Browsing by Author "Sale, Thomas, committee member"
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Item Open Access Composition and fabric of the Kupferschiefer, Sangerhausen Basin, Germany and a comparison to the Kupferschiefer in the Lubin Mining District, Poland(Colorado State University. Libraries, 2013) Lyons, Brianna E., author; Sutton, Sally, advisor; Ridley, John, committee member; Sale, Thomas, committee memberThe Kupferschiefer, or "copper shale," is a thin carbonaceous marly shale deposited during the Late Permian within the Zechstein Basin of central Europe. A classic example of a sediment hosted stratiform copper deposit, the Kupferschiefer is mineralized with Cu and other metals of economic interest such as Pb, Zn, and Ag. The unit is overlain by the Zechstein Limestone and underlain by the Weissliegend sandstone; it is most well known in Germany and Poland. Overall, the Kupferschiefer in the Sangerhausen Basin in Germany has been less studied than its counterpart in the Lubin mining district in Poland. Some previous studies compare the Kupferschiefer from the Lubin mining district, and more rarely the Sangerhausen Basin, to other stratiform copper deposits, but few compare data from both locations. This study analyzes, compares, and contrasts geochemical, mineralogical, and petrologic data from five Sangerhausen Basin locations and four locations in the Lubin and Rudna mines of the Lubin mining district. A total of 101 samples were examined: 61 Sangerhausen samples (41 from above the Kupferschiefer-Weissliegend contact, and 20 from below the contact) and 41 Lubin mining district samples (28 from above the Kupferschiefer-Weissliegend contact, and 13 from below the contact). Of these, 62 (36 Sangerhausen and 26 Lubin mining district) were geochemically analyzed, and 65 samples were observed in thin section (35 Sangerhausen, 30 Lubin mining district). The Sangerhausen Basin Kupferschiefer exhibits textural, geochemical, and mineralization characteristics broadly similar to those of the Lubin mining district Kupferschiefer, with a few distinct differences. Sulfide mineralization, in the form of disseminated spherules, blebs, aggregates, framboids, and bedding-parallel and -perpendicular veins, is observed in both locations on macro- and microscopic scales. The most abundant sulfide in mineralized samples from both locations is chalcocite, followed by chalcopyrite. Sulfide mineralization is commonly associated with the presence of quartz and carbonate veins in Lubin mining district samples, while mineralization is rarely associated with these veins in Sangerhausen Basin samples. Fluorescence from hydrocarbons is observed in association with sulfide mineralization in some samples, and is generally more common in samples from the Sangerhausen Basin than in those from the Lubin mining district. Both locations show similar geochemical trends with stratigraphic depth, as the units transition from Weissliegend to Kupferschiefer to Zechstein Limestone. The Sangerhausen Basin Kupferschiefer exhibits P2O5 enrichment (averaging 0.26 wt.%) compared to Lubin mining district Kupferschiefer and average shale P2O5 values (averaging 0.13 wt.% and 0.16 wt.%, respectively). Copper concentrations are greater in samples from the Lubin mining district (~14 wt.% max, most samples above ~1 to 2 wt.%) compared to Sangerhausen samples (~10 wt.% max, most samples below 0.5 wt.%). The lower ~25 cm of the Kupferschiefer is enriched in ore metals (Cu, Ag, Pb, Zn, and U) in both locations, and in the Sangerhausen Basin, in middle rare earth elements (REEs) as well. This suggests that the reactions resulting from interaction between fluids migrating from the underlying Weissliegend and overlying Zechstein evaporates mostly occurred in the lower 20 cm of the Kupferschiefer. Assuming that the REEs were carried in the mineralizing fluids, the differences in REE patterns from Sangerhausen samples taken 7 and 8 cm above the basal contact of the Kupferschiefer suggest that even within a single basin the reactions resulting from fluid interaction did not occur at the same stratigraphic level at all locations. The strata-form nature of the deposit suggests large scale bedding-parallel fluid flow. On a smaller scale, the orientation of sulfide, quartz, and carbonate veins and of elongated sulfide macro-blebs suggests that the local, small-scale flow direction is preferentially bedding-parallel as well, especially in the lower 20 to 30 cm of the Kupferschiefer where the matrix is primarily composed of alternating lenses of carbon- and clay-rich pods, and carbonate-rich pods. However, the presence of bedding-perpendicular sulfide blebs and carbonate and quartz veins illustrate that flow was not exclusively bedding-parallel. The Lubin mining district probably experienced at least two pulses of fluid flow, as illustrated by the presence of veins that exhibit alternating carbonate and sulfide precipitation; similar characteristics were not observed in the Sangerhausen Basin samples. The presence of both yellow and blue fluorescence of bitumen in Sangerhausen samples, however, suggests that there were at least two pulses of hydrocarbon migration. The generally well-sorted Lubin mining district Weissliegend was more permeable than the poorly-sorted Sangerhausen Basin Weissliegend.Item Open Access Coupled continuum pipe-flow modeling of Karst groundwater flow in the Madison limestone aquifer, South Dakota(Colorado State University. Libraries, 2013) Saller, Stephen Paul, author; Ronayne, Michael, advisor; Sale, Thomas, committee member; Egenhoff, Sven, committee memberKarst carbonate aquifers are traditionally difficult to model due to extreme permeability heterogeneities and non-Darcian flow. New modeling techniques and test applications are needed to improve simulation capabilities for these complex groundwater systems. This study evaluates the coupled continuum pipe-flow framework for modeling groundwater flow in the Madison aquifer near Rapid City, South Dakota. The Madison carbonate formation is an important source of groundwater underlying Rapid City. An existing equivalent porous medium (EPM) groundwater model of the Madison aquifer was modified to include pipe networks representing conduits. In the EPM model, karstified portions of the aquifer are modeled using high hydraulic conductivity zones. This study hypothesized that the inclusion of conduits would allow for a simpler hydraulic conductivity distribution and would improve modeled fits to available data from a 10-year monitoring period. Conduit networks were iteratively fit into the model based upon available environmental and dye tracer test data that approximated major karst pathways. Transient simulation results were evaluated using observation well hydraulic heads and estimated springflow data. In a comparison to the EPM model, the new modeling results show an improved fit to the majority of observation well targets, and negligible impact to springflow data. The flow dynamics of the aquifer model were significantly altered, with the conduit networks acting as gaining or losing subsurface features, behaving as regional sinks during dry periods and flowpath heterogeneities during wet periods. The results of this study demonstrate that the coupled continuum pipe-flow modeling method is viable for use within large regional aquifer models.Item Open Access Effects of conjunctive use on streamflow at the Tamarack State Wildlife Area, northeastern Colorado(Colorado State University. Libraries, 2012) Donnelly, Erin, author; Stednick, John, advisor; Ronayne, Michael, committee member; Sale, Thomas, committee member; Kampf, Stephanie, committee memberThe Tamarack Recharge Project in northeastern Colorado is intended to augment the streamflow of the South Platte River by 10,000 acre-feet between April and September to increase aquatic habitat for four federally threatened or endangered bird and fish species in Nebraska. The project goal is to retime surface water flows by pumping unappropriated alluvial groundwater into a recharge pond where it infiltrates and returns to the river at critical low flow periods. Retimed surface water flow will help maintain critical habitat for native aquatic species by increasing streamflow without harming water rights holders. To evaluate the effects of this managed groundwater recharge on streamflow in the South Platte River, the hydrologic environment was characterized and quantified through streamflow monitoring, water table elevation mapping, and a groundwater tracer study. Stream discharge measurements were taken at 4 cross sections on the South Platte River. Two cross sections were considered upgradient of the recharge pond and two were downgradient of the recharge pond. The mean flow of the upstream cross sections was 2.64 cubic meters per second (cms) compared to 2.66 cms at the downstream cross sections, which was not a significant difference. A fluorescein tracer study was used to estimate groundwater travel times and hydraulic conductivity. Based on the arrival time of the breakthrough curve at different piezometers, the mean hydraulic conductivity was estimated to be 331 m/d. Using this value, the estimated return time to the South Platte River at 4 cross sections ranged from 92 to 534 days. Measurements of discharge and water table elevations suggesting that Tamarack Project did not produce a measureable increase in streamflow in the South Platte River during the target period are not indicative of project functionality. The annual volume of water pumped into the recharge pond was less than 1% of the annual yield of the South Platte River. While the volume of return flows did not produce measureable results in the river, data from the tracer study and in-stream vertical hydraulic gradient data indicate a gaining stream condition during the fall and a losing stream during the winter and early spring. Potential source(s) of groundwater discharging to the stream include the recharge pond and irrigation return flows and warrant further study.Item Open Access Enhancement of coupled surface / subsurface flow models in watersheds: analysis, model development, optimization, and user accessibility(Colorado State University. Libraries, 2018) Park, Seonggyu, author; Bailey, Ryan T., advisor; Grigg, Neil S., committee member; Ronayne, Michael J., committee member; Sale, Thomas, committee memberTo view the abstract, please see the full text of the document.Item Open Access Fluorescent nanosphere transport: groundwater tracing and implications for nanoparticle migration through groundwater systems(Colorado State University. Libraries, 2015) King, Charlene N., author; Sanford, William E., advisor; Li, Yan Vivian, advisor; Ronayne, Michael J., committee member; Sale, Thomas, committee memberEngineered nanoparticles (NPs) are being introduced to water supplies and many NPs have been shown to have deleterious effects on plants and animals; however, their behavior in natural substrates is not well characterized. In an effort to characterize nanoparticle migration through porous media a dual-tracer of fluorescent carbon nanospheres (CNP) and bromide (Br) were deployed through columns of porous media designed to be homogeneous, have dual-porosity, or be reactive. The CNP are hydrophilic, non-toxic, inert, and only 5 to 10 nm in diameter. Unlike other colloid tracers CNP are designed to be inexpensive, easy to identify, and not susceptible to pore throat filtering or settling making them an ideal particle tracer. The results of the homogeneous tests show that CNP and Br had identical breakthrough curves with retardation factors close to 1, confirming that CNP transport conservatively through silica sand. The results of the dual-porosity tests suggested that CNP may undergo slightly less transverse diffusion (mass transfer) into the immobile zone than the solute tracer Br. However the differences were less than expected because molecular diffusion was overwhelmed by the high pore velocities in the experiments. The results of the reactive media tests showed that in columns with surface-modified zeolite (SMZ) the CNP transported conservatively, while Br had a retardation factor 11 to 18 times higher, due to sorption. This means that the CNP can function as the conservative species used in a multiple tracer test to quantify the surface area exposure of other minerals or contaminants with a surface charge along preferential flow paths. During each of these experiments the average mass recovery for CNP was 95% indicating that there was minimal mass loss from pore throat filtering, settling, or sorption. Not only are CNP an extremely useful new tracer for groundwater systems, but they also provide insight as to how other NPs might be transported once introduced into the subsurface. NPs with surfaces that have been functionalized to be hydrophobic or preferentially sorb to a target constituent behave differently. If NPs which sorb to a particular contaminant are introduced to the subsurface it could facilitate transport of that contaminant or facilitate sorption. Similarly the rapid transport properties of hydrophilic NPs should be considered where any toxic NP is being introduced to natural systems.Item Open Access Geochemical modeling-based prediction of water-rock interaction during aquifer storage and recovery utilizing selected Colorado Front Range aquifers(Colorado State University. Libraries, 2023) Doherty, Amanda, author; Sutton, Sally, advisor; Sale, Thomas, committee member; Ronayne, Michael, committee memberThis study characterizes the Fountain Formation, Ingleside Formation, and sandstones of the Dakota Group and considers the potential of these three formations as hypothetical Aquifer Storage and Recovery (ASR) targets. Compositional data from surface rock samples, including major, minor and trace elements from bulk rock geochemical analysis and mineral identification from petrography are used to infer a generalized mineral suite to represent each of the formations of interest. Similarly, compositional analyses from domestic water well samples, including major anions and cations and selected metals, were used as generalized representations of native water from each formation of interest. Finally, compositional data from treated city water was obtained and used as a generalized representation of injection water. The generalized rock data along with the generalized native water data represent a hypothetical injection environment while the treated water composition represents a hypothetical injection water. All water and rock data were used to populate a Single Pass Mixing equilibria Model that simulated an ASR system using the USGS geochemical modeling computer program PHREEQC (PH REdox EQuilibrium). Model results include mixed solution compositions, mineral saturation indices and estimates of mineral mass precipitation during simulated injection. Results of modeling suggest there is limited geochemical water-rock interaction during ASR in the hypothetical environment in this study. Model results indicate that the mixed solution composition is controlled more by the injected solution than by reactions occurring between the injection fluid and aquifer host material. Specifically, as greater volumes of hypothetical injection water are introduced with each model step, the compositions of the resulting mixed solutions increasingly resemble those of the injected water. The model predicted the precipitation of hematite, kaolinite and quartz during injection of the hypothetical injection water. Because aluminum was below detection in the water analyses and an arbitrary value less than the detection limit was used in the model, the prediction of kaolinite precipitation is not meaningful. Further, the model was constrained to not permit mineral dissolution, limiting the applicability of the model only to the consideration of mineral precipitation. In addition, benchtop leaching experiments were performed on rock samples to provide additional information about potential water-rock interaction. Benchtop experiment results are presented, but the focus of the study is primarily on geochemical modeling results. Water analysis results presented here suggest that the formations of interest currently contain good quality water. Modeling results suggest that injection of treated water would likely not lead to volumetrically important precipitation of minerals in the formations.Item Open Access Hydrogeologic characterization of the Fountain Formation: prospective aquifer storage and recovery targets in Front Range Colorado(Colorado State University. Libraries, 2018) Collazo, Daniel, author; Sutton, Sally, advisor; Sale, Thomas, committee member; Ronayne, Michael, committee memberAquifer storage and recovery (ASR) is a method of water storage that typically involves using the same well to inject water into and recover water from an aquifer. Benefits of ASR include lower capital costs than surface storage methods, negligible losses due to evaporation or potential contamination, and a much smaller land use footprint. This method of storing water is of interest for northern Colorado because of the location of existing water supply infrastructure and bedrock aquifers along the Front Range and the need for additional water storage. A potential storage zone for ASR in northern Colorado is the Fountain Formation. The Fountain is a Pennsylvanian-Permian arkosic conglomeratic sandstone with interbedded siltstone and shale that outcrops in a narrow, north-south trending belt from southern Wyoming to central Colorado. Within the outcrop belt, the Fountain is about 500 to 4500 feet thick and dips steeply to the east. The Fountain Formation was formed from sediments shed off the Ancestral Rocky Mountains, an uplift associated with the Ouachita-Marathon Orogeny, and deposited mainly in alluvial fans and braided streams. The composition of the formation is heterogeneous with permeable facies such as coarse sandstones adjacent to impermeable facies such as mudstones. This study characterizes the hydrogeology of the Fountain Formation to assess the feasibility of the Fountain as a storage zone for ASR, and in particular in northern Colorado. Data from 1262 wells in the Fountain were collected from the Colorado Division of Water Resources AquaMap database to characterize the hydraulic properties of the formation. The data were used to calculate specific capacity for each well and plotted on maps to help identify areas of interest for ASR. Within the formation there are wells with high yields and specific capacities which suggests that the Fountain can host high yield wells suitable for ASR. Water level elevation maps were also made for selected quadrangles and provide an approximation of the water level surface within the aquifer as well as the direction of water flow. Well-cemented outcrop samples were collected and tested for permeability using an air permeameter. The samples all have relatively low permeabilities, but it is likely that the less cemented lithologies have much higher permeabilities. The heterogenous lithology of the formation is likely able to store large volumes of water while preventing the water from migrating away from an ASR well. The results of this study suggest that the Fountain Formation is a feasible target for ASR implementation.Item Open Access Hydrogeophysical investigation of unconfined aquifer drainage behavior using temporal microgravity and water level data(Colorado State University. Libraries, 2020) Sturdivant, Matthew, author; Ronayne, Michael, advisor; Sanford, William, committee member; Sale, Thomas, committee memberUnconfined aquifers are commonly characterized by an analysis of water level changes in response to groundwater pumping during an aquifer test. Traditional analytical models predict the rate and extent of water level changes based on transmissive and storage properties of the aquifer. These models commonly assume instantaneous and complete dewatering of the pore space above a falling water table, which neglects time-dependent storage changes in the unsaturated zone. By sensing pumping-induced water mass changes in both the saturated and unsaturated zones, gravity surveys provide an opportunity for improved characterization of unconfined aquifers. In this study, a time-lapse microgravimetric survey was performed during pumping from a shallow unconfined aquifer in northern Colorado. Water level data were collected at four monitoring wells located along a radial transect at 6.34, 15.4, 30.7. and 61.2 meters from the pumping well. Gravity measurements were collected adjacent to the second well at 15.4 meters. Pumping from the aquifer resulted in a water level decline ranging from 0.35 meters at the distant well to 1.5 meters at the closest well. A total of 3.89 ∙ 106 kg of water mass was pumped during the test, resulting in a decline in gravitational acceleration of 27.2 microGals at the fixed measurement location. The gravity data are not adequately explained by traditional analytical models that predict negligible mass changes as the water table beings to stabilize. This highlights potential inaccuracies in drawdown model assumptions that are not readily discernible with water level data alone.Item Open Access Hydrologic characterization of upper Permian-Cenozoic sedimentary strata of Larimer County: prospective aquifer storage and recovery targets(Colorado State University. Libraries, 2017) Adam, Adam, author; Sutton, Sally, advisor; Sanford, William, committee member; Sale, Thomas, committee memberProviding adequate water storage is an on-going problem along the northern Colorado Front Range. This study compiles existing hydrogeological data from water wells to identify potential ASR sites in eastern Larimer County, Colorado. These water well data are used to evaluate both geographic localities and individual lithologic units. All stratigraphic units younger than the Pennsylvanian-Permian Fountain Formation and reported to host water wells in eastern Larimer County are considered here. A total of 1094 AquaMap water well reports have been mined for data, including depth, pumping level, static water level, lithology, location, date drilled, and yield. Additionally, specific capacity has been calculated for each well. The data points were plotted using ArcGIS and geological maps from US Geological Survey as base maps. The main parameters considered are water well yields and specific capacities. Yield is an indication of the ability of an aquifer to permit movement of water, but the yield data available may not reflect the maximum ability of a well to produce or store water. This is because water is pumped out according to the usage or purpose of the well, with irrigation and livestock wells typically yielding more than household wells. In some locations the aquifers considered can likely produce more than indicated by reported yields. Based on both hydrogeological properties and widespread occurrence in the study area the Pierre Shale Formation, the Lytle Formation, and the Ingleside Formation appear to show the greatest promise as ASR targets. Additional units that could be worth further consideration include the Jelm and Lykins Formations. Based solely on hydrogeological data, the White River, Laramie, and Fox Hills Formations would be the strongest candidates for ASR, but are geographically limited to the far northeast corner of the county. In addition, well data from unconsolidated alluvial deposits suggest strong potential for ASR, especially near the eastern edge of the County, but the combination of very high permeability and surface exposure would make ASR in these deposits challenging because of difficulty maintaining control of stored water. Based on well data, there are some specific localities that may merit further consideration for ASR, including the vicinity of Laporte, where several stratigraphic units host wells with high yields and high specific capacities. Similarly, there are wells in several stratigraphic units, including the Pierre Shale Formation, CarlileGraneros-Mowry Shales, Owl Canyon Formation, Lyons Formation, and Lytle Formation, in an area to the west of Loveland that show promise for ASR. Additionally, the Pierre Shale Formation hosts several clusters of wells indicating strong potential for ASR; the best developed of these clusters are in the northern third of the Larimer County, specifically northwest of Wellington.Item Open Access Influence of subsurface heterogeneity on the performance of aquifer storage and recovery in the Denver Basin(Colorado State University. Libraries, 2016) Cannan, Catharine, author; Ronayne, Michael, advisor; Sale, Thomas, committee member; Sanford, William, committee memberAquifer storage and recovery (ASR) is a process through which water is injected into an aquifer for storage and recovered for later use. As water demand worldwide increases there is a growing need to evaluate alternative approaches to water storage, including ASR. Increasing our understanding of the fate of injected water and the subsurface conditions in which ASR is being performed can guide operational choices and decisions on the feasibility of ASR in new regions. Previous evaluations of ASR performance have often assumed homogeneity in the subsurface, overlooking the existence of preferential flow paths created by the combination of transmissive and non-transmissive inter-beds. Because these pathways can influence the lateral transport of water away from injection wells, ASR performance may be impacted. In this study a groundwater flow model within the Denver Basin, Colorado were used to evaluate ASR performance in a heterogeneous subsurface environment. Geologic data in the vicinity of Highlands Ranch, Colorado were synthesized to create heterogeneous, three-dimensional aquifer analogs using multiple-point geostatistical simulation. Flow simulation for these aquifer models was performed to evaluate ASR cycles comprised of injection, storage, and extraction phases, and results were compared to a homogeneous aquifer model. Three metrics were used to assess ASR performance: the extent of hydraulic head changes in the aquifer, fate of injected water particles, and recovery efficiency. Results show that the travel distance of injected water particles was influenced by the presence of heterogeneity and that preferential pathways increase both the variability and maximum distance traveled by injected water particles. Predicted recovery efficiency decreased slightly when heterogeneity was incorporated, while head change extent was far less sensitive to the presence of heterogeneous structures. These results demonstrate not only the influence of aquifer heterogeneity on ASR performance, but also the potential for geostatistical analysis and numerical modeling to be used as tools for planning future ASR operations.Item Open Access Methodologies to detect leakages from geological carbon storage sites(Colorado State University. Libraries, 2014) González-Nicolás Álvarez, Ana, author; Baù, Domenico, advisor; Fontane, Darrell, committee member; Ronayne, Michael, committee member; Sale, Thomas, committee memberGeological carbon storage (GCS) has been proposed as a favorable technology to reduce carbon dioxide (CO2) emissions to the atmosphere. Candidate storage formations include abandoned oil and natural gas reservoirs, un-mineable coal seams, and deep saline aquifers. The large global storage capacity and widespread occurrence of deep saline formations make them ideal repositories of large volumes of CO2, however they generally lack of data for geological characterization in comparison to oil and gas reservoirs. Thus, properties of the injected formation or the sealing formation are unknown, which implies that the evolution and movement of the CO2 plume are uncertain in these geological formations. The first part of this research aims to provide an understanding of the main sources of uncertainty during the injection of CO2 that cause leakage variability and fluid pressure change near the injection well, which could be responsible for fracturing the sealing formation. With this purpose the effect of uncertain parameters such as permeability and porosity of injected aquifer, permeability of CO2 leakage pathways through the sealing layers, system compressibility, and brine residual saturation are investigated using stochastic and global sensitivity analyses. These analyses are applied to a potential candidate site for GCS located at the Michigan Basin. Results show aquifer permeability and system compressibility are the most influential parameters on fluid overpressure and CO2 mass leakage. Other parameters, such as rock porosity, permeability of passive wells, and brine residual saturation do not influence fluid overpressure nearby the injection well. CO2 mass leakage is found to be sensitive to passive well permeability as well as the type of statistical distribution applied to describe well permeability. Scarce data of the Michigan Basin exist that can be used directly to describe the spatial distribution at the basin scale of the caprock overlying the candidate site. The continuity of this formation is uncertain. The second part of this investigation explores the application of binary permeability fields for the study of CO2 leakage from GCS at the candidate site. A sequential indicator simulation algorithm is used to populate binary permeability fields representing a caprock formation with potential leaky areas (or inclusions). Results of the caprock continuity uncertainty conclude that increasing the probability of inclusions occurrence increases the CO2 leakage. In addition, the correlation length used by the sequential indicator simulator affects the occurrence of inclusions. The third part investigates the detection and location of the presence of possible brine or carbon leakage pathways at the caprock during the injection operations of a GCS system. A computational framework for the assimilation of changes in head pressure data into a subsurface flow model is created to study the evolution of the CO2 plume and brine movement. The capabilities of two data assimilation algorithms, the ensemble smoother (ES) and the ensemble Kalman smoother (EnKS), to identify and locate the leaky pathways are examined. Results suggest that the EnKS is more effective than the ES in characterizing caprock discontinuities.Item Open Access Modeling artificial groundwater recharge and low-head hydroelectric production: a case study of southern Pakistan(Colorado State University. Libraries, 2016) Siddiqui, Rafey Ahmed, author; Bailey, Ryan T., advisor; Grigg, Neil S., committee member; Sale, Thomas, committee member; Sanford, William, committee memberDHA City Karachi (DCK), a city designed for approximately one million people, is envisaged to become a satellite city to the second largest city in the world, Karachi, which has a population of 25 million. The upcoming city is located 21 miles north of main metropolitan Karachi in the arid southern part of Pakistan. The region receives little rainfall with an annual average of 217 mm and temperatures ranging from an average of 88°F in the summers to 68°F in the winters. The town has a projected water demand in the fully developed stage of 45 Million Gallons per Day (MGD) and 500 Mega Watts (MW) of electricity. Since water and electricity are prized and expensive commodities in the region, alternate and renewable sources of both need to be explored for DCK to meet its goal of sustainability and conservation. Two options for these sources, artificial recharge and hydroelectric product, are explored in this study. Artificial recharge to replenish groundwater resources is becoming more common in arid areas. In this thesis, the capacity of small lakes to produce significant seepage and recharge to the underlying aquifer within city limits is explored for DCK. The lakes are fed by treated effluent from Sewage Treatment Plants (STP), which then ponds and creates downward seepage to the water table. Artificial recharge and resulting groundwater flow within the aquifer is simulated using a three-dimensional groundwater flow model (MODFLOW). A variety of pumping scenarios are explored to determine the quantity of groundwater that can be pumped for water supply. An optimal placement of 50 pumps throughout the city also is determined, with drawdown used as the variable to be minimized so as to minimize pumping costs. In the fully developed stage of artificial recharge, the lakes feed almost 7.9 MGD of water to the aquifer, out of which 6.6 MGD can be pumped out and consumed sustainably on a daily basis through the 50 planned wells. Since DCK is to be developed and inhabited in 3 phases, analysis revealed that quantities of 1.4 and 3.5 MGD can be pumped out sustainably for the short and mid-term developmental plans. A sustainable hydroelectric system was also designed for using the hydraulic structures of the small lakes. System control was introduced by application of Artificial Neural Networks (ANN) and Model Predictive Control (MPC) to maintain the hydroelectric potential and constant head against variation in flow as delivered from the STPs. The results show an output of 13.92 MW of green and sustainable hydroelectricity which can be produced at a very low cost. A cost-benefit analysis projects a savings of $11,550 and $60,000 per day due to the artificial groundwater recharge and hydroelectric production respectively, with the cost of construction of these projects being paid off within 5 and 2 years at this rate, including the cost of operation and maintenance. Results, however, should be used with caution due to the preliminary nature of the models and calculations.Item Open Access Paleo-fluid migration and diagenesis in the Pennsylvanian-Permian Fountain Formation(Colorado State University. Libraries, 2013) Hogan, Ian, author; Sutton, Sally, advisor; Ridley, John, committee member; Sale, Thomas, committee memberThe Pennsylvanian-Permian Fountain Formation is an arkosic conglomeratic sandstone that was deposited in fluvial environments along the eastern flanks of the ancestral Rocky Mountains. The formation owes its pinkish red color to hematite cement that was precipitated early in its diagenetic history. Within the formation are whitened strata that crosscut laminations and facies boundaries, indicating that they are the result of a post depositional process. Whitened features are seen in core, indicating that they are not caused by modern weathering processes. Whitened strata similar to those present in the Fountain Formation are usually the result of the migration of reducing fluids. These fluids reduce and remove hematite cement leaving the fluid migration pathways whitened. Fluids that can cause large-scale reduction and removal of iron oxides include basinal aqueous brines and hydrocarbons. Whitening within the Fountain Formation appears in a predictable stratigraphically-controlled manner and is most common in coarse channel sandstone facies that are adjacent to laterally continuous paleosol mudstones. The predictable distribution of whitened strata in outcrop suggests that fluid followed preferential pathways. Outcrop analysis indicates that these pathways are closely associated with thin paleosol mudstones and overbank deposits that seem to have focused the paleo-fluids that then flowed laterally along them in the coarser channel sandstones. Laterally continuous paleosol mudstones therefore may have played an important role in determining the spatial location of paleo-fluid migration pathways. Fluids moved through the formation as stringers that took up less than 15% of the total rock volume. The Fountain Formation has a complex diagenetic history and has undergone multiple stages of cementation. A late stage dolomite cement contains organic matter, hydrocarbon inclusions, and is associated with bitumen. This cement is restricted to whitened strata and likely precipitated from a hydrocarbon-bearing fluid. The hydrocarbon-bearing fluid may have been the fluid that was responsible for whitening sections of the Fountain. Fluid inclusion data indicate that the precipitation of this cement took place after the formation was buried to a depth of at least 1.3km, which would have been during or after Laramide deformation. The presence of bitumen and hydrocarbon inclusions in strata that were not buried to hydrocarbon generating depths indicates that the hydrocarbon-bearing fluid likely migrated through the formation from deeper in the basin. The amount of whitening in outcrop decreases in the northern study sites and may be related to a decrease in coarse channel sandstone facies. The lesser abundance of those facies at northern study sites may be because those sites were further from the sources for coarse material and were associated with lower energy environments. Although there is less whitened rock at the northern sites, the amount of fluid that passed through them may have been similar to the amount of fluid that passed through the southern sites. Evidence of this is a higher amount of feldspar alteration in whitened strata in the northern site, which may have been caused by more fluid flow per volume of rock because there were fewer coarse channel facies to act as conduits.Item Open Access The fresh groundwater lenses in the Arabian Peninsula: formative, stability and management assessments(Colorado State University. Libraries, 2019) Alrashidi, Mosaed, author; Bailey, Ryan, advisor; Grigg, Neil, committee member; Sale, Thomas, committee member; Sanford, William, committee memberThe formation of fresh groundwater lenses (FGLs) overlying denser, saline or brackish groundwater is a fascinating hydrologic phenomenon that creates groundwater supplies of great potential value for humans and ecosystems in several formation settings, such as coastal areas, atoll islands, riverine floodplains, and subterranean oases in arid regions. In particular, FGLs in subterranean oases are a critical source of freshwater supply in arid regions, due to a general lack of perennial rivers and lakes. These FGLs are in danger of salinization due to natural events and anthropogenic stresses. Although extensive research has been conducted on FGLs in general, the FGLs in subterranean oases in arid regions have received less attention. Key knowledge gaps include the quantity and frequency of natural recharge to these FGLs; reliable estimates of environmental aquifer dispersivity at the scale of subterranean FGLs; the timing of lens development; and the impact of anthropogenic activities on lens dynamics. This dissertation focuses on the FGLs of subterranean oases in the Arabian Peninsula (AP), using the Rawdatain FGL in Kuwait as a case study. Among the FGLs in the AP, the Rawdatain FGL in Kuwait is perhaps a unique candidate because of its size and the availability of extensive subsurface data for the pre-development period. The main objectives of this study are as follows: (1) estimate long-term average annual recharge for the Rawdatain FGL and investigate the timing of lens depletion due to climate change; (2) provide a realistic range of longitudinal (αL), horizontal transverse (αh), and vertical transverse (αv) dispersivity values for the aquifer; and (3) assess the impacts of historical and future anthropogenic activities and evaluate artificial recharge alternatives for lens recovery storage (LSR). In this study, a 3D density-dependent groundwater flow and solute transport model using the SEAWAT modeling code is developed using the following pre-development period calibration targets: (1) groundwater head, (2) spatially-variable total dissolved solids (TDS) groundwater concentration, (3-5) three groundwater volume targets, (6-8) three vertical thickness targets of stored groundwater of three different water quality TDS ranges (0−700, 700−1000, and 1000−2000 mg/L), and (9) geometrical shape features of the lens along cross-sections. In addition, groundwater age data of the Rawdatain FGL was used as an independent factor to constrain the dispersivity and recharge rate during the simulated period of lens development. Moreover, a sensitivity analysis was performed to explore the effects of the hydraulic conductivity, boundary conditions, and vertical transverse dispersivity on lens geometry. Based on a comparison of twelve annual recharge amount scenarios using a constant recharge mechanism (CRM) (R1 to R12: 0.2 to 5.0 million m³/year) with data targets, the R5 (0.5 million m³/year) recharge scenario is selected to represent the long-term average annual recharge. These results demonstrated that the annual natural replenishment of the Rawdatain FGL is minimal compared with its size. A macro-scale stability assessment shows that a 50% reduction in annual recharge within a 100-year time frame would reduce the lens volumes by 21%, 17% and 9% for the three water quality categories. A multi-criteria score-based method was performed to rank the best performance of 28 dispersivity sets (D1 to D28: 1 to 500 m) among all of the targets with an equal weight, on a scale of 0 to 300 x 106 m3. The results illustrated that the D16 dispersivity set (αL = 50 m: αh = 5 m: αv = 0.1 m) represents the best large-scale environmental dispersivity values for the Rawdatain FGL and can be used for analyzing the natural mixing between the ambient brackish water and fresh water. A new baseline model for the predevelopment period using a pulse recharge mechanism (PRM) was established to assess the recharge frequency along with the longitudinal dispersivity. The results revealed that the 50 m longitudinal dispersivity set and one pulse recharge every two years had the best performance, and they were selected to simulate the effects of the infrequent rainfall events and anthropogenic impacts simultaneously. During the groundwater abstraction from 1963 to 2018, the reduction in the stored volumes was 28%, 17% and 12% for the three quality categories. The future pumping scenarios (2019-2100) suggested that the 0.16×106 m3/year is a suitable alternative for long-term use, 0.5×106 m³/year)is an appropriate option for short-term use, and extraction scenarios greater than 1.0×106 m³/year will cause a remarkable degeneration of the Rawdatain FGL. Artificial recharge scenarios (2019-2028) imply that a successful LSR for the Rawdatain FGL depends on selecting appropriate well locations and amounts of injected water. For instance, the I2 alternative could achieve a 100% storage recovery within 7.5, 8 and 9 years for the three water quality categories. This study provides a first attempt to model the formation of a FGL, assess the historical anthropogenic stresses, and evaluate future management scenarios in subterranean oases in arid regions. Implementing multiple data targets and water age is a unique process of calibration that was helpful in eliminating several non-unique calibration parameters and in decreasing the uncertainty of the calibrated parameters. The methodology presented herein provides a general approach that can be extrapolated to other FGLs with similar climatic and environmental circumstances. The outputs of this dissertation enhance the understanding of the formation, stability, and management of these lenses and will be very valuable to water managers for establishing appropriate water supply plans for these valuable water reserves, leading to preferable future water security in the AP.Item Open Access The sustainability of atoll islands freshwater lenses under non-stationary climatic and anthropogenic stresses(Colorado State University. Libraries, 2017) Alsumaiei, Abdullah Ahmad, author; Bailey, Ryan, advisor; Grigg, Neil, committee member; Ronayne, Michael, committee member; Sale, Thomas, committee memberTo view the abstract, please see the full text of the document.Item Open Access Using RMS amplitudes from forward seismic-reflectivity modeling of channelized deep-water slope deposits to inform stratigraphic interpretation and sub-seismic scale architecture, Tres Pasos Formation, Magallanes Basin, Patagonia, Chile(Colorado State University. Libraries, 2018) Nielson, Adam, author; Stright, Lisa, advisor; Schutt, Derek, committee member; Sale, Thomas, committee memberDeep-water slope channels outcropping in the Tres Pasos Formation of the Magallanes Basin in southern Chile are used as the foundation of a forward seismic-reflectivity modeling study to better inform stratigraphic interpretation. The multi-scale architecture of deep-water slope channels is often difficult to interpret from low resolution seismic-reflectivity surveys. Valuable insight can be gained from forward seismic-reflectivity modeling using multiple-scales of architecture as building blocks (i.e., channel elements stacking into channel complexes) to provide insight into subsurface interpretation. Forward seismic-reflectivity models of channel elements with sub-meter scale heterogeneity are interrogated for RMS amplitude and apparent thickness as a function of true stratigraphic thickness and net sand thickness. Relationships between interpreted variables from the forward models (RMS amplitude and apparent thickness) compared to measured variable from the input models (true stratigraphic thickness and net sand thickness) provide recognition criteria for interpreting building blocks in subsurface seismic-reflectivity data. This study shows that decreasing RMS amplitude for constant apparent thickness is primarily controlled by vertically juxtaposed facies between multiple stacked channel elements. Furthermore, laterally stepping and vertically aggrading channel elements increase confidence in stratigraphic interpretation whereas laterally migrating channel elements are harder to delineate. An increase in frequency tends to improve interpretation of net sand thickness for multiple channel elements informing interpretation of lateral facies changes. Results from this study also show that RMS amplitudes and apparent thickness show patterns to help differentiate channel element stacking configurations and can be tied back to the known model variables, true stratigraphic thickness and net sand thickness. However, interpretation of exploration scale data, specifically RMS amplitude and apparent thickness interpretations is complicated by interfering reflections at increased frequency, complicating the recognition of multiple channel elements within a channel complex set.