Modelación del efecto del cambio de uso del suelo en la cuenca del rio coello, bajo escenario de cambio climático, a través de la aplicación del modelo hidrológico swat (soil and water assessment tool)

Abstract

It is important to consider the current dynamics such as climate change and land use change, in order to evaluate the possible effects on water resources. In this context, the present research aims to determine and evaluate the effect of land use change under ideal conditions under a scenario of climate change in the Coello River basin, which is located in the department of Tolima in Colombia, through of the application of the SWAT (Soil and Water Assessment Tools) hydrological model. The watershed occupies 7.8% of the department and is important because it is a source of supply of different municipalities including the departmental capital, in addition it is the largest irrigation district in the country, where electricity is also generated. For the hydrological modeling, data from the periods 1988-2007 and 2011-2030 were used, the climatic data were calculated from general circulation models (GCM) and regional circulation models (RCM), in this case was used PRECIS model applying the HadCM3 model with the A1B scenario proposed by the Intergovernmental Panel on Climate Change (IPCC). The methodology for the recommended use map of Zúñiga 2010 was used for the land use change scenario, where the uses are determined according to the characteristics of the territory. The SWAT model was manually calibrated according to the observed monthly flow data for the period 1988 - 2007 in the Payandé station, obtaining goodness of fit of the model rated as very good (COE: 0.64, R2: 0.82). The SWAT model estimated the flows for the period 2011-2030 with and without land use change. For the scenario without land use change, a reduction of 3.45% of the average annual flow was obtained in comparison with the reference period (1988-2007), while for the scenario with land use change there was an increase of the average annual flow of 19.33%, compared to the reference period. It was also compared the estimation of the flow between the scenarios with and without land use change in the period 2011-2030, where the scenario with land use change presents an increase of 23.59% of the mean annual flow with respect to the scenario without land use change. The high degree of uncertainty in global circulation models should be taken into account in assessing potential future climate impacts to make decisions on actions to adapt to climate change in the area. However, this is a good starting point for planning and integrated management basin.