하천유출수를 고려한 협수로 연결 폐쇄성 내만의 해수순환 특성

Abstract

With the Noryang waterway as the center, the Gwangyang bay, the Yeosu strait are located in the west side, the Jinju bay, the Gangjin bay and the Sacheon bay are located in the east. The outflow water from several rivers located in the study area flows into the each bay, especially in the event of flooding, that of the Seomjingang flows into the Gwangyang bay area(including the Yeosu strait) and that of the Gahwacheon(discharge of Namgangdam) flows into the Jinju bay area(including the Gangjin bay and the Sacheon bay) in large quantities. The Gwangyang and the Jinju bay area are connected by a waterway called the Noryang waterway, and the outflow water of the Seomjingang and the Gahwacheon also affects each other through the Noryang waterway. In this study, the characteristics of the variation of seawater circulation in water around the Noryang waterway due to the outflow water of 51 rivers, including the Seomjingang and the Gahwacheon located in the study area, were to be identified through seawater flow, particle tracking, freshwater diffusion experiments. In addition, through the experiment for extreme situations in which is the Noryang waterway closed, this study reviewed about the role and value of the Noryang waterway in the sea water circulation of the Gwangyang bay and the Jinju bay. As a result, in the flood the flood tidal current is weakened due to strong southerly currents caused by river outflow water, showed a change in the ebb tidal current that became stronger, and unlike the fact that the river outflow water of Seomjingang affects the Jinju bay area to some extent, the effect of the river outflow water of Gahwacheon on the Gwangyang bay area was minimal. Tidal wave entered the Noryang waterway before the Jinju bay, as a result, in the flood tide time, the water flowing into the Noryang waterway and that flowing into the Daebang waterway joins on the middle of the Jinju bay to move southward to the Gangjin bay, and in the ebb tide time, was an opposite flow. Calculation of the cross section water flux over 30 days for 7 internal areas and 5 external areas, the main essential flow direction of the water flux was found to the river outflow water from the Seomjingang flow through the Yeosu strait to the outer sea, and the river outflow water from Gahwacheon flow through the Sacheon bay, the Jinju bay and the Daebang waterway to the outer sea. The particles dropped on the estuary of the Seomjingang, the outer part of the Gwangyang bay, the inner part of the Gwangyang bay and the Yeosu strait, which belong to the Gwangyang bay area, were found to move to the Jinju bay area through the Noryang waterway, and the particles which move from the Jinju bay area to the Gwangyang bay area through the Noryang waterway are small. The most significant influence on salinity change in the study area through the freshwater diffusion experiment was identified as river outflow water of the Seomjingang. If the flow rate is applied during flood, the effects of the river discharge water in the Gwangyang bay, the Gangjin bay, the Jinju bay, and the Sacheon bay areas were found to persist until 50 days after the flood. If the Noryang waterway closed, the tidal harmonic constant amplitude of the Jinju bay area has been reduced due to a significant change in the water level and the phase has increased, the sea exchange rate between the Gwangyang bay area and the Jinju bay area is going down, residence time has increased. In addition the effect of river outflow water in flood time is found to last longer, as a result, the Noryang waterway linking the Gwangyang bay area and the Jinju bay area plays a major role in ensuring the smooth circulation of sea water within the two closed inner bay, and in particular, the sea water in the Jinju bay area contributes greatly to ensuring good communication with the outer sea.