Analysis of Flood Peak Discharge Based on Watershed Shape Factors

Abstract

Regression analysis can develop unit hydrograph modeling by approaching the peak discharge (Qp) and time to peak (Tp) parameters. The main aim of this study is to design a model of peak discharge based on watershed shape factors. The watersheds used in this study are Bontojai Watershed, Jonggoa Watershed, Kampili Watershed, Maccini Sombala Watershed, and Jenelata Watershed, which have slopes criteria below 10% and have complete recorded data of Automatic Water Level Recorder (AWLR) and Automatic Rainfall Recorder (ARR). The validation results of corrected peak discharge data produce Root Mean Squared Error (RMSE). Then, the peak discharge model was conducted by regression analysis and validated with observed unit hydrographs. The results of this study indicate that the coefficient of determination R2 is 0.963. It means that the independent variable (x), namely the area of the watershed, the length of the main river, and the shape factor of the watershed, influences the peak discharge (Qp) of 96.3%