بررسي خودپالايي و مدل‌سازي تغييرات نيتروژن و فسفر در طول رودخانه دز (بازه سد دز تا پل بند قير)

An Investigation into Self-Purification and Modeling of Changes in Nitrogen and Phosphor along Dez River (The Distance between Dez Dam and Band Ghir Bridge

زﻣﯿﻨﻪ و ﻫﺪف: ﺑﺮاي ﺗﻌﯿﯿﻦ ﻋﮑﺲاﻟﻌﻤﻞ ﻗﺎﺑﻞاﻧﺘﻈﺎر رودﺧﺎﻧﻪ ﺑﺮ اﺛﺮ ورود آﻻﯾﻨﺪه، اﺳﺘﻔﺎده از ﻣﺪلﻫﺎي رﯾﺎﺿﯽ ﺿـﺮوري اﺳـﺖ. اﯾـﻦ ﻣـﺪل ﻫـﺎ ﻗﺎدرﻧﺪ آﺛﺎر ﺑﺎرﮔﺬاريﻫﺎي ﻣﻮﺟﻮد و آﯾﻨﺪه را ﺷﺒﯿﻪﺳﺎزي ﻧﻤﻮده و ﻣﺪﯾﺮان و ﻣﺴﺌﻮﻻن را در ﺗﺼﻤﯿﻢﮔﯿـﺮي ﻫـﺎي ﺧـﻮد ﯾـﺎري ﻧﻤﺎﯾﻨـﺪ. ﻫـﺪف از ﻣﻄﺎﻟﻌﻪ ﺣﺎﺿﺮ ﺷﺒﯿﻪﺳﺎزي و آﮔﺎﻫﯽ از روﻧﺪ ﺗﻐﯿﯿﺮات ﻧﯿﺘﺮوژن و ﻓﺴﻔﺮ در ﻃﻮل رودﺧﺎﻧﻪ ذر )ﺑﺎزه ﺳﺪ دز ﺗﺎ ﭘﻞ ﺑﻨﺪ ﻗﯿﺮ ( ﺑﺎ ﻣﺪل Qual2kw و ﻫﻤﭽﻨﯿﻦ ﻣﺤﺎﺳﺒﻪ درﺻﺪ ﺧﻮدﭘﺎﻻﯾﯽ رودﺧﺎﻧﻪ ﻣﯽﺑﺎﺷﺪ. روش ﺑﺮرﺳﯽ: در اﯾﻦ ﻣﻄﺎﻟﻌﻪ ﺑﺎ ﺗﻮﺟﻪ ﺑﻪ آﻣﺎر و دادهﻫﺎي اﻧﺪازهﮔﯿﺮي ﺷﺪه در ﻣﻮرد ﮐﯿﻔﯿﺖ آب رودﺧﺎﻧﻪ دز در ﺳﻪ اﯾﺴﺘﮕﺎه دزﻓﻮل، ﺣﺮﻣﻠﻪ و ﺑﺎﻣﺪژ و ﻣﻘﺎﯾﺴﻪ آﻧﻬﺎ ﺑﺎ اﺳﺘﺎﻧﺪاردﻫﺎي ﻣﻮﺟﻮد، وﺿﻌﯿﺖ اﯾﻦ رودﺧﺎﻧﻪ ﻣﻮرد ﺑﺮرﺳﯽ ﻗﺮار ﮔﺮﻓﺖ. ﻣﺪل ﺷﺒﯿﻪﺳﺎز رودﺧﺎﻧﻪ ﺑﺎ ورود ﻣﺸﺨﺼﺎت ﮐﻤﯽ و ﮐﯿﻔﯽ در اﯾﺴﺘﮕﺎهﻫﺎي ﺗﻌﯿﯿﻦ ﺷﺪه و ﭘﺴﺎبﻫﺎي ورودي ﺑﻪ آن در ﻓﺼﻞ ﮐﻢ آب ﺳﺎﺧﺘﻪ و ﮐﺎﻟﯿﺒﺮه ﺷﺪ. ﯾﺎﻓﺘﻪﻫﺎ: ﻧﺘﺎﯾﺞ ﻧﺸﺎن داد ﮐﻪ ﻗﺪرت ﺧﻮدﭘﺎﻻﯾﯽ رودﺧﺎﻧﻪ ﮐﻢ اﺳﺖ، ﺑﯿﺸﺘﺮﯾﻦ ﻣﻘﺪار ﺧﻮدﭘﺎﻻﯾﯽ ﻣﺮﺑـﻮط ﺑـﻪ ﭘـﺎراﻣﺘﺮ N-NH4 در ﺳـﺎل 2014 ﻣﻌﺎدل 45% ﻣﯽﺑﺎﺷﺪ. ﻣﯿﺰان ﻓﺴﻔﺮ ﻏﯿﺮآﻟﯽ در ﻃﻮل رودﺧﺎﻧﻪ روﻧﺪ رو ﺑﻪ رﺷﺪي داﺷﺘﻪ اﺳﺖ. ﺑﺤﺚ و ﻧﺘﯿﺠﻪﮔﯿﺮي: ﻣﯿﺰان ﻧﯿﺘﺮوژن ﻧﯿﺘﺮاﺗﯽ و ﻧﯿﺘﺮوژن آﻣﻮﻧﯿﺎﮐﯽ در ﺑﺎزه ﮐﯿﻠﻮﻣﺘﺮ 173 ﺗﺎ 90 رودﺧﺎﻧﻪ، ﺑﻪ ﻋﻠـﺖ ﻫﺠـﻮم ﻓﺎﺿـﻼب ﻫـﺎ روﻧـﺪ اﻓﺰاﯾﺸﯽ دارد. ﺑﻬﺘﺮﯾﻦ ﺷﺒﯿﻪﺳﺎزي ﺑﺮاي ﭘﺎراﻣﺘﺮ N-NH4در ﺳﺎل 2016ﻣﯽ ﺑﺎﺷﺪ ﮐﻪ ﺧﻄﺎي اﺳﺘﺎﻧﺪارد آن ﻣﻌﺎدل 0/02 ﻣﯽﺑﺎﺷﺪ.

Background and Objective: It is necessary to use mathematical models to determine the expected reaction of a river to the effects of entrance of pollutants. Such models can simulated the effects of current and future loadings and help managers and authorities make their final decisions. The purpose of this study is to simulate and be aware of the trend of nitrogen and phosphorus changes along the Dez River (Dez Dam to Ghir Dam Bridge) using the Qual2kw model and also to calculate the percentage of river self-purification. Method: The present study was aimed at measuring and comparing the data of the quality of Dez River water collected from three stations. Self-purification model of the river was determined by inserting qualitative and quantitative data retrieved from the stations, and the entering wastewaters in the dry season were created and calibrated. Findings: The results of the present study showed that the river has poor self-purification power. The highest self-purification power was related to N-NH4 parameter in 2014 (45%). The level of non-organic phosphor along the river had an increasing trend. Discussion and Conclusion: The level of nitrate nitrogen and ammonia nitrogen within the distance of 173 to 90 km of the river had an increasing trend due to influx of sewage. The best modelling for N-NH4 parameter was related to 2016 with a standard error of 0.02.