the four seasons. At the same time he must strive to nourish the best in all creatures,
bring order to the feudal lords and barbarian tribes surrounding the country, and
within the state to win over the common people and see to it that each of the other
ministers and officials performs his proper duties.’^18This advice urged a non-intrusive style of management and emphasized
harmony. The emperor was to follow the trend of nature to attain the goal of
balancing yin and yang sides of the cosmos. In the early imperial system of
China, this balancing policy helped consolidate the political legitimacy of the
emperor. Because the emperor was the Son of Heaven, his mandate to rule
depended on maintaining order between nature and humans as well as among
the people. One sign of loss of the mandate was the inability of dynasties to
avert floods, famine and drought. The ‘king’s way’(or wang dao) required that
attention be paid to conservation, but within the framework of human-centered
values.
Preserving nature and consolidating power were regarded as twin objectives
in the Chinese imperial tradition at the early stages. The record of early
dynasties was mixed with respect to environmental preservation. A significant
ecological achievement of the Qin Dynasty (221–209 BC) was the huge water
diversion project engineered by Li Bing and his son at Dujiangyan. For more
than two millennia it has controlled the flow of water from the Min River into
the Chengdu Plain of Sichuan. Construction, renovation, and expansion of
China’s Great Wall and Grand Canal, however, denuded adjacent lands of
forests and altered ecosystems.^19 We present the Dujiangyan case in greater
detail.
The Dujiangyan irrigation system lies on the Min River (Minjiang) to the
northwest of Dujiangyan City in Sichuan. It was built over 2200 years ago
under the direction of Li Bing, governor of the Shu Prefecture in the Qin State.
The major purpose of construction was to manage water flow of the Minjiang
to facilitate irrigation of the Chengdu Plain and to enhance water conservation.
After a careful survey of the area, a channel was cut through Mount Yulei
in the west of Sichuan, creating a man-made river. A dike divided the river into
two parts: the inner river and the outer river. In order to control floods and
discharge silt, two spillways were built at the end of the dike. Following
geographic characteristics of this region, the dike distributed 60 percent of the
water to the inner river, and 40 percent into the outer river during the dry
season. During the flood season, 40 percent of the water entered the inner
river, and the rest the outer river. The curved shape of the dike matched the
shape of the river. The bottom waters of the Minjiang, rich in sand, flowed into
the outer river (helping to prevent flooding) while surface clear waters flowed
to the inner river and were used for agricultural irrigation and water
conservation.
The dike consisted of bamboo cages filled with egg-sized stones; spaces
Historical patterns 23