A recent heated exchange between Trade Minister Wasantha Samarasinghe and an Irrigation Department official has raised questions regarding the safety of ancient tanks islandwide.
Sri Lanka’s ancient irrigation system, which is still functional, networks thousands of small tanks and larger reservoirs to collect rainwater for use during the dry season. This keeps the country’s agriculture operational year-round, divided into two seasons – the Maha and Yala seasons.
Today, reservoirs and tanks don’t just serve agricultural purposes; some also generate electricity and provide sustenance to smaller industries centring them, such as the tourism industry. Almost all come under the oversight of the Irrigation Department and the Mahaweli Authority, but most ancient tanks have not had any internal investigations conducted on them.
Internal investigations only when necessary
Irrigation Department Director General A. Gunasekara shed light on the maintenance process of tanks and reservoirs coming under its jurisdiction. According to him, investigations into the internal structures of these water bodies are only carried out when the need arises – that is, if any issues are observed from the outside.
Earlier this month, at the Anuradhapura District Coordinating Committee (DCC) meeting, Minister Samarasinghe was caught in an exchange of words with an Irrigation Department official, after the former requested the road on the bund of the Nuwara Wewa be opened for tourism purposes.
The official was seen cautioning about the safety issues that could come with allowing vehicles to travel on the tank bund.
An official at the Anuradhapura District Secretariat said the road on the bund had been closed during the war years. However, smaller vehicles, three-wheelers, and motor cycles had used it previously as it was the shortest route from the Anuradhapura town to the Matale junction. It also provides the best view of the historic stupas in the city Anuradhapura.
As such, tourism and commerce stakeholders in the city have requested the DCC to open the road. The DCC had sent a written request on the matter to the Irrigation Department on 29 March.
“We have requested only for lighter vehicles,” said the official, adding that if there was water seepage as the Irrigation Department was claiming, then repairs must be done regardless due to the threat to the whole city.
Nuwara Wewa, which was built over 2,000 years ago according to tradition, has no records of any internal investigations or repairs since it was built, according to Gunasekara. This is the case for many ancient tanks and reservoirs, as the Irrigation Department only looks at the internal structures if it perceives a need for doing so.
Irrigation Department limitations
“We are observing water seepage from the bottom of the Nuwara Wewa. However, to stop water seepage, we need to cut the bund and rebuild it or drain the tank for a season and build a clay wall inside it from the front,” said Gunasekara.
Prior to deciding on the course of action, the Irrigation Department has to undertake an internal investigation. However, Gunasekara said the Engineering Geology division – which carries out investigations – was currently understaffed.
“The machines to check soil quality etc. cannot be taken out because the division needs at least four storekeepers. Currently, we only have one storekeeper, so the storage units are closed because there is no one to take responsibility for the machines. Whereas 320 engineers are required for irrigation, we only have about 150. We need the approved cadre to carry out our duties,” he added.
For the Irrigation Department, duties primarily consist of ensuring there is enough water in tanks to fertilise the crops during the Maha and Yala seasons.
“Other stakeholders may have different objectives centring the tank, but we cannot be compromised by those objectives,” said Gunasekara.
He added that the bunds of certain tanks that vehicles currently travelled on had been repaired and widened to ensure safety.
“This is not such a bund. It is old and we have not investigated the depth in detail; if it breaks, it will be our responsibility. We have no record at all that the bund was checked,” he noted.
Similarly, many of the ancient tanks have not been investigated in depth, according to Gunasekara. The Irrigation Department has records of conducting in-depth investigations for only a few which had broken in the 1950s.
However, Gunasekara said that conducting in-depth investigations routinely was not a necessity.
“We do physical observations and if we observe any issues, we immediately take action. We can do in-depth investigations routinely if we have the staff and if the cost can be borne by the country. It would cost about Rs. 10 million to investigate a tank in such a manner,” he said.
Currently, the department conducts physical observations weekly.
A bund connects two mountains or slopes when a reservoir is being built, forming a ledge of sorts. If a bund is destroyed, it could cause serious harm to people living on either side of the tank as the water would escape.
“If there is a national-level discussion to investigate some reservoirs, then we can give high priority to those to conduct the investigations,” said Gunasekara.
Mahaweli Authority
The Mahaweli Authority conducts in-depth investigations in a similar manner. A top official at the authority said routine internal investigations could be conducted if the necessary funds were available.
“We do monitoring as and when the need arises; for example, if there is mud or if there are cracks, we do further checks,” the official said.
There are about 700 water bodies under the jurisdiction of the Mahaweli Authority of which 33 are major water bodies.
Multiple attempts to contact Irrigation Minister K.D. Lalkantha and Deputy Minister Dr. Susil Ranasinghe proved futile.