Integrated Modeling Approach to Simulate Hydrologic Process in Urban Watersheds (PAP014345)

Código

PAP014345

Autores

Aline Maria Meiguins de Lima, Edson Jose Paulino de Rocha, Everaldo Barreiros de Souza, Carla Cristina de Azevedo Sadeck, Maissa Ludymilla Carvalho Pontes, Wendy Kaori Matsunaga

Tema

Urban Floods

Resumo

Correct prediction of flood extents in urban catchments has become a risk issue especially in Amazon region where is located a vast drainage system associated to intense rainfall. The traditional approach focused in arranging channels, with the objective to minimize the flood effect can be in an initial moment, the better solution able to deal with floods in a certain area, without major consequences. However, the urban growing especially in expansion zones implies in significant stresses on the watersheds. Therefore, the better response is to try understanding how urbanization interferes in the flow patterns and the urban water environmental support capacity. The main purpose in this paper is simulate a set of physical attributes in watersheds with limited self-adjusting capacity in urban expansion areas associated to the process of urban growing in Metropolitan Region of Belém (RMB, Pará-Brazil). The study area, with about 123 km², is a zone of the economic and urbanization development, situated between the Guamá River and Guajará Bay, making part of the Amazon River estuary. The lowlands wet are the typical environment where occurs two major process: urban pluvial flooding, as a result of run-off accumulation and fluvial flooding as result of overflowing of river banks. In this work were employed the conceptual model (mathematical) and based on the attributes of the physical environment. In the characterization of the rainfall (13 years) were used: average monthly, cumulative annual, return time and probability distribution based on the methods of Ven Te Chow, Log-Normal, Log Pearson Type III and Gumbel, and in the simulation of the values of discharge was adopted the method of SCS (Soil Conservation Service). In the physical characterization of the watersheds was employed: geological units, terrain units, altimetry (digital elevation model) and morphometric elements. Were used several method for linear, areal and relief aspects studies, such as, Stream Order, Slope, Drainage Texture, Drainage Density, Hydrographic Density, Topographic Texture, Maintenance Coefficient, Channel Gradient, Infiltration Number and Bifurcation Ratio. In the analyzed period, the wettest years were: 2006 (3664 mm) and 2011 (3592 mm). The return time for 05 years considering the methods of Pearson Log-type III (3542 mm), Log-Normal (3537 mm), Ven Te Chow (3533 mm) and Gumbel (3497 mm) imply in a high probability of recurrence of periods of flooding. The SCS method (Soil Conservation Service) indicated the largest flows are expected in Una basin (3.81 m³/s), Black Water Lake basin (1.79 m³/s) and Val-de-Cans basin (1.15 m³/s). The simulation model was capable to incorporate all the drainage elements and their interactions properly, for an accurate prediction of urban flooding. The continued monitoring of rainfall in association with the physical parameters controlling the processes that occur in watersheds can provide a more effective flood prediction, useful in the urban flood disaster prevention system.