The water is basic resource to the life, indispensable resource in the agriculture of familiar base, of average and wide it scales, and in almost all the productive processes. Suppliments of water demand are a continuous concern of the humanity, which had to the increasing population increase, the uncertainties of the climatic factors and the increasing hdrica pollution. In a devoid water region, the knowledge of the hidrolgicos processes is basic for the permanence and survival of the man in the field. With the increase of the population throughout the years, the gamma of uses of the water grew together with the relative restrictions to its quality. The uses of the water had evolved throughout the time, having involved the feeding and personal hygiene, agriculture, navigation, industrial production, cooling of thermoelectrial and nuclear plants and recreativas activities. The antrpicas actions have modified the climate in the most diverse regions of the world and many times the necessary conditions to maintenance of the life human being has been harmed. The awareness of the importance of the hdricos resources in the quality of life of the population comes originating increasing demands of information for the elaboration of projects, mainly in small hidrogrficas basins. The projects in these basins have attracted to the attention of researchers and borrowers of decision, since the data collected in these regions are valuable sources of information that could be used in bigger basins. The great variability of the hdrica availability, secular as in such a way space, standes out the necessity of permanent quantification of liquid discharges aiming at to the forecast of future outflows and the amounts of sediments produced for a rain event. The water availability in amount and quality for the diverse uses, in special the water for human supplying, is a concern of the humanity and the subject has been debated in diverse regions, mainly the half-barren ones.