The Vewa and
Ancient Sri Lanka boasts a distinguished hydraulic
civilization. The technology used to construct the irrigation tanks of Sri
Lanka is unmatched, and has long confounded and fascinated acclaimed irrigation
engineers such as Henry Parker (a British hydraulic engineer who served in the
Department of Irrigation during the 1880s).
The Vewa (irrigation tank) and the lives of ancient
villagers were and still are intrinsically interconnected. If there wasn’t a Vewa
to be seen in a particular area there was neither a paddy field nor a village
in the vicinity. The Vewa, aside from fulfilling water and irrigation
requirements of the Sri Lankan people, was also the quintessence of the grand
and extensive cultural ethos of ancient villagers. The use of the irrigation
tanks and the water and agricultural traditions associated with them has been
passed down through generations and are still present today.
The importance of these tanks to the people of the
nation can also be derived from the fact that a village within the vicinity of
a particular Vewa was, more often than not, named after it - for example,
Siyambala Vewa, Athavatuna Vewa, etc. The Vewa was a common asset of the
villagers and as such every villager was responsible for its maintenance and
Many of the Sri Lanka’s kings insisted in
constructing irrigation tanks in an effort to generate wealth for the country
and improve the lives of its people. The capacity and prominence of ancient
kings was assessed by the number of irrigation tanks he had constructed.
Construction of irrigation tanks requires a large
labor force as well as irrigation engineers. The labor force was provided food
for the period of their employment; thus, the economic and political stability
of the country often played a significant role in deciding when a large scale
irrigation tank can be constructed. Administration of the Vewa was assigned to
a person called the ‘Vew Vidane’.
Tank Bund (Vew Bamma): The Vew Bamma is made of soil that is pressed and
pounded to ensure strength. In the past, animals such as oxen and goat were
driven over heaps of soil several times to compact it. It holds water inside
Sluice Gates (Sorowwa): Sluice gates are constructed to release water into
paddy fields for irrigation. There are two parts to a sluice gate called the
Mada Sorowwa and the Goda Sorowwa. The Mada Sorowwa is located at the bottom of
the tank and expels the mud accumulated there. The Goda Sorowwa releases water
into paddy fields. Sluice gates can be divided into two categories based on the
technology used. The technology used in the construction of valve pit/tower (Bisokotuwa)
in large scale irrigation tanks is particularly applauded. The Bisokotuwa takes
the shape of a well and is made of granite. It follows a sophisticated water
regulating system called ‘Mohola’ which releases the right amount of water at
the right time. A ‘log sluice gate’ is set up in small scale Vewas; cylindrical
logs are arranged on top of each other. These Vewas can be emptied completely
by taking off the logs.
Surplus Weir (Pitavana): Pitavana is constructed to protect the tank bund
from damage during heavy rainfall by discharging excess water. The excess water
travels through a small stream called ‘Van ela’. Water discharged from the
surplus weir does not cause any harm to paddy fields.
Stone Liner (Ralapanava): This is a granite stone liner constructed on the
inside of the tank bund to prevent it from being eroded by the water current.
Silt and debris are retained at the Vew Thavalla and prevents them from flowing
into the water within the irrigation tank. Many trees, creepers and vines can
be found in the Vew Thavalla which helps retain the silt and debris. For this
reason, clearing the Vew Thavalla was restricted in ancient times.
The Diyakata Pahana measured water level of the Vewa; if the level was too
high, the sluice gates were opened releasing excess and if the level was too
low releasing water into paddy fields was done more restrictively and
Other uses of
Apart from irrigation, tanks were also used for many
other purposes such as fishing, bathing, washing clothes, and bathing animals.
Different areas of the tank were used for different
purposes; ‘Diya Mankada’ is the area used to obtain drinking water; the water
in this part of the Vewa is therefore cleaner than any other part. The ‘Nana Mankada’
is reserved for bathing and is located at a distance from the Diya Mankada and
always down from it so the water from the bathing area does not reach the
drinking area. The area allocated for bathing is shallow and does not get muddy
even after extensive use. ‘Rada Mankada’ is the portion dedicated to washing
clothes, and the ‘Boradiya Mankada; is the place used to bathe working animals
such as oxen and Buffalos.
Refurbishment is done during the dry season when the
water of the tank has dried up. An auspicious day is decided by the Vew Vidane
to commence refurbishment. Each part of the Vewa is apportioned to a particular
villager and he is responsible for cleaning and protecting it from damage.