Flood Simulation in an Urban Catchment of Navi Mumbai City with Detention Pond and Tidal Effects Using FEM, GIS, and Remote Sensing

Abstract

Urban flooding caused by heavy rainfall and high tides is a major problem in many coastal cities. For example, major cities in India have witnessed loss of life and property, disruption to transport and power, and incidences of epidemic during monsoon, most notable among them Mumbai in 2005, Surat in 2006, and Kolkata in 2007. Thus, an effective coastal urban flood simulation tool that can be used to identify flood vulnerability locations is needed. In this paper, the flood simulation of an urban catchment of Navi-Mumbai, India, is analyzed with the help of an in-house-developed simulation model that accounts for the tidal variation with the provision of a detention pond. The model uses FEM for flood simulation and geographic information systems (GISs) and remote sensing for database preparation. Overland flow and channel flow are simulated in one dimension by using the kinematic wave and diffusion wave approximations of St. Venant’s equations. The developed models have been verified with models from the literature and found to be satisfactory. The model has been used to simulate four rainfall events of the urban catchment. Out of four events, three were nonflooding and one was a severe flooding event. For the nonflooding events, measured data were available, and the model results were satisfactory. The model could simulate the flooding event showing the flooded stretch of the channel. By using the flooding event, the location and size of the possible detention pond are also simulated and their effects have been analyzed.