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Dissertations / Theses on the topic 'Stream and groundwater salinity'

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Published: 10 December 2022
Last updated: 28 January 2023

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1

Buck, Christina Rene. "Managing Groundwater for Environmental Stream Temperature." Thesis, University of California, Davis, 2013. http://pqdtopen.proquest.com/#viewpdf?dispub=3565483.

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This research explores the benefits of conjunctively managed surface and groundwater resources in a volcanic aquifer system to reduce stream temperatures while valuing agricultural deliveries. The example problem involves advancing the understanding of flows, stream temperature, and groundwater dynamics in the Shasta Valley of Northern California. Three levels of interaction are explored from field data, to regional simulation, to regional management optimization. Stream temperature processes are explored using Distributed Temperature Sensing (DTS) data from the Shasta River and recalibrating an existing physically-based flow and temperature model of the Shasta River. DTS technology can collect abundant high resolution river temperature data over space and time to improve development and performance of modeled river temperatures. These data also identify and quantify thermal variability of micro-habitat that temperature modeling and standard temperature sampling do not capture. This helps bracket uncertainty of daily temperature variation in reaches, pools, side channels, and from cool or warm surface or subsurface inflows. The application highlights the influence of air temperature on stream temperatures, and indicates that physically-based numerical temperature models, using a heat balance approach as opposed to statistical models, may under-represent this important stream temperature driver. The utility of DTS to improve model performance and detailed evaluation of hydrologic processes is demonstrated.

Second, development and calibration of a numerical groundwater model of the Pluto's Cave basalt aquifer and Parks Creek valley area in the eastern portion of Shasta Valley helps quantify and organize the current conceptual model of this Cascade fracture flow dominated aquifer. Model development provides insight on system dynamics, helps identify important and influential components of the system, and highlights additional data needs. The objective of this model development is to reasonably represent regional groundwater flow and to explore the connection between Mount Shasta recharge, pumping, and Big Springs flow. The model organizes and incorporates available data from a wide variety of sources and presents approaches to quantify the major flow paths and fluxes. Major water balance components are estimated for 2008-2011. Sensitivity analysis assesses the degree to which uncertainty in boundary flow affects model results, particularly spring flow.

Finally, this work uses optimization to explore coordinated hourly surface and groundwater operations to benefit Shasta River stream temperatures upstream of its confluence with Parks Creek. The management strategy coordinates reservoir releases and diversions to irrigated pasture adjacent to the river and it supplements river flows with pumped cool groundwater from a nearby well. A basic problem formulation is presented with results, sensitivity analysis, and insights. The problem is also formulated for the Shasta River application. Optimized results for a week in July suggest daily maximum and minimum stream temperatures can be reduced with strategic operation of the water supply portfolio. These temperature benefits nevertheless have significant costs from reduced irrigation diversions. Increased irrigation efficiency would reduce warm tail water discharges to the river instead of reducing diversions. With increased efficiency, diversions increase and shortage costs decrease. Tradeoffs and sensitivity of model inputs are explored and results discussed.

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2

Dale, Ryan. "Salinity, temperature, and macroinfaunal communities in groundwater seeps." Access to citation, abstract and download form provided by ProQuest Information and Learning Company; downloadable PDF file 9.34 Mb., p, 2006. http://gateway.proquest.com/openurl?url_ver=Z39.88-2004&res_dat=xri:pqdiss&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&rft_dat=xri:pqdiss:1435921.

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3

Chapman, Ryan William. "Urban groundwater, stream conditions, and homeowner perceptions." [Ames, Iowa : Iowa State University], 2008.

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4

Khater, A. M. R. "Management of stream-aquifer systems." Thesis, University of Southampton, 1988. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.380176.

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5

Lund, David Charles. "Gulf Stream temperature, salinity and transport during the last millennium /." Cambridge, Mass. : Woods Hole, Mass. : Massachusetts Institute of Technology ; Woods Hole Oceanographic Institution, 2006. http://hdl.handle.net/1912/1774.

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Originally issued as the author's thesis (Ph. D.)--Massachusetts Institute of Technology and Woods Hole Oceanographic Institution, 2006.
"February 2006". "Doctoral dissertation." "Department of origin: Geology and Geophysics." "Joint Program in Oceanography/Applied Ocean Science and Engineering"--Cover. Includes bibliographical references.
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6

Lund, David Charles. "Gulf stream temperature, salinity and transport during the last millennium." Thesis, Massachusetts Institute of Technology, 2005. http://hdl.handle.net/1721.1/34567.

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Thesis (Ph. D.)--Joint Program in Oceanography (Massachusetts Institute of Technology, Dept. of Earth, Atmospheric, and Planetary Sciences; and the Woods Hole Oceanographic Institution), February 2006.
Includes bibliographical references.
Benthic and planktonic foraminiferal [delta]18O ([delta 18Oc) from a suite of well-dated, high-resolution cores spanning the depth and width of the Straits of Florida reveal significant changes in Gulf Stream cross-current density gradient during the last millennium. These data imply that Gulf Stream transport during the Little Ice Age (LIA: 1200-1850 A.D.) was 2-3 Sv lower than today. The timing of reduced flow is consistent with cold conditions in Northern Hemisphere paleoclimate archives, implicating Gulf Stream heat transport in centennial-scale climate variability of the last 1,000 years. The pattern of flow anomalies with depth suggests reduced LIA transport was due to weaker subtropical gyre wind stress curl. The oxygen isotopic composition of Florida Current surface water ([delta]18Ow) near Dry Tortugas increased 0.4%0/ during the course of the Little Ice Age (LIA: -1200-1850 A.D.), equivalent to a salinity increase of 0.8-1.5 psu. On the Great Bahama Bank, where surface waters are influenced by the North Atlantic subtropical gyre, [delta]18Ow increased by 0.3%o during the last 200 years. Although a portion (-O. 1%o) of this shift may be an artifact of anthropogenically-driven changes in surface water [Epsilon]CO2, the remaining [delta]18Ow signal implies a 0.4 to 1 psu increase in salinity after 200 yr BP.
(cont.) The simplest explanation of the [delta]18Ow, data is southward migration of the Atlantic Hadley circulation during the LIA. Scaling of the [delta]18Ow records to salinity using the modern low-latitude 180,w-S slope produces an unrealistic reversal in the salinity gradient between the two sites. Only if [delta]18Ow is scaled to salinity using a high-latitude [delta]18Ow-S slope can the records be reconciled. Changes in atmospheric 14C paralleled shifts in Dry Tortugas [delta]18Ow, suggesting that variable solar irradiance paced centennial-scale Hadley cell migration and changes in Florida Current salinity during the last millennium.
by David C. Lund.
Ph.D.
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7

Pritchard, Jodie Lee, and jodie_pritchard@hotmail com. "Dynamics of stream and groundwater exchange using environmental tracers." Flinders University. School of Chemistry, Physical & Earth Science, 2006. http://catalogue.flinders.edu.au./local/adt/public/adt-SFU20060407.122526.

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Regions of surface water and groundwater exchange are major sites for the transfer and transformation of solutes and nutrients between stream and subsurface environments. Conventional stream and groundwater exchange investigations are limited by methodologies that require intensive field investigations and/or the set-up of expensive infrastructure. These difficulties are exacerbated where hydraulic gradients are very low and stream discharge highly variable. This thesis uses a suite of environmental tracers (Cl-, Rn-222, H-2 & O-18, Sr-87/Sr-86) to characterise the extent of stream and groundwater exchange between a sand bed stream and adjacent alluvial aquifer in a subtropical catchment (the Wollombi Brook) of eastern Australia. The aims were to identify sources and relative contributions of different sources of groundwater to stream discharge and specifically to improve the methodology of using Rn-222 to obtain quantitative estimate of groundwater fluxes. The sensitivity of the Rn-222 technique for identifying groundwater discharge based on the Rn-222 concentration in stream water was improved via an iterative numerical approach to account for Rn-222 loss from stream water via turbulent gas exchange and radioactive decay. Optimal distances between stream sampling points for defining the magnitude of groundwater discharge to stream flow based on Rn-222 concentrations in stream water is a function of average stream velocity and water depth. The maximum allowable distance between sampling points for determining the magnitude of groundwater discharge to the Wollombi Brook was 2 km. This work showed that groundwater discharged to all reaches of the Wollombi Brook during baseflow and flood recession conditions. Alluvial groundwater contributed less than 30% of water to stream flow in the mid Wollombi Brook catchment. Dilution of steady-state Rn-222 concentrations measured in transects from the stream to the alluvial sediments showed that significant surface water and groundwater exchange occurs even when gradients between surface water and groundwater are low. Lateral stream water influx to the adjacent alluvial aquifer was more extensive in the lowland areas of the Wollombi Catchment during low flow than flood recession conditions. Extensive stream water influx to the adjacent alluvial aquifer occurs contrary to the net direction of surface water and groundwater flux (as indicated by hydraulic gradients toward the stream channel). The rate of stream and groundwater exchange within the adjacent alluvial aquifer appears to be greatest during baseflow conditions. Fresh alluvial groundwater appeared to provide a buffer against higher salinity regional groundwater discharge to the alluvial aquifer in some reaches of the Wollombi Brook catchment. Pumping of the alluvial aquifer and diversions of surface water may jeopardise the water quality and volume of the alluvial aquifer and induce water flow from the regional aquifer toward the stream, potentially salinising the fresh alluvial aquifer and subsequently the stream. The change in the Cl- concentration and the variation in slope of the deuterium � oxygen-18 line between consecutive stream sampling points could be used to differentiate between regional and alluvial groundwater discharge to stream flow. Incorporating this information with three-component end-member mixing using [Sr2+] and Sr-87/Sr-86 showed that stream and alluvial groundwater exchange within the stream channel was highest in the lowland floodplains during low flow conditions. The least stream and alluvial groundwater exchange occurred in the low streambed gradient mid reaches of the Wollombi Brook regardless of stream stage. The greatest difference in the degree of stream and alluvial groundwater exchange between high and low stream stages occurred in the lowland floodplains of the Wollombi Brook.
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8

Lewis, Marjorie Fay. "The significance of episodic recharge in the Wheatbelt of Western Australia /." Connect to thesis, 2000. http://eprints.unimelb.edu.au/archive/00000682.

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9

Kriyo, Sambodho. "The Dynamics of Groundwater Flow and Salinity Transport in Unconfined Coastal Aquifers." 京都大学 (Kyoto University), 2010. http://hdl.handle.net/2433/97967.

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10

Mallakpour, Iman E. "Accounting for Stream Bank Storage for a Seasonal Groundwater Model." Thesis, The University of Arizona, 2011. http://hdl.handle.net/10150/203502.

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In recent research on groundwater and surfacewater interaction, attention has focused on the study of water exchanges between the near-stream aquifer and stream. One of the important near stream processes is bank storage. The aim of this thesis is to document the procedure required to develop a bank storage model that can be linked into a MODFLOW groundwater model. For this purpose, a groundwater model and a MATLAB code that can simulate bank storage process was developed. These two models were linked through the well package of MODFLOW. Result indicated that the number of stage rise and shape of stage hydrograph entering to stream system, when they have the same average stream stage, produced similar net flux of water between surface water and groundwater. In addition, the results show that reaches, which were gaining during normal flow of the stream network, can become a losing stream during high flow periods.
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11

Nippert, Howard Christian. "Investigation of salinity and nutrient characteristics of two groundwater based flow systems on Virginia's Eastern Shore." Thesis, This resource online, 1993. http://scholar.lib.vt.edu/theses/available/etd-11242009-020234/.

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12

Purczel, Carl Leslie. "Evaluating and applying contaminant transport models to groundwater systems /." Title page, contents and abstract only, 2001. http://web4.library.adelaide.edu.au/theses/09SM/09smp9854.pdf.

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13

Ghamarnia, Houshang. "Effects of salinity on water extraction by roots under shallow groundwater table conditions." Thesis, University of Newcastle Upon Tyne, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.364808.

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14

Grant, Jane D. "The significance of groundwater-surface water interactions on hyporheic physico-chemistry and stream ecology in two Scottish mountain rivers." Thesis, Available from the University of Aberdeen Library and Historic Collections Digital Resources. Online version available for University members only until Apr. 7, 2010, 2008. http://digitool.abdn.ac.uk:80/webclient/DeliveryManager?application=DIGITOOL-3&owner=resourcediscovery&custom_att_2=simple_viewer&pid=26046.

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15

Maida, Susan Marie 1959. "The value of iodide as a geochemical indicator of sources of salinity in groundwater." Thesis, The University of Arizona, 1989. http://hdl.handle.net/10150/277039.

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Iodine, a minor constituent in ground water, is valuable as an indicator of subsurface sources of salinity. A review of iodine geochemistry reveals that exceptions to conservative behavior include sorption onto iron and aluminum oxides and incorporation into marine organic matter with additional enrichment due to sorption. Data from the Milk River aquifer in Alberta, Canada indicate that iodide in the ground water is derived from residual waters in the fine grained, marine sediments within the sandstone formation. This localized enrichment of iodide is superimposed on a more general enrichment of halides downgradient from the recharge area, probably due to ion filtration.
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16

Covino, Timothy Patrick. "Stream-groundwater interactions in a mountain to valley transition: impacts on watershed hydrologic response and stream water chemistry." Thesis, Montana State University, 2005. http://etd.lib.montana.edu/etd/2005/covino/CovinoT1205.pdf.

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As mountain headwater catchments increase in size to the meso-scale, they incorporate new landscape elements including mountain-valley transition zones. Mountain-valley transition zones form part of the mountain front, influence groundwater (GW)-stream interactions, and impact hydrologic response and stream water composition. Mountain front recharge (MFR) in mountain-valley transition zones and subsequent GW discharge to streams in the valley bottom are important hydrological processes. These GW-stream interactions are dynamic in both space and time, playing a key role in regulating the amount, timing, and chemistry of stream water reaching the valley bottom. I hypothesize that mountain-valley transitions function as hydrologic and biogeochemical buffers via GW recharge and subsequent GW discharge. More specifically, that streams often recharge GW near the mountain front and receive stored GW further downstream. To investigate these processes I applied physical hydrology techniques, and geochemical hydrograph separations in the Humphrey Creek watershed in southwestern Montana. This allowed me to assess the spatial and temporal variability of mountain front GW recharge and GW-stream interactions across a mountain-valley transition. Geochemical signatures were used to partition stream flow into alpine runoff and GW sources. These results indicate that much of the alpine stream water recharged GW at the mountain front and that stored GW of a different chemical composition sustained down-valley stream discharge. Down-valley stream discharge was dominated by GW inputs and responded to GW stage more closely than upstream reaches. A critical GW stage height was necessary for down-valley channel flow, as this was the only major input to channel flow during early and late season base flow. Conversely, GW contributed little to stream flow in the upper reaches of the study area. GW-stream water exchange served as a flow and geochemical buffer, resulting in significant changes in stream chemistry from the alpine, to the MFR zone, to the valley bottom and muting fluctuations in channel flow, both at high and low flow. Implications are that mountain front GW recharge magnitudes can control valley aquifer storage state which combined with alpine runoff magnitude and valley bottom GW discharge controls stream water quantity and geochemical composition downstream.
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17

Fiaschetti, Aaron A. "Assessment of ground water exchange in two stream channels and associated riparian zones, Jocko Valley, western Montana." CONNECT TO THIS TITLE ONLINE, 2006. http://etd.lib.umt.edu/theses/available/etd-03012007-100218/.

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18

Simon, Kevin Scott. "Organic Matter Dynamics and Trophic Structure in Karst Groundwater." Diss., Virginia Tech, 2000. http://hdl.handle.net/10919/26138.

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In this study of energy pathways in karst groundwater the first chapter examines spatial and temporal patterns of bacterial density and activity in the Dorvan-Cleyzieu karst aquifer, France. During baseflow, bacterial density and activity in the water column was similar in upper and lower zones of the aquifer. Floods apparently scoured inactive bacteria from the aquifer matrix but had little effect on respiring cells. Dissolved organic carbon was more abundant at the base of the aquifer, probably because of patchy distribution of particulate organic matter in upper aquifer zones that leached dissolved organic carbon. The temporal sequence of flooding and drying in the aquifer appears to play an important role in the maintenance of biofilms which should be important energy sources to higher trophic levels in the aquifer. The ecosystem expansion and contraction model, originally developed to describe surface streams, may be a good descriptor of spatial and temporal patterns of microbial films in karst aquifers. The process of leaf and wood breakdown in cave streams in Organ Cave, West Virginia is examined in Chapter 2. Leaf and wood breakdown rates and microbial biomass and respiration on leaves and wood were compared between cave streams with and without coarse particulate organic matter (CPOM) input from the surface to examine the role of CPOM input in leaf and wood breakdown. Breakdown rate and pattern of microbial colonization of leaves and wood were typical of results reported for surface streams. Unlike in surface streams, CPOM input did not influence breakdown rate or microbial colonization on leaves and wood, apparently because nutrients are not limiting in cave streams. Nutrient addition had little effect on microbial films on wood in either stream type. Gammarus minus is an important shredder in Organ Cave streams and G. minus colonization accelerated leaf breakdown rates. Leaf and wood transport rates were low and, when combined with breakdown rates, suggest that CPOM will be retained and transformed to fine particles near its entry point to the subsurface. In chapter 3 I examine cave stream food web structure and the role various organic matter sources in stream trophic dynamics. I used stable isotope (13C and 15N) natural abundance analysis and a 13C-acetate tracer release to establish feeding relationships and to trace the use and importance of bacterial carbon in cave streams with and without CPOM input. Cave streams contained three trophic levels consisting of organic matter sources, primary consumers, and predators. Patterns of 13C labeling in the stream were similar to that in similar studies of surface streams. 13C acetate was incorporated into epilithic biofilms and fine benthic organic matter (FBOM). Some primary consumers, Fontigens tartarea, Gyraulus parvus, and Physa were highly labeled and showed a longitudinal labeling pattern consistent with the consumption of epilithic biofilms. An epigean caddisfly, Dolophilodes, was highly labeled and probably feeds on suspended organic matter. Other primary consumers, Gammarus minus and Caecidotea holsingeri, feed on FBOM and epilithon. Two amphipods, Stygobromus emarginatus and S. spinatus, and a planarian, Macrocotyla hoffmasteri, are predators in the streams. Leaves and wood were not major energy sources directly used by stream animals. Dissolved organic matter (DOM) originating from soils appears to be the primary energy source for stream food webs by fueling bacterial production that is then used by higher trophic levels. Because epilithon C turnover times were relatively long (12.7 - 17 days), DOM can be immobilized in cave stream biofilms, enhancing the efficiency with which the microbial loop may transfer energy to higher trophic levels.
Ph. D.
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19

Schulte, Marc Alan. "Dilution Gauging as a Method to Quantify Groundwater Baseflow Fluctuations in Arizona's San Pedro River." Thesis, The University of Arizona, 1997. http://etd.library.arizona.edu/etd/GetFileServlet?file=file:///data1/pdf/etd/azu_etd_hy0133_sip1_w.pdf&type=application/pdf.

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20

Hughes, Joseph D. "Salinity- and temperature-dependent groundwater flow in the Floridan aquifer system of South Florida." [Tampa, Fla] : University of South Florida, 2006. http://purl.fcla.edu/usf/dc/et/SFE0001625.

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21

Bari, Mohammed A. "A distributed conceptual model for stream salinity generation processes : a systematic data-based approach." University of Western Australia. School of Earth and Geographical Sciences, 2006. http://theses.library.uwa.edu.au/adt-WU2006.0058.

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[Truncated abstract] During the last fifty years mathematical models of catchment hydrology have been widely developed and used for hydrologic forecasting, design and water resources management. Most of these models need large numbers of parameters to represent the flow generation process. The model parameters are estimated through calibration techniques and often lead to ‘unrealistic’ values due to structural error in the model formulations. This thesis presents a new strategy for developing catchment hydrology models for representing streamflow and salinity generation processes. The strategy seeks to ‘learn from data’ in order to specify a conceptual framework that is appropriate for the particular space and time scale under consideration. Initially, the conceptual framework is developed by considering large space and time scales. The space and time scales are then progressively reduced and conceptual model complexity systematically increased until ultimately, an adequate simulation of daily streamflow and salinity is achieved. This strategy leads to identification of a few key physically meaningful parameters, most of which can be estimated a priori and with minimal or no calibration. Initially, the annual streamflow data from ten experimental catchments (control and cleared for agriculture) were analysed. The streamflow increased in two phases: (i) immediately after clearing due to reduced evapotranspiration, and (ii) through an increase in stream zone saturated area. The annual evapotranspiration losses from native vegetation and pasture, the ‘excess’ water (resulting from reduced transpiration after land use change), runoff and deep storage were estimated by a simple water balance model. The model parameters are obtained a priori without calibration. The annual model was then elaborated by analysing the monthly rainfall-runoff, groundwater and soil moisture data from four experimental catchments. Ernies (control, fully forested) and Lemon (53% cleared) catchments are located in zone with a mean annual rainfall of 725 mm. Salmon (control, fully forested) and Wights (100% cleared) are located in zone with mean annual rainfall of 1125 mm. Groundwater levels rose and the stream zone saturated area increased significantly after clearing. From analysis of this data it was evident that at a monthly time step the conceptual model framework needed to include a systematic gain/loss to storage component in order to adequately describe the observed lags between peak monthly rainfall and runoff.
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22

Bari, Mohammed A. "A distributed conceptual model for stream salinity generation processes : a systematic data-based approach /." Connect to this title, 2005. http://theses.library.uwa.edu.au/adt-WU2006.0058.

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23

Gaona, Garcia Jaime. "Groundwater-stream water interactions: point and distributed measurements and innovative upscaling technologies." Doctoral thesis, Università degli studi di Trento, 2019. http://hdl.handle.net/11572/242544.

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The need to consider groundwater and surface water as a single resource has fostered the interest of the scientific community on the interactions between surface water and groundwater. The region below and alongside rivers where surface hydrology and subsurface hydrology concur is the hyporheic zone. This is the region where water exchange determines many biogeochemical and ecological processes of great impact on the functioning of rivers. However, the complex processes taking place in the hyporheic zone require a multidisciplinary approach. The combination of innovative point and distributed techniques originally developed in separated disciplines is of great advantage for the indirect identification of water exchange in the hyporheic zone. Distributed techniques using temperature as a tracer such as fiber-optic distributed temperature sensing can identify the different components of groundwater-surface water interactions based on their spatial and temporal thermal patterns at the sediment-water interface. In particular, groundwater, interflow discharge and local hyporheic exchange flows can be differentiated based on the distinct size, duration and sign of the temperature anomalies. The scale range and resolution of fiber-optic distributed temperature sensing are well complemented by geophysics providing subsurface structures with a similar resolution and scale. Thus, the use of fiber-optic distributed temperature sensing to trace flux patterns supported by the exploration of subsurface structures with geophysics enables spatial and temporal investigation of groundwater-surface water interactions with an unprecedented level of accuracy and resolution. In contrast to the aforementioned methods that can be used for pattern identification at the interface, other methods such as point techniques are required to quantify hyporheic exchange fluxes. In the present PhD thesis, point methods based on hydraulic gradients and thermal profiles are used to quantify hyporheic exchange flows. However, both methods are one-dimensional methods and assume that only vertical flow occurs while the reality is much more complex. The study evaluates the accuracy of the available methods and the factors that impact their reliability. The applied methods allow not only to quantify hyporheic exchange flows but they are also the basis for an interpretation of the sediment layering in the hyporheic zone. For upscaling of the previous results three-dimensional modelling of flow and heat transport in the hyporheic zone combines pattern identification and quantification of fluxes into a single framework. Modelling can evaluate the influence of factors governing groundwater-surface water interactions as well as assess the impact of multiple aspects of model design and calibration of high impact on the reliability of the simulations. But more importantly, this modelling approach enables accurate estimation of water exchange at any location of the domain with unparalleled resolution. Despite the challenges in 3D modelling of the hyporheic zone and in the integration of point and distributed data in models, the benefits should encourage the hyporheic community to adopt an integrative approach comprising from the measurement to the upscaling of hyporheic processes.
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24

Bleppony, Rueben Arnoldz. "Increased Salinity of Drilled Wells in Stockholm County – analysis of natural factors." Thesis, KTH, Mark- och vattenteknik (flyttat 20130630), 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-171823.

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Almost 50 % of drinking water in Sweden comes from aquifers. The sustainability of groundwater resources in Stockholm County is threatened by increased salinity although most of the drinking water comes from Lake Mälaren. For a region known to be located within the areas covered by seawater after the last glaciation, the health and socio-economic development of the county is in a balance as development plans are challenged by high risk of salt groundwater. It is therefore important to know the extent and spread of salinity within the areas and the factors that correlate well with the salinity in the first attempt to study the risk of the areas to high salt content of groundwater. This paper looks at the distribution of salinity within the county and analyses the correlation between salinity and several natural factors. Using well co-ordinates and chemical data (compiled by Stockholm County Administration), and digital topographical, geological and land use data (from SGU and Swedish Land Survey), it is possible to project and visualize wells and salinity over the area, spatially develop and extract natural factor values to respective wells based on their co-ordinates, and finally perform statistical analyses on a resultant well attributes table, with the aid of Surfer, ArcGIS and Statistica Software. Results showing the spatial distribution of wells’ salinity and graphs of variance between the salinity of wells and respective natural factors of topography, depth, predominant soil cover, land use and distance from the sea, are further discussed.
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25

Dadakis, Jason Sophocles. "Isotopic and geochemical characterization of recharge and salinity in a shallow floodplain aquifer near El Paso, Texas." Thesis, The University of Arizona, 2004. http://etd.library.arizona.edu/etd/GetFileServlet?file=file:///data1/pdf/etd/azu_e9791_2004_039_sip1_w.pdf&type=application/pdf.

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26

Dehkordi, S. Emad. "Groundwater resources in coastal hard rock terrains : Geostatistical and GIS approach." Thesis, KTH, Mark- och vattenteknik, 2009. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-151296.

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Stockholm archipelago is a combination of coastal and young glaciated conditions on hard rock geology with almost no primary porosity and very limited secondary porosity. Therefore the aquifer is both of limited capacity and exposed to salinity problem. In this context importance of fractures and soil cover is magnified. Lineaments are representatives of fractures in remote sensing. Fracture mapping in study area proves close correspondence between orientation of fractures and nearly located lineaments. Especially in this type of terrain, lineaments normally occur together with many other interesting hydrogeological features such as topographic attributes, soil, and vegetation; however, still each of these factors has its own effect on the groundwater situation. Through employment of geostatistical analysis and a modified variant of the RV (Risk Variable) method, called the PV (Probability Value) method, different attributes are rated by importance. The results show, soil cover is the most influencing factor then rock type and distance from lineaments; other factors are classified after them. It is discovered that the center of lineaments may not be the most suitable site to extract water because of being clogged by fills. This is particularly the case for shear fractures in which clay can be internally formed due to friction. Based on the statistical results a model is made in GIS environment in order to create hydrogeological maps. Such maps, after validation, can be used for any other area with similar properties even with missing or very limited data from boreholes. These maps definitively are only probability maps projecting areas with higher and lower prospect of aquifer potential and cannot guarantee high capacity in every borehole drilled in designated areas due to high heterogeneity of fractured rock system. Analysis of chemical data from wells proves a correlation between fracture orientations and topography with salinization and groundwater flow. Groundwater flow in the surroundings seems to be essential for feeding the aquifer as most of the wells with increased salt content have also low capacities.
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Brown, Krista M. "GROUNDWATER-STREAM INTERACTIONS AND WATER QUALITY OF FORMER DAM RESERVOIRS IN NORTHEAST, OHIO." Kent State University / OhioLINK, 2019. http://rave.ohiolink.edu/etdc/view?acc_num=kent1564530847224908.

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28

Anderman, Evan R. Poeter Eileen P. "Field verification of stream-aquifer interactions Colorado School of Mines survey field, Golden, Colorado /." Fort Collins, Colo. : Colorado Water Resources Research Institute, Colorado State University, 1993. http://hdl.handle.net/10176/co:4527_ucsu61410169internet.pdf.

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Thesis (M. Eng.)--Colorado School of Mines, 1993.
Thesis advisor: Eileen Poeter, Dept. of Geology and Geological Engineering. Includes bibliographical references (leaves 93-97). Includes bibliographical references (p. 93-97). Also available in print version.
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29

Simpson, Trevor Baylie. "Understanding the groundwater system of a heavily drained coastal catchment and the implications for salinity management." Thesis, Cranfield University, 2007. http://dspace.lib.cranfield.ac.uk/handle/1826/2460.

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The Thurne catchment in north-east Norfolk, UK, is an extremely important part of the Broads National Park, an internationally important wetland environment. Extensive engineered land drainage of the marshes of this low-lying coastal catchment over the past two centuries has led to land subsidence and the need for drainage pumps to control water levels sufficiently below sea-level to maintain agricultural productivity. Consequently, seawater from the North Sea has intruded into the underlying Pleistocene Crag (sand) aquifer and brackish groundwater enters into land drainage channels, thereby raising their salinity. Powerful pumps discharge these brackish drainage waters into a Special Area of Conservation (SAC) and RAMSAR site, leading to adverse ecological impacts on salt-sensitive species. Chloride concentrations within drainage channels throughout the network have been found to significantly vary, with several influential factors affecting channel salinity such as proximity to the sea and connectivity to the underlying aquifer. A thorough understanding of the surface-water/groundwater system and a subsequent quantification of the various processes has been necessary for the development for the drain/aquifer interactions and a numerical groundwater model. These models are used to estimate the long-term distribution of the salinity within the drainage system under current conditions. The model credibility is justified by comparable aquifer-drain water balance, a comparable coast water inflow/ total groundwater ratio and the particle tracking from the coastal reaches trace to previously-measured saline-vulnerable locations. The numerical groundwater model has demonstrated that the average daily inflow of saline groundwater into the Crag aquifer of the Thurne catchment is 3,081 m3/day, of which the HempsteadMarshes main drain is one of the main conduits for saline inflow into the Brograve system, which discharges directly into the SAC. Various changes to the engineering design or operation of the drainage system have been proposed to minimise the saline inflow to the SAC, but the implementation of any proposals must be considered in conjunction with the current dynamics of the system. Three separate management or engineering remedial measures have been modelled: (i) raising the water levels in the drains of the Hempstead Marshes in the north east of the catchment (ii) lining the main drain of the HempsteadMarshes with low permeability material, and (iii) The construction of a new coastal open ditch drain which is intended to ‘intercept’ the saline intrusion and prevent ingress into inland drains of the Brograve system. The results suggest that raising the water levels in the Hempstead Marshes will reduce the saline inflow into the Brograve sub-catchment substantially, and decrease the overall saline inflow into the Thurne catchment from 3081 m3/day to 2822 m3/day). The lining of the main drain in Hempstead produces a less than 10% decrease in saline inflow into the catchment from 3,081 m3/day to 2,958 m3/day. The simulated coastal interceptor drain could in theory through maintaining a low groundwater head near the coast, prevent the inflow of saline groundwater into the Brograve system. However, such a drain would increase the saline inflow across the coastal boundary by around six times (from 3,081 m3/day to 19,750 m3/day), remove large quantities of fresh groundwater from the Pleistocene Crag aquifer and lead to high energy and pumping costs. The research has shown that there are partial solutions to reducing the saline inflow into the drainage systems in this lowland coastal catchment. However, any intended alterations must first consider other potential impacts, such as changes to flood risk, land management restrictions or hydrodynamic effects on the receiving watercourse through changed discharge volumes.
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30

Dogramaci, Shawan Shawket. "Isotopes of sulphur, oxygen, strontium and carbon in groundwater as tracers of mixing and geochemical processes, Murray Basin, Australia /." Title page, table of contents and abstract only, 1998. http://web4.library.adelaide.edu.au/theses/09PH/09phd654.pdf.

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31

Funkhouser, Lyndsey Karin. "Determination of the location of the groundwater divide and nature of groundwater flow paths within a region of active stream capture; the New River watershed." Thesis, Virginia Tech, 2014. http://hdl.handle.net/10919/64286.

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The relatively rapid stream capture of the New River basin by the Roanoke River basin provides a unique example of topographic change within a tectonically inactive environment. A previous investigation of abandoned river deposits has shown the capture of ~225 km2 of New River basin area, which has caused approximately 250 m of incision by the Roanoke River (Prince et al., 2011). Difference in base level elevations between the lower Roanoke to the higher New River could be the source of potential energy driving rapid incision (Prince et al., 2011). Significant incongruities in base level elevations at the boundaries of an aquifer can steepen the gradient and shift the groundwater divide further toward the higher elevation boundary (Yechieli et al., 2009). If a steep groundwater gradient and expanded groundwater basin exists beneath the Roanoke River tributaries, this would suggest a groundwater control on incision and capture. In this investigation we incorporate average total head, measured from 18 domestic wells, and constant-head river boundary conditions into numerical models to calculate water levels and gradients between the rivers. We also utilized thermal patterns and particle tracking of spring locations to better understand flow paths in the region. Our results show the groundwater divide is shifted toward the higher elevation boundary, indicating that the groundwater basin is captured prior to surface capture. Flow pathways utilized by groundwater capture can be either diffuse or conduits, however further work should be done to better understand travel times and flow depths.
Master of Science
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32

Altevogt, Andrew Sarosh. "Soil gas analysis as a predictor of VOC concentrations in groundwater and stream inflow." Thesis, Massachusetts Institute of Technology, 1994. http://hdl.handle.net/1721.1/35380.

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33

Vionnet, Leticia Beatriz, and Leticia Beatriz Vionnet. "Investigation of stream-aquifer interactions using a coupled surface water and groundwater flow model." Diss., The University of Arizona, 1995. http://hdl.handle.net/10150/187414.

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A finite element numerical model is developed for the modeling of coupled surface-water flow and ground-water flow. The mathematical treatment of subsurface flows follows the confined aquifer theory or the classical Dupuit approximation for unconfined aquifers whereas surface-water flows are treated with the kinematic wave approximation for open channel flow. A detailed discussion of the standard approaches to represent the coupling term is provided. In this work, a mathematical expression similar to Ohm's law is used to simulate the interacting term between the two major hydrological components. Contrary to the standard approach, the coupling term is incorporated through a boundary flux integral that arises naturally in the weak form of the governing equations rather than through a source term. It is found that in some cases, a branch cut needs to be introduced along the internal boundary representing the stream in order to define a simply connected domain, which is an essential requirement in the derivation of the weak form of the ground-water flow equation. The fast time scale characteristic of surface-water flows and the slow time scale characteristic of ground-water flows are clearly established, leading to the definition of three dimensionless parameters, namely, a Peclet number that inherits the disparity between both time scales, a flow number that relates the pumping rate and the streamflow, and a Biot number that relates the conductance at the river-aquifer interface to the aquifer conductance. The model, implemented in the Bill Williams River Basin, reproduces the observed streamflow patterns and the ground-water flow patterns. Fairly good results are obtained using multiple time steps in the simulation process.
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34

Gaona, Jaime [Verfasser]. "Groundwater-stream water interactions: point and distributed measurements and innovative upscaling technologies / Jaime Gaona." Berlin : Freie Universität Berlin, 2020. http://d-nb.info/1215099495/34.

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35

Duvert, Clement. "Stream & groundwater responses to episodic recharge: Integrating time-series analysis & environmental tracers." Thesis, Queensland University of Technology, 2016. https://eprints.qut.edu.au/94989/12/Clement_Duvert_Thesis.pdf.

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This dissertation examines the hydrological response of aquifers and streams subjected to highly episodic recharge. Based on high-resolution measurements of a range of novel hydrochemical and isotopic tracers, it is demonstrated that (i) inter-aquifer mixing can be triggered by major recharge events and (ii) the transit time of the groundwater contribution to streams varies considerably with varying recharge rates. These findings suggest that stream–aquifer and inter-aquifer interactions are highly preferential both spatially and temporally, with important implications for the conceptualisation of hydrological processes in complex geological settings.
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36

Al-Ajmi, Asadullah. "Modelling the development of soil salinity on small farms in Oman growing irrigated crops using saline groundwater." Thesis, University of Reading, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.340010.

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37

Nygren, Anton, Edvard Nordenskjöld, and Erik Östblom. "Groundwater occurrence and quality in Bulawayo province, Zimbabwe." Thesis, Uppsala universitet, Institutionen för geovetenskaper, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-300718.

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This study focused on determining the groundwater flow paths in the crystalline subsurface rocks of the Bulawayo metropolitan, Zimbabwe, through analysing the discontinuities of the electrical properties of the ground, as well as in the magnetic field of the underlying rocks. Further, borehole water quality was analysed by measuring and mapping several chemical parameters, specifically TDS, salinity and the electrical conductivity. The electrical and magnetic anomalies were measured at two field sites within the Bulawayo province, the Harry Allen Golf Course and the Barbour Fields dumpsite, while 120 boreholes were sampled for water quality in a large part the province. Two magnetometers were used to measure the magnetic field and the time and location of the measurements, which resulted, after processing in SURFER, into the magnetic field map of these areas. This was used, in conjunction with the geologic map of the Bulawayo province, in order to determine useful locations for the electrical resistivity surveys. These included electrical resistivity tomography and vertical electrical sounding and were performed with an earth resistivity/induced polarization (IP) meter in order to measure the electrical resistivity of the ground. Inverse modelling was used in the RES2DINV software program to produce the topographic image of resistivity. The results for the borehole sampling showed that the maps for the three chemical parameters were very similar, with the western and northern parts of the mapped area displaying higher concentration values. The results of the electrical resistivity surveying showed probable areas of groundwater flow with its relationship to electric conductivity.
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38

Nelson, Tom. "Feasibility of Extending an Artificial Salmon Spawning Stream, Marx Creek Near Hyder, Alaska." DigitalCommons@USU, 2010. https://digitalcommons.usu.edu/etd/541.

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Marx Creek, near Hyder in southeast Alaska, is a groundwater-fed, artificial salmon-spawning stream that was constructed to enhance the habitat of the atypically large chum salmon. The success of the upper Marx Creek has been limited primarily by the infiltration of silty water from the Salmon River through its flood-control dike, which results in a turbid stream environment that is not conducive to salmon spawning. The purpose of this project was to determine whether baseflow from the groundwater system is sufficient to support a proposed 1,000-foot extension of Marx Creek. The extension would be constructed approximately 500 feet east of the existing channel, and would connect with the existing Marx Creek at a point downstream of the sediment-settling stream cell. The location of the new channel would prevent the turbid water from reaching the new channel, as it would flow into and settle out in the existing Marx Creek. In order to accomplish this purpose, 20 monitoring wells were installed. Water level data were collected in each of the monitor wells. Slug and pumping tests were performed to determine the hydraulic conductivity at each of the well locations. Discharge measurements were also collected in July 2006 and July 2007. These data were used to create a three-dimensional groundwater flow model using Visual MODFLOW. The model was calibrated to hydraulic head measurements and Marx Creek discharge. After achieving model calibration, three predictive simulations were run. In the first simulation the proposed extension was added to the calibrated model. The result was that baseflow to the extension significantly exceeded baseflow to Marx Creek, and that the addition of the proposed extension reduced baseflow to Marx Creek by 17%. In the second simulation, Marx Creek was removed from the model, while the proposed extension remained. The result was that discharge in the extension increased by 5%. In the third simulation a 1.06-foot drop in the model's hydraulic head was simulated, and the result was that discharge in the extension decreased by 18%. Based on these results, it is likely that baseflow to the proposed extension would be sufficient to provide habitat conducive to salmon spawning.
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39

Schmadel, Noah M. "Quantifying Surface Water and Groundwater Interactions in a High-Gradient Mountain Stream for Solute Transport." DigitalCommons@USU, 2009. https://digitalcommons.usu.edu/etd/486.

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A study reach in a mountain stream highly influenced by groundwater was selected to test common data collection strategies used to characterize and quantify groundwater exchange processes necessary to predict solute transport. The data types collected include: high frequency discharge estimates with the use of rating curves, dilution gauging techniques with instantaneous tracer experiments, groundwater table and stream water surface elevations, vertical head gradients, and hydraulic conductivity estimates. The first two data types were categorized as stream gauging and the remaining three data types as site characterization. The stream gauging data were used to quantify net changes in stream discharge at a reach scale with rating curve predictions and dilution gauging. Each method resulted in opposite net changes at this scale. An error analysis regarding rating curve predictions and dilution gauging suggested that neither method detected groundwater exchange at this scale due to discharge estimates being statistically the same. The error in rating curve predictions was estimated using a 95% joint confidence region of model parameters and the error in dilution gauging was estimated using a first order error analysis. Dilution gauging was also performed at a sub-reach scale to quantify net changes and indicated the groundwater exchange was highly spatially variable, which was not concluded at the reach scale. To quantify a water balance more representative of the exchanges occurring, gross gains and gross losses were quantified by measuring tracer mass recoveries and were found to occur in every sub-reach. However, the error analysis concluded that nearly half of the changes were not significant, which emphasized the importance of quantifying error in stream gauging techniques used to understand surface water-groundwater interactions. The site characterization data were used to test and verify the water balance results by providing information regarding general trends and spatial variability of surface water-groundwater interactions. This study proved that one data type is not adequate to clearly characterize and quantify surface water-groundwater interactions and researchers must exercise caution when interpreting results from different data types at varying spatial scales.
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40

Biedler, Murray W. "Delineation of buried stream channels using geophysical techniques." Thesis, Rhodes University, 1994. http://hdl.handle.net/10962/d1005498.

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This study sets out to evaluate the use of geophysical methods for delineating buried stream channels, which can act as zones of preferential flow within a less hydraulically conductive aquifer. This information is important for gaining an understanding of flow dynamics of alluvial systems. The most reliable method of delineating the dimensions of aquifers is by drilling, which is an expensive proposition and is best preceded by a preliminary geophysical study to help define target zones for a drilling program. The study area is located adjacent to the Coerney River in the Sundays River Valley. Geologically it consists of approximately 5 metres of alluvial fines, covering 3 metres of coarse cobbles and boulders, all underlain by alternating siltstone and sandstone beds of indeterminate thickness. Throughout the area the water is very shallow at approximately 2 metres depth and the groundwater tends to be very saline. An air photo study revealed an old oxbow channel that had been covered over by subsequent agricultural land use. The geophysical methods available for the study were portable seismic refraction, electrical resistivity and electromagnetics. Preliminary field tests clearly showed that seismics did not produce valid results. The methods of electrical resistivity and electromagnetics produced good data and were subjected to further assessment. A grid was surveyed over the study area and both geophysical methods were applied at regularly spaced stations. Soil samples were taken over the same survey grid and analyzed for electrical conductivity in a soils laboratory. The results were compared to the geophysical data in an attempt to quantify the relationship between geophysical response and soil salinity. The data from the electromagnetic survey showed areas of low electrical conductivity which was a possible indication of zones of preferential groundwater flow. A transect of boreholes was drilled over selected electrical conductivity lows and successfully intersected the buried stream channel. A comparison of the borehole logs with the layered earth models from the Vertical Electrical Soundings indicated that the electrical resistivity method was not responding to the features of the buried stream channel and the cobblestone layer. This proved the electromagnetic method to be more valuable for this particular study
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41

Tinney, James Craig 1950. "Trading quality for quantity : an assessment of salinity contamination generated by groundwater conservation policy in the Tucson Basin." Diss., The University of Arizona, 1987. http://hdl.handle.net/10150/191122.

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The State of Arizona adopted strict groundwater conservation policies under the Arizona Groundwater Act of 1980. The Act mandates direct controls on groundwater use and provides incentives to seek alternative water supplies to offset the groundwater overdraft and restrict the expansion of municipal well fields. The City of Tucson, to reduce its groundwater dependency, is contracting for Central Arizona Project (CAP) water. CAP water comes from the Colorado River and carries with it nearly a ton of salts per acre-foot. Conservation programs being investigated by the city include reclaimed wastewater reuse for municipal use and artificial recharge. Salinity, a conservative contaminant, will rise as the water carrying it evaporates away during use. Some saline incidental recharge from wastewater irrigated acreage in the municipal well field is picked-up by groundwater pumpage in what is described as the municipal water-salinity cycle. The rate of salinity pick-up is compounded in the cycle. Those responsible for achieving groundwater conservation under the mandates of the Act do not include the costs generated by salinity damages and suffered by municipal water-consumers into their conservation plans. Salinity damages costs are generated by the direct use of CAP water and the use of degraded groundwater supplies. The study results show that under assumptions of limited groundwater dilution volumes the annual rate of salinity pick-up can range from about 1.4 percent to nearly 2.0 percent. An annual average pick-up rate of 2.0 percent could degrade Tucson's groundwater supplies from the present average salinity of 300 mg/1 to 1000 mg/1 in 61 years. Thirteen scenarios were evaluated and the present value of incremental costs of both salinity damage and expenditures associated with conservation were calculated. While estimates of salinity damage costs are many times lower than the conservation program expenditures, increased salinity in groundwater will lower the future capital value of the resource in the future if ignored.
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42

Brown, Benjamin J. Daniels William H. "Evaluation of three fish species for culture using low salinity groundwater in the Black Belt region of Alabama." Auburn, Ala., 2007. http://repo.lib.auburn.edu/2007%20Fall%20Theses/Brown_Benjamin_56.pdf.

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43

Harper-Smith, Sarah. "Modeling relative effects of riparian cover and groundwater inflow on stream temperature in lowland Whatcom County, Washington /." Online version, 2008. http://content.wwu.edu/cdm4/item_viewer.php?CISOROOT=/theses&CISOPTR=288&CISOBOX=1&REC=6.

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44

Tripathi, Ganesh N. "SPATIO-TEMPORAL VARIABILITY IN GROUNDWATER DISCHARGE AND CONTAMINANT FLUXES ALONG A CHANNELIZED STREAM IN WESTERN KENTUCKY." UKnowledge, 2013. http://uknowledge.uky.edu/ees_etds/13.

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Spatio-temporal variability in groundwater discharge and contaminant fluxes along a channelized stream in western Kentucky Surface and groundwater discharges and contaminant fluxes can vary with time and space depending upon the hydrogeological processes and geological setting of the area of interest. This study examined a ~300-m-long, channelized reach of a first-order perennial stream, Little Bayou Creek, in the Coastal Plain of far western Kentucky during the period October 2010–February 2012. Along the study reach, springs discharge groundwater contaminated by the chlorinated organic compound trichloroethene (TCE) and radionuclide technetium-99 (99Tc) released as a result of past activities at the U.S. Department of Energy’s Paducah Gaseous Diffusion Plant. The study addressed variability in groundwater discharge patterns and contaminant concentrations at various timescales (seasonal, annual, and decadal) and the extent to which the discharge sites are spatially persistent. Understanding patterns of groundwater discharge along a stream can be important for assessing the fate and transport of aqueous contaminants. Groundwater discharge was estimated during baseflow conditions using different mass-balance approaches, including velocity-area and dye-dilution gauging. Discharge fluctuated seasonally but typically increased downstream, indicating the entire study reach to be gaining throughout the year. Discharge rates of individual springs also fluctuated seasonally. Tracer test data were utilized to model flow and transient storage along the reach using the USGS software OTIS-P. Cross-sectional area determined from OTIS-P was similar to that measured by velocity-area gauging. Reach area-normalized discharge fluxes were comparable to values determined by Darcy’s law calculations from a pair of monitoring wells at the downstream end of the study reach. Temperature data acquired from probing along grids in winter and summer, from fiber-optic sensing along the reach in autumn, and from data-loggers and manual measurements in springs were used to delineate focused discharge locations. Comparison of temperature-probing results with prior studies indicated that locations of some springs persisted over a decade, whereas other springs emerged and disappeared. Because the stream is located in unlithified sediments, discharge rates of springs appear to fluctuate with soil piping and collapse along joints in fractured clay. Contaminant concentrations in springs decreased downstream along the reach and were lower than observed during September 1999 – May 2001. The continued occurrence of dissolved oxygen and the absence of TCE daughter products in springs suggest that the decrease in TCE concentrations resulted from the installation of upgradient extraction wells, rather than from intrinsic reductive degradation. KEYWORDS: Contaminant fluxes, trichloroethene, technetium-99, baseflow, temperature probing.
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45

Hartenstine, Sandra A. "Nutrient Standing Stocks and Partitioning in a Forested Coastal Plain Watershed: Groundwater, Stream and Marsh Creek." W&M ScholarWorks, 1991. https://scholarworks.wm.edu/etd/1539617639.

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46

Azinheira, David Lee. "Complementary Effects of In-Stream Structures and Inset Floodplains on Solute Retention." Thesis, Virginia Tech, 2013. http://hdl.handle.net/10919/51046.

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The pollution of streams and rivers is a growing concern, and environmental guidance increasingly suggests stream restoration to improve water quality. �Solute retention in off channel storage zones such as hyporheic zones and floodplains is typically necessary for significant reaction to occur. �Yet the effects of two common restoration techniques, in stream structures and inset floodplains, on solute retention have not been rigorously compared. �We used MIKE SHE to model hydraulics and solute transport in the channel, inset floodplain, and hyporheic zone of a 2nd order stream. �We varied hydraulic conditions (winter baseflow, summer baseflow, and storm flow), geology (hydraulic conductivity), and stream restoration design parameters (inset floodplain length, and presence of in stream structures). �In stream structures induced hyporheic exchange during summer baseflow with a low groundwater table (~20% of the year), while floodplains only retained solutes during storm flow conditions (~1% of the year). �Flow through the hyporheic zone increased linearly with hydraulic conductivity, while residence times decreased linearly. �Flow through inset floodplains and residence times in both the channel and floodplains increased non linearly with the fraction of bank with floodplains installed. �The fraction of stream flow that entered inset floodplains was one to three orders of magnitude higher than that through the hyporheic zone, while the residence time and mass storage in the hyporheic zone was one to five orders of magnitude larger than that in floodplain segments. �Our model results suggest that in stream structures and inset floodplains are complementary practices.
Master of Science
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47

Loan, Lisien. "The response of native vegetation to rising groundwater and salinity levels in the upper south east of South Australia /." Title page, contents and abstract only, 1993. http://web4.library.adelaide.edu.au/theses/09AR/09arl795.pdf.

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48

Simpson, Scott. "Modeling Stream-Aquifer Interactions During Floods and Baseflow: Upper San Pedro River, Southeastern Arizona." Thesis, The University of Arizona, 2007. http://hdl.handle.net/10150/193338.

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Streams and groundwaters interact in distinctly different ways during flood versus base flow periods. Recent research in the Upper San Pedro River using isotopic and chemical data shows that (1) near-stream, or 'riparian,' groundwater recharged during high streamflow periods is a major contributor to streamflow for the rest of the year, and (2) the amount of riparian groundwater derived from this flood recharge can vary widely (10-90%) along the river. Riparian groundwater in gaining reaches is almost entirely basin groundwater, whereas losing reaches are dominated by prior streamflow.This description of streamflow gives rise to the questions of (1) how much flood recharge occurs at the river-scale, and (2) subsequently, what is the relative importance of flood recharge and basin groundwater in maintaining the hydrologic state of the riparian system. To address these questions, a coupled hydrologic-solute model was constructed for 45 km of the Upper San Pedro riparian system.
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49

McNeil, Vivienne Heather. "Assessment methodologies for very large, irregularly collected water quality data sets with special reference to the natural waters of Queensland." Thesis, Queensland University of Technology, 2001.

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50

Brown, Brendan. "Arsenic transport in groundwater, surface water, and the hyporheic zone of a mine-influenced stream-aquifer system." Thesis, Virginia Tech, 2005. http://hdl.handle.net/10919/36197.

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We investigated the transport of dissolved arsenic in groundwater, surface water and the hyporheic zone in a stream-aquifer system influenced by an abandoned arsenopyrite mine. Mine tailing piles consisting of a host of arsenic-bearing minerals including arsenopyrite and scorodite remain adjacent to the stream and represent a continuous source of arsenic. Arsenic loads from the stream, springs, and groundwater were quantified at the study reach on nine dates from January to August 2005 and a mass-balance approach was used to determine hyporheic retention. Arsenic loading from the groundwater was the dominate source of arsenic to the stream, while loads from springs represented a substantial proportion of the total arsenic load during spring. Arsenic loads in surface and groundwater were significantly elevated during summer. Elevated temperatures during summer may lead to increased arsenic loading by increasing dissolution rate of arsenic source minerals and/or increases in microbially-mediated dissolution processes. The hyporheic zone was shown to be retaining arsenic in the upstream-most sub-reach. Retention most likely occurs through the sorption of dissolved arsenic onto hyporheic sediments. In downstream sub-reaches, hyporheic sediments are derived from mine-tailing piles which have high arsenic content. The hyporheic zone in these sub-reaches was shown to be releasing dissolved arsenic. The historic influence of mining activity has resulted in multiple sources of arsenic to the stream which has increased arsenic contamination of the surface waters.
Master of Science
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