Monitoring of Temporal and Spatial Variation of Water Quality in Agricultural Reservoir During Summer

Abstract

This study investigated the spatiotemporal dynamics of water quality in a small-scale agricultural reservoir, the Bangok Reservoir, during the summer. The study is motivated by the increasing importance of preserving river ecosystems, ensuring irrigation water quality and expanding agricultural water use. Seven water quality parameters were monitored at multiple points from July to October 2020, and Spearman correlation analysis was conducted to understand their spatial relationships. The results revealed that the Bangok Reservoir had reached a hypertrophic state, indicating excessive nutrient levels. While heavy rainfall and dilution effects posed challenges for accurate analysis, significant correlations were observed between chlorophyll-a and total phosphorus, as well as between dissolved oxygen and pH. The trophic state index of Korea (TSIKO) indicated conditions favourable for algal growth due to phosphorus abundance. Higher concentrations of pollutants were found upstream, which was likely attributed to the inflow of livestock manure during rainfall and shallow water mixing. The study recommends the implementation of algae removal and reduction facilities in the upstream areas of the reservoir. These findings provide essential data for ongoing research on water quality in small-scale agricultural reservoirs and emphasize the importance of continuous monitoring for better environmental management.