پديد آورندگان :
شادفر, صمد سازمان تحقيقات، آموزش و ترويج كشاورزي تهران - پژوهشكده حفاظت خاك و آبخيزداري , عرب خدري, محمود سازمان تحقيقات، آموزش و ترويج كشاورزي تهران - پژوهشكده حفاظت خاك و آبخيزداري , نبي پي لشكريان, سعيد سازمان تحقيقات، آموزش و ترويج كشاورزي تهران - پژوهشكده حفاظت خاك و آبخيزداري
چكيده فارسي :
ﺮﺳﺎﯾﺶ ﺗﺸﺪﯾﺪي ﺧﺎك و ﺗﻮﻟﯿﺪ و اﻧﺘﻘﺎل ﻣﻘﺎدﯾﺮ زﯾﺎد رﺳﻮب از ﻣﻌﻀﻼت ﻣﻬﻢ ﺑﺴﯿﺎري از ﻣﻨﺎﻃﻖ ﮐﺸﻮر اﯾﺮان اﺳﺖ. ﺑﺮاي ﮐﺎﻫﺶ اﺛﺮات ﺳﻮء اﯾﻦ ﻣﻌﻀﻞ از ﻃﺮﯾﻖ اﻧﺠﺎم اﻗﺪاﻣﺎت ﺣﻔﺎﻇﺖ ﺧﺎك و آﺑﺨﯿﺰداري، اﻃﻼع از ﻣﯿﺰان ﻓﺮﺳﺎﯾﺶ ﺧﺎك و ﺗﻮﻟﯿﺪ رﺳﻮب و ﺑﻪ ﻋﺒﺎرﺗﯽ، ﺷﻨﺎﺳﺎﯾﯽ ﻣﻨﺎﻃﻖ ﺑﺤﺮاﻧﯽ ﺿﺮورت دارد. ﺑﺎ ﺗﻮﺟﻪ ﺑﻪ ﻓﻘﺪان اﯾﺴﺘﮕﺎه اﻧﺪازهﮔﯿﺮي در ﺧﺮوﺟﯽ آﺑﺨﯿﺰﻫﺎي ﮐﻮﭼﮏ، ﻣﺪل ﻫﺎي ﺗﺠﺮﺑﯽ اﺑﺰار ﻣﻨﺎﺳﺒﯽ ﺑﺮاي ﺗﺨﻤﯿﻦ ﻓﺮﺳﺎﯾﺶ ﺧﺎك و رﺳﻮب دﻫﯽ ﻫﺴﺘﻨﺪ. ﯾﮑﯽ از اﯾﻦ روش ﻫﺎ ﮐﻪ ﺑﺮ اﺳﺎس دادهﻫﺎي رﺳﻮب ﻣﻨﺎﻃﻖ ﻣﺪﯾﺘﺮاﻧﻪاي اﺑﺪاع ﺷﺪه، ﻣﺪل ﺗﺠﺮﺑﯽ ﻧﻤﺮه دﻫﯽ ﻓﺎﮐﺘﻮرﯾﻞ FSM اﺳﺖ. ﺑﺮ ﻫﻤﯿﻦ اﺳﺎس، ﻫﺪف اﺻﻠﯽ اﯾﻦ ﭘﮋوﻫﺶ، ﺑﺮرﺳﯽ ﻣﯿﺰان ﻫﻢ ﺧﻮاﻧﯽ ﺑﺮآوردﻫﺎي اﯾﻦ ﻣﺪل ﺗﺠﺮﺑﯽ و ﻣﻘﺪار ﻣﺸﺎﻫﺪهاي رﺳﻮب در ﻣﻨﺎﻃﻖ ﻣﻨﺘﺨﺐ ﮐﺸﻮر اﺳﺖ. ﺑﻪ ﻫﻤﯿﻦ ﻣﻨﻈﻮر، 58 ﺣﻮﺿﻪ واﺟﺪ اﻃﻼﻋﺎت رﺳﻮب دﻫﯽ در اﺳﺘﺎن ﻫﺎي ﺳﻤﻨﺎن، ﻣﺮﮐﺰي، اﺻﻔﻬﺎن، ﭼﻬﺎرﻣﺤﺎل و ﺑﺨﺘﯿﺎري، آذرﺑﺎﯾﺠﺎن ﻏﺮﺑﯽ، ﻟﺮﺳﺘﺎن، ﻓﺎرس، ﮔﻠﺴﺘﺎن و ﺧﺮاﺳﺎن رﺿﻮي ﺑﺮاي ﻣﻘﺎﯾﺴﻪ ﺑﺎ ﻣﻘﺎدﯾﺮ ﺑﺮآوردي ﻣﺪل اﻧﺘﺨﺎب ﺷﺪﻧﺪ. ﺑﺮاي ﻣﺤﺎﺳﺒﻪ رﺳﻮب دﻫﯽ ﺣﻮﺿﻪ ﻫﺎ، ﻻﯾﻪ ﻫﺎي اﻃﻼﻋﺎﺗﯽ ﻻزم ﺑﺮاي ﻣﺪل FSM ﺑﺮرﺳﯽ و اﻣﺘﯿﺎزﻫﺎي ﻣﺮﺑﻮﻃﻪ داده ﺷﺪ. ﻣﻘﺎﯾﺴﻪ ﻧﺘﺎﯾﺞ ﻧﺸﺎن داد ﮐﻪ ﺗﻤﺎﻣﯽ ﺗﺨﻤﯿﻦ ﻫﺎي ﻣﺪل اﺻﻠﯽ ﻗﺒﻞ از واﺳﻨﺠﯽ، ﭼﻨﺪ ﺑﺮاﺑﺮ ﺑﯿﺸﺘﺮ از ﻣﻘﺎدﯾﺮ رﺳﻮب اﻧﺪازه ﮔﯿﺮي ﺷﺪه ﻣﺨﺎزن، 0/44 ﺗﺎ 459/64 ﺗﻦ ﺑﺮ ﮐﯿﻠﻮﻣﺘﺮ ﻣﺮﺑﻊ در ﺳﺎل اﺳﺖ. ﺑﻪﻣﻨﻈﻮر اﺻﻼح ﺿﺮاﯾﺐ، واﺳﻨﺠﯽ در ﻗﺎﻟﺐ دو ﺳﻨﺎرﯾﻮ، ﯾﮏ ﺑﺎر ﺑﺎ ﮐﻞ دادهﻫﺎ و ﺑﺎر دﯾﮕﺮ، ﭘﺲ از ﺗﻘﺴﯿﻢ ﺑﻪ ﺳﻪ ﻣﻨﻄﻘﻪ ﺟﻐﺮاﻓﯿﺎﯾﯽ اﻧﺠﺎم ﮔﺮﻓﺖ ﮐﻪ ﺳﺒﺐ ﺑﻬﺒﻮد ﻗﺎﺑﻞ ﺗﻮﺟﻪ ﺑﺮآوردﻫﺎ ﺷﺪ. ﺑﻪ ﻃﻮري ﮐﻪ ﺿﺮﯾﺐ ﮐﺎراﯾﯽ Nash‐Sutcliffe ﺑﺮاي ﮐﻞ اﯾﺴﺘﮕﺎهﻫﺎ، 0/39 و ﺑﺮاي ﻣﻨﺎﻃﻖ ﻣﺮﮐﺰي، زاﮔﺮس و ﺷﻤﺎل ﺷﺮﻗﯽ ﺑﻪ ﺗﺮﺗﯿﺐ 0/66 ،0/51 و 0/78 ﺑﻪ دﺳﺖ آﻣﺪ. ﺑﻪ ﻫﻤﯿﻦ دﻟﯿﻞ ﺗﻮﺻﯿﻪ ﻣﯽﺷﻮد ﮐﻪ از ﮐﺎرﺑﺮد ﻣﺪل FSM ﺑﺪون واﺳﻨﺠﯽ ﺧﻮدداري ﺷﻮد. ﻫﻤﭽﻨﯿﻦ، ﻃﺒﻖ ﻧﺘﺎﯾﺞ ﺑﻪ دﺳﺖ آﻣﺪه ﻣﯽ ﺗﻮان ﺟﻤﻊ ﺑﻨﺪي ﮐﺮد ﮐﻪ واﺳﻨﺠﯽ ﻣﻨﻄﻘﻪ اي ﻣﺪل ﺗﺠﺮﺑﯽ FSM، ﻧﺘﺎﯾﺞ ﺑﻬﺘﺮي دارد.
چكيده لاتين :
Accelerated soil erosion and the production and transfer of large amounts of sediment are considered as one of the most important issues in many parts of Iran. Having enough knowledge on soil erosion and sediment production as well as identification of critical areas are necessary in order to reduce the adverse effects of this problem through soil and water conservation measures. Due to lack of gauge stations in the outlets’ of small watersheds, empirical models are considered as the proper tools for estimating soil erosion and sedimentation. One of these methods which was developed based on Meditranean sediment data, is the Factorial Scoring Model (FSM). Towards this, the main objective of this research is to compare estimated vs. observed sediment yields in some selected regions of Iran. For this purpose, 58 small chatchments equipped by reservoirs in their outlets were selected in Semnan, Central, Isfahan, Chaharmahal and Bakhtiari, West Azarbaijan, Lorestan, Fars, Golestan and Khorasan Razavi Provinces. The comparison of the results showed that all estimates of the original model (before calibration) are several times bigger than observed values obtained by surveying (0.44 to 459.44 t.km-2.y-1). In order to correct the model coefficients for Iran, calibration was performed in two scenarios; once using all data and in the second secenario after allocating data into three geographic regions, which in both cases resulted in significant improvement of estimates. The Nash‐Sutcliffe Efficiency coefficient for all catchments was 0.39, and for Central, Zagros and Northeast regions were 51.1, 0.66 and 0.78, respectively. Based on obtained findings, the application of original FSM must be avoided in study areas. Instead, we strongly recommend using calibrated models based on observational values for different geographic regions.
