Trapping efficiency with rainfall and seasonal changes in vegetative filter strips over a course of three years

Nonpoint source pollution does not have a clear route for elimination, and due to the amounts of these types of pollution, it is not easy to eliminate the polluting substances. In addition, the characteristics of nonpoint source pollution can easily be affected by factors other than the concentration, making it difficult to predict the pollution sources. Therefore, we installed a vegetative filter strip, which is a natural type of nonpoint source, around Kyung-An stream and calculated the trapping efficiency occurring during rainfalls, after which we analyzed these results. Over a period of 3 y, we monitored these strips 17 times, dividing the events by growth periods and non-growth periods to look more carefully into their effectiveness according to the rainfall levels. Owing to the special characteristics of nonpoint source pollution, the range of data was wider, but as we went through the elimination process, the number of outflows appeared to be more stable than the number of inflows. During the growth period, the efficiency appeared to be higher than it was in the non-growth period, but the range of data appeared wider. Regarding the rainfall levels, the trapping efficiency showed maximum efficiency at less than 10 mm of rainfall.