ارزيابي اثر تأمين نياز آبي شرب و كشاورزي آبخوان ساري- نكا بر حركت جبهه شوري با بهره‌برداري از سد گلورد

Evaluating the effect of supplying drinking water and agriculture water of Sari-Neka aquifer on the salinity movement with the utilization of Gelvard dam

ﺑﺎ رﺷﺪ ﺳﺮﯾﻊ اﻗﺘﺼﺎد در ﻣﻨﺎﻃﻖ ﺳﺎﺣﻠﯽ، ﺗﻘﺎﺿﺎ ﺑﺮاي ﻣﻨﺎﺑﻊ آب و ﺑﻬﺮهﺑﺮداري از آبﻫﺎي زﯾﺮزﻣﯿﻨﯽ اﻓﺰاﯾﺶ ﯾﺎﻓﺘﻪ اﺳﺖ و اﯾﻦ اﻣﺮ ﻣﻮﺟﺐ اﺧﺘﻼل در ﺗﻌﺎدل ﺑﯿﻦ آبﺷﻮر و ﺷﯿﺮﯾﻦ در آﺑﺨﻮانﻫﺎي ﺳﺎﺣﻠﯽ و در ﻧﺘﯿﺠﻪ ﻣﻨﺠﺮ ﺑﻪ ﻧﻔﻮذ آب ﺷﻮر ﺑﻪ آبﻫﺎي زﯾﺮزﻣﯿﻨﯽ ﺧﻮاﻫﺪ ﺷﺪ. در ﭘﮋوﻫﺶ ﺣﺎﺿﺮ ﻣﺪل ﻋﺪدي ﺟﺮﯾﺎن و ﻧﻔﻮذ ﺷﻮري در آﺑﺨﻮان ﺳﺎﺣﻠﯽ ﺳﺎري- ﻧﮑﺎ ﺑﺎ اﺳﺘﻔﺎده از ﻧﺮماﻓﺰار GMS ﺷﺒﯿﻪﺳﺎزي ﺷﺪه اﺳﺖ. واﺳﻨﺠﯽ ﻣﺪل ﺑﺮاي ﺗﺮاز آب زﯾﺮزﻣﯿﻨﯽ و ﻏﻠﻈﺖ ﺷﻮري از ﻣﻬﺮ 1389 ﺗﺎ ﺷﻬﺮﯾﻮر 1393 ﺻﻮرت ﭘﺬﯾﺮﻓﺘﻪ اﺳﺖ. ﻣﺪل واﺳﻨﺠﯽﺷﺪه ﺑﺎ اﺳﺘﻔﺎده از اﻃﻼﻋﺎت در دﺳﺘﺮس از ﻣﻬﺮ 1393 ﺗﺎ ﺷﻬﺮﯾﻮر 1394 ﺑﺮاي ﺗﺮاز آب زﯾﺮزﻣﯿﻨﯽ و ﻏﻠﻈﺖ ﺷﻮري ﺻﺤﺖﺳﻨﺠﯽ ﮔﺮدﯾﺪه اﺳﺖ. ﺿﺮﯾﺐ ﻫﻤﺒﺴﺘﮕﯽ در ﻣﺮﺣﻠﻪ واﺳﻨﺠﯽ ﻣﺎﻧﺪﮔﺎر، ﻏﯿﺮﻣﺎﻧﺪﮔﺎر و ﺻﺤﺖﺳﻨﺠﯽ در ﻣﺪل ﮐﻤﯽ ﺑﻪﺗﺮﺗﯿﺐ ﺑﺮاﺑﺮ 0/99، 0/98 و 0/97 ﺑﻪدﺳﺖ آﻣﺪ. ﻫﻤﭽﻨﯿﻦ اﯾﻦ ﺿﺮﯾﺐ در ﻣﺪل اﻧﺘﻘﺎل در ﻣﺮﺣﻠﻪ واﺳﻨﺠﯽ ﻏﯿﺮﻣﺎﻧﺪﮔﺎر و ﺻﺤﺖﺳﻨﺠﯽ ﺑﻪﺗﺮﺗﯿﺐ ﺑﻪ ﻣﯿﺰان 0/83 و 0/87 ﺑﺮآورد ﺷﺪ. ﭘﺲ از ﺻﺤﺖﺳﻨﺠﯽ ﻣﺪل و ﺑﺎ ﻓﺮض ﺛﺎﺑﺖ ﻣﺎﻧﺪن ﺷﺮاﯾﻂ ﻫﯿﺪروژﺋﻮﻟﻮژﯾﮑﯽ آﺑﺨﻮان، ﻧﺘﺎﯾﺞ ﭘﯿﺶﺑﯿﻨﯽ ﻣﺪل ﻃﯽ ﺷﺶ ﺳﺎل آﯾﻨﺪه ﺑﯿﺎنﮔﺮ ﻫﺠﻮم ﺑﯿﺶﺗﺮ آب ﺷﻮر در آﺑﺨﻮان ﺳﺎﺣﻠﯽ ﻣﻮرد ﻣﻄﺎﻟﻌﻪ اﺳﺖ. در اداﻣﻪ ﺑﺎ ﺗﻮﺟﻪ ﺑﻪ اﺣﺪاث ﺳﺪ ﮔﻠﻮرد ﺑﺮ روي رودﺧﺎﻧﻪ ﻧﮑﺎرود، ﺗﺄﺛﯿﺮ ﺳﺪ ﺑﺮ آﺑﺨﻮان ﺳﺎري- ﻧﮑﺎ در ﺷﺮاﯾﻂ اﻗﻠﯿﻤﯽ ﻧﺮﻣﺎل، ﺧﺸﮑﺴﺎﻟﯽ و ﺗﺮﺳﺎﻟﯽ ﻣﻮرد ﺑﺮرﺳﯽ ﻗﺮار ﮔﺮﻓﺘﻪ اﺳﺖ. ﻧﺘﺎﯾﺞ ﻧﺸﺎن داد ﮐﻪ در ﺷﺮاﯾﻂ ﺧﺸﮑﺴﺎﻟﯽ ﺣﺮﮐﺖ ﺧﻂ ﻫﻢﻏﻠﻈﺖ 50 درﺻﺪ ﺷﻮري ﺑﺮاي ﭘﺎراﻣﺘﺮ TDS ﻧﺴﺒﺖ ﺑﻪ اﻧﺘﻬﺎي دوره ﭘﯿﺶﺑﯿﻨﯽ 5/98 درﺻﺪ اﻓﺰاﯾﺶ ﺧﻮاﻫﺪ داﺷﺖ. ﻫﻤﭽﻨﯿﻦ در ﺷﺮاﯾﻂ ﺗﺮﺳﺎﻟﯽ ﺣﺮﮐﺖ ﺧﻂ ﻫﻢﻏﻠﻈﺖ 50 درﺻﺪ ﺷﻮري ﺑﻪ ﻣﯿﺰان 2/94 درﺻﺪ ﮐﺎﻫﺶ ﺧﻮاﻫﺪ ﯾﺎﻓﺖ.

With the fast-growing economy in the coastal regions, the demands for water resources and the exploitation of groundwater have been increased. Consequently, the established balance between freshwater and seawater has been disturbed and hence resulted in extensive seawater intrusion into groundwater. In this paper, the flow model and saltwater intrusion in the Sari-Neka aquifer is simulated using the GMS model. The model is calibrated for four years Between October 2010 and September 2014, both in terms of groundwater levels and TDS concentration. The calibrated model is validated for the next year in terms of groundwater levels and TDS concentration with the available data for October 2014 and September 2015. The values of the correlation coefficient in the steady-state model, transient model and validation model in the flow model are obtained 0/99, 0/98 and 0/97 respectively. The values of the correlation coefficient in the transport model are obtained 0/83 and 0/87 in the transient model and validation model, respectively. After the validated model and assuming all the hydrogeologic conditions remain, a predictive 6-year simulation run indicates that further seawater intrusion into the coastal aquifer can occur in the study area. The effects of the Gelvard dam on the quality of groundwater in the Sari-Neka aquifer in normal, drought and wet conditions also were investigated. The results show that under drought conditions the 50% iso-concentration contour movement for TDS will increase by 5/98 %. In wet conditions, the 50% iso-concentration contour movement will be reduced by 2/94%.