Perceived change in climate over the world begins to be negatively felt in our geographical latitudes, too. Increasing global surface temperature, extreme temperature differences in a short period cause so far unprecedented progress of the weather: dry periods with deficient rainfall are followed by periods of excessive rainfall that is impossible to be absorbed and accumulated by the surface, which causes hydrological cycle disruption in nature. More and more often there occur such rainfalls: in small river basins enormous amount of water fall to the ground and runs down unrestrainedly over surface into watercourses causing so-called flash floods with inconceivable material and moral consequences.