Gov't to tap all available water reserves for 800-trillion-won southwest semiconductor complex

The government has reaffirmed that it can supply the 650,000 metric tons of water per day that the 800 trillion won ($519 billion) southwest semiconductor industrial complex will require.

The Ministry of Climate, Energy and Environment unveiled its water-securing plan for the southwest semiconductor complex on Tuesday.

The ministry said it would draw 50,000 tons per day from the 88,000-ton daily surplus at Dongbok Dam on the Dongbok Stream, a tributary of the Seomjin River, and direct that water to the complex.

Dongbok Dam, a dedicated water-supply dam owned by Gwangju, is one of the city's main drinking water sources alongside Juam Dam. The surplus exists because Yongyeon Water Treatment Plant — which receives and purifies water from Dongbok Dam before supplying it to Gwangju — lacks sufficient processing capacity. The ministry plans to connect Yongyeon to the nearby Deoknam Water Treatment Plant, which has spare capacity, via a pipeline to increase the total supply.

The ministry is also pursuing a plan to raise Dongbok Dam by about 15 meters to increase its storage capacity, a move it expects would yield an additional 250,000 tons per day.

The ministry said Dongbok Dam has a relatively low water-utilization rate and is surrounded entirely by mountains, meaning a height increase would produce a significant boost in storage volume.

The ministry plans to begin consultations with Gwangju on raising the dam before the end of this year, with a target of breaking ground within five years.

An additional 100,000 tons per day — drawn from the 119,000-ton daily surplus at Jangheung Dam, which currently goes unused due to lack of demand — will also be allocated to the complex.

A further 50,000 tons per day will come from Juam Dam's contracted but unused allocation. Analysis showed that 70,000 tons per day contracted for residential and industrial use from Juam Dam is not actually being consumed, and 50,000 tons of that will be redirected to the semiconductor complex.

The ministry also decided to redirect 100,000 tons per day that Boseonggang Dam — a hydropower dam upstream of Juam Dam — currently discharges into the sea (Deungnyangman Bay) for power generation, sending it instead toward Juam Dam for supply to the complex.

The ministry acknowledged that this would reduce power output at Boseonggang Dam, but said the lost electricity could be secured through other means.

The ministry is also pursuing a plan to replace the agricultural water supplied from Naju Dam with water drawn from the Yeongsan River, freeing up an additional 210,000 tons per day of industrial water.

Sewage from Gwangju's No. 1 Wastewater Treatment Plant will be purified using reverse osmosis membranes and repurposed as general industrial water, providing up to 300,000 tons per day.

This reclaimed wastewater is expected to serve as the primary water source for the semiconductor complex for uses other than ultrapure water production.

The government also plans to develop technology to remove trace contaminants from reclaimed wastewater for ultrapure water production. The Gwangju and South Jeolla Province region experienced its longest drought on record in 2022–2023, with drought conditions persisting for a combined 281.3 days in 2022 — equivalent to 77 percent of the year. During that period, storage levels at Dongbok Dam and Juam Dam fell to around 10 percent.

Concerns have been raised that the development of the southwest semiconductor complex requires contingency plans for a recurrence of the extreme drought seen in 2022–2023.

In response to that drought, the then-Ministry of Environment drew up a medium-to-long-term drought response plan for Gwangju and South Jeolla Province in April 2023.

The plan comprised a first-stage baseline response — based on the worst drought the region had historically experienced hitting all South Jeolla dams simultaneously — and a second-stage emergency response designed for an extreme drought beyond anything previously recorded due to climate change. Together, the two stages were projected to secure more than 610,000 additional tons of water per day.

The Ministry of Climate, Energy and Environment said it will build on that plan and develop a strengthened version that incorporates the water demand of the southwest semiconductor complex.