Ji- Sung Lim, Jae-Ho Lee, Young-Woo Kim, Sang-Hoon Lee, Hyang-Gi Kim, Tae-Joo Park and Im-Gyu Byun
Civil and Environmental Engineering, Pusan National University, South Korea
Nakdong River is one of the major rivers in South Korea. Mulgeum site, which is downstream of Nakdong River, is the intake station of Busan metropolitan city. This study examined the chlorophyll-a(chl-a) concentration as a representative parameter of the occurrence of algae at the Mulgeum site from 1998 to 2014. The water quality, hydraulics and climate conditions were used to determine the parameters significantly affecting the chl-a concentration. The correlations between chl-a and the other parameters were analyzed by the Pearson coefficient. As a result, the chl-a concentration showed clear patterns according to the seasonal changes. High chl-a concentrations by Stephanodiscus spp., which is the dominant species in low water temperature at Mulgeum site, were observed in winter. On the other hand, low chla concentrations were observed in summer. The Monsoon climate characteristics have a significant effect in summer. Correlation analysis also showed different significant parameters to seasonal changes. In winter, pH, DO, BOD, COD, and PO4-P showed a significant correlation with the chl-a concentration.
Keywords: Nakdong River, Algae, Correlation, Water quality, Hydraulics, Climate, Dominant species, Seasonal change.