BACKGROUND: Wicheon watershed has the largest irrigation area among the mid-watershed of Nakdong river. However, no investigation of irrigation water quality has been conducted on the Wichon watershed, which assesses the impact on the soil quality and crop cultivation. Therefore, this study aims to provide various assessments of water quality of Wicheon watershed as the scientific basic data for efficient agricultural activities.
METHODS AND RESULTS: Sampling sites were selected for five locations in Wicheon and five locations in the first tributaries of Wicheon. Wicheon watershed showed clean water quality with very low organic matters and safe water quality from metals at all points of investigation. It was estimated that the natural chemical components of Wicheon watershed were originated from water-rock interaction in Gibbs diagram. All samples were concentrated in the type of Ca-HCO3-Cl in the Piper diagram. The quality of irrigation water was evaluated with sodium adsorption ratio (SAR), residual sodium carbonate (RSC), permeability index (PI) and percent sodium (%Na). The values of these water quality indices were in the range of 0.3―0.7, -0.18―-2.42, 39―87% and 11.1―22.1%, respectively, and were classified as good grades at all sites.
CONCLUSION: The water quality of Wichon watershed was very low in salt, indicating irrigation water suitable for growing agricultural products. We hope that the results of this study will be used as the basic data for the cultivation of agricultural products and promotion of their excellence.