FLOOD FREQUENCY ANALYSIS USING GUMBEL’S DISTRIBUTION METHOD: A LOWER DOWNSTREAM OF LOHIT RIVER (DANGORI RIVER), ASSAM (INDIA)

Flood frequency is the most important statistical techniques in understanding the nature of the flood and magnitude of the high discharge in a river. So, the flood frequency analysis is carried out of the Dangori River which is a part of the Downstream of Lohit River using Gumbel's distribution method which is one of the probability distribution methods used to model stream flows. The maximum discharge data of Lower Lohit river, from 1998-2018 (21 years flood data) were collected from the flood observatory. colorado website and considered for the flood frequency analysis using the Gumbel's distribution. From the trend line equation it shows that the R2 value which is 0.9204 and the pattern scatter is narrow and suitable for predicting expected flow in the river. The estimated flood discharge for coming 11.11 years is 57998.22 m 3 /sec and 22.22 years is 65215.61 m 3 /sec. The mean instantaneous flow is 40111.66 m 3 /sec and it is around the the return period of 2.2 years. This shows that the predictions of flood in the basin is nearly accurate and can be utilise in designing of importance hydraulic structure, planning purposes, bridges in the river reaches and conservation of Dibru Saikhowa National Park