Southern Drought Clear Even from Space... Reservoir Bottoms Exposed

As heatwaves and droughts continue in the southern regions, the water levels in major dams and reservoirs have dropped sharply, exposing their bare bottoms clearly captured from space.

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

With even soil moisture decreasing in the southern regions, experts pointed out that mid- to long-term water resource management measures must be strengthened to prepare for 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 plummeted 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 the US satellite company Planet confirmed that water remained only in a narrow section near the water intake, with the entire reservoir exposing its bottom.

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

As the storage rate in the South Gyeongsang Province region dropped to a critical level, Korea Rural Community Corporation President Kim In-jung visited Okcheon Reservoir on the 4th to inspect drought countermeasure operations.

Daegok Dam in Ulsan, which is showing the lowest storage rate among water supply dams, also saw its water surface area decrease by 55.4%, dropping from 1.268 square kilometers on July 30 of last year to 0.566 square kilometers on July 30 of this year.

As water has almost disappeared in the upstream tributary sections of the dam, the riverbed is clearly visible over a wide area.

Okjeong Lake in Imsil, which was formed by the 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 reduction of water was particularly visible in the upstream tributaries and the eastern vicinity of Okjeong Lake.

In the southern regions, the cumulative precipitation over the recent 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 is the fourth lowest rainfall recorded since nationwide meteorological observation networks were expanded in 1973.

Based on satellite data from the National Aeronautics and Space Administration (NASA) Soil Moisture Active Passive (SMAP) satellite, Telepix analyzed soil moisture changes across South Korea, revealing a clear contrast where soil moisture increased in areas north of the central region, while it decreased in the southern regions.

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

By province, the average decrease 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 Hye-ri, a senior researcher at the Telepix Rapid Analysis Team, said, "As the southern region experienced continuous rainfall shortages this summer amounting to only half the past 10-year average, droughts have generally intensified, with storage rates and water body areas dropping significantly and soil moisture declining." She added, "In particular, the storage rates of Daegok Dam and Okcheon Reservoir have fallen to around 10%, making continuous monitoring and preparations for water shortages necessary."

Experts emphasized that measures must be established as water resource management becomes increasingly difficult due to compound occurrences of drought and heatwaves, increasing disaster frequencies, and widening regional precipitation gaps.

Professor Yeseong Wook of Ewha Womans University explained, "The drought in the southern region is a drought-heatwave compound disaster, which is a representative type of compound disaster." He noted, "Because the heatwaves and droughts accompanied by compound disasters are greater in intensity than single-hazard heatwaves or droughts, their damages are also massive."

Professor Kug Jong-seong of Seoul National University said, "In the future, the possibility of repeating droughts and heavy downpours may increase, with prolonged periods of no precipitation alongside short and intense heavy rainfalls when it does rain." He added, "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 outlooks, 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 storage facilities."

Oh Jae-ho, CEO of Nano Weather and professor emeritus at Pusan National University, said, "Climate disasters are not isolated events, but compound disasters where heatwaves, droughts, wildfires, and water quality degradation trigger one another." He stressed, "Since there are limits to responding solely with dam, water supply, wildfire suppression, and disaster alert systems built upon past climate standards, the redesign of social infrastructure reflecting latest climate risks and preemptive integrated responses are urgent."

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