RIVER MODELING FOR FLOOD INUNDATION MAP PREDICTIONS USING 2D-HEC-RAS HYDRAULIC MODELING WITH INTEGRATION OF GIS

Abstract

Floods are natural disasters which if occurred produce damage to property and human life. The study of floods is important for protection of properties and human life risk. This study focuses on flooding characteristics in the flood plain of Tikurwha river catchment using two-dimensional (2D) hydrodynamic modeling. The flood inundation map of the flood prone areas is carried out using HEC-RAS 2D models with incorporation of Arc-GIS tools. Hence, using the magnitude of the flood at 2, 10, 50- and 100-year return period with a respective value of 72, 98.69, 123 and 135 (m3/s). The output of flood hazard inundation maps are carried out in 2D HEC-RAS Mapper in which the flood area at a respective return period’s flood magnitude are 75 ha, 102 ha, 108 ha, and 122 ha respectively. Based on the obtained flood inundation area, the economic impact of the flood at the specified return periods are estimated as 1791.99, 2436.89, 2589.45, and 2914.861 quintals of crop production were damaged due to flooding at respective return periods of 2, 10, 50 and 100 years.