Natural Hazards and Earth System Science www.nat-hazards-earth-syst-sci.net 1561-8633 1684-9981 8 6 2008 10.5194/nhess-8-1349-2008 http://www.nat-hazards-earth-syst-sci.net/8/1349/2008/ http://www.nat-hazards-earth-syst-sci.net/8/1349/2008/nhess-8-1349-2008.html http://www.nat-hazards-earth-syst-sci.net/8/1349/2008/nhess-8-1349-2008.pdf 1349 1357 2008-12-08 Runoff generation dynamics within a humid river basin S. Manfreda manfreda@unibas.it Dipartimento di Ingegneria e Fisica dell'Ambiente (DIFA), Università degli Studi della Basilicata, via dell'Ateneo Lucano, 10, Potenza, 85100, Italy The present paper introduces an analytical approach for the description of the soil water balance and runoff production within a schematic river basin. The model is based on a stochastic differential equation where the rainfall is interpreted as an additive noise in the soil water balance and is assumed uniform over the basin, the basin heterogeneity is characterized by a parabolic distribution of the soil water storage capacity and the runoff production occurs for saturation excess. The model allowed to derive the probability density function of the produced surface runoff highlighting the role played by climate and physical characteristics of a basin on runoff dynamics. Finally, the model have been tested over a humid basin of Southern Italy proposing also a strategy for the parameters estimation.