Features
Parakrama Samudraya, 1978 flood, and strength of tank bund
By Palitha Manchanayake
Former Irrigation Engineer, Sri Lanka and Hydrologist/Flood Forecaster to the Commonwealth Bureau of Meteorology, Sydney, Australia In this article, the author wishes to highlight his experience during the November 1978 cyclone, while working as an Irrigation Engineer (IE) attached to the Hydrology branch of the Irrigation Department, Sri Lanka.
That particular morning, Tilak Nikapitiya (IE) and I were called in by late Olsen Gunawardane, Senior Deputy Director (Research), to his office and asked us to take a ‘Four-Wheel Drive’ and proceed to Polonnaruwa immediately to meet A.D.S. Gunawardane (IE, Polonnaruwa). We were also expected to rescue and look after the Hydrological Field Unit and the Drilling Team of the Engineering Geology Division who had got marooned in the flood while working in the Maduru Oya area. Before leaving, Gunawardane showed us a photograph that had appeared on page one of the Ceylon Daily News on that day. It had been taken from a helicopter hovering above the Parakrama Samudraya .It showed the flood waves of Parakrama Samudraya overtopping its bund in many places. The Parakrama Samudraya Reservoir was at full capacity, and the water level was quite close to the bund top. Owing to the reservoir’s long fetch of water-spread and the high wind velocities that prevailed during the cyclone, the flood waves generated at the surface were overtopping the reservoir bund.
The author recollects that he had never encountered such a drastic and serious situation during his entire 49-year career as an Irrigation Engineer/Hydrologist. It was an alarming and critical situation considering the danger to the large population living in Polonnaruwa suburbs located below the Parakrama Samudra.
The Parakrama Samudraya Reservoir was built by King Parakramabahu the Great, during his reign (1153-1186 AD) and it has a capacity of 98,000 acre-feet, feeding approximately 18,200 acres of paddy cultivation. This reservoir has a tank bund,which is 52 feet high and nine miles long. When the reservoir is full, the entire nine-mile long bund is tested. It is an earthen dam constructed by the ancient Sri Lankan dam builders about 1,000 years ago.
If an earthen dam is to be built today, one has to follow the principles of soil mechanics, and adhere to the criteria involved in selecting the particular type of soil to be used in construction and the identification of suitable borrow areas for them, and maintaining the required standards of compacting and consolidating the soils. In this process, the mere ramming of soil would not do. It has to be done with the appropriate addition of water so that the maximum soil density is achieved through the optimum soil-moisture content. In the present day, this is achieved by compacting the soil with sheep-foot rollers and performing the ‘in-situ’ soil tests on site. But when the reservoir is on the verge of being overtopped by flood waves, it, in fact, tests the soil mechanics and the compaction techniques adopted using cattle and elephants done in ancient times. If there was a portion of earthen bund of poor quality it could fail and the dam could breach at that point. If this impending dam break happens at an unwanted and unexpected point on the dam, it could be disastrous and devastating, as so many civilians and property downstream of Parakrama Samudra would be seriously affected.
Knowing the imminent catastrophic danger, the Irrigation Engineer (IE) in charge of Polonnaruwa, A.D.S Gunawardane, the Government Agent (GA) Polonnaruwa, Austin Fernando, and a few other officials on duty, decided to get over a few bulldozers and retain them at the sluice and spillway sites, to breach the dam at these points if the need arose. The idea behind it was, if the predicted overnight rainfall occurs and the anticipated inflow to Parakrama Samudra does eventuate, then an artificially introduced breach of the dam at one of these particular outlets would enhance the draining of the floods along the already existing channels, rather than haphazard catastrophic flood damage occurring at an unwanted point over the downstream townships. In doing so, the ‘flood operation team’ would be controlling the flood somewhat, minimising damage to life and property, but the IE would be facing the danger of not being able to continue the issue of water to about 18,000 acres of paddy cultivation which was halfway through the Maha Season. Because of this artificial breaching of the dam, no water would be retained in the reservoir as it would completely empty. As such, it could result in crop failure of a vast acreage, which would be a significant political issue. Farmers who have invested their money in land preparation, seed-paddy, weedicide and pesticides would end up desperate and without any income, possibly creating farmer unrest in the area.
As such, the flood operators were very reluctant to go through with the breaching option unless they were left with no alternative. Yet another unknown factor was how much of the predicted rainfall would occur overnight in the already wet 28 square-mile catchment of Parakrama Samudraya , in addition to whatever inflow that came through Amban Ganga. So, after much deliberation that night, the ‘flood operation team’ decided to stay overnight leaving all sluice and spillway gates open, anticipating the predicted rain to fall over the catchment.
At dawn the following morning, a completely unexpected phenomenon was evident. Even though the reservoir water levels did not overtop the bund and were under control, the anticipated overnight rainfall had not really eventuated, and because the sluice and spillway gates were kept open overnight, the water levels had gone down drastically, causing ‘slip circle failures’ in the dam at many places along the entire stretch of the dam.
Even though there was a 12-foot wide roadway at the crest of the dam, a fair portion of the dam had caved-in with earth slips slumping into the reservoir, leaving only about a four-foot-wide section of the former roadway intact (Figure 2). This could be explained in engineering terms as ‘slip circle failures caused by the sudden drawdown of the water table. The increased pore water pressures of the soil have caused these slips to occur’. It was inevitable, as there were predictions of more overnight rain in the catchment which required due consideration, and there was no way of monitoring the inflow to Parakrama Samudraya at that late hour of the night. This happened in Polonnaruwa, Sri Lanka in November 1978.
The Parakrama Samudraya had to be restored by re-constructing the entire stretch of the damaged bund, which resulted in a major exercise of dam construction. It was re-done with a much broader roadway at the dam crest, and also with big rock boulders in rip-rap to serve as wave-breakers in future.
In this ‘flood operation’ exercise of November 1978, all of 18,200 acres of paddy cultivation was saved, as the Parakrama Samudraya Reservoir was able to issue the required water for the rest of the Maha Season. Luckily, the much-feared disastrous breaching of the bund did not happen. It was indeed a revealing experience for all the Irrigation Engineers of the present day, who manage the ancient reservoirs built by Sri Lankan Kings. On further reflection, one could argue that had we taken the option of artificially breaching the dam bund at a sluice or spill site, we would have overcome the flood dissipating problem easily with a lesser cost of dam construction, but ended up with devastating crop failure of 18,200 acres of paddy cultivation.
What is amazing is that the nine-mile-long earth bund of Parakrama Samudraya stood strong without breaching against the force and the head of water generated by the cyclone, giving full credit to King Parakramabahu the Great and his men.
These were the sort of risks, problems and threats we were faced with when handling the 1978 flood event.
If the eight-foot-wide jogging strip (as proposed in Figure 3) were to be constructed, then it should be at least three feet below the Bund Top Level (B.T.L), in which case a retaining wall of some sort has to be built to ensure the safety of the 16-foot-wide roadway at the top. The construction of this retaining wall could be of concern with the existing structure of the earthen bund.
One case that comes to mind is how late R. Premadasa (then Prime Minister and the Minister of Local Government) around the 1985/86 period, installed a Pumping Station on top of the old Kantale Bund to provide drinking water to the nearby town. After operating the huge pumps for some time, the Bund failed due to the vibrations of continuous pumping. But in the case of the jogging strip at Parakrama Samudraya , one could expect minimal vibrations.
Some point out that no problems have been reported regarding the jogging track at Tissa Wewa in Tissamaharama, built in 2014. At Tissa Wewa, the road is by the side of the lake with a low bund height of about 15 ft. But in the case of Parakrama Samudra, the tank bund is higher, and it is a completely different scenario.
One more important aspect of the new construction that merits discussion is the non-existence of the rip-rap. They say that they are going to roll the big rock boulders downward. The big rock boulders or the rip-rap is actually there to break the waves that occur when the reservoir is operating with water levels above the High Flood Level (H.F.L). The Full Supply Level (F.S.L) generally corresponds to the Full Operating Capacity of the Reservoir. During a special situation, when a flood occurs while the water level remains at F.S.L., the radial gates would be opened. At the point when this flood passes through the spillway system with all its gates open, the extra lift of the water level of the reservoir is called the ‘Flood Lift’. In Sri Lankan reservoirs, the ‘Flood Lift’ is generally calculated for a flood event of 1 in 100-year frequency. This ‘Flood Lift’ is the basis to decide on the H.F.L. of the reservoir. The difference between the H.F.L. and the Bund Top Level (B.T.L) is referred to as the ‘Free Board’ which accounts for the waves that are generated at the surface of the reservoir. The rip-rap which consists of the big boulders is there to break the waves, and it has to be placed between the H.F.L and B.T.L of the reservoir. So, if they are going to roll the big boulders below the H.F.L with the new construction, the purpose would be lost, and if a flood event like the one in 1978 occurs again, there would be one less defence mechanism for wave-breaking, which could be awful.
Therefore, I do not think that it is advisable to do any sort of alteration, meddle with or disturb the good old bund.
(The writer is a former Irrigation Engineer, Sri Lanka and Hydrologist/Flood Forecaster to the Commonwealth Bureau of Meteorology, Sydney, Australia)
Features
Cyclones, greed and philosophy for a new world order
Further to my earlier letter titled, “Psychology of Greed and Philosophy for a New World Order” (The Island 26.11.2025) it may not be far-fetched to say that the cause of the devastating cyclones that hit Sri Lanka and Indonesia last week could be traced back to human greed. Cyclones of this magnitude are said to be unusual in the equatorial region but, according to experts, the raised sea surface temperatures created the conditions for their occurrence. This is directly due to global warming which is caused by excessive emission of Greenhouse gases due to burning of fossil fuels and other activities. These activities cannot be brought under control as the rich, greedy Western powers do not want to abide by the terms and conditions agreed upon at the Paris Agreement of 2015, as was seen at the COP30 meeting in Brazil recently. Is there hope for third world countries? This is why the Global South must develop a New World Order. For this purpose, the proposed contentment/sufficiency philosophy based on morals like dhana, seela, bhavana, may provide the necessary foundation.
Further, such a philosophy need not be parochial and isolationist. It may not be necessary to adopt systems that existed in the past that suited the times but develop a system that would be practical and also pragmatic in the context of the modern world.
It must be reiterated that without controlling the force of collective greed the present destructive socioeconomic system cannot be changed. Hence the need for a philosophy that incorporates the means of controlling greed. Dhana, seela, bhavana may suit Sri Lanka and most of the East which, as mentioned in my earlier letter, share a similar philosophical heritage. The rest of the world also may have to adopt a contentment / sufficiency philosophy with strong and effective tenets that suit their culture, to bring under control the evil of greed. If not, there is no hope for the existence of the world. Global warming will destroy it with cyclones, forest fires, droughts, floods, crop failure and famine.
Leading economists had commented on the damaging effect of greed on the economy while philosophers, ancient as well as modern, had spoken about its degenerating influence on the inborn human morals. Ancient philosophers like Plato, Aristotle, and Epicurus all spoke about greed, viewing it as a destructive force that hindered a good life. They believed greed was rooted in personal immorality and prevented individuals from achieving true happiness by focusing on endless material accumulation rather than the limited wealth needed for natural needs.
Jeffry Sachs argues that greed is a destructive force that undermines social and environmental well-being, citing it as a major driver of climate change and economic inequality, referencing the ideas of Adam Smith, John Maynard Keynes, etc. Joseph Stiglitz, a Nobel Laureate economist, has criticised neoliberal ideology in similar terms.
In my earlier letter, I have discussed how contentment / sufficiency philosophy could effectively transform the socioeconomic system to one that prioritises collective well-being and sufficiency over rampant consumerism and greed, potentially leading to more sustainable economic models.
Obviously, these changes cannot be brought about without a change of attitude, morals and commitment of the rulers and the government. This cannot be achieved without a mass movement; people must realise the need for change. Such a movement would need leadership. In this regard a critical responsibility lies with the educated middle class. It is they who must give leadership to the movement that would have the goal of getting rid of the evil of excessive greed. It is they who must educate the entire nation about the need for these changes.
The middle class would be the vanguard of change. It is the middle class that has the capacity to bring about change. It is the middle class that perform as a vibrant component of the society for political stability. It is the group which supplies political philosophy, ideology, movements, guidance and leaders for the rest of the society. The poor, who are the majority, need the political wisdom and leadership of the middle class.
Further, the middle class is the font of culture, creativity, literature, art and music. Thinkers, writers, artistes, musicians are fostered by the middle class. Cultural activity of the middle class could pervade down to the poor groups and have an effect on their cultural development as well. Similarly, education of a country depends on how educated the middle class is. It is the responsibility of the middle class to provide education to the poor people.
Most importantly, the morals of a society are imbued in the middle class and it is they who foster them. As morals are crucial in the battle against greed, the middle class assume greater credentials to spearhead the movement against greed and bring in sustainable development and growth. Contentment sufficiency philosophy, based on morals, would form the strong foundation necessary for achieving the goal of a new world order. Thus, it is seen that the middle class is eminently suitable to be the vehicle that could adopt and disseminate a contentment/ sufficiency philosophy and lead the movement against the evil neo-liberal system that is destroying the world.
The Global South, which comprises the majority of the world’s poor, may have to realise, before it is too late, that it is they who are the most vulnerable to climate change though they may not be the greatest offenders who cause it. Yet, if they are to survive, they must get together and help each other to achieve self-sufficiency in the essential needs, like food, energy and medicine. Trade must not be via exploitative and weaponised currency but by means of a barter system, based on purchase power parity (PPP). The union of these countries could be an expansion of organisations,like BRICS, ASEAN, SCO, AU, etc., which already have the trade and financial arrangements though in a rudimentary state but with great potential, if only they could sort out their bilateral issues and work towards a Global South which is neither rich nor poor but sufficient, contented and safe, a lesson to the Global North. China, India and South Africa must play the lead role in this venture. They would need the support of a strong philosophy that has the capacity to fight the evil of greed, for they cannot achieve these goals if fettered by greed. The proposed contentment / sufficient philosophy would form a strong philosophical foundation for the Global South, to unite, fight greed and develop a new world order which, above all, will make it safe for life.
by Prof. N. A. de S. Amaratunga
PHD, DSc, DLITT
Features
SINHARAJA: The Living Cathedral of Sri Lanka’s Rainforest Heritage
When Senior biodiversity scientist Vimukthi Weeratunga speaks of Sinharaja, his voice carries the weight of four decades spent beneath its dripping emerald canopy. To him, Sri Lanka’s last great rainforest is not merely a protected area—it is “a cathedral of life,” a sanctuary where evolution whispers through every leaf, stream and shadow.
“Sinharaja is the largest and most precious tropical rainforest we have,” Weeratunga said.
“Sixty to seventy percent of the plants and animals found here exist nowhere else on Earth. This forest is the heart of endemic biodiversity in Sri Lanka.”
A Magnet for the World’s Naturalists
Sinharaja’s allure lies not in charismatic megafauna but in the world of the small and extraordinary—tiny, jewel-toned frogs; iridescent butterflies; shy serpents; and canopy birds whose songs drift like threads of silver through the mist.
“You must walk slowly in Sinharaja,” Weeratunga smiled.
“Its beauty reveals itself only to those who are patient and observant.”
For global travellers fascinated by natural history, Sinharaja remains a top draw. Nearly 90% of nature-focused visitors to Sri Lanka place Sinharaja at the top of their itinerary, generating a deep economic pulse for surrounding communities.
A Forest Etched in History
Centuries before conservationists championed its cause, Sinharaja captured the imagination of explorers and scholars. British and Dutch botanists, venturing into the island’s interior from the 17th century onward, mapped streams, documented rare orchids, and penned some of the earliest scientific records of Sri Lanka’s natural heritage.
These chronicles now form the backbone of our understanding of the island’s unique ecology.
The Great Forest War: Saving Sinharaja
But Sinharaja nearly vanished.
In the 1970s, the government—guided by a timber-driven development mindset—greenlit a Canadian-assisted logging project. Forests around Sinharaja fell first; then, the chainsaws approached the ancient core.
“There was very little scientific data to counter the felling,” Weeratunga recalled.
- Poppie’s shrub frog
- Endemic Scimitar babblers
- Blue Magpie
“But people knew instinctively this was a national treasure.”
The public responded with one of the greatest environmental uprisings in Sri Lankan history. Conservation icons Thilo Hoffmann and Neluwe Gunananda Thera led a national movement. After seven tense years, the new government of 1977 halted the project.
What followed was a scientific renaissance. Leading researchers—including Prof. Savithri Gunathilake and Prof. Nimal Gunathilaka, Prof. Sarath Kottagama, and others—descended into the depths of Sinharaja, documenting every possible facet of its biodiversity.
“Those studies paved the way for Sinharaja to become Sri Lanka’s very first natural World Heritage Site,” Weeratunga noted proudly.
- Vimukthi
- Nadika
- Janaka
A Book Woven From 30 Years of Field Wisdom
For Weeratunga, Sinharaja is more than academic terrain—it is home. Since joining the Forest Department in 1985 as a young researcher, he has trekked, photographed, documented and celebrated its secrets.
Now, decades later, he joins Dr. Thilak Jayaratne, the late Dr. Janaka Gallangoda, and Nadika Hapuarachchi in producing, what he calls, the most comprehensive book ever written on Sinharaja.
“This will be the first major publication on Sinharaja since the early 1980s,” he said.
“It covers ecology, history, flora, fauna—and includes rare photographs taken over nearly 30 years.”
Some images were captured after weeks of waiting. Others after years—like the mysterious mass-flowering episodes where clusters of forest giants bloom in synchrony, or the delicate jewels of the understory: tiny jumping spiders, elusive amphibians, and canopy dwellers glimpsed only once in a lifetime.
The book even includes underwater photography from Sinharaja’s crystal-clear streams—worlds unseen by most visitors.
A Tribute to a Departed Friend
Halfway through the project, tragedy struck: co-author Dr. Janaka Gallangoda passed away.
“We stopped the project for a while,” Weeratunga said quietly.
“But Dr. Thilak Jayaratne reminded us that Janaka lived for this forest. So we completed the book in his memory. One of our authors now watches over Sinharaja from above.”
An Invitation to the Public
A special exhibition, showcasing highlights from the book, will be held on 13–14 December, 2025, in Colombo.
“We cannot show Sinharaja in one gallery,” he laughed.
“But we can show a single drop of its beauty—enough to spark curiosity.”
A Forest That Must Endure
What makes the book special, he emphasises, is its accessibility.
“We wrote it in simple, clear language—no heavy jargon—so that everyone can understand why Sinharaja is irreplaceable,” Weeratunga said.
“If people know its value, they will protect it.”
To him, Sinharaja is more than a rainforest.
It is Sri Lanka’s living heritage.
A sanctuary of evolution.
A sacred, breathing cathedral that must endure for generations to come.
By Ifham Nizam
Features
How Knuckles was sold out
Leaked RTI Files Reveal Conflicting Approvals, Missing Assessments, and Silent Officials
“This Was Not Mismanagement — It Was a Structured Failure”— CEJ’s Dilena Pathragoda
An investigation, backed by newly released Right to Information (RTI) files, exposes a troubling sequence of events in which multiple state agencies appear to have enabled — or quietly tolerated — unauthorised road construction inside the Knuckles Conservation Forest, a UNESCO World Heritage site.
At the centre of the unfolding scandal is a trail of contradictory letters, unexplained delays, unsigned inspection reports, and sudden reversals by key government offices.
“What these documents show is not confusion or oversight. It is a structured failure,” said Dilena Pathragoda, Executive Director of the Centre for Environmental Justice (CEJ), who has been analysing the leaked records.
“Officials knew the legal requirements. They ignored them. They knew the ecological risks. They dismissed them. The evidence points to a deliberate weakening of safeguards meant to protect one of Sri Lanka’s most fragile ecosystems.”
A Paper Trail of Contradictions
RTI disclosures obtained by activists reveal:
Approvals issued before mandatory field inspections were carried out
Three departments claiming they “did not authorise” the same section of the road
A suspiciously backdated letter clearing a segment already under construction
Internal memos flagging “missing evaluation data” that were never addressed
“No-objection” notes do not hold any legal weight for work inside protected areas, experts say.
One senior officer’s signature appears on two letters with opposing conclusions, sent just three weeks apart — a discrepancy that has raised serious questions within the conservation community.
“This is the kind of documentation that usually surfaces only after damage is done,” Pathragoda said. “It shows a chain of administrative behaviour designed to delay scrutiny until the bulldozers moved in.”
The Silence of the Agencies
Perhaps, more alarming is the behaviour of the regulatory bodies.
Multiple departments — including those legally mandated to halt unauthorised work — acknowledged concerns in internal exchanges but issued no public warnings, took no enforcement action, and allowed machinery to continue operating.
“That silence is the real red flag,” Pathragoda noted.
“Silence is rarely accidental in cases like this. Silence protects someone.”
On the Ground: Damage Already Visible
Independent field teams report:
Fresh erosion scars on steep slopes
Sediment-laden water in downstream streams
Disturbed buffer zones
Workers claiming that they were instructed to “complete the section quickly”
Satellite images from the past two months show accelerated clearing around the contested route.
Environmental experts warn that once the hydrology of the Knuckles slopes is altered, the consequences could be irreversible.
CEJ: “Name Every Official Involved”
CEJ is preparing a formal complaint demanding a multi-agency investigation.
Pathragoda insists that responsibility must be traced along the entire chain — from field officers to approving authorities.
“Every signature, every omission, every backdated approval must be examined,” she said.
“If laws were violated, then prosecutions must follow. Not warnings. Not transfers. Prosecutions.”
A Scandal Still Unfolding
More RTI documents are expected to come out next week, including internal audits and communication logs that could deepen the crisis for several agencies.
As the paper trail widens, one thing is increasingly clear: what happened in Knuckles is not an isolated act — it is an institutional failure, executed quietly, and revealed only because citizens insisted on answers.
by Ifham Nizam
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