International Conference on Rain Water Cistern Systems
USA - June 1982
6: Related Topics
Rain Water Cistern Systems
East China Normal University, China
Rain catchment systems have long been used in China. People like to drink rain
water because it is cleaner than river or well water and does not have the bad
odor and taste of river or well water.
In the vast area south of the Yangtze where rainfall is abundant, rain water
cistern systems have been a common means of water supply in past years.
The method of collecting and storing rain water was rather simple. The most
available material that people used for making rain water gutters was mao bamboo,
which is very common in South China and has a thick stem, which can be hallowed
out and split into two halves for use as gutters. Since the introduction of tin
plate and galvanized iron, people have liked to use them instead of bamboo for
making gutter systems, although they are susceptible to rusting and are more expensive.
Earthenware, a traditional material used for making vessels in China, is also
available for making rain water cisterns. People use large earthenware vats as
storage cisterns. The vats have various sizes, but the largest one has a volume
of about one cubic meter. 'In appearance it is like a bowl, with an upper diameter
of about one meter or more Although earthenware is fragile, it is an ideal material
for a rain water cistern because it is less expensive and has no effect on water
In rural areas of China, an ordinary household usually has a small yard where
large earthen vats used as rain water cisterns are placed just under the gutter
systems to receive the rain water from above. When it -rains and the vats are
filled with water, wooden covers are put on them to avoid contamination and to
shut out the sunlight to prevent algae growths. No filtering process is needed,
but some alum as coagulant is generally added to remove the suspended solids.
The impurities on the bottom of the vat should be regularly cleared away. Because
mosquito larvae sometimes breed in the water, a goldfish is placed in the water
to feed on them.
In China, an average peasant may have a commodious house with a total roof
area of 50 to 100m2. As a catchment area, it is broad enough to receive
rain water for drinking, but still inadequate to provide water for other domestic
uses. Thus, river or well. water must be used for washing and other domestic uses.
Since the annual rainfall in subtropical and tropical areas of China generally
exceeds 1 000 mm, and in many regions over 1 500 mm, most of the domestic demand
for water can be very likely technically improved by using rain water cistern
systems with larger catchment areas.
In recent years, tap water has become an increasingly common source of water
in small cities and towns of China, while rain water cisterns have decreased.
However, people do not like chlorinated water for drinking because of its odor,
and some people still collect rain water for drinking.
PDF of full document (2pp, 110kb)
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