Southern South Korea Seen From Space: Dried-Up Reservoir Beds Exposed Clearly

As heatwaves and droughts persist in the southern regions, satellite images have clearly captured major dams and reservoirs rapidly 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 diminishing soil moisture across the southern regions, experts pointed out that mid- to long-term water resource management measures must be strengthened to cope with compound disasters where heatwaves and droughts overlap.

According to data analyzed on the 9th by satellite startup TelePIX comparing satellite imagery from last year and this year, the water surface area of Okcheon Reservoir in Changnyeong 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 imagery from U.S. satellite company Planet confirmed that water remains only in a narrow section near the water intake, with the entire reservoir exposing its bed.

The storage rate of Okcheon Reservoir stood at 82.5% on the filming date last year, but has plummeted to 11.1% this year.

As the reservoir storage rate in the South Gyeongsang region dropped to a critical level, 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, also showed a 55.4% decrease in water surface area when compared with last year, 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 nearly disappearing from the upstream tributary sections of the dam, wide stretches of the riverbed are clearly exposed.

Okjeong Lake in Imsil, created by Sumjingang Dam to supply 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 reduction of water is clearly visible particularly in the upstream tributaries and eastern sections of Okjeong Lake.

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

This marks the fourth lowest rainfall since nationwide weather observation networks were expanded in 1973.

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

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

By province, the average decrease was greatest in Ulsan at -0.1268 cubic meters per cubic meter, followed by South Gyeongsang Province at -0.0983, South Jeolla Province at -0.0489, and North Jeolla Province at -0.0181.

Kim Hyeri, a senior researcher at the TelePIX Rapid Analysis Team, said, "In the southern region this summer, continuous rainfall shortages—remaining at about half of the past 10-year average—have led to a worsening drought overall, with sharp declines in reservoir storage rates and water body areas, alongside lower soil moisture." She added, "In particular, the storage rates of Daegok Dam and Okcheon Reservoir have fallen to around 10%, necessitating continuous monitoring and preparation for water shortages."

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

Professor Ye Sang-wook of Ewha Womans University explained, "The drought in the southern region is a representative drought-heatwave compound disaster, which is one of the typical compound disasters. Because the heatwaves and droughts accompanied by compound disasters are more intense than single disasters, their damages are also massive."

Professor Koo Jong-seong of Seoul National University stated, "Going forward, the possibility of recurring droughts and torrential downpours is growing, characterized by prolonged dry periods alongside short and intense heavy rainfalls when it does rain. We must understand regional precipitation amounts, rain days, rainfall 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 dam and reservoir operations, agricultural and industrial water allocation, and the expansion of urban drainage and detention facilities."

Oh Jae-ho, head of NanoWeather and professor emeritus at Pusan National University, said, "Climate disasters are not isolated incidents, but compound disasters where heatwaves, droughts, wildfires, and water quality degradation trigger one another. There are limits to responding solely with dam, water supply, wildfire extinguishing, and disaster alert systems built on past climate standards, so the redesign of social infrastructure reflecting the latest climate risks and preemptive integrated responses are urgently needed."

(Photo provided by TelePIX, Yonhap News)
※ Please note: This article was translated by AI and may contain errors.