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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
141

Geochemistry of Ground Water - Surface Water Interactions and Metals Loading Rates in the North Fork of the American Fork River, Utah, from an Abandoned Silver/Lead Mine

Burk, Neil I 01 May 2004 (has links)
The aqueous geochemistry and hydrology of the North Fork of the American Fork River, its tributaries, and the ground water in the vicinity of the Pacific Mine site were investigated in order to determine what impact ground water entering the North Fork has on toxic metal loads in the river. Toxic metal contamination in the North Fork is great enough that brown and cutthroat trout have absorbed lead, cadmium, and arsenic in their tissues at concentrations that are hazardous to human health if consumed. Ground water that flows through the mine site flows directly through the mine tailings before entering the North Fork, which produces an acidic ground water plume that has high concentrations of toxic metals. Together, the surface water discharge results and toxic metals concentrations from the surface and ground waters were used to determine toxic metals loading rates in the North Fork and its tributaries. The results suggest that the dissolved toxic metals (As, Cd, Cu, Fe, Mn, Pb, and Zn) enter the North Fork when the river is gaining water from the ground water. However, the total toxic metal load generally decreases through the reach of river adjacent to the mine site and is significantly greater than the dissolved load. Cadmium and Mn travel as dissolved species while Cu, Fe, Pb, and Zn travel as suspended solids in the North Fork and its tributaries. Arsenic seems to be associated with both the suspended solids and travel in the dissolved state. The geochemical modeling program PHREEQC and the diffuse double layer surface complexation model were used to investigate the chemistry that controls toxic metal mobility and attenuation in the surface and ground waters at the mine site. Based on PHREEQC results, the most important reaction in these waters is the precipitation of hydrous fe1Tic oxide. The toxic metals that sorb to the hydrous ferric oxide are Cu, Pb, most importantly Zn, and to a lesser degree As.
142

Integrating Surface and Sub Surface Flow Models of Different Spatial and Temporal Scales Using Potential Coupling Interfaces

Guzha, Alphonce Chenjerayi 01 December 2008 (has links)
The main objective of this research was to develop and utilize a coupled surface water groundwater model to simulate hydrological responses of watersheds. This was achieved by coupling the U.S. Geological Survey (USGS) groundwater flow model, MODFLOW, and the rainfall runoff model, TOPMODEL, in one case study and coupling MODFLOW with a networked version of TOPMODEL called TOPNET in another case study. The model coupling was achieved using the InCouple approach, which utilizes Potential Coupling Interfaces (PCIs) that are abstractions from model flow diagrams that expose only those aspects of a model relevant to coupling. Coupling the rainfall-runoff models to MODFLOW involved development of a routine relating the spatial discretization of MODFLOW to TOPMODEL and similarly MODFLOW to TOPNET and development of a feedback scheme where groundwater and surface water interact in the soil zone. The key coupling concept was replacing the wetness index-based depth-to-water table concept of TOPMODEL with the groundwater heads simulated by MODFLOW. In the MODFLOW-TOPMODEL coupling, using data for the Tenmile Creek watershed, for the period, 1968 to 1972, it was concluded that the coupled model was able to continuously simulate the stream flow. However, the coupled model under predicted stream flow and did not agree well with observations in a point wise comparison. A mean coefficient of efficiency of 0.54 was obtained between simulated and measured stream flow. Only 24% of received precipitation was observed as baseflow and this shows that there is limited interaction between surface water and groundwater in the watershed. It was demonstrated using the coupled model that the lateral flow processes and the interactions between groundwater and surface water have a major importance for the water balance. For the Big Darby watershed, for the period 1992 to 2000, the coupled model adequately predicts the stream and groundwater flow distribution in the watershed. After model calibration, simulated groundwater showed the greatest residual variance, attributed to model error and uncertainty in model parameters. Model fit efficiencies of 0.61 and 0.69 were obtained for simulating stream flow measured at two gaging stations. The overall watershed hydrologic budget also showed small mass balance errors using the coupled model. However, the study also shows the need for further research in regard to constraining the groundwater recharge parameter which links the models.
143

Hydrochemical Definition of Ground Water and Surface Water, with an Emphasis on the Origin of the Ground-Water Salinity in Southern Juab Valley, Juab County, Utah

Hadley, Heidi K. 01 May 1996 (has links)
As part of a U.S. Geological Survey study in Juab Valley in central Utah from 1991 to 1994, the chemistry of ground - and surface -water samples was determined. Total dissolved solids in the ground water of southern Juab Valley have historically been higher , in general, than ground water in other areas of Utah . Total dissolved solids for ground-water samples from this study ranged from 623 to 3,980 milligrams/liter. High-sulfate chemical data of previous studies suggested that the major source of ground-water salinity is the dissolution of gypsum (hydrous calcium sulfate ) from the Arapien Shale. Sulfur-34 to sulfur- 32 isotopic ratio data have confirmed that dissolved Arapien Shale is the major source of salinity in southern Juab Valley water. This thesis study of southern Juab Valley had four main objectives: 1) define the present chemistry of the ground and surface water; 2) qualitatively determine the mineralogy of the Middle Jurassic Arapien Shale; 3) determine the major sources of salinity; and 4) determine the main flow path in the ground-water system. Chemical data show that the water in southern Juab Valley is predominantly of a calcium-magnesium-sulfate-bicarbonate composition. X-ray diffraction determined the mineralogy of the Arapien Shale as primarily calcite and quartz. Mineralogy of the acid-insoluble residue is illite, chlorite, quartz, and a trace of feldspar. Based on chemical, isotopic, and simple salt weight percent data, dissolution of gypsum is the major source of salinity in southern Juab Valley water. Using the chemical and isotopic data as input , a mass balance computer software program (NETPATH) helped to determine that the gypsum is derived from the Arapien Shale . NETPATH and the potentiometric surface map helped to define the main ground-water flow path as southwest across southern Juab Valley, from Chicken Creek in the San Pitch Mountains on the east side of the valley toward Chick Creek Reservoir in the southwest part of the valley.
144

Groundwater and Surface-Water Interactions along Lower Medano Creek, Great Sand Dunes National Monument, Colorado

Hadlock, Gregg L. 01 May 1995 (has links)
The objectives of this investigation are as follows: 1) review the existing hydrogeologic data for the San Luis Valley, the Great Sand Dunes Monument, and Medano Creek; 2) review the surface-water data that have been collected on Medano Creek; 3) collect or review previously collected water-level data obtained in the area of lower Medano Creek and correlate them with the surface-water data; 4) conduct constant-head permeameter tests on sand samples collected near the ground surface along lower Medano Creek; 5) produce a conceptual model of lower Medano Creek; and 6) produce a numerical model of lower Medano Creek that will predict the effect that a lowering of the regional water table could have on the terminus of flow of Medano Creek. The complex hydrogeologic conditions under lower Medano Creek have been approximated with three homogeneous and anisotropic layers. A complex system of confining layers is represented by a single low-hydraulic-conductivity layer in the middle. Numerical-modeling results suggest that the location of the terminus of flow in Medano Creek will recede significantly in response to a lowering of the regional water table, possibly by as much as 21,000 feet (6,400 meters) if the regional water table is lowered 150 feet (46 meters). These results indicate the qualitative effect that a lowering of the regional water table would have on lower Medano Creek, but they cannot be considered to be precise quantitative predictions. The results should be regarded with caution due to the paucity of data available.
145

Modeling and Understanding Groundwater Contamination Caused by Cyanotoxins from Harmful Algal Blooms in Lake Erie

Abesh, Bidisha Faruque 09 August 2019 (has links)
No description available.
146

Effects of Anthropogenic Stage Fluctuations on Surface Water/Ground Water Interactions Along the Deerfield River, Massachusetts.

Fleming, Brandon J 01 January 2009 (has links) (PDF)
Understanding the connection of surface waters to ground-water systems is important when evaluating potential water resources. In the past surface waters and ground-water have been viewed as two different sources of water but more commonly now they are viewed as one connected resource (Winter et al, 1998). The nature of connection between surface and ground-waters varies depending on climatic and geologic settings, as well as anthropogenic influences such as ground-water pumping and manipulation of river flows by dams. This thesis takes advantage of daily stage changes in the Deerfield River to investigate surface water interactions with ground-water in Charlemont, MA. Two dimensional transient numerical models are constructed to simulate ground-water response to river stage changes. These models are coupled to hypothetical mass transport models to investigate mixing mechanisms of conservative solutes under varying hydraulic scenarios. These simulations support the hypothesis that daily stage fluctuations cause a pumping mechanism which drives solutes into ground-water systems adjacent to a river at rates higher then normal flow conditions, or even under certain flood conditions. Riverbed pore-water temperature responses to diurnal temperature fluctuations are measured at two sites along the Deerfield River exposed to the same daily stage changes caused by dams. Temperature and stage data are collected at two sites with differing geologic settings. These data are used to calibrate simple two dimensional models of ground-water flow and heat transport to site specific riverbed hydraulic conductivities. It is suggested that due to the differing depositional environments of the two field sites, hydraulic conductivity of riverbed materials differ, which affects the exchange flux between surface water and ground-water. Understanding the exchange between surface and ground waters under varying hydraulic and geologic conditions is vital to characterizing local water resources and determining ecosystems health.
147

How Does Hydropeaking Alter the Hydrology of a River Reach? A Combined Water Budget, Modeling, and Field Observation Study. Deerfield River, Massachusetts

Yellen, Brian C 01 January 2012 (has links) (PDF)
Hydroelectric releases on the Deerfield River in northwestern Massachusetts affect surface water-groundwater interactions there by daily reversing the head gradient between river and groundwater. Artificially elevated stage drives river water into the riparian aquifer. Water budget analysis indicates that roughly 10% of this bank-stored water is permanently lost from the river system in a 19.5 km reach, likely as a result of transpiration by bank vegetation. Field observations as well as two-dimensional modeling results show that water losses are not uniform throughout the study reach. Riparian aquifer transmissivity in river sub-reaches largely determines the magnitude of surface water-groundwater exchange as well as net water loss from the river. These newly documented dam-induced losses from river systems inform decisions by river managers and hydroelectric operators of additional tradeoffs of oscillatory dam-release river management.
148

Water Quality Protection - A Comparative Study of India and Sweden

Shreya, Shivangi January 2017 (has links)
This report is a comparative study of ground water and surface water quality protection of a developing country India and a developed country Sweden. It covers the basic water policies, laws, rules, regulations and human right to water provisions in both the countries. The main aim of this report is to compare water quality approaches in India and Sweden and find out the best possible practices in each country and assess the need & feasibility of their application in the other. It describes the present water laws in both the countries and discusses about the present scenario of ground water and surface water quality, problems in ground water and surface water and how to deal with the problems in an efficient and sustainable way. It includes role of EU Water Framework Directive (EU WFD) in water quality protection in Sweden. Some interviews with stakeholders who are working in the water sector in Sweden are also included here. The main focus of this report is to analyse comparatively the present situation of water quality protection approaches and make recommendation for improvement of water quality. It focuses on “What can a developing country like India can learn from a developed country like Sweden for water quality protection?” and “Which things Sweden can adopt from India for water quality protection?” In this study India is found in worse environmental condition than Sweden. Indian ground water and surface water is more polluted than Swedish surface and ground water. Sweden is in much better condition than India and this country has more environmental concern too. In India, the basic reason for deterioration of water quality is lack of environment friendly attitude among the public, religious activities in water, corruption, loss of traditional methods of water conservation and protection, useless and unnecessary westernisation etc. In Sweden the basic cause of water quality deterioration is eutrophication in lakes, climate change, morphological changes, presence of metals and connectivity changes due to construction works, acidification etc. Sweden is an advanced country having the foresight for environmental concerns. They are doing research for betterment of water quality. India can learn some technological advancement and proper implementation of community participation in order to establish decentralised wastewater treatment plants and beneficial production and monitoring of energy resources from wastewater. Maintenance of online database for water is also a good thing to learn from Sweden.
149

Using novel remote sensing datasets to characterize river basin scale surface water storage dynamics

Coss, Stephen Paul January 2021 (has links)
No description available.
150

Assessing Biofiltration Pretreatment for Ultrafiltration Membrane Processes

Cumming, Andrea 01 January 2015 (has links)
An engineered biological filtration (biofiltration) process treating a nutrient-enriched, low-alkalinity, organic-laden surface water downstream of conventional coagulation-clarification and upstream of an ultrafiltration (UF) membrane process was assessed for its treatment effectiveness. The impact of biofiltration pretreatment on UF membrane performance was evaluated holistically by investigating the native source water chemistry and extending the analysis into the drinking water distribution system. The biofiltration process was also compared in treatment performance to two alternative pretreatment technologies, including magnetic ion exchange (MIEX®) and granular activated carbon (GAC) adsorption. The MIEX®, GAC adsorption, and biologically active carbon (BAC) filtration pretreatments were integrated with conventional pretreatment then compared at the pilot-scale. Comparisons were based on collecting data regarding operational requirements, dissolved organic carbon (DOC) reduction, regulated disinfection byproduct (DBP) formation, and improvement on the downstream UF membrane operating performance. UF performance, as measured by the temperature corrected specific flux or mass transfer coefficient (MTC), was determined by calculating the percent MTC improvement relative to the existing conventional-UF process that served as the control. The pretreatment alternatives were further evaluated based on cost and non-cost considerations. Compared to the MIEX® and GAC pretreatment alternatives, which achieved effective DOC removal (40 and 40 percent, respectively) and MTC improvement (14 and 30 percent, respectively), the BAC pretreatment achieved the lowest overall DOC removal (5 percent) and MTC improvement (4.5 percent). While MIEX® relies on anion exchange and GAC relies on adsorption to target DOC removal, biofiltration uses microorganisms attached on the filter media to remove biodegradable DOC. Two mathematical models that establish an empirical relationship between the MTC improvement and the dimensionless alkalinity to substrate (ALK/DOC) ratio were developed. By combining the biofiltration results from the present research with findings of previous studies, an empirical relationship between the MTC improvement versus the ALK/DOC ratio was modeled using non-linear regression in Minitab®. For surface water sources, UF MTC improvement can be simulated as a quadratic or Gaussian distribution function of the gram C/gram C dimensionless ALK/DOC ratio. According to the newly developed empirical models, biofiltration performance is optimized when the alkalinity to substrate ratio is between 10 and 14. For the first time a model has thus been developed that allows for a predictive means to optimize the operation of biofiltration as a pretreatment prior to UF membrane processes treating surface water.

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