A land use map was issued by photo interpretation of aerial photographs, and it showed the following classes: bare rocks, rangeland, natural forest, forest plantation, dry cultivation, irrigated crops and rivers. The soil type was derived from the combination of both the geological map and the land use, including the following seven classes: bare rocks, magmatic rocks, downslope colluviums (on magmatic substratum), clay material, clay loam material, basalt and rivers (Fig. 3).