Evaluation of the Water Quality of Nakdong River Using the Real-time Water Quality Index

Recently, the influx of pollutants into rivers has increased owing to the impacts of climate and environmental change, consequently accelerating the pollution of river ecosystems and aquatic habitats. Consequently, river water quality must be precisely assessed to facilitate effective management strategies by discerning different aspects of water quality deterioration and enhancement and by identifying and regulating river contaminants. Understanding water quality at a cursory glance is highly challenging, particularly for individuals lacking expertise in water pollution assessment. Hence, the present investigation utilized a domestically developed real-time water quality index (RT-WQI) to scrutinize the water quality attributes at 12 specific locations within the total pollution quantity monitoring network situated in the main channel of the Nakdong River system to render the water quality of the river easily comprehensible even to non-specialists. Furthermore, an attempt was made to detect patterns by applying the Mann–Kendall test and locally weighted scatter plot smoothing (LOWESS) using the index values for water quality assessment. To achieve this aim, extensive water quality data (averaged on a monthly basis) spanning 2004–2022 were obtained from the Water Environment Information System of the Ministry of Environment (https://water.nier.go.kr). The gathered date were then subjected to computation of descriptive statistics for individual water quality parameters to delineate the distinctive features of water quality. This study anticipates that the evaluation of water quality across diverse river systems in the future will facilitate the identification of highly polluted rivers and confirm their trends, thereby providing fundamental data for the management of river basins and the formulation of water quality policies.