Tuesday, March 10, 2009

The river for Jaffna peninsula project

by Thiru Arumugam
The Jaffna Peninsula has an area of 1000 square km and has no rivers and is totally dependent on the annual rainfall of about 1270 mm, of which about 87% falls during the north-east monsoon from October to December, for recharge of the water table in the underground limestone aquifer. In the past, water was drawn from wells for domestic and agricultural use by well sweeps, but from the 1950’s onwards pumps have been used to draw water from about 100,000 wells in the Peninsula. Over pumping for agricultural use has drawn down the fresh water stored in the limestone aquifer resulting in sea water percolating into the wells through the fractured limestone, as no part of Jaffna is more than about 15 km from the sea.

About 60% of Jaffna is occupied by residential usage, home gardens, roads, parks etc.; about 13% (13,700 hectares) is cultivated with food crops and about 13% (13,000 hectares) is cultivable with rain-fed rice paddy. 4% of the land is not arable due to soil salinity and the balance 10% of the Peninsula is occupied by two lagoons, which are presently saline. At present about 30% of the wells in the Jaffna Peninsula are saline. Recent reports from agricultural experts state that more than 4500 hectares of fertile agricultural land have turned saline and are unsuitable for cultivation.

Within the Jaffna peninsula there are two large lagoons, the Vadamarachchi lagoon and the Upparu lagoon with surface areas of about 77 and 26 square km respectively. These lagoons cover a significant proportion (10%) of the peninsula’s land area of 1000 square km. These lagoons have openings to the sea and are salt water lagoons but during the north-east monsoon rain water from their catchment areas also collects in them. Paddy cultivation in the Jaffna Peninsula is essentially rain-fed cultivation. Cash crops and market garden crops are, however, irrigated using well water from a long time ago. The Colonial Secretary, Sir James Emerson Tennant in 1857 compared these with the market gardens in Fulham and Chelsea in the suburbs of London.

The earliest known recorded observation about improving the fresh water situation in the Jaffna Peninsula was made nearly 350 years ago. Hendrile van Reede, Captain to the Dutch Governor Rijckloff van Goens, stated: "A dike to contain the sea at Condemanaer and Navacolli, with sluices to claim the rain water and a canal to the salt pans at Nieweli would create more useful arable land."

To increase the availability of fresh water in the Jaffna peninsula we need to look at sources alternative to rain in the peninsula. South of the peninsula is the sea water Elephant Pass Lagoon which has a surface area of about 77 square km. It has a catchment area of about 940 square km in the mainland Vanni, consisting mainly of the Kanakarayan Aru. During the north-east monsoon surplus rain water from the Vanni is discharged into the Elephant Pass lagoon. From this lagoon this fresh water flows into the sea through the eastern end at Chundikulam and formerly also through the western end Elephant Pass bridge, and was being wasted.

During the 1950’s a scheme was proposed to utilise the monsoon rain water running to waste from the Elephant Pass lagoon, for the benefit of the Jaffna peninsula

Full Story: Island