Projected Rainfall Intensity Duration Frequency Relationships under Climate Change: A Case Study of Thane City

Abstract

Climate change is the most important factor to increase in short-duration high-intensity rainfall and consequent flooding. Intensity-Duration Frequency (IDF) curves are commonly used tools in Stormwater design, so a method to derive future IDF curves including climate change effects could be necessary for mainstreaming climate change information into storm water planning. The objective of the present study is to define a mechanism to reflect the effect of climate change on the projected rainfall IDF relationships. For this, the continuously observed hourly rainfall data from 1969 to 2018 were divided into five subgroups. Then the IDF curve of each subgroup is defined. The rainfall intensity for the next 30 years was then estimated using a linear regression model. The obtained result indicates that for the same duration and for the same return period, the rainfall intensity is likely to increase over time: 17% (2019-2028), 25% (2029-2038) and 32% (2039-2048). However, the findings presented in this paper will be useful for local authorities and decision makers in terms of improving stormwater design and future flood damage will be avoided.