FLOOD FREQUENCY ANALYSIS USING GUMBEL EXTREME VALUE DISTRIBUTION METHOD: A CASE STUDY OF THE DIKRONG RIVER, NORTHEAST INDIA

DR. MADHURJYOJIT CHAKRAVARTTY

Volume : VII, Issue : XI, November - 2018

FLOOD FREQUENCY ANALYSIS USING GUMBEL EXTREME VALUE DISTRIBUTION METHOD: A CASE STUDY OF THE DIKRONG RIVER, NORTHEAST INDIA

Dr. Madhurjyojit Chakravartty

Abstract :

Flood frequency analysis has been carried out for the Dikrong river, an important tributary of the Subansiri river, the latter being a major tributary of the river Brahmaputra located in northeast India. The Dikrong river is subjected to severe flood during monsoon times. As such the frequency analysis has been conducted to relate the magnitude of events to their frequency of occurrence through probability distribution. Gumbel’s Extreme Value distribution has been tested and used for consideration for a 30 year discharge data from 1979 to 2008. From the values of discharge against the respective return periods, it has been determined that in a period of 400 years, discharges of 706.268m³/sec, 953.864m³/sec, 1117.795m³/sec, 1478.579m³/sec, 1631.103m³/sec, and 1783.069m³/sec will occur 200 times, 80 times, 40 times, 8 times, 4 times, and 2 times respectively. A discharge of 1934.761m³/sec will occur once in every 400 years.