History of Technology in India, Vol. I: From Antiquity to c. 1200 A.D. v1.c32.s2.t2.7

v1.c32.s2.t2.7

“The water of the lower tank, excavated later on, shall not irrigate the field (already) irrigated from the higher tank; and the natural flow of water from a higher to a lower tank shall not be stopped, unless the lower tank has ceased to be useful for three consecutive years” (AS. II. 9). The real significance of this injunction laid down by Kauṭilya is that there was such a system of carrying the surplus water of one tank to another in ancient times. We have two classic instances from the south. The Vīranārāyaṇa eri or Viranam tank (first half of the 10th century A.D.) is at the fag end of the Kaveri delta near Kattumannar Koil (South Arcot District) and 8 miles west of Gaṅgaikoṇḍasolapuram (Tirucirappalli district). The bund of the extant reservoir alone is 10 miles in length and has amean width of some 3 miles. “The circumference of the tank when it is full is nearly 25 miles” (GAAD, 1906, p. 132). The surplus water of the famous ‘Colaganam’ tank (now in ruined condition) constructed by the Cola Rajendra I in 1012-14 A.D. at Gaṅgaikoṇḍa-solapuram went to make up this tank through a canal. Another interesting instance comes from Karnataka. A Kannada inscription (IA, VI. No. 32, pp. 138 ff.) dated 1096-97 A.D. from Kāṭṭageri (Bādāmi Taluk, Katadgi district) refers to the existence of a ‘Larger Big tank’ during the rule of the Western Calukya ruler Vikramaditya VI. J.F. Fleet, who identified the place and the tank based on the inscription, attributes three reasons for the sustained water supply in that area after in situ inspection of the place. “The system of tanks at Kāṭṭageri was formerly a large one. First, there is the small tank, on the west of the Fort, and close under the walls ... Secondly, there is a larger tank, on a slightly higher level, which if repaired, would, when full, include the proceeding in itself, formed by an embankment running to the south from just below the south-east corner of the Fort. And thirdly, about 1/4 of a mile away to the south-east of the proceeding, and on a lower level there are the remains of a large embankment, now breached and quite useless, which when in repair, evidently formed a tank of considerable area”. From the above description, it is discernible that the method of draining the surplus water from the tank at the higher level to the tank at the lower level must have been successfully applied in this case. These two instances prove that the ancients had a sound knowledge of hydraulic engineering while planning and executing the irrigation works.