Modeling of peak discharges and frequency analysis of floods on the Jhelum river, North Western Himalayas

The modeling of peak flood discharges and flood frequency analysis at various sites on a river is essential for planning, design, and management of hydraulic structures. The first and the foremost aim of this study is to choose the best-fit flood model among Log Pearson type 3 (LP3), Generalized Extreme Value (GEV), and Gumble (EV1) for each of the eight sites on the Jhelum River and for the same purpose goodness-of-fit tests like Anderson–Darling (A–D) and Kolmogorov–Smirnow (K–S) and distribution graphs (P–P plot and Probability difference graph) were used. The parameters of these models were determined by L-moments. The outcomes of the study reveal that the LP3 model is best-fit for Khanabal, Sangam, Awantipora, Padshahi Bagh, Ram Munshi Bagh, and Asham, and GEV is the best fit for Sopore, and Baramullah sites. Furthermore, peak discharges for 2-, 5-, 10-, 25-, 50-, 100-, 200-, and 500-year return periods were estimated and the analysis depicts that the discharge rate determined by distribution models at a return period of 5 years or more would surpass the safe carrying capacity (990.85 cumecs) of the Jhelum river. The study further shows that there exists a high positive correlation (R2 = 0.99) between observed and predicted peak discharges of LP3 and GEV models. Thus, indicating LP3 and GEV as best-fit models for modeling and flood frequency analysis of annual peak discharges on the Jhelum River.