Application of the SWAT model to evaluate the diffuse contamination sources at lake Chapala sub-basin, Mexico

The hydrological balance models of watersheds are tools to describe and predict the dynamic processes, through simulation, of the scenarios of the impact of productive activities in a region. In this study we determined the water balance and contaminant loading in Lake Chapala sub-basin by the soil and water assessment tool SWAT (2012). The model was configured with the digital elevation model, soil type data (including the results of laboratory analysis of each horizon) and land use was updated to 2010 using remote sensing data and the Explorafor software as well as climate databases EricIII-CONAGUA program. A decadal simulation was made (1999 to 2011) with the information of the analyzed variables in the area. The hydrological balance was negative by a margin of 300 %. This may be related to the exoreic condition of the sub-basin, as is the main flowing of the Lerma river. In terms of herbicide application it was predicted an average of 408 g/ha of active ingredient, with a degradation of 342 g/ha. For pesticides was obtained a value of 533 g/ha with a significant decline of 532 g/ha. The total of the dissolved herbicides and pesticides are of the order of 1.7 g/ha and 11 g/ha were adsorbed by the sediment.