This paper presents a mathematical model of the structure outflow from the basin the concentrated parameters which is used to calculate outflow hydrograph from small catchments in the basin Krzyżówka. For each catchment fractional model identification stage set precipitation effective depends on the type of soil, land and adequate to reality linear model of surface runoff. Model parameters were estimated based on physiographic and geomorphological characteristics subcatchments. A mathematical model was used to determine the effect of various use the catchment area forms the culmination of the outflow hydrograph.