Wavelet analysis of rainfall and application of hydrological model in a semi-arid river basin of Rajasthan, India

Rainfall–runoff modeling requires a selection of a suitable hydrologic model for the determination of an accurate quantity. A better understanding of rainfall–runoff processes is important for stream flow generation within a river basin. This study investigate the long-term spatial–temporal trend of rainfall and streamflow using the hydrologic engineering center-hydrologic modeling system (HEC-HMS) model to understand the rainfall–runoff dynamics in the Banas River basin. Rainfall variability was analyzed for two periods: 1971–1995 and 1996–2020. Continuous wavelet transform was used to analyze the periodicity and the inter-seasonal relationship in rainfall. HEC-GeoHMS was used to generate the various inputs for the hydrologic modeling inputs for the HEC-HMS model. Initial constant loss and ModClark transform method were used to set up the HEC-HMS model for the study area. Calibration and validation of the model were performed using 3 years of observed data 2010–2012 and 2013–2015, respectively. Statistical model efficiency was checked using the coefficient of determination (R²), Nash–Sutcliffe efficiency, and root mean squared error to evaluate the performance of the HEC-HMS model. The finding indicated that the R² values are 0.80 for calibration and 0.82 for validation periods, respectively, which are in good arrangement with the measured values. This study analyzes the relationship between rainfall and runoff, which will aid in proper and efficient water resource management.