بررسي اثر سد كرخه بر منابع آب زيرزميني با استفاده از مدل GMS (مطالعه موردي: دشت عباس،دهلران)

Investigation of the Effect of Karkheh Dam on Ground Water Resources Using GMS Model (Case study: Dasht-Abbas, Dehloran)

زﻣﯿﻨﻪ و ﻫﺪف: ﺑﺎرزﺗﺮﯾﻦ اﺛﺮ ﺳﺪﻫﺎ، ﺗﻐﯿﯿﺮ رژﯾﻢ ﻫﯿﺪروﻟﻮژﯾﮑﯽ ﻣﻨﺎﻃﻖ ﻣﺠﺎور ﺧﻮد اﺳﺖ ﮐﻪ از ﺟﻤﻠﻪ اﯾﻦ ﺗﻐﯿﯿﺮات ﻣﯽ ﺗﻮان ﺑﻪ ﺗﻐﯿﯿﺮ در ﺳﻄﺢ اﺳﺎس آﺑﺨﻮان ﻫﺎي ﻣﺠﺎور اﺷﺎره ﻧﻤﻮد. در اﯾﻦ ﺗﺤﻘﯿﻖ ﺳﺪ ﮐﺮﺧﻪ و ﺗﺎﺛﯿﺮ آن ﺑﺮ ﻧﻮﺳﺎﻧﺎت ﺳﻄﺢ آب زﯾﺮزﻣﯿﻨﯽ دﺷﺖ ﻋﺒﺎس ﻣﻮرد ﺑﺮرﺳﯽ ﻗﺮار ﮔﺮﻓﺖ اﺳﺖ. روش ﺑﺮرﺳﯽ: در اﯾﻦ ﺗﺤﻘﯿﻖ از آﻣﺎر اﯾﺴﺘﮕﺎه ﻫﺎي ﻣﺠﺎور ﻣﻨﻄﻘﻪ و 192 ﭼﺎه ﺑﻬﺮه ﺑﺮداري و 24 ﭼﺎه ﭘﯿﺰوﻣﺘﺮي اﺳﺘﻔﺎده ﺷﺪ. ﻣﺪل ﺳﺎزي ﻋﺪدي آب ﻫﺎي زﯾﺮزﻣﯿﻨﯽ ﺑﻪ وﺳﯿﻠﻪ ﻧﺮم اﻓﺰار GMS در آﺑﺨﻮان دﺷﺖ ﻋﺒﺎس در ﺟﻨﻮب اﺳﺘﺎن اﯾﻼم در ﺳﺎل آﺑﯽ 89-90 اﻧﺠﺎم ﯾﺎﻓﺘﻪ اﺳﺖ. اﯾﻦ ﻣﺪل در دو ﺣﺎﻟﺖ ﻣﺎﻧﺪﮔﺎر )ﺳﻪ ﻣﺎه( و ﻏﯿﺮ ﻣﺎﻧﺪﮔﺎر )12 ﻣﺎه( ﺑﺮاي ﯾﮏ و ﻧﯿﻢ ﺳﺎل واﺳﻨﺠﯽ و ﺳﭙﺲ ﺑﺮاي ﯾﮏ ﺳﺎل آﺑﯽ ﺻﺤﺖ ﺳﻨﺠﯽ ﮔﺮدﯾﺪ. ﯾﺎﻓﺘﻪﻫﺎ: ﻧﺘﺎﯾﺞ ﺣﺎﺻﻞ از واﺳﻨﺠﯽ، ﺣﺎﮐﯽ از ﺷﺒﯿﻪ ﺳﺎزي ﻣﻄﻠﻮب آﺑﺨﻮان دﺷﺖ ﻋﺒﺎس و اﺧﺘﻼف اﻧﺪك ﻣﻘﺎدﯾﺮ ﻣﺸﺎﻫﺪه اي و ﻣﺤﺎﺳﺒﺎﺗﯽ ﺗﺮاز ﺳﻄﺢ اﯾﺴﺘﺎﺑﯽ اﺳﺖ. ﻫﻤﭽﻨﯿﻦ، ﻧﺘﺎﯾﺞ ﺑﯿﻼن آﺑﯽ ﻧﺸﺎن داد ﮐﻪ ﺳﻄﺢ آب زﯾﺮزﻣﯿﻨﯽ در ﺳﺎل ﻫﺎي ﻗﺒﻞ از ورود آب ﺳﺪ ﮐﺮﺧﻪ 7/03- و ﺑﻌﺪ از ﺗﮑﻤﯿﻞ ﮐﺎﻧﺎل ﻫﺎي آﺑﺮﺳﺎﻧﯽ ﺑﯿﻼن دﺷﺖ ﻣﺜﺒﺖ و ﻣﻘﺪار آن ﺑﻪ 26/50 ﻣﯿﻠﯿﻮن ﻣﺘﺮ ﻣﮑﻌﺐ در ﺳﺎل آﺑﯽ 89-90 اﻓﺰاﯾﺶ ﯾﺎﻓﺘﻪ اﺳﺖ. ﻟﺬا ﺳﺪ ﮐﺮﺧﻪ اﺛﺮ ﻣﺜﺒﺘﯽ ﺑﺮ ﺑﯿﻼن آب زﯾﺮزﻣﯿﻨﯽ دﺷﺖ دارد. ﺑﺤﺚ و ﻧﺘﯿﺠﻪﮔﯿﺮي: از ﺑﺮرﺳﯽ ﺑﯿﻼن آب زﯾﺮزﻣﯿﻨﯽ دﺷﺖ ﻋﺒﺎس ﭼﻨﯿﻦ ﻧﺘﯿﺠﻪ ﮔﯿﺮي ﻣﯽ ﺷﻮد ﮐﻪ ﻣﺪل ﮐﺎﻟﯿﺒﺮه ﺷﺪه در ﺣﺎﻟﺖ ﭘﺎﯾﺪار و ﻧﺎﭘﺎﯾﺪار ﺑﺎ دﻗﺖ زﯾﺎدي ﺗﻮاﻧﺴﺘﻪ اﺳﺖ، ﺳﻄﺢ اﯾﺴﺘﺎﺑﯽ ﭼﺎه ﻫﺎي ﭘﯿﺰوﻣﺘﺮي را ﺷﺒﯿﻪ ﺳﺎزي ﮐﻨﺪ. ﻫﯿﺪروﮔﺮاف ﭼﺎه ﻫﺎي ﭘﯿﺰوﻣﺘﺮي دﺷﺖ ﻋﺒﺎس ﻧﺸﺎن داد ﮐﻪ ﺳﻄﺢ اﯾﺴﺘﺎﺑﯽ دﺷﺖ ﻋﺒﺎس رو ﺑﻪ اﻓﺰاﯾﺶ اﺳﺖ. ﻧﺘﺎﯾﺞ ﻣﺪل ﺳﺎزي ﺑﯿﻼن آب زﯾﺮ زﻣﯿﻨﯽ ﻧﺸﺎن داد ﮐﻪ ﺗﻐﯿﯿﺮات ذﺧﯿﺮه ﻧﺎﺷﯽ از ﺑﯿﻼن آﺑﯽ دﺷﺖ ﻋﺒﺎس ﻣﺜﺒﺖ اﺳﺖ و ﺳﯿﺮ ﺻﻌﻮدي ﻫﯿﺪروﮔﺮاف دﺷﺖ، اﻓﺰاﯾﺶ ﺳﻄﺢ اﯾﺴﺘﺎﺑﯽ و ﺑﺤﺮان ﻣﻨﺎﻃﻖ ﺗﺒﺨﯿﺮي ﺑﻮﺟﻮد آﻣﺪه را ﻧﺸﺎن ﻣﯽ دﻫﺪ.

Background and Objective: The most obvious effect of the dams is the change of the hydrological regime of the adjacent areas, among which these changes can be referred to the change in the base level of the adjacent aquifers. In this study, Karkheh dam and its effect on groundwater fluctuations in Abbas plain have been studied. Method: In this study, the statistics of nearby stations, 192 exploitation wells and 24 piezometric wells were used. Numerical modeling of groundwater has been done by GMS software in Dasht-Abbas aquifer in the south of Ilam province in the water year of 2011-2012. This model was calibrated in two permanent (three months) and non-permanent (12 months) for one and a half years and then for one year. Findings: The results of calibration indicate the optimal simulation of Dasht-Abbas aquifer and small differences in observational and computational values of water table level. Also, the results of water balance showed that the groundwater level in the years before the arrival of water Karkheh dam - 7.03 and after the completion of water supply channels of the positive plain balance and its amount has increased to 26.50 million cubic meters in the water year 2011-2012. Therefore, Karkheh Dam has a positive effect on the groundwater balance of the plain. Discussion and Conclusion: From the study of groundwater balance in Dasht- Abbas, it is concluded that the calibrated model in stable and unstable state has been able to simulate the water level of piezometric wells with great accuracy. The hydrograph of the piezometric wells of Dasht-Abbas showed that the water level of Dasht-Abbas is increasing. The results of groundwater balance modeling showed that the reserve changes due to the water balance of Abbas plain are positive and show the upward trend of the plain hydrograph, increasing water table and the evaporation crisis.