An Evaluation
of Probability of Occurrence of Hydrological Extremes
Joisy M.B. and Varghese Deepa G.S.
Disaster Advances; Vol. 14(8); 69-78;
doi: https://doi.org/10.25303/148da6921; (2021)
Abstract
The hydrological extremes viz. droughts and floods, are global recurring natural
hazards which are dynamic with respect to space and time impacting many people.
The increase in the number of instances of these hydrological events in the past
has steered the research in the direction towards evaluation of probability of occurrence
of droughts and floods on a catchment scale, for proper planning and decision making
in ideal allocation of the scarce water resources and mitigation of flood. Understanding
and evaluating hydrological extremes becomes important in terms of sizing of storage
reservoirs for combating droughts and floods, while its prediction becomes the key
in reduction of its consequences.
This study presents a summarized evaluation of probability of occurrence of floods
and droughts in Bhavani basin of Kerala, using Herbst method, for a period of 40
years from 2002 to 2042, using streamflow data. As per the analysis, the most severe
drought is expected to hit the basin in the year 2022- 2023 while the worst flood
is expected in the year 2040 -2041. The novelty of the study is in applying the
Herbst method for evaluating the probability of occurrence of floods in a catchment
area without adopting rigorous hydrological modelling techniques.
