| Title |
A Modeling Study for an Assessment of Self-Purification Capacity in a Coastal Embayment |
| Authors |
박정은 ( Park Jeong Eun ) ; 박석순 ( Park Seog Sun ) |
| Keywords |
Water quality modeling; Flushing rate; Coastal embayment; Tidal movement; Self-purification capacity |
| Abstract |
This paper presents the results of modeling study to predict the flushing rate which is an indicator of self-purification capacity in a coastal embayment. They study was performed on the Mokpo harbor system and surrounded coastal area, utilizing the RMA-/RMA-4 models developed by U.S.Army Corps of Engineers. Two dimensional finite element grides(4,133 nodes and 1,296 elements) were constructed on the study area, based on the system geometry. Tidal flow and mass transport phenomena were simulated and validate against the measured tidal heights and water quality data. Model validation results showed reasonable agreements with the field measurements. Utilizing the validated models, tidal currents and water quality distribution were predicted spatially as well dynamically. The flushing rate was estimated from the water quality change within the embayment due to tidal movement. Two different flushing rates(with and without biochemical decay) were compared in order to examine the contribution of biochemical degradation to the self-purification. The flushing rate was computed at six locations during neap and spring tides. The results indicated that the flushing rates were significantly different by tidal pattern within the study area(neap and spring tides) as well as by locations. The biochemical degradation, however, does not cause a discernible impact on the flushing rate, indicating that tidal movement plays the major role in self-purificaton of pollution loads. From this study, it was concluded that the discharge location and time of pollution loads should be important parameters to be considered for the effective management of water quality in a coastal embayment. |