Simulation and investigation into the pluvial effect on peri-urban unsewered drainage basin of Kolkata due to rapid urbanization

Abstract

A pluvial effect is a geologic event caused by the action of water during excessive precipitation in a particular region, resulting in water logging, which affects the drainage system of that area, or it may be caused by the spill of a large amount of water beyond the normal limit from the water bodies. The pluvial effect is also referred to as a flood having highly devastating consequences when it affects a region's urban or peri-urban areas. It affects the day-to-day activities of people staying in those areas and causes various social and economic losses. This effect would even grow further if proper planning and management of land were not done in a given time. Therefore, through this paper, the authors try to address the issue of urban flooding along with its consequences and impacts. For this study, the peri-urban region of the Tollygunge-Panchannagram Basin in Kolkata, India, is considered. The zero inertia model, Triangular Irregular Network Flood (TINFLOOD), is employed for surface flow simulation, whereas the storm water management model (SWMM) is used to determine the lateral flow. The output of this study provides various hyetographic presentations, considering infiltration during advanced, intermediate, and delayed rainfall conditions. Here, the time of concentration is also examined for different rainfall intensities to observe the time for peak flow. The simulated data obtained from this model has been validated with the real-time data of a pumping station situated at Chowbhaga. Nevertheless, this study helps assess flood risk management upstream of a region's basin and peri-urban areas.