Modelling of vegetative filter strips in catchment scale erosion control

Authors

• K. RANKINEN
• S. TATTARI
• S. REKOLAINEN

DOI: https://doi.org/10.23986/afsci.5684

Abstract

The efficiency of vegetative filter strips to reduce erosion was assessed by simulation modelling in two catchments located in different parts of Finland. The areas of high erosion risk were identified by a Geographical Information System (GIS) combining digital spatial data of soil type, land use and field slopes. The efficiency of vegetative filter strips (VFS) was assessed by the ICECREAM model, a derivative of the CREAMS model which has been modified and adapted for Finnish conditions. The simulation runs were performed without the filter strips and with strips of 1 m, 3 m and 15 m width. Four soil types and two crops (spring barley, winter wheat) were studied. The model assessments for fields without VFS showed that the amount of erosion is clearly dominated by slope gradient. The soil texture had a greater impact on erosion than the crop. The impact of the VFS on erosion reduction was highly variable. These model results were scaled up by combining them to the digital spatial data. The simulated efficiency of the VFS in erosion control in the whole catchment varied from 50 to 89%. A GIS-based erosion risk map of the other study catchment and an identification carried out by manual study using topographical paper maps were evaluated and validated by ground truthing. Both methods were able to identify major erosion risk areas, i.e areas where VFS are particularly necessary. A combination of the GIS and the field method gives the best outcome.