1 INTEGRATING 1D-2D HYDRODYNAMIC MODEL FOR SABARMATI UPPER RIVER BASIN WITH SPECIAL REFERENCE TO AHMEDABAD CITY AREA. Sejal Chandel ˡ, Dr. Suvarna Shah² ˡ PG Student, Department of Civil Engineering, Faculty of Technology and Engineering , The Maharaja Sayajirao University of Baroda, Vadodara, Gujarat, India ²Associate Professor, Department of Civil Engineering, Faculty of Technology and Engineering ,The Maharaja Sayajirao University of Baroda, Vadodara, Gujarat, India
[email protected] [email protected] Abstract In recent study, Gujarat has become one of the India’s most urbanized state, causing severe flash flooding. The Sabarmati river is one of the major west-flowing rivers in India and biggest river of north Gujarat. Urbanization should meet the population’s need by enlargement of paved areas, which has unusually changed the catchment’s hydrological and hydraulic characteristic. Therefore, the frequency of flash flooding in Sabarmati river has been increased. The Sabarmati river basin experienced eight times devastating flooding condition between 1972 to 2020.Among which July 2017 flooding event breakdown a 112 years old record of 1905. The Dharoi dam and Wasna barrage on Sabarmati river and surrounding district Kheda, Mehsana, Gandhinagar, Ahmedabad received a huge rainfall caused anomalous inflow to tributary which forced the dam authorities to release huge discharge in short duration. The Sabarmati riverfront of Ahmedabad had been going under water for five days due incessant rainfall in the city that leads to swelling of the Sabarmati River in 2017. In order to determine extent of Inundation, Hydrodynamic Model HEC-RAS(5.0.6) with Arc GIS was used. Various scenarios were run to study the impact of simulation on flood inundation(with & without riverfront project).The simulated flood depths have been compared with actual depths obtained at gauging station, which were collected from Government authorities.