연구보고서
- 저자
- 전종안 박사
- 작성일
- 2017.07.04
- 조회
- 202
- 요약
- 목차
Sea-levels can rise due to expanding seawater resulting from ocean warming and by melting ice over land due to climate change. It is widely known that sea-level rise contributes to the increase of seawater intrusion on coastal groundwater systems. The objectives of this report are to investigate the impacts of sea-level rise on coastal groundwater systems and to provide recommendations to control
seawater wedge through the SUTRA model. We collected and analyzed tide gauge station data to project sea-level rise based on the tide gauge station data at the Gunsan station. In addition, freshwater recharge rates were estimated using the precipitation projection data provided by the Korea Meteorological Administration. The observed electrical conductivity at the Byeonsan1 and Byeonsan2 monitoring wells for seawater intrusion were used to estimate the transport parameters for the study sites. The changes in salinity at the monitoring wells for a total of 15 scenarios including the baseline period (2005-2015) were investigated with the combinations of 4 sea-level rise projections (0.12m sea-level rise by 2050 with linear regression, 0.32m sea-level rise by 2050 with polynomial regression of order 2, 0.57m sea-level rise by 2050 under Representative Concentration Pathway (RCP)4.5, 0.72m sea-level rise by 2010 under RCP8.5) and 4 freshwater recharge rates (0.00627kg s-1 in 2050s under RCP4.5, 0.0058kg s-1 in 2050s under RCP8.5,
0.00549kg s-1 in 2090s under RCP4.5, 0.00694kg s-1 in 2090s RCP8.5). While 0.72 sea-level rise contributed to the largest increase in salinity at monitoring wells without consideration of the changes in freshwater recharge rates, 0.57m sea-level rise with a freshwater recharge rate of 0.0058kg s-1 contributed to the larges salinity increase. The effect of the Saline Groundwater Extraction method on seawater intrusion was also investigated through the SUTRA model. The results showed that when both top and bottom extraction pumps were run, the seawater wedge could be effectively controlled. These methods were also used for the pacific island countries for this study. However, due to the data availability, the simulation of seawater intrusion was conducted with an island from a previous study that can adequately represent a pacific island country. For Samoa, rises of 27.61cm and 98.36cm in sea-levels by 2050 were projected with linear regression and polynomial regression of order 2. Based on this result, the effect of a rise of 1m in sea-level
on seawater intrusion was investigated with the SUTRA model. The results showed that the sea-level rise contributed to the increase in salinity at the monitoring well, which was assumed to be installed at a depth of 40m at the center of the island. It is concluded that this study can be useful to secure water resources by efficaciously controling the seawater wedge and subsequently leads to the
reduction of saline damage to crops.