ABSTRACT
Globally unprecedented incessant rains have prompted dam authorities to frantically spill water to avert dam overflows and breaches. On many instances including the recent deluge in Kerala, India and Myanmar, the distress discharge without advanced communication, has added to flood miseries of the people, their livelihood and properties. As earth’s climate is changing rapidly and is affecting the magnitude and frequency of precipitations, the probability of flooding is expected to increase. The major risks when the dam is filled to the brim during the course of rainy season is the sudden upsurge in inflow (Hazard) from upstream dams and catchment areas. Risk mitigation is achieved only by release of large volume of water through all possible outlets. Since the lead time for flood mitigation is very limited, the most probable consequence is dam overflow, dam breaches, and inundation of lower plains (Vulnerability). In order to reduce effect of dam induced floods, a mathematical model is evolved, and a case study of Idukki dam in Kerala is done to re-estimate the flood control storage and to emphasize the need for an optimum spill and to start the spill in timely coordinated manner to avert flood disasters
