Investigation of Shape Properties of earth's surface Based on Morphometric indices Using GIS(Case Study: Fahliyan Basisn)

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.