Construction affected lake levels
The lake’s reduced water level has long been suspected to be linked to the formation of potholes and underground road cavities in the region, sparking a slew of safety issues in the buildings nearby.
“We’ve requested that the Korea Rural Community Corporation inspect the lake and surrounding area,” said Kim Jun-gi, who heads the Urban Safety Headquarters of Seoul, “and the result shows that the reduced water level in Seokchon lake was affected by the construction on Lotte World Mall, subway Line No. 9 and eight other nearby buildings.”
According to the city government, the lake’s water levels hovered around 4.68 meters (15.35 feet) until 2010, and then steadily decreased until October 2013, when it hit record low of 4.17 meters.
Afterward, the city government supplied water to the lake, bringing it back up to 4.8 meters.
According to the report, the lake’s steady decline from 2010 to 2013 overlaps with the construction on Lotte World Mall, which started in November 2010, and on subway Line No. 9 in April 2012.
The city government believes the two constructions directly contributed to reduced water levels in the lake because the isotopes of the water in the lake and the water found at the construction sites were identical, and the water running underground suddenly changed direction toward the construction fields.
“Underground water in the region moves easily because the area used to be a tributary of the Han River,” said Kim Hak-jin, a city government official. “The construction on Lotte World Mall was a major factor at first, but after, when Lotte had nearly finished building at the end of 2012, subway Line No. 9 had more impact on the lake.”
However, the city government found in simulated tests that the situation is possibly temporary, and that the lake’s normal water levels may eventually recover.
Additionally, it found that the reduced water level in the lake did not have a direct connection to the formation of the potholes and underground road cavities in the region.
But Lotte Group and the Korean Water Society have opposed the Seoul government’s announcement, saying that the reduced water level has nothing to do with the construction of Lotte World Mall.
“The city government has only focused on the period before the problem surfaced, at the end of 2013,” said Park Jae-hyun, a civil and urban engineering professor at Inje University and a member of the society.
“In December, the amount of water that leaked toward the Lotte World Mall’s construction field was 270 tons, or 7 percent, while another 1,892 tons [49 percent] headed toward the subway’s construction site.”
The figures differ from those suggested by the city government, which claimed 22 percent had flowed toward Lotte World Mall and 63 percent leaked into the subway’s construction site.
BY JANG HYUK-JIN, KIM NA-HAN [firstname.lastname@example.org]