One-Dimensional Study of Hydrodynamic Model Applied to a Channel Stretch of Stream of Gregório in São Carlos, Sp (PAP014816)

Código

PAP014816

Autores

Rodrigo Martins de Almeida, Luisa Fernanda Ribeiro Reis

Tema

Urban Floods

Resumo

This paper reports the committed effort to relate water level and flow, making use exclusively of level measurements in the field during the passage of waves through a crowded stretch of prismatic channel located on the city limits of São Carlos, called SP Stream Gregory. It had as main objective to make a study of one-dimensional hydrodynamic model and its application to a stretch of the channel. The first specific objective is to test and to elect for a systematic installation of a house to keep the level meters in the field and to monitor water levels during rainfall events for a stretch of river in the urban area of the city of São Carlos, SP. The second specific objective is based on building, testing and validating a computer program that implements the 1-D hydrodynamic flow model able to reproduce the hydraulic behavior during the passage of flood waves, using only data from water level, in order to estimate the corresponding flow. Different assemblies for data collection in the field were tested and the one-dimensional hydrodynamic model (1-D) for solving equations of Saint-Venant was used by the four points implicit method of Preissmann. Despite the potential of the method, as pointed out by some authors, this study reports difficulties in performing measurements on a stretch of urban channel and also problems in modeling stretch of canal in these very particular characteristics. Several analyzes were performed such as checking the number of time steps needed for minimizing the effects of the initial condition imposed (IQ1), verifying the celerity of the flood waves analyzing the peaks of events and so to be able to determine the Manning friction coefficient proposed by Arico et al. (2009) and the implicit method to solve the S-V equations proposed by Jin, Coran e Cook (2004), which behave as a filter based on the Froude number (condition-type flow), that was also tested. During the event of the day 23/03/2013, it was estimated speeds in the field. For each of the 12 recorded events, a simulation was made using a hydrodynamic model and the best result was used in a simulation to compare the second water depths observed and calculated. By analyzing how the values of maximum absolute errors (ERMAX1 and ERMAX2) represent for the highest recording obtained at the event, in percentage, there are events with 3.6% until absurd values from 27.1%. So, it is a theoretical-experimental that offers important information for future work in this direction.