بررسی آستانه توپوگرافی در روستای جهان آباد قزوین

Gully erosion is one of the most important types of erosion in terms of sediment production. In the supplementary visit, a total of 34 Gullies were selected and their location was recorded with the global positioning system. UAV imaging was used to prepare a digital elevation model map of the gully watershed. The morphology of the watershed of each gully watershed (border, perimeter, area, slope, roundness factor and shape factor) was done. The topographical threshold of waterholes was determined according to the equation of Poesen et al. (2003). Coefficients a and b were calculated by determining the regression relationship between slope and area in each area using Excel software. The soil of Jahanabad region has an average EC of 11 ds/m, SAR of 21, and pH of 8.7, which indicated medium salinity and alkalinity conditions. The general equation of the topographic threshold showed a downward exponential relationship and the relationship is negative, which, like other surface runoff areas, was an effective factor in the creation of watersheds. The aspect and coefficient of the area-slope relationship in the state of expansion showed that although the aspect of the relationship is low, it has become positive and indicates the role of subsurface runoff as an effective factor in the expansion of the floodplain. Drawing the relationship in this area for the creation mode caused a decrease and in the expansion mode, it caused an increase in the explanation coefficient of topographic threshold relations.