg/1, well below the maximum contaminant level for drinking water of 10 mg/1, representing a 75 percent loss in total nitrogen during stream channel recharge of sewage effluent (assuming no mixing); * Both stream channel recharge of sewage effluent and agricultural deep percolation contribute to nitrate in shallow groundwater near the Santa Cruz River in the Marana area; * The reducing zone beneath the Santa Cruz River may be responsible for denitrification losses of up to 5 mg/1 of nitrate-N. This would explain approximately 30 percent of nitrogen losses, on average, between effluent and recharged groundwater; * The mechanisms of cation exchange and mixing with groundwater from other sources can explain the major changes in water quality between effluent and groundwater with respect to major inorganic chemical constituents; * Renovation of effluent with respect to coliform bacteria and enteric viruses content during recharge is not complete.
    • Hydrogeologic Controls, Initiation, and In-Situ Rates of Microbial Methanogenesis in Organic-Rich Reservoirs: Illinois Basin, U.S.A.

      McIntosh, Jennifer C; Schlegel, Melissa; Meixner, Thomas; Baker, Victor; Martini, Anna M. (The University of Arizona., 2011)
      Microbial methane from subsurface organic-rich units such as coals and shale support approximately 5% of the United States and Canada's energy needs. In the deep subsurface, microbial methane is formed by the metabolism of primarily CO2, H2, and acetate by methanogens. These metabolites are the by-products of multi-step biodegradation of complex organic matter by microbial consortia. This study investigates microbial methane in the Illinois Basin, which is present in organic-rich shallow glacial sediments (surficial), Pennsylvanian coals (up to 600 m depth), and the Upper Devonian New Albany Shale (up to 900 m depth). Findings from the study show that hydrogeochemical conditions are favorable for methanogenesis in each reservoir, with a decrease in groundwater flushing rates corresponding to a decrease in average reservoir depth and an increase in carbon isotopic fractionation. The deeper reservoirs (coals and shale) were paleopasteurized, necessitating re-inoculation by methanogens. The microbes were likely advectively transported from shallow sediments into the coals and shale, where areas of microbial methanogenesis correlate with freshwater recharge. The recharge in the shale was primarily sourced from paleoprecipitation with minor contributions from glacial meltwater during the Pleistocene (4He ages). All areas sampled in the shale were affected by Pleistocene recharge, however groundwater ages in areas of microbial methanogenesis are younger (average 0.33 Ma) than areas with thermogenic methane (average 1.0 Ma). Estimates of in-situ microbial methane production rates for the shale (10-1000 TCF/Ma) are 104-106 times slower than laboratory rates. Only limited biodegradation is observed in the shale. In-situ stimulation of methane production may be most effective if aimed at increasing production of the supporting microbial consortia as well as methanogens. Trace metal concentrations in the shale are below known levels of inhibition or enhancement, with the exception of Fe, suggesting that microbial methanogenesis is not repressed by any of the measured trace metals and may be improved with the addition of Ag, Co, Cr, Ni, and Zn.
    • The hydrogeologic framework of the Roswell groundwater basin, Chaves, Eddy, Lincoln, and Otero Counties, New Mexico

      Havenor, Kay Charles, 1931-; Titley, Spencer R.; Quade, Jay; McCullough, Edgar J.; Parrish, Judith T.; Glass, Charles (The University of Arizona., 1996)
      Aquifers of the Roswell groundwater basin are unconfined and confined types in Permian San Andres Formation and Artesia Group carbonates and evaporites, and the shallow unconfined Quaternary sedimentary and alluvial aquifer. The carbonate-evaporite aquifers were developed from solution by meteoric water, groundwater, the Pecos River, and its tributaries. The structural geology of the region includes Cenozoic folding and wrench faulting. Regional dextral strike-slip faults, <30 Ma to as young as 0.5 Ma, dominate the hydrogeologic framework of the groundwater basin. The faults created major lithologic and structural boundaries for the groundwater systems developed between them. The Roswell groundwater "basin" is actually a series of en echelon structural blocks with aquifers developed in erosion-beveled, fault-displaced Permian carbonates and evaporites partly covered by Quaternary sedimentary rocks and alluvium. The confined portions of the carbonate aquifers are in the San Andres Formation, the Artesia Group, or a solutional-karstic melange of the two. The Permian aquifers developed within each structural block exhibit different hydrochemical and hydrologic properties. The rock groups produce distinctive bulk element water chemistry signatures which are readily visible on ternary plots, Piper diagrams, and Fingerprint diagrams. San Andres Formation waters have high HCO₃⁻, intermediate SO₄²⁻ , and low Cl⁻ that demonstrate a preponderance of carbonates with some evaporites. Waters hosted by the Artesia Group are characterized by low HCO₃⁻, high SO₄²⁻ , and high Cl⁻that reflect evaporites with some carbonates. Quaternary alluvial aquifer waters show low Ca²⁺, low HCO₃⁻, with moderately high SO₄²⁻- and Cl⁻. Normative mineral reconstructions identify the lithologic combinations through which the waters flowed to acquire their present chemical characteristics. Plotted as charts the normative mineral reconstructions can be correlated as are electric well logs. Mineral stability diagrams support exchange by sodium liberation and calcium replacement in Na-smectite marine clays for altering the Ca⁺ - Na⁴ groundwater chemistry. Hydrochemical plots provide a robust means of identifying aquifer sources of groundwater and delineating their structural and stratigraphic boundaries. The work should be expanded to include more water analyses from each group, and as a means to identify unknows, such as the sources of water to the Pecos River.
    • A hydrogeologic study of an unstable open-pit slope, Miami, Gila County, Arizona.

      Earl, Thomas Alexander,1941-; Harshbarger, John W.; Mayo, Evans B.; Bull, William B.; Call, Richard D.; Lacy, William C.; Abel, John F. (The University of Arizona., 1973)
      An unstable slope in an open-pit copper mine in Arizona was analyzed after a 250,000-ton slope failure had occurred. Data on all available time-dependent hydrogeologic factors were analyzed utilizing multiple regression techniques in order to build a mathematical model of the slide displacement. This allowed determination of those factors which were most influential in promoting instability. It was determined that a ground-water rise of approximately one foot, and rainfall in the week prior to the failure, were the most important factors contributing to this particular slide. This is believed to be due primarily to an increase in cleft-water, or hydrostatic, pressure, with seepage forces contributing a significant but relatively constant shear component. Because instability was observed to extend beyond the original slope failure, a dewatering analysis was undertaken. A steady-state finite element flow system model series was developed by progressively incorporating subsurface information, as well as water table location. The ground-water flow system within the granitic host rock was then simulated as a continuum, and a flow net derived. Analysis of this flow net, combined with known ground-water discharge into the open pit, comprised the basis to estimate the coefficient of permeability to be approximately 4 gallons/day/foot². This value was then utilized in a preliminary dewatering analysis incorporating standard aquifer equations to predict possible drawdowns. The computed drawdowns suggest that pumping rates on the order of 10 gallons/minute/well from a line of 12 wells spaced 50 feet apart would produce approximately 100 feet of drawdown after 1 year of pumping. Results of stability analyses for various ground-water levels indicated that when the water table is lowered by dewatering, a steeper slope could be maintained in the open pit. Such steepening could be as much as 1° when the water table is lowered one-half to one-quarter the height of the slope (135 feet), and approximately 4½° when the slope area is completely drained.
    • Hydrologic effects of vegetative practices on ponderosa pine watersheds in Arizona

      Lopes, Vincente L.; Gay, Lloyd W.; Bustamante Gonzalez, Angel (The University of Arizona., 2000)
      Impacts of vegetation manipulation treatments on the hydrologic regime of ponderosa pine watersheds in Arizona were evaluated in this dissertation. First, the Seasonal-Kendall test was applied to detect trends in the precipitation and water yield of the control watershed. Then the long-term implications of two levels of forest cutting (clear cut and strip cut with thinning) on the water yield of the treated watersheds were assessed by means of the traditional paired watershed method and plots of cumulative recursive residuals (CUSUM). CUSUM plots were proposed as a complementary tool to evaluate the duration of water yield changes following treatment. Next, BROOK90, a conceptual hydrologic model, was used to assess water yield changes of ponderosa pine watersheds associated with vegetative practices. The model was optimized and verified in the control watershed to determine if the model was applicable to the environment where the experiment was conducted. Then the model was optimized for the pre-treatment period of the treated watersheds and the optimized parameters were used to simulate the water yield of the post-treatment period. Finally, results obtained with the traditional paired watershed approach were compared with those obtained with the modeling simulation. The two methods were in reasonable agreement.
    • Hydrologic mechanisms and optimization of in-situ copper leaching : case study-BHP Copper, San Manuel, Arizona

      Williamson, Christian Thoreau.; Neuman, Shlomo; Bassett, Randy; Orr, Shlomo; Poulton, Mary; Wang, Fei-Yue (The University of Arizona., 1998)
      In-situ copper leaching at BHP Copper's San Manuel open pit mine was established in 1986. Currently, over a thousand wells on the benches of the open pit mine are simultaneously injecting and pumping sulfuric acid solutions. A large-scale reconfiguration of the well field in 1996 led to a dramatic, yet temporary, increase in copper pounds, apparently due to changes in flowpaths. While the first reconfiguration was accomplished by means of hydrologic intuition, a question arose regarding the issue of whether subsequent reconfigurations supplemented with additional smaller scale characterization could ultimately lead to increased copper production. To study this question, two fifty-well sites were selected within the in-situ leach well field. Because in-situ leaching involves the movement of fluid within the subsurface, hydrology is a natural context in which to study the process. The desire to optimize well-to-well in-situ leaching for enhanced copper recovery through the fundamental understanding of important hydrologic mechanisms is the primary motivation for this dissertation. Hydrologic testing in San Manuel is inherently challenging due to the hydraulically dynamic environment. A hydraulic cross-hole testing procedure termed "Cyclic Pulse Testing" (CPT) was used to overcome this issue. Over 100 pressure responses obtained via CPT at the two test sites were examined by means of type curve analysis. The spatially distributed hydraulic parameters were analyzed within the framework of geostatistics. The kriged heterogeneous hydraulic conductivity fields were inputted into a numerical flow and transport model to study, along with other issues, the impact heterogeneity has upon the in-situ leaching process. A number of conclusions were reached based upon the investigation of the two test sites. Comparison between single-hole and cross-hole hydraulic tests revealed the probable presence of a low permeable skin surrounding the wells. By far, the most important hydrologic mechanism controlling the in-situ leaching process in San Manuel was the massively induced hydraulic background gradient, in places, on the order of 35°. Modeling revealed insignificant differences on the sweeping efficiency of the formation between heterogeneous and homogeneous simulations. However, due to the twodimensional nature of the collected data, additional three-dimensional information may lead to a different conclusion.
    • Hydrologic model selection in a decision making context

      Lovell, Robert Edmund,1921-; Duckstein, Lucien; Baker, Robert L.; Schultz, Donald G.; Lomen, D. O. (The University of Arizona., 1975)
      The problem of selecting appropriate mathematical models for use in studying hydrological phenomena has created a situation in which the choice of suitable models by hydrologic practitioners has become exceedingly complex. The extensive comments in the literature indicate that neither the traditional system of technical journals nor the more modern computer-based retrieval schemes have really solved the problem. Further examination shows that similar problems have arisen in many fields, hence a well organized attack on the specific problem of hydrologic model choice can have a more general application. The present problem is identified as a requirement to codify and make accessible to users information in a more directly user oriented format. The problem of model choice arises at several levels, ranging from decision on what fundamental structure to use, to choice of parameters, and on to model calibration and validation. This paper is focused on a scheme to aid in model structure choice. The essential ingredients of model structure choice, and indeed of many choice processes, are extracted and embedded in a generalized set theoretic mathematical notational framework in order to give some insight into the nature of the problem. Within this framework the specialized features of the model choice problem are analyzed, and a specialized model is developed for assisting in model choice and all problems similarly situated. These considerations lead to the development of a finite vector of objective statements with codified responses prepared by a panel of qualified researchers who are willing and able to construct the essential information in a user oriented format. It is required that the panel not only couch their information in objective oriented terms but that they also generate value judgments for the individual components. In this way, those using the system can take advantage of the expert opinions embedded in the model while, at the same time, tailoring the choice to meet their own specific needs and aspirations. This results in what is defined as a mathematical CHOICEMODEL. The implementation of a system for interactive computation of the CHOICEMODEL is described in detail, and the associated computer programs are presented in appendices. A detailed instruction manual is given, and the implementation of the method is illustrated by an easily understood model of the ingredients of the problem of selecting an 8-track stereo tape deck for home use. The plan is outlined whereby hydrologic choice models can be developed within the CHOICEMODEL system by a selected panel of expert EVALUATORS.
    • Hydrologic modeling for flood control detention basin design and operation.

      Smiley, Mark Andrew.; Davis, Donald R.; Ince, Simon; Buras, Nathan; Young, Kenneth (The University of Arizona., 1994)
      This dissertation presents a methodology for hydrologic modeling related to the design and operation of flood control detention basins. Prior to this document, a comprehensive, tractable methodology for detention basin hydrologic modeling did not exist. Furthermore, techniques used in the past have not always taken advantage of computer technology or recent advances in the field of hydrology. New and original methods are presented and are developed from personal experience, recent literature, and relevant courses at The University of Arizona. Chapters in this document include precipitation data analysis, detention basin stormwater inflow, detention basin sediment inflow, stored water losses through evaporation and infiltration, design issues, and operation under competing water use objectives. Engineering constraints and data availability are explicitly addressed throughout the methodology. The goal is to determine hydrologic variables for detention basin design such as active storage volume, spillway capacity, drain outlet capacity, and, additionally for some systems, the bypass channel capacity and side-weir threshold spill flow rate. In addition to providing an increased level of protection from flood damage, detention basins may also accommodate land use and water conservation objectives of urban society.
    • A hydrologic system analysis of the ground-water resources of the western desert, U.A.R. (Egypt)

      Salem, Mohamed Halim; Shibtzke, Herbert E.; Harshbarger, John W.; Ferris, John G.; Simpson, Eugene S.; Smiley, Terah L.; Peterson, Dennis (The University of Arizona, 1965)
      An analysis of the cause-effect relationship of a free water table aquifer that changes laterally to an artesian aquifer was made for regions bounded internally by a circular cylinder. For a hydrologic system with a large pressure-head energy, development of the water resource by a single well is not the most practical approach and thus the study was extended to solve the problem of a line array of wells. The flow characteristic of the hydrologic system was divided into a regime of flow near the line array of wells which is titled the conduit regime, and a regime of flow distant from the line array, which is called the reservoir regime. This classification of flow type is based on the fact that the storage coefficient is not constant and accordingly the hydraulic diffusivity of the aquifer in the conduit region is much smaller than that in the reservoir region. Therefore, the mathematical continuity, which was assumed in previous analyses by other authors becomes discontinuous because linearity does not prevail throughout the flow system. The superposition principle, which is based on linearity and homogeneity, can not be applied to this non-linear system. By subdividing the flow system into the two regimes of conduit and reservoir, Carslaw's solution for the circular cylinder may be amplified by two integrations to achieve mathematical continuity of the whole system. The range that Goldenberg solved analytically for a similar problem was extended to meet practical requirements in the field of ground-water hydrology. A new approach was developed for the solution of the mutual interference problem of an infinite line array of wells. The interference is expressed in terms of what is called the discharge efficiency factor. The findings were applied to a hydrologic analysis of the ground-water resources of the Western Desert, U. A. R. (Egypt) in or der to describe its significance and importance in the design of systems for water resources development in extensive aquifers. The results aid also in defining the applicability limits of the theory of images, which has been used by several authors to solve for the interference problem of an infinite line array of wells.
    • Hydrologic, social and legal impacts of summary judgement of stockwatering ponds (stockponds) in the general stream adjudications in Arizona

      Young, Don William.; Bradley, Michael D.; Evans, Daniel D.; Ince, Simon; Hawkins, Richard H. (The University of Arizona., 1994)
      General water rights adjudications are now taking place in Arizona. The Gila River and Little Colorado River adjudications are among the largest court proceedings ever undertaken in the United States, involving more than 78,000 water rights claims scattered over 50,000,000 acres of land. The cost of individually proving such a number of individual claims in a formal trial setting would be enormous — often greater than the water's economic worth. Also, the time required to complete such a proceeding would take decades. Consequently, alternative procedures are needed to streamline the investigations and forestall a potentially serious water resource management problem. There are an estimated 22,800 stockwatering ponds (stockponds or stocktanks) in the Gila River Basin alone, and each potentially could be tried as an individual case. If small claims such as those for stockwatering could be considered de minimis in their impact on other higher priority uses, they might be adjudicated as one class of use, thereby fore-stalling a case-by-case trial of each individual water right claim. However, a major obstacle in granting special treatment to small claims lies in demonstrating to litigants that certain small water uses do not, in fact, have a discernible impact on other downstream water right holders. This study was undertaken to quantify the actual losses to a river system from stockwatering ponds, and to compare those losses to other naturally occurring impacts on the hydrologic system. Employing a watershed model, portions of the Walnut Gulch Experimental Watershed at Tombstone, Arizona, an area located within the San Pedro watershed, were analyzed. Storm runoff was simulated with and without the presence of stockponds. Different storm events and storage conditions were modeled in order to measure the impact of stockpond storage under a wide range of field circumstances. This study demonstrated that the hydrologic effects of stockwatering ponds are de minimis with respect to their impact on other water users many tens or hundreds of miles downstream on the river system. Stockpond numbers, capacities, volume/surface area relationships, quantification methods, and effective retention are also evaluated. Statutes in other states are reviewed for their approach to handling stockwatering uses.
    • Hydrological and Biogeochemical Investigation of Semi-Arid Urban Catchments: Assessing Opportunities and Performance of Green Infrastructure

      Meixner, Thomas; Gupta, Neha; Gallo, Erika; Condon, Laura; Breshears, David (The University of Arizona., 2022)
      In arid and semi-arid environments such as the southwestern United States, water availability is the limiting factor in the stability and growth of environmental and human systems. This project addresses a fundamental challenge of cities located in semi-arid urban environments, where water managers must address the paradoxical issue of both drought and flooding. To address these challenges, cities such as Tucson, Arizona are implementing solutions such as green stormwater infrastructure in a decentralized manner throughout neighborhoods as street-scale basins and curb cuts with the goals of harnessing additional sources of water for societal use, reducing flood control issues, offsetting potable water use, and reducing urban heat island impacts. Taking advantage of the City of Tucson, Arizona as a living laboratory, this observational study investigates the opportunities and influence of green stormwater infrastructure on stormwater runoff and biogeochemical cycling on the urban subwatershed (neighborhood) scale via the development and analysis of runoff and hydrochemical datasets typically underrepresented in semi-arid urban environments, using a paired watershed study design. This project also invokes a coupled natural-human systems lens to characterize and evaluate the motivation, potential, and evolution of green stormwater infrastructure in Tucson. This study highlights the difficulties in assessing small-scale decentralized features influence on runoff responses in semi-arid urban watersheds with many complex and interacting landscape factors. The magnitude of differences of runoff response between the paired watersheds compared to the range of current green stormwater infrastructure implementation levels indicates there is likely a higher order control on this runoff response such as unlined channel reach between monitoring sites. Despite the short duration of storm runoff and the small watershed size, it appears that biogeochemical transformations like rapid soil microbial activity and respiration alter solution chemistry during episodic runoff. In addition, solute sourcing to runoff within the watershed area to the stream reach appear to contribute to changes in solution chemistry through solute additions. Investigations into the natural-human system of GSI in dryland cities describe a system in which a range of perceived benefits motivate a diverse set of stakeholders to collaborate and experiment with GSI implementation, leading to iterative changes in ecosystem provisioning and social learning.
    • Hydrological and Paleo-Drought Variability in the Winnipeg River Basin, Canada and the Canadian Prairies

      Evans, Michael N.; St. George, Scott; Evans, Michael N.; Meko, David; Betancourt, Julio; Overpeck, Jonathan; Hirshboeck, Katherine (The University of Arizona., 2007)
      Changing hydroclimatic conditions are the primary source of risk to hydroelectric power generation. The research described in this dissertation investigates hydrological and drought variability in the Winnipeg River basin, Canada, during the last several hundred years using instrumental hydroclimate data and paleoclimatic records derived from tree rings. The basin drains parts of northwestern Ontario, northern Minnesota and southeastern Manitoba, and is the most important component of the hydrological system used to generate power in Manitoba. Extreme low annual flows in the Winnipeg River are associated with enhanced meridional flow across western Canada during summer and autumn, which suppresses precipitation over the watershed and reduces runoff from spring snowmelt. In contrast to the declining flows observed for other regional rivers, mean annual discharge in the Winnipeg River basin has increased substantially since the early 1920s. For a longer perspective, fifty-four ringwidth chronologies (mainly Pinus resinosa and P. strobus) were used to assess changes in summer climate in the Winnipeg River region since AD 1783. Tree growth in this region is significantly, but weakly, correlated with both temperature and precipitation during summer. Synthetic tree-ring records produced by the Vaganov-Shashkin model of tree-ring formation are consistent with these relationships with climate, and suggest that the primary factor limiting tree growth switches from temperature to moisture in mid-summer. The Winnipeg River tree-ring record indicates that summer droughts were more persistent in the 19th and late 18th century than during the last 100 years, but there is no evidence that drought was more extreme prior to the onset of direct monitoring.This dissertation also examines past changes in summer drought over the broader region using 138 ringwidth records from the Canadian Prairies provinces and adjacent areas. Regional ringwidth signals are primarily related to summer moisture and drought conditions. These summer-sensitive records are not linearly related to major modes of climate variability, including ENSO and the PDO, which mainly affect the climate of western Canada during winter. Extended drought records inferred from regional tree-ring series indicate that drought on the Canadian Prairies has exhibited considerable spatial heterogeneity over the last several centuries.
    • Hydrology, hydraulics, and sediment transport of pleistocene Lake Bonneville flooding on the Snake River, Idaho

      O'Connor, Jim E.; Baker, Victor R.; Clark, Robert; Davis, Owen K.; Bull, William B.; Ince, Simon (The University of Arizona., 1990)
      Approximately 14,500 years ago, Pleistocene Lake Bonneville discharged 4750 km 3 of water over the divide between the closed Bonneville Basin and the watershed of the Snake River. The resulting flood, emanating from the divide at Red Rock Pass, Idaho, followed the present courses of Marsh Creek, the Portneuf River, and the Snake and Columbia Rivers before reaching the Pacific Ocean. For the 1100 kilometers between Red Rock Pass and Lewiston, Idaho, the Bonneville Flood left a spectacular array of flood features that have allowed for geologic reconstruction and quantitative evaluation of many aspects of the flood hydrology, hydraulics, and sediment transport. Geologic evidence of maximum flood stages in conjunction with step-backwater modeling provides for peak discharge estimates and understanding of local hydraulic flow conditions for ten separate reaches along the flood route. Peak discharge was approximately 1.0 million m³•sec⁻¹ at the Lake Bonneville outlet near Red Rock Pass. Downstream, the maximum discharge had attenuated to 0.57-0.62 million m³•sec⁻¹ by arrival at Lewiston. Attenuation was primarily the result of flow storage in the wide alluvial valleys of the western Snake River Plain. The local hydraulic conditions (depth and velocity) of the Bonneville Flood varied significantly within and between the study reaches. The rate of energy expenditure was also highly varied; local calculated stream-power values ranged from less than 10 watts•m² to 100,000 watts•m². Greater than 60% of the total energy loss at peak discharge was expended in a total distance that encompassed less than 10% of the flood route. These spatial variations in local hydraulic conditions were profoundly important in controlling the distribution of flood processes and features. The deposition of tractively-transported cobbles and boulders (measured diameters ranged from less than 10 cm to greater than 10 m) occurred in reaches of decreasing flow energy within quantitatively-definable limits of flow energy. Areas of erosion are more difficult to precisely evaluate; however, they were restricted to reaches of greater stream power. It is likely that cavitation was an important erosional agent in many areas of most intense flow conditions.
    • Hydrometeorological Variability over Pakistan

      Gupta, Hoshin V.; Zeng, Xubin; Bashir, Furrukh; Gupta, Hoshin V.; Zeng, Xubin; Galarneau, Thomas J.; Hazenberg, Pieter (The University of Arizona., 2017)
      Pakistan, as an agriculture based economy, is vulnerable to various hydrometeorological hazards ranging from tropical cyclones, thunderstorms, tornadoes, drought, rain, hail, snow, lightning, fog, wind, temperature extremes, air pollution, and climatic change. However, three of the most pressing challenges in terms of water resource availability, that are different in nature, but are inter-linked to each other are discussed over here. We begin with the Karakoram Anomaly that is considered as one of the most mysterious and most speculated phenomena on Planet Earth. Though, it is confined to the glaciers in the eastern Hindukush, western Karakoram and northwestern Himalayan mountain ranges of Northern Pakistan that are not responding to global warming in the same manner as their counterparts elsewhere, because, their retreat rates are less than the global average, and some are either stable or growing. However, the Karakoram Anomaly has baffled scientific society for more than a decade since its earliest discovery in the year 2005. The reasons of the Karakoram anomaly were mainly associated to physiography of the area and role of climate was considered marginal till now, as climate is influencing glaciers differently all over the globe. Here, for the first time, we present a hydro-meteorological perspective based on five decades of synoptic weather observations collected by the meteorological network of Pakistan. Analysis of this unique data set indicates that increased regional scale humidity, cloud cover, and precipitation, along with decreased net radiation, near-surface wind speed, potential evapotranspiration and river flow, especially during the summer season, represent a substantial change in the energy, mass and momentum fluxes that are facilitating the establishment of the Karakoram Anomaly. In turn, it is influencing the availability of glacier melt in River Indus in summer season. Secondly, we developed a hydrometeorological data sets for Pakistan as they are extremely important for water related impact studies and future climate change scenarios. Presently, major sources of gridded temperature and precipitation data generation are in-situ observations, satellite retrieved information and outputs from numerical models. However, each has its own merits and demerits. Among them gridded observed data sets are considered superior if the gauge density is better. Unfortunately, precipitation gauge network of Pakistan is poorly presented in prior gridded products. Therefore, a daily in-situ observation based, 0.05º×0.05º gridded temperature and precipitation data set for Pakistan, for the period of 1960-2013 is developed. It is named as PAK-HYM-1.0, that is an abbreviation of Pakistan and Hydrometeorology, and 1.0 indicates that it is the first version. This data set is developed by utilizing data from 67 meteorological stations of Pakistan. This number of observation sites is 2 to 4 times higher than that used in prior similar products, and this product can be adopted as an operational information product that can be updated on daily basis. Finally, we focused on meteorological and hydrological droughts in Pakistan. We have reconstructed history of drought in Pakistan using in situ observations based high resolution gridded data through Standardized Precipitation Index (SPI) methodology on different time scales. Furthermore, we have explained the transition of meteorological drought to hydrological drought using river inflows data of large rivers of Pakistan, and explained the sensitivity of different rivers to rainfall and temperature of different seasons. On the basis of this analysis, we have proposed a solution of construction of water reservoirs to tap water resources from northern mountains as inflows from these mountains has potential to perform as a buffer against droughts in low-lying areas of Pakistan. In addition to that, we have demonstrated the potential of Palmer Drought Sensitivity Index (PDSI) as an operational tool for drought monitoring in Pakistan.
    • Hydropower on the Colorado River: Examining Institutions, Conflicts, and Consequences of Changing Dam Operations

      Bauer, Carl J.; Karambelkar, Surabhi; Schlager, Edella; Gerlak, Andrea K. (The University of Arizona., 2020)
      The Colorado River, one of the world’s most iconic rivers and a critical water source for over 40 million people, is going dry. A 20-year drought has left major reservoirs at perilously low levels, and the challenges of managing dams for competing water uses have become stark. In this heavily legislated, litigated, and regulated river, dams are operated on a legal priority basis: agricultural, municipal, and environmental water uses receive a higher priority over hydropower, which is an ‘incidental’ or lower priority water use. As water levels decline, dam operations continue to protect higher priority water uses; this impacts hydropower generation, yet the consequences of this impact remain poorly understood or accounted for in the decision-making calculus for drought management in the river basin. This omission is serious: it will produce inadvertent trade-offs and detrimental societal outcomes as the same laws that give hydropower its lower priority also create complex dependencies between higher priority water uses and hydropower generation. To address this omission, this research examines hydropower governance at the two largest and strategically important dams in the Basin: Hoover Dam and Glen Canyon Dam. The research in this dissertation is organized around two questions: How do water, environment, and energy laws and policies influence dam operations and hydropower generation in the Colorado River Basin? And, what are the consequences of changing hydropower operations in the Colorado River Basin? Through historical and comparative institutional analysis, archival research and semi-structured interviews with over four dozen key decision-makers and resource users, this research provides insights on how laws and policies have evolved in response to socio-environmental changes in the Basin and how they produce distinct past, contemporary, and future governance challenges and outcomes for hydropower at Hoover and Glen Canyon Dams. The research finds that a specific configuration of water and environmental laws has created significant constraints for hydropower operations and will more likely produce hydro-environmental conflicts at Glen Canyon Dam compared to Hoover Dam. The differences in generation constraints coupled with varying provisions in dam-specific energy laws and policies have also created more flexibility in responding to changes in hydrology and a rapidly evolving electricity sector at Hoover Dam than Glen Canyon Dam. This research also finds that institutional arrangements dictate how resource users are impacted by and can adapt to changes in hydropower operations in the Colorado River Basin and influence how users can respond to those changes. Power customers, water projects, and environmental programs connected to Glen Canyon Dam are more impacted than Hoover Dam due to changes in power generation and loss in hydropower revenues. This dissertation offers policy insights for decision-makers in the Basin to identify and minimize the ramifications of water management decisions for hydropower and water uses legally tied to this resource, such as by clarifying specific ambiguities in the law. This research also identifies policy recommendations and critical questions that require further attention to plan for a future without hydropower, such as by identifying alternative funding streams in the absence of hydro dollars. This dissertation contributes to scholarship on formal institutional arrangements in the Colorado River Basin by conducting a first in-depth comparative study of the institutional dimensions of hydropower generation. This dissertation also offers lessons and cautionary warnings for hydropower governance as well as institutional design under conditions of socio-economic and environmental change that are relevant for hydropower projects in the United States and beyond.

      CLARKE, MICHAEL. (The University of Arizona., 1986)
      The San Dimas mining district, including the Tayoltita mine, is a Tertiary silver-gold epithermal vein system deposited in a calcalkaline volcanic pile. Hydrothermal alteration and vein formation is temporally related to a granite batholith intruded into the volcanics. Alteration mineralogy in andesites is compatible with a hydrothermal flow model in which heated water rises through the batholith, cools to 260°C, and flows out into the volcanics. In the process, a(Na)⁺/a(H)⁺, a(K)⁺/a(H)⁺, a(Ca)⁺⁺/a²(H)⁺, a(SO₄)⁼.a²(H)⁺, and a(H₂S) increase; a(A1)⁺⁺⁺/a³(H)⁺ decreases; and a(Fe)⁺⁺/a² (H)⁺ remains constant, all relative to original fluid conditions in the andesites. Lateral elongation of Ag:Au ratio zoning plotted on vertical projections of veins is interpreted to reflect hydrothermal fluid flow principally in a horizontal direction during ore deposition. Quartz vein-filling, accompanied by chlorite, calcite, rhodonite, and adularia, is widest in a vertical interval approximately 500 to 1,000 meters below the original surface. Pyrite is widely distributed, but silver minerals, electrum, and base-metal sulfides are restricted to the upper portion of the vertical interval of veining in a zone termed the ore horizon. Paragenetic relationships among vein minerals of the Cinco Senores vein in the Tayoltita mine indicate that a(H₂S) decreased; a(Cu)⁺/a(H)⁺, a(Ag)⁺/a(H)⁺, and a(Au)⁺/a(H)⁺ increased; and a(Fe)⁺⁺/a²(H)⁺ and a(SO₄)⁼.a²(H)⁺ remained nearly constant during the initial stage of ore deposition. Fluid inclusion studies of quartz from the Cinco Senores vein indicate that ore deposited at an average temperature of 260°C from boiling fluids of apparent salinities ranging from 0.15 to 0.3 m(NaCl) equivalent. The greater apparent salinities probably reflect dissolved gases as well as chloride salts. Correlation of Ag:Au ratios in deposited vein with ice-melting temperatures in fluid inclusions suggests that evolution of ore fluids in space was accompanied by both increase in deposited Ag:Au ratios and decline in fluid solute concentration. Correlation of ice-melting temperatures with paragenetic age of associated quartz suggests that vein-depositing hydrothermal fluids evolved in both space and time from relatively concentrated to dilute conditions. Both boiling and mixing could have caused this decline in solute concentration.