[News Terms] 'Jihasu Reservoir Dams' Built on Islands and Remote Areas

The 'groundwater storage dam' is a drought response facility that artificially installs a water barrier underground to prevent the outflow of groundwater. On islands or remote areas without rivers, groundwater flowing beneath the surface is blocked and stored by a dam, allowing it to be used as domestic water during droughts. It is considered a relatively low-cost solution to alleviate drought. It is also called 'underground dam' or 'groundwater dam.' Article 9, Paragraph 6 of the Groundwater Act refers to it as 'groundwater dam.'

Unlike conventional dams, groundwater storage dams (underground dams) do not cause flooding areas. The aboveground space can be utilized to the maximum extent. Even though the embankment height is not high compared to regular dams, the rise in water level affects distant areas, resulting in a large storage effect. Being underground, the possibility of water pollution is low, and there is almost no loss due to evaporation. The minimal environmental impact is its greatest advantage.

Aerial view of the groundwater storage dam in Daeejakdo area, Ongjin-gun, Incheon City, completed in 2020.
[Photo by Ministry of Environment] [Image source=Yonhap News]

However, since the facility is not exposed above ground, investigation, design, and construction are relatively more difficult than those of conventional dams. Advanced technology is also required for safety inspections and maintenance of the facility. Additionally, as groundwater levels decrease due to dam construction, ground subsidence may occur, so appropriate water level management capabilities to prevent ground subsidence are necessary.

On the 16th, the Ministry of Environment announced plans to install underground dams in 10 locations nationwide, including Yokji-myeon (Yokjido) in Tongyeong-si, Gyeongnam Province. The 10 locations where underground dams will be installed include Yokjido, Deokjeok-myeon (Deokjeokdo and Soyado) in Ongjin-gun, Incheon; Yangdong-myeon, Yangpyeong-gun, Gyeonggi Province; Yeongok-myeon, Gangneung-si, Gangwon Province; Sangchon-myeon, Yeongdong-gun, Chungbuk Province; Namyang-myeon, Cheongyang-gun, Chungnam Province; Yeonghae-myeon, Yeongdeok-gun, Gyeongbuk Province; Jusan-myeon, Boryeong-si, Chungnam Province; and Soan-myeon (Soando), Wando-gun, Jeonnam Province.

Construction will begin in the first half of the year in Yokjido, Deokjeokdo, and Yangdong-myeon, while design will proceed for the remaining seven locations. The Ministry of Environment has allocated a budget of 10.8 billion KRW for the groundwater storage dam project this year.

According to the recently established 'Mid- to Long-term Strategy for Securing Groundwater Resources Facilities,' the Ministry of Environment has prioritized 80 promising sites nationwide for groundwater storage dams and plans to increase the number of underground dams to 20 by 2030 and 80 by 2053. Underground dams were installed in three locations: Daeejakdo in Ongjin-gun, Incheon in 2020; Anmado in Yeonggwang-gun, Jeonnam in 2021; and Bogildo in Wando-gun last year.