| Title |
Temporal and Spatial Characteristics of Water Quality in a River-Reservoir (Paldang) |
| Authors |
공동수 ( Dongsoo Kong ) ; 민정기 ( Jeong-ki Min ) ; 변명섭 ( Myeongseop Byeon ) ; 박혜경 ( Hae Kyung Park ) ; 천세억 ( Se-uk Cheon ) |
| DOI |
https://doi.org/10.15681/KSWE.2018.34.5.470 |
| Keywords |
Eutrophication; Material Budget; Paldang; River-reservoir; Water quality |
| Abstract |
This study is to investigate the allochthonous load and water quality of a typical river-reservoir, Paldang during spring (March ~ May) of 17 years (2001 ~ 2017). Phosphorus loading from point sources seems to have been reduced by 74 % in the 2010s. As a result, trophic state of the Paldang reservoir, eutrophic during the 2000s, has returned to the lmesotrophic state. Along with decrease in phosphorus concentration, standing crops of algae (Chl.a) decreased, and concentration of biodegradable organic material decreased to the past level. Concentration of total suspended solids has decreased, and it is due to the decrease of phytoplankton standing crops since the mid-2000s. As transparency increased, it is estimated that euphotic area increased by 22 % and euphotic capacity expanded by 27 %. In the river/transition zone of Paldang, concentration of organic matter increases slightly due to algal growth, but concentration of all water quality items decreases in the lacustrine zone. Although algal growth rate revealed positive correlation with concentration of phosphorus, it was insignificant. Algal growth appeared to be dependent on renewal of phosphorus by flow, than either flow rate or phosphorus concentration. The empirical model including inflow phytoplankton concentration fit well with observed values, and indicates the Paldang reservoir is greatly influenced by allochthonous loads. |