Streamflow modeling of five major rivers that flow into the Gulf of Mexico using SWAT

It has been shown that detailed and continuous riverine discharge and nutrient input data are fundamental to the successful simulation of biogeochemical processes in the ocean using numerical models. Currently, no discharge data for the river mouths on the Mexican side of the Gulf of Mexico (GoM) is available. In the present study, the Soil and Water Assessment Tool (SWAT) was used to simulate the daily discharge of five major rivers that flow directly into the GoM. Two periods were used in the analysis: 1997 to 2013 for the Grijalva basin and 1989 to 2013 for the Usumacinta, Papaloapan, Coatzacoalcos, and Panuco basins. The model was successfully calibrated for monthly time steps using an automatized technique for the five watersheds. The sensitivity analysis of the calibration process showed that for most of the watersheds, the model was sensitive to groundwater and soil moisture parametrization.