A River for Jaffna

map.jpg (23193 bytes)by S. Arumugam
Jaffna with a scanty rainfall which can sometimes be only 30" is different from the other parts of the northern province which enjoy a rainfall of over 60" during the year.

To convey the beneficial aspects of the abundant rainfall from one part of the province to another which is bereft of such bounty, is a legitimate aspiration for agricultural development.

The late K. Balasingham, Member of the Legislative Council, visualized early in the 1930 decade, the utilization of the lagoons by their conversion into fresh water lakes. His criterion was the oft-repeated saying of Parakrama Bahu the Great that "not a drop of rain should be allowed to flow into the ocean without profiting man".

These led to the consideration of the full utilization of the flood waters of Kanagarayan aru, the main river in the northern province. The aru has its source in Vavuniya and passes through Puliyankulam Mankulam area to fill Iranamadu tank.

The surplus flow enters the Elephant Pass lagoon, i.e., the lagoon to the east of Elephant Pass bridge, and goes to waste in the open sea, through the large bridge at Elephant Pass.

One day in the month of February 1949, a family travelling on the road had stopped on the road near the Elephant Pass bridge, for their picnic lunch. When washing their hands in the water the fond father was heard explaining to his little son’s inquiries the reason for the presence of fresh water on the east side of the road in spite of the west side being open sea.

The little boy’s impetuous response was "Let us bring some earth in our car and fill up the bridge, then there will be fresh water always!".

That year the Kanagarayan aru had a copious flow; the Iranamadu irrigation tank had filled and been spilling. The surplus flow had filled the lagoon to the east of the road, and though the Iranamadu tank had stopped spilling in January, the water in the east lagoon was still fresh even in February. But it would soon become brackish due to sea water entry through the bridge unless some earth was brought and filling done.

Perennially fresh

That the water in the eastern side of the road should remain fresh throughout the year, forms the basis of the Elephant Pass Fresh Water Reservoir project on which work is in progress.

The Elephant Pass lagoon receives the waters of the Kanagarayan aru, Nethsali aru, Perementhal aru, Theravil aru, and other streams, and covers an area of about 11,400 acres stretching from Elephant Pass to Chundikulam.

It is bounded by Vanaekulam to the north and by the Karachchi lands to the south. With the erection of an obstruction near the bridge and suitable embankment spill near Chundikulam, the fresh water that enters the lagoon will form the Elephant Pass Fresh Water Reservoir. A link channel to the north through Mullian area connects this reservoir to the internal lagoon within the Jaffna peninsula usually known as the Vadamarachchi lagoon.

The Vadamarachchi lagoon is a long sheet of water connecting from Mulliyan in Pachchilaipalai, spreading through Chempiyanpattu, Eluthumadduval, Varani, Karaveddi, Vallai Veli, and connects with the sea near Thondamannar near Valvettithurai in Vadamarachchi. It also branches off at Sarasalai, and extends towards Jaffna town connecting up with the sea at Arialai near Chemmani.

It is about a mile wide, and as it extends more or less right through the heart of the peninsula, it is an ideal store house influences life in the peninsula. As a result of the 600 foot barrage recently completed at Thondamannar, entry of sea water has been cut off and is prevented from entering this internal lake, which was originally the Thondaiman Aar.

Three items

The nature of work envisaged to be done at Elephant Pass consists of three items:

A dam by the side of Elephant Pass bridge would conserve and save the flood waters of Kanagarayan aru, and also would in addition prevent any entry of sea water from the open sea in the west.

A one and a quarter mile roadway dam and spill built across the lagoon at its eastern end at Chundikulam would ensure the safe discharge of surplus flood waters and will also in addition prevent salt water ingress from the eastern ocean.

While these eastern and western structures would help to receive and store in safety, the fresh water flood flow, the third item, viz., a link canal will convey the water thus stored to the heart of the Jaffna peninsula.

On completion of these works, the Kanagarayan aru flood waters would first be utilized in leaching out the brackishness present in the Elephant Pass (primary or parent) reservoir, and in the Vadamarachchi (secondary or service) reservoir, simultaneously.

The primary reservoir with its clayey bed will respond much quicker than the secondary with its alluvial bed, to these leaching out measures. Though the process of leaching cannot obviously be concluded for some time, yet there would hardly be any delay in reaping the beneficial aspects.

The benefits will commence immediately, and improve more and more with each rain season. Moreover, it is well known that partially brackish water, though not fresh to the palate, is nevertheless useful for cultivation needs, as is the case with the water found in many wells in the coastal regions of the peninsula.

Inland lake

As days go by the heat of the sun during the months of February, March, April etc., will cause considerable evaporation in the reservoirs. Each day the amount of water lost in the secondary will be supplied to it by the primary through the canal, and the secondary will therefore continue to be full, (being supplemented every day), as long as flow from Elephant Pass reservoir is possible.

Such conditions could go on till the southwest monsoon in June, July cause enormous evaporation which it may not be possible to supplement.

In effect this will result in having an inland lake in the Jaffna peninsula. The benefits that will accrue to the lands in the Jaffna peninsula as a result of having a vast fresh water lake will be many-fold.

It would tend to make the underground water table copious and raise its level; the level of water in the wells would be higher as years go by. Moisture will be prevalent in the sub-soil. Plant life will become luxurious; gone will be the days when trees and coconut palms get scorched and drop in the hot season.

That this work will benefit the agricultural development of the neighbouring area of over 15,000 acres is beyond doubt. It will also cause the flow of Kanagarayan aru waters from its source in Vavuniya district through the Jaffna district and over the spillway at Thondamannar and at Ariyalai in the outskirts of Jaffna town.

(The writer is a former Deputy Director of Irrigation. This article was first published in October 1954.)