Analysis of Regional Temporal Pattern of South-West Monsoon Rainfall… 125 Analysis of Regional Temporal Pattern of South-West Monsoon Rainfall over Mumbai as a Flood-Inducer Sherly M A 1 , Subhankar Karmakar 2,3 , Terence Chan 4 and Christian Rau 5 1 IITB-Monash Research Academy, Indian Institute of Technology Bombay Campus, Powai, Mumbai–400076, India 2 Centre for Environmental Science and Engineering, Indian Institute of Technology Bombay, Mumbai–400076, India 3 Interdisciplinary Program in Climate Studies, Indian Institute of Technology Bombay, Mumbai–400076, India 4 Monash Sustainability Institute and Water Studies Centre, Monash University, Australia 5 Department of Mathematics, Shantou University, P.R. China E-mail: 1 sherlyma@iitb.ac.in; 3 skarmakar@iitb.ac.in; 4 terence.chan@monash.edu; 5 rau@stu.edu.cn. ABSTRACT: The rainfall temporal pattern significantly affects flood peaks and volumes, and climate change due to natural and anthropogenic causes has altered the rainfall pattern leading to more frequent higher intensity rainfall events than in the past. This study investigates the changes in the regional temporal pattern of south-west monsoon rainfall and its influence on ever increasing flood events in Mumbai. The city, situated on the south-west monsoon belt of India, suffers from severe floods almost annually. The most devastating urban flood event of India occurred in Mumbai on 26 July, 2005 with the historic highest rainfall of 944 mm in 24 hours. This analysis based on hourly rainfall data during 1970–2010 collected from Colaba and Santacruz raingauge stations installed by India Meteorological Department (IMD), indicates the influence of climate change and urbanization on rainfall pattern, and the need for a modified urban design drainage method to combat floods. Keywords: Climate Change, Rainfall Temporal Pattern, South-West Monsoon, Urbanization, Urban Floods. INTRODUCTION According to Census of India 2011, Mumbai is the most populous city among all metropolitan cities in India, with an average population density of 20,000 per km 2 . The city, situated on the south-west monsoon belt of India receives an average annual rainfall of around 2400 mm and about 70% of this rainfall occurs just in two months, July and August, resulting in severe floods almost annually. The most devastating urban flood event of India occurred in the city on 26 July, 2005 with the highest ever recorded rainfall of 944 mm in 24 hours, claiming around International Symposium on Integrated Water Resources Management (IWRM–2014) February 19–21, 2014, CWRDM, Kozhikode, Kerala, India