Historical Background - Mahaweli Authority and Others

From the Website of the Mahaweli Authority of Sri Lanka

Images inserted later

Courtesy : Engr. Sudharma Elakanda

 Historical Background 

The original idea of diverting the Mahaweli Ganga was very much in the minds of our ancients. They diverted it at Minipe, Kalinga, and Kandekadu along the main river. They also diverted the main branch of the Mahaweli, namely, the Ambanganga , at Elahera and Angamadilla. They were in a position to do so at that time using the river water to cultivate vast acreages of paddy since the flow was copious, with the upper catchment being well forested. The lesson we learn is that we should emulate the wisdom of the ancients by encouraging the reforestation of the upper catchment rather than building new dams like Upper Kotmale. They had even diverted the waters across basins from the Amban ganga to the Kala Oya Basin. This trans basin diversion was achieved by diverting the spill waters from a dam at Demata Oya in the catchment of Amban Ganaga to the catchment of the Kala Oya in a unique and classical way.

Proposed Development Area showing Ancient Dams - UNDP/FAO Report 1969

Our ancients further built reservoirs in the B.C. period using a sluice. A unique device developed by them, which could control water issues up to a water head of 30 feet, or 10 metres. When they had to control water heads over 30 feet, they solved this complex problem by simply replicating the sluices at different levels, so that they always operated them at heads of less than 30 feet starting from the topmost sluice. These instructions were clearly inscribed in stone for all to strictly follow; any deviation from these instructions would have spelt disaster, with the sluice failing.

The Maduru Oya Ancient Sluice discovered in 1978 during Jungle Clearing Operations
Veteran Engineer M. S. M. de Silva
was living at the Site in a Caravan

Our hydraulic civilization had a temporary setback in the 11th century with the incursion of chola invaders when they laid waste the irrigation works in the Rajarata, and the capital Anuradhapura had to be shifted to Polonnaruwa. The ancient hydraulic civilization reached its climax under Parakrama Bahu the Great in the 12th century. His motto was:

"It is not meet that men like us

Should live and enjoy what has come to our hands

And not care for the people.

In a country like this not even the least quantity

Of rainwater should be allowed to flow to

The ocean without profiting man.

Let there not be left anywhere in my kingdom

A piece of land though it be of the smallest dimension,

That does not yield some benefit to man"

The renowned hydraulic civilization that was known the world over as supporting the granary of the east for several millennia, fell in the 13th century. Though historians conjecture that the fall of our hydraulic civilization was due to the incursions of Kalinga Maga, followed by the Javanese Chandra Bhanu, scientific evidence from aerospace surveys have confirmed that the real reason for the fall of our hydraulic civilization was a cataclysm in the 13th century. 

This was discovered in 1965 in the course of investigations for the Mahaweli project in the planning stage.

The unique sluices that were developed by our ancients were found in all major reservoirs.  Several ancient sluices were discovered and recorded at first hand for posterity by renowned pioneers and scholars in the course of field investigations. Among them were Dr John Davy, Sir Emmerson Tennent (1845), Henry Parker (1890) and R. L. Brohier(1933).

During the British period after the pioneering work of Henry Parker, who investigated our ancient irrigation works based on isolated contour surveys and not connected to a level network in respect of levels, the then government commenced the production of a one mile to the inch Topographical Survey of the entire country. This survey was conducted by pioneer surveyors in the Survey Department who did so under trying conditions and it revealed the numerous ruins of ancient irrigation works both large and small and their interconnections, as well as the numerous connected monuments of our ancient hydraulic civilization. 

The British commissioned in 1900 a renowned Irrigation Engineer, Mr. W.T. Strange, to report on the ancient irrigation works discovered by Mr. Henry Parker and recorded by the Survey Department. It was he who first recommended that the Mahaweli Ganga be diverted to the Dry Zone as our ancients had done before. 

In the meantime, the Survey Department started to establish a level network. That was essential to undertake any necessary restoration and diversion structures. With the availability of the one inch to the mile topographical sheet and the level network, it was most fortunate that Hon D. S. Senanayake commissioned R.L. Brohier to report on the Ancient Irrigation Works of Ceylon. This Brohier did in 1932 in a very short time of two years making use of all the information available to him. His "Ancient Irrigation Works of Ceylon" is a classic and will continue to be a reference work on the subject for all time. It needs updating only when new facts emerge, such as when new investigations are undertaken like in the Mahaweli Basin, which is very rare.

Our early leaders D.S. Senanayake, Bulankulame Dissawa, Dudley Senanayake, C.P. de Silva and many others were inspired by our ancient heritage, having read the works of scholars, especially those of Henry Parker and R.L. Brohier, and made various suggestions to direct the waters of the perennial Mahaweli to the parched dry zone for the benefit of our people. Special mention would have to be made of the Hon C.P. de Silva, the then Minister of Lands, Irrigation and Power who pushed the project at every level, and at every stage, till the completion of the Feasibility Studies and the Inauguration of the Project in 1970.

Preliminary studies in this connection were first made by the irrigation Department. The Resources of the Mahaweli Basin were studied by the Canada Ceylon Colombo Plan Project using modern aerospace techniques and was also concurrently done by the USOM. Both these Studies were done in the late fifties in close cooperation with the Survey Department, the Irrigation Department, Agriculture Department and other government departments, and published. These studies indicated that there would be a surplus of water according to the envisaged plan and therefore the government wanted to modify the plan to fully utilize the Mahaweli Waters by diverting these excess waters to adjacent basins. As a consequence the FAO/UNDP were requested to prepare a Master Plan to include trans basin development. This was also done in collaboration with all the departments which collaborated in the earlier studies. This Master Plan was completed in 1968.

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July 06, 2017

ANCIENT IRRIGATION SCHEMES BASED ON THE MAHAWELI GANGA.

By  Yasantha de Silva

           The 'Mahaweli" Development Scheme (MDS) to provide water for dry zone, Agriculture, which commenced in 1969, is preceded by an Ancient Irrigation  scheme, which utilized the Mahaweli Ganga. The ancient chronicles, the Mahavansa, Culavansa, Pujawaliya etc, the notes by Sir Emerson Tennent and Mr. C.U.Nicholas and Survey work by Mr. Henry Parker and Dr.R.L. Brohier indicate that the Mahaweli Ganga and its tributary the Amban Ganga were the perennial sources of water for the intricate  irrigation network. 
            4 anicuts across the Amban Ganga and 2 across the Mahaweli Ganga fed seven channels while provided water and augmented a large number of major tanks and thousands of small tanks spread in the basins of the Kalaoya, Moderagam Aru, Malvatu Oya, Yan Oya, Kantale Oya, Amban Ganga and the Mahaweli Ganga in the dry zone. 

            Unfortunately the inability of the late Mr.D.S.Senanayake to set up a Research Institute or a University to study the ancient Irrigation works, when he became the Minister of Lands and Agriculture of the state council in 1931 or the prime minister from 1948 to 1952, pushed the Ancient Irrigation system to oblivion and presented a chance for foreigners to dictate the MDS which destroyed the grandeur of the ancient Irrigation Heritage of Sri Lanka.

Details of the Ancient Mahaweli Scheme.

1.      Demada Ancut

      It was constructed across the Demada Oya, which is a tributary of the Amban ganga Water from Damada oya was conducted via a channel to Welimiti oya which led to the Dembulu oya, which flowed into the Kala Wewa. This Demada anicut and the channel was constructed by King Dhatusena (460-478AD) Parts of the channel had been hoted by Dr.R.L.Brohier. The Mahaweli Project Report does not mention of the Demada Anicut and its channel.

2.      The Hattota Anicut

      This was constructed by King Aggabodhi II (601 to 611 AD) across the upper reaches of the Kaluganga, which is a tributary of the Amban ganga. A 20 mile channel from the Anicut led water to the Elahera Anicut, to increase the argumentation to the Minneriya and Giritale tanks, The Kaluganga reservoir would cover the ruins  of the Anicut and the channel. 

 

3.      The Elahera Anicut

      The Elahera was construted by King Vasaba (67-111AD) on the Amban ganga to conduct water to the Minneriya tank by a 20 mile channel. It was improved by King Mahasen (274-302AD)

4.      The Angamedilla Anicut

      It was built across the Amban Ganga by King Upatissa (368 - 409AD), and water was led to the Topawewa tank by a 12 mile long channel known as 'Akasa Ganga'. It was improved by king Parakkramabahu I (1153-1186AD) to conduct more water to the Parakkrama Samudra. Sir Emerson Tennent's comment in 'Ceylon' (1859) indicate that the Akasa Ganga was in good condition even during 1845-1850AD.

 

5.      The Minipe Anicut

      It was built across the Mahaweli Ganga by king Aggabodhi I (568-601AD), and water distributed directly to the fields, by the 40 mile long 'Minipe Channel'. The channel was extended to the Angamedilla anicut by king Sena II (851-885AD), in order to increase the supply on the Akasa Ganga to Topawewa, by addition of 'Mahaweli Water' also to Akasa Ganga.

 

6.      The Kalinga Nuwara Dam

      This is a stupendous dam constructed by king Mahasen (274-302AD) on the Mahaweli Ganga, below Manampitiya. The left bank channel, the Kalinga yoda ela, was 36 miles long, and the right bank channel, the Gomati ela, was 30 miles long. The Gomathi ela had a 8 mile long channel to the Maduru oya basin. The Kalinga Dam and both its channels are now in ruins.

            The water from all the above anicuts and dams was taken by a fine and intricate system of transbasin channels, some of which are mentioned below, to all the river basin of the Rajarata to increase paddy cultivation. Outstanding kings continued to improve the irrigation works using their engineers, technicians and labour force with mammoties & baskets and elephants until the end of the reign of king Parakkaramabahu The Great in 1186AD.

Tanks, Anicuts, Channels	Founder	River Rasin	Original Augmentation Source and Details
Tissawewa and Basawakkulama Tanks	King Pandukabaya (438 - 367)BC	Malwatu Oya	Demada Anicut King Dhatusena (460-478AD) Via 'Jaya Ganga' from Kalawewa
Katiyawa Tank	King Dutugemunu  (161-137BC)	Malwatu Oya	Demada Anicut King Dhatusena Via the 'Jaya Ganga'
Balalu wewa Tank	King Kutakannatissa (44-22BC)	Kalaoya	Demada Anicut King Dhatusena
Kalawewa tank incorporating Balaluwewa tank	King Dhatusena (460-478AD)	Kalaoya	Demada Anicut King Dhatusena Dambulu oya to Kalawewa.
Mahavilachchiya and Kudavilachchiya tanks	King Vasaba (67-111AD)	Modaragam Aru	Demada Anicut King Dhatusena in 460-478BC the extension of the Jaya Ganga
24 mile long transbasin channel from Basawakkulama to Mahavilachchiya	King Dhatusena	Malwatu Oya to Maderagama aru	Demada Anicut King Dhatusena Transbasin channel connected to Jayaganga
Tanks, Anicuts, Channels	Founder	River/ Rasin	Original Augmentation Source  and Details
Kaudulla Tank	King Mahasen (274-302AD)	Mahaweli Ganga	Elahera Anicut King Mahasen, extension of Elahera channel
Usgala Siyabalangamuwa tank	King Mahasen	Kalaoya	Demada Anicut King Mahasen, Balaluwewa Ela from Balaluwawa tank
Mahakanadarawa tank	King Mahasen	Malvatu oya, Kalaoya	Demada Anicut King Sena II (851-885 AD) a transbasin Channel from Dambulu oya to Mahakanadarawa tank
55 mile long 'Kalawewa Tissawewa Yoda Ela', (Jaya Ganga) from Kalawewa to Tissawewa	King Dhatusena	Kala oya to Malvatu oya	Demada Anicut King Dhatusena the channel had a drop of 6" per mile for the first 22 miles of its length
Giant's tank at Manner, 12 mile long Alawakku channel from Alawakku Tekkam (anicut) across Malvatu oya	King Dhatusena	Malvatu oya	Demada Anicut All 3 constructions King Dhatusena
Nachchaduwa tank, 7 mile channel from Jaya ganga to feed it	King Moggallana II (537- 556AD)	Malvatu Oya	Demada Anicut King Moggalana II, channel is now in rains
Tanks, Anicuts, Channels	Founder	River/ Rasin	Original Augmentation Source and Details
5 mile long channel to Nuwarawewa from Nachchaduwa tank	King Moggallana II	Malvathu Oya	Demada Anicut King Moggallana II (Channel now in ruins)
10 mile long channel from Nuwarawewa to Maha galkadawela tank	King Moggallana II	Malvathu Oya	Demada Anicut King Moggallana II
Anicut across Dambulu Oya with 38 mile channel to Mahakanadarawa tank	King Sena II (851-885AD)	Kala oya Malvatu oya	Demada Anicut Both anicut and channel by King Sena II

The achievements of the ancient irrigation systems, especially of the North Central Province, have amazed many administrators, irrigation engineers, surveyors and scholars from the commencement of British Colonial rule in 1815AD.

            Sir Emerson Tennent who was the resident Colonial Secretary of the British Government in Ceylon from 1845 - 1850, in his book 'Ceylon' (1859), makes the following comments of the irrigation works of ancient Ceylon as follows:

            "The stupendous ruins of the reservoirs are the proudest monuments which remain of the former greatness  of the country"  . . . . " no similar construction formed by any race, whether ancient or modern exceeded in colossal magnitude the stupendous tanks in Ceylon". His elaborate, appreciative comments could be summarised as follows:" The grandeur of Kalawewa and Padivil colon (Reference to the Padaviya tank) and the channel which connected " the Ambanganga river to the sea of Parakkrama" (reference to the Akasa ganga and Parakkrama Samuddra) far surpassed all other artificial lakes and all subterranean or surface channel systems found anywhere in the world.

            Mr. Henry Parker, who held the post equivalent to the present Director of Irrigation in the British Colonial Government from 1873 to 1904 and recorded his observation on the Irrigation works of Ceylon in' Ancient Ceylon' (1909) ' states"It must have been no easy tank to control the outflow of the water at reservoirs which had a depth of thirty or forty feet, as was the case of several large works. Yet the similarity of the design of the Bisokotuwas (Valve pits) at all periods, proves that the engineers of the 3rd century BC, if not those of an earlier period, had mastered the problem so successfully, that all others were satisfied to copy their design. It was this invention alone which permitted the Sinhalese to proceed boldly with the construction of reservoirs that still rank among the finest and greatest works of its kind in the world".

            Mr.Parker also make special mention of the priceless, Ancient Irrigation Heritage .... "It we rashly think, after a mere glance at the site (in comparison on the other hand with the actual practical experience of the Sinhalese for nearly 1000 years), that we can change all that and effect untold improvements, we may find, when too late, that they were right and we are wrong. Experience constantly impressed on me that if their was one subject which these wonderful old engineers understood better than another, it certainly  was the irrigation of paddy fields and the designing of, at least, in outline of the great structures which were needed to for that purpose".

Yasantha De Silva BSc (Agriculture)