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Flood protection of Colombo Metropolitan Region-An alternative scheme

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By Dr Janaka Ratnasiri

I thank Eng. Anton Nanayakkara (AN)’s write-up in The Island of 28.07.2020, responding to my article on Flood Protection of Colombo Metropolitan Region which appeared in The Island of 21.07.2020. The main purpose of my article was to highlight the fact that the government after getting Japanese Consultants to formulate a Master Plan for flood protection of Colombo Metro Region at great cost, what is being implemented as a priority project is only a clean-up of the Weras Ganga basin, making a mockery of the word Master Plan. This area is totally outside the Greater Colombo area with no impact on its flooding. AN has failed to comment on this issue.

METRO COLOMBO URBAN DEVELOPMENT

PROJECT

With the failure of the Master Plan to address the flood situation within the city and its suburbs, Sri Lanka Land Development Corporation (SLLDC) has taken the initiative to develop a separate project titled Metro Colombo Urban Development Project (MCUDP) to address this issue. This project expected to be executed during 2012 – 2020 is estimated to cost USD 104 Million (SLLDC Website). It will address flood mitigation in areas covered by the Colombo Municipal Council, Sri Jayewardenapura, Battaramulla, Rajagiriya, Madiwela and Dehiwala. Activities described under “Improvements to existing drainage systems” in my previous article of July 21st were in fact carried out by SLLDC under this project.

COMMENTS ON ENG. NANAYAKKARA’S

RESPONSES

In his response, AN has made certain remarks on some statements appearing in my article and questions their validity. What I have said are totally based on material extracted from other sources including the JICA reports and the website of the SLLDC and not my own suggestions. It appears that AN seems to be unaware of the latest situation in this regard, and hence they need clarification. My comments are given against each of AN’s statements which are given below using material extracted from SLLDC website – Special Projects pages.

1. “The Madiwela East Diversion (MED), remaining dry most of the time, as mentioned, may be due to its wrong location, too far upstream of the Kelani Ganga about 10 miles above the historic Nagalagam Street outfall”.

COMMENT: MED was established by constructing a new canal from the Thalangama Tank up to the origin of the existing natural canal flowing through Malabe paddy fields parallel to Chandrika Kumarathunga Mawatha. It has its natural outfall at Ambatale. The topography of the area does not permit shifting of this outfall further downstream.

2. “Even during floods of the Kelani Ganga, this outfall No 1 (See plan) has to be closed, long before Nagalagam Street outfall closing at +5.00 ft MSL, the accepted minor flood level for Colombo, negating the very purpose for which this canal was built”.

COMMENT: The SLLDC is currently building a pumping station at Ambatale across the MED canal to pump water to the river when its water level rises during heavy rainfall, at a cost of USD 5.85 Million and LKR 1,181 Million (SLLRDC website).

3. “The learned doctor has not noticed the extent to which the Thalangama Tank had silted up, reducing the capacity to retain flood water (about 50 ac.ft) entering the Parliament lake”.

COMMENT: In a project carried out by the SLLDC during 2016 – 2018, the tank was dredged to increase its water holding capacity and remove unnecessary growth on the tank bund, at a cost of LKR 107 million. In any case, I wonder how even a professional hydrologist could notice the extent of silting of the tank just by looking at it.

4. “This gate was constructed at ID’s flood control premises to pump water from the Kelani Ganga to the Beira Lake, for the purpose of cleaning the lake. The project ceased soon after the flood. Strangely, no inquiry was made. It was all swept under the carpet”.

COMMENT: According the SLLDC website, it has built three gates across Kolonnawa Canal, Heen Ela and St. Sebastian canal at the crossing of New Kelani Bridge Road to isolate the canal system enabling water to be pumped back into the canal system from the river by operating the pumps installed at St. Sebastian outfall in the reverse direction. This work to be carried out during 2018 – 2020 is estimated to cost of USD 5.85 million and LKR 1181 million. So, it is not a case of sweeping under the carpet.

5. “Dr. R’s reference to the Beira Lake, too, needs some clarifications. The Beira Lake is not a natural lake. It is an artificial lake also kept at an artificial level, of 6.00 ft above mean sea level, by the Beira Spillway”.

COMMENT: A pumping station is being built across St. Sebastian Canal at Maradana for pumping water from the canal to Beira Lake during periods of high rainfall in Colombo. This work to be carried out during 2019 -2020 is estimated to cost of USD 5.93 million and LKR 165 million. (See also the last paragraph).

6. “Ignoring many other references, contained in Dr R’s article, let me now say a few words about narrowing of bridges, mentioned in it. This is not a matter of life and death, as made out to be. Any hydrologist will agree that within the narrowed section, the velocity will increase to make up for the constriction”.

COMMENT: Widening of the canals and removing bottleneck were not proposals that I made, but what are actually executed by SLLDC as described in its website. Kolonnawa Canal Diversion Stage III says “the canal has become very narrow at certain sections due to encroachment. Some resettlement and land acquisitions are undertaken to remove bottlenecks”. This work to be carried out during 2018-2020 will cost of LKR 1,000 million. Diversion Stage IV also refers to removing two bottlenecks near the outfall.

7. “If, as proposed, the southern diversion takes place, such a canal would become a “trans-basin diversion” let alone the new outfall getting pushed about 20 miles, down south, to Panadura; not to mention reversing the natural flow direction, within the Madiwela catchment, and aggravating the already existing problems, within Bolgoda”.

COMMENT: The proposed diversion is not the first trans-basin diversion in Sri Lanka. Under the Mahaweli Scheme, there are trans-basin diversions. There are even such diversions among ancient works including diversion of Kala Oya to Malwathu Oya basin and Amban Ganga to Yan Oys basin. More recently, Kalu Ganga (Matale) was diverted to Amban Ganga basin under Moragahakanda Project, Uma Oya is being diverted to Kirindi Oya basin. It is also proposed to divert Gin Ganga to Nilwala basin. If Madiwela South diversion is the only practical option available to protect Sri Jayewardenapura area from flooding, it should be pursued after addressing whatever environmental issues that it may cause.

8. “The proposals (which) I have been making for more than 30 years, do not go against nature, no damage to environment by digging new canals, no underground tunnels of large diameter, no widening of bridges, and no pumping”.

COMMENT: If AN’s proposal with no digging of new canals, no tunneling or no widening of canals had merit, why wasn’t it accepted by authorities for implementation all these 30 years?

OPTION WITH NO DIGGING, TUNNELING AND PUMPING

As mentioned in my previous article, the Diyawannawa Lake has two draining outlets, one via Kolonnawa Canal and the other via Wellawatta Canal. The Kolonnawa Canal branches into three canals with outfalls to the Kelani River at Grandpass, Kotuwila and Ambatale which need pumping during heavy rainfall days. Hence, only the Wellawatta Canal is available for draining direct into the sea without resorting to digging new canals, or building tunnels or installing pumping stations. Under the MCUDP project, the stretch of Wellawatta Canal beyond the Galle Road was dredged, widened and the outfall improved at a cost of LKR 111.6 Million. It is to be seen whether this outlet together with the improved outfalls to Kelani River could handle the draining of Diyawannawa Lake during an extreme rainfall event.

ALTERNATIVE PROPOSAL TO DRAIN FLOOD WATER

AN has expressed his reservations about using the Beira Lake as an outfall for flood water as the level of the spillway cannot be adjusted. Though a sum of LKR 1,350 million is spent on building a pumping station at Maradana to divert flood water coming along the Dematagoda Canal into the Beira Lake and then to the sea, there is a doubt as to whether this diversion will work. If it works, it will take flood water from Kotte diverted to St. Sebastian Canal first to the Floating Market and then to the Beira Lake before the water enters the spillway near Galle Face. This will invariably raise the water level of Beira Lake which is presently maintained at 1.8 m above mean sea level to prevent buildings constructed on wooden piles along the lake from collapsing. However, according to an environment screening study on a project for rehabilitation of the Beira Lake carried out by Moratuwa University in 2011, any changes to the water level of the Beira lake can have an adverse effect on the stability of these foundations.

There is however, another alternative option available to improve the draining of Kotte flood water flowing along Dematagoda Canal into the river without posing any of these problems. That is by diverting water flowing in Dematagoda Canal direct into Kiththamphuwa Ela (KE) before it joins with St. Sebastian Canal, by constructing a new canal branching off from the Dematagoda Canal just before it crosses the railway line. This canal could run parallel to the railway line and join with the KE where it makes a U-turn near Welewatta Road. This link canal is only about 0.5 km long and this area comes mostly under railway reservation. The stretch of KE which runs parallel to the railway line up to the river outfall is being widened and dredged under the Kolonnawa Canal Diversion Stage IV at a cost of LKR 1,432 Million. Hence, construction of this new link canal could be undertaken as a part of this project.

The distance to the existing river outfall along St. Sebastian Canal from this branching point is 3.0 km while the distance to the Beira Lake outfall via St. Sebastian Canal in the opposite direction 5.2 km, whereas the distance to the river outfall along the proposed link canal and KE is only 1.7 km. Further, the present St. Sebastian Canal route has six road crossings and several bends while the route via Beira Lake has eight road crossings. Also, the stretch of St. Sebastian Canal behind the Technical College passes through a narrow passage cut through a hill with no room for widening. On the other hand, the proposed route via the link canal and KE is short and straight with only one road crossing at Orugodawatta and is a better option to drain the Kotte flood water into Kelani River, than the proposed scheme via Beira Lake.

CONCLUSION

The SLLDC has already executed several projects worth LKR 1,165 Million with World Bank funding to improve the drainage in several canals in the city and its suburbs. Several more projects estimated to cost over LKR 4,500 Million and USD 44 Million are on-going. This includes a project to take flood water from Kotte all the way to Beira Lake and then to spillway at Galle Face for discharging into the sea by reversing the flow in St. Sebastian Canal. However, this does not appear sensible even to a layman like myself. It is more sensible to drop this proposal and instead develop the link canal to take flood water flowing in Dematagoda Canal direct to KE stretch running parallel to the railway line and thereafter to the Kelani river. The pumping equipment intended for diverting flood water via Beira Lake could be installed at the outfall of KE near Kalu Palama, enabling it to remove the flood water during heavy rainfall.

 



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Features

An air of discontent prevails

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We have had a series of “Avurudhu parties” here in Aotearoa. No shortage of Kavum, Kokis, Athiraha, and even Wali Thalapa. Buffalo curd available locally and of course imported treacle in abundance. Yours truly has assumed the role of a fly on the wall during these festivities and gleaned much information, worth talking about.

First to get on to the Pearl, the talk of the botched-up vaccination plan and running out of the second dose of vaccine. Bizarre permutations as to what would happen if the second dose was not available on time and to who would be press-ganged into getting the “dodgier” types of vaccine from China and Russia, etc. The possible repercussions of getting a second dose of another type of vaccine to the original, the speculations of which left me rather glad that the general populace of Aotearoa has not been vaccinated to date. The talk moved on to the Easter bombings and the recent comments by leaders of the Roman Catholic church as to the possible perpetrators of the attack. Some increasingly obvious conclusions as to those responsible for the planning and funding of same are being reached by those other than some of us who dared to voice our opinions over a year ago! This combined with the increasing and very rapid unpopularity of the person they elected to high office hoping he was genie of the magic lamp type, and the possible reverse of Hong Kong that could take shape on the reclaimed land near the Colombo port, does not bode well for an already dubious future. By reverse of Hong Kong, I mean Hong Kong is trying to hold out as a bastion for democracy, whilst the proposed port city seems to be modeled on the opposite!

Moving on to Aotearoa, the rest of the world seems to be praying for a leader such as our own Jacinda Ardern, but the fat cats of Aotearoa are getting rather sick of her. Those who own multiple houses and have been setting off their interest payments against their taxes due to a loophole in the law that has now been plugged are grumbling. The fact that most young people can’t afford to buy their first houses due to rich people and property developers snapping up all available property, happily funded by banks who are only interested in the bottom line, is of no consequence to them. The fact that this could lead to so much discontent that it could even lead to armed insurrection doesn’t bother them. They seem to have forgotten that we have had almost no deaths and hardly any Covid 19 cases in our community when they say that the lockdowns, we underwent were too excessive and how the economy and business sector has suffered. These very people throng the stadia during the rugby and cricket games and enjoy music concerts with gay abandon. Megacorporations are not happy about the restrictions that are coming on with regard to the use of Liquid Petroleum Gas (LPG) due to environmental concerns. To top it all off I had a lecture from my 13-year-old daughter about how I am being “led by the nose” by Jacinda Ardern and her propaganda! Where she got that from could only be from her elder brothers whose get rich quick schemes have seen a setback due to certain leftist policies coming in from the Labour government that is in power with an absolute majority.

I laugh to myself and think about other examples I have seen of self-proclaimed pundits never being content with their lot. My education was in a very large Government school. As a perfect and a member of some sports teams we handled the administration and some of the governance of this school. Later in life when my children were attending a private school I got involved in the Executive committee of the PTA of that school. The “problems” faced by the private school and the vast dramas that were involved in trying to solve those problems were laughable when compared to those faced by even us, senior students (a much lower level in the administration) of the Government school.

It led me to believe that people always grumble. They are never content with their lot and there is always someone plugging their case and trying to sow the seeds of discontent among the populace. If those living in Aotearoa, in the present situation and well aware of the chaos and mayhem that is prevailing in the rest of the world are dissatisfied, when will anyone be satisfied? Everything is relative and one should try to step outside the confines of one’s own situation and look at the broad picture. In the words of learned barristers, I rest my case!

This week’s missive will not be complete without a tribute to the memory of Prince Phillip, the Duke of Edinburgh. He lived through some of the best and worst times of human existence on this planet and conducted himself impeccably. He showed his humanity and his failings, with a few bloopers down the line but most of those had an undercurrent of humor and couldn’t really be construed as offensive, despite the best efforts of the media and others to make them so. He served as consort to her Majesty the Queen with loyalty and aplomb and he leaves behind an enviable legacy in the world of conservation and youth affairs. It is hoped that his heirs will be up to the task for they face a task which in cricketing terms could be classed as coming into bat after the great Sir Vivian Richards had just scored a century, in his prime. Something very difficult to surpass in skill and entertainment value. Unfortunately, the Duke made just 99. May he rest in peace!

 

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We have much to learn; and emulation is no disgrace

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“Imitation is the sincerest form of flattery that mediocrity can pay to greatness.” said Oscar Wilde who, through sharply ironic wit, often proclaimed the absolute truth.

Cassandra quotes him today as she wants to point out how much we in Sri Lanka can benefit by reaping some ideas from the recent royal funeral in Windsor. And she does not excuse herself for placing stress on our mediocrity as juxtaposed with greatness. Nationalists may shout themselves hoarse and bring down a few more majestic trees by decrying the comparison. They can justifiably claim we have a cultural heritage of two and a half millennia but have we remained cultured, following faithfully and correctly the four great religions of the world? A loud NO from Cass, echoed by millions of others. Though Britain’s development of the English language, culture, arts and science was later than our civilization, they outstripped all countries at one time and are again elevated, while we are poised on bankruptcy, with the begging bowl in hand and thugs and thieves as legislators. We in Sri Lanka are mediocre if not degraded against the greatness shown by the Brits in many spheres. This is no Anglophile speaking but a dame who was born when the Brits were leaving us to govern ourselves and grew up with our statesmen doing a jolly good job of it; Sinhalese, Tamil, Burgher, and a few Muslims taking the lead graciously and effectively with complete honesty, to serve the people. They maintained and improved our country so it was admired by others and even some desiring to imitate Ceylon as Singapore’s Lee Kwan Yew admitted. And where are we now? Except the Rajapaksa family from Medamulana, wearing rose tinted glasses or with eyes shut by arrogance, and their followers and throngs of sycophants, others see our country and our people for what it, and the people, really are. No need to elaborate.

 

The funeral of Prince Philip juxtaposed against customs here

The low-key funeral observing all Covid-19 restrictions was noteworthy for being utterly devoid of bombast and vainglory. It was dignified and moving. Cass wonders how many of her readers watched the funeral on Saturday 17, late evening here. Prince Philip had detailed all arrangements from the Navy being prominent and other Forces joining in plus the substitution of the gun carriage with a jeep he had helped design. The horse carriage he was adept at racing was stationed close by the entrance to the chapel. He has bequeathed it to the daughter of his youngest son and Sophie; the Wessexes having been very close to him and the Queen.

The entire proceedings proved first and foremost that the royal family observed strict pandemic restrictions like mask wearing and physical distancing. There was no one rule for them and another rule for us, thus proving beyond doubt that England (usually), and more so the Royal Family (definitely) are a country and an institution despising double standards. The monarch decreed and abided by the same regulations that have restricted everyone else in the UK, sharing their fate. An anecdote is relevant here. The Queen learned that lesson long ago. She was 14 when her mother said, after Buckingham Palace was bombed in September 1940, that she “could look the East End in the face now.”

Do all our people follow rules common to everyone? Oh! My heavens NO! There are differentiations according to layers in society. Shangri La would host a party for a hundred when only 30 are allowed to gather. During the height of the first wave when restrictions were strict, SLPP electioneering saw hordes thrust together and baby carrying, patting heads and hand clasping mostly by Mahinda Rajapaksha sans a mask. He has a charismatic bond with the masses but that needed to be curbed. Sajith Premadasa’s meetings were strict on physical distancing and mask wearing.

Only 30 were invited to the extremely solemn and yes, beautiful funeral service at Windsor Chapel. This meant eliminating even close relatives of the Family; but it was done. The Queen sat distanced from her daughter and sons and their spouses. Her now diminutive figure seated alone emphasized the loneliness she must be feeling after a close and successful marriage of 73 years.

This brings to mind our First Ladies. Cass steps out bravely to say that Elina Jayewardene was a gracious lady of restraint and dignity, the only perfect consort so far. Cass remembers Hema Premadasa beating her breast (true) and crying over the coffin of her late husband’s remains – in the true sense of the word – at the Prez’s funeral at Independence Square. There is dignity in restraint of even tears over a death in public. Among the women Heads of the country, the mother completely beat the daughter in dignity and ability.

We Sri Lankan women are now much more restrained in our mourning at funerals. Time was when widows even hoarsely wailed their sorrow, coiled and roiled with grief, and begged the dear departed “To look once more; say one word.” Cass in all the expressed grief of such funerals suppressed her laughter with difficulty. How would it be if the corpse obliged?

The choir at the funeral of Prince Philip was just four – one woman and three men. But their singing resounded in the high vaulted, completely majestic, centuries old church. The lone kilted piper within the Chapel evoked much. The service itself was short, just a Reading, prayers and listing of the multitude of honours bestowed on the Duke of Edinburgh, whose medals and decorations were on display beside the alter. The Archbishop of Canterbury, Justin Welby, and the Dean of Windsor, David Conner conducted the service.

To conclude, the Duke of Edinburgh had advised and laid stipulations on a simple funeral with the necessary pomp and pageantry but low key and very unostentatious. The actual funeral was even more low-key with mourners requested not to be on the streets or place flowers. The latter they did in all the residencies of the Royal Family in appreciation of a man who faithfully stood by the Queen and in his own way gave service to the nation.

Coming back to Free Sri Lanka, we seem to stress on that first word Cass inserted to the country name, even in these dire times of no crowds. And the worst is milling crowds are apparently encouraged to boost popularity of certain VVIPs by sycophants and by the preference/orders of the VVIP himself.

Consider the funeral of Minister Thondaman: crowds in Colombo and all VIPs wishing to register their presence before the body, and then the commotion at the actual cremation Up Country. Consider this year’s Sinhala New Year celebrations which were very dignified at the President’s residence but were inclusive of all traditions and a large gathering in the PM’s home, even raban playing by the Second Lady, and milling crowds outside.

 

Roller coaster ride of the country continues

Cass is relieved she had a topic to write on; namely that we should emulate the manner in which the much admired Duke of Edinburgh’s funeral was conducted, abiding by his stricture of it being low key and the country’s Covid restrictions. Our leaders especially must accept the saying I quoted at the beginning.

The country continues its roller coaster bumpy ride with some crying out the country is being sold to the Chinese, we will be a colony of theirs after they occupy the Port City; and others in remote areas sitting down for days on end, some near 100 days, drawing attention to the human elephant conflict. Much is touted about the Bill relating to the rules to govern the Port City.

Cassandra listens to all, and is somewhat warned and frightened, but cannot comment. However, one matter she speaks about loud and clear. The people must be told the status quo of the pandemic – daily numbers catching the infection and numbers dying. This is not for interest sake or ghoulish appetites; but to know how things are so we relax a wee bit or shut in more stringently. The Covid-19 Task Force, or the Health High Ups (not Pavithra please) should tell the country of the true situ of the pandemic as it holds the country in its grip. We want to know whether the grip is tightening or weakening. Please give us daily statistics. This newspaper announces total numbers. No help. Are we expected to jot down figures, subtract, and give ourselves daily infection and death statistics? No! It goes to prove that other matters – political slanted, ego boosting and economics – are more important than warning, containing the pandemic, and saving lives.

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Do you pump Octane 95 Petrol to your car to get better performance?

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If your answer is YES, this article is for you

Dr. Saliya Jayasekara.

Senior Lecturer Department of Mechanical Engineering
University of Moratuwa

Many passenger vehicles, including three-wheelers and motorcycles are fueled by octane 95 gasoline when octane 92 gasoline (petrol) is available at a lower price. 

Otto engine (petrol engine) is an internal combustion spark ignition engine invented by a German engineer Nicolaus Otto in 1876 and used in most of the light weight vehicles including cars, three wheelers and motor bicycles. Otto engines can burn most of the hydrocarbon fuels (including hydrogen and ethanol) that can mix with air by evaporation (low boiling point). But the combustion characteristics of different hydrocarbons are not the same when burned inside an engine. If an Otto engine is designed for a particular fuel, it would not perform similarly with a fuel that has a different chemical composition.

In a well-tuned Otto engine run on gasoline for which the engine is designed, the combustion of the gasoline (petrol) / air mixture will continue smoothly from the spark plug to the piston head by igniting successive layers of the mixture as shown in Figure 1 (a).

If low grade gasolines are used, the combustion of some of the air/ fuel mixture in the cylinder does not result from propagation of the flame front initiated by the spark plug, but one or more pockets of air/fuel mixture explode (Detonate) outside the envelope of the normal combustion front as shown in Figure 1 (b). This detonation can cause severe damage to the piston and the head of the engine while deteriorating thermal performance of the engine (low efficiency)

Gasoline is a petroleum-derived product comprising a mixture of different hydrocarbons ranging from 4 to 12 carbon atoms in a carbon chain with the boiling point ranging of 30–225°C. It is predominantly a mixture of paraffins, naphthenes, aromatics and olefins. Additives and blending agents are added to improve the performance and stability of gasoline. The engine designers learned that straight-chain paraffin have a much higher tendency to detonate than do branched-chain paraffin.

The tendency of a particular gasoline to detonate is expressed by its octane number (ON). Arbitrarily, tri-methyl-pentane, C8H18 (iso-octane) is assigned an ON of 100, while the straight-chain paraffin n-heptane, C7H16 is given an ON of zero. Hence, a fuel sample with the same anti-detonation quality as that of a mixture containing 90% iso-octane and 10% n-heptane is said to have an ON of 90. Gasoline is made up of a mixture of mostly branched-chain paraffin with suitable additives to give an ON in the range 90 –100. It was also learned through experiments that the ON of a gasoline blends (e.g. gasoline and ethanol) can be calculated by using weighted average ON of each compound. Most importantly, the octane number has nothing to do with the heating value (Calorific value) or the purity of the fuel.

Engine thermodynamics show that engines with a high compression ratio offer higher thermal performance than engines with a low compression ratio. These engines having high compression ratio require high octane gasoline (for example octane 95) to avoid detonation. However, using gasoline having higher octane ratings for the engines designed for a low octane rating (for example, 92 octane) would not provide an additional benefit or loss, other than increased fuel cost.

Therefore, it is important to know the designed octane number of the engine before fueling (refer owner’s manual of the vehicle). For example: the minimum ON requirement for two and three wheelers in south Asia is 87 (The World Bank). Most of the Toyota, Honda and Nissan models including hybrid engines recommend 92 octane gasoline.

Dr. Saliya Jayasekara received the B. Sc. degree in mechanical engineering from university of Moratuwa in 2001, and the M.Sc. and PhD degrees in decentralized power generation systems from Royal institute of technology Sweden and the Melbourne University Australia in 2004 and 2013 respectively. He has well over 13 years of national and international experience in design and installation of centralised/decentralised power plants, boilers (utility/package) and heat exchangers. Currently he is serving as a senior lecture at University of Moratuwa, a visiting lecturer and fellow at Deakin University Australia.

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