This paper shows a preliminary quantitative analysis of the hydrological basin of Grande river (Málaga) using a Geography Information System (GIS). The analysis takes into account a description of the natural conditions and mainly spatial and form variables which are used to characterize the stream network and fluvial morphometry. A critical analysis of the results obtained in this work demonstrates that floods of Grande River represent a natural hazard basin because of its physical characteristics (i.e. form, altitude, slope and stream network) and the lithologies (the permeable carbonate rocl<s outcrop only in the high part)