Unmun Dam in Nakdong River basin enters 'Serious' drought level as rainfall hits 8% of normal

The Ministry of Climate, Environment and Energy said Wednesday that Unmun Dam, a water supply dam in the Nakdong River basin, has entered the "Serious" drought level as of midnight, and that it will strengthen measures to conserve the dam's water reserves.

Rainfall in the Unmun Dam watershed this year has reached 371 millimeters, just 64 percent of the historical average of 581 millimeters. Since the end of the flood season (June 21 to July 14), precipitation has totaled only 18 millimeters — a mere 8 percent of the historical average of 223 millimeters.

The dam currently supplies an average of 290,000 tons of water per day, but inflows have amounted to only 160,000 tons daily, causing reservoir levels to fall steadily. Current storage stands at 47.74 million tons, equivalent to 61 percent of the historical average.

Since entering the "Caution" drought level on March 2, Unmun Dam has operated under an austerity regime that includes reducing streamflow maintenance releases by up to 100 percent on a flexible basis.

With the dam now at the "Serious" level, authorities plan to increase the alternative supply of daily water from the Nakdong River for Daegu's residential and industrial use — currently 50,000 tons per day from Unmun Dam — to a maximum of 107,000 tons per day. The alternative supply via the Geumho River for Gyeongsan's residential and industrial use will also rise from 4,000 tons to a maximum of 6,000 tons per day.

If reservoir levels continue to fall even after the "Serious" designation, authorities plan to operate the Geumho River emergency supply facility on a flexible basis to provide up to 120,000 tons of residential and industrial water per day from the Geumho River as an alternative source.

Daegu, Gyeongsan, Yeongcheon, Cheongdo-gun and Chilgok-gun — all of which currently receive residential and industrial water from Unmun Dam — are expected to face no disruption to their water supply through measures such as switching to the Daegu-Gyeongsan water system and reducing streamflow maintenance releases. Taking this into account, authorities plan to issue an "Alert" drought level for residential and industrial water in those local governments and strengthen water management systems.

Song Ho-seok, water resources policy director at the Ministry of Climate, Environment and Energy, said the ministry would "closely monitor drought response conditions, including reservoir levels and water supply status, to ensure there are no disruptions to water supply."