Vol.:(0123456789) 1 3 Modeling Earth Systems and Environment https://doi.org/10.1007/s40808-020-00961-0 ORIGINAL ARTICLE Application of new HEC‑RAS version 5 for 1D hydrodynamic food modeling with special reference through geospatial techniques: a case of River Purna at Navsari, Gujarat, India Azazkhan I. Pathan 1  · P. G. Agnihotri 1 Received: 3 July 2020 / Accepted: 1 September 2020 © Springer Nature Switzerland AG 2020 Abstract Floods are among the extreme natural events which result in catastrophic damage to properties and adversely efects com- munities. To curb and manage the efects of such events, the decision-makers and disaster management authorities require dependable data in terms of food depth, discharge, magnitude, and special datasets. The low lying areas of Navsari city was inundated in the foods of 2002 and 2003. This study aims to use the latest version of HEC-RAS for 1D hydrodynamic food modelling of Purna river in Navasari city, Gujarat, India, with special reference to geospatial techniques. This study is aimed to demonstrate the geospatial analyzing capabilities of HEC-RAS v5. For the purpose of food modeling, the river data such as bank lines, fow path lines, cross-section cut lines are extracted from Cartosat-1 DEM (Digital Elevation Model). Steady fow analysis is carried out for the simulation of a 1D hydrodynamic model. The outcome obtained from the model is in the form of water depth, which can be observed in the geospatial HEC-RAS mapper window. The food depth maps for the 2002 and 2004 food events are generated, which indicate that the low lying areas of Navsari city near Jalalpore and Viraval are susceptible to fooding when the discharge in the river exceeds 8836 m 3 /s. The accuracy of the model is calculated by comparing the simulated data with the observed data for the above-mentioned food events. The results obtained from the 1D models are promising and accurate. Keywords Flood modeling · 1D hydrodynamic model · HEC-RAS · Geospatial techniques Introduction Floods are regarded as one of the major natural disasters the consequences of which exceeds other natural calamities and afects communities (Quirogaa et al. 2016). Flooding occurs when the discharge in the river increases to a point that the water overtops the banks and inundates the adja- cent areas, thereby afecting communities residing in the vicinities. Generally, a food is probably the world’s major, rehashing, catastrophic, and constant coverage (Samaras- inghe et al. 2010). Furthermore, climate change will likely increase the occurrence of foods and their magnitude. Flood risk assessment and management are important actions to identify existing threats, food-prone areas, and to mitigate potential food events (Ranzi et al. 2011). It is necessary to understand the food and to assess the results of the planned measures to devise a food management strategy. One simple method is to evaluate foods based on reconnaissance survey of in situ food levels (Hagen et al. 2011). Generally, data is not readily available for in situ food level observations. Flash foods are among the destructive natural disasters in India’s mountainous area. Diferent GIS and RS applications are convenient for extracting the river geometry data. Hydraulic and hydro- logic models like HEC-RAS, HEC-HMS were used to assess the food risk on the upper Tista river basin (Prakash Mandal and Chakrabarty 2016). Pluvial food has increas- ingly been acknowledged as a serious threat to many cities around the world. As far as pluvial food is concerned, 1D sewer, 1D, 2D overland fow, and coupling approach (1D-1D, or 1D-2D) would be an advanced approach to rec- ognize food modeling, food risk management, and food * Azazkhan I. Pathan pathanazaz02@gmail.com P. G. Agnihotri pga@ced.svnit.ac.in 1 Sardar Vallabhbhai National Institute of Technology, Ichchhanath, Surat 395007, India