EFFECT OF LIVESTOCK AND AGRICULTURAL NPS POLLUTION ON THE WATER QUALITY OF A SMALL WATERSHED

摘要

The agricultural area among Korean land area is 25% of the total land area of the country, andit is estimated that non-point pollution generated in agricultural areas contributes to more than20% of the total water quality pollution. In addition, there is pollution arising from the illegaldisposal of domestic waste water, domestic sewage, and livestock excretion from the agroindustrialcomplexes and livestock facilities. Livestock excretion among them is far higherin pollutant loads than other waste waters. According to the Korea Ministry of Environment,untreated drainage effl uent from livestock farmhouses, with 7 to 28 times higher pollutantconcentration, as compared to the water quality of other effl uent water, fl ow into streams.Recently, the number of livestock-raising houses of domestic livestock industry has decreasedconsistently; on the other hand, due to the increase of livestock numbers, the generationquantity of livestock excretion is increasing simultaneously and environmental pollution bylivestock excretion is on the rise. But, the investigation on the pollutant characteristics andits quantifi cation are not done. The study reported in this paper has quantifi ed non-pointpollution substances by monitoring them in the forests, stockbreeding, and farmland and triedto comparatively analyze runoff characteristics of two pollutants, targeting a small watershedhaving both individual and public excretion disposal facilities. The target watershed of thisstudy is the whole area of Dumil-ri, Gapyeong-gun in Gyeonggi-province. In here, Dumilstream and Daljeon stream join and fl ow downstream, and livestock numbers of more than6,300 and composting facilities in the watershed are included.