Using SWAT to Simulate Streamflow in Trinity River Basin, Texas, USA

The uncertainties in the hydrology allied with the climate and land change have been a research topic of recent scientific and engineering communities. Texas Trinity River Basin (TRB) of an area about 46,620 square kilometres comprises the river system with maximum water storage as compared to the other river systems of Texas. TRB also includes hydraulic structures such as locks and dams, water control structures, and reservoirs while the watershed recently faced a flood. The current study will simulate the discharge in the Trinity River utilizing the soil and watershed assessment tool (SWAT) based on the basin characteristics like elevation, type of soil, land use, and hydrological variables like temperature and precipitation. SWAT is an arc geographic information system-based, semi-distributive physical model. The model was developed utilizing the basin properties like soil type, digital elevation model, land use, along with the meteorological inputs like precipitation, temperature, relative humidity, wind speed, and solar radiation adopted from climate forecast system reanalysis within TRB. The sensitivity and calibration of the model parameters were estimated using the sequential uncertainty fitting algorithm in SWAT calibration and uncertainty procedures-a powerful calibrating tool for SWAT models. The model was calibrated based on the observed streamflow from 1990 to 2009, and the model was validated with the observed streamflow of 2010 and 2013. Statistical evaluation indices and graphical presentation were used to analyze the robustness of the simulated results.