Minister of Climate, Environment and Energy Kim Sung-hwan (second from right) and South Jeolla-Gwangju Special City Mayor Min Hyeong-bae (third from right) visit Dongbok Dam in Hwasun-gun, South Jeolla Province, to discuss plans for using the dam to supply water. [Yonhap]
Minister of Climate, Environment and Energy Kim Sung-hwan (second from right) and South Jeolla-Gwangju Special City Mayor Min Hyeong-bae (third from right) visit Dongbok Dam in Hwasun-gun, South Jeolla Province, to discuss plans for using the dam to supply water. [Yonhap]

The expansion of Dongbok Dam — a key water source for the Honam semiconductor cluster — will proceed by constructing an entirely new structure rather than raising the height of the existing dam, officials said Sunday.

According to the South Jeolla-Gwangju Integrated Special City, the city and the Ministry of Climate, Environment and Energy determined that raising the existing dam by about 15 meters was not feasible due to safety concerns, and revised the plan to build a new dam instead.

A ministry review found that adding a 15-meter structure on top of the existing dam — increasing its height from 44 meters to 59 meters — would subject the structure to water pressure it could not withstand.

The plan was therefore changed to build a new, structurally reinforced dam from the ground up at a site 200 meters downstream from the current dam, designed to handle the greater volume of water.

The new dam will stand 59 meters tall, surpassing the current structure, and is expected to increase Dongbok Dam's storage capacity by more than 100 million tons — from 99.5 million tons to over 200 million tons.

As the new dam is built, the existing structure will be demolished in stages. A temporary upstream storage facility will be constructed in the interim to ensure an uninterrupted water supply.

Stone and other materials recovered from the demolition of the existing dam will be recycled in the construction of the new one.

The Ministry of Climate, Environment and Energy plans to finalize the revised project design and begin construction in the second half of next year.

The dam is set to be completed by 2030, when the Honam semiconductor complex is scheduled to open at the site of Gwangju's military airport, and will supply water for semiconductor manufacturing and other uses.

The government plans to deliver a total of 650,000 tons of water per day to the semiconductor cluster by 2030 — 300,000 tons from Dongbok Dam, 150,000 tons from the Juam and Jangheung dams, 100,000 tons from the Boseonggang Dam, and 100,000 tons from Naju Dam.

Authorities are also pursuing a plan to convert Dongbok Dam, which currently serves as Gwangju's drinking water source, into a multipurpose dam under national management.

As the project moves forward, the flooding of upstream areas and the relocation of affected residents are expected to become major points of contention.

If the water level rises by 15 meters, an estimated eight to 10 villages and 266 households in upstream areas of Hwasun-gun and Damyang-gun are projected to be submerged.

"The Dongbok Dam expansion is intended to secure both industrial water and Gwangju's residential water supply in preparation for increasingly erratic rainfall patterns driven by climate change," a city official said. "A study on flood damage from the dam expansion is currently underway, and we will draw up countermeasures based on the findings."


sij@heraldcorp.com