Performance of urban storm drainage network under changing climate scenarios: Flood mitigation in Indian coastal city

Ramachandran Andimuthu,Palanivelu Kandasamy,B V Mudgal,Abinaya Balu,Guganesh Sankar,Anushiya Jeganathan

doi:10.1038/s41598-019-43859-3

Ramachandran Andimuthu, Palanivelu Kandasamy + Show 4 more

Open Access

https://doi.org/10.1038/s41598-019-43859-3

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Journal: Scientific Reports	Publication Date: May 23, 2019
Citations: 41	License type: open-access

Affiliation: Anna University, Chennai

Abstract

Managing storm water under climate uncertainty is a major concern in urban areas throughout the world. There were several floods events recorded in Chennai, a one of the major metropolitan coastal city in India. The flood incidences were repeatedly reported in recent decades. In this study, the existing state of storm water drains are evaluated under current and future climate scenarios in one of the most flood-prone areas of Chennai viz. Velachery zone. The mitigation measures are recommended to increase its resilience against floods. The Intergovernmental Panel on Climate Change (IPCC) CMIP5 models of Representative Concentration Pathways (RCP) 4.5 are used to develop possible future climate change scenarios of the city. The daily rainfall data for the period 1975–2015 obtained from India Meteorological Department are used to find the extremities and to generate Intensity-Duration-Frequency (IDF) curves. The IDF curves are generated for 2, 5, 10, 50, 100 year return period under current and future climate scenarios. The storm drainage network are delineated with Differential Geographic Positioning System (DGPS) survey. The integrated hydraulic and hydrological modelling is carried out to assess the flood carrying capacity of storm drainage under present and future climate scenarios. The vulnerable hotspots are identified and flood mitigation measures are suggested to reduce the flood risk at Velachery.

Highlights

54% of world’s population lives in urban areas and it is expected to increase up to 66% by 2050 and most of these urban areas are coastal cities
As per the Intergovernmental Panel on Climate Change (IPCC) Assessment Report 5, the number of heavy precipitation events has increased on land regions
During the flood in 2008 which was of moderate intensity, residential areas near Taramani link road got submerged in rain water

Summary

Introduction

54% of world’s population lives in urban areas and it is expected to increase up to 66% by 2050 and most of these urban areas are coastal cities. In the Asian region, strong variability is observed in precipitation trends and extremes in different parts and seasons of Asia[3] This changes in climate will disproportionately affect cities mostly located in climate-sensitive areas such as floodplains and coastal zones. The entire commercial, trading, transport (both land and air) and industrial activity stopped for several days These extreme events stress the need for flood assessment in Chennai under future climate change scenarios. Recent heavy flooding events in Chennai have prompted to have a relook into existing state of storm water drains stresses the need for flood management studies under present and future climate scenarios. The present study addresses the impacts of climate change on storm water management at Velachery – a flood-prone area of Chennai. The scientific knowledge of the study will help city planners to design intelligent climate-proof urban storm water drainage design

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