Basic Concepts and Management Issues of Rivers - River Dynamics and Integrated River Management - page 31

while agricultural and industrial water demands as well as navigation requirements shall also be considered
and taken care of.” From the early 1950s to the late 1970s, while the total water use in China increased by
four times, the urban water use and industrial water use (inclusive of thermal power water use) increased
by eight and twenty-two times respectively. The quality of urban water sources is required to meet the
Standards for Environmental Quality of Surface Water and the quality of municipal tap water to meet the
Standards for Domestic Drinking Water in China. The mutual relation between water supply and drainage
not only lies in the necessity of rationally and timely draining of wastewater, which is equivalent to 60%
to 70% of water supply, but also in the necessity of reusing a certain amount of the wastewater after being
properly treated. More than two thirds of the cities draw their supplies or part of their supplies from
groundwater in the country, and about one fourth of the national public water supply capacity comes from
groundwater. Urban water supply is the main purpose of water resources development.
The total water demand of the country is 530 billion m 3 at present. It will increase to 1100 billion m 3
in 2040, thence the water demand will remain at that level. At present, about 500 billion m 3 of water are
used. The speed of water resources development will lag behind the increasing water demand. The
amount of water shortage will increase from 30 billion m 3 to 100 billion m 3 . Inter-basin water transfer
projects are the main strategy to ease the water shortage. Seven short distance inter-basin water transfer
projects have finished, including the Luanhe-Tianjin water transfer project, the Yellow River-Qingdao
project, and the Biliuhe-Dalian project. The long distance inter-basin water transfer projects from the
Yangtze River to north China have been launched. The total capacity of the three routes—the east route
from Yangzhou to Tianjin, the middle route from Danjiangkou to Beijing, and the west route from the upper
reaches and the tributaries of the Yangtze River to the Yellow River is 40-50 billion m 3 . Water shortage
can only be partly eased but not solved by these transfers. New strategies are needed.
1.2.2 Flooding
Several devastating floods have occurred worldwide in the 1990s, with a long list of flood events each
killing more than a thousand people or causing material losses in excess of one billion U.S. dollars
(Kundzewicz, 1997). A number of extreme floods of exceptional severity have occurred in the 1990s. A
100-year flood occurred on the Rhine River with stage at Cologne at 10.69 m just 13 months after the
previous one in 1993 with stage at the same place 10.63 m. The 1993-flood on the Mississippi river has
been regarded as the most devastating flood in the modern history of the United States. Flood records on
the main stem of the Mississippi were broken at several observation stations by up to 1.2 m. In St. Louis,
Missouri, the previous record stage was exceeded for more than three weeks. In China, five flood events
killing over 1,000 persons each occurred in the period 1990-1998, and according to the Munich Reinsurance
(Munich Re, 1999) there have been 24 flood events in the world that caused total losses in the excess of
one billion U.S. dollars each. The highest flood losses of the order of more than 20 billion U.S. dollars
were recorded in 1996 and 1998. The 1998 floods on the Yangtze River, Songhua River and Nenjiang
River and the 1996 floods on the Yellow River and Haihe River were highest events in terms of flood stage,
economic loss, and the impact on the environment, society, and flood control strategies.
The flood losses in China quickly increased in the 1990s. Figure 1.24 shows the flood losses in 1991-1999
compared with the average annual loss in the 1980s (Cheng, 2002). In the 1990s the flood loss (8 Yuan =
1 U.S. dollar) is much higher than the flood loss in the 1980s. In 1996 and 1998 the flood losses were
over 200 billion Yuan. One reason for the ever-increasing flood loss is the development of the economy,
the other reason is the increasing flood hazard.
As shown in Fig. 1.25 the high flood risk areas in China are mainly the areas surrounding the lower
Yellow River and the middle and lower Yangtze River, the Haihe River basin, the Huaihe River basin, and
the Songhua River and Nenjiang River basins. These areas are densely populated and have been rapidly