No abstract

Devido à ausência de sistemas de drenagem eficientes e aos altos índices pluviométricos em determinados períodos do ano, eventos de inundação no mundo e no Brasil, e, principalmente, em Belo Horizonte-MG,  têm sido observados com muita frequência. À vista disso, este trabalho teve como objetivo desenvolver a modelagem hidráulica de um canal em meio urbano visando a discussão sobre a sua capacidade de drenagem e minimização de incertezas, relacionadas ao escoamento de água no canal em eventos extremos. Para a elaboração dos mapas e delineamento do canal foi utilizado o software ArcGIS, com suas extensões ArcHydro e HEC-GeoRAS. Além disso, para aplicação dos dados geométricos e hidráulicos das seções, e simulações hidráulicas, foi empregado o software HEC-RAS. Como resultado do estudo, teve-se a comprovação, quantitativa, da influência do coeficiente de Manning no escoamento do canal e pôde-se também, determinar, por meio de um conjunto de vazões críticas, trechos do curso d’água mais susceptíveis à inundação.  Observou-se que, quanto menores os valores dos coeficientes de Manning das seções, maiores são suas vazões críticas, ou seja, para corpos hídricos canalizados por obras com revestimento e com acabamento, as vazões necessárias para as seções inundar possuem valores mais altos, justamente, pelo menor atrito do material de revestimento com o fluxo de água; enquanto que, para canais naturais, as vazões determinantes para a ocorrência de inundação da seção, são menores, pela maior potencialidade da vegetação e do solo em resistir ao escoamento. Flooding Area Simulation through Hydraulic Modeling in the Urban Channel: Case Study Jatobá Stream, in Belo Horizonte, Minas GeraisA B S T R A C TDue to the absence of efficient drainage systems and high rainfall rates at certain times of the year, flood events in the world and in Brazil, and especially in Belo Horizonte, Minas Gerais, have been observed very frequently. In view of this, this work aimed to develop the hydraulic modeling of an urban canal in order to discuss its drainage capacity and minimize uncertainties related to water runoff in extreme events.For the maps elaboration and the channel drawing was used the ArcGIS software with its extensions ArcHydro and HEC-GeoRAS. The HEC-RAS software was used to apply the geometric and hydraulic sections data and for hydraulic simulations. As a result of the study, the influence of the Manning coefficient on the flow of a channel was quantitatively verified. Through a set of critical flows, it was also possible to determine the most susceptible to flooding watercourse stretches. In this case, it was observed that the smaller the values of the Manning coefficients of the sections, the higher their critical flow rates, that is, for water bodies piped by coated and finished works, the flow rates needed to flood the sections have higher values high due to the lower friction of the coating material with water flow; whereas, for natural channels, the water volumes per unit of time, which are determinant for the sections flooding, were smallers, precisely because of the greater capacity of the vegetation and soil to resist runoff.Keywords: hidraulic modelling, HEC-RAS, urban floods.

No abstract

The expansion of water distribution networks is nowadays essential to meet the pressing population growth in many cities worldwide. With the subsequent increase in water demand, the hydraulic behaviour of a water supply system can change dramatically due to the significant head losses in the pipes caused by the larger flows released by pumping systems and reservoirs to supply the higher water consumption of the network. Strategical studies are necessary to delimit risk regions where a demand increase may affect the system too negatively. To analyse expansion scenarios with the lowest risk of failure and damage for the supply network operations, this research studies hydraulic performance and connectivity under various demand increase scenarios using calculations of complex network metrics together with relevant hydraulic criteria. For these two types of calculations, this research, developed in a Python framework, uses, respectively, the NetworkX 2.5 and WNTR 0.3.0 packages. The C-Town network is employed as a case study, and demand increasing scenarios are implemented on 30 nodes along the peripheral regions of the network to simulate the growth of the cities. Then, these scenarios are evaluated using the TOPSIS methodology, thus determining the best and worst sectors to expand the capacity of the network.