'High intensity rain events will increase over Western Ghats'

CHENNAI: With the Northeast Monsoon intensifying in the state and the districts in Western Ghats region receiving heavy rainfall, a study conducted by the Ministry of Science and Technology warned that the frequency of extreme rainfall over Western Ghats river basins would increase in the near-future. An orange alert has been issued for those districts as Nilgris received 24cm of rainfall in a day.

In the past few decades, the increased frequency of hydroclimate extreme events over the Indian River basins (IRBs) due to global warming has led to a significant rise in flood-related disasters, mortality rates, and economic losses, ultimately affecting the gross domestic product, a conducted by scientists in Banaras Hindu University (BHU), said.

The study found that under low emission scenarios, the frequency of extreme rainfall is going to increase over the Western Ghat and northeast IRBs, while an increase in heavy rainfall intensity will be noticed in the upper Ganga and Indus basin. Also, approximately 4 per cent –10 per cent of the heavy rainfall is projected to increase over the western part of IRBs during the near-future (2021–2040) and mid-future (2041–2060).

"The projected frequency of consecutive wet days resulted in approximately 350–700 days over the Upper Ganga basin, inland drainage of Rajasthan, Cauvery, and East flowing river basin Mahanadi to Kanyakumari. And this depicts that the projected frequency of rainfall extremes has increased over the western Ghats, Indus River basin, and northeast river basins, including Brahmaputra and Barak and other river basins, " the study explained.

In the September, south-peninsular IRBs, the East-flowing Rivers (EFR) between Mahanadi and Kanyakumari have a projected mean precipitation from 4 to 9 mm per day.

This may lead to the urban flood over Hyderabad, Bengaluru, and Chennai - the cities situated under the peninsular IRBs. On the other hand, June-July months of the monsoon season will see heavy rainfall with high intensity over the western and central IRBs.

The results also showed that the significant changes in the frequency of hydro-climate extreme events may have a considerable impact on agriculture, health, and other socio-economic conditions of the society.

"The findings presented here are supporting basin-wise climate adaptation and mitigation strategies, including water and emergency services policies to minimize risk due to extremes in the basins, " the study said.