Selection of priority watershed for water environment management

Abstract

As part of the National Water Management Basic Plan, this study conducted research to identify priority management watersheds in the Yeongsan River basin to respond to changes in water environmental conditions and improve water quality. Analysis of water quality over the past decade revealed that points located in the middle and lower of the Yeongsan River exceeded the target water quality standards. As based on the results, pollution sources and loads indicated that the W-1 watershed, classified as urban areas, exhibited high levels in residential, industrial, and urban landuse characteristics, whereas the W-6 watershed, classified as rural areas, showed high levels in livestock farming, aquaculture, and agricultural landuse (wet and dry filed) categories. To understand the impact of point source (PS) and non-point source (NPS) pollution within the watershed, load duration curve (LDC) analysis was conducted, indicating that downstream segments of all flow ranges exceeded the target water quality standards, necessitating management of both PS and NPS. Multivariate log-linear analysis also confirmed the influence of PS and NPS, suggesting that watershed management should concurrently address both types of pollution. Based on the results, priority management watershed rankings were derived through the calculation of standard and integrated indicators, with the analysis indicating the following order: W-1 > W-6 > W-3 > W-4 > W-2 > W-5 > W-7 > W-8. PRACTITIONER POINTS: Priority management watersheds that urgently need water environment management can be identified. The priority management watershed rankings were derived through the calculation of integrated indicators data on BOD, TP concentration, and loads. Serve as a guide for future diagnostic assessments of pollution sources and the development of effective management strategies. Anticipated to significantly contribute to the establishment of robust water quality management practices in the basin.

Keywords: NPS; priority management; water environment; water quality; watershed.