This investigation consists of the evaluation of the hidrological characteristics of the high basin of the Quiroz river from the volumes registered in the water gauge station of “Paraje Grande” and in the water gauge station of “Zamba” (km 0+817), considering the volumes registered in period 1954-1999 and precipitations in this zone in period 1972-1993. This analysis was made with the purpose of determining the availability of the hydric resource in the sub-river basins defined by the points of Vilcazán, Santa Rosa, Aranza, Chulucanitas and San Lazaro. To make an analysis in an ordered, faster and more precise form it has been developed a Geographic Informatic System of the zone and tools such as Arc Hydro of Arc GIS 9 have been used to delimit the river basins, to obtain their areas, as well as to make the analysis of Thiessen polygons. In addition, the hidrological data available in the “Paraje Grande” station, as well as the pluviometric data of all the high river basin of the Quiroz river were analyzed statistically. This allowed to consider, by means of a correlation between the volume in “Paraje Grande”, the areas and precipitation of the river basins defined by the proposed points, the water availability in these points.