Severe drought highlights
China's water scarcity
by Zhang Zhongsheng
For centuries, China has been economically plagued by either spring drought or summer floods and sometimes both in the same year. Barely two years after the devastating 1998 summer floods involving two-thirds of the country, a severe drought hit large parts of the nation this spring -- comparable to droughts in 1928-1929 and 1972 and 1978.
Hardest hit areas include north China and many places along the Yellow and Huaihe rivers. About half a million hectares of land were affected and 80 million farmers were suffering from temporary shortages of drinking water. Summer grain production will drop by a big margin. Conditions in the north did not improve until early July, when it began to rain again.
Several factors account for the harshness of the current drought. Lack of rainfall comes first, with the spell of dry weather lasting over 200 days in some places. Partially responsible are global warming and the greenhouse effect which speed up evaporation. In north China, a higher frequency of sandstorms this spring and heavy drought last summer aggravated the situation. Lack of national, unified control over, and optimal allocation of, water resources also play a part.
On top of that, while paying close attention to floods, which often entail instant human deaths, local officials tend to ignore drought not understanding that the consequences may turn out to be even more enduring, devastating and widespread. As a result, insufficient funds have been provided for irrigation projects over the past two decades.
With 49 million hectares of irrigated land, China has more than any other country. This compares with some 46 million hectares in India and 20 million in the United States, the countries ranking second and third in irrigated area. Far more important to China than to those two nations, irrigation covers roughly half of the total cropland area and accounts for nearly four-fifths of the all-important grain harvest.
Irrigation has led to much more intensive land use. In some cases, land that once produced a single crop of rice, now produces two or three a year. In other cases, wheat is grown as a winter crop, and rice as a summer crop -- both irrigated. The net effect was a substantial increase in the multiple cropping index, without any appreciable gain in the actual cropland area.
In the half century since 1949, the growth in irrigation has come from two sources. Until about 1970, most of it came with the development of surface water resources from dams. The water was backed up and then diverted onto the land, usually through gravity-fed canals. Since 1970, however, most of the additional irrigation has come from tapping underground water. Some 2 million wells now supply water for irrigation.
But over-pumping has led to falling water tables in northern China. The province most heavily affected is Hebei, which surrounds both Beijing and Tianjin. One tenth of Shaanxi Province's farmers even face chronic shortages of drinking water. In regions where pumping rates exceed aquifer-recharge rates, the amount of water pumped will eventually be reduced.
Even so, future water needs are expected to continue growing at a rapid pace. Each sector -- agriculture, industry and residential -- will be demanding far more water a few decades from now than today. The combination of a population reaching 1.6 billion by 2030 and the continuing use of individual consumption of livestock products, could nearly double the demand for grain over current levels. Industrial water needs could also easily double within a decade. As incomes rise and transition to modern living styles progresses, residential water needs will also climb.
The per capita availability of water resources in China is 2,300 cubic meters, or one- fourth of the world average. It is listed as one of the world's most water-scarce nations.
The severe drought this year has lent urgency to the 46-year-old plan to bring water to northern China from the Yangtze River, which empties one trillion cubic meters of water into the sea annually. An outline of south-north water diversion programs will be set forth this year and listed in the country's 10th Five Year Plan (2001-2005) and the 2010 long-range program.
The gigantic engineering project diverting water from upper, middle and lower reaches of the Yangtze, would alleviate to a certain extent water scarcity in the north. This project will perhaps remind Americans of their own successful Central Valley water diversion project in the 1930s. The proposed engineering project in China will be much bigger in scope and far more complicated in design.
Other relevant policies have also been put in place. They include among other things, raising water prices, heightening efficiency in water use, purifying and recycling of sewage, utilizing seawater and so on. This will also accelerate the on-going readjustments in farm produce mix in anticipation of China's WTO entry. Less water-demanding crops will be encouraged in north China.
The severe drought this year will once again serve as a wake-up call for valuing every single drop of water.
Zhang Zhongsheng is a senior engineer at the Ministry of Water Conservancy.