Impact Assessment of Urban Flood in Surat City using HEC-HMS and GIS

Abstract

Flood is natural disaster which is occurring in almost every part of the country. Total of 30 years (1985-2016) hydrological data has been given as an input to the model study. In order to run HEC-HMS model for assessment of flood at Surat outlet of Tapi river basin the input such as Rainfall, soil map and land use/land cover map required are extracted from soil. The hydrology of the area is characterised by high interaction between ground water and surface water. Input files were prepared using HEC-GeoHMS and later imported to HEC-HMS along with the meteorological and hydrological data to calculate run-off at the watershed outlet. Analysis was carried out in HEC-HMS to determine peak stream flow and occurrence time. SCS (Soil Conservation service) method can be used for flood stimulation in HEC-HMS. From the values of R2 (coefficient of determination) and from stimulated Qpeak (discharge) and observed Qpeak the flood model can be derived in HEC-HMS. Satellite image of area near Tapi region is selected and with the help of software we could analyse the flood prone areas. Parameters like population Density, resources availability, Elevation of geographical area, etc. database can be collected using GIS. Software like ArcGIS can be used to get the data of flood. From the data obtained using HEC-HMS and GIS the area of surat are divided into High risk and Low risk zones. Based on this study it will be helpful in identification of low lying & flood prone areas in Surat city and also helpful in Surat urban planning near Tapi River.

Keywords: River; HEC-HMS;HEC-GeoHMS; Rainfall; Runoff; Modelling

JEL Classification: O30