| Title |
Analysis of Organic Carbon Cycle and Mass Balance in Daecheong Reservoir using Three-dimensional Hydrodynamic and Water Quality Model |
| Authors |
안인경 ( Inkyung An ) ; 박형석 ( Hyungseok Park ) ; 정세웅 ( Sewoong Chung ) ; 류인구 ( Ingu Ryu ) ; 최정규 ( Jungkyu Choi ) ; 김지원 ( Jiwon Kim ) |
| DOI |
https://doi.org/10.15681/KSWE.2020.36.4.284 |
| Keywords |
Carbon cycle; Carbon fluxes; DOC; POC; TOC; Water quality modeling |
| Abstract |
Dam reservoirs play a particularly crucial role in processing the allochthonous and the autochthonous dissolved (DOC) and the particulate (POC) organic carbon and in the budget of global carbon cycle. However, the complex physical and biogeochemical processes make it difficult to capture the temporal and spatial dynamics of the DOC and the POC in reservoirs. The purpose of this study was to simulate the dynamics of the DOC and the POC in Daecheong Reservoir using the 3-D hydrodynamics and water quality model (AEM3D), and to quantify the mass balance through the source and sink fluxes analysis. The AEM3D model was calibrated using field data collected in 2017 and showed reasonable performance in the water temperature and the water quality simulations. The results showed that the allochthonous and autochthonous proportions of the annual total organic carbon (TOC) loads in the reservoir were 55.5% and 44.5%, respectively. In season, the allochthonous loading was the highest (72.7%) in summer, while in autumn, the autochthonous loading was the majority (77.1%) because of the basal metabolism of the phytoplankton. The amount of the DOC discharged to downstream of the dam was similar to the allochthonous load into the reservoir. However, the POC was removed by approximately 96.6% in the reservoir mainly by the sedimentation. The POC sedimentation flux was 36.21 g-C/m2/yr. In terms of space, the contribution rate of the autochthonous organic carbon loading was high in order of the riverine zone, the transitional zone, and the lacustrine zone. The results of the study provide important information on the TOC management in the watersheds with extensive stagnant water, such as dam reservoirs and weir pools. |