Waterworld: Modern irrigation Projects of Sri Lanka

Gal Oya Scheme (1952, Don Stephan Senanayake, the first prime minister of independent Ceylon, the father of Modern Sri Lanka)
Gal Oya Scheme is one of the largest 4 modern irrigation projects of Sri Lanka. This scheme involved the restoration of a number of ancient medium scale reservoirs & construction of the Senanayake Samudra (7680 ha), the largest reservoir in the history of Sri Lanka. Senanayake Samudra is one of the main project of the Scheme. As the Ceylonese (majority Sinhalese + minorities, i.e. Tamils, Moors, Burghers & other citizens of Ceylon, as then called) minister of agriculture in the pre-war cabinet under the British rule, D. S. Senanayake had devoted himself to restoring the derelict irrigation schemes of ancient Anuradhapura & Polonnaruwa. Then again, as the first prime minister of independent Ceylon, the father of modern Sri Lanka, Right Honourable D. S. Senanayke looked up to the genius of King Parakramabahu the great (1164-1196 AD) who constructed or restored 165 dams, 3910 canals, 163 major reservoirs and 2376 minor tanks.

Gal Oya Project reveals: Modern irrigation engineers Vs. Ancients irrigation masterminds.
The Modern Gal Oya Project (1952) too testified to the brilliance of the ancient masterminds of irrigation engineering in Lanka: the discovery of remnants dated back to 2000 years of a dam site and two sluices almost exactly at the locations determined for the new reservoir by the engineers at the Gal Oya project. In order to preserve the excavated ruins of the dams & sluice gates, the priceless archeological findings, the government decided to move the new dam site to another location.

Walawe Ganga Scheme (1965)
This scheme involved the construction of three major reservoirs, the Uda Walawe rainwater reservoir (3415 ha), the Chandrika Wewa (448 ha) and the Ridiyagama Reservoir (888 ha). It also involved restoration and construction of minor irrigation reservoirs, anicuts and channels.

Modern reservoirs

Year 1952: Senanayake Samudra reservoir covering an area of 7680 ha
Year 1984: Ulhiyiya - Ratkinda reservoir covering an area of 2270 ha
Year 1984: Maduru - Oya reservoir covering an area of 6280 ha
Year 1985: Victoria reservoir covering an area of 2270 ha
Year 1985: Kotmale reservoir covering an area of 970 ha
Year 1986: Randenigla reservoir covering an area of 2750 ha
Year 1986: Lunugamwehera reservoir covering an area of 3023 ha

Mahaweli Ganga (Mahaweli River) Scheme, the largest irrigation & development scheme ever in Sri Lanka (1970)

River Mahaweli
"The Mahaweli Ganga, is the river of Ceylon; its discharge is not only much larger than that of any other river in the island, but what is probably of the greatest advantage is, it is of considerable amount throughout the year, as the catchment is visited by both the South-West & North-East Monsoons." William Strange (1909)

"The Mahweli Ganga is not just one river... but a composite... drainage system. It has grown as a parasite, at the expense of other rivers, capturing & sapping them & diverting to itself the rainfall discharge of a larger area". K. Kularatnam in a University Review 1962.

Sri Lanka's longest river, the River Mahaweli, originates at Adam's Peak, meander past Kandy, the gateway to the Central highlands & through the eastern province to complete its 335km sourjourn at Trincomalee, one of the finest natural harbours in the world. The river was first harnessed for irrigation in the third century B.C., though it wasn't into 1960s its full potential began to be realized with the commencement of the monumental Mahaweli Development Project, the largest irrigation & development scheme ever attempted in Sri Lanka.

Length: 355 km (longest River in Sri Lanka)
Climate: equatorial and tropical
Precipitation: wet zone: +250 centimetres; dry zone 120 to 190 centimetre

Multi-purpose development scheme
The purposes were to generate hydro-electric power, to provide irrigation for dry-zone cultivations, & settlements for the landless & unemployed through the development of physical & social infrastructure for human habitations.

Inclusion of other river basins
The Mahaweli Ganga multi-purpose development scheme includes two other river basins, i.e. the Maduru Oya and Kala Oya basins. The grand scheme not only incorporates some existing reservoirs into the system but also involves the construction of a number of major reservoirs for the generation of hydro-electricity and for irrigation.

Accelerated Mahaweli Programme (AMP) launched by President J. R. Jayawardena & Minister Gamini Dissanayake

The harnessing of waters of the River Mahaweli was the prime purpose of the Accelerated Mahaweli Programme begun in 1977. By 1995 the settlement program was substantially completed, with over 80,000 families settled in various sections of the entire project. Special attention was focused on wildlife & forest conservation with four national parks & two nature reserves established, covering 45% of the land area included in the AMP. The project involves production of 508 MW of power and development of 364,000 Ha. of land for irrigated agriculture and human settlement.

A series of dams
The project aimed to construct a series of dams across the river, most notably the enormous Victoria Dam just east of Kandy, in order to irrigate huge sections of arid & thinly populated land in the east & open them up for farming for the development of the island, the betterment of its populace. The vision can be seen in reality at the Victoria Dam where the Victoria - Randenigla sanctuary covers 4600 hectares.

Randenigla Reservoir Dam
The Randenigala Project, the fourth major multi-purpose project and the largest reservoir under the Accelerated Mahaweli Development Programme. Randenigala project is located about 26 km. below the Victoria Head works and 6 km. upstream of Minipe anicut from where the main Right Bank and Left Bank canals will divert the Mahaweli waters for irrigation. It is also the reservoir with the largest storage capacity having gross storage of 860 million cubic metres (697,000 acre ft.) at full supply level.

The dam construction is 94 m high, 485 m long Rock-fill dam across Mahaweli, created a reservoir of 860 million cu.m. The dam straddles the last gorge before the 365km long River Mahaweli River plunges to the plains. Its crest is 485-m long & 94m high.

The Victoria Dam, Sri Lanka
The Victoria dam is located in a deeply incised gorge in the Dumbare Valley, immediately downstream of the confluence of the River Mahaweli & the Hulu Ganga river in Teldeniya. It is a double curvature arch dam,122m (400ft) high, & 507m (1663ft) long measured along the crest. Its design is said to be the most suitable for the geological conditions & terrain obtaining at Victoria. It has created a storage reservoir of 730 million cubic meters & a power capacity of 210 MW.

A unique feature of the Victoria dam is automatically opening spillway crest gates to water when the reservoir level rises beyond full supply level. Her Majesty Queen Elizabeth the second & His Royal Highness Prince Philip visited the Victoria project site in October 1981. On April 7, 1984 the Victoria reservoir was impounded & it started filling up fast with unusually high rainfall in the central highlands.

12th April 1985, British Prime Minister Margaret Thatcher at the commissioning of Victoria Dam, Sri Lanka

Quote
"For centuries Mahaweli Ganga has flowed unchecked through these hills. With the commissioning today of the Victoria dam, its energy is harnessed to a noble cause-the development of the full potential of your land, your natural resources & your people. This great engineering feat is a product of the modern age but it rests on a tradition stretching back some 2000 years. In the days of the ancient kings' mighty irrigation works were the heart of a flourishing civilization... Visitors from many countries will marvel at the Victoria dam, at the functional elegance of the designs, & the quality of the engineering skills which went into this great achievement...
...But development is not about concrete however carefully poured, not about power stations however efficiently run. It is about people, their land, their homes, their families, their future; it is people who have brought this project into being, people who have sacrifices for it, people who will operate it & people who will benefit... So, Mr. President, it gives me great pleasure to join you in declaring the Victoria dam & power station well & truly commissioned. May it fulfill its purpose of a better life & happy future for your people-the people of Sri Lanka."
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12th April 1985, President J. R. Jayawardene of Sri Lanka at the commissioning of Victoria Dam, Sri Lanka

Quote
"Never in the history of the human race has water been collected at one spot, in one reservoir, as a gift of one nation for the benefit of another nation, in so short a time as has been accomplished by the making of this Victoria dam. On behalf of the government & the people of Sri Lanka, since you have provided the water to those living today & those to live tomorrow, & since water is life, I give our sincere thanks to you Madam, Mrs. Margaret Thatcher, your predecessors in office & the people of United Kingdom."
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