The impact of short-duration precipitation events over the historic Cauvery basin: a study on altered water resource patterns and associated threats

Abstract

The Cauvery Delta, the ‘Rice Bowl’ of India follows a time-tested cultivation pattern over several irrigation zones. However, in this era of the Anthropocene, it is now well-established that short-duration, intense precipitation episodes will batter the flood plains year after year. The purpose of this first study is thus to quantify the impacts that such episodes may have on the floodplains of the Cauvery Delta and the concomitant threats to the historic Kallanai Dam. Precipitation events during the North-East monsoon period are driven not just by warm rain microphysics but also by large frozen hydrometeors falling from deep clouds causing undesirable flooding over the region to the extent of 66%. Additionally, from an assessment of the velocity heads and the floodwater depths, this study projects a heightened vulnerability. The total extent of submergence along riverbanks and other flow paths was estimated to be 145.98 $${\mathrm{km}}^{2}$$ km 2 out of which 65.14% of the submerged area is agricultural land. The most important conceptual advance established in this paper is that sub-zones in major watersheds that are currently safe will get inundated in the RCP8.5 warming scenario in 2050.

Turbulence-induced droplet grouping and augmented rain formation in cumulus clouds

“…Global warming-mediated weather extremes is likely to become the new norm in the coming decades. Shortduration extreme precipitation events cause local flooding at catastrophic levels requiring the evacuation of hundreds of thousands of people, whilst devastating droughts impact livelihoods and food production at the other extreme 79 . These disturbing trends are linked to the distribution of water resources across continents.…”