Impact of extreme events on the hydrological characteristics of Chilika Lake, east coast of India

Author(s): Pradipta Ranjan Muduli
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Institution or organization of origin: Chilika Development Authority, Wetland Research and Training Center
Country: India


Asia’s largest brackish water system Chilika Lake is situated at the shore of the Bay of Bengal (BoB) which has encountered a total of 1306 tropical cyclonic storms in the last 131 years. The present study was carried out to understand its impact, based on the available field data of more than two decades (1999 to 2020) and historical records from the literature. This study showed that both the ECE as well as a human intervention (opening of new mouth) had an integrated role in the maintenance of HC within the lake as indicated by the variability of salinity which is the lifeblood of the Chilika and controls the biodiversity. Major ECE factors which influenced the salinity regime in Chilika were freshwater input through cyclone-induced flash flood and seawater exchange through varying mouth conditions i.e., opening of the new mouth, shifting and widening of existing mouths due to cyclone impacts. As evidenced from the historical data available for ECEs, respective mouth variability, and salinity regime, ECE was found to maintain the salinity regime of the lake for a long run.

A robust statistical trend analysis i.e., auto-regressive integrated moving average (ARIMA) using 22 years of field data (n=7920) revealed that the salinity changes in the four sectors as well as overall Chilika remained unchanged since the last two decade. This study highlights the importance of historical data collection through a continuous lake monitoring program which would enable understanding the ecosystem functioning and behavior with ECE induced changing environmental conditions.

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