21 March 2020 | New Scientist | 37revealed the full extent of the society’s
hydraulic engineering. Using a combination of
satellite photography, coring and excavations,
the team led by researchers at the Zhejiang
Provincial Institute of Cultural Relics and
Archaeology uncovered a series of low-lying
levees, built on swampy ground to control the
flooding of the alluvial plain, and six “high
dams” further upstream, creating reservoirs
at the feet of the surrounding mountains (see
“Neolithic Venice of the East”, page 38).City of canals
Together, the dams controlled the water flow
in more than 10,000 hectares of land and were
capable of holding back nearly 6.5 billion cubic
metres of water. Carbon dating, plus an
analysis of jade artefacts found near the levees,
suggests that some of these dams were in
operation 5200 years ago, near the beginning
of Liangzhu’s existence. And they were built
to last: the Qiuwu high dam is still in use today.
Besides allowing Liangzhu’s citizens to
irrigate their paddy fields and control
flooding after storm surges, the reservoirs
fed 51 waterways. Made from natural river
courses and artificial ditches, these canals were
about 30 kilometres long in total. “Internal
communication within the town must have
been largely by boat; this was a town of canals
as much as of roads,” noted Colin Renfrew at
the University of Cambridge and Bin Liu at
Zhejiang Provincial Institute of Cultural Relics
and Archaeology in a 2018 paper. Perhaps the
closest comparison is medieval Venice or one
of the “water towns” around Shanghai that
emerged thousands of years after Liangzhu
and that attract tourists to this day.
The canal system was also used to transport
building materials, including timber and rocks,
down from the nearby mountains and into the
city through its eight water gates. Foundations
for the city walls, for instance, appear to come
from mountains to the north. “These stones
were not quarried per se using tools to cause
physical breakage, but collected from the
surface,” says Yijie Zhuang at University College
London, a co-author on the 2017 paper.
While research in Liangzhu continues apace,
discoveries elsewhere in China indicate that the
civilisation’s rise was part of a broader social
and cultural revolution. Recent archaeological
studies show that, starting more than 5000
years ago, many settlements were emerging in
the lower and middle Yangtze regions, in what
is now Sichuan province and along the lower
Yellow River. Some, including Shijiahe in the
middle Yangtze, are large enough to have >“ One of the dams
in operation
5200 years ago is
still in use today”