Integrated Modeling of the Lower Tapi Basin Using SWAT

Abstract

The Soil and Water Assessment Tool (SWAT) is a globally used integrated watershed model for studying sediment, hydrology, land use, climate change, in-stream water quality, and other water management actions on water quality and quantity. The present research aims to hydrological modeling of Lower Tapi basin using SWAT from Ukai dam to Surat city. Surat is one of India’s most densely populated cities, located at the tail portion of the Tapi River. One of the biggest flood occurred in the year of 1998 and 2006. The Soil and Water Assessment Tool (SWAT) was used to establish rainfall–runoff relationship for the Lower Tapi basin. The Lower Tapi basin runoff is estimated using the SWAT model, which combines GIS data with an attribute database. SWAT a physical-based semi-distributed parameter designed to predict runoff, effect of soil and anticipate the effect of land management approaches. SWAT model is developed for the base line scenario for 1998–2017. SWAT-cup is used to calibrate and validate the SWAT model. Then, using 19 years of daily precipitation as well as daily maximum and lowest temperature data, a SWAT simulation is run for each day to determine future runoff for the associated rainfall. On a daily time scale, the model was calibrated at the Mandvi gauging site. The observed flow data was used to identify sensitivity values, which were then calibrated. For auto-calibration and validation, the SWAT-CUP SUFI-2 software was employed. The calibrated model can be utilized for further in-depth study, such as water resource management and climate and land use change impact assessments.