The main objective of this research is to find landscape structure of watershed by using the method of hydrological simulations. A watershed is a basic physical entity of the landscape and most processes related to the movement and/or quality of the water occur in the catchment or sub-catchment areas of the watershed. The basic tool used to analyze the landscape of a watershed is Digital Elevation Model (DEM) in order to obtain the Drainage Direction Matrix (DDM) by which is possible to obtain stream network structure. One of the relevant applications of the DDM is to identify possible sources of water pollution by isolating and tracking back the pollutants inside a river network. The main contribution of this study is to present a high resolution stream network in Haji Dam watershed using 10m DEM. By calculating Horton ratios (Rb = 4.45, Rl = 1.93) and fractal dimensional parameters (d = 1, D = 1.97) it is been demonstrated the importance of a high resolution DDM for the precise comprehension of the watershed system and the correct interpretation of it relief, topography and complexity.