Streamflow Estimation for Harangi River Basin, Karnataka, India

Abstract

Millions of people worldwide spend their entire day looking for water because it is so scarce. Therefore, conserving water is crucial, and it is believed that accurate estimation collection of runoffs is the first step to provide solutions to save water. This study used the Hydrologic Engineering Centre—Hydrologic Modelling System (HEC-HMS) model to simulate the Harangi River basin's reframed rainfall-runoff process (Area = 1703.0421 Km2) located in Kodagu District, Karnataka, India. The rainfall-runoff data were collected from 1995 to 2020 out of which five rainfall-runoff events were selected randomly for the study, three of these were designated for calibration, and the other two remained selected for validation. The Muskingum routing method was employed alongside the Soil Conservation Service—Curve Number (SCS CN) and the Soil Conservation Service Unit Hydrograph (SCS UH) to analyze and determine runoff characteristics. This included estimating runoff volume, peak runoff rate, and conducting flow routing assessments. The evaluation of the model's performance was conducted based on several criteria, including Nash Sutcliffe Efficiency (NSE), coefficient of determination (R2), and root mean square error (RMSE). The outcomes demonstrated that the model functions effectively during both the validation and calibration phases (NSE = 0.895, R2 = 0.948, RMSE = 346.435 m3/s; NSE = 0.887, R2 = 0.917, RMSE = 131.476 m3/s). Thus, the model can be used to manage different flood events and adopt effective decision and warning systems. Furthermore, other catchments with similar hydrological characteristics can use the created models. © The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd. 2025.