A Study on Identifying Priority Management Areas and Implementing Best Management Practice for Effective Management of Nonpoint Source Pollution in a Rural Watershed, Korea

Abstract

It is difficult to accurately identify and manage the paths of nonpoint source (NPS) pollution in rural watersheds because their discharge patterns vary depending on season, region, and agricultural characteristics. In this study, flow and water quality during rainfall events were monitored in Songya watershed, an impaired, rural area in South Korea. A method of identifying priority management areas was proposed through scientific objectification and quantification of key factors controlling NPS, such as land use, agricultural type, and load. For the load calculation, a watershed model was developed using Hydrological Simulation Program Fortran (HSPF). Three priority management areas—Mulhan Stream, Osan Stream, and the upstream area of Songya Stream—were selected. Using the developed model, constructed wetlands with the capacity of 1000 m3 were applied at the lower reach of each priority management subbasin and the impacts on NPS pollution reduction were tested. The simulated results showed that BOD and TP concentrations at the outlet of Songya watershed were lowered by 9.2% and 6.0%, respectively. It is expected that the method proposed in this study for identifying priority management areas and implementing best management practice in agricultural watersheds can be applied to similar areas which struggled with NPS pollution.

The Impact of Non-Point Source (NPS) Management on Non-Point Source Reduction and Water Cycle Improvement in an Urban Area

“…The city was designated as an area that requires non-point source management in 2009, and has a population of approximately 1.1 million. The non-point source management area designation system, which has been implemented since 2007, is a policy to designate and manage areas where the rainfall runoff caused by non-point sources has caused or is likely to cause serious hazards to rivers, lakes, humans, or natural ecosystems [13][14][15]. One out of four cities was designated when the system was first introduced, but 8 (approximately 31%) out of 23 areas were designated as urban areas with a high impervious area ratio and managed for non-point sources in 2023.…”