چکیده:
Many people's lives and property are threatened by annually around the world. Thus, it
is necessary to identify areas with flood risk in order to apply systematic management
in urban auriferous zones. First, topographic maps and Si valley Shirvan River
aquiferous land use was prepared and river basin border was drawn based on these
maps, then the river divided to 3 sub-basins and these sub-basins divided to 5
hydrological unit and these units divided to 4 sub- hydrological units, and flood
hydrographs were calculated in return periods of 2, 5, 10, 25, 50, 100, respectively.
Within the area of S1-1-1 with a length of 3.5 km in Si valley Shirvan River, geometric
information of river was obtained. In the next stage, by introduction of flow
characteristics and river geometric information and each profile coefficient in
HEC_RAS software, water level profile in different return periods was calculated and
average level and depth of flood for risk areas was determined. Finally, using flood
damages functions, damages were calculated and level-damage curve was drawn. The
results showed that damage increase trend of floods with a return period of more than
25 years and average flooding depth greater than 0.52 m is more intense.
خلاصه ماشینی:
Flood risk assessment in Ardabil valley Shirvan aquiferous zone Tahereh Zamani MA in Watershed Management, Islamic Azad University of Torbat-e Jam Original Article: Received 03 March.
First, topographic maps and Si valley Shirvan River aquiferous land use was prepared and river basin border was drawn based on these maps, then the river divided to 3 sub-basins and these sub-basins divided to 5 hydrological unit and these units divided to 4 sub- hydrological units, and flood hydrographs were calculated in return periods of 2, 5, 10, 25, 50, 100, respectively.
In the next stage, by introduction of flow characteristics and river geometric information and each profile coefficient in HEC_RAS software, water level profile in different return periods was calculated and average level and depth of flood for risk areas was determined.
It is necessary to transfer hydraulic calculation results in natural conditions to GIS and finally , results of mathematical model HEC-RAS for natural conditions in discharge mode with considered return periods (2,5,10, 25, 50 and 100 years) is located on modified topography (which is actually natural topography of the river) and riverbed is determined.
Accordingly, all cells that form ground level and water level are compared for floods with considered return periods and flooding zone is determined in studied area.
The relationship between flooding average depth (m) and flood damages Presentation and evaluation of results According to studied area and obtained results, following points can be cited: 1- With minimum cost, mapping information and required data and using combined application hydraulic software and GIS, we can determine flood zoning and rivers bed easily.