ارزيابي آسيب پذيري محيط زيستي آب هاي زيرزميني دشت بهار همدان به روش هاي تلفيقيAVI و GODS ،DRASTIC

Evaluating the environmental vulnerability of the groundwater of Hamedan’s Dasht-e Bahar through DRASTIC, GODS and AVI integrated methods

ﺳﺎﺑﻘﻪ و ﻫﺪف: اﯾﻦ ﭘﮋوﻫﺶ ﺑﺎ ﻫﺪف ارزﯾﺎﺑﯽ آﺳﯿﺐ ﭘﺬﯾﺮي آب ﻫﺎي زﯾﺮزﻣﯿﻨﯽ دﺷﺖ ﺑﻬﺎر ﻫﻤﺪان و ﻣﻘﺎﯾﺴﻪ ﭘﻬﻨﻪ ﺑﻨﺪي ﻫﺎ ﺑﺎ اﺳﺘﻔﺎده از روش ﻫﺎي GODS ،DRASTIC و AVI اﻧﺠﺎم ﺷﺪه اﺳﺖ. ﻣﻮاد و روش ﻫﺎ: ﭘﺲ از ﺷﻨﺎﺳﺎﯾﯽ ﻣﺤﯿﻂ زﯾﺴﺖ ﻣﻨﻄﻘﻪ و ﺟﻤﻊ آوري اﻃﻼﻋﺎت 70 ﺣﻠﻘﻪ ﭼﺎه در ﻣﺤﺪوه ﻣﻮرد ﻣﻄﺎﻟﻌﻪ، اﻃﻼﻋﺎت در ﻧﺮم اﻓﺰار GIS ﺑﻪ ﻻﯾﻪ ﻫﺎي رﺳﺘﺮي ﺗﺒﺪﯾﻞ ﮔﺮدﯾﺪ. ﭘﺲ از ﺗﻬﯿﻪ ﻻﯾﻪ رﺳﺘﺮي ﺣﺎﺻﻞ از ﻣﻮﻗﻌﯿﺖ ﭼﺎه ﻫﺎ و اﻃﻼﻋﺎت ﻣﻮرد ﻧﯿﺎز ﺑﺮاي ﺳﻪ روش، وزن دﻫﯽ رﺗﺒﻪ دﻫﯽ و ﮐﻼس ﺑﻨﺪي ﻫﺮ روش ﺻﻮرت ﮔﺮﻓﺘﻪ و ﻧﻘﺸﻪ ﻫﺎي آﺳﯿﺐ ﭘﺬﯾﺮي ﺳﻪ روش ﺑﺎ ﻫﻢ ﻣﻘﺎﯾﺴﻪ ﮔﺮدﯾﺪ. ﯾﺎﻓﺘﻪ ﻫﺎ: ﻧﺘﺎﯾﺞ ﺣﺎﺻﻞ از روش DRASTIC ﮐﻪ ﺗﻘﺮﯾﺒﺎً ﮐﺎﻣﻞ ﺗﺮﯾﻦ ﺷﺎﺧﺺ ﺑﺮاي ارزﯾﺎﺑﯽ ﭘﺘﺎﻧﺴﯿﻞ آﺳﯿﺐ ﭘﺬﯾﺮي آب ﻫﺎي زﯾﺮزﻣﯿﻨﯽ اﺳﺖ، ﻣﺤﺪوده آﺳﯿﺐ ﭘﺬﯾﺮي ﮐﻢ را 41/97 درﺻﺪ و آﺳﯿﺐ ﭘﺬﯾﺮي ﻣﺘﻮﺳﻂ را 57/68 درﺻﺪ، ﺑﺮآورد ﮐﺮده اﺳﺖ. ﻧﺘﺎﯾﺞ روش GODS، ﺑﯿﺎﻧﮕﺮ آن اﺳﺖ ﮐﻪ دﺷﺖ ﻣﻮرد ﻣﻄﺎﻟﻌﻪ در دو ﮐﻼس آﺳﯿﺐ ﭘﺬﯾﺮي ﮐﻢ و ﻣﺘﻮﺳﻂ ﺑﻪ ﺗﺮﺗﯿﺐ ﺑﺎ 81/50 و 18/50 درﺻﺪ ﻗﺮار دارد. ﻧﺘﺎﯾﺞ روش AVI ﻧﯿﺰ ﻧﺸﺎن ﻣﯽ دﻫﺪ ﮐﻪ 53/42 درﺻﺪ از آﺑﺨﻮان داراي ﭘﺘﺎﻧﺴﯿﻞ آﻟﻮدﮔﯽ ﮐﻢ و 46/58 درﺻﺪ از آن داراي ﭘﺘﺎﻧﺴﯿﻞ آﻟﻮدﮔﯽ ﻣﺘﻮﺳﻂ اﺳﺖ. در ﻫﺮ ﺳﻪ روش آﺳﯿﺐ ﭘﺬﯾﺮي، دﺷﺖ ﺑﻬﺎر در دو ﮔﺮوه آﺳﯿﺐ ﭘﺬﯾﺮي ﮐﻢ و ﻣﺘﻮﺳﻂ ﻗﺮار ﮔﺮﻓﺘﻪ اﺳﺖ وﻟﯽ ﺣﺪود ﮔﺴﺘﺮش ﻣﺤﺪوده ﻫﺎي آﺳﯿﺐ ﭘﺬﯾﺮي ﻣﺘﻔﺎوت ﻣﯽ ﺑﺎﺷﺪ. در دو روش دراﺳﺘﯿﮏ و GODS ﻣﺤﻞ ﻫﺎي آﺳﯿﺐ ﭘﺬﯾﺮي، ﺑﯿﺶ ﺗﺮ ﺑﺎ ﻫﻢ ﻫﻢ ﺧﻮاﻧﯽ داﺷﺘﻪ و روش دراﺳﺘﯿﮏ آﺳﯿﺐ ﭘﺬﯾﺮي آب ﻫﺎي زﯾﺮزﻣﯿﻨﯽ دﺷﺖ ﺑﻬﺎر را ﺑﯿﺶ ﺗﺮ از روش GODS ﺑﺮآورد ﮐﺮده اﺳﺖ. در دو روش دراﺳﺘﯿﮏ و AVI، ﭘﺮاﮐﻨﺪﮔﯽ ﭘﻬﻨﻪ ﻫﺎي آﺳﯿﺐ ﭘﺬﯾﺮي ﻣﺘﻮﺳﻂ ﻣﻮﺟﻮد ﻣﻨﻄﻘﻪ ﺑﺎ ﻫﻢ ﻫﻢ ﺧﻮاﻧﯽ دارد. ﻧﺘﯿﺠﻪ ﮔﯿﺮي: ﺑﻪ ﻃﻮر ﮐﻠﯽ ﻧﺘﺎﯾﺞ ﻧﺸﺎن دﻫﻨﺪه اﻧﻄﺒﺎق ﺑﯿﺶ ﺗﺮ ﻣﺪل ﻫﺎي ﺑﻪ ﮐﺎر ﺑﺮده ﺑﺎ ﺷﺮاﯾﻂ واﻗﻌﯽ آﺑﺨﻮان اﺳﺖ. ﺑﺎ ﺗﻮﺟﻪ ﺑﻪ ﻣﺤﺪودﯾﺖ ﻣﻨﺎﺑﻊ و اﻓﺖ ﺳﻄﺢ اﯾﺴﺘﺎﺑﯽ و ﻫﻤﭽﻨﯿﻦ ﺣﺴﺎﺳﯿﺖ وﯾﮋه اﯾﻦ دﺷﺖ در ﺗﺄﻣﯿﻦ آب ﺷﺮب، ﮐﺸﺎورزي و ﺻﻨﻌﺖ ﺷﻬﺮ ﻫﻤﺪان و ﺑﻬﺎر، ﺗﺼﻤﯿﻢ ﮔﯿﺮي براي مديريت آب زيرزميني در محدوده دشت الزامي است.

This research has been conducted with the aim to evaluate the vulnerability of Hamedan’s Dasht-e Bahar groundwater and to compare the zonings through utilizing DRASTIC, GODS, and A VI methods. The data were turned into raster layers in the GIS software after exploring the region’s environment and collecting the data of 70 wells located in the under- study area. Each method was weighed, ranked and classified after the raster layers obtained from the wells’ locations and the essential data were prepared. The vulnerability maps of the three methods were then compared with each other. The results obtained from the DRASTIC method, which is almost the most thorough method for evaluating the groundwater vulnerability potential, estimated that 97.41 percent of the areas have low vulnerability and 68.57 percent of the areas are moderately vulnerable. The results of GODS method indicate that the under- study plain is located in two low and moderate vulnerability classes of 50.81 and 50.18 percent respectively. The results of the A VI method also indicate that 42.53 percent of the aquifer has a low pollution potential and 58.46 percent of it has a moderate pollution potential. Dasht-e Bahar is categorized in low and moderate vulnerability groups however the extent of the development of the vulnerability zones are different. The vulnerability areas were more consistent in DRASTIC and GODS methods and the DRASTIC method estimated the vulnerability of Dasht-e Bahar’s groundwater to be greater than what the GODS method had estimated.