A Simple Hydrologic Model for Water Resources Simulation on Rio Grande Basin, Minas Gerais State, Brazil

摘要

Physically based hydrologic models for watershed are important tools to support water resources management and predict hydrologic impacts produced by land-use change. Rio Grande Basin is located in south of Minas Gerais State, and the Rio Grande is the main tributary of basin which has 2080 km~2 draining into the Camargos Hydropower Plant Reservoir (CEMIG). The objectives of this work were: 1) to create a semi-physically based hydrologic model, in lumped andsemi-distributed to sub-basins approaches and based on GIS and Remote Sensing tools and, 2) to simulate the hydrologic responses of the Rio Grande basin, thus creating an important tool for management and planning of water resources for region. The hydrologic model is based on the SCS Curve Number (SCS-CN) as modified by Mishra et al. (2006) and MGB/IPH models, and structured into three hydrologic components: estimation of the flow components (quick runoff, hortonian and base flows), propagation into the respective soil reservoirs (surface, sub-surface and shallow saturated zone) and propagation into channels. Precipitation and discharge data sets were obtained from the Brazilian National Water Agency (ANA), summing, 10 pluviometric stations and 2 gauging stations in the basin. Reference evapotranspiration (ETo) data were obtained from the Brazilian National Meteorological Institute (IN MET) for just one location. In order to estimate actual evapotranspiration, crop coefficient, soil moisture and satellite image interpretation were applied. Long-term hydrologic series were structured for period between 1990 and 2003. Model calibration phase was carried out applying data set of 1990 - 2000, using the Nash-Sutcliffe Statistical Coefficient (C_(NS)) toevaluate the model performance. A validation period (split simple test) was carried out applying the calibrated model to the period of 2001 - 2003. In addition, some hydrologic variables were estimated by extracting from simulated hydrographs, which werecompared to observed values. The statistical precision showed that the model was able to simulate the hydrologic impacts produced by land-use change on Rio Grande Basin, with C_(NAS)H greater than 0.7 for both calibration and validation phases.