East Asia: Water deficits forecast for NE China, eastern Sichuan, southern Yunnan

19 July 2017

The Big Picture
The 12-month forecast map for East Asia (below) indicates extreme to exceptional water deficit conditions in Mongolia, Inner Mongolia and northeastern China, and South Korea. Moderate to severe deficit conditions are expected from northern Gansu Province extending into Xinjiang, and in southern Yunnan, and Honshu, Japan.

Surpluses are forecast from the mouth of the Yangtze River through northwest Jiangxi, Hubei, Hunan, and Guizhou which may reach exceptional severity. Surpluses are also forecast in Tibet.

Impacts
The worst drought on record in North China's Inner Mongolia Autonomous Region, exacerbated by temperatures exceeding 35°C (95°F), has affected more than 4 million people, with 2 million requiring disaster relief. Agricultural losses are estimated at 5 billion yuan (US$737 million), as 2.7 million hectares of crops and 34.3 million hectares of grassland have been rendered unproductive. More than 3,000 firefighters have been deployed to fight a fire that spread into Heilongjiang Province. The central government of China has allocated 145 million yuan (US$21.39 million) to alleviate drinking water shortages for both people and livestock in Inner Mongolia, Jilin, and Liaoning Provinces.

In an effort to combat drought, North Korea's government has reduced school hours in at least two provinces in the north - Yangang (Ryanggang) and North Hamgyong - where corn, bean, and potato crops are at risk, mobilizing high school and college students to water collective farms from 5am to 10am each day before school. Soldiers have been deployed to repair wells as drought has dried up 30 percent of the reservoirs.

In central and southern China flooding has killed at least 56 people, according to China's Ministry of Civil Affairs, forced the evacuation of 1.2 million, and resulted in direct economic losses estimated at more than 25.3 billion yuan (US$3.72 billion). The Yangtze River and its many tributaries overflowed and more than 60 rivers have risen above warning levels. The most seriously affected regions included Hunan, Hubei, Anhui, Sichuan and Guizhou. Flooding destroyed homes, damaged crops, and canceled or delayed dozens of flights. Large parts of Changsha, a city of more than 7 million people in Henan, flooded when the Xiangjing River breached its banks.

Authorities at Three Gorges Dam on the upper Yangtze in Hubei Province reduced discharge by 70 percent in an effort to control flooding and allow downstream communities to evacuate. Three Gorges and Gezhouba hydropower plants shut down 26 generators, reducing capacity by 13.52 gigawatts (GW) to just 7.5 GW. One power analyst said the size of the shutdown was unprecedented, equal to about 40 percent of demand in Shanghai at summer peak usage.

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

Recent exceptional deficits in Mongolia into northeastern China, around the Bohai Sea, and on the Korean Peninsula are forecast to moderate over the coming months, but severe to exceptional deficits will persist in western Inner Mongolia. Moderate to severe deficits will emerge in northeast China, trailing southwest into eastern Sichuan, and in southern Yunnan. Deficits on Honshu, Japan will moderate but persist.

Observed surpluses along the Yellow River are expected to normalize or transition to mild deficit. From July through September severe to exceptional surpluses are forecast for the southern Yangtze River Basin, which will moderate thereafter.

Western China is expected to see continued mixed conditions with water surpluses continuing but moderating across western Tibet. To the north, however, severe to exceptional deficits are forecast to develop over a broad region stretching from southern Mongolia, through western Inner Mongolia, across northern Gansu, and into central Xinjiang. These deficits are expected to intensify into December and the early part of 2018.

The later part of the forecast period (bottom right frame) indicates the development of moderate deficit conditions across the whole of Mongolia, northeastern China, and the eastern plains.

(It should be noted that forecast skill declines with longer lead times.)

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.