Development of the Integrated SWAT-VFSMOD model

Abstract

Because of negative impacts of sediment-laden water by accelerated soil erosion and transport processes, many researchers have been investigating to develop most effective soil erosion management practices. Hydraulic structures such as soil erosion control dams and grit chamber are installed widely. Instead of structural best management practices, non-structural best management practices, such as the Vegetative Filter Strip (VFS) has been thought as one of effective methods with less effort. The VFS is designed for reducing sediment from upland areas such as cultivated area. In addition, it has many positive functions by providing wildlife habitat. For these reasons, various researches regarding the VFS effects have been increasing in many countries. For maximum effects of the VFS on water quality improvement, the sediment trapping efficiency by VFS needs to be investigated and designed before its installation at the fields. For this purpose, the desktop-version of the VFSMOD system can used to estimate sediment trapping efficiency of vegetative filter strip under various field and vegetation conditions. However, the VFS effects at the receiving water body cannot be simulated with independent VFSMOD and SWAT system. In the current SWAT model, the VFS is simulated with simple regression equation, which is a function of VFS width solely. Thus the VFSMOD system was integrated with the SWAT model to simulate the VFS dynamically with several sensitive factors affecting the VFS performance, such as CN, soil type, rainfall, and other various factors, instead of evaluating its performance with VFS width only as in the current SWAT system. With the integrated SWAT-VFSMOD system, SWAT simulated output data are used as input to the VFSMOD dynamically and its effects are simulated with existing SWAT routing component. It was found that the SWAT-VFSMOD system can be efficiently used to simulate VFS effects on water quality improvement.