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The influence of dissolved natural organic matter (NOM) on the transport of Cu(II) in saturated media was investigated in controlled batch and column experiments. Six sources of natural organic matter (two in their ambient solution matrices and four isolated humic substances) were chosen to represent different environments and different humic fractions. 5i02 and a-Al203 comprised the mineral surfaces with which the NOM and Cu(II) interacted. The experiments were conducted at a constant ionic strength and buffer concentration and at pH 6.2 (all sources) and pH 7.5 (two sources). Equilibrium Cu(II) concentrations were monitored with an ion specific electrode and atomic absorption spectrophotometer and NOM was measured as UV absorbance at 254 rim. Adsorbate effect on particle surface charge was evaluated using microelectrophoresis and the effect of molecular weight on NOM breakthrough was determined with ultrafiltration of column influent and effluent. Column studies showed significant variation in NOM breakthrough as a function of source on a mixed bed of SiO₂ and a-Al203. Humic acid from the Suwannee River showed greater adsorption than the fulvic acid from the same source. The presence of Cu(II) resulted in greater retardation of all the NOM sources than in the Cu(II) free systems. Cu(II) transport was slightly facilitated at pH 6.2 by the Orange County NOM and Biscayne aquifer NOM, while the other NOM sources inhibited Cu(II) movement. At pH 7.5 the Orange County and Biscayne Aquifer sources greatly facilitated the transport of Cu(II) in a mixed bed column. The results of this research suggest that the following mechanisms can influence trace metal transport in saturated media: 1) competition of the NOM with the mineral surface for metal complexation; 2) formation of mixed ligand complexes (metal-NOM-mineral surface); 3) complexation of Cu(II) by adsorbed NOM; and 4) metal bridging of NOM to a mineral surface. The results also show that cations commonly found in natural waters ,especially Ca(II) and Mg(II), can influence the interaction of trace metals and NOM with mineral surfaces.

A broad-based geochemical approach, including chemical and isotopic analyses of ground water, chemical analysis of aquifer materials, and laboratory water-rock experiments, was used to evaluate the origin and chemical evolution of ground water on La Palma, a volcanic island in the Canary Archipelago. Stable isotopes of oxygen, hydrogen, carbon and sulfur were successfully used to delineate recharge zones and identify solute sources. Laboratory study of water-rock interactions established the source of solutes and the nature of the chemical reactions that control ground-water chemistry. Most ground water on La Palma originates in a recharge zone that encircles the island from 500 to 1800 meters above sea level. Dry fallout and seaspray are minor sources of solutes, however, evaporative concentration during recharge may produce elevated chloride levels in some portions of the island. Laboratory water-rock experiments and ground-water analyses indicate that incongruent dissolution of aluminosilicate minerals is the dominant process of solute acquisition. The geochemical evolution of most waters is controlled by the availability of dissolved carbon dioxide gas. However, oxidation of pyrite enhances the reactivity of ground water in some portions of the island. Waters in the early phases of chemical evolution appear to be in equilibrium with a kaolinite alteration product, whereas more mineralized waters have compositions consistent with smectite equilibrium. Zones or compartments of ground-water flow were delineated by classifying sampling sites into geochemically distinct groups. Eight distinct zones of ground-water flow were identified using these criteria, including superimposed but hydrologically separate flow paths.

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.

This work describes a new taxonomy for elastic, sedimentary porous media. The taxonomy is synthesized for the investigation and characterization of ground-water flow from accumulating developments in the genetic analysis of elastic, sedimentary depositional structures. Genetic analysis recognizes spatial associations of elastic, sedimentary structures imposed during genesis. The taxonomy is a nested hierarchy of discrete elastic, sedimentary structures distinguished by the bounding surfaces created during their emplacement and rearrangement. The investigation and characterization of a specific ground-water flow system in elastic, sedimentary porous media can be improved by imposing a structural context on lithologie observations, geophysical measurements, head measurements, and hydraulic conductivity estimates. Globally-valid and transferable descriptions of structures in the taxonomy from modern exposures, outcrops, and densely sampled subsurface systems are modified to fit site-specific geologic observations and measurements. A specific procedure is developed for applying the taxonomy in the investigation and analysis of ground-water flow. The procedure quantitatively measures the hydraulic validity of alternative geologic interpretations of site-specific data under the taxonomy. The application of the taxonomy and procedure to a typical set of data types, densities, and quality is illustrated with data from a site of ground-water contamination investigation.

Stochastic two-stage programming, a main branch of stochastic programming, offers models and methods to find the optimal objective function and decision variables under uncertainty. This dissertation is concerned with developing an approximate procedure to solve the stochastic two-stage programming problem and applying it in relative field. Five methods used in evaluating the expected value of function for distribution problem are discussed and their basic characteristics and performances are compared to choose the most effective approach for use in a two-stage program. Then the stochastic two-stage programming solving method has been established with the combination of a genetic algorithm (GA) and point estimation (PE) procedure. This approach avoids the inherent limitations of other methods by using PE to estimate the expected value of recourse function and the GA to search optimal solution of the problem. To extend the advantage of GA the modified genetic algorithm (MGA) is built to improve the performance of GA. Finally, the whole procedure is used in several examples with different kinds of variable and linear or nonlinear style objective functions. A stochastic two-stage programming model for an aquifer management problem is set up with considering conductivity and local random recharge as the source of uncertainty in the system. The designed procedure includes the response matrix process that replaces the partial differential flow equation, Girinski potential process and a pre-setup process that makes the response matrix process application in general aquifer random field possible. Other chosen problems are solved with designed approach to illustrate the effects of uncertainty source in the stochastic programming model and compared with results with ones given in literatures.

Quantitative characterization of hydraulic conductivities of aquifers is of fundamental importance to the study of groundwater flow and contaminant transport in aquifers. A conditional approach is used to represent the spatial variability of hydraulic conductivity. Briefly, it involves using qualitative and quantitative geologic borehole-log data to generate a three-dimensional (3D) hydraulic conductivity distribution, which is then adjusted through calibration of a 3D groundwater flow model using pumping-test data and historic hydraulic data. The approach consists of several steps. First, classify the lithological information obtained from geologic borehole-logs into representative texture categories; second, establish a quantitative correlation between laboratory measured corescale hydraulic conductivities and texture; third, generate a 3D hydraulic conductivity distribution using a genralized kernel-estimator method; fourth, upscale the core-scale hydraulic conductivity values such that the vertically averaged value at each location matches the field-scale value estimated from pumping tests; and fifth, use hydraulic data to calibrate the 3D field-scale distribution to account for regional-scale characteristics. The approach is applied to a trichloroethene (TCE) contaminated large-scale Superfund site. Based on the good agreement between simula.tions and observations, the results are considered reasonable and realistic. A number of nonideal processes and factors may contribute to the decreasing contaminant removal rate observed at the site. Most of the quantitative analyses of nonideal transport behavior have been conducted using data collected from column or small-scale field experiments. Studies extending such analyses to regional-scale contaminant transport are rare. In this study, a fully 3D transport model is developed to evaluate the effects of various processes/factors on the regional-scale nonideal TCE transport. Based on the analyses, it is found that while large-scale heterogeneity of hydraulic conductivity and ratelimited desorption have significant impacts on TCE transport and cause some nonideal behavior, their impact is not sufficient to account for the extensive tailing exhibited by the observed concentrations in the groundwater entering the treatment plant. Rate-limited dissolution of immiscible liquid appears to be the most likely primary cause of the extensive nonideal transport behavior observed at the site. The impact of the nonlinear sorption and the local-scale heterogeneity on TCE removal appears to be insignificant.

Managing and protecting our water resources is one of the most pressing long-term issues facing Texas. In addition to population growth, Texas' vulnerability to drought makes long-term water planning both challenging and imperative. As competing interests vie for this limited natural resource, the State struggles to reach solutions that can provide sustainable water for everyone. This report, and the accompanying video, Tecolote, examine the management of Texas groundwater and the impact it has on Tecolote Farms. / text

Kuwait is an arid country situated at the head of the Arabian Gulf and its water resources can be classified into three significant types: (1) natural (groundwater) and (2) artificial (desalinated sea water and treated wastewater). In the absence of surface water bodies, groundwater constitutes the most important natural water resource in Kuwait with TDS [less than or equal to]10000 mg/L in central and south Kuwait. Only in the north can one find fresh water lenses. Brackish groundwater are used for irrigation, landscaping, construction work, non-potable use in households and mixing with desalinated water up to 10%, to make it potable. The occurrence of usable groundwater is limited to the Kuwait Group and Dammam Formation. Due to over-pumping of groundwater over the last few years, the levels and quality of groundwater are deteriorating. Kuwait is described as the poorest country in terms of water availability (UN World Water-2003). The current rates of water consumption are very high, with 459.6 L/C/d and almost 91 L/C/d for fresh and brackish water, respectively. The water budget of the water resources, represented as percentages is 59% from desalination sea water plants, 32% from groundwater with the possibility to increase the use of this resource and 9% from waste water reuse plants. Although Kuwait does not have any surface water, but it depends on technology to produce water recourses to meet the demand. The best solution for solve the issues of declining water levels and increasing salinity is artificial recharge. Artificial recharge has been applied in Kuwait in different groundwater fields since the 1980s. In addition, the available surface storage capacity of 11.7 Mm³ freshwater is sufficient to meet demand for about 7 days. So, Aquifer storage and recovery (ASR) can be used to store the water in aquifers instead of surface storage. ASR entails storing water in aquifers during wet times and recovering the water from the same well during drought times. Surface storage needs construction resources and vast land. In contrast, storing water in aquifer storage does not need that and it can decrease salinity and keep the water table constant. The water availability for artificial recharge can come from desalination and wastewater plant. The capacity and production of desalination plants are 1.425Mm³/day (525.125Mm³/yr) and 1.31Mm³/day (478.15 Mm³/yr), respectively from 5 stations. The excess capacity is 115000 m³ per day and could reach 290000 m³ per day in the winter season. Wastewater treatment plants produce from 3 plants around 0.337 Mm³/day (123.342 Mm³/yr) and the newest plant (operating by RO system) produces 0.32 Mm³/day (117.12 Mm³/yr) and will reach 0.643 Mm³/day (235.338 Mm³/yr) in 2015. The water produced from wastewater treatment plants has good quality and can be used for irrigation, greening enhancement, landscaping, recreation (artificial river and lakes) and artificial recharge. Also, using water treated for artificial recharge will improve the quality of injected water that has been successfully treated with soil aquifer treatment technology. Groundwater pumping is 200 Mm³ annually and is likely to reach 280 Mm³ in the future. This research will explore and create a database for water resource by GIS software using its tool to select and display suitable areas for ASR operation. Artificial recharge in Kuwait has used the concept of injection and recovery of water in one cycle, while here we will apply the multi-cycle concept to avoid increasing the piezometric head and clogging the porous media. The injected water will be from wastewater treatment plants with a TDS content of less 500 ppm and the TDS of recovered water in each well less than 1500 ppm. Moreover, there are criteria for selecting a domain for artificial recharge, for example, moderate transmissivity, The TDS of the aquifer should not exceed 5000 ppm, and the horizontal and vertical hydraulic gradient should be as small as possible and close to the stations suppler and demand center. The success of artificial recharge will depend on the recovery efficiency (RE) in every cycle which will increase if artificial recharge done in the correct way. The RE increases with a decrease in time between the stopping of injection and the starting of the recovery operation. Aquifer storage and recovery can play an important role as sustainability tool to resolve water resource problems, improving water quality, better than surface water storage since it minimizes construction of new infrastructure and uses that cost to initiate new desalination or waste water plants. At the end of this research we will have demonstrated the concept of the process of ASR including the volume and time for injection and recovery of water in multi-cycles and in different suitable sites. / text

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