As heatwaves and droughts persist in the southern regions of South Korea, satellite imagery has clearly captured major dams and reservoirs sharply losing water and exposing their parched beds.

The surface area of Okcheon Reservoir in Changnyeong, South Gyeongsang Province, has shrunk by nearly 90% compared to a year ago, while water levels have also significantly decreased at Daegok Dam in Ulsan and Okjeong Lake in Imsil, North Jeolla Province.

Amid declining soil moisture in the southern regions, experts pointed out that mid- to long-term water resource management measures must be strengthened to cope with compounding disasters where heatwaves and droughts coincide.

According to data analyzed by satellite startup Telepix on the 9th comparing satellite imagery from last year and this year, the water surface area of Okcheon Reservoir dropped by 88.8%, from 0.129 square kilometers on July 29 of last year to 0.014 square kilometers on August 1 of this year.

The analysis of satellite imagery from U.S. satellite company Planet confirmed that water remained only in a narrow section near the water intake facility, with the entire reservoir exposing its bottom.

The storage rate of Okcheon Reservoir plummeted from 82.5% on the filming date last year to 11.1% this year.

As the reservoir storage rate in the South Gyeongsang Province area dropped to critical levels, Korea Rural Community Corporation President Kim In-jung visited Okcheon Reservoir on the 4th to inspect drought response measures.

Daegok Dam, which records the lowest storage rate among water supply dams, showed a 55.4% decrease in its water surface area, dropping from 1.268 square kilometers on July 30 of last year to 0.566 square kilometers on July 30 of this year.

With water almost disappearing in the upper tributary sections of the dam, wide stretches of the riverbed are clearly exposed.

Okjeong Lake in Imsil, which is formed by Seomjin River Dam and supplies agricultural water to the Honam Plain, saw its water surface area decrease by 34% from 13.25 square kilometers on August 1 of last year to 8.74 square kilometers as of August 2 this year.

Telepix analyzed that the recession of water is clearly visible particularly in the upper tributaries and the eastern areas of Okjeong Lake.

The southern regions recorded a cumulative precipitation of 212.1 millimeters over the past two months up to the 6th of this month, which is only 46.8% of the average precipitation for the same period in normal years.

This marks the 4th lowest rainfall since nationwide meteorological observation networks were expanded in 1973.

According to Telepix's analysis of soil moisture changes across South Korea based on data from the U.S. National Aeronautics and Space Administration (NASA) Soil Moisture Active Passive (SMAP) satellite, a clear contrast was observed where soil moisture increased in areas north of the central region while decreasing in the southern regions.

Soil moisture changes are expressed as the volumetric ratio of water to soil volume (cubic meters per cubic meter).

Broken down by province, the average reduction was largest in Ulsan at -0.1268 cubic meters per cubic meter, followed by South Gyeongsang Province at -0.0983 cubic meters per cubic meter, South Jeolla Province at -0.0489 cubic meters per cubic meter, and North Jeolla Province at -0.0181 cubic meters per cubic meter.

Kim Hyeri, a senior researcher at the Telepix Rapid Analysis Team, said, "As the southern region has continued to experience rainfall shortages at about half the level of the past 10-year average this summer, droughts have generally intensified, with storage rates and water body areas dropping significantly alongside low soil moisture." She added, "In particular, Daegok Dam and Okcheon Reservoir have seen their storage rates plunge to around 10 percent, requiring continuous monitoring and preparations for water shortages."

Experts emphasized that measures must be established as water resource management becomes increasingly difficult due to the rising frequency of disasters driven by concurrent droughts and heatwaves, alongside widening precipitation gaps across regions.

Professor Y예상욱 at Ewha Womans University explained, "The drought in the southern region is a representative drought-heatwave compound disaster. Because heatwaves and droughts accompanied by compound disasters are greater in intensity than single-hazard heatwaves or droughts, their damages are also severe."

Professor Kook Jong-seong at Seoul National University said, "Moving forward, the possibility of recurring droughts and torrential downpours may increase, where prolonged periods of no precipitation are accompanied by short and intense heavy rains when it does rain." He added, "We must understand regional precipitation amounts, rainy days, downpour intensity, and soil moisture changes based not only on short-term forecasts but also on seasonal predictions and multi-decadal climate projections, and reflect them in mid- to long-term national disaster mitigation policies, such as the operation of dams and reservoirs, allocation of agricultural and industrial water, and expansion of urban drainage and storage facilities."

Oh Jae-ho, CEO of Nano Weather and professor emeritus at Pusan National University, stated, "Climate disasters are not isolated events, but complex disasters where heatwaves, droughts, wildfires, and water quality degradation cascade into one another. There are limits to responding solely with dam, water supply, wildfire suppression, and disaster warning systems built on past climate baselines, making the redesign of infrastructure reflecting the latest climate risks and proactive integrated responses urgent."

(Photo: Provided by Telepix, Yonhap News)