East Asia: Widespread water deficit in Yangtze Basin

22 September 2022

THE BIG PICTURE
The 12-month forecast for East Asia through May 2023 indicates widespread water deficits of varying intensity in the Yangtze Watershed and Taiwan. Areas with exceptional deficits include the Yangtze Gorges, Jiangxi, and southern Taiwan. Transitional conditions (pink/purple) are expected in much of the Pearl River Watershed and surpluses in the south through Hainan.

In the Yellow River Basin (Huang He) and much of the North China Plain widespread surpluses are forecast. Anomalies will be extreme in the Lower Yangtze region and the North China Plain and exceptional in the Ordos Loop. Northeast China, too, can expect surpluses in a vast area from Liaoning to the Chinese border. Anomalies will be extreme to exceptional in the Manchurian Plain. Widespread, exceptional deficits will reach across a vast belt from western Inner Mongolia into Xinjiang Uygur through the city of Hami and into the Taklimakan Desert. In Tibet (Xizang), surpluses are forecast for many areas in the western half and exceptional surpluses along parts of the Yarlung (Brahmaputra) River. Central and far eastern Tibet, however, can expect deficits, severe around Tibet’s capital, Lhasa.

Surpluses and transitions are forecast in North Korea, but deficits will dominate South Korea. Japan can expect moderate deficits in southern Honshu and in Shikoku, and surpluses from Honshu’s northern tip into coastal Hokkaido. In Mongolia, deficits will be widespread in the south and west, exceptional in many areas. Pockets of surplus are expected in the east along with transitional conditions.

FORECAST BREAKDOWN
The 3-month time series maps below show the evolving conditions in more detail.

The forecast through November indicates widespread severe to exceptional deficits in the Yangtze Watershed and the southeast, dipping into the western Pearl River Basin in Guangxi and Yunnan while transitions are expected in the eastern Pearl region. Moderate surpluses will linger in the far south and deficits in Taiwan will shrink and moderate. Intense surpluses will persist in the Yellow River Watershed and North China Plain, and in the Northeast though anomalies there will shrink and downgrade somewhat. Deficits will emerge in northern Hebei and deficits and transitional conditions are forecast from western Inner Mongolia though the Taklimakan Desert in Xinjiang Uygur. In central Tibet, deficits are forecast from Dang Reyongcuo Lake to Namucuo Lake and to Lhasa, the region’s capital; intense surpluses are expected in the central west from Ang Larencuo Lake to Zhari Namco Lake.

Much of North Korea will be in transition from surplus to deficit with deficits reaching into China, and deficits will become widespread in South Korea. Some moderate deficits will linger in pockets of Shikoku, Japan. Mild surpluses will emerge in much of Honshu’s northern two-thirds and linger on Hokkaido’s coastal east, but surpluses in Honshu’s northern tip will be severe. In Mongolia, deficits are expected in the south and west, moderate overall but with exceptional pockets in the Hangayn Mountains and central Altay Mountains. Mixed conditions are forecast in the nation’s eastern half including surpluses in the Hentiyn Mountains in the north.

From December 2022 to February 2023, widespread deficits will continue in the Yangtze Watershed, Southeast China, and the western Pearl Watershed with exceptional anomalies from the Yangtze Gorges through Chongqing well into Guizhou. A few severe pockets will linger in Taiwan and moderate deficits will increase from western Sichuan into Tibet. Surpluses will persist in the Yellow River Watershed though transitions are also forecast in eastern and southern Shandong. Surpluses will continue in Northeast China with deficits near the Korean border. Deficits will increase in northern Hebei and into Inner Mongolia. Deficits in Xinjiang Uygur will intensify while deficits in the central Altay Mountains of Mongolia moderate. Though surpluses will linger along North Korea’s northeastern coast, widespread deficits are expected elsewhere on the peninsula, extreme from western South Korea into North Korea. Deficits of generally lesser intensity are forecast in southern Japan.

The forecast for the final three months – March through May 2023 – indicates surpluses in Northeast China; Shandong through Shaanxi; and Qinghai, Sichuan, and western Tibet. Areas of deficit include Hubei through Guizhou, and eastern Yunnan and western Korea.

Please note that WSIM forecast skill declines with longer lead times.

IMPACTS
Drought in the Yangtze River Basin, the worst in over 60 years, continues to impact agriculture, notably rice production in Jiangxi and Hunan Provinces, whose combined output in 2020 totaled over 20 percent of the national yield. Through August of this year, rice imports in China have increased by 42.5 percent over the same period last year. Officials in Jiangxi have distributed over 300 million yuan (US$43 million) for drought relief. Direct economic losses in the province since late June are estimated at 5.89 billion yuan (US$840 million).

Hydropower production in Sichuan Province where a whopping 30 percent of the nation’s hydroelectricity is generated, fell by 50 percent, sending domestic coal prices to their highest in 10 months as thermal plants burned 15 percent more of the fossil fuel in the first two weeks of August compared to a year ago.

Power supply shortages in Sichuan forced many major energy consumers like Toyota Motor and Foxconn Technology Group, an Apple assembler, to close for several weeks. Compounding issues, an earthquake struck the province in early September, claiming over 70 lives.

In late September, Typhoon Nanmadol hit southern Japan. The storm knocked out power to 340,000 households, and flooding and mudslides killed two people.

Several dams in South Korea’s southern extent entered severe drought stage at the end of August - the Juam Dam and the Sueo Dam. From January through August, precipitation in the Juam Dam basin was 63 percent lower than last year. Water officials are recommending conservation efforts in local governments and industrial complexes.

NOTE ON ADMINISTRATIVE BOUNDARIES
There are numerous regions around the world where country borders are contested. ISciences depicts country boundaries on these maps solely to provide some geographic context. The boundaries are nominal, not legal, descriptions of each entity. The use of these boundaries does not imply any judgement on the legal status of any territory, or any endorsement or acceptance of disputed boundaries on the part of ISciences or our data providers.

Subscribe to our monthly Water Watch List

Search blog categories

Search blog tags