Effects of multifunctional weir construction on key water quality indicators: a case study in Nakdong River, Korea

Abstract In this study, changes in water quality characteristics were compared before and after the construction of eight multifunctional weirs Nakdong River Basin South Korea. A cluster analysis spatial variation showed that locations classified as Cluster 1 pre-construction (sites ND7 ND8) shifted into 2 post-construction, indicating types changed weirs. Principal component factor analyses revealed nitrogen phosphorous nutrients at stage (total nitrogen, total phosphorous, phosphate-phosphorus) electrical conductivity extracted principal 1, while biochemical oxygen demand, chemical pH, chlorophyll-a 2. However, organic carbon, post-construction nitrate-nitrogen, dissolved The key indicators transitioned from to pollutants trend with seasonal Mann–Kendall testing locally weighted scatter plot smoothing methods pollutant such demand carbon tended increase Therefore, for improvement management should be carbon.