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Dissertations / Theses on the topic '"street chemistry"'

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Published: 30 May 2022
Last updated: 31 May 2022

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1

Bright, Vivien Bianca. "Street canyon atmospheric composition : coupling dynamics and chemistry." Thesis, University of Birmingham, 2013. http://etheses.bham.ac.uk//id/eprint/4414/.

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A new model for the simulation of street canyon atmospheric chemical processing has been developed, by integrating an existing Large-Eddy Simulation (LES) dynamical model of canyon atmospheric motion with a detailed chemical reaction mechanism, the Reduced Chemical Scheme (RCS), comprising 51 chemical species and 136 reactions, based upon a subset of the Master Chemical Mechanism (MCM). The combined LES-RCS model is used to investigate both the effects of mixing and chemical processing upon air quality within an idealised street canyon. The effect of the combination of dynamical (segregation) and chemical effects is determined by comparing the outputs of the full LES-RCS canyon model with those obtained when representing the canyon as a zero-dimensional box model (i.e. assuming mixing is complete and instantaneous). The LES-RCS approach predicts lower (canyon-averaged) levels of NOX, OH and HO2, but higher levels of O3, compared with the box model run under identical chemical and emission conditions. Chemical processing of emissions within the canyon leads to a significant increase in the Ox flux from the canyon into the overlying boundary layer, relative to primary emissions, for the idealised case and a number of pollution scenarios considered. These results demonstrate that within-canyon atmospheric chemical processing can substantially alter the concentrations of pollutants injected into the urban canopy layer, compared with the raw emission rates within the street canyon and that such variations have a considerable effect on average within canyon concentrations and the flux of pollutants out of the canyon into the urban background environment.
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Minakova, K., Serhii Petrov, and S. Radoguz. "How "Street chemistry" and "Street physics" settled at the National Technical University "Kharkiv Polytechnic Institute"." Thesis, Copissaurio Repro – Centro Imp. Unip. Lda. Campus de Gualtar, 2018. http://repository.kpi.kharkov.ua/handle/KhPI-Press/46263.

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3

Williams, Burnett Mia Laverne. "Exploring the Multiplex Detection Capabilities of Raman Spectroscopy on Mock Street Samples Containing Illicitly Manufactured Fentanyls." Wright State University / OhioLINK, 2020. http://rave.ohiolink.edu/etdc/view?acc_num=wright1580817621806717.

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4

Hirst, Heike. "Ecological influences on diatom assemblage responses to stream chemistry." Thesis, Cardiff University, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.398817.

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Moore-Maley, Benjamin Lee. "The inorganic carbonate chemistry of the southern Strait of Georgia." Thesis, University of British Columbia, 2014. http://hdl.handle.net/2429/51770.

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A one-dimensional, biophysical, mixing layer model was modified to hindcast pH and aragonite saturation state (OmegaA) in the southern Strait of Georgia. The model skill in predicting spring phytoplankton bloom timing in previous studies was a key factor in its selection. Dissolved inorganic carbon (DIC) and total alkalinity (TA) were added as state variables, coupled to the existing nitrogen-based biological equations. Additional processes determined to be important to the system such as air-sea gas exchange and nutrient-limited excess carbon uptake were also implemented. pH and OmegaA could then be calculated from DIC and TA. Modeled DIC, TA, pH, and OmegaA were evaluated against data collected between 2003 and 2012. Modeled and observed quantities agreed except in some summers, with surface disagreement driven primarily by plume variability and subsurface disagreement driven primarily by model overproductivity. Model outputs demonstrated a near-surface seasonal cycle characterized by low pH and OmegaA in winter and high pH and OmegaA in summer. In order to evaluate the sensitivity of model pH and OmegaA to local forcing quantities, the model was run in one year increments over the period from 2001 through 2012. For each year, each of three forcing records (wind speed, freshwater flux, cloud fraction) was shifted across all possible years during the same period for a total of 432 experimental runs. When regressed against spring wind speed, model surface pH demonstrated a clear, negative correlation. Model spring OmegaA demonstrated a negative correlation to cloud fraction. Summer pH and OmegaA were most sensitive to freshwater flux, both showing negative correlations. Model pH and OmegaA sensitivity to freshwater TA and pH were also evaluated over the same period using a set of realisitic freshwater chemistry scenarios determined from observations in the Fraser River. Model pH and OmegaA demonstrated opposite correlations to freshwater TA with sensitivities at opposite extremes of freshwater pH. The sensitivity results identify important links between local processes and the carbonate chemistry in the southern Strait of Georgia, and perhaps provide some simple forecasting tools to be tested in the future.
Science, Faculty of
Earth, Ocean and Atmospheric Sciences, Department of
Graduate
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Hui, Cheng. "Air-Stream-Assisted Electrospinning." University of Akron / OhioLINK, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=akron1491920416271494.

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7

Foster, Helen Jane. "Assessment and modelling of spatio-temporal variability in upland stream chemistry." Thesis, Imperial College London, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.342328.

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8

Oluju, Philemon. "Literature Review of the impacts of riparian vegetation on stream chemistry." Thesis, Högskolan i Halmstad, Akademin för ekonomi, teknik och naturvetenskap, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:hh:diva-35206.

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Water quality in streams around the world continues to be degraded by a series of human activities that feed pollutants into the vulnerable stream ecosystem via surface and subsurface runoff. This continues to accelerate global biodiversity and habitat losses within the stream environments and across entire watersheds with net adverse effects on public health and the ability of communities and ecosystems to adapt or become resilient to the prevalent impacts of climate change. One commonly used approach for protecting stream water from pollution is the use of vegetated riparian buffer zones to mitigate pollutants in surface and subsurface runoff prior to runoff entry into the stream channel. The optimal success of this approach requires land and water resource managers to understand the mechanisms by which riparian buffer zones function and the full range of factors that influence the effectiveness of riparian buffer vegetation in abating stream water pollution. Despite this need, resource managers in different geographical locations around the world still struggle to understand the linkages between riparian vegetation and stream chemical quality. This literature review therefore sought to synthesize findings from various scientific articles on the ways in which the major attributes of riparian vegetation [type, age, width, restoration and shading effect] influence the effectiveness of riparian vegetation in protecting the chemical quality of water in streams. This was aimed at generating conclusions and perspectives that could improve academic knowledge and natural resource managers’ understanding of the intricate linkage between riparian vegetation and changes in water chemistry. The study finds that the factors of riparian vegetation type, age, width, restoration and shading effects require due consideration in the development of riparian buffer zone and stream water chemical quality management interventions. I find that these factors require a high degree of integration, triangulation and context-specificity to achieve the objectives of riparian management intervention. I further find that stream water quality decision-making processes need to combine riparian vegetation-based approaches with other measures for mitigating and containing the spillage of pollutants at the source.

Presentation was conducted via Skype

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9

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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Amaning, Kwarteng. "Streamwater and sediment chemistry of Ohio's Western Allegheny Plateau ecoregion and their relation to aquatic life." Ohio : Ohio University, 2006. http://www.ohiolink.edu/etd/view.cgi?ohiou1153757100.

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11

Bopp, Jesse A. "Combined effects of water chemistry, canopy cover, and stream size on benthic macroinvertebrates along a central Appalachian stream continuum." Morgantown, W. Va. : [West Virginia University Libraries], 2002. http://etd.wvu.edu/templates/showETD.cfm?recnum=2474.

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Thesis (M.S.)--West Virginia University, 2002.
Title from document title page. Document formatted into pages; contains viii, 96 p. : ill., maps (some col.). Includes abstract. Includes bibliographical references (p. 41-51).
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12

Hall, Tavenner Marie. "Evaluating changes in strontium chemistry of stream water in response to environmental stress." Thesis, Massachusetts Institute of Technology, 1995. http://hdl.handle.net/1721.1/54408.

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Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Earth, Atmospheric, and Planetary Sciences, 1995.
Includes bibliographical references (leaves 47-49).
by Tavenner Marie Hall.
M.S.
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13

Winland, Ronald Lee. "Acid Coal Mine Drainage in Ohio: Stream Water Quality, Precipitate Chemistry and Mineralogy." The Ohio State University, 1989. http://rave.ohiolink.edu/etdc/view?acc_num=osu1391770757.

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14

Stirling, M. W. "Contrasts in stream water chemistry impact aquatic ecosystem functioning in an agricultural landscape." Thesis, University of Reading, 2016. http://centaur.reading.ac.uk/66295/.

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Given the importance of freshwater ecosystems to human health and wellbeing, the resilience of aquatic communities to pollution from a variety of sources is of increasing concern. Current indices concentrate on structural measures to define stream health. These include community assemblages, in-stream water chemistry, and hydrological impairment through physical modifications. However, ecosystem services provided by freshwater communities rely on the underlying biogeochemical cycles that are a function of metabolic processes. At present, these are not routinely used in assessments of ecological status. A paired sub-catchment approach was used to study the effects of different land management practices on in-stream water chemistry, and their consequences to aquatic functional integrity in an agricultural landscape. The study provided an opportunity to assess the potential for ecosystem functional measures to complement the structural measures that are used to define impact on aquatic communities. High resolution analysis of the nutrient chemistry within two study reaches underpinned comparisons of community aerobic respiration, greenhouse gas transfer across the sediment-water interface and macro-invertebrate mediated processing of organic matter. This programme of measures identified clear differences between the study sub-catchments. It revealed that the management of animal waste, and control on the delivery of fine sediments to a watercourse, were key influences on in-stream functional integrity. The delivery of inorganic nutrients as a result of fertiliser application was also evident. However, the significance of this signal was masked by the overriding effect of high loads of organically loaded fine sediments and low flow in the Priors Farm reach.
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15

Staines, Russell. "The influence of geology on small scale spatial changes in stream water chemistry." Thesis, University of Aberdeen, 1998. http://digitool.abdn.ac.uk/R?func=search-advanced-go&find_code1=WSN&request1=AAIU115813.

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The influence of geology on small scale spatial changes in stream water chemistry has been investigated in the Allt Fileachaidh and Allt an t-Sneachda catchments, in Glen Muick (NE Scotland), using both field and laboratory studies. This research was carried out with the specific aim of investigating the use of small scale spatial changes in stream water chemistry as a geological/geochemical mapping tool. For this purpose, the use of stream water has been compared to the use of stream sediment, a more traditional geochemical sample medium. In addition, the transferability of the method has been investigated in a geologically well exposed Arctic environment by a study of three catchments in Svalbard. The major findings of the research are as follows: (i) In the Allt Fileachaidh and Allt an t-Sneachda catchments, small scale downstream changes in stream water chemistry, in particular the concentrations of Si, Ca, Mg, Na, K and inorganic C, were associated with changes in the underlying geology; (ii) Mineralogical composition, and not bulk lithochemistry, was the most important feature of the bedrock in Glen Muick, in relation to spatial changes in stream water chemistry; (iii) In the upper catchment areas in Glen Muick, both small scale spatial changes in stream water chemistry and stream sediment chemistry were associated with changes in the underlying geology. In lower catchment areas, the usefulness of both techniques for indicating the position of geological boundaries, was limited; (iv) In a simulated laboratory weathering experiment, the four main bedrock lithologies in the Glen Muick catchments, were each shown to have a distinct chemical weathering signature, which correlated with chemical features in stream water; (v) In comparison to NE Scotland, lithological changes within catchments in Svalbard are unrelated to small scale downstream changes in stream water chemistry, due to the physical conditions which prevail in the high Arctic, such as permafrost and the abundance of suspended rock flour in stream water.
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Ren, Hong. "Electrochemical Modulation of the Sample Stream in Mass Spectrometry /." The Ohio State University, 1995. http://rave.ohiolink.edu/etdc/view?acc_num=osu1487928649987078.

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17

Laird, Mollie Kate. "Spatial and Temporal Changes in Stream Chemistry at Three Watersheds During High Discharge Episodes." Fogler Library, University of Maine, 2006. http://www.library.umaine.edu/theses/pdf/LairdMK2006.pdf.

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18

O'Brien, Christine. "Soil solution and streamwater chemistry in a small forested watershed." Thesis, McGill University, 1993. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=68234.

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The relationship between soils, soil water and stream chemistry was investigated for a first order stream in a small forested watershed in the southern Laurentians, Quebec. The study was restricted to near-stream processes, particularly how the chemistry of water leaving a hillslope influenced stream chemistry. For snowmelt, 1986, a number of naturally occurring chemical elements were used to separate stream flow into three subsurface flowpaths: groundwater, solum and upwelling flow. By quantifying upwelling flow, we introduced a new approach to identify solutions forced from the groundwater up through the solum before entering the channel. In upwelling flow, we found that dissolved silicon was reactive and total aluminum, monomeric aluminum, hydronium, magnesium and fluoride were non-reactive. For spring storms, 1992, we used an end member mixing approach to describe streamwater as a combination of chemically distinct solutions from different depths in the soil. Solutions were defined by concentrations of calcium, magnesium, sodium and dissolved silicon. The contributions of water from each soil depth were estimated using the variations in end member chemistry that were measured during the storms. Hydrological reconstructions of the events were possible and it was found that the contribution of water from each depth in podzols is related to the height of the water table in the near-stream soils.
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19

Zimmer, Margaret Ann. "An evaluation of surface water sources using spatial and temporal variations in stream chemistry in a headwater catchment." Oberlin College Honors Theses / OhioLINK, 2011. http://rave.ohiolink.edu/etdc/view?acc_num=oberlin1305995362.

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20

Ness, Lindsay Anne. "Solute deposition to an upland catchment : spatial patterns, temporal trends and links to stream water chemistry." Thesis, University of East Anglia, 2006. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.429683.

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21

Olson, John R. "The Influence of Geology and Other Environmental Factors on Stream Water Chemistry and Benthic Invertebrate Assemblages." DigitalCommons@USU, 2012. https://digitalcommons.usu.edu/etd/1327.

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Catchment geology is known to influence water chemistry, which can significantly affect both species composition and ecosystem processes in streams. However, current predictions of how stream water chemistry varies with geology are limited in both scope and precision, and we have not adequately tested the specific mechanisms by which water chemistry influences stream biota. My dissertation research goals were to (1) develop empirical models to predict natural base-flow water chemistry from catchment geology and other environmental factors, (2) extend these predictions to nutrients to establish more realistic criteria for evaluating water quality, and (3) test the hypothesis that catchment geology significantly influences the composition of stream invertebrate assemblages by restricting weak osmoregulators from streams with low total dissolved solids (TDS). To meet goal 1, I first mapped geologic chemical and physical influences by associating rock properties with geologic map units. I then used these maps and other environmental factors as predictors of electrical conductivity (EC, a measure of TDS), acid neutralization capacity, and calcium, magnesium, and sulfate concentrations. The models explained 58 – 92% of the variance in these five constituents. Rock chemistry was the best predictor of stream water chemistry, followed by temperature, precipitation and other factors. To meet goal 2, I developed empirical models predicting naturally occurring stream total nitrogen and total phosphorus concentrations. These models explained most of the spatial variation among sites in total nitrogen and phosphorus and produced better predictions than previous models. By determining upper prediction limits that incorporated model error, I demonstrated how predictions of nutrient concentrations could be used to set site-specific nutrient criteria and accounted for natural variation among sites better than regional criteria. To meet goal 3, I experimentally manipulated (high and low) EC in both stream-side and laboratory flowthrough microcosms and measured survival, growth, and emergence of 19 invertebrate taxa. Observed variation among taxa in survival between treatments predicted taxon EC optima estimated from field observations (r² = 0.60). Taxa with the greatest differences in survival between treatments also had the highest EC optima, indicating that the inability to persist in low EC likely restricts the distributions of some taxa.
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Savoie, Sylvain. "Contribution of soil solution chemistry to stream water quality in a small forested watershed during spring snowmelt." Thesis, McGill University, 1988. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=61857.

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23

Fung, Lai-kuen, and 馮麗娟. "An Investigation of the stream water chemistry in a small drainage basin in Shek Kong, Hong Kong." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2000. http://hub.hku.hk/bib/B22288077.

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Fung, Lai-kuen. "An Investigation of the stream water chemistry in a small drainage basin in Shek Kong, Hong Kong." Hong Kong : University of Hong Kong, 2000. http://sunzi.lib.hku.hk/hkuto/record.jsp?B22288077.

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25

Wellington, Brian Ishmael. "Controls on dissolved organic carbon at Hubbard Brook Experimental Forest and its effects on stream acid-base chemistry." Related electronic resource: Current Research at SU : database of SU dissertations, recent titles available full text, 2002. http://wwwlib.umi.com/cr/syr/main.

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26

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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27

Crandall, Trevor William. "Wildfire in the West: How Megafires and Storm Events Affect Stream Chemistry and Nutrient Dynamics in Semi-Arid Watersheds." BYU ScholarsArchive, 2020. https://scholarsarchive.byu.edu/etd/8886.

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Climate change is causing larger wildfires and more extreme precipitation events throughout the world. As these ecological disturbances increasingly coincide, they are altering lateral fluxes of sediment, organic matter, and nutrients. Increased lateral flux of nutrients could exacerbate eutrophication and associated harmful algal blooms, and increased sediment and organic matter flux could degrade the water supply. Here, we report the immediate stream chemistry response of watersheds in central Utah (USA) that were affected by a megafire followed by an extreme precipitation event in 2018. The wildfires burned throughout the summer of 2018 until the remnants of Hurricane Rosa released torrential rain on the still smoldering, 610-km2 burn scar. To assess how these multiple stressors affected lateral material fluxes, we collected daily to hourly water samples at 10 stream locations starting immediately before the storm event until three weeks after it finished. We quantified suspended sediment, solute and nutrient concentrations, water isotopes, and the concentration, optical properties, and reactivity of dissolved organic matter. For all land-use types, the wildfire caused substantial increases in sediment concentration and flux, increasing total suspended sediment by over 20-fold, attributable to the loss of stabilizing vegetation and increased runoff. Unexpectedly, dissolved organic carbon (DOC) was 2.1-fold higher in burned watersheds, despite the decrease in plant and soil organic matter, and this DOC was 1.3-fold more biodegradable and 2.0-fold more photodegradable than in unburned watersheds based on 28-day light and dark incubations. However, nitrogen and phosphorus concentrations were higher in watersheds with high anthropogenic influences, regardless of burn status. Likewise, direct human land use had a greater effect than wildfire on runoff response, with rapid storm water signals in urban and agricultural areas and a slow arrival of storm water in unburned areas without direct human influence. These findings indicate how megafires and intense rainfall fundamentally increase short-term sediment flux and alter organic matter concentration and characteristics, confirming previous research. These fluxes of degradable dissolved and particulate organic matter could exert short-term pressure on ecosystems already fragmented by human infrastructure. However, in contrast with previous research, which overwhelming focuses on burned-unburned comparisons in pristine watersheds, we found that the presence of urban and agricultural activity exerted a much greater influence on nutrient status than the wildfire. This novel finding suggests that reducing nutrient fluxes from urban and agricultural areas could make ecosystems more resilient to megafire and extreme precipitation events. Together with reducing anthropogenic climate change to reduce the frequency and extent of large wildfires, improving nutrient management should be a priority in semi-arid regions such as Utah.
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Chorover, Jon, Louis A. Derry, and William H. McDowell. "Concentration-Discharge Relations in the Critical Zone: Implications for Resolving Critical Zone Structure, Function, and Evolution." AMER GEOPHYSICAL UNION, 2017. http://hdl.handle.net/10150/626479.

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Critical zone science seeks to develop mechanistic theories that describe critical zone structure, function, and long-term evolution. One postulate is that hydrogeochemical controls on critical zone evolution can be inferred from solute discharges measured down-gradient of reactive flow paths. These flow paths have variable lengths, interfacial compositions, and residence times, and their mixing is reflected in concentration-discharge (C-Q) relations. Motivation for this special section originates from a U.S. Critical Zone Observatories workshop that was held at the University of New Hampshire, 20-22 July 2015. The workshop focused on resolving mechanistic CZ controls over surface water chemical dynamics across the full range of lithogenic (e.g., nonhydrolyzing and hydrolyzing cations and oxyanions) and bioactive solutes (e.g., organic and inorganic forms of C, N, P, and S), including dissolved and colloidal species that may cooccur for a given element. Papers submitted to this special section on concentration-discharge relations in the critical zone include those from authors who attended the workshop, as well as others who responded to the open solicitation. Submissions were invited that utilized information pertaining to internal, integrated catchment function (relations between hydrology, biogeochemistry, and landscape structure) to help illuminate controls on observed C-Q relations.
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Söderlund, Erik. "Snowmelt flushing of dissolved organic carbon (DOC) from urban boreal streams : A study of stream chemistry in Degernäsbäcken and Röbäcken." Thesis, Umeå universitet, Institutionen för ekologi, miljö och geovetenskap, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-163172.

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In boreal landscapes, large quantities of dissolved organic carbon (DOC) accumulated in soils are flushed into rivers and streams during snowmelt. These inputs supply energy to aquatic microbes, affect pH, and can promote the transportation of metals to streams and rivers. However, during the spring flood, changes in stream DOC are influenced by the structure of the catchment (e.g., forest vs. wetland cover), where different solutes are stored in soils, and snowmelt hydrology. While these mechanisms have been studied extensively in ‘pristine’ boreal landscapes, the influence of agricultural and urban land use on DOC flushing during snowmelt is poorly understood in this region. To understand these influences, I measured DOC, along with pH, conductivity, and discharge, during snowmelt at three boreal streams draining agricultural and urban lands.  I analyzed chemical patterns using discharge-concentration curves that reveal whether solutes are stable (chemostatic) or change (chemodynamic) during floods. Similar to observations made in forested catchments elsewhere, DOC was chemodynamic at all sites, increasing with discharge; however, two sites did show dilution at the very highest flows. pH declined with discharge at one site, but did not change at the other two. Electrical conductivity declined (was diluted) with increasing discharge for all sites, coinciding with previous studies. These results indicate that the majority of these chemical patterns in boreal streams influenced by agriculture and urban land use are chemodynamic, either increasing or decreasing in concentration with discharge during snowmelt. However more studies are needed to further clarify if patterns human-modified catchments are consistent with models based on boreal forested catchments.
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Norström, Sara H. "Soil and stream water chemistry in a boreal catchment - interactions, influences of dissolved organic matter and effects of wood ash application." Doctoral thesis, Mittuniversitetet, Institutionen för naturvetenskap, teknik och matematik, 2010. http://urn.kb.se/resolve?urn=urn:nbn:se:miun:diva-12998.

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Two small bordering catchments in Bispgården, Central Sweden, wereinvestigated in regard to soil solution and stream water chemistry during the frostfree seasons of 2003-2007. Both catchments were drained by first order streams,Fanbergsbäcken and Gråbergsbäcken, and in Fanbergsbäckens catchment anextensive investigation of the soil and soil solution chemistry was conducted bylysimeter and centrifugation sampling. The area of intensive soil solutioninvestigation was situated in a slope towards a stream incorporating a rechargearea, with podzolic soil, and a discharge area close to the stream with an arenosolsoil. Samples were continuously taken in both the recharge- and the discharge areaof the slope, and stream water was sampled in the streams of both catchments. Themain variables of interest of the study were the interactions, the influence ofdissolved organic carbon and the effects of wood ash application to soil solutionand stream water.The natural variations and the interactions between soil solution and streamwater were monitored during 2003-2004. In soil solution, most of the investigatedsubstances tended to increase during the growing season, due to weathering andmicrobial degradation of biota. Ca, Mg, Al and Fe were highly associated todissolved organic carbon (DOC) throughout the catchment. The low molecularfraction of DOC seemed to have a higher impact on the soil processes in therecharge area, while high molecular DOC was more important for transport ofcations in the discharge area and the stream water.The concentration of different substances in the two streams differedsignificantly, even though the catchments were similar in size, shape andforestation. The seasonal patterns of most of the substances measured weresignificantly correlated between the streams, however. Cations and pH correlatedwell with DOC and flow. The flow pattern driven by precipitation seems to be thedriver of the stream water chemistry.Wood ash was applied at a dosage of 3 ton/ha to one of the catchments in theautumn of 2004, to investigate the initial effects on the soil solution- and streamwater chemistry. WAA is recommended by the Swedish Forest Agency tocounteract acidification in soil and runoff that may be caused by an intensivebiomass harvesting. The impact of the WAA was studied during 2005-2006.Compared to the control temporarily higher concentrations of K, Ca and SO4 wereobserved in the soil solution of the ashed area. In the stream water the effects of theWAA were easier to distinguish due to higher sampling frequency. The strongesteffect was seen for K, but increases in the stream water were also noted for DOC,Ca, Mg, Si, Cl and malonate. No increase in pH could be statistically verifiedhowever, and overall the initial effects of the WAA seem mild.
Två angränsande avrinningsområden i Bispgården i centrala Sverigeundersöktes under den snöfria säsongen 2003-2006. Båda avrinningsområdenadränerades av första ordningens bäckar och i det ena, Fanbergsbäckensavrinningsområde, gjordes en omfattande undersökning av mark och markvattenkemin.Markvatten provtogs genom centrifugering och med lysimetrar.Provtagningen gjordes i inströmningsområdet där jordmånen var en typiskpodzol samt närmare bäcken, i utströmningsområdet, där jordmånen var enarenosol. Bäckvatten provtogs i båda avrinningsområdena. Interaktioner mellanmark, markvatten och bäckvatten undersöktes med särskilt fokus på inverkan avorganiskt kol samt påverkan av askåterföring.De naturliga variationerna i markkemin samt interaktionerna mellan mark- ochbäck vatten undersöktes 2003-2004. I markvatten ökade merparten av de studeradeämnena under provtagningssäsongen beroende av ökad vittring och recirkulationav biota och fallförna. Ca, Al och Fe var i stor utsträckning associerade till löstorganiskt kol (DOC). Den lågmolekylära fraktionen av DOC hade en störreinverkan på markprocesserna i inströmningsområdet, medan den högmolekyläradelen var viktigare för transport av katjoner i utströmningsområdet samt ibäckvattnet.Koncentrationsnivåerna av olika substanser i bäckarna uppvisade skillnadertrots avrinningsområdenas yttre likheter med avseende på storlek, form ochbeskogning. Trots de kvantitativa skillnaderna erhölls emellertid liknandesäsongsvariationer i koncentrationerna, vilket indikerade att kemin i huvudsakstyrdes av mängden DOC som i sin tur berodde av avrinningen som drevs avnederbörden. Höga halter av Ca, Mg, Al och Fe återfanns associerade tillhögmolekylärt DOC i bäckvattnet i en utsträckning som inte rapporterats tidigare.På hösten 2004 spreds 3 ton aska/ha till Fanbergsbäckens avrinningsområde föratt undersöka de initiala effekterna på mark- och bäckvatten kemin. Askåterföringbör ske minst en gång per omloppstid vid helträdsavverkning, i enlighet medSkogsstyrelsens rekommendationer, främst för att motverka försurning i mark ochavrinnande vatten som antas uppstå vid intensivt uttag av biomassa. De initialaeffekterna av askåterföringen på mark- och bäckvattnets kemi studerades under2005-2006 och Gråbergsbäcken kunde användas som obehandlad kontroll vidundersökning av vattenkemin i Fanbergsbäcken. I undersökningen av markvattenviåterfanns stora säsongsvariationer, vilket gjorde det svårt att urskilja eventuellaeffekter av askåterföringen. Tillfälligt högre värden av K, Ca och SO4 återfannsdock i det askade området i jämförelse med kontrollområdet. På grund av högreprovtagningsfrekvens i bäckvattnet var det lättare att påvisa förändringar ibäckvatten kemin. Framförallt märktes en signifikant ökning av K jämfört medkontrollbäcken. Sådana ökningar, om än inte lika markanta återfanns också förDOC, Ca, Mg, Si, Cl och malonat. En tendens till ökat pH kunde observeras, mendenna kunde inte verifieras statistiskt. De initiala effekterna av askåterföringen varsåledes till synes milda, och den eftertraktade pH-effekten erhölls ej i dennaundersökning.
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31

Shaw, Meaghan Elizabeth. "Concentration-discharge behavior of contaminants in a stream impacted by acid mine drainage." Kent State University / OhioLINK, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=kent1529320351379744.

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32

Schleich, Katharine L. "Geochemical Modeling of Processes Affecting Water and Sediment Chemistry and their Relationship to Biological Recovery in an Acid Mine Drainage Remediated Stream." Ohio University / OhioLINK, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1399477158.

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33

Oteng-Attakora, George. "Mechanisms of heat and mass transfer to and from single drops freely-suspended in an air stream." Thesis, Aston University, 1995. http://publications.aston.ac.uk/9686/.

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A specially-designed vertical wind tunnel was used to freely suspend individual liquid drops of 5 mm initial diameter to investigate drop dynamics, terminal velocity and heat and mass transfer rates. Droplets of distilled, de-ionised water, n-propanol, iso-butanol, monoethanolamine and heptane were studied over a temperature range of 50oC to 82oC. The effects of substances that may provide drop surface rigidity (e.g. surface active agents, binders and polymers) on mass transfer rates were investigated by doping distilled de-ionised water drops with sodium di-octyl sulfo-succinate surfactant. Mass transfer rates decreased with reduced drop oscillation as a result of surfactant addition, confirming the importance of droplet surface instability. Rigid naphthalene spheres and drops which formed a skin were also studied; the results confirmed the reduced transfer rates in the absence of drop fluidity. Following consideration of fundamental drop dynamics in air and experimental results from this study, a novel dimensionless group, the Oteng-Attakora, (OT), number was included in the mass transfer equation to account for droplet surface behaviour and for prediction of heat and mass transfer rates from single drops which exhibit surface instability at Re>=500. The OT number and the modified mass transfer equation are respectively: OT=(ava2/d).de1.5(d/) Sh = 2 + 0.02OT0.15Re0.88Sc0.33 Under all conditions drop terminal velocity increased linearly with the square root of drop diameter and the drag coefficient was 1. The data were correlated with a modified equation by Finlay as follows: CD=0.237.((Re/P0.13)1.55(1/We.P0.13) The relevance of the new model to practical evaporative spray processes is discussed.
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34

Diehl, Melinda S. "Using Stream Chemistry to Evaluate Experimental Acidification and Natural Recovery in the Paired Catchments at the Bear Brook Watershed in Maine (1989-2003)." Fogler Library, University of Maine, 2006. http://www.library.umaine.edu/theses/pdf/DiehlMS2006.pdf.

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35

Haught, Samantha. "Significance of the hyporheic zone and runoff on the water chemistry of the stream water in a small tributary of the Olentangy River." The Ohio State University, 2003. http://rave.ohiolink.edu/etdc/view?acc_num=osu1413360067.

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36

Schweitzer, Na'ama. "Greening the Streets: A Comparison of Sustainable Stormwater Management in Portland, Oregon and Los Angeles, California." Scholarship @ Claremont, 2013. http://scholarship.claremont.edu/pomona_theses/85.

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Stormwater runoff is one of the main sources of pollution for urban waterways. Stormwater has traditionally been managed through concrete-based storm drainage systems, but the past twenty years have introduced an alternative in the form of green infrastructure. Green infrastructure for stormwater management involves the use of low impact development (LID), often vegetated facilities to mimic natural hydrologic systems that capture and allow infiltration of rainwater where it falls and from impervious surfaces upstream, before entering the drainage system. Portland, Oregon and Los Angeles, California have adopted green infrastructure into their stormwater management plans. For this project, bioswales, a form of vegetated LID facility, were tested in each city to determine their pollutant retention capabilities. Results from Portland show that bioswales filter out heavy metals effectively, and results from Los Angeles show that bioswales accumulate heavy metals in the soil over the course of the year (also due to filtering out metals from the stormwater). These results raise the question of whether accumulation can reach dangerous levels or saturate the soil with pollutants so that removal efficiency is diminished, indicating a need for further monitoring. However, the success of bioswales up to this point is encouraging and indicates that this method should continue to be employed.
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37

Berg, Ivan. "Headwaters and forestry : Effect of riparian buffers on stream physiochemical properties." Thesis, Umeå universitet, Institutionen för ekologi, miljö och geovetenskap, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-163017.

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Forest management practices usually preserves riparian buffers along watercourses in order to protect stream water from physical, chemical and ecological changes caused by clear-cutting. The purpose of this thesis was to investigate whether there is a relationship between the size of the riparian buffer zone along small streams, i.e., headwaters, and a number of physical and chemical attributes of these streams. Twelve headwaters in the Västerbotten county and twelve in Jönköpings county were investigated. These headwaters had a range of buffer widths from “No buffer” (no trees left), Thin buffer” (< 5 m wide), to “Moderate buffer” (>5 m wide) and “Reference” (no harvest) streams were also included. Tested physical and chemical conditions were light in the riparian zone, air and water temperature, stream bed cover and water chemistry. Buffer width had a significant effect on reducing light levels and temperature in the riparian zone; a buffer width over 13 m on each side of the stream was needed to maintain light and air temperature as in reference conditions. Regarding water temperature, increasing sedimentation and water quality, no significant reducing effect of increasing riparian buffer width was found.
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Butler, Steven Kyle. "An Introductory Study of Solid Materials for Capture and Catalysis of Waste Stream Chemicals." BYU ScholarsArchive, 2018. https://scholarsarchive.byu.edu/etd/6845.

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Heterogeneous catalysts are key materials in research and industry. Herein we study two materials in different stages of development toward being applied as heterogeneous catalysts. First, MoO3SnO2 was synthesized and studied as a catalytic system similar to Sn-beta zeolites. While the Mo-based catalyst did not show similar activity to Sn-beta, it did show interesting reactivity in activating carbonyls and oxidizing organic substrates. Second, a method was developed for grafting amines onto carboxylic acid functionalized carbon nanotubes for CO2 capture. The method was successful for grafting monomer ethylamine groups onto CNT and can be further developed to allow for polymeric amine groups to be grafted.
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39

Linda, Engström. "Effects of forestry on stream water chemistry during autumn : A before and after comparison between a reference and two streams with clear-cut watershed areas." Thesis, Umeå universitet, Institutionen för ekologi, miljö och geovetenskap, 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-83124.

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Forestry is a large-scale business in many countries, and in northern Sweden a large portion of the Boreal forests is cut. Yet very few studies have investigated the impacts of forestry on the vast number of receiving stream waters. This study has therefore investigated the impacts of forestry, through clear-cutting, on stream water chemistry during autumn conditions in northern Sweden. The study compares the parameters water height, absorbance, dissolved organic carbon, total dissolved nitrogen and total phosphorus in two inlet streams in recently deforested sites, <1 year ago, and an undisturbed reference inlet stream. The disturbed inlet streams are compared to the reference inlet stream the year before and after clear-cutting. This study shows that during a 15- day period from late August to the beginning of September, water height was increased in both disturbed inlet streams, indicative of a higher run-off post-harvest. Absorbance showed a large decrease post-harvest in the disturbed inlet streams. Total dissolved nitrogen and total phosphorus concentrations decreased slightly after clear-cut in both disturbed inlet streams. The effect was probably larger for phosphorus, since the seasonal variation in the reference was larger in 2013. DOC concentrations increased slightly in one of the disturbed inlet streams in 2013, but decreased slightly in the other disturbed inlet stream. The increased run-off was therefore not followed by a higher DOC and nutrient leakage. Results suggest that during a short period in the autumn, harvest does not seem to lead to increased DOC and nutrient losses to receiving stream waters.
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Stenlund, Emma. "Effects of land use on northern boreal streams : a study of stream nutrient patterns in Röbäcksdalen, Umeå." Thesis, Umeå universitet, Institutionen för ekologi, miljö och geovetenskap, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-171876.

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Nutrient loading to aquatic and marine ecosystems is a topic of interest, especially as the human population continues to grow and land use changes. Here, I examined the seasonal variability and relative amounts of different forms of nitrogen (N) and phosphorous (P) from four sites at Röbäcksdalen (Umeå, Västerbotten), an area influenced by both agriculture and partial urbanization. In addition, I studied how nutrient concentration varied with discharge during snowmelt. Overall, the results show that the seasonality of nutrient concentration did not differ drastically from what is expected in more pristine boreal catchments. However, the concentrations of dissolved inorganic N (DIN) and phosphate (PO4) were elevated. Land use activities in Röbäcksdalen also appear to be influencing inorganic N inputs to streams to a greater degree than inputs of inorganic P. Comparisons with more pristine boreal streams also reveal a fundamental change in the composition of the stream N pool, with greater dominance of DIN within the catchment. This pattern is likely due to inputs of nutrients in excess of biotic demand. Lastly, the results of the concentration-discharge analysis from Röbäcksdalen indicate that hydrological forcing rather than soil processes control the supply of nutrients to these streams during snowmelt. With concentrations being high, this also indicates that a considerable increase in the flux of nutrients from the area is expected with increased discharge.
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Carter, Shaun A. "Geochemical analysis of the Powder River, Wyoming/Montana and an assessment of the impacts of coalbed natural gas co-produced water." Laramie, Wyo. : University of Wyoming, 2008. http://proquest.umi.com/pqdweb?did=1663116711&sid=1&Fmt=2&clientId=18949&RQT=309&VName=PQD.

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42

Risley, Elizabeth Ellen. "Relationships among land use, geomorphology, local habitat and aquatic macroinvertebrate assemblages in agricultural headwater stream systems." Connect to resource, 2006. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=osu1225828275.

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43

Klaus, Jaclyn Elizabeth. "In situ measurement of mercury ecotoxicological effects on stream periphyton in southwest Ohio." Wright State University / OhioLINK, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=wright1409918494.

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44

Porter, Courtney. "Solute Inputs to Soil and Stream Waters in a Seasonally Snow-Covered Mountain Catchment Determined Using Ge/Si, ⁸⁷SR/⁸⁶SR and Major Ion Chemistry: Valles Caldera, New Mexico." Thesis, The University of Arizona, 2012. http://hdl.handle.net/10150/265377.

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Weathering releases lithogenic elements to soil and stream waters that support life in catchment ecosystems. Seasonal and inter-annual variations in hydrologic conditions change subsurface flowpaths, modifying the influence of weathering on stream waters. This study, over two climatically variable years, determined seasonal and inter-annual changes in solute sources to streams using a multi-tracer approach including major cations, strontium isotopes, germanium (Ge)/silica ratios, carbon species, and trace metals. Stream water cations display constant concentrations although discharge response was highly variable, suggesting that there is a consistent subsurface water supply. However, Sr isotope ratios, and concentrations of Ge, Fe, Al, and dissolved organic carbon, which originate from shallow soil waters, increase with the hydrograph during a wet winter snowmelt. This indicates that during a year with a thick snowpack, stream waters contain components of both shallow soilwater and groundwater during snowmelt, whereas during all other times groundwater contributes predominantly to the stream.
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45

Slye, Jaime L. "Relationships of Benthic Macroinvertebrate Community Structure with Land-use, Habitat, In-stream Water Chemistry, Depositional Sediment Biofilm Fatty Acids, and Surfactants in the Effluent Dominated Texas Trinity River." Thesis, University of North Texas, 2013. https://digital.library.unt.edu/ark:/67531/metadc407738/.

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The Trinity River is an urbanized, effluent-dominated river, and is heavily relied upon for drinking water. The benthic macroinvertebrate community has been monitored for over 20 years, with the focus of this dissertation on three studies (1987-88, 2005, and 2011). Water quality improvement following dechlorination resulted in increased benthic metrics. Overall habitat quality, in-stream cover, surface water total organic carbon, sediment total organic carbon, near-field urban land-use, near-field forested land-use, surface water surfactant toxic units, and depositional sediment biofilm fatty acids all have statistically significant relationships with benthic macroinvertebrate metrics. These relationships are better defined with increased taxonomic resolution at the genus/species level for all benthic taxa, including Chironomidae and Oligochaeta. It is recommend that benthic identifications for state and city water quality assessments be done at the genus/species level. A novel method for quantifying depositional sediment biofilm fatty acids has been produced and tested in this dissertation. Benthic metrics are directly related to fatty acid profiles, with several essential fatty acids found only at upstream sites.
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46

Miedema, Natalie Margaret. "Non-anthropogenic sources of carbon dioxide in the Glowworm Cave, Waitomo." The University of Waikato, 2009. http://hdl.handle.net/10289/2781.

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The Waitomo Caves attract approximately 500 000 tourists each year. A requirement of tourist cave management is that the partial pressure of carbon dioxide (PCO₂) is kept below levels that are: hazardous to the health of visitors, hazardous to the glowworms and other natural inhabitants, or potentially corrosive to speleothems. For the Glowworm Cave at Waitomo, the maximum permissible PCO₂ level is 2400 ppm. When exceeded, the tourist operators are required to close the cave. Ten years of monitoring data at the Glowworm Cave was analysed. Most of the variation in PCO₂ could be attributed to CO₂ respired by tourists, and the mixing of cave air with lower PCO₂ outside air. Occasionally, there were periods with high PCO₂ levels while the cave was closed to tourists. The main objective of this study was to investigate the potential role of the Waitomo Stream in contributing CO₂ to the Glowworm Cave atmosphere. Analysis of ten years of Glowworm Cave monitoring data showed that the 2400 ppm PCO₂ limit was, on average, exceeded five times each year, with a total of 48 events between 1998 and 2007. Of the PCO₂ limit exceedences, approximately 31% of events were largely driven by high tourist numbers; 27% of PCO₂ limit exceedences were mainly driven by increased discharge, rainfall, and/or a low temperature gradient between the cave and outside air, whilst 29% of the PCO₂ limit exceedences were due to a combination of tourists and increased discharge, rainfall, and/or a low temperature gradient. The remaining 13% of exceedences were unexplained by tourists or the factors investigated. It may be that the unexplained exceedences were due to the night time closure of the cave door, restricting air exchange. The PCO₂ of the Waitomo Stream was measured by equilibrating air with the streamwater within a closed loop. The air was passed continuously through an infrared gas analyser (IRGA). The streamwater PCO₂ typically ranged between 600 - 1200 ppm. Fluctuations in the PCO₂ of the Waitomo Stream coincided with PCO₂ fluctuations in the Glowworm Cave air, and under most conditions, the stream probably acted as a sink for cave air CO₂. However, following rainfall events, the stream PCO₂ increased, exceeding cave air PCO₂, thus acting as a source of CO₂ to the cave air. High stream PCO₂ often occurred at times when air flow through the cave was restricted, e.g. when the temperature gradient between the cave air and outside air was low, or stream levels were high, thus limiting air movement. The combination of high stream PCO₂ and a low temperature gradient increased the likelihood of high cave air PCO₂. Dripwater was measured to determine whether an increase in dripwater PCO₂ occurred in response to rainfall events. When rainfall events resulted in increased discharge, the dripwater PCO₂ sometimes increased (occasionally exceeding 5000 ppm), however the pattern was not consistent. The chemistry of the Waitomo and Okohua (Ruakuri) Streams was monitored with daily samples collected and analysed for major ions: HCO₃ -, Ca²⁺, Na⁺ and Mg²⁺, and δ¹³C stable isotope. The HCO₃ -, Ca²⁺, Na⁺ and Mg²⁺ concentrations in the streamwater decreased with increased discharge, presumably due to dilution. Increased discharge following rainfall events correlated with increasing PCO₂ in the Waitomo Stream, suggesting that soil atmosphere CO₂ dissolved in soil waters, and carried to the stream by saturated flow, was responsible for the streamwater PCO₂ increase. Ca in the stream showed both an increase and a decrease with respect to rainfall. Increased Ca in the stream occurred at times when the discharged waters were coming from the phreatic zone, and thus sufficient time had lapsed for CO₂ in the discharge waters to react with the limestone (carbonate dissolution reaction). Decreased Ca occurred when the infiltration and percolation of rainwater was rapid, and thus the streamwater was characterised by a higher PCO₂ and a lower Ca concentration, as insufficient time had lapsed for the discharge waters to equilibrate with the limestone. Increased negativity in the δ¹³C of the Waitomo and Ruakuri Streams coincided with increased discharge. During summer low flow, the δ¹³C of Waitomo Stream waters was -11.3‰, whereas during high stream discharge events, the δ¹³C dropped to -12 - -14‰. The δ¹³C of limestone is 0‰, the atmosphere is -7‰, and the soil atmosphere is reported to be about -24‰, thus the decrease in δ¹³C during high flow events supports the contention that soil atmosphere CO₂ is a likely source of the increased CO₂ in flood waters.
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47

Baumann, Elise, and Hanna Berglund. "Dynamics of streamflow and stream chemistry in a Swiss pre-Alpine headwater catchment : A fine scale investigation of flow occurrence and electrical conductivity in the temporary streams in the lower Studibach catchment." Thesis, Uppsala universitet, Luft-, vatten- och landskapslära, 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-434637.

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Temporary streams and their dynamics have often been largely overseen in hydrological research and there is relatively little knowledge about how the occurrence of flow in these streams varies temporally and spatially. Temporary streams are important from a hydro- logical perspective because they affect water quantity and quality in downstream peren- nial reaches, and from an ecological perspective because they provide habitat to unique species. In order to gain knowledge about these important streams, this maser thesis was conducted, within the Msc program in Water and Environmental Engineering at Uppsala University and the Swedish University of Agricultural Sciences, in collaboration with the Hydrology and Climate group at the University of Zurich. In this study, the temporal and spatial variation of the temporary streams in a small pre-Alpine catchment in Switzerland were investigated, both in terms of the presence of flowing water and stream chemistry. The 20 ha Studibach catchment is typical for the pre-Alpine area, with frequent precipi- tation. The streams in the lower part of the Studibach catchment were mapped in the field during September 2020. The temporal and spatial variations of the presence of flow and stream chemistry within the stream network was investigated in September and October 2020 during varying weather conditions. During ten field campaigns the flow state of the streams was classified and the Electrical Conductivity (EC) of the streams was mea- sured approximately every 20 meter. The findings from the field campaigns were related to topographic indices, in particular the Topographic Wetness Index (TWI) and Upslope Accumulated Area (A), in order to see how topography influenced the presence of stream- flow and stream EC. The results show a high temporal and spatial variation in both stream chemistry and streamflow. The active network length expanded by a factor of two in re- sponse to precipitation events. The stream EC also had a large spatial variation, and the streams in the southeast part of the catchment had a higher EC than the other streams. This spatial variation is expected to reflect the large variability in groundwater EC within the catchment. The spatial variation of the streamflow demonstrated a difference between the north-middle and the south part of the catchment, where the south part responded quicker to events and drained and retracted faster after the event. The findings also indicate that topographic indices can predict the occurrence of flow in the stream network, with sites with higher topographic index values having a higher probability of flowing water in the stream. Topography also influences the stream chemistry. The variation in stream chem- istry was smaller for sites with higher values for the topographic indices, something that can be explained by the Representative Elementary Area (REA) concept, because sites with higher topographic index values are located further downstream and water at these locations is a mixture of the smaller streams that feed these streams.
Temporära bäckar och dess dynamik har länge varit förbisedda inom hydrologisk forskn- ing, och en djupgående kunskap rörande temporära och rumsliga variationer saknas. Tem- porära bäckar är viktiga utifrån ett hydrologisk perspektiv eftersom de påverkar både kvantitet och kvalitet på vattnet nedströms, och från ett ekologiskt perspektiv eftersom de bidrar med habitat till unika arter. Detta examensarbete har genomförts för att öka kunskapen kring dynamiken i dessa temporära nätverk. Examensarbetet genomfördes inom Civilingenjörsprogrammet i Miljö och Vattenteknik vid Uppsala Universitet och Sveriges Lantbruksuniversitet, i ett samarbete med Hydrologi- och Klimatgruppen vid University of Zurich. Studien har undersökt temporära och rumsliga variationer i ett tem- porärt bäcknätverk med avseende på flöden och kemin i vattnet, i ett mindre pre-alpint avrinningsområde i centrala Schweiz. Bäckarna i den nedre delen av avrinningsområdet Studibach karterades i fält för hand med karta och kompass under september 2020. Avrin- ningsområdet är på 20 ha och räknas som typiskt för ett pre-Alpint område, med frekvent nederbörd. Tio fältkampanjer genomfördes där temporära och rumsliga variationer un- dersöktes genom klassificering av flöden och mätningar av Elektrisk Konduktivitet (EC) i bäckarna ungefär var 20e meter, under september och oktober 2020 i varierande väder- förhållanden. Resultaten från fältkampanjerna relaterades till de topografiska indexen Topographic Wetness Index (TWI) och Upslope Accumulated Area (A) för att undersöka hur topografin påverkar flöden och bäckkemin. Studien kom fram till att bäckarna i den nedre delen av Studibach visar både en temporär och en rumslig variation för både flöde och bäckkemi. De aktiva bäckarna i nätverket visade på en expansion med en faktor två som svar på nederbörd. En rumslig variation för flödet påträffades även mellan den södra och nord-centrala delen av nätverket där den södra svarade snabbare mot event och även drogs ihop snabbare. Kemin i bäckvattnet visade på en stor rumslig variation, med högt EC i den sydöstra delen av avrinningsområdet, vilket förmodas bero på den stora rumsliga variationen av EC i grundvattnet. Resultaten visar även på att topografiska index kan till viss del förutspå flöden i bäckarna, där platser med högre topografiska index har högre sannolikhet att det flödar i bäcken. Topografin påverkar även bäckkemin. Variationen i bäckkemin var mindre för platser med högre topografiska index, vilket kan förklaras med Representative Elementary Area (REA) konceptet, eftersom platser med högre to- pogragiska index värden återfinns längre nedströms och vattnet på dessa platser är en blandning av de mindre bäckarna som tillför vattnet till de större.
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48

Yazbek, Lindsey Danese. "Hydrogeochemical Factors Influencing Metal Transport and Transformation in a Stream Impaired by Acid Mine Drainage." Kent State University / OhioLINK, 2019. http://rave.ohiolink.edu/etdc/view?acc_num=kent1564478839556002.

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49

Temnerud, Johan. "Spatial Variation of Dissolved Organic Carbon along Streams in Swedish Boreal Catchments." Doctoral thesis, Örebro University, Institutionen för naturvetenskap Department of Natural Sciences, 2005. http://urn.kb.se/resolve?urn=urn:nbn:se:oru:diva-116.

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Abstract:

Denna avhandling behandlar den småskaliga rumsliga variationen av löst organiskt kol (DOC, engelsk term: dissolved organic carbon), dess koncentration, masstransport och karaktär, i bäckar inom två barrskogsbeklädda avrinningsområden (delavrinningsområden 0,01-78 km²). Provtagningen gjordes uppströms och nedströms varje bäckförgrening under sommarbasflöde. Koncentrationen av DOC varierade inom en tiopotens (4-66 mg/l), liksom flera andra kemiska parametrar. Vid riksinventeringen av vattendrag för 2000 i norra Sverige noterades en snarlik spännvidd. Enligt Naturvårdverkets bedömningsgrunder för sjöar och vattendrag återfanns alla tillståndsklasser för DOC och pH, samt mänsklig påverkansgrad till försurningen inom de två studerade områdena. Den specifika avrinningen (flöde per areaenhet) varierade kraftigt i källflödena och inverkade på deras bidrag till kemin nedströms. Vattenkemin och specifika avrinningen var stabila i delavrinningsområden större än 15 km². Det kan vara nödvändigt att provta så stora områden om generella värden för landskapet önskas, men källflödenas kemi kommer då inte att kunna karakteriseras, ehuru källflödena utgör den största delen av bäcksträckan och det akvatiska ekosystemet.

Nedströms är DOC-koncentrationen, och många andra kemiska parametrar, lika med summan av bidragen från källflödena och nedströms utspädning av inflödande vatten. Tillkommer gör processer inom bäcken och vattnets utbyte med botten/grundvatten (den hyporheiska zonen), men även DOC-förluster/transformationer vid vissa bäckförgreningar och sjöar. Ovanstående resonemang förklarade bäckvattenkemins minskande variation och vanligen lägre DOC-koncentrationer nedströms i ett landskapsperspektiv. Längs bäcksträckorna observerades ingen generell minskning av DOC-koncentration eller ändring av dess karaktär. Skillnaden i DOC-koncentration och relaterade parametrar mellan källflöden och nedströms styrdes i hög grad av vilka landskapselement (myrar, sjöar och skogsmark) som vattnet hade passerat innan det hamnade i bäckarna, samt samspelseffekter med den specifik avrinningen och platserna med DOC-förlust. Prognoser med multivariata modeller baserade på kartinformation testades men kunde inte förutsäga det rumsliga mönstret eller DOC-koncentrationen med erforderlig precision.

Lämpliga rutiner inom miljöövervakningen för att övervaka den rumsliga variationen av kemin i ytvatten saknas alltjämt. Vid planering av terrestra och akvatiska skötselåtgärder bör man beakta bäckvattnets naturliga kemiska variation.


This thesis quantifies the small-scale spatial variation of dissolved organic carbon (DOC) concentrations, fluxes and character in two boreal catchments (subcatchments 0.01-78 km²) using ”snapshots” of summer base flow where samples were taken upstream and downstream from every node in the stream network. An order of magnitude variation was found in DOC-concentrations, and many other chemical parameters. The range was similar to that found in all of northern Sweden by the national stream survey in 2000. According to the official assessment tools used in Sweden, the entire range of environmental status for DOC, pH and human acidification influence existed within these two study catchments. A large variability in specific discharge had a major impact on the contribution of headwaters to downstream chemistry. The water chemistry parameters were relatively stable at catchment areas greater than 15 km². Sampling at that scale may be adequate if generalised values for the landscape are desired. However the chemistry of headwaters, where much of the stream length and aquatic ecosystem is found would not be characterized.

Downstream DOC-concentrations, as well as many other chemical parameters, are the sum of headwater inputs, in combination with progressive downstream dilution by inflowing water with its own DOC-concentration and character. Superimposed upon this are in-stream and hyporheic processes, as well as discrete loci of DOC loss/transformation at lakes and stream junctions. At the landscape scale, this results in a decreased downstream variation in stream water chemistry and often, but not necessarily, lower average DOC-concentrations. Along stream reaches there was not a loss of DOC-concentration or a consistent change in character. While the importance of in-stream/hyporheic processes that consistently alter DOC-concentrations along the channel network cannot be ruled out, the differences between headwater and downstream DOC-concentrations and related parameters depend largely on the mosaic of landscape elements (mires, lakes and forest soil) contributing water to the channel network, combined with patterns of specific discharge and discrete loci of DOC loss. Assessment would be facilitated by map information that could predict spatial patterns. Multivariate models using maps, however, did not give satisfactory predictions.

Appropriate procedures for dealing with spatial variation in the environmental assessment of surface waters are not yet established. An awareness of stream water chemistry’s natural spatial variability should be considered when planning aquatic and terrestrial management.

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50

Myrstener, Maria. "Konduktivitet i vattendrag som indikator på sura sulfatjordar." Thesis, Umeå universitet, Institutionen för ekologi, miljö och geovetenskap, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-61632.

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Increasing attention is being given to acid sulphate soils wherever they occur. The problems that leaching sulphate soils gives with significant lowerings of pH and mobilization of heavy metals influence large spectra of our society from fisheries to agriculture to construction. Mapping these soils is consequently of great importance and the methods of doing this is very much lacking in function and precision. This study was therefore carried out to investigate whether conductivity in running water can be used as a simple instrument to identify acid sulphate soils in the catchment. 31 coastal streams in the county of Västerbotten were analyzed for different catchment properties such as occurence of marine sediments and basic water chemistry including conductivity and sulphate. Sulphate proved to be the dominant factor controling conductivity in most streams, constituting up to 90 % of the anions. The results also showed that the concentrations of sulphate correlated to 67 % with marine sediments in the catchment. Where conductivity values exceeded 90 µS/cm the influence of acid sulphate soils could be determined for certain. The major conclusion drawn from this study is that high conductivity values serves as a reliable indicator of leaching acid sulphate soils whereas lower values can not exclude them.
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