Effect of surface area to catchment area ratio on pollutant removal efficiency in vegetation-type facilities

In Korea, non-point source emissions have been investigated since the early 1980s, and the proportion of non-point source sources as a source unit for each land use has been evaluated based on actual measurement data following the implementation of the Total Water Pollution Control System. Recently, a lot of research has been done on the application of LID(low impact development) technology that can effectively manage nonpoint pollution and rainfall runoff. The ratio SA/CA (surface area/catchment area) is one of the design factors for LID facilities. In this study, the major objective is to analyse relationship between the SA/CA ratio and efficiencies of runoff reduction and pollutant removal. To do this, long-term monitoring has been conducted for three - years at LID facilities installed at a domestic LID pilot project complex. The type of LID facilities analyzed in this study are grassed swale, vegetative filter strip, tree filter box, planter box, and bioretention. As a result of logarithmic relation analysis, efficiencies of pollutants removal tended to increase with increasing SA/CA ratio. Among the pollutants, TP(total phosphorus) had the highest correlation with R value of 0.9365. When SA/CA is under consideration as a design factor, this research data can be used as input for the designer for calculating the specific criteria and scope.