Simulação hidrológica na bacia hidrográfica do rio Muaguide utilizando o modelo SWAT - Soil and Water Assessment Tool

Abstract

The hydrological simulation arises from the need to understand the phenomena of the hydrological cycle, enabling the estimation of water availability as well as the impact of physiographic and climatic changes in hydrographic basins resulting from natural processes or triggered by human intervention. The watershed of the Muaguide River includes the territories of the districts of Pemba and Ancuabe and is of great importance for the city of Pemba. Population growth and economic development that occur in these regions provide an increasing exploitation of available water reserves, leading to the need to estimate water availability. However, the poor monitoring of the Muaguide river basin constitutes a barrier to this estimate. In this context, the objective of the study focused on the hydrological simulation in the watershed of the Muaguide River using the SWAT model aiming at the estimation of surface and underground flows. The input data for the model were EROS land use and occupation, FAO soil type, digital elevation of the SRTM 90 terrain and data from CFRS meteorological stations, which allowed the subdivision of the watershed into drainage subareas and units of hydrological response as well as hydrological simulation. For the calibration and validation of the model, data referring to surface runoff from hydrometric stations E-423 and E-199, respectively, were used and the evaluation was performed using objective functions, namely, coefficient of determination (R2), standard error (RSR ), Nash-Sutcliffe coefficient (NS) and Mass balance error (PBIAS). The data from the hydrometric station E-423 cover the period between 1982 to 1985 while the data from the hydrometric station E-199 cover the period between the years 1982 to 1987. The values ​​of the objective functions obtained in the calibration and validation process are within acceptable ranges, therefore, the simulation is considered satisfactory. With a validated SWAT model, direct runoff, base runoff and total recharge were simulated, whose volumes in mm per unit area along the watershed range from 31 to 78, 0 to 67 and 0 to 604, respectively (TRADUÇÃO NOSSA).