Hydrological Modeling in a watershed of the Lower Araguaia River Basin, TO

Hydrological simulation is an important tool for water resources management since it allows for practitioners toevaluate the impacts of anthropic activities and climatic changes on water availability. The Lontra River watershedis situated in the Lower Araguaia River Basin which is an important economic region of Northern Tocantins State.The understanding of its hydrological features is fundamental for the development of environmental studies forsupporting the decision-making related to the water resources management as strong pressure has been observeddue to both the agricultural frontier expansion and installed economic center. The LASH hydrological model (standsfor Lavras Simulation of Hydrology) is characterized as a deterministic, semi conceptual and spatially distributedmodel and has been successfully applied in watersheds located in Southeastern Brazil. It was found in this study thatthe model was able to adequately capture the overall hydrological regime in the studied watershed. Three statisticalcoefficients used for measuring the model goodness-of-fit, Nash-Sutcliffe (CNS), Log (CNS) and determinationcoefficient (R2), have shown values greater than 0.74, 0.80 and 0.90, respectively. The simulated flow duration curvepresented a good fit in relation to the observed one, with small errors for prediction of minimum and maximumstream flows. Thus, we can be conclude that LASH model simulated properly the hydrological regime in the LontraRiver Watershed and it can be applied for either evaluation water availability or planning and management ofwater resources in the Lower Araguaia River Basin.