Improvement of the estimation method for non-point source pollution load reduction in Korean total maximum daily load management system

This study focused on improving the regression equations for the cumulative rainfall ratio (CRR), cumulative pollutant load ratio (CPR), and average pollutant load reduction efficiency of non-point source (NPS) pollution load reduction facilities to facilitate the calculation of NPS pollution load cutback used in South Korea's technical guidelines for the total maximum daily load. The recently updated hourly rainfall data from the Korea Meteorological Administration and NPS pollution load monitoring data from the Ministry of Environment (MOE) were used. Furthermore, the updated rainfall patterns and data together with the existing regression equation were used to formulate an improved regression equation for the CRR, which was used to calculate the CRR. Additionally, the improved regression equation for the CPR was used to determine the area type weighted CRR based on (i) CRR of land cover and (ii) public data provided by the MOE for 2008-2014. Also, the pollutant load reduction efficiency of the NPS pollution reduction facilities was updated using data of the inflow and outflow monitoring of NPS pollution reduction facilities obtained from various pilot projects or research on NPS pollution load by the MOE and by adding efficiency data of previously excluded low impact development techniques.

Automated summary

This study aimed to improve the regression equations for the calculation of non-point source pollution load reduction in South Korea, focusing on cumulative rainfall ratio, cumulative pollutant load ratio, and pollutant load reduction efficiency. The study utilized updated rainfall data and pollution load monitoring data, as well as inflow and outflow monitoring data from pilot projects and research. The updated regression equations were formulated to enhance the accuracy of the NPS pollution load reduction calculation.