Fresh water for Jaffna farmers

by Dhaneshi YATAWARA

The North of Sri Lanka is different from the rest or the country in its geography and culture. Its agricultural concepts and practices have the rich inbuilt qualities. For the Northerners agriculture is the main economic base. Facilities promoting agricultural sector bear a significant impact on their economic life.

Located in the dry zone of Sri Lanka, Jaffna, faces shortage of water vital for its agriculture. There are no streams or rivers in the Jaffna Peninsula, where the land is largely flat. In addition, the topography does not permit construction of reservoirs. This makes ground water the potential source of the peninsula. Paddy cultivation is essentially rain- fed.

Cash crops and cottage garden crops are mostly irrigated using well water.

The Jaffna peninsula largely depends on the annual rainfall of about 1270mm received mostly during October to December monsoon rains. The rain water is collected in wells and it is believed that in the entire peninsula roughly about 100,000 wells exist. Meanwhile, water pumps came into use since 1950s.

The supply of adequate fresh water has been the perennial problem of the peninsula. Studies have already shown that due to over exploitation of the aquifer in Jaffna peninsula most wells have become brackish. Thus it is essential to meet the increased demand for supply of fresh water.

The reconstructed Thondamannaru Barrage. Pic: Chaminda Hithetiya

Work in progress at the Muthalikkuli Salt Water Exclusion scheme in Kayts

Valukkaiaru main channel work in progress

Maintenance work in progress

"Over pumping the fresh water in the limestone aquifers permits sea water percolation through the fractured limestone as no part of Jaffna is more than about 15 kilometres from the sea. Now about 30% of the wells are saline," Engineers Thiru Arumugam, K. Shanmugarajah and D.L.O. Mendis states in 'A River for Jaffna' article published in a Colombo daily in August 2008.

The article was published to commemorate the 103rd Birth anniversary of Senior Engineer Sanmugam Arumugam, an acknowledged authority on the country's water resource. The salt water intrusion has its serious impact on the ground water level, water quality, soil salinity and related environmental problems.

In 1859, British Colonial Secretary Sir James Emerson Tennant described the importance of well water for agriculture in Jaffna, as follows: "The value of these wells is extreme in a country where rivers and even the smallest stream are unknown, and where the cultivators are entirely dependent on rains of two monsoons. But such has been the indefatigable industry of the people, that may be said to have virtually added a third harvest to the year, by the extent to which they have multiplied the means of irrigation around their principal towns and villages".

Sir Tennant continues to describe the market gardening that existed in Jaffna. He says, "In the immediate vicinity of Point Pedro (and the description applies equally well to the vicinity of Jaffna and the Western Division of the Peninsula in general), the perfection of the village cultivation is truly remarkable; it is horticulture rather than agriculture, and reminds one of the market gardens of Fulham and Chelsea more forcibly than everything I have seen out of England. Almost every cottage has a garden attached to it, wherein are grown fruit trees and flowers, the latter being grown in great quantities for decorations and offering in the temples. Each is situated in a well-secured enclosure, with one or more wells."

Historical phases

According to historical records, it was nearly 350 years ago was the earliest known proposal was made to improve the fresh water in the peninsula. It was Dutch Captain Hendrile va Reede who conceived the idea of improving the fresh water supply in the peninsula.

In 1879, Government Agent Twyneham proposed that dams would prevent salt water from entering the lagoons, which he withdrew later.

Then in 1916 Government Agent Horsberg suggested that as an experiment the reaches of Vadamarachchi lagoon be made into a fresh water lagoon by blocking some culverts. This was done in 1920. The scheme operated successfully for four years but was not made permanent.

Then as records indicate in 1940s the Divisional Engineer Webb, had produced detailed plans for the Thondamannaru and Ariyalai barrages.

Construction works of the barrage at Thondamannaru had started following the World War II in 1947 completed in 1953. Then, later the Ariyalai barrage, where the Upparu lagoon connects the sea, was completed in 1955. Due to years of negligence and difficulties in maintaining these barrages the wooden gates and stop logs perished and sea water has started passing through them freely.

Arumugam plan

Engineer S. Arumugam published 'A River of Jaffna' in 1954 which later became famous as the 'Arumugam plan'. The Arumugam plan proposed to utilize monsoon rain water from the mainland streams for the benefit of Jaffna people.

As Engineer Mendis has mentioned in his article the openings in the road and rail bridges in Elephant Pass causeway at the Western and Elephant Pass lagoon were closed to prevent fresh water going to the sea.

A bund has been built in the 1950's at the Eastern end of Elephant Pass lagoon at Chundikulam to isolate Elephant Pass lagoon from the sea, with a spill way provided to discharge excess flood water to the sea. With these alterations, the lagoon turned in to a fresh water lagoon but the Chundikulam bund breached by heavy floods allowing sea water to flow in to the lagoon.

At the Annual Sessions of the Institution of Engineers, Sri Lanka in October 2007 a resolution on improving fresh water lagoons was handed over to President Mahinda Rajapaksa.

A sum of Rs. 100 million was released for restoration of Thondamannaru barrage. The work is now completed thus initiating the process of making the Vadamarachchi lagoon a fresh water lagoon.

Also in the Arumugam Plan, a 40 feet wide 2.5 miles long channel, called the Mulliyan Link Channel was proposed from the North Eastern side of the Elephant Pass lagoon to convey fresh water from the Elephant Pass lagoon to the Vadamarachchi lagoon at its southern end. This included regulatory gates to control the flow. Unfortunately as reports indicate, only about two and a quarter miles of channel was completed in the 1960's.

Another link channel has been built between Vadamarachchi and Upparu lagoons so that the fresh water from Elephant Pass lagoon can be supplied to Upparu Lagoon via Vadamarachchi lagoon. At present, the gates are no longer water tight and sea water seeps in to the lagoon.

At the moment, about 11,000 acres of land bordering the Vadamarachchi and Upparu lagoons are uncultivable. There will be a dramatic improvement of the 30% of wells in Jaffna which are now saline.

"Fresh water prawn farming can commence on the banks of the lagoons, with potential for export earnings. Converting the Elephant Pass lagoon into a 30 square mile fresh water lagoon will provide fresh agricultural possibilities on both sides of the lagoon i.e. the Jaffna peninsula side on the North and the Vanni side on the South, once the salinity has been leached from the soil," Engineer Mendis states in his article.Repairing of the Arialai Barrage, which is under the consideration of the present development plan of the Government, will greatly contribute to the improvement of the fresh water in Jaffna.

Rain water

According to reports the peninsula originally had about 1000 small ponds which collected the North East monsoon rain water. But at the moment many of these ponds are neglected and silted due to poor maintenance. The authorities have already planned to initiate a project to reconstruct, rehabilitate and improve and desilt these ponds.

Future

The ground water is the potential for water resources development of the Jaffna peninsula. Of the 1000 square kilometers of the Jaffna peninsula about 60% are covered by dwellings, home gardens, roads, parks, public buildings. About 13% is cultivated with food and subsidiary crops and 13% is cultivable with rain-fed rice paddy. 4% is not arable due to salinity. Another 10% is covered by the two lagoons. Recent reports from agricultural experts conclude stating that more than 4500 hactres of fertile agricultural land have turned saline and have become unsuitable for cultivation. Thus the uncultivable lands can be treated for soil salinity if the water table gets stable with more fresh water seeping in.

The supply of adequate fresh water has been a perennial problem of the people of Jaffna. And it is important at this stage to ensure an adequate supply of water meet the increased demand.