The method of calculation of daily runoff coefficients based on the SCS USDA curve number method is presented in this paper. The calculated values of daily runoff coefficients for climatic and geological conditions of the city of Lviv for maximum daily rainfall events with a return period of 0.1 – 5 years are obtained.
It was analyzed Ukrainian normative documents, regulating the procedure of calculating the average annual volume of stormwater runoff from urbanized areas. It was found the big differences as in the numerical values of the general (annual) runoff coefficient, so in the classification of the surface cover type. Methods 1 and 2 indicate the ranges of numerical values of the general runoff coefficient for different cover types, but don’t explain the criteria for selecting the precise values for performing calculations under certain conditions.