Repairs to Giant’s Tank after two decades’ neglect

[TamilNet, Thursday, 01 May 2003, 12:33 GMT]
Repair work on the long neglected Giant’s Tank (reservoir) in Mannar began Thursday under the World Bank North East Integrated Agricultural Project (NEIAP). The ancient reservoir feeds 160 minor irrigation tanks in mainland Mannar. The reservoir’s 10 sluice gates were opened Thursday to drain its waters for the repairs.

The reservoir, known as Kattukaraikulam in Tamil, directly irrigates more than 24,000 acres of rice fields. It can hold 30500 acre/feet of water and has a catchment area of 38 square kilometres. (A catchement is the high ground from which rain and jungle stream waters collect in a reservoir)

Awed by it’s size, early colonial travellers named the ancient reservoir the Giant’s Tank.

The Giant’s Tank is in danger of breach in 20 points on its bund, due to more than two decades of neglect by successive governments in Colombo. Wave action had caused erosion in the bund at these points, critically weakening its capacity to withstand the pressure of the reservoir’s great volume of water. The Giant Tank’s bund is 23760 feet long.

“The tank’s full supply level is 11.56 feet. But we never let it rise to more than 10 feet because the bund could breach and flood the lands and villages below”, Mr. Ganeshalingam Saravanabhavan, Irrigation Engineer for Mannar told Tamilnet’s Mannar correspondent.

Last year, following the signing of the ceasefire between Colombo and the Liberation Tigers, the Irrigation Department made ad hoc efforts to patch the eroded embankment. In December 2002, a dangerous breach brought about by heavy rains filling the reservoir was averted by a hurried piling of sandbags on the weakened section of the embankment.

Under the NEIAP repair plan, the bund will be reinforced with riprap according to Mr.Ganeshalingam.

(A riprap is a foundation or sustaining wall of stones thrown together on a soft bottom under water or on an embankment slope to prevent erosion).

The engineer said that it will take a month for the waters in the reservoir to drain fully and that the authorities have duly informed farmers not to cultivate lands irrigated by Giant’s Tank during this season.

“But we are not going to wait until the waters drain completely. Work will start as soon as a section of the embankment is dry”, the engineer said.

During the war, the reservoir was totally neglected as there was a ban on cement, iron for sluice gates etc., and because Colombo did not release funds for the maintenance of irrigation tanks in many parts of the northeast. The Giant’s Tank suffered immensely since 1997 when it became part of the forward defence lines separating the LTTE held part of the Mannar district from that controlled by the Sri Lanka army.

Sluices were opened at the sole discretion of the SLA and later the STF. Fishing was banned in the reservoir. Sri Lankan armed forces in the area regularly opened the Giant Tank’s sluices to net fresh water fish that teemed in the reservoir and sold the catch in Colombo.