Sri Lanka at the Pinnacle of the World in its Water Supplies

Sudath Gunasekara, in The Island, 16 December 2018, were the title is “ Vision and mission on water management in Sri Lanka!”

A recent study on Sri Lanka has identified it as one of the six countries that share one half of the 0.3% drinkable water this planet has. What is even more important and surprising is that ours has been identified as the only country in the world that will have drinking water even if there is going to be a shortage of drinking water in the whole world. This news has made water the biggest asset and the most valuable commodity of Sri Lanka that has put it on the top of the world.

The secret of this unique asset, gifted by nature lies in the following geographical blessings of nature.

Sri Lanka’s relative position on the globe in relation to latitude and longitude, its location in the middle of the Indian Ocean extending up to the Antarctic Ocean, the third largest body of water in the world after the Pacific and the Atlantic Oceans, covering at least 1/5th of the world’s total ocean area open to all sides, being traversed by the Inter Tropical Convergence Zone in relation to the global wind belts, its insularity and its size, the geology and overall topography characterized by a central highland surrounded by a narrow coastal plain in the south-west and south and a broad one in the W, NW, N, East and South-East that has determined the drainage pattern of the Island, the peculiar topography and the nature of alignment of land forms, both vertical and horizontal.

The central mountains have facilitated the interception of the SW and NE monsoons and even influenced the convectional rain in between the monsoons. The forests cover on the central mountains also has contributed heavily and critically on the volume of rainfall and the perennial flow of streams. The forests, with their canopy and the anchoring root system and the underlying geology have influenced the stability of the central hill country and the total volume of water stored by the Central hills both over ground and underground, converting it into the biggest natural reservoir in the country. It also has guaranteed the perennial flow of all major rivers. Thus, all these factors together have made Sri Lanka the first among countries blessed with this nature’s invaluable gift.

In sum, the Central Hill Country functions as the Geographical Heartland of the nation that keeps the entire life system, both fauna and flora, and the civilisation of Sri Lanka alive and vibrant. This is why I call it the Hadabima or heartland. Its physical stability decides the fate of the entire life system in this country as much as the beat of the heart decides the fate of a man. The day the heart stops, a man dies. Similarly, the day the physical stability of the central hill country ceases to exist, the curtain will fall on the entire life system as well as the civilization in this country. This critical and unique situation calls for the protection of the Central Hill Country as the ‘Heart’ of the nation, and the mother watershed of the country, acting as a natural reservoir providing perennial water. All these factors have contributed heavily to elevating this country to the first place among the countries with drinkable water. Against this backdrop, perhaps, we could rise as a water exporting country in the future to this thirsty world. Sri Lankan water could be even a big foreign exchange earner in times to come, provided we protect this national wealth.


The Geographical Heartland of sri lanka

Next let us look briefly at what climatological factors have contributed to this nature’s asset.

The first is the heavy rainfall. Mean annual rainfall in Sri Lanka is around 2000 mm (Arulanandan 1985) distributed over the surface area of 65, 610 square kilometers. This gives an average volume of 131, 230 million cubic meters (m3) of fresh water. Rainfall is received from the South-West Monsoon (May – September), North-East Monsoon (November to March), and between the monsoons through tropical convectional developments. Thus generally the island is blessed with rain throughout the year.

Average annual river flow 31% of the Rainfall 40,680 million m3 (Bocks 1959) (going to the Sea) The balance 69% (90, 550 million m3) is used and transpired by crops and natural vegetation or evaporate from the soil directly to the air 65 % of the wet zone catchment rainfall is discharged in to rivers. Out of this 77% is discharged by Kalu Ganga

Although the overall whether pattern may not have changed over time, things like decreased annual rain fall, increased river flow and resulting loss of large volume of water into the sea, depletion of the ground water table, increase of surface run off and erosion and land degradation have enormously increased due to large scale deforestation (over 600 000 acres on the central watersheds) after the introduction of plantation agriculture to the central hill country in the mid-19th century. Regarding the reduction of the volume of water in the Uma Oya, Samuel Baker has observed that the flow of Uma Oya was reduced by 50% after deforestation for plantations. This again highlights the importance of protecting the forest cover on the Central Water Sheds of this nation. This perception is further proved when Arnold Toynbee said, “Ancient Sri Lanka once achieved the tour de force of compelling monsoon smitten highlands to give water, life and wealth to the plains below.” Therefore, it is now well established that plantation agriculture introduced by the British has severely affected the pre-colonial water potentialities of this island. In spite of this devastation of over 600,000 acres of virgin forest by the British colonials, I am surprised to note that world authorities have found that this country is still on the top of the six countries that have the highest potentials of drinking water. Imagine what would have been the position if the original forest cover was there intact.

What the Sri Lanka Government should do: First to maintain the status quo, and then to restore the pre-1815 situation. I strongly believe that no government in the post-Independence period has governed this country properly. None of them has realised the country’s potentials or how it could be developed. Nevertheless, assuming that at least in the near future the people of this country will get a people’s government elected, I will make few proposals here for it to implement.

Firstly, in order to maintain the status quo in relation to the water situation mentioned above, and secondly, to protect the Central Hill Country and restore the physical stability of the hill country to its pre-1815 conditions, and in order to achieve both these objectives the first thing we should do is to restore and protect the central hill country, the country’s “Geographical HEARTLAND”.

That will be the cornerstone of this whole programme. In order to fulfil this task we should treat the hill country in three parts: namely a) 300-900m (1000-3000ft), b) 900-1500m (3000-5000ft) and 3) above 1500 m (5000ft)

1 Step One

Declare all lands over 1500m (5000 feet) above sea level as a strict conservation area (Thahanchikele as it had been before 1815 and) and re-afforest them with endemic vegetation in areas where natural re-generation does not take place. Planting exotic trees like Pines, Gum and Cinchona or any others should be totally banned. No development work or settlements should be allowed within this region

2 Step Two

Limit tea plantations to 900-1500m lands with strict land use policies and cultivation practices like strict soil conservation policies, banning cultivation on land over 60% slope, defined riparian belts, critical water sheds and limiting settlements to meet bare necessities such as factories, administrative buildings and settler clusters in suitable places. Establishment of villages in this region should be immediately stopped.

3 Step three

Land over 300-900m (>1000-3000ft) should be used for smallholder farm settlements of mixed crops like tea, coffee, pepper and cloves, Kandyan Forest Gardens, Dairy farming and settlements preferably managed on a cooperative basis. The Sri Lanka HADABIMA Project could be entrusted with this responsibility as it has thae required experience and knowledge to handle this aspect of Agricultural development. The same model could be replicated in areas below 300 m (1000ft) where possible (There will very little problems here as this region already has this model under traditional village settlements system).

If these land use policies are properly implemented in these four regions, the first and most important watershed management followed by solving landlessness and rural economic development of the upcountry of Sri Lanka will be completed. This will also complete the rehabilitation problem of the neglected Kandyan Peasants that has been hanging on from 1951.

Managing river flows and storing the maximum volume of water

This is the next important step in this national water management Programme. We noted above that 65% of the total annual rain water is just allowed to flow to the sea as river flow. If we could save at least 50 % of this volume, it would significantly enhance the water availability and agricultural potentials of the country.

There are two ways of doing it. The first is by storing it in reservoirs as is being done at present by trans-basin diversions on land like Minipe Ela and Jayaganga that takes their waters to Polonnaruwa and Anuradhapura respectively. The second is by diverting by tunnels where it is appropriate, as it is done at Polgolla, which takes the waters of Mahaweli to NCP and at Nalanda to Kala Oya, through the Lenadora Tunnel. These are the only two project undertaken in this field in modern times though there is another unknown but marvellous trans-basin diversion called the Pattipola Bhoo Ela, a medieval diversion where the waters of Damabgastalawa (a head stream of Kotmale Oya is diverted through a tunnel measuring 10 ft in diameter, 40 feet below surface level to the Uma Oya. The ongoing Uma Oya – Kirindi Oya tunnel Diversion (the controversial) also could be grouped under the same category. I would like to mention two other new proposals that have not been attempted either in the ancient times or the modern.

a) Diverting Kalu Ganga waters to Walave going up to even Kirindi Oya

b) Diverting Kelani waters to the NW

Diverting Kalu Ganga to South and South East will be even more important than Kelani waters to NW for Four reasons. Firstly, Kalu Ganga is the river that discharges the biggest volume 77% of (7862million M3) out of the total of 65% percent of Wet Zone catchment rainfall to the sea. Secondly, it is the least used river for irrigation purposes. Thirdly, it is also the river that brings the highest flood devastations and finally, its diversion could enhance the Walawe potentials while bringing a new lease of life to the drought stricken South and South-Eastern lowlands. This will also be a novel idea hitherto not tried by policy makers or planners.

I remember my good friend and eminent irrigation engineer, D.L.O. Mendis, once mentioned to me about a proposal to this effect he mooted. But it has never seen the light of the day. A trans-basin canal passing through the Denavaka valley, and thereafter that traverses along the foot hills of the Southern Great wall extending even up to Kirindi Oya, might be able to transform the geographical landscape of the whole region through new settlements, new agricultural activities and agro-base industries. If constructed, this canal also will be the longest man made irrigation canal in Sri Lanka.

The next is diverting Kelani waters to the NW. If the topography does not permit taking water under gravity by a canal, then alternative techniques should be devised to take the water to the required area. This will put an end to the water problem in drought stricken North Western Province. Kelani River also discharges 5,474 million cubic meters to the sea annually.

Furthermore, both these projects if undertaken will also reduce the present flood hazards and enable us to make use of the enormous volume of water presently going down to the sea annually.

Constructing Barrages

Constructing barrages in all suitable places along the rivers technically feasible to collect water and control floods. I do not know anyone has even given serious thought to this idea. It was only last week one Sunil Gamage, a Vet scientist and my friend who came out with this bright idea, as we were discussing the merits of the Polgolla diversion as against the controversial Uma Oya diversion. I think this is a wonderful idea in many aspects. A large number of benefits such as storing river flow to be used at lean times, enhancing the ground water table in the neighbourhood, downstream flood control, reducing serious siltation in downstream reservoirs enabling them to store more water (as happened in Kuluweva in the Dry Zone in ancient times), increasing the irrigation and hydro-electricity generation capacities of major reservoirs like Victoria, Randenigala and Rantembe, and providing new locations for river diversion.

Victoria Dam

Regular maintenance of Dry Zone tanks and irrigation works

It is a well-known fact that poor maintenance of these works has led to enormous wastage of valuable rain water the country receives annually, flowing down to the sea. We also had a very rich tradition of annually de-silting and repairing of tank bunds and repairing all irrigation canals as a community responsibility. The catchments and wevtavulu were protected as strict reservations and they never disturbed, unlike today. These practices of a farmer community have become things of the past. As a result, all major tanks are filled with silt, and therefore the storage capacities of almost all tanks have got reduced. Following a few showers tank sluices are opened for the water to escape fearing dam breach. The net result is the loss of enormous volumes of precious rain water going down to the sea unused. But meanwhile, I have seen some people talking about harvesting rain water in artificially constructed tanks. Isn’t it a pity and a tragedy too that these people have not even understood the difference between a natural reservoir and massive cement plastered concrete tank. Even if our modern engineers go for concrete tanks under the concept of modernization in place of natural reservoirs one should not get surprised. As for me, I am also against concrete canals replacing natural canals, though they have long distance carrying capacity, as they miserably fail to maintain natural advantages.


Generally, the importance of water in our civilization was properly understood by our ancient Kings. Among them, Dhatusena, Kasyapa, Vasabha, Mahasena and Parakramabahu the Great, rank pre-eminent. It was Parakramabahu the Great (1153-86) who said that, “Not a single drop of water that falls from the heaven should be allowed to escape to the sea without being utilized for the benefit of man”. Obviously they knew the value of water in our culture. Thus, although we owe a rich water conservation legacy (perhaps the best in the ancient world), of water management as expounded by them, unfortunately, later generations have paid little or no attention to this philosophy on water management of our forefathers. The present day rulers are clueless of this great tradition. They are only concerned with personal gain and power.

The ancient Kings never constructed reservoirs in the hill country. Except in few places along the Mahaweli Ganga that went up to Kotmale; they never opened up settlements in the hill country either. They had protected and prohibited the whole hill country as the nation’s mother watershed untouched (thahanchikele). Therefore, I strongly recommend the need to revisit the ancient wisdom and to commence a vigorous programme of restoring and protecting the central hill country immediately, as the cornerstone of this programme and then de-silt and maintain the tanks and irrigation canals annually. This has to be supported by a very strict water management policy particularly in the irrigation sector, as suggested by eminent scholars like Prof G.H. Peiris in his study on Minipe as there is an enormous wastage of irrigation water by our farmers, compared with countries like Pakistan. Thereby, we can increase the acreage cultivated. It would also be interesting to note here that in the ancient times they have cultivated three kannas a year.

This is to be followed up by the proposals as mentioned under “Managing river flows and storing the maximum volume of water” above.

I hope for a new vision and a novel mission in water management in Sri Lanka for policy makers and Planners!

1 Comment

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One response to “Sri Lanka at the Pinnacle of the World in its Water Supplies

  1. Sanath de Silva

    Wonderful plan, Michael!
    People are like Li’l Kids with a Candy Jar – need Elders to guide them creatively!

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