بررسی ویژگی‌های فرمی سطح زمین براساس شاخص‌های مورفومتری و با استفاده از gisمطالعه موردی: حوضۀ آبخیز فهلیان

ﺷﻨﺎﺧﺖ ﺧﺼﻮﺻﯿﺎت ﻓﯿﺰﯾﮑﯽ ﺣﻮﺿﮥ آﺑﺨﯿﺰ از اوﻟﯿﻦ ﮔﺎمﻫﺎﯾﯽ اﺳﺖ ﮐﻪ در ﺑﺮرﺳﯽﻫﺎی ﻣﻮرﻓﻮﻟﻮژﯾﮑﯽ و ﻫﯿﺪروﻟﻮژﯾﮑﯽ ﺿﺮورت دارد. اﯾﻦ ﭘﮋوﻫﺶ ﺳﻌﯽ دارد ﺑﺎ اﺳﺘﻔﺎده از ﺷﺎﺧﺺ ﻫﺎی ﻣﻮرﻓﻮﻣﺘﺮﯾﮏ وﯾﮋﮔﯽ ﻫﺎی ﻓﯿﺰﯾﮑﯽ و وﺿﻌﯿﺖ ﺷﮑﻠﯽ ﺳﻄﺢ زﻣﯿﻦ در ﺣﻮﺿﻪ آﺑﺨﯿﺰ ﻓﻬﻠﯿﺎن را ﻣﻮرد ﺑﺮرﺳﯽ ﻗﺮار دﻫﺪ. ﺑﻪ ﻫﻤﯿﻦ ﻣﻨﻈﻮر 6 ﺷﺎﺧﺺﻫﺎی ژﺋﻮﻣﻮرﻓﻮﻣﺘﺮﯾﮏ؛ اﻧﺤﻨﺎی ﮐﻞ، اﻧﺤﻨﺎی ﻧﯿﻤﺮخ، اﻧﺤﻨﺎی ﺳﻄﺢ، ﺷﺎﺧﺺ tri، ﺷﺎﺧﺺ tpi و ﺷﺎﺧﺺ twi اﻧﺘﺨﺎب و ﺑﺎ اﺳﺘﻔﺎده از رواﺑﻂ ﻣﺮﺑﻮط ﺑﻪ ﻫﺮ ﺷﺎﺧﺺ و ﺑﺎ ﺑﻬﺮهﮔﯿﺮی از اﮐﺴﺘﻨﺸﻦﻫﺎی ﻣﺮﺑﻮﻃﻪ در ﻧﺮماﻓﺰار 10/3 arcgis ﻧﻘﺸﻪﻫﺎی ﻫﺮﯾﮏ از اﯾﻦ ﺷﺎﺧﺺﻫﺎ ﺗﻬﯿﻪ ﺷﺪ. ﻧﺘﺎﯾﺞ ﺣﺎﺻﻞ از ﻣﺤﺎﺳﺒﻪ اﻧﺤﻨﺎی ﮐﻞ ﻧﺸﺎن ﻣﯽدﻫﺪ ﮐﻪ ﺑﯿﺶ از ﻧﯿﻤﯽ از ﺳﻄﺢ ﺣﻮﺿﻪ(52/80) دارای اﻧﺤﻨﺎی ﻣﻘﻌﺮ و 47/20 درﺻﺪ آن از اﻧﺤﻨﺎی ﻣﺤﺪب ﺑﺮﺧﻮردار ﻣﯽﺑﺎﺷﺪ. ﻫﻤﭽﻨﯿﻦ ﺣﺪ ﭘﺎﯾﯿﻦ و ﺑﺎﻻ ﺑﺮای اﻧﺤﻨﺎی ﺳﻄﺢ ﺑﻪ ﺗﺮﺗﯿﺐ 2/99- و 3/96 و ﺑﺮای اﻧﺤﻨﺎی ﻧﯿﻤﺮخ ﺑﻪ ﺗﺮﺗﯿﺐ 4/87- و 4/2 ﺑﺪﺳﺖ آﻣﺪ. ﺑﺮ ﻫﻤﯿﻦ اﺳﺎس ﺣﺪ ﭘﺎﯾﯿﻦ و ﺑﺎﻻی ﺷﺎﺧﺺ tpi ﮐﻪ ﺣﺎﻟﺖ ﮔﻮدی و ﺑﺮآﻣﺪﮔﯽ را از ﯾﮑﺪﯾﮕﺮ ﺗﻔﮑﯿﮏ ﻣﯽﮐﻨﺪ، ﺑﻪ ﺗﺮﺗﯿﺐ 4/2-> و 6 < ﻣﺤﺎﺳﺒﻪ ﺷﺪ. ﻣﻘﺎدﯾﺮ ﺷﺎﺧﺺ tri ﮐﻪ ﺑﻪ ﻧﻮﻋﯽ اﺧﺘﻼف ارﺗﻔﺎع ﯾﮏ ﭘﯿﮑﺴﻞ ﺑﺎ ﻫﺸﺖ ﭘﯿﮑﺴﻞ ﻣﺠﺎور ﺧﻮد ﻣﯽﺑﺎﺷﺪ از 0 ﺗﺎ 14 ﻣﺤﺎﺳﺒﻪ ﺷﺪ. و در ﻧﻬﺎﯾﺖ ﻣﻘﺎدﯾﺮ ﺷﺎﺧﺺ twi ﮐﻪ ﻧﺸﺎندﻫﻨﺪة وﺿﻌﯿﺖ رﻃﻮﺑﺖ ﺧﺎک ﻣﯽﺑﺎﺷﺪ ﺑﻪ ﺗﺮﺗﯿﺐ از 1/5-> ﺗﺎ 5/5< ﻣﺤﺎﺳﺒﻪ ﮔﺮدﯾﺪ. درﺻﺪ ﻣﺴﺎﺣﺖ ﻫﺮ ﯾﮏ از ﻣﻘﺎدﯾﺮ اﯾﻦ ﺷﺎﺧﺺﻫﺎ در ﺳﻄﺢ ﺣﻮﺿﻪ ﮐﻪ در ﻧﺘﺎﯾﺞ ﺣﺎﺻﻞ از اﯾﻦ ﺗﺤﻘﯿﻖ ﺑﺪﺳﺖ آﻣﺪ ﻣﯽﺗﻮاﻧﺪ در ﺑﺮﻧﺎﻣﻪرﯾﺰی ﻣﺨﺘﻠﻒ ﻣﺮﺑﻮط ﺑﻪ ﺣﻮﺿﻪ آﺑﺨﯿﺰ از ﺟﻤﻠﻪ ﻓﺮﺳﺎﯾﺶ و رﺳﻮب، ﻃﺒﻘﻪ ﺑﻨﺪی ﻟﻨﺪﻓﺮم ﻫﺎ، ﺷﻨﺎﺳﺎﯾﯽ و ﻣﻌﺮﻓﯽ ﻣﻨﺎﻃﻖ درﮔﯿﺮ ﺑﺎ ﺧﻄﺮ زﻣﯿﻦﻟﻐﺰش، ﻣﻄﺎﻟﻌﻪ ﺳﯿﻼب، ﺑﺮرﺳﯽ و ﻣﻄﺎﻟﻌﻪ ﻣﻨﺎﺑﻊ آب زﯾﺮزﻣﯿﻨﯽ و ... ﻣﻮرد اﺳﺘﻔﺎده ﻗﺮار ﮔﯿﺮد.

Investigation of Fermi characteristics of land surface based on morphometric indices and using GIS (Case study: Fahlian watershed)

Analysis of the Properties of the earth’s surface, which can be influenced by climatic, hydrological, intrinsic properties of formations and neotectonic activities, plays an important role in recognizing the physical Properties of the Watershed. On the other hand, understanding the physical Properties of the Watershed is one of the first steps required in morphological and hydrological studies. This research tries to study the shape of the earth’s surface in Fahliyan watershed using morphometric indices. For this purpose, 6 geomorphometric indices, total curvature, profile curvature, surface curvature, TRI index, TPI index and TWI index were selected and using the relationships for each index and using relevant extensions in ArcGis 10/3 software, each map These indicators were prepared. The results of calculating the total curvature show that more than half of the surface of the basin (52.80) has a concave curvature and 47.20 percent of it has convex curvature. Also, the lower and upper limits for curvature of the surface were 2.99 and 3.96 respectively and for the curvature of the profile were 4.87 and 4.2 respectively. Accordingly, the lower and upper limit of the TPI index, which divides the mode of nodule and bulge, was calculated as <4.2 and >, respectively. The values of the TRI index, which are somewhat different from the height of one pixel with their adjacent eight pixels, were calculated from 0 to >14. And finally TWI index values that indicate the soil moisture condition in the order of <1.5 to >5.5 calculated. The percentage of the area of each of these indicators in the Watershed, which was obtained in the results of this study, can be used in various watershed planning including erosion and sediment, Landform Classifcation, identifying and introducing areas involved with landslide hazard, flood studies, studying and studying resources Groundwater and ... to be used.