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There is overwhelming scientific evidence that shows the temperature of the Earth's atmosphere is rising at an unprecedented rate. This is attributed to increased levels of greenhouse gas emissions, a large proportion of which originates from anthropogenic combustion of carbon-based fossil fuels for energy. There is therefore a strong argument for the increased role of less environmentally damaging, low carbon energy sources including renewable energy technologies. Run-of-river hydropower is one such renewable energy option, considered more environmentally benign than traditional hydropower which requires the construction of large dams to create a reservoir. The aim of this study was to develop a model to search for, and map, economically viable run-of-river hydropower resource that can function on any global catchment of any size. Development and testing of the model was conducted on China's 2 million km2 Yangtze River drainage basin, the third longest river in the world and a rich landscape for hydropower. A gridded, distributed hydrological model was developed integrating high-resolution meteorological datasets and a digital elevation model (DEM). Using the model, the surface hydrology of the Yangtze catchment was simulated at a timestep of 6 minutes to obtain the mean daily surface runoff for every day from the beginning of 1979 to the end of 2007. Observed river flow data from sub-catchments of the Yangtze were used to calibrate the model by differential optimisation, an evolutionary computation technique. Validation was carried out on a 1.6 million km2 sub-catchment resulting in a mean objective function of 0.95 (where a perfect fit would be 1.0) across 8 objective functions commonly used in hydrology. Catchment wide mean daily runoff data was used to develop flow duration curves across the catchment river network. Virtual power stations were constructed at each river cell, iteratively testing differing scheme configurations, and costed using the RETScreen methodology. A best performing hydropower network was determined by a conflict algorithm, designed to prioritise high profit schemes and to remove lower performing and conflicting schemes. This resulted in a potential run-of-river installed capacity across the Yangtze catchment of 103GW (at 10% discount rate), generating 394TWh per annum. This model would be a valuable tool in finding optimal locations for future hydropower resource.

Thesis (MEng)--Stellenbosch University, 2012. / ENGLISH ABSTRACT: Sedimentation and the effects it has on turbine blades was the primary problem identified in run-of-river (RoR) hydropower schemes. Sedimentation in RoR hydropower schemes also increases trash rack blockage and reduces energy output in the long-term. Damage occurs to all underwater parts that come into contact with sediment. The main concern is sediment passing through the hydropower intake and causing turbine damage. The reason for the abrasion and cavitation of turbine blades is increased sediment loads in river channels. This problem can be overcome in two ways. The first is the use of existing lakes or reservoir storage upstream as natural sand traps, and the second is by investigating the three features associated with river bend diversion, which are: the optimum diversion location in a river bend to minimise the abstraction of sediment, the optimum diversion structure angle to limit coarse sediment diversion, and the sediment load diverted through the intake. The first objective of the research was investigated by construction of a physical model of a curved river channel to determine the location of the deepest scour forming on the outside of the bend. The second objective was to test the diversion orientation to maximize the local scour and thereby limiting sediment diversion at the intake. A third objective was to compare mathematical 2D model simulated scour results with the findings of the laboratory tests to evaluate the reliability of the numerical model predictions. Finally different diverted discharge ratios were tested with different intake setups in the physical model, to evaluate the sediment load diverted. . The first experiment in the curved laboratory channel was to predict where the deepest scour takes place without a diversion structure. This was then followed by placing a diversion structure at the maximum scour position, retrieved from experiment one, and by angling the structure with reference to the flow direction. The flow direction vector was placed as a tangent to the bend and orientated at angles of 0⁰, 30⁰, 45⁰ and 60⁰ into the bend direction. The optimum diversion location was found to be positioned on the outside of the bend, approximately 60⁰ into the channel bend. The final position of maximum scour in a 90⁰ bend corresponds with the Sediment Committee and the Chinese Hydraulic Engineering Societies (1992) prediction of 60⁰ into the bend. The optimal diversion had a 30⁰ angle to the flow direction, as this presented the most efficient and effective scouring in front of the model intake. Numerical simulations were performed with the CCHE 2D (hydrodynamics and sediment dynamics) modelling program. The numerical results were compared to the physical results to validate CCHE as a beneficial simulation tool. It was found that the numerical model predicted the scour depths at the intakes tested with an accuracy of 43.8%, which is within the accuracy range of the sediment transport equation used by the numerical model. The final experiment was the diversion of sediment with different intake level heights and discharges. It was evident from the results that low sediment diversion ratios were achieved with a diverted discharge ratio of 50% or less. The intake elevation highest above the channel bed diverted the least sediment. The interrelationship between Diverted Discharge Ratio (DDR), Diverted Froude number Ratio (DFrR) and Diverted Sediment load Ratio (SDR) was established in the study. It is recommended that RoR schemes have sand traps downstream of the diversion structures and that turbines are coated with HVOF to overcome the power loss arising due to the excessive erosion of hydro turbines. / AFRIKAANSE OPSOMMING: Sedimentasie en die invloed wat dit het op turbines was die primêre probleem geïdentifiseer in “run-of-river” (RoR) hidrokrag-skemas. Die sediment wat saam met die water uit ‟n rivier uitgekeer word beskadig die inlaatrooster en verlaag kragopwekking in die langtermyn. Skade word aangerig aan alle onderwatertoerusting en masjinerie wat aan sediment blootgestel word. Die grootste probleem tydens die uitkering van water is die growwe sediment wat daarmee deur die onttrekking inlaat gaan en turbineskade veroorsaak. Soos wat die sedimentlading in die rivier drasties toeneem, sal afslyting en kavitasie van turbinelemme meer gereeld voorkom. Dié probleem kan op twee maniere beperk word. Die een is die gebruik van bestaande opgaardamme stroomop, en die tweede is deur die ondersoek van drie kenmerke van rivierdraaie en uitkeringstrukture, bv. die optimale uitskurings posisie in 'n rivierdraai (sonder ʼn struktuur) om die diepste uitskuringposisie op die buitekant van die draai te bepaal, die optimale uitkeringsstruktuuroriëntasie wat maksimum uitskuring verseker en die sediment uitkering beperk, en die lading van sedimentonttrekking deur die inlaat. Die eerste doelwit van die navorsing is ondersoek deur ʼn fisiese model te bou van ʼn kronkelkanaal en te bepaal waar die diepste uitskring plaasvind op die buitekant van die draai. Die tweede doelwit van die studie was om die optimale uitkeringshoek te bepaal vir 'n uitkeringstruktuur sodat die uitskuring by die inlaat ʼn maksimum is om die uitkering van sediment te beperk. ʼn Derde doelwit was om die akkuraatheid van ʼn wiskundige model se uitskuring voorspelling te toets teen die waargenome laboratorium resultate. Die finale doelwit was om vir verskillende inlaatontwerpe, rivier- en uitkeervloeie die sedimentladings wat uitgekeer word te ondersoek. Die eerste eksperiment in die kronkelende kanaal was voorberei om die optimale uitskuring in die draai te bepaal. Dit is gevolg deur toetse met uitkeerstrukture by die maksimum uitskurings posisie te plaas en die hoek van die struktuur dan te verander met verwysing na die vloeirigting. Die vloeirigting vektor was as 'n raaklyn geplaas op die kanaal draai en georiënteer met hoeke: 0⁰, 30⁰, 45⁰ en 60⁰, in die rigting van die draai. Die optimale uitskurings posisie was aan die buiterand van die kanaal draai gevind, ongeveer 60⁰ in die draai in. Die maksimum uitskuur posisie van 'n 90⁰ kanaal draai stem ooreen met SC en CHES (1992) se resultaat van 60⁰ in die draai in. Daar was ook genoegsame bewyse dat 'n optimale uitkeerwerke oriëntasie van 30⁰ die doeltreffendste en effektiefste uitskuring sal gee. Numeriese simulasies is deur middel van 'n twee dimensionele wiskundige model CCHE 2D (hidro- en sedimentdinamika) uitgevoer. Die numeriese resultate was vergelyk met die laboratoriumresultate om die CCHE program te verifieer as 'n voordelige simulasie program. Daar is gevind dat die wiskundige model die uitskuurdieptes by die inlate met ʼn akkuraatheid van 43.8 % voorspel, wat binne die akkuraatheid is van die sedimentvervoervergelyking wat deur die numeriese model gebruik word. Die finale eksperiment was die uitkering van sediment met verskillende inlaathoogtes en uitkerings sedimentladings. Uit die toetse was dit duidelik dat 'n lae sediment uitkeerverhouding behaal kan word met 'n uitkeerverhouding van 50% en minder. Verdere waarnemings het ook gewys dat die inlaathoogte van die uitkeerstruktuur met die optimale resultate die hoogste bokant die rivierbedding was. Die verwantskap tussen die uitgekeerde deurstromingverhouding, die uitgekeerde Froude getal verhouding en die uitgekeerde sedimentlading is bepaal in die navorsing. Dit word aanbeveel dat sandvangkanale stroomaf van uitkeerwerke geplaas word en dat turbines met HVOF as bedekkingsmateriaal beskerm word om kragverliese as gevolg van buitensporige erosie van die turbines te voorkom.

Submitted by Ronaldo Natalino Ciciliato CICILIATO (ronaldociciliato_eco@yahoo.com.br) on 2016-07-26T01:53:04Z No. of bitstreams: 1 TESE FINAL ARQUIVAMENTO SISTEMA UNESP...25 de julho 2016 CICILIATO,RN..PDF: 25946096 bytes, checksum: 908b1b1548892d4d40414309e085990a (MD5) / Approved for entry into archive by Felipe Augusto Arakaki (arakaki@reitoria.unesp.br) on 2016-07-29T12:50:21Z (GMT) No. of bitstreams: 1 ciciliato_rn_dr_prud.pdf: 25946096 bytes, checksum: 908b1b1548892d4d40414309e085990a (MD5) / Made available in DSpace on 2016-07-29T12:50:21Z (GMT). No. of bitstreams: 1 ciciliato_rn_dr_prud.pdf: 25946096 bytes, checksum: 908b1b1548892d4d40414309e085990a (MD5) Previous issue date: 2016-06-20 / Este trabalho analisou os impactos socioambientais provocados pela construção da hidrelétrica de Capivara ou Engenharia Mackenzie no Rio Paranapanema, estado de São Paulo, Brasil. Desde a formação do reservatório da hidrelétrica de Capivara em 1977, grandes transformações ocorreram no entorno do lago. Embora apresentasse pequena concentração populacional e relativa distância dos grandes centros urbanos, que provocassem maiores impactos ambientais, apresentou à formação de penínsulas, de áreas alagadas, lagoas marginais, várzeas, alagamento de remanescentes de vegetação primitiva, além de um processo de ocupação irregular em suas margens. A evolução da agricultura na região da tradicional cafeicultura para as culturas comerciais da soja, trigo e milho e cana de açúcar, levou esses cultivos a serem praticados junto às áreas de alagamento do lago de Capivara, acelerando os processos erosivos dos solos, assoreamento, lixiviação, além da descarga de agroquímicos carregados pelas chuvas diretamente nas águas do lago. Foram realizados estudos de campo, tanto em terra como com a navegação de áreas de difícil acesso, onde foram identificadas erosões marginais de grande impacto devido à ocupação irregular de Áreas de Preservação Permanente pela pecuária, construções irregulares, loteamentos, ranchos de lazer e atividades ligadas ao turismo balneário. Os dados levantados nesta pesquisa indicaram haver mudanças e transformações na paisagem regional, sobretudo nas Áreas de Preservação Permanente, devido à reconfiguração das margens do Rio Paranapanema, entre os Estados de São Paulo e Paraná. A partir disso pode- se afirmar que há a necessidade de atuação do poder público visando à adequação dos usos e da ocupação das áreas de influência direta do reservatório de Capivara, no rio Paranapanema, buscando minimizar e manter, do ponto de vista ambiental, a biodiversidade, os solos, a água e seu uso econômico racional. / This study analyzed the environmental impacts caused by the construction of hydroelectric Capybara or Mackenzie Engineering in Rio Paranapanema, São Paulo, Brazil. Since the formation of Capivara hydroelectric reservoir in 1977, great changes occurred in the vicinity of the lake. Though having small population density and relative distance from large urban centers, which provoked major environmental impacts, presented to the formation of peninsulas of wetlands, lagoons, floodplains, remnants of flooding of primitive vegetation, and an irregular settlement process in their margins. The development of agriculture in the traditional coffee growing region for commercial soybean, wheat and corn and sugar cane, took these crops to be carried along the flooded areas of Capybara lake, accelerating the erosion of soil, silting, leaching in addition to the agrochemical discharge carried by rain directly on the lake waters. Field studies were carried out, both on land and in the navigation areas of difficult access, where marginal erosions of great impact were identified due to the illegal occupation of Permanent Preservation Areas in livestock, irregular buildings, housing developments, leisure ranches and related activities the spa tourism. The data collected in this study indicated that there shifts and changes in the regional landscape, particularly in Permanent Preservation Areas, due to the reconfiguration of the Paranapanema River banks, between the states of São Paulo and Paraná. From this it can be stated that there is need for action of public authorities to the suitability of the use and occupation of areas of direct influence of the Capivara reservoir on the river Paranapanema, seeking to minimize and maintain the environmental point of view, biodiversity, soil, water and their rational economic use.