Drought: Driest Mannar produces best paddy harvest

Yoda Wewa, completely empty and dry except for a small stream of water in the tank bed. Fishing boats, now useless, parked at the base of the tank bed

The country is going through a massive drought; with some officials claiming it to be the worst drought in 40 years. The Disaster Management Centre says the drought has affected six provinces in the country and 1,150,728 persons have been affected. 

Newspapers inform areas including Hambantota, Ampara, Moneragala, Kilinochchi, Kebithigollewa, Wellawaya and Polonnaruwa are among the worst affected by the drought. Farmers complain their paddy cultivations have been destroyed and demand compensation from the Government.

Last week I had the opportunity of travelling to Mannar and was pleasantly surprised by the vast acres of lush paddy fields by the road side. Travelling along the Medawachchiya-Mannar road, the bund of the Giant’s Tank (Yoda Wewa) lies to the right for a few kilometres. Unless one climbs on to the small tank bund, water will not be visible. Yoda Wewa is situated about 25km southeast of Mannar.

On the left of the road for kilometres were vast acres of paddy, mostly mature; few fields have already been harvested and they all seem to be doing well with no signs of drought or drying up.

For most of us, Mannar reminds us of school days, when our geography teacher drew a map of Sri Lanka and marked two areas, Hambantota and Mannar, as the most arid regions of the country. This geography lesson has made a deep impression on most people and could possibly be the reason for Mannar to receive such few visitors from outside.

Paddy cultivation in Mannar

Having completed my task early, on the return journey I had time to examine the situation in detail. Travelling around 25km from Mannar, one would meet the Yoda Wewa at a sharp bend where the bund is tallest. Upon climbing I was shocked; the Yoda Wewa was completely empty and dry except for a small stream of water in the tank bed. Fishing boats, now useless, were parked at the base of the tank bed. The stream in the tank bed brought water and discharged through a sluice into a canal supplying water to the paddy fields. Nearly 3km further on the road another sluice discharged water into a channel. 

There was no stored water in the tank, but it is clear that a canal formed in the lake bed delivered a continuous flow of water. The water originates from Malwathu Oya, the original source of water for generations. The diversion canal from Malwathu Oya delivering water to Yoda Wewa runs parallel to Medawachchiya road and crosses the road near Km 50 post. 

Malwathu Oya originates in the Anuradhapura District, which is affected by the dry period. Today, Malwathu Oya also collects run-off water after cultivation and livelihood water released from Mahaweli System H, which receives water from Kala Wewa and Rajangana Wewa, hence current supply independent of rainfall.

Holding stored water in Yoda Wewa is no easy task. The shallow tank spreads over a large area and the dry wind flowing across the lake would result in a large loss. Only heavy rainfall in Anuradhapura District could fill Yoda Wewa. 

Giant’s Tank (Yoda Wewa)

The Yoda Wewa is nearly circular in shape is situated about 25km southeast of Mannar in a semi-arid zone, is one of the largest tanks in the island. The tank is believed to be built by King Dhatusena (459-477) by diverting water by a 4m high stone dam built across Malwatu-oya and delivered by a 19km long canal. But some historians claim the tank was built by the Nagas, original occupants in the country prior to arrival of Vijaya who had mastered the art or the science on dam building. 

A section of the tank bund runs parallel to Medawachchiya-Mannar Road. The water from this tank feeds over 100 smaller tanks downstream and irrigates about 11,000 hectares of paddy land.

The embankment of Yoda Wewa is comparatively low with a height of 14 feet due to flat terrain, but is over 7km in length. The tank covers over 1,840Ha with a capacity of 39 million cubic meters of water. The tank commands a catchment area of 98km2. The region was known as the rice bowl of the country. But today, Malwathu water is supplemented with runoff from Mahaweli System H. 

Mannar District

Although Mannar gets comparatively low rainfall (1,250mm annually), supported by Yoda Wewa and proper agricultural practices, it produces a large crop of paddy. In 2012 the district had a population of 99,051 and a paddy cultivation of 57,041 acres or 0.576 acres per person; one of the highest paddy acreages per person in the country. When the Government imposed a 25-acre ceiling on paddy lands in the 1960s, Mannar District was the only region which did not comply, also none complained.

Mannar is not a strange place for the writer. After the ending of the 30-year war, State Engineering Corporation was entrusted with the rehabilitation of war-damaged public buildings in Mannar District to allow resettlement of displaced personnel. The writer then as the General Manager of SEC had to ensure early completion of over 100 minor projects spread throughout the district.

There is no stored water in the tank, but it is clear that a canal formed in the lake bed delivers a continuous flow of water. The water originates from Malwathu Oya, the original source of water for generations

Facing the drought

It is clear that the farmers in Mannar District commenced cultivation with the rains and with the failure of rains, fields were directly fed with Malwathu water reaching Yoda Wewa, without resorting to storage. It would have been a joint effort of politicians, irrigation engineers, Government officials and the farmers who produced the bountiful crop of paddy. How many other regions in the country could boast the same cooperative effort?

On 7 January coinciding with the Government’s two years in power, the President commenced water storage in Moragahakanda Tank and the rising water levels and efforts to save trapped animals were shown regularly on local TV. Anyway, Moragahakanda tank has no users for stored water till 2024. The tank is located on Amban Ganga two kilometres upstream of ancient Elahara anicut that diverts water to Minneriya, Giritale and Kantale reservoirs. Further downstream of Elahera diversion is another diversion, Angamedilla anicut which diverts water to Parakrama Samudraya through a 24-mile-long canal. 

Did the Government officials who planned impounding of Moragahakanda Tank during the height of a drought realise the gravity of disturbing the water supply to the paddy cultivation in the entire Polonnaruwa District? They were only concerned about pleasing the President.

Unless the politicians and agricultural officials encourage farmers to make maximum use of rain water and use stored water sparingly, there would always be water shortages and crop failures. World Bank officials at the inception of Mahaweli project warned that the Sri Lankan farmer uses the highest quantum of water for paddy cultivation in the world and unless this trend is controlled entire project would be failure. Our farmers’ water consumption has gone still higher and the Victoria Stage II has been abandoned due to shortage of water in Mahaweli.

It is about time rest of the country learn lessons on water conservation and farming from their counterparts in Mannar.