مدل‌سازي بار فسفات ورودي به درياي خزر از حوزه آبخيز تجن با استفاده از مدل ارزيابي آب و خاك

Modelling of Input Phosphate Load to the Caspian Sea from Tajan Watershed Using Soil and Water Assesment Tool

زﻣﯿﻨﻪ و ﻫﺪف: ﺗﻮﺳﻌﻪ ﮐﺸﺎورزي ﺑﺮاي ﭘﺎﺳﺨﮕﻮﯾﯽ ﺑﻪ ﻧﯿﺎز روز اﻓﺰون ﻏﺬا ﺳﺒﺐ ﻣﺼﺮف ﺑﯿﺸﺘﺮ ﮐﻮدﻫﺎي ﺷﯿﻤﯿﺎﯾﯽ و درﻧﺘﯿﺠﻪ آﻟﻮدﮔﯽ اﮐﻮﺳﯿﺴﺘﻢﻫﺎي آﺑﯽ ﮔﺮدﯾﺪه اﺳﺖ. ﺑﻨﺎﺑﺮاﯾﻦ ﺑﺮآورد ﻣﻮاد ﻣﻐﺬي ﻣﻨﺎﺑﻊ ﻏﯿﺮ ﻧﻘﻄﻪاي، ﺑﺮرﺳﯽ ﻣﯿﺰان ﺗﺠﺎوز آنﻫﺎ از ﺣﺪ ﻣﺠﺎز و ﻧﯿﺰ ارزﯾﺎﺑﯽ ﺳﻬﻢ آﻟﻮدﮔﯽ ﻓﺴﻔﺎت ورودي از ﺣﻮزه آﺑﺨﯿﺰ ﺗﺠﻦ ﺑﻪ درﯾﺎي ﺧﺰر ﯾﮏ اوﻟﻮﯾﺖ ﺑﻪ ﻣﻨﻈﻮر ارزﯾﺎﺑﯽ ﺳﻼﻣﺖ ﺣﻮﺿﻪ اﺳﺖ. روش ﺑﺮرﺳﯽ: ﻟﺬا در اﯾﻦ ﻣﻄﺎﻟﻌﻪ از اﺑﺰار ارزﯾﺎﺑﯽ آب و ﺧﺎك )SWAT( ﺑﺮاي ﺷﺒﯿﻪ ﺳﺎزي ﻓﺴﻔﺎت ﻃﯽ ﺳﺎل ﻫﺎي 2001 ﺗﺎ 2014 در ﺣﻮزه آﺑﺨﯿﺰ ﺗﺠﻦ اﺳﺘﻔﺎده ﺷﺪه اﺳﺖ. ﯾﺎﻓﺘﻪ ﻫﺎ: ﻧﺘﺎﯾﺞ ﻣﺪل واﺳﻨﺠﯽ ﺷﺪه ﻧﺸﺎن داد ﺑﺎر ﺳﺎﻻﻧﻪ ﻓﺴﻔﺎت از ﺳﺎل 2001 ﺗﺎ 2014 از ﺣﺪود 29000 ﺗﺎ 102900 ﮐﯿﻠﻮﮔﺮم در ﺧﺮوﺟﯽ ﺣﻮزه آﺑﺨﯿﺰ ﻣﺘﻔﺎوت اﺳﺖ. ﺑﺎر ﻓﺴﻔﺎت در زﻣﺴﺘﺎن و ﭘﺎﯾﯿﺰ 98 درﺻﺪ از ﮐﻞ ﺑﺎر ﺳﺎﻻﻧﻪ ﻓﺴﻔﺎت را ﺑﻪ ﺧﻮد اﺧﺘﺼﺎص داد. ﺑﺎﻻﺗﺮﯾﻦ ﺳﻄﺢ ﻓﺴﻔﺎت در دوره ﻣﻮرد ﻣﻄﺎﻟﻌﻪ در ﻣﺎه ﻓﻮرﯾﻪ )ﺑﻪ ﻃﻮر ﻣﺘﻮﺳﻂ 11621 ﮐﯿﻠﻮﮔﺮم( و ﮐﻢ ﺗﺮﯾﻦ در ﻣﺎه ژوﺋﻦ )ﺑﻪ ﻃﻮر ﻣﺘﻮﺳﻂ 0/7 ﮐﯿﻠﻮﮔﺮم( ﺑﻮد. ﻫﻢﭼﻨﯿﻦ از ﻣﻘﺎﯾﺴﻪ ﻏﻠﻈﺖ ﻫﺎي ﺑﻪ دﺳﺖ آﻣﺪه ﺑﺎ اﺳﺘﺎﻧﺪاردﻫﺎي ﮐﯿﻔﯿﺖ آب ﻣﯽ ﺗﻮان ﻧﺘﯿﺠﻪ ﮔﺮﻓﺖ ﮐﻪ ﻏﻠﻈﺖ ﻓﺴﻔﺎت در اﮐﺜﺮ زﯾﺮﺣﻮﺿﻪ ﻫﺎ ﺑﺎﻻﺗﺮ از ﺣﺪ اﺳﺘﺎﻧﺪارد ﮐﯿﻔﯿﺖ آب آﺷﺎﻣﯿﺪﻧﯽ ﺑﺮاي ﺳﻼﻣﺖ اﻧﺴﺎﻧﯽ )0/2 ﻣﯿﻠﯽ ﮔﺮم در ﻟﯿﺘﺮ( اﺳﺖ. ﺑﻨﺎﺑﺮاﯾﻦ اﮐﺜﺮا زﯾﺮﺣﻮﺿﻪﻫﺎ در ﻣﻨﻄﻘﻪ ﻣﻮرد ﻣﻄﺎﻟﻌﻪ ﻧﯿﺎزﻣﻨﺪ ﮐﺎﻫﺶ ﺑﺎر ﻓﺴﻔﺎت ﻣﯽ ﺑﺎﺷﻨﺪ و ﻣﯽﺑﺎﯾﺴﺖ اﯾﻦ زﯾﺮﺣﻮﺿﻪﻫﺎ در ﺑﺮﻧﺎﻣﻪﻫﺎي ﻣﺪﯾﺮﯾﺘﯽ ﺑﻬﺒﻮد ﮐﯿﻔﯿﺖ آب ﺣﻮﺿﻪ در اوﻟﻮﯾﺖ ﻗﺮار ﮔﯿﺮﻧﺪ. ﺑﺤﺚ و ﻧﺘﯿﺠﻪ ﮔﯿﺮي: ﻧﺘﺎﯾﺞ ﻧﺸﺎن داد ﮐﻪ ﻣﺪل SWAT ﻣﯽﺗﻮاﻧﺪ راﻫﻨﻤﺎي ﺧﻮﺑﯽ ﺑﺮاي اﺳﺘﺮاﺗﮋيﻫﺎي ﮐﺎﻫﺶ ﺑﺎر آﻟﻮدﮔﯽﻫﺎ ﺑﺎ

Background and Objective: The development of agriculture to respond to growing need for food causes more consumption of chemical fertilizers and water ecosystems pollution. Therefore, in this study estimation of nutrients from non-point sources, the amount of exceed than standard level, evaluation of phosphate pollution input from Tajan watershed to the Caspian Sea is a priority for watershed health assessment. Method: In this study, the Soil and Water Assessment Tool (SWAT) for the simulation of phosphate during the years from 2001 to 2012 were used. Findings: The results showed that annual phosphate during 2001 to 2014, from about 29,000 to 102,900 kg in watershed output were different. Phosphate in winter and autumn were allocated 98 percent of total annual load. The highest levels of phosphate were in February (an average of 11 621 kg) and lowest in June (average 0.7 kg). Also, phosphate concentration was higher than drinking water quality standards (0.2 mg/l) in most subbasins. Discussion and Conclusion: It is necessary to reduce the phosphatein in these subbasins. They should be prioritized in water quality management programs. Also, results showed that the SWAT model can be a useful tool for pollution reduction strategies.