ANCIENT IRRIGATION SCHEMES BASED ON THE MAHAWELI GANGA.

ANCIENT IRRIGATION SCHEMES BASED ON THE MAHAWELI GANGA.

            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)