This diploma thesis deals with lateral flow of water, which was measured and subsequently evaluated by electrical resistivity tomography (ERT). Electric resistivity tomography represents an ideal method for monitoring soil properties. By providing a non-destructive measurement method, it offers opportunities to observe an undisturbed environment, and with the ability to repeat measurements on a single transect, it provides the ability to track time changes in the soil. At work we had observed the movement of soil water and its lateral flow in sloping terrain and the impact of environmental disturbance on the development and transformation of subsurface flow to surface. In our research the disturbance of the soil environment in the sloping terrain was represented by notches of forest roads. By disrupting the soil environment, the subsurface watercourse is transformed into surface outfall. This state causes a loss of water in the water balance of the forest ecosystem and oftentimes it causes damage not only in the forest economics, but also to property of private people. Because of disturbed environment, caused by water movement, we performed measurements of electric resistivity tomography by 2D multicable method on three parallel profiles, which were subsequently connected into 3D image and evaluated by time series method. The results of the work show that after the precipitation in a shallow layers of the soil the infiltrating water moves along the slope and transforms into a surface outfall at the point of disruption. The transformation of the stream is dependent on the pedological characteristics of the area and can occur at relatively short distances.