Calibration of structure in a distributed forecasting model for a semiarid flash flood: dynamic surface storage and channel roughness

Flash floods pose a significant danger for life and property. Unfortunately, in arid and semiarid environment the runoff generation shows a complex non-linear behavior with a strong spatial and temporal non-uniformity. As a result, the predictions made by physically-based simulations in semiarid areas are subject to great uncertainty, and a failure in the predictive behavior of existing models is common. Thus better descriptions of physical processes at the watershed scale need to be incorporated into the hydrological model structures. For example, terrain relief has been systematically considered static in flood modelling at the watershed scale. Here, we show that the integrated effect of small distributed relief variations originated through concurrent hydrological processes within a storm event was significant on the watershed scale hydrograph. We model these observations by introducing dynamic formulations of two relief-related parameters at diverse scales: maximum depression storage, and roughness coefficient in channels. In the final (a posteriori) model structure these parameters are allowed to be both time-constant or time-varying. The case under study is a convective storm in a semiarid Mediterranean watershed with ephemeral channels and high agricultural pressures (the Rambla del Albujón watershed; 556 km 2 ), which showed a complex multi-peak response. First, to obtain quasi-sensible simulations in the (a priori) model with time-constant relief-related parameters, a spatially distributed parameterization was strictly required. Second, a generalized likelihood uncertainty estimation (GLUE) inference applied to the improved model structure, and conditioned to observed nested hydrographs, showed that accounting for dynamic relief-related parameters led to improved simulations. The discussion is finally broadened by considering the use of the calibrated model both to analyze the sensitivity of the watershed to storm motion and to attempt the flood forecasting of a stratiform event with highly different behavior.

Reliability Assessment of a Storm Water Drain Network

Most of the cities in India are undergoing rapid development in recent decades, and many rural localities are undergoing transformation to urban hotspots. These developments have associated land use/land cover (LULC) change that effects runoff response from catchments, which is often evident in the form of increase in runoff peaks, volume and velocity in drain network. Often most of the existing storm water drains are in dilapidated stage owing to improper maintenance or inadequate design. The drains are conventionally designed using procedures that are based on some anticipated future conditions. Further, values of parameters/variables associated with design of the network are traditionally considered to be deterministic. However, in reality, the parameters/variables have uncertainty due to natural and/or inherent randomness. There is a need to consider the uncertainties for designing a storm water drain network that can effectively convey the discharge. The present study evaluates performance of an existing storm water drain network in Bangalore, India, through reliability analysis by Advance First Order Second Moment (AFOSM) method. In the reliability analysis, parameters that are considered to be random variables are roughness coefficient, slope and conduit dimensions. Performance of the existing network is evaluated considering three failure modes. The first failure mode occurs when runoff exceeds capacity of the storm water drain network, while the second failure mode occurs when the actual flow velocity in the storm water drain network exceeds the maximum allowable velocity for erosion control, whereas the third failure mode occurs when the minimum flow velocity is less than the minimum allowable velocity for deposition control. In the analysis, runoff generated from subcatchments of the study area and flow velocity in storm water drains are estimated using Storm Water Management Model (SWMM). Results from the study are presented and discussed. The reliability values are low under the three failure modes, indicating a need to redesign several of the conduits to improve their reliability. This study finds use in devising plans for expansion of the Bangalore storm water drain system. (C) 2015 The Authors. Published by Elsevier B.V.

溶蚀岩体渗透水力学特性研究

Seepage control in karstic rock masses is one of the most important problems in domestic hydroelectric engineering and mining engineering as well as traffic engineering. At present permeability assessment and leakage analysis of multi-layer karstic rock masses are mainly qualitative, while seldom quantitative. Quantitative analyses of the permeability coefficient and seepage amount are conducted in this report, which will provide a theoretical basis for the study of seepage law and seepage control treatment of karstic rocks. Based on the field measurements in the horizontal grouting galleries of seepage control curtains on the left bank of the Shuibuya Hydropower Project on the Qingjiang river, a hydraulic model is established in this report, and the computation results will provide a scientific basis for optimization of grouting curtain engineering. Following issues are addressed in the report. (1) Based on the in-situ measurements of fissures and karstic cavities in grouting galleries, the characteristics of karstic rock mass is analyzed, and a stochastic structural model of karstic rock masses is set up, which will provide the basis for calculation of the permeability and leakage amount of karstic rock mass. (2) According to the distribution of the measured joints in the grouting galleries and the stochastic results obtained from the stochastic structural model of karstic rock mass between grouting galleries, a formula for computation of permeability tensor of fracturing system is set up, and a computation program is made with Visual Basic language. The computation results will be helpful for zoning of fissured rock masses and calculation of seepage amount as well as optimization of seepage control curtains. (3) Fractal theory is used to describe quantitatively the roughness of conduit walls of karstic systems and the sinuosity of karstic conduits. It is proposed that the roughness coefficient of kastic caves can be expressed by both fractal dimension Ds and Dr that represent respectively the extension sinuosity of karstic caves and the roughness of the conduit walls. The existing formula for calculating the seepage amount of karstic conduits is revised and programmed. The seepage amount of rock masses in the measured grouting galleries is estimated under the condition that no seepage control measures are taken before reservoir impoundment, and the results will be helpful for design and construction optimization of seepage curtains of the Shuibuya hydropower project. This report is one part of the subject "Karstic hydrogeology and the structural model and seepage hydraulics of karstic rock masses", a sub-program of "Study on seepage hydraulics of multi-layer karstic rock masses and its application in seepage control curtain engineering", which is financially supported by the Hubei Provincial key science and technology programme.

Avaliação de características morfométricas na relação solo-superfície da Bacia Hidrográfica do Córrego Rico, Jaboticabal (SP)

Com a análise das características morfométricas procura-se entender a relação solo-superfície, em decorrência dos processos erosivos sobre estruturas e litologias variadas. Neste trabalho, objetivou-se avaliar as características morfométricas do padrão de drenagem e do relevo em microbacias hidrográficas de 2ª ordem de magnitude, em Latossolo Vermelho-Escuro e Argissolo Vermelho-Amarelo, com vistas ao planejamento agroambiental da Bacia Hidrográfica do Córrego Rico, município de Jaboticabal, SP. O estudo foi baseado em fotografias aéreas, pancromáticas, verticais na escala 1:35.000 da região administrativa de Ribeirão Preto. Com técnicas de fotointerpretação, foram traçadas a rede de drenagem e respectivas microbacias hidrográficas, onde as variáveis selecionadas foram determinadas. As classes de risco de degradação, resultando no uso potencial do solo, foram determinadas de acordo com o coeficiente de rugosidade. As características do padrão de drenagem e do relevo repercutiram no comportamento hidrológico e litológico das microbacias hidrográficas, possibilitando a diferenciação entre as unidades de solos. A densidade de drenagem e a amplitude altimétrica foram as características que mais contribuíram para o poder discriminatório na relação solo-superfície. Na análise conjunta do potencial de uso do solo, verificou-se, principalmente, adequação para agricultura nos Latossolos e pecuária e, ou, reflorestamento nos Argissolos.

Model to increase the lateral line length of drip irrigation systems

Non-pressure compensating drip hose is widely used for irrigation of vegetables and orchards. One limitation is that the lateral line length must be short to maintain uniformity due to head loss and slope. Any procedure to increase the length is appropriate because it represents low initial cost of the irrigation system. The hypothesis of this research is that it is possible to increase the lateral line length combining two points: using a larger spacing between emitters at the beginning of the lateral line and a smaller one after a certain distance; and allowing a higher pressure variation along the lateral line under an acceptable value of distribution uniformity. To evaluate this hypothesis, a nonlinear programming model (NLP) was developed. The input data are: diameter, roughness coefficient, pressure variation, emitter operational pressure, relationship between emitter discharge and pressure. The output data are: line length, discharge and length of the each section with different spacing between drippers, total discharge in the lateral line, multiple outlet adjustment coefficient, head losses, localized head loss, pressure variation, number of emitters, spacing between emitters, discharge in each emitter, and discharge per linear meter. The mathematical model developed was compared with the lateral line length obtained with the algebraic solution generated by the Darcy-Weisbach equation. The NLP model showed the best results since it generated the greater gain in the lateral line length, maintaining the uniformity and the flow variation under acceptable standards. It had also the lower flow variation, so its adoption is feasible and recommended.

Model to design drip hose lateral line using two spacing between emitters

The use of non-pressure compensating drip hose in horticultural and annual cycle fruits is growing in Brazil. In this case, the challenge for designers is getting longer lateral lines with high values of uniformity. The objective of this study was to develop a model to design longer lateral lines using non-pressure compensating drip hose. Using the developed model, the hypotheses to be evaluated were: a) the use of two different spacing between emitters in the same lateral line allows longer length; b) it is possible to get longer lateral lines using high values of pressure variation in the lateral lines since the distribution uniformity stays below allowable limits. A computer program was developed in Delphi based on the model developed and it is able to design lateral lines in level using non-pressure compensating drip hose. The input data are: desired distribution uniformity (DU); initial and final pressure in the lateral line; coefficients of relationship between emitter discharge and pressure head; hose internal diameter; pipe cross-sectional area with the dripper; and roughness coefficient for the Hazen-Williams equation. The program allows calculate the lateral line length with three possibilities: selecting two spacing between emitters and defining the exchange point; using two pre-established spacing between emitters and calculating the length of each section with different spacing; using one emitter spacing. Results showed that the use of two sections with different spacing between drippers in the lateral line didn't allow longer length but got better uniformity when compared with lateral line with one spacing between emitters. The adoption of two spacing increased the flow rate per meter in the final section which represented approximately 80% of the lateral line total length and this justifies their use. The software allowed DU above 90% with pressure head variation of 40% and the use of two spacing between emitters. The developed model/software showed to be accurate, easy to handle and useful for lateral line design using non-pressure compensating drip hose.

Diagnóstico socioambiental da bacia do Ribeirão Água-Fria, Município de Bofete - SP

Pós-graduação em Agronomia (Irrigação e Drenagem) - FCA

Caracterização do aço inoxidável ASTM A743 CA6NM e do seu revestimento de WC-10Co-4Cr aspergido termicamente por HVOF

Pós-graduação em Engenharia Mecânica - FEG

Análise morfométrica e definição do potencial de uso do solo da microbacia do rio Veríssimo, Veríssimo - MG

The morphometric study in watersheds is a key part to managing watersheds, because from the morphometric indices can determine the risks and potential of each watershed and assess environmental impacts on them generated mainly by human activities. This study aimed to characterize the watershed of the river Verissimo, located in the municipality of Verissimo - MG, analyze morphometric indices and propose how best to use the soil to minimize erosion impacts to resources hídricos.Foi used digital charts 1:100,000 scale and AutoCAD software for the quantification of vector data. The watershed has an area of 146.055 km2 , 55.902 km perimeter. According to the morphometric indices is considered 5th order, highly branched, slightly elongated format of little risk to floods occur, its main channel corresponds to 28.541 kilometers and has undulated, with an average slope of 8.59%. Through the results of morphometric indices and roughness coefficient, shows the potential of watershed land use on pastures for livestock, and soil conservation practices and water to minimize the impacts of erosion and contamination of water resources.

Increasing the lateral line length of drip irrigation systems

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Geoprocessamento de variáveis morfométricas para caracterização da microbacia do Córrego do Petiço

This study aims to perform the morphometric characterization of the watershed stream Petiço, Botucatu-SP, through techniques of GIS by GIS IDRISI Selva and Charter planialtimetric Botucatu (SF-22-ZB-VI-3) , edited by IBGE (1969), scale 1: 50000 for ranking the drainage network and the morphometric analysis. The variables analyzed were the dimensions, the relief pattern, pattern of the drainage network and the shape variables. The results show that related to how the watershed has an oblong shape with environmental interpretation with low tendency to flooding and erosion. The sinuosity index of 1.22 shows that the channels of the micro tend to be somewhat sinuous, which allows to infer that is permeable soil with good water infiltration. Based on the results of the morphometric variables was found that the watershed is in good condition of conservation, however, presents certain risks of susceptibility to erosion, and environmental degradation in some points, being fundamental to the maintenance of vegetation cover, in view of the roughness coefficient (Rn). Thus, the evaluation of morphometric characteristics in the study watershed constitutes an important tool in conjunction with the use of GIS and Geographic Information Systems makes possible the planning and management of natural resources aimed at their conservation.

Geoprocessamento aplicado na caracterização morfométrica da microbacia do Ribeirão Descalvado - Botucatu (SP)

The objective of this study was to evaluate geoprocessing to morphometrically characterize the Ribeirão Descalvado micro watershed – Botucatu, SP by the Geographic Information System (GIS) – Selva for preservation, rationalization of its use and environmental restoration. The micro watershed is 2,228.61 ha between the geographic coordinates: 22° 50' 05" to 22° 54' 26" latitude S and 48° 22' 29" to 48° 26' 36" longitude W Gr. The cartographic basis was the planialtimetric chart of Botucatu (SP), 1: 50000 scale (IBGE, 1969), used for extraction of level, hydrography and topography curves to determine morphometric indices. The results showed that low values of drainage density associated with the presence of permeable rocks facilitates ground water infiltration which decreases surface runoff, erosion risks and environmental degradation. The low value of the shape factor supported by the circularity index shows that the micro watershed is more elongated and at lower risk of more pronounced floods. The roughness coefficient environmental parameter classified the micro watershed for forest and reforestation.

Assoreamento de lago integrante da sub-baciado Córrego da Cascata, Botucatu, SP: implicações morfométricas

The watershed is considered a unit of territorial study, planning and land management, and is molded by the local geologic conditions and climate. Thus, this study aimed to assess the morphometric features of the subwatershed of Cascata Stream, in Botucatu (SP), and their implications for the siltation process in a lake. The assessment included indexes generated from data calculated by means of a digitalized cartographic basis georeferenced on the 1:10,000 scale using the software AutoCad map 2004. The software Quantum GIS 1.8 was also employed to generate the digital elevation model (DEM) and the map of declivities which led to the mean declivity (Dm) of the subwatershed. According to the indexes form factor (Kf), sinuosity (Is), circularity (Ic) and compacity coefficient (Kc), the subwatershed had elongated form, low propensity to floods and rapid flow. The draining density (Dd) and relief ratio (Rr) indicated more efficient mean drainage, favoring higher desiccation and mean erosive stage. The roughness coefficient (Cr) indicated that this subwatershed is suited to agriculture. The anthropic intervention at the watershed dividing line is the major factor for sediment carrying in the lake and compromises not only the landscape beauty, but also the aquatic life of this ecosystem.

Geomática aplicada na caracterização conservacionista de uma bacia hidrográfica no município de São Manuel (SP)

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Estudio experimental del desgaste del flanco y de la rugosidad superficial en el torneado en seco de alta velocidad del acero AISI 316L

La mejora continua de los procesos de fabricación es fundamental para alcanzar niveles óptimos de productividad, calidad y coste en la producción de componentes y productos. Para ello es necesario disponer de modelos que relacionen de forma precisa las variables que intervienen en el proceso de corte. Esta investigación tiene como objetivo determinar la influencia de la velocidad de corte y el avance en el desgaste del flanco de los insertos de carburos recubiertos GC1115 y GC2015 y en la rugosidad superficial de la pieza mecanizada de la pieza en el torneado de alta velocidad en seco del acero AISI 316L. Se utilizaron entre otros los métodos de observación científica, experimental, medición, inteligencia artificial y estadísticos. El inserto GC1115 consigue el mejor resultado de acuerdo al gráfico de medias y de las ecuaciones de regresión múltiple de desgaste del flanco para v= 350 m/min, mientras que para las restantes velocidades el inserto GC2015 consigue el mejor desempeño. El mejor comportamiento en cuanto a la rugosidad superficial de la pieza mecanizada se obtuvo con el inserto GC1115 en las velocidades de 350 m/min y 400 m/min, en la velocidad de 450 m/min el mejor resultado correspondió al inserto GC2015. Se analizaron dos criterios nuevos, el coeficiente de vida útil de la herramienta de corte en relación al volumen de metal cortado y el coeficiente de rugosidad superficial de la pieza mecanizada en relación al volumen de metal cortado. Fueron determinados los modelos de regresión múltiple que permitieron calcular el tiempo de mecanizado de los insertos sin que alcanzaran el límite del criterio de desgaste del flanco. Los modelos desarrollados fueron evaluados por sus capacidades de predicción con los valores medidos experimentalmente. ABSTRACT The continuous improvement of manufacturing processes is critical to achieving optimal levels of productivity, quality and cost in the production of components and products. This is necessary to have models that accurately relate the variables involved in the cutting process. This research aims to determine the influence of the cutting speed and feed on the flank wear of carbide inserts coated by GC1115 and GC2015 and the surface roughness of the workpiece for turning dry high speed steel AISI 316L. Among various scientific methods this study were used of observation, experiment, measurement, statistical and artificial intelligence. The GC1115 insert gets the best result according to the graph of means and multiple regression equations of flank wear for v = 350 m / min, while for the other speeds the GC2015 insert gets the best performance. Two approaches are discussed, the life ratio of the cutting tool relative to the cut volume and surface roughness coefficient in relation to the cut volume. Multiple regression models were determined to calculate the machining time of the inserts without reaching the limit of the criterion flank wear. The developed models were evaluated for their predictive capabilities with the experimentally measured values.