Author(s): Liping Li; Minglong Dai; Wei Guo
Linked Author(s):
Keywords: WAT model; Probable maximum precipitation; Probable maximum flood; Himalayan region
Abstract: In order to estimate the probable maximum flood (PMF) for the design of hydropower station in ungauged basin, the daily hydrological model and reanalysis meteorological data are used to simulate the extreme flood. The Arun River is selected as the study area. Hershfield method is used to estimate the 3-day PMP using the mean, standard deviation and the frequency factor of the annual maximum rainfall series using the observed and Climate Forecast System Reanalysis (CFSR) data of 30 stations. The 3-day estimated weighted PMPs are divided according to the ratios of the maximum historical 3-day rainfall in recorded meteorological station. The Soil and Water Assessment Tool (SWAT) model is used to simulate the PMF by using the 3-day PMP. The Nash’s Efficiency and relative error are used to assess the calibration performance of the SWAT model. The results show that the Nash’s Efficiency (NE) estimated from the model is 78% with a relative error (RE) of 0.73 %, suggesting that the model is suitable for the simulation of PMF. The PMF values at the dam site is estimated to be 4990 m3/s. The simulated PMF is close to the 1 in 10000 year return flood (4870 m3/s) at dam site calculated by flood frequency analysis. The recommended PMF value at dam site is 4990 m3/s for security consideration. The proposed method provide a new approach to estimate PMF using the reanalysis meteorological data by hydrological model in ungauged basin.
Year: 2024