Associated with some ancient tanks provided with stone anicuts is this concept of the time honored device of a Biso Kotuwa. This ancient irrigation artefact is rectangular in shape of well dressed stone slabs has served as a marvellous contraption of invention of the time.
Its purpose was to store irrigation water for the purpose of stopping the overflow of the water conveyed along a stolen aqua-duct in regulating its flow of water to feed the vast tracts of rice fields. Still another purpose was prevention of siltage.
Hence this sprawling Walawe Basin nestling in the cradle of our ancient civilization in Ruhuna Rata and Sabaragamuwa has turned into one of the bountiful rice bowls of our isle, teeming with multitudes of farming communities and a host of industries could aptly boast of such relics of a past hydraulic heritage.
This refers particularly to Magama Weva/Uru Sita Weva stone anicut surmounted by a seven headed monolithic cobra In this regard, I would like to quote in the first instance from an authoritative source namely Dr. R. L. Brohier.
In the early 20th century A.D., he was a prolific author on the ancient hydraulic heritage, archaeology, history, heritage and what not. In one of his masterpiece monograph, titled ‘Ancient Irrigation Works – Part I, (1939), particularly with reference to this very Biso Kotuwa on the ancient sluice of stone of the Seven Headed Cobra stone has enlightened us thus: “The works in the upstream of embankment which fulfilled the important functions are termed as Biso Kotuwas.
This Biso Kotuwa through which was let out water into the channels had its base or floor of about fifteen fathoms square paved with quarried stone, waterway or gutter conducting the water through the Biso Kotuwa through which was 3 1/2 fathoms long, 1 1/2 wide and 1 1/2 high on all sides closely. It was of 2 1/2 by 3 feet to admit the passage of man. There were two sluices, the entrance to each of which was called Wanaya and was undoubtedly of wide influence”.
There is still another similar authoritative source reference culled from H. Parker of British times who served in Ceylon (Sri Lanka) as an Irrigation Engineer (in 1901). In his voluminous monograph titled “Ancient Ceylon” (1909), he has paid accolades to our ancient Sinhalese Irrigation Engineers thus “The Valve Pits/Valve Towers of modern times by which the overflow in large reservoirs are regulated or totally stopped. Since this being the case the ancient Sinhalese Engineers in constructing such Biso Kotuwas had established a claim to be considered the first Inventors of Valve Pita more than 2,100 years ago.
D. G. A. Perera, a Pioneer member of the Royal Asiatic Society (Sri Lanka Branch) has been a frequent guest Lecturer on those time honoured Biso Kotuwas and other ancient Irrigation structures. With special reference to these Biso Kotuwas termed as Valve pits/Valve Towers.
In a Paper titled “The Biso Kotuwa”. In Architecture and Irrigation works of ancient Sri Lanka presented at the National Archaeological Congress, in 1986 held at the Sri Lanka Foundation Institute from 28th to 30th November 1986 gave a more signified position in respect of these Ancient Biso Kotuwas in relation to ancient irrigation works thus “However in the light of further development of European Science later in the 20th century.
We may have to modify Parker’s modification to read “The Sinhalese Engineers are the first Inventors of both the Hydraulic Surge Chamber and Valve Tower and the first to incorporate both the principles in the same structure, called a Biso Kotuwa more than 2,100 years ago”.
In archaeological terms such Biso Kotuwas had the function of releasing the water by either regulating or stopping its flow completely. It had another romantic state in Royal flavour in those halcyon days when our ancient kings and queens ruled in all glory and splendour. A similar rectangular tank dressed with stone was constructed, fed by some natural spring or some rivulet, where queens and princesses bathed and frolicked in the filled up ponds.
While working in the G. O. D. B./R. V. D. B. (Gal Oya from 1955 to 1970) in clerical and field capacities. In mid 1970, I was transferred out of the Gal Oya Project to the Udawalawe Project to report to my station at Embilipitiya, I was privileged to get an official Jeep to travel down there with my family as well.
We took the route through the Moneragala/Wellawaya highway where a tiny village by its roadside Galabbedda famed for native Auyrvedic treatment for fractures. In this pastoral village turned into a paddy field we beheld this romantic spot where queens and princesses had bathed, frolicked in all merriment. The Pond was about 20 feet square with four entrances with stone steps carved on its surface which led to this square pond below. From the four entrances were four water spouts flowing through the mouths of sculptured lions.
On the walls of this Pond were fascinatingly carved figures of damsels carrying pots. This was a veritable sign that this pond was exclusively only for the Queens and Princesses of old. Close to this Pond was a heart shaped stone slab with fabulous, ornamental designs neatly carved out. These carvings were contiguous with yet another grooved space in stone to keep the vessel(Sembuwa).
This too was beautifully and artistically ornamented with cultural motifs of floral and tendrils. This vivid account has been taken from my first publication ‘Souvenirs of a Forgotten Heritage’ (1990) the chronicle of Gal Oya valley in retrospect.
From a recent news item in an English newspaper it was reported that this priceless treasure trove of heritage, fine arts and sculpture with designs and motifs was in a dilapidated state.
When we visited in 1970, in a prime state looked after by a Watcher of the Department of Archeology. Photos taken by me in 1970 are reproduced in this Article.
I would like to draw the kind attention, of the Director General of the Department of Archaeology to take proper steps to restore it to its pristine state.