영산강수계 농업용 저수지의 수질 특성

In order to study the characteristics of water quality, a total of 20 reservoirs located at upstream of the major stream in Yeongsan River basin were selected for measurement, and we conducted field surveys and water quality analysis twice. As a result of water quality analysis, 14 out of 20 reservoirs did not meet water quality standard for the agricultural reservoir because one or more items showed water quality grade of ‘bad (V)’ due to exceeding the standard according to the Ministry of Environment''s Reservoir Water Quality Standard. In addition, as a result of the eutrophication evaluation using the Korean trophic state index, 17 of the 20 reservoirs were found to be ''eutrophic'' state. According to correlation analysis between water quality observation items, chemical oxygen demand (COD) was highly correlated with total organic carbon(TOC), Chl-a, and T-N(r=0.82, r=0.78, r=0.53). However, there was no correlation between Chl-a and T-P. In the second survey also, eutrophication was continuously found in 85 % of the reservoirs. Compared to the first survey period, TSIko(T-P) value increased from 100.3 % to 292.1 % in 17 reservoirs during the second survey. This is attributed to the increase in the phosphate concentration introduced from external source. Therefore, it is necessary to identify the cause and prepare countermeasures through long-term monitoring of the inflow of external pollutants and the water quality of the reservoir.