Author(s): T. I. Eldho; D. V. S. Nunna
Linked Author(s): Eldho T.I.
Keywords: Coastal hydrodynamics; Urban flooding; Tidal effects; Finite element method; Dynamic wave model; Geographic Information Systems
Abstract: The development of urban areas in the coastal region coupled with tidal effects generally aggravates the flood problem in heavy rainfall season. In developing countries like India, coastal urbanization is not always accomplished by the implementation of the adequate storm water facilities. Lack of planning frequently worsens this situation. Increased volume, higher and earlier peak runoff, increased imperviousness are some of the characteristics of urban watershed. These problems lead to the necessity of having a better insight into understanding the tidal effects on the flooding and storm water drainage for the coastal urban areas. Numerical methods such as Finite Difference Method (FDM) and Finite Element Method (FEM) are the main modeling tools for urban flood simulation. The development of geographic information systems (GIS) has significantly changed the way we acquire and use spatial data, and thus has introduced the potential for increasing the use of physical watershed characteristics in hydrologic modeling. So there is a need for combined use of these techniques. In this paper runoff model for coastal urban watershed considering the effects of tidal variations using FEM in one dimension is developed. Overland flow is modeled using mass balance equation considering the impervious character of urban watershed. Storm water flow through the channels is modeled using dynamic wave form of the Saint Venant’s equation and considering the tidal variations. Galerkin’s FEM is used in the approximation of governing equations. The developed model has been applied to the flooding analysis of a coastal urban watershed in Navi Mumbai, India to analyze the flooding in monsoon season with tidal influences. The model could satisfactorily predict the flooding due to heavy monsoon rains coupled with tidal variations. The developed model will be useful in urban coastal flood analysis due to tidal effects.
Year: 2010