Researched and written by Mr. Rama Somasunderam retired State Secretary of the Ministry of Transport (1990) and retired Additional Secretary of the Ministry of Mahaweli (SLAS).   

This was called the Jaffna Peninsula Lagoon Scheme which is located at Elephant Pass which is located 30 miles South East of Jaffna.

The lagoon is 19,000 acres and is saline due to sea water entering from the West during the South West Monsoon, through the bride at Elephant pass and from the East, during the North East Monsoon, due to the failure of the Sand Bar opening at Chundikulam.

The projects seek to stop the seawater and thereby getting freshwater drawing down Kanagrayan Aru. It was first mooted in 1879 and later in 1928. The projects involves catchment area of 474 square miles. The length of the bund at Elephant Pass 2m 3740 feet. The length of bund and spill at Chundikulam is 1m.4700 feet. Spill is 2,000 feet in length and the link channel is two and a half miles. 

This project was known as a river for Jaffna and the main points of the scheme is:

1. Closing of the road and railway bridges at Elephant Pass so as to prevent fresh water going for this end. I believe this work has been completed.
2. Building a bund of the Eastern end of the Elephant Pass lagoon so as to prevent fresh water going into the sea at Chundikulam.  This work to be completed but the bund was breached by heavy rain which allowed sea water seep in.
3. Excavate a 12 meter wide, 4. KM wide long channel from the Northern part of the Elephant Pass Lagoon to get fresh water from the Elephant Pass to the Vadamarachchi Lagoon. This has not been completed.
4. To re do the existing Thondamanaru Barrage so as to allow discharge of flood water. At present the condition of the barrage is not satisfactory and allows sea water to enter the lagoon.   
5. A Spill Way and gates to be constructed at the Southern End of Upparu Lagoon. This is near Arialai. This should Upparu Lagoon a fresh water lagoon. It will also provide the link channel from Elephant Pass. The Pill way and Gates have been constructed but is not satisfactory and allows sea water to enter the lagoon.

In summary the following four steps have to be taken, which are as follows:

1. Recondition of the Thondamanaru Barrage.
2. To recondition Arialial Barrage.
3. Complete Mulilyan Link Channel.  
4. Complete Spill Cum Causeway.

In 1983 and 2003 the Sri Lankan government stated that they will take steps but no action was taken to date.

                                                      Project Benefits.

The project when completed will transform agricultural production and improve the quality of water as there is a problem of salinity in the wells.

About 8,000 heaters of land is cultivated with paddy in Jaffna but his is done with rainwater. About 44,000 heaters of land are not cultivated near the lagoons as they are saline. With fresh water this can be cultivated.

Converting Elephant Pass Lagoon into 77 sq.km fresh water lagoon will increase agricultural production in Jaffna in the North and the Vanni in the South.   

References

1. Water Resources of Ceylon its Utilisation and Development by S. Arumugam, 1969. 
2. K. Shanmugarajah – Water Resources Development Jaffna Peninsula, 1993.
3. Thiru Arumugam – A River for Jaffna, 1995 – 1997.