پهنه بندي خطر وقوع ناپايداري دامنه اي در حوضه آبريز بالقلو چاي اردبيل با استفاده از روش سلسله مراتبي فازي

Slope instability hazard zonation in Baleghluchai watershed in Ardabil using AHP Fuzzy method

زﻣﯿﻦ ﻟﻐﺰشﻫﺎ و ﻧﺎﭘﺎﯾﺪاريﻫﺎي داﻣﻨﻪ از ﺟﻤﻠﻪ ﻣﺨﺎﻃﺮات ﻃﺒﯿﻌﯽ ﻣﻬﻤﯽ ﻫﺴﺘﻨﺪ ﮐﻪ ﻫﻤﻪ ﺳﺎﻟﻪ ﻣﻮﺟﺐ ﺧﺴﺎرتﻫﺎي ﺟﺎﻧﯽ و ﻣﺎﻟﯽ و از دﺳﺖ رﻓﺘﻦ ﻣﻨﺎﺑﻊ اﻗﺘﺼﺎدي ﻣﯽﺷﻮﻧﺪ. اﯾﻦ ﻣﺨﺎﻃﺮات ﺑﯿﺸﺘﺮ در ﺷﯿﺐﻫﺎي ﻃﺒﯿﻌﯽ ﯾﺎ ﺗﻐﯿﯿﺮ ﯾﺎﻓﺘﻪ ﺑﻪ دﺳﺖ اﻧﺴﺎن اﺗﻔﺎق ﻣﯽاﻓﺘﺪ. ﭘﻬﻨﻪ ﺑﻨﺪي ﺧﻄﺮ وﻗﻮع زﻣﯿﻦ ﻟﻐﺰش از ﺟﻤﻠﻪ روشﻫﺎﯾﯽ اﺳﺖ ﮐﻪ ﺑﺎ اﺳﺘﻔﺎده از آن ﻣﯽﺗﻮان ﻣﻨﺎﻃﻘﯽ را ﮐﻪ در ﻣﻌﺮض ﺧﻄﺮ وﻗﻮع زﻣﯿﻦ ﻟﻐﺰش ﻫﺴﺘﻨﺪ ﺗﻌﯿﯿﻦ ﮐﺮد و ﺑﺎ اﺳﺘﻔﺎده از ﻧﻘﺸﻪﻫﺎي ﭘﻬﻨﻪ ﺑﻨﺪي ﺷﺪه ﺟﻬﺖ ﺗﻘﻠﯿﻞ ﺧﺴﺎرات ﻧﺎﺷﯽ از آن ﺑﺮﻧﺎﻣﻪ رﯾﺰي و ﻣﺪﯾﺮﯾﺖ اﻧﺠﺎم داد. در اﯾﻦ ﺗﺤﻘﯿﻖ ﺑﻪ ﺑﺮرﺳﯽ ﭘﻬﻨﻪ ﺑﻨﺪي ﺧﻄﺮ وﻗﻮع زﻣﯿﻦ ﻟﻐﺰش در ﺣﻮﺿﻪ آﺑﺮﯾﺰ ﺑﺎﻟﻘﻠﻮ ﭼﺎي ﭘﺮداﺧﺘﻪ ﺷﺪه اﺳﺖ. در اﯾﻦ ﺗﺤﻘﯿﻖ اﺑﺘﺪا ﻋﻮاﻣﻞ ﻣﻬﻢ ﻫﺸﺖ ﮔﺎﻧﻪ ﺷﯿﺐ، ﺟﻬﺖ ﺷﯿﺐ، زﻣﯿﻦ ﺷﻨﺎﺳﯽ، ﺧﺎك، اﻗﻠﯿﻢ، ﻓﺎﺻﻠﻪ از ﺟﺎده، ﻓﺎﺻﻠﻪ از رودﺧﺎﻧﻪ و ﮐﺎرﺑﺮي اراﺿﯽ ﺗﺸﺨﯿﺺ داده ﺷﺪﻧﺪ. ﻣﻮاد و روش ﻣﻮرد اﺳﺘﻔﺎده در اﯾﻦ ﺗﺤﻘﯿﻖ ﺳﻠﺴﻠﻪ ﻣﺮاﺗﺒﯽ ﻓﺎزي در ﻣﺤﯿﻂ GIS ﻣﯽﺑﺎﺷﺪ ﺑﻪ اﯾﻦ ﺻﻮرت ﮐﻪ ﭘﺲ از ﺗﻬﯿﻪ ﻻﯾﻪﻫﺎي اﻃﻼﻋﺎﺗﯽ ﺑﺎ اﺳﺘﻔﺎده از ﭘﺎراﻣﺘﺮﻫﺎي ﻓﻮق و وزن دﻫﯽ ﺑﻪ آنﻫﺎ در ﻣﺤﯿﻂ GIS ﻧﻘﺸﻪ ﭘﺘﺎﻧﺴﯿﻞ ﺧﻄﺮ ﺑﺎ روش ﺳﻠﺴﻠﻪ ﻣﺮاﺗﺒﯽ )AHP( ﺗﻬﯿﻪ ﺷﺪ و ﻃﺒﻘﻪ ﺑﻨﺪي ﺑﺎ روش ﻓﺎزي در ﻣﺤﯿﻂ GIS اﻧﺠﺎم ﺷﺪ. ﻧﺘﺎﯾﺞ ﺑﻪ دﺳﺖ آﻣﺪه ﻧﺸﺎن ﻣﯽدﻫﺪ ﮐﻪ ﺑﯿﺸﺘﺮﯾﻦ درﺻﺪ در ﺳﻄﺢ ﺣﻮﺿﻪ ﺑﻪ ﺗﺮﺗﯿﺐ ﻣﺮﺑﻮط ﺑﻪ ﭘﺘﺎﻧﺴﯿﻞ ﭘﺎﯾﯿﻦ )32,21%( و ﮐﻤﺘﺮﯾﻦ درﺻﺪ ﻣﺮﺑﻮط ﺑﻪ ﭘﺘﺎﻧﺴﯿﻞ ﺑﺴﯿﺎر ﺑﺎﻻ )13,5%( ﻣﯽﺑﺎﺷﺪ. ﻣﻨﺎﻃﻖ ﺑﺎ ﭘﺘﺎﻧﺴﯿﻞ ﺑﺴﯿﺎر ﺑﺎﻻ و ﺑﺎﻻ ﺑﺮاي وﻗﻮع زﻣﯿﻦ ﻟﻐﺰش ﺑﺎ ﻣﺴﺎﺣﺖ 327,39 ﮐﯿﻠﻮﻣﺘﺮ ﻣﺮﺑﻊ در ﺷﻤﺎل ﻏﺮب و ﻗﺴﻤﺖﻫﺎي ﮐﻮﭼﮑﯽ در ﺟﻨﻮب و ﺷﺮق ﺣﻮﺿﻪ واﻗﻊ ﺷﺪهاﻧﺪ و ﭘﺘﺎﻧﺴﯿﻞ ﺑﺴﯿﺎر ﭘﺎﯾﯿﻦ و ﭘﺎﯾﯿﻦ ﺑﺎ ﻣﺴﺎﺣﺖ 504,06 ﺑﯿﺸﺘﺮ ﻗﺴﻤﺖﻫﺎي ﻣﯿﺎﻧﯽ ﺗﺎ ﺷﻤﺎل ﺷﺮق و ﺟﻨﻮب ﺣﻮﺿﻪ را در ﺑﺮ ﻣﯽﮔﯿﺮﻧﺪ.

Landslides and slope instabilities are among the important natural hazards, which cause human and financial casualties and loss of economic resources every year. These hazards mostly occur in natural slopes or those manipulated by human. Landslide hazard zonation is one of the methods by which, areas prone to landslide occurrence can be determined and plannings can be done using the obtained zonation maps to reduce the casualties. The aim of this contribution is to study landslide hazard zonation within the Baleghluchai watershed in NW Iran. First, the main factors including the slope and its direction, geology, soil, climate, distance from the road and river and land usage were determined. The method of current investigation was Fuzzy AHP in the GIS environment, based on which, after preparing data layers using the above-mentioned parameters and giving weights to them in the GIS environment, the landslide potential map, as well as classification was carried out by Fuzzy AHP method. Results showed that the largest part of the watershed (32.21%) has low landslide potential, while about 13.5% of it has very high potential. Areas with very high and high landslide potential (327.39 km2 area) are mainly located in the northwest of the watershed, with some small areas distributed in the south and east, while areas with very low and low potential (504.06 km2) are mainly found in the central to northwestern and southern parts of the watershed.