استخراج پتانسيل سيل خيزي حوضه سيمينه رود با كمك تصاوير ماهواره اي، شاخص رطوبت توپوگرافي و ويژگي هاي مورفولوژيكي

The Extraction of Flood Potential of Simineh River Basin Applying Satellite Images, Topographic Wetness Index and Morphological Features

شناﺳــﺎﯾﯽ ﻣﻨــﺎﻃﻖ ﺳــﯿﻞﮔﯿــﺮ از راﻫﮑﺎرﻫــﺎي اﺳﺎﺳــﯽ در ﺑﺮﻧﺎﻣــﻪ رﯾــﺰي ﮐــﺎﻫﺶ اﺛــﺮات ﺗﺨﺮﯾﺒــﯽ ﺳﯿﻞ اﺳـﺖ. در ﻧﻮﺷـﺘﺎر ﭘـﯿﺶ رو از ﺷـﺎﺧﺺ ﻫـﺎي ﺗﻮﭘـﻮﮔﺮاﻓﯽ و ﻣﻮرﻓﻮﻟـﻮژﯾﮑﯽ ﺑـﻪ ﻣﻨﻈـﻮر ﺑﺮرﺳـﯽ ﺳــﯿﻞزاﯾــﯽ اﺳــﺘﻔﺎده ﺷــﺪه اﺳــﺖ. ﺑــﻪ دﻟﯿــﻞ اﺛﺮﮔــﺬاري وﯾﮋﮔــﯽ ﻫــﺎي ﻫﯿــﺪروژﺋﻮﻣﻮرﻓﯿﮏ در ﺳﯿﻞ زاﯾﯽ، اﯾﻦ وﯾﮋﮔﯽﻫـﺎ ﺑـ ﺎ ﻧـﺮم اﻓﺰارﻫـﺎي آرك ﺟـﯽ .آي .اس. و ﺳﯿﺴـﺘﻢ ﻣـﺪل ﺳـﺎز ﺣﻮﺿـﮥ آﺑﺮﯾـﺰ ﺑﺎ ﮐﻤﮏ ﻻﯾﻪﻫـﺎي ﻣـﺪل رﻗـﻮﻣﯽ ارﺗﻔـﺎع و ﺗﻮﭘـﻮﮔﺮاﻓﯽ اﺳـﺘﺨﺮاج ﺷـﺪﻧﺪ. ﺑـﻪ دﻟﯿـﻞ ﻧﺒـﻮد اﻃّﻼﻋـﺎت ﻣﯿﺪاﻧﯽ دﻗﯿﻖ و ﺑـﻪ روز از رﻃﻮﺑـﺖ ﺳـﻄﺤﯽ ﺧـﺎك، ﻻﯾـﮥ ﭘﻮﺷـﺶ ﮔﯿـﺎﻫﯽ و آﻣـﺎر ﺛﺒﺘـﯽ ﺑـﺎرش، از اﻣﮑﺎﻧـﺎت ﺳـﻨﺠﺶ از دور اﻗـﺪام ﺑـﻪ اﺳـﺘﺨﺮاج رﻃﻮ ﺑــﺖ ﺧـﺎك و ﺑـﺎرش ﺷـﺪه اﺳـﺖ. ﺑـﺮاي ﮐﻨﺘــﺮل و ﻣﻘﺎﯾﺴـــﮥ اﻃّﻼﻋـــﺎت ﺑـــﻪدﺳـــﺖآﻣـــﺪه از ﺗﺼـــﺎوﯾﺮ ﻣـــﺎﻫﻮاره اي، ﺑـــﺎرش ﻣـــﻮر خ 12 آذر 1395 ﺑﻪ ﻋﻨﻮان ﻧﻤﻮﻧـﮥ ﺑـﺎرش ﺳـﯿﻼﺑﯽ اﻧﺘﺨـﺎب ﺷـﺪ. ﺑـﺎ ﺗﻮﺟ ـﻪ ﺑـﻪ اﻫﻤ ﯿـﺖ ﺷـﺎﺧﺺ رﻃﻮﺑـﺖ ﺗﻮﭘـﻮﮔﺮاﻓﯽ ﺑــﺮاي ﺗﻮﺻــﯿﻒ ﺷــﺮاﯾﻂ رﻃــﻮﺑﺘﯽ ﺧــﺎك و ﺗﺨﻤــﯿﻦ وﯾﮋﮔــﯽ ﻫــﺎي ﻓﯿﺰﯾﮑــﯽ و ﻫﯿــﺪروﻟﻮژي از اﯾــﻦ ﺷﺎﺧﺺ اﺳـﺘﻔﺎده ﺷـﺪه و ﻧﻘﺸـﮥ ﺧﺮوﺟـﯽ ﺑـﻪ ﺻـﻮرت ﻃﺒﻘـﻪ ﺑﻨـﺪي در ﻣﻨﻄﻘـﻪ ﺑﺮرﺳـﯽ ﺷـﺪ. ﺑـﺮاي ﻧﻤــﺎﯾﺶ ﻧــﻮاﺣﯽ ﻣﺴــﺘﻌﺪ ﺳــﯿﻼب از ﻣــﺪل ﺗﺮﮐﯿﺒــﯽ ﮐــﻪ در آن از ﻻﯾــﻪ ﻫــﺎي رﻃﻮﺑــﺖ ﺧــﺎك ﺳــﻄﺤﯽ )از ﻣــﺪل ذوزﻧﻘــﻪاي ﻓﯿﺰﯾﮑــﯽ از ﺗﺼــﺎوﯾﺮ ﻟﻨﺪﺳــﺖ 8 اﺳــﺘﺨﺮاج ﺷــﺪ(، ﭘﻮﺷــﺶ ﮔﯿــﺎﻫﯽ، ﺑــﺎرش و ﺷــﺎﺧﺺ رﻃﻮﺑــﺖ ﺗﻮﭘــﻮﮔﺮاﻓﯽ اﺳــﺘﻔﺎده ﺷــﺪه اﺳــﺖ. ﭘــﺲ از ﻫﻤﺴــﺎنﺳــﺎزي ﻧﻘﺸــﻪ ﻫــﺎ و وزن دﻫــﯽ، رويﻫــﻢﮔــﺬاري ﻻﯾــﻪﻫــﺎ در ﻣﺤــﯿﻂ ﺳﯿﺴــﺘﻢ اﻃّﻼﻋــﺎت ﺟﻐﺮاﻓﯿــﺎﯾﯽ اﻧﺠــﺎم و ﻧﻘﺸــﮥ ﭘﺘﺎﻧﺴــﯿﻞ ﺳــﯿﻞزاﯾــﯽ ﺣﻮﺿــﻪ اﺳــﺘﺨﺮاج ﺷــﺪ و ﺣﻮﺿــﻪ ﺑــﻪ ﺗﺮﺗﯿــﺐ ﺷــﺪ ت ﺳــﯿﻞزاﯾــﯽ ﺑــﻪ ﭘــﻨﺞ ﻣﺤــﺪودة ﻣﺴــﺘﻌﺪ ﺳــﯿﻼب، ﺳــﯿﻼب ﻣﺘﻮﺳ ــﻂ، ﺗﺎﺣــﺪودي ﺳــﯿﻼﺑﯽ، ﺳــﯿﻼب ﺑﺴــﯿﺎرﮐﻢ و ﻓﺎﻗــﺪ ﺳـﯿ ﻼب ﻃﺒﻘــﻪﺑﻨـﺪي ﺷــﺪ. ﺑﺮاﺳـﺎس ﻧﻘﺸــﮥ اﺳـﺘﺨﺮاﺟﯽ و ﺗﺠﺰﯾــﻪ و ﺗﺤﻠﯿـﻞ ﻧﺘــﺎﯾﺞ، از ﮐــﻞ 3279 ﮐﯿﻠــﻮﻣﺘﺮ ﻣﺮﺑــﻊ ﻣﻨﻄﻘــﻪ، ﺣــﺪود 81/6 ﮐﯿﻠــﻮﻣﺘﺮ ﻣﺮﺑــﻊ )2/5%( ﻣﺴــﺘﻌﺪ ﺳــﯿﻼب ﺑــﻮده و 1/9% از ﻣﻨﻄﻘـﻪ ﺑـﺎ ﻣﯿـﺰان ﺧﻄـﺮ ﻣﺘﻮﺳ ـﻂ ﺑـﺮاي ﺳـﯿﻼب ﺷﻨﺎﺳـﺎﯾﯽ ﺷـﺪ. ﻣﺤـﺪود ه ﻫـﺎي ﻣﺴـﺘﻌﺪ ﺳــﯿﻼب ﺑﯿﺸــﺘﺮ در ﻧــﻮاﺣﯽ دﺷــﺘﯽ ﻣﺮﮐــﺰي و ﺷــﻤﺎل ﺣﻮﺿــﻪ در زﻣــﯿﻦ ﻫــﺎي ﻣﺴــﻄّﺢ ﺣﺎﺷــﯿﻪ اي رود ﺳﯿﻤﯿﻨﻪ ﻗﺮار ﮔﺮﻓﺘﻪ اﺳﺖ.

Identifying flood-prone areas is one of the essential strategies in planning to mitigate the damaging effects of floods. In this study, topographic and morphological indices were used to investigate flooding. Due to the effect of hydrogeomorphic features on flooding, these features were extracted by ARCGIS software and watershed modeling system with the help of digital elevation model and topography layers. Due to lack of accurate field data and incidence of soil moisture, vegetation layer and precipitation statistics from remote sensing facilities, soil moisture and precipitation were extracted. In order to control and compare the information extracted from precipitation satellite images dated December 03, 2016, it was selected as a flood sample. Due to the importance of topographic moisture index to describe soil moisture conditions and estimation of physical and hydrological characteristics, this index was used and the output map was classified according to the area. To illustrate flood-prone areas, a hybrid model was used in which the soil surface moisture layers (optical trapezoidal model was extracted from Landsat 8 images), vegetation, precipitation and topographic moisture index were applied. After mapping the maps and weighting, the layers were merged into GIS environment and the flood potential map of the basin was extracted and the basin was flooded with five flood susceptibility ranges, moderate floods, partly floods and floods, respectively. The flood was classified. According to the extraction map and analysis, out of 3279 km2, about 81.6 km2 (2.5%) were susceptible to flood and 1.9% of the area with moderate risk of flood was identified. Most flood prone areas are located in the central plain and the north of the basin in the flat marginal lands of the Simineh River.