Connect with us

Opinion

Save Parakrama Samudraya!

Published

on

By Bandula Kendaragama, Dam Safety Consultant, Melbourne, Australia

This article is written based on information collated through consultations that were submitted as a technical report recently to President Gotabaya Rajapaksa and other relevant government authorities. The consultations were among those who had been interested in dam safety and directly involved in managing the “Narrowly-Missed” breach and in the reconstruction of the Parakrama Samudraya bund after the Cyclone in 1978. They considered it appropriate in sharing concerns and acquired knowledge with the public at this crucial juncture of decision-making on the safety of the aging irrigation infrastructures in Sri Lanka.

The Parakrama Samudraya Reservoir was built by King Parakramabahu the Great, during his reign (1153-1186 AD) and it has a reservoir capacity of 116,000 acre-feet, feeding approximately 25,000 acres of paddy cultivation. This reservoir has a bund 52 feet high and 10 miles long.

The study on the Parakrama Samudraya bund was undertaken owing to information and misinformation that had been widely shared and debated in the formal media, and especially in the social media, concerning the Parakrama Samudraya bund being proposed as a site to construct an 8-feet wide walking path. Further, it is noted that similar walking paths will be constructed on bunds of other reservoirs such as Kantale, Udukirala Wewa, etc.,

Cyclone in 1978

The 1978 Cyclone started with the onset of the storm formed on 20 November 1978 over the southwest Bay of Bengal. It intensified gradually, reaching Super Cyclonic Storm Status Category 4 Cyclone on 23 November with a gusty wind speed of 220 kmph. The 1978 Cyclone was the second strongest Super Cyclonic Storm to strike Sri Lanka’s Eastern Province since modern records began. The cyclone attained peak intensity on November 23, before making landfall in Batticaloa. The Eastern Province was heavily affected by the cyclone.

The cyclone had devastating impacts in Sri Lanka, killing about 915 people and an unaccounted number of cattle and other animals. An estimated more than one million people were affected, with over 250,000 buildings damaged, and one-fifth of Batticaloa’s fishing fleet destroyed. Nine of the 11 paddy stores were destroyed and 90 % of the coconut plantation (about 28,000 acres) in the Batticaloa district were destroyed. Also, in Polonnaruwa District, the public and private infrastructure, paddy, and rice stored in Food Commissioners and Cooperatives, coconut cultivation, etc., were devastated.

Cyclone 1978 and Parakrama Samudraya

The Cyclone reached the Parakrama Samudraya bund at about 6:30 pm on 23 November and lasted till about 4:00 am on 24 November. According to eyewitnesses, the height of the waves was 10 to 12 feet. Knowing the imminent catastrophic danger of overtopping leading to a breach of the bund, the Irrigation Engineer in charge of Polonnaruwa A. D. S. Gunawardana, the Government Agent Polonnaruwa Austin Fernando, and a few other officials, on duty, decided to be ready with a few bulldozers and retain them standby at strategic locations such as at the sluice and spillway, to breach the bund at these locations if the need arises.

The idea behind this decision was if the predicted overnight rainfall occurred and the anticipated inflow to the Parakrama Samudraya did really eventuate, the inflow would have been greater than the outflow with all 10 radial gates and the sluice gates kept open. Then there was a risk of overtopping and breaching the bund. Hence, an artificially introduced breach of the bund to discharge floods along the existing channels would prevent a haphazard catastrophic breach at an unknown and unwanted location, which could inundate the heavily populated downstream areas. Such an emergency rapid drawdown is the standard practice to prevent a dam breach. Fortunately, predicted overnight rainfall was low. However, the drawdown of the reservoir continued overnight.

Following the overnight drawdown, about 2/3 of the 12-feet wide bund top road and a fair portion of the upstream shoulder were found to be slipped into the reservoir, leaving only about 1/3 of the bund top road intact. There were widespread such slips along the full length of the bund. The damaged areas were repaired with earthfill and Ralapanawa reinstated as a short-term risk reduction measure. The upstream face of the Ralapanawa was not flattened to improve the safety margin (i.e., Factor of Safety) of the bund in case of future similar drawdowns as it was a long-term risk reduction measure to be implemented by the Government Authorities. Therefore, consideration should be given to implementing appropriate long-term risk reduction measures.

Walking Track Proposal

Based on information available to date, the proposed walking path will be constructed on the upstream side of the bitumen surfaced bund top road where there was a sliding failure during the 1978 cyclone and floods (See Figure above 1).

Several long tension cracks, sealed with tar, are present on the bitumen surfaced bund top road as seen in videos of Sri Lanka media. Most of them are located along (parallel) the bund top road, thus increasing the risk of sliding failures similar to those that occurred during the 1978 floods. Additional loads due to the construction of a walking path would widen and deepen those tension cracks, compromising the safety of the bund, which is not known.

Therefore, it is the considered view that additional loading on top of the 1978 sliding mass for construction of the walking path would increase the risk of reactivating the 1978 slides during a future rapid drawdown, similar to in 1978.

It is understood and appreciated that the Irrigation Department is currently undertaking geotechnical investigations to assess the safety margin of the bund.

The highest concern is dam-safety

Based on information available, it is understood that there is a period of 741-years (i.e., from 1159 to 1900), where the performance of the bund is not documented and unknown. However, it is reported that the bund was totally breached during the colonial era. According to R L Brohier, the bund and the reservoir were abandoned for more than a century.

Given that the population at risk in case of a dam break is extremely high, it appears that the consequence category of this bund is “Extreme” as per the current international dam safety guidelines. Therefore, the proposed walking path at Parakrama Samudraya cannot be compared to that of the Kurunegala Wewa, Boralesgamuwa Lake, etc., constructed along the reservoir rim, and the walking paths constructed around water bodies in the suburbs of Colombo.

It is understood that the Parakrama Samudraya is formed by combining three reservoirs of unknown history. Therefore, the bund may have been raised in several stages during the 741-years associated with unknown performance. It is not known whether dam safety-related defects of the bund such as slips or slides, cracks, animal burrows, sinkholes, soft areas, root bowls, zones of desiccation cracking, zones of residual shear strength because of historical failures, etc., were repaired to satisfactory standards, or not.

The aging of dams constructed of earth and rockfill material is due to time-related changes in the properties of the materials of the structure and its foundation. As reported in a technical paper published in May 2010 by the United States Society of Dams, the aging or deterioration of embankment dams and their foundations are of concern. These concerns extend throughout the entire life of the dam until safe abandonment or demolition.

Recent interventions on dam-safety

Given the dam safety issues associated with this controversial walking path project, the Water Forum of the Institute of Engineers in Sri Lanka conducted a Webinar on 09 September 2021 on “Usage of Inland Water Bodies for Recreation”. More than 280 personnel, mainly engineers, participated in this Webinar and raised over 100 questions related to the safety of the bund. Several questions were raised on fundamental errors and potential failure modes associated with the proposed walking path. It appears that ad hoc decisions have been taken for reasons unknown. The lack of laws and dam safety regulations in Sri Lanka could be one of the reasons for such ad hoc decisions taken by various individuals and organisations.

As far as dam safety regulations are concerned, India is well ahead of Sri Lanka. Even Ghana in Africa has introduced Dam Safety Regulations to ensure the safe design, construction, operation, and maintenance as well as decommissioning of dams.

Based on statistics of embankment dam failures and accidents, 48% of dam failures are related to overtopping and failures of appurtenant structures, and 46.5% are due to internal erosion. Due to the absence of an internal filter system in this bund, not only the slope instability, but the internal erosion is also likely to be a prominent potential failure mode.

It is understood that planning is underway to construct several fast-food outlets, toilet facilities (including a “changing room”) at the toe of the bund, i.e., within the reservation area of the bund located immediately downstream of it. It is to be stressed that this stretch of land along the bund is a critical area to ensure the safety of the bund. Identification of dam safety features such as heaving the ground, cracks, wet areas, springs, seepage locations, etc., in this area, is critical. Digging of lavatory pits, trenches, etc., could intercept permeable layers in the foundation and may trigger “backward erosion tunnels” leading to piping, which is a major failure mode in embankment dams (or, bunds). Excavations in this area could lead to sides of the downstream face of the bund, compromising its safety margin.

Should there be a need to improve the safety margin of the bund, additional stabilizing fills are to be constructed in this area over the downstream face of the existing bund. An access road along the downstream toe of the bund is an essential item for repairs and routine maintenance of the bund. Given the proximity to the dam, this reservation area should be used to stockpile materials to be used during dam emergencies such as filter sand, crushed rock, rockfill, etc., and movement of construction machinery for maintenance and repairs. This area is an integral part of the bund, hence should not be used for either permanent or temporary constructions. Therefore, consideration should be given to providing these facilities at an alternate suitable location, perhaps close to the Government Agent’s residence, or thereabouts.

Recommendations to maintain dam safety

Based on dam safety concerns and consequences discussed, it is recommended that,

1) the crest of the bund is reserved for routine maintenance, including replacement of displaced Ralapanawa if necessary, placement of additional boulders if required, and for construction of temporary overtopping protection bund using ‘Sandbags”, as and when required.

2) the stretch between the Ralapanawa and bitumen road be reserved for the construction of a wave wall to meet the dam safety requirements of future hydrological reviews to be undertaken during the service life of the reservoir and bund.

3) a safe “Load Capacity” be imposed on the bund top road, and arrangements are made to stop all heavy trucks plying on the bund top road as the bund has not been designed for such traffic loads.

4) the bund top road is completely closed for all traffic, say from 5:30 am to 7:30 am and then from 6:00 pm to 9:00 pm or as agreed by local authorities, in the preferred 2km long stretch, and then the existing bitumen surfaced bund top road to be used as the walking path (Alternatively, only the upstream-half of the bitumen surfaced bund top road to be used as the walking path while the downstream-half of the bitumen surfaced bund top road to be kept open for one-way light traffic only, subject to nominated maximum speed to ensure the safety of people using the walking path).

5) an alternative walking path (For example, in the reservoir rim), be investigated which will not compromise the safety of the dam.

6) the reservation area located immediately downstream of the bund is not used for developments that are been planned by the Urban Development Authority as this area is very sensitive to dam safety issues.

7) the reservation area located immediately downstream of the bund, which is an integral component of the dam, be a property of the Irrigation Department for inspection and monitoring of critical dam safety features, construction of a toe access road, construction of stabilizing fills if required, stockpiling of construction materials required during dam emergencies, etc.,

8) a potential failure modes analysis and Risk Assessment be undertaken in accordance with international dam safety standards.

9) a Design and Safety Review of the dam and appurtenant structures be undertaken in accordance with the international dam safety standards incorporating review of geotechnical parameters of the bund and foundation, hydrology, wave run-up, seismicity, flood handling capacity, reliability of gates and instrumentation, etc.,

10) sufficient funds must be allocated to undertake Design and Safety Reviews of all “Extreme” consequence category dams in Sri Lanka.

11) sufficient funds must be allocated to routine maintenance of dams (Note: Depending on their nature, some maintenance items, if not addressed in a systematic and timely manner, may eventually become dam safety issues, eventually leading to failure of dams).

12) early arrangements must be made to implement the recommendations of the Cabinet Memorandum No. 11-2020 dated 26 October 2020 on the Establishment of a Dam Safety Consultation Centre and a Dam Safety Regulatory Mechanism.

(The author can be contacted on email: bandula.kendaragama@gmail.com)



Continue Reading
Click to comment

Leave a Reply

Your email address will not be published. Required fields are marked *

Opinion

The passing away of a great cellist

Published

on

Rohan de Seram

by Satyajith Andradi

The Oxford Dictionary of Music compiled by Michael Kennedy is an invaluable source of reference material on the whole gamut of western classical music. Its 1994 second edition has the following entry on Rohan De Saram, in its usual telegraphic language : “De Saram, Rohan ( b Sheffield, 1939 ). Sri Lankan cellist. Studied in Florence with Cassado and later with Casals in Puerto Rico. After European recitals made Amer. Debut in NY, 1960. Settled in Eng. 1972, joining teaching staff of TCL. Wide repertory from Haydn to Xenakis, specializing in contemp. works. Cellist of *Arditti String Quartet.” Rohan De Saram is certainly one of the greatest musicians Sri Lanka has ever produced. He passed away in the UK on 29th September 2024 at the age of 85.

I had the good fortune to see this great musician perform in two occasions. The first was way back in 1975, when my parents took me to see his cello recital, which was given at the newly opened BMICH on 16th August that year. The second was when I took my daughter to his concert at the British Council auditorium on 27th February 2007. There was a marked difference in the type of music he performed at the two recitals. The 1975 programme was dominated by the music of Rachmaninov, Schubert, and Shostakovich, with the first movement of Zoltan Kodaly’s Sonata for Solo Cello added as a sort of outlier. It belonged to the traditional western music repertoire, if you like. In contrast, the 2007 concert was dominated by more contemporary music, although it included pieces by Bach, Beethoven, Rimsky Korsakov, Gabriel Faure, Saint Sean, and Benjamin Britten. The highlights of the evening were Luciano Berio’s Sequenza 14 for solo cello, a through and through avant garde work, and the last two movements of Kodaly’s Sonata for Solo Cello. Needless to say, the two programmes reflected the tremendous change in Rohan De Saram’s artistic orientation from being a performer of classics to that of avant garde music by composers such as Iannis Xenakis and Luciano Berio.

Rohan De Saram was born in the UK on 9th March 1939. He belonged to a well-to-do cultured family. Due to the outbreak of the Second World War, he had to spend much of his early childhood in Sri Lanka. As he showed a special gift for cello playing, he was taken to Europe for his musical education. Initially he studied cello under the renowned Spanish cellist and composer Gaspar Cassado in Florence, Italy. His first appearance as a soloist at the Royal Festival Hall in London was at the age of sixteen. This was followed by performances as soloist at London’s Wigmore Hall and Royal Albert Hall. Winning the Guilhermina Suggia award, enabled him to take master classes from the great Spanish cellist and composer Pablo Casals, who wrote of him: “There are few of his generation who have such gifts” and ” Rohan is already a remarkable cellist of fine technique and musical taste. I can predict for him a brilliant career.”

Casals’ prophesies were to come true. Rohan De Saram had his Carnegie Hall debut at the age of 20. He went on to perform as a soloist with many of the world’s leading orchestras such as the London Symphony Orchestra, the London Philharmonic Orchestra, the Royal Philharmonic Orchestra, and the New York Philharmonic Orchestra under the leadership of renowned conductors such as Adrian Boult, Malcolm Sargent, John Barbirolli, Colin Davis, and Zubin Mehta. During this early period of his career, he was essentially a virtuoso performer of the classics. However, joining the Arditti Quartet in he late 70s as its cellist signaled a turning point in his musical orientations. This quartet specialized in contemporary avant garde music. Henceforth, the main focus of Rohan De saram was on the works of avant garde composers such as Iannis Xenakis and Luciano Berio. He was a member of the Arditti Quartet from 1979 to 2005. As a virtuoso cellist of international renown, he introduced contemporary music to numerous musical audiences throughout the world. His passing away leaves a void in the musical firmament.

Continue Reading

Opinion

UK’s deal with Mauritius will be a win for all

Published

on

Location of the Chagos archipelago (circled) Wikipedia

Freedom for Chagos islands:

by Peter Harris
Associate Professor of Political Science,
Colorado State University

Britain is close to resolving its territorial dispute with Mauritius over the Chagos Archipelago, located in the central Indian Ocean.

For years, Mauritius has claimed the island group as part of its sovereign territory. It says that Britain unlawfully detached the islands from Mauritius in 1965, three years before Mauritius gained independence. The Mauritian position is backed by international courts and the United Nations, creating enormous pressure for Britain to decolonise.

London, however, has been reluctant to abandon the Chagos Archipelago. This is because the largest island, Diego Garcia, is the site of a strategically important US military base. Britain pledged to make Diego Garcia available to its American ally and has been anxious to avoid a situation where it is prevented from making good on these promises.

The US, for its part, has declined to become publicly involved in the dispute. Its private position is merely that the base on Diego Garcia should not be placed in jeopardy.

In a deal announced in a joint statement, London and Port Louis have agreed that all but one of the Chagos Islands will be returned to Mauritian control as soon as a treaty can be finalised. This comes after nearly two years of intense negotiations. It seems as though settling the dispute was a top priority for Britian’s new Labour government.

Though the deal isn’t done yet, it is expected to go through. Both Britain and Mauritius, along with the White House, have endorsed the agreement, indicating that the toughest negotiations are complete.

Diego Garcia will remain under British administration for at least 99 years – this time with the blessing of Mauritius – enabling Britain to continue furnishing the US with unfettered access to its military base on the island.

In exchange for permission to continue on Diego Garcia, Britain will provide “a package of financial support” to Mauritius. The exact sums of money have not been disclosed but will include an annual payment from London to Port Louis. Both sides will cooperate on environmental conservation, issues relating to maritime security, and the welfare of the indigenous Chagossian people – including the limited resettlement of Chagossians onto the outer Chagos Islands under Mauritian supervision.

I’ve studied the Chagos Islands for 15 years, first as a master’s student and now as a professor. It often looked as though this day would never come.

The deal that’s been announced is a good one – a rare “win-win-win-win” moment in international relations, with all the relevant actors able to claim a meaningful victory: Britain, Mauritius, the US, and the Chagossians.

Win for Britain

Britain went into these negotiations with one goal in mind: to bring itself into alignment with international law.

London suffered humiliating setbacks at the permanent court of arbitration in 2015, concerning the legality of its Chagos marine protected area; at the International Court of Justice in 2019, when the World Court found that Mauritius was sovereign over the archipelago; and at the UN general assembly that same year, when a whopping 116 governments called on Britain to exit the Chagos Islands.

Mauritian sovereignty over the Chagos group had even begun to be inscribed into international case law.

London could probably have defied international opinion if it had wanted to. Nobody would have forced Britain to halt its illegal occupation of the Chagos Archipelago. But such a course would have badly undermined Britain’s global reputation and its ability to criticise others for breaches of international law.

This agreement will give Britain exactly what it wanted: a continued presence on Diego Garcia that conforms with international law.

Win for Mauritius

Mauritius, of course, went into these negotiations intent on securing full decolonisation at long last. Britain and the US now recognise that the Chagos Archipelago belongs to Mauritius.

Mauritius will not have day-to-day control of Diego Garcia, but it will be acknowledged as being sovereign there. The public description of the agreement also doesn’t seem to prohibit Mauritius from exercising its sovereignty over Diego Garcia as it relates to non-military domains.

Win for the US

The US is another clear winner from the deal. In fact, hardly anything will change for America. Washington will continue working closely with London, and will not need to negotiate an agreement with Mauritius on its rights to the base or the status of forces.

Indeed, Pentagon officials should be thrilled that their base on Diego Garcia has been put on firm legal footing. This is something that Britain alone was unable to offer. The bilateral agreement with Mauritius will ensure the security of the base for 99 years – no small feat.

Good for Chagos Islanders

Finally, the deal is good for the Chagos Islanders.

British agents forcibly depopulated the entire Chagos group between 1965 and 1973. The point was to rid the archipelago of its permanent population so that the US base on Diego Garcia would operate far from prying eyes. Britain deported the Chagossians to Mauritius and the Seychelles, which is where most Chagossians and their descendants still live. Some have migrated onwards, including to Britain.

Britain had long opposed the resettlement of the Chagos group by the exiled Chagossians. Mauritius, on the other hand, has indicated its openness to resettlement of the Outer Chagos Islands – so, not Diego Garcia – something that Port Louis is now free to pursue.

Not all islanders have welcomed news of an agreement. The Chagossians are a large and diverse group, with differing views about how their homeland should be governed. Some would have preferred Britain to administer the entire archipelago long into the future, feeling that Mauritius was an unwelcoming host to the exiled Chagossians. But Britain could not hold onto the Chagos Islands forever – at least, not lawfully.

For their part, the largest Chagossian organisations are content with the deal as it has been announced, and will now work with Mauritius on a resettlement plan.

The critics

This is the first instance of decolonisation that London has attempted since returning Hong Kong to China in 1997. Predictably, some in Britain are opposed to the settlement.

Some accuse the Keith Starmer government of “giving up” the Chagos Archipelago. But the islands were never Britain’s to give up – they were always Mauritian sovereign territory, and Britain was an unlawful occupier.

They are also wrong to blame this deal for jeopardising the base on Diego Garcia. The opposite is true: for better or worse, the agreement will resolve any uncertainty about the US base’s future. It will have total legal security.

Finally, critics are grasping at straws when they raise the prospect of Mauritius permitting a Chinese base in the Chagos Archipelago. This is a baseless smear. There is no indication whatsoever that Port Louis has any interest in hosting the Chinese military.

What happens now?

Britain and Mauritius still need to reveal the text of their bilateral treaty. But the deal is highly unlikely to fall through. Both governments, plus the White House, have welcomed the agreement – a sure sign that the hard work of negotiations is over.

All that remains is for the treaty to be ratified – a process that does not require a parliamentary vote in the House of Commons. There is no reason why this cannot be done quickly.

This could be the end of a shameful saga that went on for too long.

(Courtesy of The Conversation.)

Continue Reading

Opinion

Dr P R (Ranji) WIKRAMANAYAKE (17 01. 1932 – 30.07.2024)

Published

on

A few weeks ago, the Sri Lankan community in Australia lost one its most distinguished sons, Dr P R Wkiramanayake, known as Ranji to his friends, an accomplished and highly regarded endocrinologist. He was 92 years of age and hailed from a distinguished family with its origins in Galle. The ancestry and genealogy of the family is well recorded in the book “Galle as quiet as asleep “(1993) by Norah Roberts.

The elder son of E.G. Wikramanayake, Queens Counsel, Ranji was born into the lap of luxury. Like his father before him, Ranji attended St Thomas College, Mount Lavinia from where he entered the Ceylon Medical School, and from where he graduated, and proceeded to the UK for Post graduate work. On his return from London with the MRCP he was appointed consultant physician at the Out Patients Department of the General Hospital, Colombo.

He soon was interested in the study of diabetes and read a paper at the Plenary Scientific Sessions of the Ceylon college of Physicians, 30 years ago. After serving a Nuffield Fellowship in the UK, he moved to Australia where he worked as Diabetologist at the Prince Edward Hospital.

It was through my close friend and former schoolmate Dr Medduma Kappagoda that I first met Ranji who Kappa brought home one day about 30 years ago, in order to assess my blood sugar. That visit was the foundation on which a strong friendship developed and through which I had the great pleasure of enjoying a dear friendship with his brother Nimal later after I moved to Melbourne.

Ranji lived in the affluent and desirable seaside suburb of Vaucluse and his great hobby was horse racing. His father Guy, a leading Queens Counsel, had owned a string of racehorses in Colombo and was the winner of several trophies when racing was the pastime of “kings and squires”. Ranji too owned at least a couple of thoroughbreds in Sydney whose activities kept him occupied during his leisure.

Ranji married Amara Weerasooria daughter of the late Dr and Mrs SE Weerasooria. Amara was Head Girl of Visakha Vidyalaya and an outstanding netball and tennis player. There combined qualities had to produce extra ordinary children. Their only son Priyan is a popular gastro surgeon in. Bowral, and the two daughters Roshanara a lawyer and Shemara is a highly successful leader in the corporate world of Australia.

It was during the course of last year, and earlier this year that I had close interaction with Ranji. It was during this period that Nimal fell ill and passed away about three months ago. Ranji was highly solicitous of Nimal’s welfare, and chose to convey his medical advice to Nimal through me. Ranji the elder brother was generally of a quiet and unruffled disposition. When Nimal was hospitalized he chose not to disturb him, and instead telephoned me for progress reports. About six weeks ago he rang me from his hospital bed in Prince Edward Hospital where he worked previously, to say in a feeble voice that his heart is failing on him. He left this world a few days later.

Ranji Wikramanayake was of a rare breed, sadly lacking in the old country today. Dedicated to his profession, and guide and guardian to his family, he was honest, hardworking and generous. He was a founder member of the. Ceylon College of Physicians, and a member of the Ceylon Society of Australia for many years until his demise.

A little known aspect of his generosity was his donation of five million rupees in January 2016

to the Ceylon College of Physicians, the interest earned from the donation to be awarded annually to the best research paper on diabetes. Ranji was to personally present the donation, but on their way to Colombo, his wife Amara fell ill and had to return to Australia. He was not a man for excuses and made sure that the gift was made on his behalf by his close friend Tilak de Zoysa. Ranji Wikramanayake certainly earned his rest, may he now rest in peace.

Hugh Karunanayake

Continue Reading

Trending