Precipitation structure as an indicator of reduction of water amount supplying soil profile

Abstract The objective of this study was the estimation of the effect of droplet structure of diurnal precipitation totals, measured with Thies Clima disdrometer, on the value of surface runoff from three kinds of surface used in urban areas, i.e. a roof surface covered with small-grain roofing paper, a car park surface of openwork concrete slabs, and a tarmac surface, and the resultant reduction of infiltration from atmospheric precipitation. The detailed comparative analysis of diurnal precipitation totals in the aspect of droplet structure, structure of increasing influx of precipitation water to the surface, and changes of air temperature-humidity conditions, allowed preliminary elucidation of the effect of those factors on the values of the runoff indices for the different hardened surfaces. The analysis of reduction of infiltration presents the level of supply losses resulting from the use of surface covering systems with various degrees of permeability to precipitation water. A solution that can minimise the indicated losses can be an approach to precipitation water management assuming interception of possibly the largest amounts of non-productive surface runoff waters, and then using that water.