“Inundation modeling using HEC- RAS software. Farka steam case study

Abstract

This study analysis how water flow corresponding to maximum discharge of Q=240m3 /s is distributed along Farka stream. To visualize flow dispersion, two modeling approaches 1-dimensional and 2- dimensional HEC-RAS models is implemented and unsteady flow analysis is simulated. HEC RAS models and hydraulic analysis are used to analyze water depth planimetry, flow hydrograph, water surface elevation and velocity against terrain of each stream segment. The first objective is to develop three 2-dimensional models, representing possible stream rehabilitation scenarios and to perform unsteady flow analysis in order to identify the most convenient case, for real application. Furthermore, the aim is to elaborate 1-dimensional model of the first scenario and to compare its results with the corresponding 2-dimensional model. In this study, it is concluded that all three 2-dmensional proposed cases, differ in terms of flow distribution along stream but, on the other hand, all of them are valid and efficient solutions for stream rehabilitation. Also, the generated results showed that flow distribution was not the same for 1 and 2-dimensional models. These two modeling approaches, under the same conditions, produces different results and only engineering experience together with project aim can decide which one of them to use.