Estimation and zonation of soil erosion in Mamlou watershed (Eastern Tehran) with RUSLE and AHP methods

Soil erosion is a very essential problem in most countries, particularly in developing countries with arid and semi-arid climate. Soil loss, decrease of agricultural lands and products, dam's fillings, destruction of jungles, pastures and rural migration are all results of soil erosion. In this study, using AHP and RUSLE methods, rate and amount of soil erosion in Mamlou watershed (eastern Tehran) have been estimated. By means of, using satellite images and maps and applying effective factors including DEM, slope, precipitation, land cover, lithology and NDVI,. The final map of estimation of soil erosion is subdivided into five erosion groups; namly very high, high, mid, low and very low. The results showed that about 13% of the basin surface has high and very high erosion. The average amount of soil erosion in the basin surface is about 10.7 ton-/hectare per year. In some western and southern subbasins, the amount of soil erosion is up to 80 tons. These subbasins show critical and crucial conditions and in connection with the construction of Mamlou dam priority should be giving to executing watershed management and soil conservation plans. The results also showed that, AHP method together with GIS is a powerful means for estimation, representation and zoning of soil erosion rate. Nevertheless, some more quantitative and new models can be used for attaining this goal.