Flood analysis of Bitlis Stream using by Geographical Information Systems (GIS)

Floods are one of the frequent natural disasters which threaten the settled areas. Specially, floods are bringing higher risks for increasing settled areas where depending on rises of population and rising industrial facilities for all that because of increasing interventions to the nature with effecting changing global climate daily. Therefore, one of the most important problems of civil engineering is the flood control studies. For an effective flood control, it is important to estimate the basin hydrology and flood conditions previously. In this study, it has been aimed to estimate the local hydraulic and hydrologic data of flood that passing from city center of Bitlis Stream. Bitlis city center has established around the river by the reason of security and water resources, and the city has an irregular urbanization for valley topography because of exposure, so care should be taken in terms of floods. The river reaches at high flow rate due to the underground spring water, periodical rains and instantaneous snowmelts, and it has been threatening to domicile and the city center. In the field of activity has included ArcGIS software from Geographic Information Systems and software of HEC-GeoRAS which is integrated with this software. First of all, it has obtained the basin's numerical gradient models with the help of ArcGIS by using 1/5000 scale base maps provided by local government. Then, water face profiles and hydrological characteristics of the flood base have been determined with aid of HEC-RAS (Hydrologic Engineering Centers-River Analysis System) software which is developed by US Army Corps of Engineers. As a final step of the analysis, obtained flood maps and water face profiles which are made up at the HEC-RAS are transferred to HEC-GeoRAS one more time. As a result, different flood scenarios that may occur in different periods were evaluated and solutions were discussed.