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1
Sgouridis, Fotis. "Nitrate attenuation in a restored river floodplain system : River Cole (Oxfordshire, UK)." Thesis, Queen Mary, University of London, 2010. http://qmro.qmul.ac.uk/xmlui/handle/123456789/590.
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Restoring river-floodplain connectivity has been proposed as an alternative management measure for natural flood defence through the temporary storage of floodwaters and the attenuation of flood peaks downstream. Whilst several studies have documented the associated ecological and landscape amenity values of such hydrological measures, the water quality benefits to the adjacent water bodies have been inadequately studied. To date, the focus of scientific research and natural resource management has been on the role of riparian buffer zones for the alleviation of agricultural diffuse nitrate pollution. This research investigated the potential for nitrate attenuation in a restored riverfloodplain system, the River Cole (Coleshill, England), with the aim of informing future restoration schemes of the best management practices for enhanced nitrate removal. Following restoration, the increased river-floodplain connectivity has encouraged overbank flooding of the different land use zones throughout the year. The flood pulse supplies the floodplain soil with river water nitrate and creates the necessary anaerobic conditions for the effective removal of nitrate via heterotrophic denitrification, while organic carbon is supplied mainly through the traditional land use management practices of grazing and mowing. The conservation of nitrogen via DNRA is of minimal importance in this lowland agricultural catchment setting, mainly due to the nonlimiting nitrate supply from the surrounding agricultural land but also the intermittent saturation regime that restricts the low redox conditions to the low elevation riparian areas. This presents the added benefit of restricting methane emission to the more frequently waterlogged riparian soils, while denitrification is effective across the whole floodplain area. Additionally, more than 90% of nitrate removal occurs in the top 30 cm of the soil during the flood, while the role of subsurface denitrification is restricted by the limited availability of organic carbon and nitrate. Based on these findings, this study demonstrates that, for similar catchments, the nitrate removal capacity of a floodplain can be assessed by the denitrification capacity of the surface soil. The assessment of the denitrification capacity can be undertaken inexpensively using a simple empirical model that requires a single microbial denitrification potential measurement, and a seasonal or monthly record of soil nitrate content, soil moisture, and temperature. Assessments can be undertaken as part of the design process to optimise nitrate removal or post restoration to appraise the functioning of the scheme.
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Pernik, Maribeth. "Mixing processes in a river-floodplain system." Thesis, Georgia Institute of Technology, 1985. http://hdl.handle.net/1853/19514.
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Barker, Kenneth Warren. "Bioavailable Phosphorus in the Bear River System." DigitalCommons@USU, 1988. https://digitalcommons.usu.edu/etd/4400.
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The bioavailable fraction of phosphorus (BAP) in the lower Bear River system waters was investigated. BAP plays a critical role as the limiting nutrient for algal production and eutrophication in proposed reservoirs in the Bear River system. The Bear River system has a hardness rang ing between 180-240 rng/L as CaC03 which significantly affects BAP.
BAP estimation was done by a modified Selenastrum capricornutum Printz Algal Assay Bottle Test. The algal bioassay is considered the best estimator of BAP because no chemical tests or i ndicator parameters are available. Autoclaving and UV radiation were found to be unacceptable means for sterilization because of phosphorus precipitation and inability to kill all the protozoa, respectively. Whole water samples were sterilized by gamma radiation . Hydrogen peroxide formed by gamma radiation was minimized by sparging with nitrogen gas , and adding peroxidase to remove low hydrogen peroxide concentrations. Soluble reactive phosphorus concentrations changed during radiation.
The algal photosynthetic consumption of co2 in the assay procedure raised the pH from 8 to as high as 10, which resulted in significant quantities of phosphorus precipitating with calcium and becoming unavailable. To minimize the effects of precipitation, the following recommendations are made : (1) bubble the bioassay flask with a C02/air gas mixture to minimize pH increase ; and (2) use a high inoculum (105 cells/ml) of S . capricornutum that have been phosphorus starved for several days to maximize luxury uptake.
Bioavailable phosphorus was estimated for each of the sources in Cache County. There are three major point sources (Logan, Hyrum, and Preston wastewater treatment plants) that contribute significant quantities of phosphorus . There are approximately 200 feedlots in the Cache Valley, and approximately 744,000 acres of land in Cache County which contribute runoff to the Bear River system. In Cache County, point sources contribute 2 8 , 20 0 ( 4 6%) kg BAP /yr, livestock runoff contributes 2,500 (4%) kg BAP/yr, and land runoff contributes 28,600 to 33,600 (50%) kg BAP/yr. Bioavailable phosphorus from land runoff was calculated by using export coefficients, which are usually accurate within a factor of two.
A comprehensive phosphorus management plan is required to reduce available phosphorus from all sources to minimize algal blooms in the receiving waters.
4
Moreira, Gina-Lee. "Fluvial system restoration – case study: river Tua." Master's thesis, Faculdade de Ciências e Tecnologia, 2013. http://hdl.handle.net/10362/11096.
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Dissertação para obtenção do Grau de Mestre
em Engenharia do Ambiente, Perfil de Engenharia de Sistemas AmbientaisThe purpose of this thesis is to provide river basin managers with a framework for river restoration. To that end, it presents and discusses the relevant information on the current condition of the river Tua, in northern Portugal, and establishes what can be done to restore the river basin in order to protect the most important drainage basin's functions and ecosystems. It is intended that this thesis will serve as an example of the application of current knowledge on freshwater restoration which can be emulated by future managers in their efforts to restore this, or any water body they wish to. To this purpose, the thesis analyzes demographic data on the municipalities of the Tua drainage basin. It discusses literature and research on the subject of river restoration and important river processes in the following chapter, so as to introduce important theory concepts to have in mind when designing any restoration efforts. In its methodology, the techniques and data assessment tools used in the process of evaluating the river basin's conditions are described and defined, allowing interested managers to review and adapt to the specific needs of drainage basins anywhere. Finally, it presents a practical point-of-view intended to be applied on other freshwater bodies. The thesis includes the realization of an assessment physical characteristics and status of the Tua river reach, it splits up the drainage basin into several different sub-basins, for individual study, and, after a discussion of the conclusions drawn from the assessment for the whole drainage basin, it presents arguments for choosing the sub-sections which present the highest risk to the drainage basin and, as such, require priority action. This section also includes a presentation of the arguments in support of specific techniques to be put into place, given the specific needs of the sub-basin and the restoration goals for the entire drainage basin.
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Shi, Changxing, and 師長興. "Sediment flux through the Yellow River sediment routing system." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2002. http://hub.hku.hk/bib/B29851944.
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Lunn, Rebecca Jane. "A nitrogen modelling system for large river basins." Thesis, University of Newcastle Upon Tyne, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.294852.
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Christmas, Martin. "Phosphorus dynamics in the Swale-Ouse river system." Thesis, Durham University, 1998. http://etheses.dur.ac.uk/4670/.
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A study was made of the phosphorus ecology of the Swale - Ouse river in northern England. It ranges from a stream draining a peat moorland to a mature river influenced by urbanisation (estimated population 250 000) and intensive agriculture. The aims were to assess the concentration and variability of aqueous N and P on spatial and temporal scales, and the response of two common mosses, Fontinalis antipyretica and Rhynchostegium riparioides, to those changes. Key aspects included analysis of water chemistry, internal nutrient contents of mosses, and 'surface' phosphatase activity. The rate of activity of m situ plants was measured over an annual period, in conjunction with short-term studies of transplanted populations. Studies of phosphatase activity in the water also were carried out to assess the biological cycling of phosphorus. Aqueous total phosphorus and total dissolved nitrogen concentration increased on passing down the river. In the upper reaches, total phosphorus comprised equal contributions of dissolved organic and inorganic phosphorus, which were almost certainly derived from diffuse sources. Further downstream, total phosphorus was almost entirely comprised of inorganic phosphorus from point source inputs. The nitrogen and phosphorus content of Fontinalis antipyretica and Rhynchostegium riparioides increased on passing downstream, consistent with the water chemistry. The rate of phosphomonoesterase activity of both mosses was high in the upper reaches of the river, and was inversely related to nutrient content. Fontinalis antipyretica sampled from streams draining peat moorland was shown to have a high phosphodiesterase : phosphomonoesterase ratio. A possible explanation for this is that peat is a potentially rich source of phosphodiester substrate, although increased phosphodiesterase activity may be a response to extreme phosphorus limitation. Transplantation of F. antipyretica showed that internal nutrient content and phosphatase activity respond to changes in ambient nutrients. Aqueous phosphomonoesterase activity was studied over a 12-month period. Laboratory and field studies suggest it plays an important role in the. phosphorus dynamics of the Swale - Ouse river system.
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Allaway, Christopher. "Combined nitrogen retention in an agricultural river system." Thesis, University of Ottawa (Canada), 2006. http://hdl.handle.net/10393/27108.
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Since combined nitrogen is a pollutant in streams, rivers and coastal areas, conditions that favour nitrogen removal were identified. The importance of stream depth as a predictor of a reach's capacity to remove nitrogen was tested in the South Nation watershed (3915 km2), an agricultural watershed in eastern Ontario. Combined nitrogen (N) retention was estimated in 48 reaches across the watershed which varied in discharge (0.0008--118 m3 s-1), length (350 m to 5.2 km) and size from headwaters to the outflow of the South Nation River at the Ottawa River. Retention dynamics were also investigated within a few sites over the summer season.
Retention efficiency (expressed as a percentage of inputs) varied widely for nitrate from almost complete removal within a reach to reaches acting as a net source. A narrower range in percent retention and loading was observed for total nitrogen (TN) among the sites suggesting that some forms of combined nitrogen are relatively inert. (Abstract shortened by UMI.)
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Fleckenstein, Jan Henrich. "Modeling river-aquifer interactions and geologic heterogeneity in an alluvial fan system, Cosumnes River, CA /." For electronic version search Digital dissertations database. Restricted to UC campuses. Access is free to UC campus dissertations, 2004. http://uclibs.org/PID/11984.
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Tijani, Fatai Oladapo. "Scale effect in nutrient transport along a rural river system : the river Eden, Cumbria UK." Thesis, University of Newcastle upon Tyne, 2016. http://hdl.handle.net/10443/3683.
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Many research studies on nutrient transfer are conducted at small scale and transferring such findings to the large scale at which planners and catchment managers work faces uncertainties because of non-linearity. There is a need therefore for multiscale studies, which define and link the transfer mechanisms across spatial scales. Such a study may also provide the answers on the processes driving it and test the answers further by using a model. Experimental data to support the study were collected from two complementary research programmes in the Eden catchment. Spatial scale variations were investigated through seasonal and spot samples down a sequence of nested catchments, area 1 – 1400 km2, from the NERC-funded Catchment Hydrology and Sustainable Management project (CHASM). Soil samples were also taken. These samples were analysed in the laboratories for nitrate, phosphates and suspended sediment using standard methods. The explanation of spatial variation was then supported by data from two contrasting 10 km2 catchments of the DEFRA-funded Demonstration Test Catchments (DTC) project. A generalisation of the findings was carried out by deploying the TOPCAT-NP model. The nitrate, phosphorus and the suspended sediment concentration, load and yield increased downstream relative to the headwaters. Nitrate sources were complex and appear dominated by groundwater source whereas phosphorus and suspended sediment were from diffuse sources. Nitrate showed the clearest increasing pattern downstream when compared with the other nutrients. A downstream increase in nutrient transfer relates to a downstream increase in flow, agricultural land use and soil type. Hydrology of Morland was adequately represented by the model but the nutrients were less accurate leading to suggestions on model improvement. By carrying out a spatial scale related study of the Eden catchment, analysing the DTC high resolution data and modelling the data, insights into how, where and when nutrients losses occur have been gained. This encourages us, in that targeted land management and a better understanding of the hydrological processes that drive nutrient losses may be an effective way to reduce the problem.
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Mills, Carolyn. "Spatial variability and scale dependency yield in a rural river system- The river Eden, Cumbria, UK." Thesis, University of Newcastle Upon Tyne, 2009. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.512025.
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Wilkinson, Chad Eric. "Sportfish population dynamics in an intensively managed river system." Thesis, University of British Columbia, 2009. http://hdl.handle.net/2429/10179.
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The Elk River valley is intensively utilized by various resource industries including a recreational fishery that predominates in the river section between Sparwood and Elko. Most angling comes from fly-fishers in drift boats who mainly target westslope cutthroat trout (WCT) Onchorhyncus clarkii lewisi in the summer, but also secondarily catch bull trout (BT) Salvelinus confluentus. Non-native rainbow trout (RB) Onchorhyncus mykiss and Eastern brook trout (EB) Salvelinus fontinalis have also been introduced to the system. The river’s trout and char populations have never been directly examined in response to fishing regulations. In 2006 and 2007, I used ecological survey methods to determine WCT growth, mortality, and abundance in a series of catch-and-release and catch-and-keep regulation zones of the lower mainstem Elk River. I assessed the angling effort response to WCT and BT densities in the lower mainstem and systematically determined the relative recruitment capability of the two drainage basins in the tributary system.
I estimated 10,050 WCT inhabited the lower mainstem in 2006 with 16,200 WCT in 2007, indicating an annual recruitment of 5,753 fish into the mainstem. Growth was inversely related to fish density, particularly in the first fractal plane of the tributary system. Effects on mortality due to fishing pressure could not be directly determined from effort, but mortality rates were slightly higher in the harvest zones in 2007, especially in the first fractal division of tributaries. Angling effort showed a linear increase with WCT densities. In the tributary system, the highest WCT densities were found in the Michel drainage, whereas BT recruitment appeared largely restricted to the Upper Elk drainage. A strong EB presence in the upper Michel drainage coupled by an absence of BT suggests that EB have displaced BT in warmer streams in this river system, which may even lead to improved WCT densities. This initial investigation indicates that active monitoring of the Elk River sportfish populations can feasibly be integrated into a system-wide adaptive management strategy.
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Melvill, James Alexander. "Real-time model development for the full river system /." Link to the online version, 2007. http://hdl.handle.net/10019/1999.
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Hayden, Jesse Thomas. "Indian River Inlet Bridge and Bathymetry Scour Monitoring System." Access to citation, abstract and download form provided by ProQuest Information and Learning Company; downloadable PDF file, 163 p, 2009. http://proquest.umi.com/pqdweb?did=1885754611&sid=2&Fmt=2&clientId=8331&RQT=309&VName=PQD.
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Graham, Stephen Thomas. "Continental river routing for fully coupled climate system models /." Full text (PDF) from UMI/Dissertation Abstracts International, 2000. http://wwwlib.umi.com/cr/utexas/fullcit?p3024456.
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Hattingh, Keaton Jade. "Geomorphological controls on pool formation and pool persistence in non-perennial river systems." University of the Western Cape, 2020. http://hdl.handle.net/11394/7739.
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>Magister Scientiae - MScGlobally climate variability and anthropogenic effects are causing more perennial rivers to become non-perennial rivers. Non-perennial rivers are distinguished by their isolated pools which serve as refugia for aquatic organisms, water birds, and riparian vegetation. The literature on non-perennial rivers demonstrates that pools are poorly understood in terms of their location, nature, and geomorphic persistence. Therefore, this study examines the relationships between the spatial distribution, morphology, and substrate characteristics of pools in reaches of the Prins and Touws rivers in the Klein Karoo. A greater understanding of pools will facilitate better management, monitoring, and restoration strategies for pool ecology since the geomorphology of pools provides a key part of the ecological template. Worldview-2 satellite imagery (2017) and orthorectified aerial photography (2014, 2013, and 1944) were used to assess the effects of major flooding events on pools over time. A DGPS (Differential Global Positioning System) was used to survey the pool widths, lengths, depths, and valley widths, cross-sections, and longitudinal profiles of the river. Sediment samples and Wolman pebble counts were used to assess the grain size and organic matter content of each pool in the study area. Detailed descriptions of the characteristics of each pool in terms of position in the channel, valley form, and obstruction presence and type were also assessed. Results indicate that most of the large pools occur at bedrock outcrops of the valley margins, and smaller pools are associated with Vachellia karroo debris bar features. Larger and highly persistent pools are associated with valley confinement and smaller less persistent, scour pools occur mid-channel where the valley expands. Analysis of the results shows that the valley width is the dominant control on these forced pools. The type of obstruction also plays a role in the formation of the pool as large woody debris results in smaller pools whereas, bedrock outcrops result in larger sized pools. A significant relationship was found between the grain size and organic matter content of pools. Aerial photography of the spatial distribution of the pools revealed that before a major flood, the pools were small and patchy, whereas afterward, they were larger and more elongated. It is suggested that at the bedrock outcrops, major scouring and eddy processes drive the formation of larger pools during large flood events, whereas pool dissection by sediment deposits prevails during intervening intermediate to low flow periods. The results are discussed in terms of the geomorphic controls (valley width, pool dimensions, morphology, substrate, and obstruction characteristics) on the formation and maintenance of pools in dryland settings. A conceptual model is proposed to explain the geomorphic changes of the pools in the four geomorphological zones of non-perennial rivers.
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Visser, Alwyn Jacobus Christiaan. "Real-time management of river systems by using a hydrodynamic model with optimisation." Thesis, Stellenbosch : University of Stellenbosch, 2010. http://hdl.handle.net/10019.1/5438.
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Thesis (MScEng (Civil Engineering))--University of Stellenbosch, 2010.ENGLISH ABSTRACT: In this research a Real-Time hydrodynamic optimisation model of the Orange-Fish-Sundays River (OFS) system which uses real-time data in order to forecast release hydrographs, is evaluated. The OFS system stretches over three catchment areas in the Eastern Cape namely Great Fish, Little Fish and Sundays Rivers. The OFS supplies water from the Orange River through a 800 km system of canals, tunnels, dams and rivers to registered water users in this area. In order to cope with increasing pressures on water saving, water demand, water quality and dam safety, the Department of Water Affairs implemented this Orange Fish Sundays-Real Time (OFS-RT) system to calculate the optimal water flow, by running customised Danish Hydraulic Institute (DHI) MIKE11 software. The system utilizes an optimisation module that evaluates the simulated outcome at seven water release structures (dams, weirs and tunnels). Then during the optimisation process performs more adjustments to reach the objectives of the system to obtain the forecast release hydrographs. This OFS-RT model aims at target based objectives, using: (i) Hydras real-time field data of dam water levels, river flows and water quality from the area sent to the control office main computer at four hourly intervals via SMS and (ii) abstractors weekly water requests. This system takes irrigation and domestic demand into account as well as water quality, evaporation, rainfall, dam levels, dam safety, instream flow requirements and tributary flow. In order to manage the water flows through the OFS system the OFS-RT model forecasts the release hydrographs and uploads the predictions to a website to smooth operational procedures. The target outcomes were tested and evaluated during this research and it was found that the OFS- RT model succeeded in delivering release forecasts for the seven control structures to manage the OFS system. This research proved that management of river systems by using a real-time hydrodynamic model with optimisation is a useful tool for the optimal utilisation of water resources.
AFRIKAANSE OPSOMMING: Die doel van hierdie navoring is die evaluering van „n intydse hidrodinamiese optimiseringsmodel van die Oranje-Vis-Sondagsrivier (OVS) stelsel wat intydse data ontvang en loslatings hidrograwe verskaf. Die OVS stelsel strek oor drie opvangsgebiede in die Oos-Kaap: naamlik die Groot Vis-, Klein Vis- en Sondagsriviere en voorsien water vanuit die Oranjerivier deur „n 800 km stelsel van kanale, tonnels, damme en riviere, aan geregistreerde waterverbruikers in die gebied. Ten einde te voldoen aan die eise van waterbesparings, stygende vraag na water, die verskaffing van goeie water gehalte en damveiligheid, het die Departement van Waterwese „n intydse rekenaar model (OVS-IT) geïmplimenteer om die optimale watervloei deur middel van die aangepaste MIKE11 sagteware van die Danish Hydraulic Institute (DHI) te bereken. Hierdie stelsel maak gebruik van „n optimisering module wat die gesimuleerde uitkomste van verstellings aan sewe waterloslatingstrukture evalueer. Met optimisering word die verlangde hidrograaf deur verder aanpassings verkry. Data wat nodig is om die OVS-IT model se doel te bereik is: (i) Hydras intydse velddata van damwatervlakke, riviervloeie en water gehalte van die gebied ontvang deur die beheerkantoor se hoofrekenaar via SMS elke vier ure, en (ii) water verbruikers se weeklikse wateraanvrae Die stelsel neem die besproeiing en huishoudelike aanvraag in ag, sowel as soutgehalte, verdamping, reënval, damvlakke, dam veiligheid, stroom vloei vereistes en sytak byvloei. Die OVS se watervloei word beheer deur voorspelde loslatings hidrograwe, opgesom op „n webwerf wat die uitvoer prosedures aandui. Die intydse hidrodinamiese model met optimisering het volgens hierdie navorsing daarin geslaag om vir die beheer van die OVS stelsel, die loslatings van sewe beheerstrukture akkuraat te voorspel en bevind dat die model „n waardevolle instrument is vir die optimale bestuur van waterhulpbronne.
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Ainsworth, Andrew Mark. "Microbial organic nitrogen transformations in the River Swale-Ouse system." Thesis, University of Hull, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.301371.
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Broad, K. J. "Population dynamics of juvenile salmon of the Wye river system." Thesis, Cardiff University, 1987. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.378462.
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Momoh, Jinnah Samuel. "Decision support system for river water quality forecasting and management." Thesis, University of Newcastle Upon Tyne, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.246651.
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Pillsbury, Lori A. "Spatial and temporal chemical variations in the Hillsborough River system." [Tampa, Fla.] : University of South Florida, 2004. http://purl.fcla.edu/fcla/etd/SFE0000223.
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Rice, Stephanie Kimberly. "Suspended sediment transport in the Ganges-Brahmaputra River System, Bangladesh." [College Station, Tex. : Texas A&M University, 2007. http://hdl.handle.net/1969.1/ETD-TAMU-1588.
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Moran, Kate Anne. "Aging Juvenile Gulf Sturgeon From the Apalachicola River System, Florida." Miami University / OhioLINK, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=miami1527187111928485.
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Fischer, Jason L. "Evaluating Habitat Restoration in the St. Clair-Detroit River System." University of Toledo / OhioLINK, 2019. http://rave.ohiolink.edu/etdc/view?acc_num=toledo1576160707431634.
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Allen, Lorraine Gillian. "The evolution of the Solent River system during the Pleistocene." Thesis, University of Cambridge, 1991. https://www.repository.cam.ac.uk/handle/1810/251498.
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Tashev, Azamat. "Understanding Ecosystem Services through Organizational Analysis: Application to the Truckee-Carson River System." Ohio University / OhioLINK, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1515072255449453.
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Simsek, Gul. "An Approach To Urban River Rehabilitation For Coexistence Of River And Its Respective City: Porsuk River Case And City Of Eskisehir." Phd thesis, METU, 2011. http://etd.lib.metu.edu.tr/upload/12613339/index.pdf.
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All living things mostly the humans, as builders of civilizations, have always been in intrinsic bonds with water. This interaction between water (oceans, seas, lakes, rivers etc.) and settlements has existed since ancient civilizations. Among water resources, &lsquoflowing waters&rsquo
such as rivers, streams, creeks, etc. have a prominent role as they are the lifeblood of most cities in terms of providing transportation, security, energy, irrigation, commerce, and recreation. By the late 19th century, developments of terrestrial transportation modes diminished the magnetism of rivers and riverfronts, and growing industries led to the deterioration of rivers. Owing to these reasons, along with many others, they turned into sewage channels, were covered up, and became water scopes detached from the urban life. Particularly since the 1970s, with more attention given to sustainability of resources, a greater awareness has grown of the vital role of urban rivers as a resource for humans and a lifeline for cities. After being neglected for decades, urban rivers have started to be rehabilitated to solve the related problems. The new approach to urban river rehabilitation beyond classical practices that aim at recovering the physical conditions of rivers has come to the fore to address the problems comprehensively. Instead of independent and one-dimensional practices, the urban rivers have become to be seen as a vital part of urban water system and of the city itself. While rehabilitating urban rivers, recovering river health can be ensured provided that the entire urban water ecosystem is taken into consideration. The ecocity approach is one of the major new approaches that geared toward achieving a healthy city, and sustainability of water system is the significant goal within this approach. In this regard, the thesis first asserts that the ecocity criteria are likely to give way to a more sustainable future for urban rivers. Besides being a part of the ecosystem, urban rivers have transformed together with the surrounding built environment throughout the history of cities. Significant focal elements of the urban pattern, urban rivers should be dealt with other urban focal points, with the introduced concept of river-city integration, which is proposed as the second assertion of the thesis. In this respect, the study attempts to investigate urban rivers and their rehabilitation in relation with both the ecocity approach, and the river-city integration concept. The research methodology in the present study involves comparative anaysis of best practices and case study analysis. Porsuk River and the city of Eskisehir, which the river passes through, were selected as a case for empirical study. Criteria sets that determined within the frames of ecocity and river-city integration, and the testing of the criteria in the case area offers an opportunity to contribute to literature of river and city coexistence.
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Germain, Richard James. "Drought management using a geographical information system." Ohio : Ohio University, 1996. http://www.ohiolink.edu/etd/view.cgi?ohiou1178651687.
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Langevin, Robert. "Genotoxicity in water and sediment extracts from the St. Lawrence river system, using the SOS chromotest." Thesis, McGill University, 1991. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=60498.
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Surface water and sediments from the St. Lawrence River system (Quebec region) were analysed for genotoxicity using nonlinear SOS Chromotest parameters, as well as for their chemical concentrations of polycyclic aromatic hydrocarbons and heavy metals. Additionally, sediments chlorobenzenes, polychlorinated biphenyls, organochlorinated pesticides, ammonia and nitrites concentrations were determined. Organic contaminants were extracted dichloromethane. For surface water, fifteen extracts of filtered water and seven of particulates, and for sediments, one extract of pore water and three of particulates proved to be weakly genotoxic. All but one of the genotoxic responses observed in the surface water were obtained from samples taken from the highly industrial portion of the St. Lawrence River system, with the strongest responses observed in Lake St-Louis. Surface water genotoxicants partitioning favors the particulate fraction. Bottom particulates genotoxicity was one thousand fold weaker than suspended particulates. Additionally, whole sediments were extracted with a 10% dimethylsulfoxide-saline solution. Genotoxicity of hydrophilic contaminants was detected in all extracts. The observed distributions of genotoxicity values did not correlate with observed concentrations of demonstrated SOS inducers, mutagens and/or carcinogens, nor with the presence of other toxic chemicals.
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Becker, May Ling Luettich Richard A. "Hydrodynamic behavior of the Cape Fear River estuarine system, North Carolina." Chapel Hill, N.C. : University of North Carolina at Chapel Hill, 2006. http://dc.lib.unc.edu/u?/etd,2965.
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Thesis (Ph. D.)--University of North Carolina at Chapel Hill, 2007.Title from electronic title page (viewed Jun. 23, 2010). "... in partial fulfillment of the requirements for the degree of Doctor of Philosophy in the Department of Marine Sciences Physical Oceanography." Discipline: Marine Sciences; Department/School: Marine Sciences.
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Noyes, Thomas Kelly. "Nutrient levels and biostimulation in the lower Colorado River/reservoir system." Thesis, The University of Arizona, 1985. http://etd.library.arizona.edu/etd/GetFileServlet?file=file:///data1/pdf/etd/azu_e9791_1985_104_sip1_w.pdf&type=application/pdf.
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Williams, Mark Donald. "Salinity tolerance of small fishes from the Murray-Darling river system /." Title page, contents and conclusions only, 1987. http://web4.library.adelaide.edu.au/theses/09SB/09sbw725.pdf.
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Zhu, Xuanlin. "A Feasibility Study of Using River Water in University Cooling System." Thesis, Högskolan i Gävle, Avdelningen för bygg- energi- och miljöteknik, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:hig:diva-19660.
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This thesis is to study the feasibility of using river water from Gavleån in the cooling system of University of Gävle. The project is proposed by the campus service manager Akademiska Hus AB which intended to replace the current cooling production system with the water cooling system to reduce the electricity cost in cooling production. The river by direct distance is 600 meters from the university, the river water is to be extracted from the river via a pump house, flow through pipeline buried underground and delivered to the equipment house of Akademiska Hus. Most water source cooling prefer water body with decent depth which contain low temperature water to use as free cooling source, but the issue that limits the practice is, the decent depth is not a very common feature of most water body near or within urban area. Like Gavleån which has an average depth of not over five meters while the sufficient depth is over 50 meters for the least or 70 meters to 100 meters often. So study the potential of using rather high temperature water from shallow water body can be of high interest for most cooling consumers. The thesis progressed through the work in five parts. To introduce cooling in general starting with literature review, the concept, the mechanism, the device for end use and production, the demand of cooling and the reason behind it. Followed by case studies of water source cooling projects worldwide, which is mostly deep water source cooling, and another case of the local hospital cooling system that extract water from Gavleån, demonstrate the use of shallow water body in assisting cooling production, it gives some insights how the potential if similar system is to be implemented in the campus, which is mounted on the same river. Several tours to the hospital were taken to acquire data and understanding of the system. Then the water temperature measurement from Gavleån in 2014 summer is presented. The measurement was carried out at a small dock by the river side during July to September of 2014. The measurements show the temperature of river water has been increasing which limits free cooling throughout the year, additional refrigerator is required to produce chilled water. The river water, in the hot seasons is used as cooler for the refrigerator and in cold season can be used for free cooling directly. Simulation of IDA-ICE gives the cooling demand of modelled building blocks, the output of cooling production season (consistent with the hot seasons) matches the cooling consumption data from Akademiska Hus by an error of 1% (414743 kWh of simulated result to 415270 kWh in documentation of Akademiska Hus). To meet the demand of cooling and select more cost-effective refrigerator type, consumption and COP (COP: Coefficient of Performance) are calculated for compressor chiller and absorption chiller with basic cooling cycle for both. The results shown compressor chiller has much better performance but also higher consumption in electricity, while absorption chiller has rather low COP value in comparison but the need of energy input is much less given by its major consumption of energy is heat from hot water, already a purchased item by the university from district heating network. Cost-effectiveness wise speaking absorption chiller is a more optional choice. Reasonable values of assumption are largely employed in the calculation to select the better candidate and bring certain errors, which is then exam in sensitivity analysis to weigh the alternative parameter and the outcome from it. The last part is to estimate the cost of chillers and pipeline, for the concern of minimizing errors due to uncertainty the operation cost, labor cost and future energy price are not included. As the calculation turns out the payback year of the new system can range from 7 to 12 years by different refrigerator setup and pipeline routine design, which is considered within the life time of the chiller and pipeline, also lower than the current cooling cost of the university and therefore concluded as promising investment. Discussion and conclusion exam and finalize the whole thesis work. For the uncertainties of the calculation, the lack of information and data, which are improvements, can be done in future work. Also the improvements in other perspectives noted in terms of better load management for the cooling production units so the cost of equipment can be reduced, changes in building attachment and cooling device to reduce the demand of cooling, etc. But mostly draw the conclusion that with proper system configuration shallow water body can be helpful in reducing cooling consumption, and be a promising option for cities that have access to such water body.
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Bembo, David Geraint. "The brown trout (Salmo trutta L.) of the River Usk system." Thesis, Cardiff University, 1992. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.364473.
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Sass, Christopher Kevin. "Inventory and analysis of the Black Vermillion river system riparian corridors." Thesis, Manhattan, Kan. : Kansas State University, 2008. http://hdl.handle.net/2097/1006.
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Burns, Emily. "Assessing exposure and risks of pharmaceuticals in an urban river system." Thesis, University of York, 2018. http://etheses.whiterose.ac.uk/20448/.
Full textAbstract:
Pharmaceuticals are ubiquitous in the freshwater environment, a result of an increasingly urbanised water cycle. Environmental risk assessments are available for a small proportion of the over 1900 pharmaceuticals in use, raising concern over the potential risks posed by pharmaceuticals with limited data, as effects on non-target organisms have been observed. Experimentally filling these gaps is a large, costly and likely unnecessary task. Risk-based prioritisation is a potential tool for addressing this challenge by identifying which pharmaceuticals may pose risks and are therefore a priority for study. Simple exposure models are commonly used to predict environmental concentrations (PECs), however the suitability of these models for prioritisation is unknown. A scoping study targeted 95 pharmaceuticals in samples from the Rivers Ouse and Foss in York, UK, 25 were quantified. Measured environmental concentrations (MECs) were compared with simple PECs based on local usage data and dilution factors. MECs and simple PECs were used to prioritise pharmaceuticals and, for the larger River Ouse, different priority lists using the two approaches emerged. This conclusion was based on limited monitoring data, therefore an HPLC-MS/MS quantification method for 33 pharmaceuticals was developed, validated and applied to a year-long monitoring campaign to build a robust monitoring dataset. Significant spatial and temporal trends were observed in both rivers apparently driven by flow, pharmaceutical usage, wastewater treatment removal, and in-stream attenuation. These drivers differently influenced concentrations in either river. The simple PECs and PECs derived from a higher-tier spatial exposure model (LF2000-WQX) were validated against annual average MECs. LF2000-WQX outperformed the simple PEC in both rivers. A re-prioritisation using LF2000-WQX demonstrated that improved predictive power translated into better agreement of prioritisation outcomes with MECs. The use of simple PECs for the prioritisation and risk assessment of pharmaceuticals should be avoided and the use of higher-tier spatial exposure models encouraged.
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Solo-Gabriele, Helena. "Metal transport in the Aberjona river system : monitoring, modeling, and mechanisms." Thesis, Massachusetts Institute of Technology, 1995. http://hdl.handle.net/1721.1/11723.
Full textAbstract:
Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Civil and Environmental Engineering, 1995.Includes bibliographical references (v. 1, p. 421-431).
by Helena Solo-Gabriele.
Ph.D.
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Jones, Roy William. "Aquatic invasions of the Nseleni River system: causes, consequences and control." Thesis, Rhodes University, 2015. http://hdl.handle.net/10962/d1017806.
Full textAbstract:
Globalization has seen an unprecedented dispersal of exotic and alien species worldwide resulting in worldwide homogenization and sometimes extinction of indigenous or endemic taxa. When an exotic species becomes established in a new habitat the invasive organisms are capable of having an impact on indigenous community dynamics and the overall structure and function of ecosystems. Furthermore, the impact of invasion is determined by the geographical range, abundance and the per-capita or per-biomass effect of the invader. However, the success of the introduced organisms is reliant on their ability to acclimate to the physiochemical conditions of the newly invaded environment.Freshwater ecosystems are especially vulnerable to invasions because there are numerous potential routes of introduction including intentional pathways such as stocking, and unintentional pathways such as the release of ballast water and aquarium releases. Efforts to limit the introduction of invasive species or to manage established exotic populations are often hindered by insufficient understanding of the natural history of problematic species. Relatively little is known regarding the physiological tolerances of many taxa. Knowledge about specific species ecophysiological constraints allows for the prediction of future patterns of invasion more accurately, including where an introduced organism would probably survive, thrive and disperse. Furthermore, data on the physiological tolerances of an introduced exotic organism may provide data necessary for effective management and control. This studyinvestigated three invasive species in the Nseleni River system in a protected area in KwaZulu-Natal. The species studied were, Tarebia granifera (Quilted melania – Lamarck, 1822), Pterygoplichthys disjunctivus (Suckermouth armoured catfish - Weber, 1991) and Eichhornia crassipes (water hyacinth – (Martius) Solms-Laubach,). The Nseleni River flows into Lake Nsezi which is responsible for providing potable water to the surrounding towns and industry, as well as the surrounding rural communities. The Enseleni Nature reserve has become the centre for biodiversity dispersal in the immediate area, due to the change in landscape surrounding the protected area.An important step in developing alien invasive species management strategies in protected areas is determining their extent and invasive traits. Tarebia granifera is a prosobranch gastropod originally from South-East Asia that has become invasive in several countries around the world including South Africa. Snail populations were sampled at nine sites throughout the Nseleni/Mposa river system every six weeks over a twelve month period. The snail was abundant throughout the system, especially in shallow waters of less than 1m in depth.The first positive identification the loricariid catfish Pterygoplichthys disjunctivus for the Nseleni River was in 2006. The original introduction is believed to have been via the aquarium trade. The aim of the study was to assess the usefulness of the unified framework with regard to management of fish invasions by assessing the invasion stage of the loricariid population and identifying appropriate management actions using the Blackburn et al. (2011) framework. The fish were sampled at nine different sites and three different depths over a period of twelve months, as well as when two ichthyological surveys were carried out on the Nseleni River system. This invasive fish has been located throughout the system and both male and female fish were collected. The smallest fish sampled was a fingerling of a day or two old and the smallest pregnant female was a mere 270mm TL. This is a clear indication that this fish is breeding in the river system.Although T. granifera and P. disjunctivus were abundant in the Nseleni/Mposa river system, it was not clear what their role in the system was, and in particular if they were competing with any of the indigenous species. Therefore, isotope samples were collected from numerous taxa over a two week period, with the exception of Pterygoplichthys disjunctivus samples, which were collected over 12 months. The δ13C and δ15N signatures of all samples were determined. The niche overlap between the invasive and indigenous snails was effectively zero (1.02E-13%), indicating no shared food resources. The medium ranges of dNRb (7.14) and dCRb (9.07) for the invasive fish indicate that it utilizes a wider range of food resources and trophic levels than the majority of indigenous fish. A medium CDb value (2.34) for the invasive fish species, P. disjunctivus, describes medium trophic diversity, with three indigenous species possessing higher diversity and three possessing lower diversity. Furtherresults indicated that there was no direct dietary competition between P. disjunctivus and indigenous species. Eichhornia crassipes was first recorded on the Nseleni River in 1978, and has been shown to have a significant negative impact on the biodiversity of the Nseleni/Mposa River system and therefore required a control intervention. Although biological control using the two weevil species Neochetina eichhornia (Warner) and N. bruchi (Hustache) has been credited with affecting a good level of control, the lack of a manipulated post-release evaluation experiments has undermined this statement. Five experimental plots of water hyacinth of 20m2 were sprayed with an insecticide to control weevils. After ten months the plants in the sprayed plots were significantly bigger and heavier than those in the control plots that had natural populations of the biological control agents. This study has shown unequivocally that biological control has contributed significantly to the control of water hyacinth on the Nseleni/Mposa River system.The management plan for the Enseleni Nature Reserve identifies the need to control invasive and/or exotic organisms within the boundary of the protected area. In addition, set guidelines have been implemented on how to control these organisms, so that indigenous organisms are least affected. Lack of control of exotic organisms can have serious consequences for indigenous species. It is therefore of utmost importance that the population dynamics of the invading organism be understood, what the potential impact could be and how to control them. Furthermore, it has also acknowledged the threat of possible exotic species invasions from outside of the protected area that might result in threats to the protected area and that these must be investigated, researched and managed.This thesis has identified Tarebia granifera, Pterygoplichthys disjunctivus and Eichhornia crassipes as being a threat to indigenous biodiversity within the protected area, as well as in adjacent areas to the protected area. The thesis will therefore investigate the hypothesis that both Tarebia granifera and Pterygoplichthys disjunctivus are having a direct negative effect on available food resources for indigenous species of organisms. In addition, this thesis will investigate if theNeochetina species that have previously been introduced onto E. crassipes are having any negative effect on this invasive alien aquatic plant.
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Parkin, Geoffrey. "A three-dimensional variably-saturated subsurface modelling system for river basins." Thesis, University of Newcastle upon Tyne, 1996. http://hdl.handle.net/10443/3161.
Full textAbstract:
There are many circumstances where lateral flows in the upper soil layers above the regional groundwater table are important for hillslope and catchment hydrology, and in particular for the transport of contaminants. Perched water tables frequently occur in Quaternary drift sequences, reducing rates of recharge to the underlying aquifers and altering contaminant migration pathways; recent experimental and modelling studies have demonstrated the potential importance of lateral flows in the unsaturated zone, even in homogeneous soils; and lateral interflow at the hillslope scale, and its role in generating storm runoff, is the subject of intense current debate amongst hydrologists. A numerical model for simulating transient three-dimensional variably-saturated flow in complex aquifer systems (the Variably-Saturated Subsurface flow, or VSS, model), capable of representing these conditions, is presented in this thesis. The VSS model is based on the extended Richards equation for saturated as well as unsaturated conditions, and also includes capabilities for modelling surface-subsurface interactions, stream-aquifer interactions, prescribed head and flow boundary conditions, plant and well abstractions, and spring discharges. A simple but novel approach is taken to solving the three-dimensional non-linear Richards equation on a flexible-geometry finite-difference mesh, using Newton-Raphson iteration and an adaptive convergence algorithm. The VSS model is implemented as a module of the catchment flow and transport modelling system, SHETRAN. The reliability of the full SHETRAN modelling system is demonstrated using verification and validation tests, including comparisons against analytical solutions for simple cases, and simulations of storm runoff in a small Mediterranean catchment. Simulations of flow and contaminant transport in complex sequences of Quaternary drift deposits demonstrate the full capabilities of the modelling system under real-world conditions.
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McGregor, Heather Elizabeth. "Decolonizing the Nunavut school system : stories in a river of time." Thesis, University of British Columbia, 2015. http://hdl.handle.net/2429/52592.
Full textAbstract:
This research explores the recent history of educational change in Nunavut’s public school system, primarily between the years 2000 and 2013. During this time, decision makers mandated that schools deliver programs in accordance with Inuit foundations of knowledge, values and ways of being. I show how new school system initiatives were largely informed by long-term Nunavut educators—Inuit and non-Inuit—as well as Elders and Inuit knowledge holders, whose perspectives reach into the remembered past and towards an imagined future. My inquiry centres in-depth interviews with Cathy McGregor, an educational leader who carries 40 years experience North of 60°, and was responsible for facilitating many recent curriculum, policy, and leadership changes. Cathy is also my mother. Illuminated by her memories and vision, materials developed for the Nunavut school system, and my own research journey, I examine processes of bringing knowledge from and about the past forward in educational change. I describe three sites as demonstrating decolonizing: 1) The role of Inuit Elders in the school system, including full-time Elder Advisors; 2) Processes of curriculum development based on Inuit Qaujimajatuqangit; and, 3) An annual leadership development workshop facilitating history education. Building on these stories of change, I work towards theorizing two concepts, and the relationship between them, in the context of the Nunavut school system: decolonizing and knowing with historical consciousness. I find the sustainability of change in this context is elusive and challenging. Educators are unlikely to reach a stable moment of fulfillment wherein they hold sufficient knowledge of the context, or where the institution of schooling is decolonized. Using the metaphor of a river melting in spring throughout the dissertation, I find it is unsettling to acknowledge that time constantly slips away; that what was done before may no longer be relevant or possible now. However, knowledge from and about the past may serve educators by illustrating that knowing is always conditioned by place, time, identity, and relationships; therefore, knowledge can, and must, be remade. I argue that this warrants practices of continuously and recursively revisiting what is called for in Nunavut schools, to support educational change towards decolonizing.Education, Faculty of
Curriculum and Pedagogy (EDCP), Department of
Graduate
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Tomscha, Stephanie Anne. "Long-term mapping of ecosystem services in a river-floodplain system." Thesis, University of British Columbia, 2015. http://hdl.handle.net/2429/55624.
Full textAbstract:
Humans derive a wide range of benefits from ecosystems, known as ecosystem services (ES). At the nexus of land and water, floodplains are particularly important for providing ES. Recently, problematic declines in ES have motivated research to better understand their spatial distributions. However, the temporal dynamics of critically important floodplain-specific ES remain poorly understood. These spatial and temporal dynamics as well as trade-offs that occur when management enhances one ES at the expense of others are particularly germane as a warming climate alters river flows. Landscape history is foundational to elucidating these dynamics. Here, I explore the importance of landscape history for understanding the historical, contemporary, and future distributions of ES in the Wenatchee watershed, central Washington State. Using several widely-used datasets in novel ways, my dissertation has five primary objectives (1) quantify the relative importance of different landscape positions for frontier settlers, (2) map change in ES from 1949-2006 using high-resolution imagery, (3) enhance understanding of ES interactions by incorporating change in ES over time, (4) explore the spatial distribution of floodplain-specific ES, and (5) conceptualize shifts in ES under future climates. I found riparian zones and floodplains were disproportionately important for frontier settlement, setting the stage to explore floodplain-specific ES in more detail. ES were dynamic from 1949-2006, largely driven by increasing urbanization and forest densification. Next, I showed how history can provide important insights into ES interactions. Finally, I also found floodplain ES varied considerably with floodplain position. Analyses over broad time frames and at fine spatial scales greatly enhance our understanding of ES dynamics, highlighting the need for long-term monitoring for ES, especially as ES continue to interact under future climates.Forestry, Faculty of
Graduate
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Sinnadurai, Paul. "The ecology of Riparian Carabidae (Coleoptera) in a regulated river system." Thesis, Cardiff University, 2014. http://orca.cf.ac.uk/68179/.
Full textAbstract:
Rivers and riparian zones are among the most threatened ecosystems globally, with modification of their natural flow regime a major source of change. Exposed riverine sediments (ERS) are characteristic of unregulated rivers in their upper and middle reaches and among the few remaining natural riparian habitats. However, they are in decline across the UK and Europe as a result of widespread modifications to channel structure and flow regimes. Studies of ERS and their dependent carabid beetles can help to understand how environmental change is affecting river ecosystems more generally, but prolonged research is scarce. This thesis reports on a three year study of carabid beetles at multiple sites in the Usk river system, Wales, during an extended period of low river discharge. Plot-scale experimentation and reach-scale surveys showed consistently that carabid assemblage structure and distribution varied more strongly in response to time and across the reach than to within-patch habitat character. There was no evidence of carabid assemblage succession, though generalist species richness appeared to increase through the study as specialist species richness declined, and general conditions for specialist species may have declined. It is suggested that specialist carabids of high conservation importance could be squeezed as land use encroachment and river regulation causes a decline in the ERS resource. Management interventions at the reach- or catchment scale are advocated to maintain and restore the ephemerality of ERS. Being responsive to reach- and catchment scale events, exposed riverine sediments and their dependent fauna should be the focus of long term study to appraise rates of environmental change or resilience to anthropogenic stressors. In particular, long term studies may not only reveal trends on ERS towards homogenisation, indicative of environmental decline within the wider river system, but might also help to detect the effectiveness of river restoration.
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Wang, Ya, and 王亚. "Isotopic and hydrogeochemical studies of the coast aquifer-aquitard system in the Pearl River Delta, China." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2011. http://hub.hku.hk/bib/B46593597.
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Chambers, Jennifer Catherine. "The spatial modelling of palaeolithic secondary context assemblages : case studies from the Solent river system and Axe river valley, UK." Thesis, University of Southampton, 2004. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.414649.
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Sorooshian, Soroosh, Hoshin Gupta, Terri S. Hogue, Andrea Holz, and Dean Braatz. "A multi-step automatic calibration scheme (MACS) for river forecasting models utilizing the national weather service river forecast system (NWSRFS)." Department of Hydrology and Water Resources, University of Arizona (Tucson, AZ), 1999. http://hdl.handle.net/10150/615749.
Full textAbstract:
Final Report to the Hydrologic Research Laboratory of the National Weather Service Grant NA #87WHO582Traditional model calibration by National Weather Service (NWS) River Forecast Center (RFC) hydrologists involves a laborious and time -consuming manual estimation of numerous parameters. The National Weather Service River Forecasting System (NWSRFS), a software system used by the RFCs for hydrologic forecasting, includes an automatic optimization program (OPT3) to aid in model calibration. The OPT3 program is not used operationally by the majority of RFC hydrologists who perform calibration studies. Lack of success with the traditional single - step, single-criterion automatic calibration approach has left hydrologists more comfortable employing a manual step-by-step process to estimate parameters. This study develops a Multistep Automatic Calibration Scheme (MACS), utilizing OPT3, for the river forecasting models used by the RFCs: the Sacramento Soil Moisture Accounting (SAC-SMA). and SNOW-17 models. Sixteen parameters are calibrated in three steps, replicating the progression of manual calibration steps used by NWS hydrologists. MACS is developed by minimizing different objective functions for different parameters in a step -wise manner. Model runs are compared using the MACS optimized parameters and the manually estimated parameters for six basins in the North Central River Forecast Center (NCRFC) forecast area. Results demonstrate that the parameters obtained via the MACS procedure generally yield better model performance than those obtained by manual calibration. The MACS methodology is a time-saving approach that can provide prompt model forecasts for NWS watersheds.
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Liu, Kun, and 刘琨. "Geochemical and geomicrobiological studies of the ammonium-rich aquifer-aquitard system in the Pearl River Delta, China." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2014. http://hdl.handle.net/10722/196494.
Full textAbstract:
An aquitard is not only a confining layer in the aquifer-aquitard system, but also a functional complex for nutrient reservation and microorganism inhabitation. Geochemical characteristics and geomicrobial processes in aquitards play an important role in groundwater quality, and should be well studied. The Pearl River Delta is dominated by clay-rich aquitards and was intensively influenced by Holocene transgression. In this thesis, the aquifer-aquitard system in the PRD was studied from various perspectives including geophysics, geochemistry and geomicrobiology. Sediment and groundwater samples were taken from representative locations in the PRD at different lithological units. Particle size distribution, computed axial tomography, optically stimulated luminescence dating and scanning electron microscopy were analyzed to understand the geophysical properties. Concentrations of major ions and abundances of environmental isotopes were measured for geochemical analysis. Bacterial 16S rRNA gene clone libraries were constructed to analyze microbial identifications and community structures in different strata. Gene abundances of anammox 16S and bacteria amoA in both sediment and groundwater samples were quantitatively analyzed with 15N isotope at the same depth.
The mixing process of seawater and river water was the dominant factor controlling the isotopic and chemical characterizes of groundwater in the system. Isotopic fractionation in the aquitards was majorly controlled by chemical and biological reactions other than diffusion. Chemical pattern in this system was mainly controlled by topography and sea level in the Holocene. Independent sedimentary centers of strong reducing environment were located in the depressions controlled by fault zones, and generated massive amount of pyrite minerals in the sediment and NH4+ in the groundwater. The sea level and depositional environment in the Holocene determined the physical structures of the sediment and seawater/river-water ratio in the estuary. Isotopic research also demonstrated that South Asia Monsoon was the major source of atmospheric precipitation in the PRD.
Bacterial species in the PRD sediment were identified. Canonical correspondence analysis between bacterial linages and environment factors showed that community structures were significantly modified by geological conditions. High bacterial diversity was observed in samples from the Holocene aquitard M1 and aquifer T1, while in the older aquitard M2 and basal aquifer T2, the bacterial diversity was much lower. Chloroflexi, γ-proteobacteria and δ-proteobacteria were the dominant phyla in the aquitard sediment. β-proteobacteria was the dominant phylum in sediment which was strongly influenced by fresh water. Anammox was the controlling biochemical process in microbial-derived ammonium loss, as demonstrated by gene abundance coupling with 15N isotope and ammonium concentration. The 16S gene abundance of anammox bacteria ranged from approximately 105 to 106 copies/g in the aquitard sediment, and ranged from 104 to 105 copies/g in aquifers. amoA gene abundance was 1-2 orders lower than anammox bacteria 16S in aquitard sediment, but in aquifers, the gene abundances of amoA and anammox 16S were similar. Interface between aquifer and aquitard was demonstrated as biochemically enhanced zone. The results of this study significantly benefited the understanding of geochemistry and microbiology in the aquifer-aquitard system, and showed directions for future work on geomicrobiology in aquitards.published_or_final_version
Earth Sciences
Doctoral
Doctor of Philosophy
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Nicholls, Daniel John. "The source and behaviour of fine sediment deposits in the river Torridge, Devon and their implications for salmon spawning." Thesis, University of Exeter, 2000. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.324034.
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Abbe, Timothy. "Patterns, mechanics and geomorphic effects of wood debris accumulations in a forest river system /." Thesis, Connect to this title online; UW restricted, 2000. http://hdl.handle.net/1773/6730.
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Boys, Craig Ashley, and n/a. "Fish-Habitat Associations in a Large Dryland River of the Murray-Darling Basin, Australia." University of Canberra. Resource, Environmental & Heritage Sciences, 2007. http://erl.canberra.edu.au./public/adt-AUC20070807.112943.
Full textAbstract:
Many aspects concerning the association of riverine fish with in-channel habitat remain
poorly understood, greatly hindering the ability of researchers and managers to address
declines in fish assemblages. Recent insights gained from landscape ecology suggest
that small, uni-scalar approaches are unlikely to effectively determine those factors that
influence riverine structure and function and mediate fish-habitat associations. There
appears to be merit in using multiple-scale designs built upon a geomorphologically-derived
hierarchy to bridge small, intermediate and large spatial scales in large rivers.
This thesis employs a hierarchical design encompassing functional process zones
(referred to hereafter as zones), reaches and mesohabitats to investigate fish-habitat
associations as well as explore patterns of in-channel habitat structure in one of
Australia's largest dryland river systems; the Barwon-Darling River.
In this thesis, empirical evidence is presented showing that large dryland rivers are
inherently complex in structure and different facets of existing conceptual models of
landscape ecology must be refined when applied to these systems. In-channel habitat
and fish exist within a hierarchical arrangement of spatial scales in the riverscape,
displaying properties of discontinuities, longitudinal patterns and patch mosaics. During
low flows that predominate for the majority of time in the Barwon-Darling River there
is a significant difference in fish assemblage composition among mesohabitats. There is
a strong association between large wood and golden perch, Murray cod and carp, but
only a weak association with bony herring. Golden perch and Murray cod are large
wood specialists, whereas carp are more general in there use of mesohabitats. Bony
herring are strongly associated with smooth and irregular banks but are ubiquitous in
most mesohabitats. Open water (mid-channel and deep pool) mesohabitats are
characterised by relatively low abundances of all species and a particularly weak
association with golden perch, Murray cod and carp. Murray cod are weakly associated
with matted bank, whereas carp and bony herring associate with this mesohabitat patch
in low abundance.
Nocturnal sampling provided useful information on size-related use of habitat that was
not evident from day sampling. Both bony herring and carp exhibited a variety of
habitat use patterns throughout the die1 period and throughout their lifetime, with
temporal partitioning of habitat use by juvenile bony herring and carp evident. Much of
the strong association between bony herring and smooth and irregular banks was due to
the abundance of juveniles (<100mm in length) in these mesohabitats. Adult bony
herring (>100mm length) occupied large wood more than smooth and irregular banks.
At night, juvenile bony herring were not captured, suggesting the use of deeper water
habitats. Adult bony herring were captured at night and occupjed large wood, smooth
bank and irregular bank. Juvenile carp (<200mm length) were more abundant at night
and aggregated in smooth and irregular banks more than any other mesohabitat patch.
Adult carp (>200mm length) occupied large wood during both day and night.
There is a downstream pattern of change in the fish assemblage among river zones, with
reaches in Zone 2 containing a larger proportion of introduced species (carp and
goldfish) because of a significantly lower abundance of native species (bony herring,
golden perch and Murray cod) than all other zones. In comparison, the fish assemblage
of Zone 3 was characterised by a comparatively higher abundance of the native species
bony herring, golden perch and Murray cod. A significant proportion of the amongreach
variability in fish assemblage composition was explained at the zone scale,
suggesting that geomorphological influences may impose some degree of top-down
constraint over fish assemblage distribution. Although mesohabitat composition among
reaches in the Barwon-Darling River also changed throughout the study area, this
pattern explained very little of the large-scale distribution of the fish assemblage, with
most of the variability in assemblage distribution remaining unexplained. Therefore,
although mesohabitat patches strongly influence the distribution of species within
reaches, they explain very little of assemblage composition at intermediate zone and
larger river scales. These findings suggest that small scale mesohabitat rehabilitation
projects within reaches are unlikely to produce measurable benefits for the fish
assemblage over intermediate and large spatial scales in the Barwon-Darling River. This
indicates the importance taking a holistic approach to river rehabilitation that correctly
identifies and targets limiting processes at the correct scales.
The variable nature of flow-pulse dynamics in the Barwon-Darling River creates a
shifting habitat mosaic that serves to maintain an ever-changing arrangement of habitat
patches. The inundation dynamics of large wood habitat described in this thesis
highlights the fragmented nature of mesohabitat patches, with the largest proportion of
total in-channel large wood remaining unavailable to fish for the majority of the time.
At low flows there is a mosaic of large wood habitat and with increasing discharge more
potential large wood habitat becomes available and does so in a complex spatial
manner. What results in this dryland river is a dynamic pattern of spatio-temporal
patchiness in large wood habitat availability that is seen both longitudinally among
different river zones and vertically among different heights in the river channel. Water
resource development impacts on this shifting habitat mosaic.
Projects undertaking both fish habitat assessment and rehabilitation need to carefully
consider spatial scale since the drivers of fish assemblage structure can occur at scales
well beyond that of the reach. Fish-habitat associations occurring at small spatial scales
can become decoupled by process occurring across large spatial scales, making
responses in the fish assemblage hard to predict. As rivers become increasingly
channelised, there is an urgent need to apply research such as that conducted in this
thesis to better understand the role that in-channel habitats play in supporting fish and
other ecosystem processes. Habitat rehabilitation projects need to be refined to consider
the appropriate scales at which fish assemblages associate with habitat. Failure to do so
risks wasting resources and forgoes valuable opportunities for addressing declines in
native fish populations. Adopting multi-scalar approaches to understanding ecological
processes in aquatic ecosystems, as developed in this thesis, should be a priority of
research and management. To do so will enable more effective determination of those
factors that influence riverine structure and function at the approariate scale.
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Abolghasemi, Riseh Hamideh. "Optimization of the Kootenay River hydroelectric system with a linear programming model." Thesis, University of British Columbia, 2008. http://hdl.handle.net/2429/5792.
Full textAbstract:
The main objective of hydroelectric system optimization is to determine an operating policy for
the best use of available resources. In order to find the optimum policy one should decide on the
trade-off between the marginal value of water in the reservoirs and the amount of electricity
produced electricity. The variability of natural inflows along with local and environmental
limitations and special procedures and regulations, makes the decision making process more
challenging for an operation planner of a reservoir system.
The region considered in this study is the Kootenay River System and it includes five
hydroelectric plants and a canal. The main storage reservoir in this system is the Kootenay Lake,
which is the largest natural lake in British Columbia, Canada. The operation of the Kootenay
system is complex because day-to-day operation decisions should satisfr all existing rules and
water treaties and agreements in the area. In addition, a power generation schedule should take
advantage of electricity markets and meet local load demands.
This thesis developed a Linear Programming model to optimize the operation of the Kootenay
system on daily timesteps for studies up to one year. Due to the operational complexities, the
Kootenay system was not included in the optimization models developed at B.C Hydro (BCH).
This model can be an extension to the existing “STOM” (Short Term Optimization Model) and
Generalized Optimization Model “GOM”, which have been successfully adopted by BCH to
optimize the daily operation of its plants. This is the first optimization model for the operation of
Kootenay System and was developed in accordance with all the existing international treaties
and special constraints on this system.
Results obtained using the model have indicated that this model can successfully optimize the
operation of the Kootenay system. Comparison of this model to the current operation method
showed that with respect to all system’s constraints and value of water, the optimization model
can yield a higher value of electricity generation and it is expected that it will be added to the set
of tools used by the system operation engineers for their daily operations.