پديد آورندگان :
اصغري سراسكانرود ، صياد نويسنده استاديار گروه جغرافيا، دانشگاه اروميه , , پيروزي، الناز نويسنده كارشناسي ارشد ژيومورفولوژي دانشگاه محقق اردبيلي , , زينالي، بتول نويسنده استاديار جغرافياي طبيعي دانشگاه محقق اردبيلي ,
چكيده لاتين :
Flood are main risks in mountainous areas. Aghlaghan chay watershed by having mountain face and the geological, lithologic and climate conditions is sustainable for the production of flood hazard.These phenomena every year causing damage in residential areas, road destruction and widespread creation and filling of reservoir sediment and riverbed sediment is Yamchi dam.
The Aghlaghan chay catchment area with 166 square kilometer area, bounded by late 38, 10-38,44N and long 47.46-48E. This catchment area is located in north western of Iran and south western slope of Sabalan Mountain. This study area in view of specifically regional situation such as topography (mountainous area), high slop, and existence of soft surface formation and non-resistant material which is located upper resistant layers and condition of climate has high potential of Flood hazard. Therefore, zonation of catchment area in view of sensibility to Flood is very necessary.
Methodology
In this research for gathering data and information, two methods of library and field study have been utilized. First of all, with study of resources, basic theory of research was investigated. Then according to study resources and field study with visual observation, effective factors in Flood were determined. In this research due to zoning of Flood hazard, we utilized from Vikor model and to obtain our purpose, 9 factors such as slope, aspect, lithology, elevation, rainfall, temperature, landuse, soil and distance from drainage were embedded. In the next stage, maps of effective factors in landslides of catchment area by geographical information system (GIS) were produced. Data set layers of access residential area, stream network, elevation classes, slope and aspect were derived from digitizing topography map of 1:50000 scale. Layer related litology were derived from digitizing of 1:100000 Meshkin geological maps. In order to obtain of land use layer, landuse map of Nir town used. In order to obtain, soil map of catchment area, soil of Ardabil Province and the soil map which produced by Sobhany via survey from Aghlaghan chay catchment area, were inserted. We exert climatology station data and gradient equation, for obtaining precipitation and temperature map. Finally, Vikor model as multiple decisions making according to zoning Flood hazard of Aghlaghan catchment area was applied. Vikor model in seven states has been done and this are described below:
First stage: configuration of decision matrix in respect of criteria number, Second stage: decision matrix normalization, in this stage we exert normalization as framework in fuzzy set (valuable range of 0-1), Third stages: determine of criterion vector weight, in this stage, according to exert weight, we used approach AHP, Forth stages: determine of best and worse variable for every criterion among existing of them, Fifth stages: compute amount of maximum suitable (S) and unsuitable (R), Sixth stages: compute index of Vikor (q), Seventh stages: ordering of criterion in according amount of .R, S, Q.
Results and discussion
In present investigate, we classify flood hazard in to five category include highest and lowest potential risk Very high class category is located the mountainous region of northern and southwestern basin. Most risk areas are located in the weathered volcanic formations, high percent slopes, slopes with low vegetation and overlooking the valley.In addition, mentioned regions are located away from stream network.
Conclusion
In this present research in according to classify of Aghlaghan chay catchment area Flood hazard, we exerted Vikor model which is one of multiple decision making analysis approach. According to the results, Slope, elevation and distance from drainage highest value allocated to flood in Aghlaghan chay watershed. Very high class category is located the mountainous region of northern and southwestern basin. All to over according to the study results, Aghlaghan chay basin have very high potential for the flood hazard event. Therefore, conservation measures, watershed and basin management studies are warrented.
