Funcionamento hidropedológico de uma topossequência e a produção de água em uma bacia hidrográfica de primeira ordem no oeste paranaense

Abstract

Hydropedological functioning of a toposequence and the water production in a first order watershed in the west of the Parana State Given the country's water richness and its significant use in the electricity production, understanding the interaction of the soil with different processes of the hydrological cycle at the watershed scale, brings important support for the adoption of actions aimed at conserving hydroelectric potential. Factors such as relief, soil types, use, management and conservation actions in the reservoir contribution basins, has an influence not only on siltation rates, but also on the regulation of the seasonal stability of the tributary flows, which is associated with rivers´s baseflow. Detailed information inherent to the soil hydro-physical and hydraulic functioning in situ, its relationship with the groundwater recharge and the hydrological responses of the watershed, in a hydropedological approach, are still scarce in Brazil, even for soils already widely studied as Oxisols occurring in the south center of the country. Thus, the present study aimed to understand the relationships between soil hydro-physical and hydraulic functioning, groundwater recharge and water production in a first-order watershed located on the left bank of the ITAIPU Binacional Hydroelectric Power Plant reservoir, from the hydropedological study of one of the topossequences of this basin and, from the observation of hydrological responses in the river channel. The soils were classified as Oxisols of the upper to lower third and as Inceptisols at the foot slope. For the soil hydro-physical and hydraulic characterization it was determined: bulk density, particle density, total porosity, soil water retention curves (0