Comparison of the Most Important Factors in Runoff Production for the Slope Main Aspects in Gachsaran and Aghajari Formations

Investigating the spatial variability of runoff and its influencing factors to provide solutions to reduce it is very important. In recent years, many theoretical and field studies have evaluated the spatial production of runoff as heterogeneous.

In this study, to investigate the affecting factors in runoff production of the slope main aspects (northern, southern, eastern, and western) of the Gachsaran and Aghajari formations were selected a part of the Gach Kuhe and Margha watershed in Izeh city. For this purpose, a rain simulator was used in both formations at 16 points with 3 replications at rainfall intensities in 1 and 1.25 mm/min. Also, soil factors of Gachsaran and Aghajari formations such as percentages of gravel, sand, silt and clay, pH, soil salinity, moisture, calcium carbonate, organic matter, and sodium content were investigated. SPSS 17 and EXCEL 2007 software were used for statistical analysis.

The most important factors affecting runoff production were identified using multivariate regression. The results showed that runoff production in Aghajari Formation is more dependent on soil chemical properties, but runoff production in Gachsaran Formation is more dependent on soil physical properties.