Drainage technology used for collecting rainwater, that dates back
to the time of the Ming and Qing dynasties (1368-1911), is to be
used for modern greenery in Beijing in an effort to boost rainwater
collection and irrigation.
The antique technology dating back to China's Ming and Qing
dynasties can be found in the Circular Wall (Tuancheng) of Beihai
Park, a superbly well preserved imperial garden in Beijing, is to
be widely used in the capital's urban greenery construction,
according to sources from the municipal park authority. Adoption of
this antique technology is expected to promote efficient rainwater
collection and the irrigation of grassland.
The 4,500-square-meter Circular Wall in the park is actually a
round terrace with rich vegetation. Groundwater from the terrace
for fostering vegetation is far from enough. However, gardening
experts have found that all the antique trees and other plants in
the Circular Wall are growing quite well.
To
explain the situation, the Beihai and Jingshan parks under the
administration of Beijing Municipal Bureau of Parks launched a
two-year research project on the antique rainwater technology used
in the Circular Wall. Experts discovered an underground circular
drainage system in the terrace where at each turning point there
was a pit to collect rainwater and create a backflow. Via this way,
underground water was collected and reserved and used to irrigate
the trees. History of these collecting pits dates back to the Ming
and Qing dynasties almost 600 years ago.
The irrigation work of grassland around the Second-Ring Road of
Beijing has been set to use this irrigation technology.
Seventy percent of the ground area of Beijing is occupied by
construction, roads and waterproof areas, leaving less than 30
percent of soil for grassland. However, urban grassland plays an
important role in conserving groundwater resources, reducing
surface water runoff and supplementing the amount of urban
underground water.
Beside Beihai and Jingshan parks, Longevity Hill (Wanshoushan) in
the Summer Palace and Beijing Botanical Garden has also taken
measures to collect rainwater for irrigation.
(China.org.cn by Zhang Tingting April 5, 2003)