Experimental and model investigations of vegetative filter strips for contaminant removal: A review

This work provides a comprehensive review on the specific transport characteristics and the associated transport models of sediments, chemicals, and colloids in vegetative filter strips (VFSs). The main goal of the review is to improve current understanding of the main processes, mechanisms, and models of VFSs as the best management practice to mitigate the non-point source pollution. The overall removal efficiency of a VFS varies among different contaminants. For sediments, particle size and distribution are the critical factors that influence their fate and transport in VFSs. For adsorptive chemicals such as pesticides and phosphorus (P), one critical factor for their fate and transport in a VFS is the distribution coefficient between soluble and particle phases. For nonreactive chemicals such as nitrogen (N), soluble phase plays an important role in controlling their fate and transport in a VFS, while bio-chemical reaction may also be important. For colloids, particle and flow characteristics are the main factors affecting their transport and removal in a VFS. Previous studies have built transport models based on the specific characteristic of contaminants. Some of the models are empirical with regression equations based on experimental data. There are also some mechanistic VFS models that are process-based and rely on contaminant transport mechanisms. When coupled with the hydrology models, these models can be used to simulate the fate and transport of various contaminants in VFSs.