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Solution to water deficit in NWP and NCP

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by BANDULA KENDARAGAMA

Former Section Engineer (Dam), Kothmale Hydro-Power Project and International Dams Consultant, Melbourne, Australia

(Based on an interview with Srilal D. Perera (Construction Project Manager), Melbourne, Australia)

Sri Lanka is now a middle-income country with consistently high economic growth over the recent years. The government’s public investment plans include several development plans and projects for the coming years, to further accelerate economic growth and promote social and human development.

Being a tropical island located close to the equator, Sri Lanka is highly susceptible to adverse effects of climate change. The Global Climate Risk Index (CRI) 2018, which indicates how countries have been affected by the impacts of weather-related loss events (storms, floods, earthquakes, heat waves etc.,) ranks Sri Lanka as the fourth among the most affected countries of the world. This is an alarming situation. Adverse effects of climate change are evident from the severe and long duration droughts as well as severe flooding occurring almost every year in several parts of the country. Water availability is becoming more variable and uncertain, even as demand for bulk water supplies for agriculture, new industries and tourism and clean water for drinking increases. Studies confirm that these impacts are likely to exacerbate, and the wetter areas of the country would eventually become wetter, and the drier areas drier and drier.

The government of Sri Lanka has taken steps to address these challenges with the successful completion and commissioning of Moragahakanda and Kalu Ganga reservoirs, and the ongoing and planned construction of dams and associated feeder canals, hydraulic facilities, Hydro Power enhancements to comply with Paris Convention that His Excellency the President of Sri Lanka has consented under renewable energy promotion in Sri Lanka; as well as, other water resources development investments envisaged under the Public Investment Plan (PIP). The Government is also implementing several other programs and investments to mitigate flooding and flood damages in several river basins which are vulnerable to flooding.

Planning and investments in additional water storages, and transfer infrastructure to transfer water from water surplus river basins of the wet zone to water deficit river basins, will be a major priority to meet the growing demands and challenges of climate change impacts. Additional investments will be required on a priority basis for developing water resources to provide potable water supplies to people and areas currently affected by chronic kidney disease.

These new investments on water resources will demand diligent planning, protection, management and allocation of water for multiple uses and users within river basin context. As the water infrastructure expands through additional infrastructure bringing water to water deficit geographic areas, to new and current groups of farmers, large and small industries, urban and rural drinking water consumers, mechanisms will be required for diligent planning, allocation, and monitoring of bulk water supplies from the major water conveyance systems beyond the mandate and the role played by the existing Water Management Secretariat (WMS) of the Mahaweli Authority of Sri Lanka (MASL).

 

The Project

With the present climatic uncertainty, North Western Province (NWP) and the North Central Province (NCP) are among the most affected areas without reliable supply of water for irrigation, about 40,000 ha, and ensuring domestic water supply to families in such provinces. Major diversions of this water are supplied through the Polgolla tunnel (875 Million Cubic Meters (MCM) / Year) for both the seasons of Yala and Maha. This volume of diversion is entirely depending on the storage above the Polgolla barrage. At present only the Kotmale reservoir with 174 MCM supports to regulate this water. However, the Polgolla tunnel is functioned only with 60% of its capacity, and the tunnel has additional capacity to divert around 400 MCM / Year, if the upstream storage is available.

Therefore, a proposal for increasing the height of the Kotmale dam to increase the retention capacity by additional 250 MCM would be one of the feasible proposals to solve the water deficits in NWP and NCP. Also, the increased head and volume would boost the hydro-power generation by about 20%, once the supplementary water starts to pass through Kotmale and Ukuwela power stations.

The Kotmale Hydropower Project was one of the first projects taken up under the Accelerated Mahaweli Development Program (AMDP). It was the most upstream among those headworks in the Mahaweli river basin, and exploited the hydropower potential of Kotmale Oya, a major right bank tributary of the Mahaweli Ganga. The Kotmale dam site is at Kadadora, located about 6.6km upstream of the confluence of Kotmale Oya with Mahaweli Ganga, where the river forms a narrow and deep valley with steep banks. The powerhouse is underground and situated in the belly of the Atabage mountains, about 6.4km downstream of the Kotmale Oya – Mahaweli Ganga confluence.

The basic elements of the Kotmale Hydro-Power Project are a concrete face rockfill dam (87m high and 600m long) having the active storage capacity of 174 MCM and a tunnel system leading to 201MW power plants with outfall to the Mahaweli Ganga. The primary function is the generation of electric power. Additional benefits arise from an increase in the amount of irrigation water available at the Polgolla diversion, as well as mitigation of floods in the Gampola area as a result of the regulation of flows in the Kotmale Oya. The Project construction work commenced in 1979 and was completed in 1985, with financial assistance provided by the Government of Sweden.

The dam has been provided with basic facilities for future rising, to three alternative levels 715m, 725m and to 735m above the sea level (capacity of 370 MCM at 728m FSL). The provision for the extension of foundation from the downstream face, and the land around the reservoir rim up to 735 m elevation, have already been acquired since the beginning to enable the future upgrading.

However, the raising of Kotmale dam would be an engineering challenge and need in depth study to check the stability of the Concrete Face Rockfill Dam (CFRD), during and after construction, instrumentation, reliability of foundation and geology, supplementary grout curtain, spill gates and chute with elevated ogee (Flip bucket), added pressure head to tunnels, height of the surge shaft and power station equipment etc., Also, the heightening of the dam shall not affect the ongoing annual supply of water to NCP, as it would generate critical social problems and, therefore, the live construction method statement with the active storage of water available for downstream use would be the most practical approach.

Therefore, a comprehensive feasibility study shall be originated to find a solution for the critical water deficit in NWP and NCP, and for harnessing addition of renewable energy, considering above referred to facts at earliest possible.

The original consultant of this project was Sir William Halcrow & Partners (Halcrow Water) of the United Kingdom (UK); and Skanska (Sweden) with joint collaboration of Central Engineering Consultancy Bureau (CECB) , then local Consultant to the Mahaweli Ministry, had been involved in a preliminary feasibility study, the project design and supervisions during the first construction phase of this development in the year 1979 to 1984 period. Hence, the re-engagement of previously involved qualified consultants would be highly recommended for future studies and development, as well as the previous data, knowhow and experience that retained with them would be essential for accomplishing this challenging task.

In addition, consideration should be given to appointing a Panel of Experts from local & overseas professional bodies, who have extensive knowledge and experience in CFRDs, gates and valves, geology, geotechnical engineering, instrumentation and dam safety.

Consideration should be given to employing a minimum number of expatriate engineers and a maximum number of local engineers.

 

Recommendations

Following studies are needed to execute to enhance the project more feasible to meet the challenges in climate change, and the supply of more renewable hydro-energy, especially from the power plants newly built in Mahaweli Basin from the Kelani water.

1. Raising Kotmale Dam (15, 25, 30m). Note all lands are already acquired and there is no social impact;

2. Check the possibility of building dams at locations 11, 12, 14 etc., in Master Plan above Polgolla near Ginigathhena (Koladeniya, Carolina, Trapalga, Rosalla, to increase the retention above Polgolla, as the water about 1,000 MCM / Year is spilling down Polgolla during flood;

3. Enhance the capacity of Kandalama-Huruluwewa Canal to carry about 200 MCM / Year, at a rate of 10m3/second;

4. Built a new tunnel from Bowatenna Reservoir to Dambulu Oya where the capacity is 30m3/second. This would enhance the deficit of water in NWP (150 MCM / Year) and the water need in Anuradhapura;

5. Expand the capacity of power generation in Ukuwela Powerhouse adding one unit; and

6. Revisit the canal availability from Kalawewa to Nachhaduwa, Tissawewa and Basawakulana etc. via Yoda Ela.

7. A supplementary study to check the availability of water from Kelani Basin to Mahaweli Basin would further enhance this proposal.

The writer has B.Sc. Eng. (Hons), M.Eng. (Structural Engineering & Construction), MASCE, MIE Aust, CPEng NER, APEC Engineer, IntPE(Aus).

 

 



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Opinion

We do not want to be press-ganged 

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Reference ,the Indian High Commissioner’s recent comments ( The Island, 9th Jan. ) on strong India-Sri Lanka relationship and the assistance granted on recovering from the financial collapse of Sri Lanka and yet again for cyclone recovery., Sri Lankans should express their  thanks to India for standing up as a friendly neighbour.

On the Defence Cooperation agreement, the Indian High Commissioner’s assertion was that there was nothing beyond that which had been included in the text. But, dear High Commissioner, we Sri Lankans have burnt our fingers when we signed agreements with the European nations who invaded our country; they took our leaders around the Mulberry bush and made our nation pay a very high price by controlling our destiny for hundreds of years. When the Opposition parties in the Parliament requested the Sri Lankan government to reveal the contents of the Defence agreements signed with India as per the prevalent common practice, the government’s strange response was  that India did not want them disclosed.

Even the terms of the one-sided infamous Indo-Sri Lanka agreement, signed in 1987, were disclosed to the public.

Mr. High Commissioner, we are not satisfied with your reply as we are weak, economically, and unable to clearly understand your “India’s Neighbourhood First and  Mahasagar policies” . We need the details of the defence agreements signed with our government, early.

 

RANJITH SOYSA 

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Opinion

When will we learn?

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At every election—general or presidential—we do not truly vote, we simply outvote. We push out the incumbent and bring in another, whether recycled from the past or presented as “fresh.” The last time, we chose a newcomer who had spent years criticising others, conveniently ignoring the centuries of damage they inflicted during successive governments. Only now do we realise that governing is far more difficult than criticising.

There is a saying: “Even with elephants, you cannot bring back the wisdom that has passed.” But are we learning? Among our legislators, there have been individuals accused of murder, fraud, and countless illegal acts. True, the courts did not punish them—but are we so blind as to remain naive in the face of such allegations? These fraudsters and criminals, and any sane citizen living in this decade, cannot deny those realities.

Meanwhile, many of our compatriots abroad, living comfortably with their families, ignore these past crimes with blind devotion and campaign for different parties. For most of us, the wish during an election is not the welfare of the country, but simply to send our personal favourite to the council. The clearest example was the election of a teledrama actress—someone who did not even understand the Constitution—over experienced and honest politicians.

It is time to stop this bogus hero worship. Vote not for personalities, but for the country. Vote for integrity, for competence, and for the future we deserve.

 

Deshapriya Rajapaksha

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Opinion

Chlorophyll –The Life-giver is in peril

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Chlorophyll

Chlorophyll is the green pigment found in plants, algae, and cyanobacteria. It is essential for photosynthesis, the process by which light energy is converted into chemical energy to sustain life on Earth. As it is green it reflects Green of the sunlight spectrum and absorbs its  Red and Blue ranges. The energy in these rays are used to produce carbohydrates utilising water and carbon dioxide and releasing oxygen in the process. Thus, it performs, in this reaction, three functions essential for life on earth; it produces food and oxygen and removes carbon dioxide from the atmosphere to maintain equilibrium in our environment. It is one of the wonders of nature that are in peril today. It is essential for life on earth, at least for the present, as there are no suitable alternatives. While chlorophyll can be produced in a lab, it cannot be produced using simple, everyday chemicals in a straightforward process. The total synthesis of chlorophyll is an extremely complex multi-step organic chemistry process that requires specialized knowledge, advanced laboratory equipment, and numerous complex intermediary compounds and catalysts.

Chlorophyll probably evolved inside bacteria in water and migrated to land with plants that preceded animals who also evolved in water. Plants had to come on land first to oxygenate the atmosphere and make it possible for animals to follow. There was very little oxygen in the ocean or on the surface before chlorophyll carrying bacteria and algae started photosynthesis. Now 70% of our atmospheric oxygen is produced by sea phytoplankton and algae, hence the importance of the sea as a source of oxygen.

Chemically, chlorophyll is a porphyrin compound with a central magnesium (Mg²⁺) ion. Factors that affect its production and function are light intensity, availability of nutrients, especially nitrogen and magnesium,  water supply and temperature. Availability of nutrients and temperature could be adversely affected due to sea pollution and global warming respectively.

Temperature range for optimum chlorophyll function is 25 – 35 C depending on the types of plants. Plants in temperate climates are adopted to function at lower temperatures and those in tropical regions prefer higher temperatures. Chlorophyll in most plants work most efficiently at 30 C. At lower temperatures it could slow down and become dormant. At temperatures above 40 C chlorophyll enzymes  begin to denature and protein complexes can be damaged.  Photosynthesis would decline sharply at these high temperatures.

Global warming therefore could affect chlorophyll function and threaten its very existence. Already there is a qualitative as well as quantitative decline of chlorophyll particularly in the sea. The last decade has been the hottest ten years and 2024 the hottest year since recording had started. The ocean absorbs 90% of the excess heat that reaches the Earth due to the greenhouse effect. Global warming has caused sea surface temperatures to rise significantly, leading to record-breaking temperatures in recent years (like 2023-2024), a faster warming rate (four times faster than 40 years ago), and more frequent, intense marine heatwaves, disrupting marine life and weather patterns. The ocean’s surface is heating up much faster, about four times quicker than in the late 1980s, with the last decade being the warmest on record. 2023 and 2024 saw unprecedented high sea surface temperatures, with some periods exceeding previous records by large margins, potentially becoming the new normal.

Half of the global sea surface has gradually changed in colour indicating chlorophyll decline (Frankie Adkins, 2024, Z Hong, 2025). Sea is blue in colour due to the absorption of Red of the sunlight spectrum  by water and reflecting Blue. When the green chlorophyll of the phytoplankton is decreased the sea becomes bluer. Researchers from MIT and Georgia Tech found these color changes are global, affecting over half the ocean’s surface in the last two decades, and are consistent with climate model predictions. Sea phytoplankton and algae produce more than 70% of the atmospheric oxygen, replenishing what is consumed by animals. Danger to the life of these animals including humans due to decline of sea chlorophyll is obvious. Unless this trend is reversed there would be irreparable damage and irreversible changes in the ecosystems that involve chlorophyll function as a vital component.

The balance 30% of oxygen is supplied mainly by terrestrial plants which are lost due mainly to human action, either by felling and clearing or due to global warming. Since 2000, approximately 100 million hectares of forest area was lost globally by 2018 due to permanent deforestation. More recent estimates from the UN’s Food and Agriculture Organization (FAO) indicate that an estimated 420 million hectares of forest have been lost through deforestation since 1990, with a net loss of approximately 4.7 million hectares per year between 2010 and 2020 (accounting for forest gains by reforestation). From 2001 to 2024, there had been a total of 520 million hectares of tree cover loss globally. This figure includes both temporary loss (e.g., due to fires or logging where forests regrow) and permanent deforestation. Roughly 37% of tree cover loss since 2000 was likely permanent deforestation, resulting in conversion to non-forest land uses such as agriculture, mining, or urban development. Tropical forests account for the vast majority (nearly 94%) of permanent deforestation, largely driven by agricultural expansion.  Limiting warming to 1.5°C significantly reduces risks, but without strong action, widespread plant loss and biodiversity decline are projected, making climate change a dominant threat to nature, notes the World Economic Forum. Tropical trees are Earth’s climate regulators—they cool the planet, store massive amounts of carbon, control rainfall, and stabilize global climate systems. Losing them would make climate change faster, hotter, and harder to reverse.

Another vital function of chlorophyll is carbon fixing. Carbon fixation by plants is crucial because it converts atmospheric carbon dioxide into organic compounds, forming the base of the food web, providing energy/building blocks for life, regulating Earth’s climate by removing greenhouse gases, and driving the global carbon cycle, making life as we know it possible. Plants use carbon fixation (photosynthesis) to create their own food (sugars), providing energy and organic matter that sustains all other life forms.  By absorbing vast amounts of CO2 (a greenhouse gas) from the atmosphere, plants help control its concentration, mitigating global warming. Chlorophyll drives the Carbon Cycle, it’s the primary natural mechanism for moving inorganic carbon into the biosphere, making it available for all living organisms.

In essence, carbon fixation turns the air we breathe out (carbon dioxide) into the food we eat and the air we breathe in (oxygen), sustaining ecosystems and regulating our planet’s climate.

While land plants store much more total carbon in their biomass, marine plants (like phytoplankton) and algae fix nearly the same amount of carbon annually as all terrestrial plants combined, making the ocean a massive and highly efficient carbon sink, especially coastal ecosystems that sequester carbon far faster than forests. Coastal marine plants (mangroves, salt marshes, seagrasses) are extremely efficient carbon sequesters, absorbing carbon at rates up to 50 times faster than terrestrial forests.

If Chlorophyll decline, which is mainly due to human action driven by uncontrolled greed, is not arrested as soon as possible life on Earth would not be possible.

(Some information was obtained from Wikipedia)

by N. A. de S. Amaratunga ✍️

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