Thesis (M.S.)--Rutgers University, 2008. / "Graduate Program in Geography." Includes bibliographical references (p. 119-124).

This master thesis deals with the influence of temporal distribution of precipitation on hydrological characteristics of the rainfall-runoff process. The practical part of the thesis was carried out on the drainage basin Volšovka. In the theoretical part, the origin, division, and temporal distribution of rainfall is described, as well as surface runoff and some chosen hydrological characteristics of flow-off. Moreover the work deals with hydrological simulation, there is also described in further detail the rainfall-runoff model HEC-HMS, which is furthermore used in the practical part of this thesis. In the practical part, the characteristics of the area of interest is introduced. Next is described the preparation of the rainfall data with the use of DES_RAIN programme, also creation of the digital model of the terrain in the ArcGIS programme and the preparation of hydrological model in HEC-HMS model. In the conclusion of the thesis, the flow capacities of the closure profile of Volšovka were simulated, as well as other particular closure profiles of the catchment area. There were 16 simulations carried out, which were evaluated on the basis of the peak flow capacities and the time of culmination.

In this diploma thesis I follow my bachelor thesis and generally deal with drainage systems and their influence on a water regime of a river basin. In the theoretical part, I describe issues associated with the drainage systems, whether their impact on the landscape or generally how they affect the water regime. Further I explain the water runoff in the landscape from its sorting and description of various runoff types up to the methods of its separation. Basic methods of the separation are described here, as well as separation with the use of digital filters. In the last part, these methods are used for separations of the runoff at selected river basins which are described in detail in the chapter named "material". For further comparison and results, the calculation of the runoff coefficient, analysis of precipitation and runoff events and analysis of subsidence branches were used. The chapter "results and discussion" where all results of this thesis are explained has been placed at the end.

Orientador: José Euclides Stipp Paterniani / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Civil, Arquitetura e Urbanismo / Made available in DSpace on 2018-08-23T10:41:16Z (GMT). No. of bitstreams: 1 Cavalhieri_CaioPompeu_M.pdf: 3818458 bytes, checksum: 75bf1f2391a40c8e0f8f527257f97c8a (MD5) Previous issue date: 2013 / Resumo: Idealizadas para prevenir e controlar problemas associados à intensificação de processos erosivos, cercas-silte ou silt-fences são cada vez mais comuns em canteiros de obra. Feitas com mantas de geotêxtil estruturadas sob a forma de barreiras verticais, essas cercas promovem a detenção das águas pluviais que escoam sobre a superfície do terreno e, dessa maneira, favorecem a remoção de sedimentos em suspensão no runoff por meio da combinação dos efeitos de sedimentação e filtração. Assim, considerando-se a relevância que as mantas de geotêxtil têm sobre a qualidade de todo o processo, este estudo avaliou o desempenho de geotêxteis não-tecidos em relação à remoção de sólidos suspensos. Para tanto, experimentos foram realizados em laboratório e, com o intuito de aproximar os ensaios ainda mais da realidade, os experimentos foram feitos com: (a) mantas em duas situações distintas (sem nenhum tipo de uso e retirada de um canteiro de obra após dois anos de uso contínuo como cerca-silte); (b) solo coletado no mesmo canteiro de onde veio o geotêxtil usado (para compor o runoff dos ensaios em média com 800 UNT); (c) escoamento do runoff na direção horizontal; e, por fim, (d) parâmetros de ensaio baseados em critérios de projeto e também na equação de chuva da área mais próxima da obra de onde vieram as amostras de solo e geotêxtil usado. De maneira geral, os dois tipos de geotêxtil (novo e usado) favoreceram a redução de sólidos em suspensão durante os ensaios, embora esse efeito tenha sido estatisticamente mais significativo na manta retirada da obra. Além disso, valores de turbidez menores do que 40 UNT (parte inferior aos 5,0 UNT preconizados para consumo humano) estiveram associados a taxas de escoamento relativamente baixas (menores do que 20 mm/min). Entretanto, há que se considerar que, em determinados contextos, baixas taxas de escoamento também têm potencial para gerar repercussões indesejáveis. Daí a importância de se contar com a boa fundamentação de projetos, atividades de instalação e serviços de manutenção, de maneira que os resultados esperados sejam compatíveis com os obtidos em situações reais / Abstract: Developed to prevent and control problems associated with the intensification of erosion, silt or silt-fences-fences are increasingly common in construction sites. Made with geotextiles structured in the form of vertical barriers, these fences detain rainwater runoff and, thus, promote the removal of suspended sediments through sedimentation and filtered. Considering the relevance geotextiles have on the quality of the entire process, this study evaluated the performance of non-woven geotextiles regarding the removal of suspended solids. Therefore, experiments were performed in the laboratory and were made with: (a) blankets in two distinct situations (without any use and removed from a construction site after two years of continuous use as fence-silt); (b) soil collected in the same plot where the geotextile was used as silt-fence (to compose the runoff tests averaged 800 UNT); (c) runoff flow in the horizontal direction; and finally, (d) test parameters based on design criteria and also the rain equation of the closest area to the work from which the samples of soil and geotextile came from. In general, the two types of geotextile (used and new) promoted reduction of suspended solids during the tests, although this effect was statistically significant over the blanket removal of the work. Furthermore, turbidity values lower than 40 NTU (5.0 NTU at the bottom recommended for human consumption) were associated with relatively low flow rates (less than 20 mm / min). However, it is necessary to consider that, in certain contexts, low flow rates also have the potential to generate undesirable impacts. Hence the importance of relying on consistent projects, activities of installation and maintenance services, so that the expected results can be consistent with those obtained in real situations / Mestrado / Saneamento e Ambiente / Mestre em Engenharia Civil

The study presents the results of applying two isolated event, constant runoff proportion, conceptual models to a range of catchments drawn from various climatic and physiographic regions of South Africa and the USA. The models can be operated in either lumped or semi-distributed modes. The research progressed through the following stages. The initial stage involved the calibration of both models on two sets of catchments so that an initial evaluation of the performance of the models could be carried out and any deficiencies in the model structure identified, and where practical, corrected. The models were then calibrated on a further 8 catchments. An important result of the calibration is that for both models to produce reasonably acceptable simulations, at least one parameter has to vary between storms on the same catchment to account for variations in storm or antecedent moisture characteristics. The next stage consisted of compiling quantitative descriptions of the physical characteristics of the catchments and rainfall events and an attempt to relate the calibrated parameter values to relevant physical characteristics for the purpose of estimating parameter values when calibration is not possible. Despite the difficulties encountered in quantifying some of the hydrological characteristics the general trends exhibited by many of the relationships are encouraging and the format of the combinations of physical variables used, do make sense with respect to the original parameter conceptualisations. The relationships between storm characteristics and parameters of both models are less satisfactory. There is a high degree of scatter and the between-catchment variation in the form of the relationships, indicates that the derived relationships are likely to be of little use for parameter estimation purposes. The final stage involved a validation exercise in which new parameters were estimated from the physical variable-parameter relationships for all the catchments previously used, as well as a further four. The new parameters were used to re-simulate all the storms and comparison of these results were made with the original calibration results. Both models produced poor results and are unlikely to give reliable results where calibration is not possible. The parameter relationships for the parameters related to storm characteristics are so catchment specific that transfer to other areas will produce unpredictable results. Foot note:- For compatability with computer printouts decimal full stops are used in the format of real numbers in tables etc

Athabasca River Basin is located in an area which is affected by many factors. During the last century, the global warming manifests here, resulting primarily into increasing temperatures and glaciers melting in the headwaters area. Much of the middle reaches watershed is used for agriculture, for irrigation of which water from the Athabasca River is pumped. In recent years, controversial development of bituminous sands mining is carried out in the basin. Although it represents a real energy source, the mining requires large amounts of water, which is largely drawn from the Athabasca River. The work therefore analyzes the runoff change in the upper, middle and lower reaches during the last forty years. Along with the time series air temperature changes and precipitation totals, which can also explain runoff changes, are analyzed. Powered by TCPDF (www.tcpdf.org)

Surface depressions are important topographic features, which affect overland flow, infiltration, and other hydrologic processes. Specifically, depressions undergo filling-spilling-merging-splitting processes under natural rainfall conditions, featuring discontinuity in hydrologic connectivity and variability in contributing area. However, a constant and time-invariant contributing area is often assumed in traditional hydrologic modeling, and consequently, the real threshold-controlled overland flow dynamics cannot be captured. The overall goal of this dissertation research is to improve hydrologic modeling, especially for depression-dominated areas, by quantifying the hydrologic effects of depressions. The specific objectives are to analyze the hydrotopographic characteristics of depressions and identify the intrinsic relationships of hydrologic variables, develop new modeling methods to simulate the depression-oriented dynamics in overland flow and variations in contributing area, and reveal the influence of spatially distributed depressions on the surface runoff generation and propagation processes. To achieve these objectives, three studies were conducted: (1) the frequency distribution of depression storage capacities was determined and a puddle-based unit (PBU)-probability distribution model (PDM) was developed; (2) the intrinsic changing patterns of contributing area and depression storage were identified, based on which a new depression-oriented variable contributing area (D-VCA) model was developed; and (3) a modified D-VCA (MD-VCA) model was further developed by introducing a depressional time-area zone scheme and a new variable contributing area-based surface runoff routing technique to account for the spatial distribution of depressions. These three models (PBU-PDM, D-VCA, and MD-VCA) were evaluated through the applications to depression-dominated watersheds in North Dakota, and simulation results demonstrated their capabilities in simulating the variations of contributing areas and threshold-controlled overland flow dynamics. In addition, these three studies emphasized the important roles of depressions in the evolution of contributing areas as well as surface runoff generation and propagation. Without considering the spatial distribution of depressions, the formation of contributing area and the timing and quantity of runoff contributions cannot be characterized.

No description available.

Due to the combined effect of intense rainfall events together with the expected impact of climate change, this will put pressure on the existing and future infrastructure for storm water management. One of the challenges related to this is the combined sewer system which is still operating in large areas of many cities worldwide. In Stockholm, combined sewer represents around 50% of the total sewer pipe length. In a Combined sewer system, once the conveyed discharge exceeds the system capacity, the system overflows, which can result in a diverse range of health and environmental problems. The cause of overflow has been strongly linked to runoff from intense rainfall events. Therefore, a key proposal to overcome this problem is to disconnect runoff from hard surfaces. This research aims to investigate the impact of applying a rainwater harvesting (RWH) and reuse system to collect runoff water from roof surfaces in areas with combined sewer system. A simulation water balance model for a rooftop RWH system was developed and two reuse purposes were considered, which entails toilet flushing and garden irrigation within the property. The study area consists of one building block within Kungsholmen area in Stockholm. The obtained results indicate that applying such systems can reduce runoff to the sewer system. Toilet flushing reuse shows a higher reduction impact on sewer flow than the use for irrigation. Toilet flushing reuse reduces annual runoff volumes to sewer in a range of 49.5% - 93.4% while irrigation provided reduction in a range of 11.6% - 26.3%. Regarding number of times that overflow from the combined sewer system occurs, toilet flushing reuse demonstrated reduction of 40% - 100% while 20% to 60% was reduced by irrigation reuse. For overflow volume, a reduction rate of 11% to 100% was reached through toilet flushing in contrast to 9% to 43% reduction from irrigation reuse. 19% to 37% of toilet flushing water demand was covered by the tank, while arange of 48% to 100% was covered for irrigation demand. All these parameters were found to be sensitive to change in tank size where increasing the size result in higher flow reduction rates. When considering implementing a reuse system, it is important to consider the applicability of RWH and reuse within the specific property. In areas that are under development, either of the two reuses can be considered depending on local conditions. However, in already built up area it is difficult to introduce a system that requires significant adjustment to existing pipe networks, such as reuse systems for toilet flushing. Systems for outdoor irrigation are possible to implement in most situations. When it comes to tank size, the optimal size will depend on the intended reuse, the catchment area and the objective of the system. For example, if the main objective is to reduce potable water consumption, a smaller tank can be used compared to where the main objective is to reduce sewer overflow. Hence, when considering implementing a rainwater reuse systems, each project will need to consider the local conditions as well as the individual objectives when determining the optimal reuse purpose and tank size. A cost-benefit analysis should also be considered when determining the optimal tank size for the intended use.

No description available.