East Asia: Vast surpluses forecast for Upper, Middle Yangtze, esp Hanjiang River

26 October 2017

The Big Picture
The 12-month forecast map for East Asia (below) indicates extreme to exceptional water deficit conditions in Mongolia and across the border into northern China. Moderate to severe deficits are forecast for a large block in southeastern China including Zhejiang, Fujian, Taiwan, and northern Guangdong, and, in Liaoning and North Korea.

Primarily moderate deficits are forecast in southern South Korea, and in eastern Hokkaido and southeastern Honshu, Japan.

Surpluses of varying severity are forecast for: the Han River (Hanjiang) watershed, an eastern tributary of the Yangtze; the Middle and Lower Yellow River (Huang He); Shanghai; northwestern Jiangxi; the western Pearl River (Zhujiang) watershed in the south and around the Gulf of Tonkin; Qinghai; Tibet; northeastern Jilin; and north of the Bohai Sea in far eastern Inner Mongolia.

Impacts
Heavy rains in central China have killed 23 people, forced the evacuation of nearly 34,000, and caused direct economic losses estimated at 3.26 billion yuan (US$490.3 million). Affected regions include Chongqing Municipality and the provinces of Anhui, Henan, Hubei, Sichuan and Shaanxi. Rainfall and increased discharge from the Danjiangkou reservoir caused flooding on the Hanjiang River, a tributary of the Yangtze, in Hubei. Authorities ordered the release of water from 146 swollen reservoirs and suspended shipping services and construction projects. Floodwaters inundated Yueliangwan Wetland Park in Xiangyang, Hubei.

As Taiwan headed into its dry season, water officials expressed concern over comparatively low water levels in reservoirs at the beginning of October. Recent downpours have replenished Feitsui Reservoir to 95 percent capacity, but Zengwen Reservoir serving the Chiayi area rose to only 62 percent. Taiwan's Water Resources Agency says optimum conditions for this time of year are as close to full capacity as possible, enough to last until the dry season ends in May.

Severe drought in North Korea continues to impact agricultural production and food supplies, and the UN Food and Agriculture Organization has called this year's drought the country’s worst since 2001. Evaluation of the primary cereal-growing provinces of North Pyongan, South Pyongan, Pyongyang, North Hwanghae, and South Hwanghae using satellite data suggests overall production this year is much lower than last year.

In response to North Korea's weapons development program UN sanctions have expanded to include banning Pyongyang from exporting coal, iron, lead, seafood and textiles, but includes no restrictions on food imports. In August China shipped 45.8 times more corn to DPRK than in August of 2016, and 54 times more wheat. 

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

Recent exceptional deficits in Mongolia and Inner Mongolia are expected to diminish somewhat in the near term – October through December – as will deficits on the Korean Peninsula and in Liaoning, though severe deficits will persist in northern North Korea. Widespread severe to extreme deficits will emerge in Zhejiang, Fujian, Guangdong, and Taiwan. Exceptional deficits in northern Sichuan are expected to disappear, but moderate to severe deficits will emerge in western and eastern regions of the province.

Widespread intense surpluses are forecast for a vast stretch of the Upper and Middle Yangtze River through Shanghai, Jiangsu, Anhui, Hubei, Henan, and Shaanxi. Surpluses are expected to be exceptional in the Han River (Hanjiang) watershed. Severe surpluses will continue to emerge along the Middle and Lower Yellow River (Huang He). Surpluses in the western Pearl River watershed and around the Gulf of Tonkin are forecast to diminish somewhat. Intense surpluses will continue to emerge in eastern Qinghai while intense deficits are forecast in the west. Both surpluses and deficits are forecast for Tibet and Xinjiang as deficits emerge.

After December, severe to exceptional deficits are forecast to re-emerge across southern Mongolia and in China, reaching from Xinjiang through Inner Mongolia. The extent of extreme deficits in northern North Korea will increase, and deficits in southeastern China will diminish somewhat. Widespread surpluses will persist from Jiangsu through southern Shaanxi; surpluses along the Middle and Lower Yellow River will transition to conditions of both surplus and deficit as deficits emerge; and surpluses in the western Pearl River watershed will continue to diminish.

The forecast for the final months, April through June, indicates a similar pattern of water anomalies as in the prior three months but with diminished severity overall.

(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.

Comment

Many analyses reported in ISciences-authored blog posts are based on data generated by the ISciences Water Security Indicator Model (WSIM). Other sources, if used, are referenced in footnotes accompanying individual posts. WSIM is a validated capability that produces monthly reports on current and forecast global freshwater surpluses and deficits with lead times of 1-9 months at 0.5°x0.5° resolution. This capability has been in continuous operation since April 2011 and has proven to provide reliable forecasts of emerging water security concerns in that time-frame. WSIM has the ability to assess the impacts of water anomalies on people, agriculture, and electricity generation. Detailed data, customized visualizations, and reports are available for purchase.

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