Extreme event characterization for the river basins of Eastern Indian Gangetic Plains

The Eastern Indian Gangetic Plains are characterized by a primarily nature-dependent region blessed with an enormous supply of mineral resources. The region is witnessing a rapid transition in its demographic structure because of rapid industrialization. The region provides a classic example of an area which shows a trend reverse to that observed globally, as far as the frequency of extreme precipitation events is concerned. This paper provides a risk characterization of the entire region, based on the empirical behavior shown by data available so far, in addition to predictions based on theory of extreme values. The long-term behavior prediction is made with an aim to provide policy makers ample time and direction to develop suitable disaster prevention measures. The focus is primarily on extremely high rainfall events, their frequency, trend and estimated long-term behavior. The study corroborates the stability assumption behind the Indian monsoon, and also provides an indication of the expected long-term as well as short-term threats. This study provides a unique application of the extreme value theory to help in developing a threat map for a region whose population is known to be highly impacted by any significant deviations from a normal monsoon.