« PreviousContinue »
in safety would be a serious problem; the old designer of the works must have been a highly intelligent man to overcome it so successfully. Besides this he made every effort to reduce the quantity of the earthwork to a minimum; to effect this the line of the bank was twisted about in order to avoid low ground, in a manner never found in later works of large size.
In about 300 B.C., King Paṇḍukābhaya, the grandson of Paṇḍuwāsa Dēva, made the Abhaya tank at Anuradhapura (Mah., i, p. 43); this is the earliest constructive work which
can be identified with certainty in Ceylon. Subsequent references to it in the histories, as well as an inscription left at it in the tenth century, containing the orders of King Kassapa IV prohibiting fishing in it, in which it is mentioned by name, prove that it is the existing reservoir at Anuradhapura which is now termed Basawak-kulam. The first duty assigned to me on my arrival in the island in 1873 was the survey of this interesting reservoir, at that time almost useless, having a large breach through the embankment, in front of which a low temporary dam of sticks and earth held back a little water; its restoration was undertaken immediately afterwards from the designs then prepared.
It is sometimes mentioned casually in the early part of the histories—in the time of Paṇḍukābhaya and subsequently— but always as a reservoir in working order; and it appears to have remained unbreached as long as Anuradhapura was inhabited— that is, for more than 1500 years, a respectable record for a work of such early date. Of no structures can it be said more truly than of reservoirs, that the most successful works have no history. Decade follows decade, century succeeds century, and while the work is performing its functions satisfactorily there is nothing in its life that is worth recording, except the levels of the water in it year by year. Naturally, therefore, we find nothing noted regarding the state of this tank.
Compared with Paṇḍā-waewa its area is insignificant; when full it only covers 255 acres, although it appears to have been a little larger originally. Yet it was well designed to fulfil its purpose, the storage of rainfall close to the town, for the water-supply of the city and for bathing purposes. the best of a very poor catchment area; had it been supplied with a higher embankment it would have failed to secure much more water in years of ordinary rainfall. Owing to the small area from which the surplus rainfall flowed into it there would be no difficulty at it, like that experienced at Paṇḍā-waewa, from very high floods, either during its construction or afterwards.
The plan of the tank on Fig. 70 shows that a much shorter bank might have been carried across the valley in a south-east line from the flood-escape to a projecting point on the opposite side of the reservoir; but this would have removed the water nearly half a mile further from the early city, whereas the evident aim of the designer was to construct the tank as close to the town as possible. He therefore ran the bank to a position lower down, where on the eastern side the ground level was below that of the water to be retained. From this point he turned the line in an up-stream direction, at nearly a rectangle, until higher ground was encountered. This turning of one end of the embankment upstream is a special feature of the Anuradhapura reservoirs, Paṇḍā-waewa, and Sangili
Kanadara tank, described below, and is not found elsewhere in Ceylon, I believe, excepting in the tanks of the Mannār district, where the configuration of the ground, which is practically a sloping plain, rendered it unavoidable.
The embankment is 5910 feet long, or 1 miles. As now restored, its crest is 22 feet above the sill of the sluice; but originally it appears to have been six feet higher, judging by the levels of its more elevated portions. It was considerably eroded, and for a great part of its length the top was below the level adopted at the restoration. The width of its crest was only from six to eight feet, but the slopes on both sides were flatter than at Paṇḍā-waewa, being at the rate of 3.1 feet horizontal to one foot vertical. The slope adjoining the water was protected by a layer of small boulders (Fig. 138).
A single sluice was built near the western end; it consisted, as usual, of a stone-lined rectangular well near the waterlevel, and a stone culvert for discharging water. This was a work of later date than the embankment, a number of pillars and other stones removed from pre-existing buildings being used in its construction. After it was built a small rice field was formed on the low side of the embankment.
Floods were allowed to escape round the west end of the embankment, through a slight hollow 22 feet wide, the level of which was 19 feet above the sill of the sluice. The present flood-escape is 3 feet 8 inches lower. The original area of the reservoir was about 330 acres, and its capacity about 133 million cubic feet.
There is nothing in the design of the embankment which is indicative of its antiquity. The slopes of the sides were similar to those of many later works, and the weak section which appears to be a primitive characteristic of Pandawaewa is thus absent. At a little later date it will be seen that it became the custom to make them still flatter. In view of the general features of the design, I am of opinion that several other embankments of considerable size had been constructed in Ceylon before the works at Abhaya-waewa were undertaken.
Another reservoir made by Paṇḍukābhaya at the same city, before Abhaya-waewa was formed, appears to have been a somewhat large one. The Mahavansa relates of it (i, pp. 42, 43), Causing his uncle's canopy of dominion to be brought, and having washed it in the natural tank that was here, this Paṇḍukābhaya caused himself to be anointed king with the water of that very tank. . . . Having deepened the abovementioned marsh, he made it contain a great body of water. By his having been anointed with that water as a conqueror (Jaya) it obtained the name of Jaya-vāpi.'
The old name having been changed, this reservoir has not been identified. If it had an embankment and was not
merely an excavated pool, and if it also covered a large area and was near the town, as the extract would lead one to suppose, it may have occupied the site of Tissa-waewa, the next tank of which I give particulars.
The illustration (Fig. No. 117), from a sketch made by me in 1873, shows a large natural pool in the bed of Tissawaewa. It is not unlikely that an embankment may have been raised on the low side of this sheet of water, along the line of the present embankment of Tissa-waewa, so as to retain a better supply during the dry seasons, before the construction of Abhaya-waewa. There is some evidence of this in the name of a long channel that was subsequently cut in order to lead water from the great Kala-waewa into Tissa
waewa; it bore the name Jaya-ganga, 'the Jaya river'; this may indicate that it was the channel that conveyed water into the Jaya tank.
A third reservoir at Anuradhapura, termed Gāmani-vāpi, is referred to (Mah., i, p. 43) as being in existence to the northward of Abhaya-waewa during the reign of the same king. The name has been changed, and the tank has not been identified. The time of its construction is uncertain; as the father of Paṇḍukābhaya was named Gāmaṇi the tank may have been constructed by him. According to the Mahavansa he lived at Anuradhapura. Its winding embankment indicates a possibility that the shallow tank now called Peramiyan-kulam is this work.
Soon after the middle of the third century B.C. King Dēvānam-piya Tissa formed the Tissa tank at Anuradhapura (Mah., i, p. 79). The account of the incident which led to the erection of the Miriswaeți dăgaba by King Duṭṭha-Gāmiņi proves that this is the reservoir on the south-western side of the dãgaba; it still bears the original name. According to the story in the history, the king had gone to bathe in Tissa-waewa, and had set up his sceptre in the ground at the side of it. When he had finished his bath and wished to take away the sceptre it was found to be miraculously fixed, and immoveable. The dāgaba was built by the king immediately afterwards, close to this reservoir, and enclosing the sceptre, in order to commemorate the miracle.
The valley in which the reservoir was made is very shallow, and the design took a peculiar form in consequence. A straight bank was raised across the lower part of the ground for nearly three-quarters of a mile, running nearly north and south. From each end of this a long arm was carried in an up-stream direction, forming an obtuse angle with the central part, and being continued until ground was met with sufficiently high to prevent the escape of floods. If Paṇḍukābhaya raised an embankment at this place, it must have occupied the line of the central straight part of this bank.