Liste der Herrscher von Sri Lanka - Parakramma: King Parakrama (1153 – 86) had said: “Not a single drop of water received from rain should be allowed to escape into the sea without being utilised for human benefit”
Geschichte Bearbeiten
The first documented construction of a reservoir is from the early fourth century bce built by Prince Anuradha in Anuradhapura still in existence and known as the Basawakkulam tank of some 120 ha.
The formal systems Anuradhapura The second tank to be built at Anuradhapura was the 160 ha Tissa Wewa created by King Tissa in the 3rd century bce, which fed the Royal Pleasure Gardens. A system of canals, conduits and channels link the reservoir to the bathing ponds in the gardens where the king and queen would bathe. The reservoir is fed from the river 37 miles away by a channel that has a gradient of 1 inch/mile. The channels feeding the ponds are sinuous with settlement chambers which allow sediment to be removed before entering the ponds. Other ponds around this ancient city include the Elephant Pond and the Twin Ponds. These were both for the monks to bathe and date from 7-800 AD. They are both fed from the tanks and decoration includes the 5 headed cobra found throughout Sri Lanka which is reputed to ensure a constant supply of water. After the bathing ponds, the water overflows to fields for irrigation which include onions, aubergines, corn as well as rice. Before some of these ponds were restored during the 20th century they appeared even more remarkable than they do today: ‘there is something very weird about these remnants of ancient luxury hidden in the lonely forest’ (3) Around Anuradhapura I also saw a number of ancient urinals or bidets. They have decorated platforms set above 3 clay pots buried one on top of the next. The pots are about 2 ft in diameter and are filled with sand, lime and charcoal to purify the water before it soaks into the ground. Traditional Sigirya After the fall of King Dhatusena of Anuradhapura in 477AD his son Kasyapa built a rock fortress at Sigiyra. The approach to the granite rock (the Lion Rock) is surrounded by inner and outer moats and formal water gardens; water is fed by underground and surface drainage systems from elevated tanks during the rainy season, to form water spouts and fountains. On the top of the 200m high rock is a 25m square pond hewn out of the rock for water storage. The water gardens themselves were used for bathing by the various members of the King’s court. The Fountain Garden has two long ponds with stepped sides fed by shallow serpentine streams paved with marble. These serpentines are punctuated by fountains consisting of circular limestone plates with perforations. They arte fed by underground water conduits and operate by gravity and pressure. Water for the town was stored in the Sigiriya Wewa. Polonnaruwa Polonnaruwa became the capital of Sri Lanka after the destruction of Anuradhapura in 11th century but only lasted as a capital until the 12th century. It was fortified by King Parakrama and linked the existing reservoirs to create his ‘sea’ or samudra. Apart from seeing the various temples and other historic buildings, the principal purpose of this visit was to see this remarkable reservoir which covers 2500ha. Its bund is 12m high and is 13.67km long; it irrigates an area of 28sqmiles of paddy. The embankment required 4.6 million cu.m of fill which remained a world record until 1912 when the Gatun Dam was built for the Panama Canal. (7) The reservoir was restored by the British in the 19th century when a new sluice was provided. When all else fails… The annual festival of the Esala month (July/August) held in Kandy at the end of the drought period is marked by a procession, the Perahera. This is a rain-making festival held in honour of the Buddha’s Sacred Tooth Relic which Buddhists believe has the power to cause rain. (It is held in Kandy since this was the last royal capital before the British occupation – after which, in 1815, the capital was moved to Colombo). The Tooth Relic is kept in the Temple next to the banks of the Tank, the Nuvara Veva, built by the last king of Kandy, Sri Wickrama Rajasinghe. It was constructed in 1810-12 by the damming of a stream which ran through the marshes that skirted the town. The Perahera is held on 10 successive nights and culminates in the morning of the fullmoon day of Esala. The pageant symbolises rain: it is led by whip-crackers representing the sound of thunder, followed by the torch bearers and fire jugglers, symbolising lightning and finally by elephants who are the rain clouds. It is a magnificent ceremony and the whole procession takes at least two hours to pass. On the morning of the fullmoon day, lay-priests ‘cut’ the water of the Mahaweli Ganga and then return to the Temple with caskets of fresh water. Buddhists believe that it rains on the day of this water-cutting ceremony and, after the first three weeks of the Fellowship in the dry heat, that morning it rained for some five hours non stop! The Pali line, ‘devo vassatu kalena (may gods give rain in due season) is recited everyday. The word devo can mean either god or rain cloud and for people engaged in agriculture is there a god higher than a rain cloud? (4) The Tank Systems The rural life was made possible at this time by conserving rain in artificial ponds and by creating stone dams across rivers or streams and leading the water along channels to the fields under cultivation. There are innumerable examples of these village tanks still irrigating fields below their embankments by gravity distribution. The Topographical Survey of Ceylon 1904, recorded 11,200 in Anuradhapura District and Northern Province alone. They were called wewa (Sinhala) or kulam (Tamil). The Portuguese had referred to them as tanques meaning lakelets but the British converted this term to the inelegant word ‘tank’which does little justice to these beautiful waterbodies.(2) The bunds (we-kanda in Sinhala) were grass covered earth banks from 1/8th to half mile long, 12-14ft high with 1:2 slopes. There is a freeboard of a few feet which is maintained by a spillway - vaan - generally sited at one end of the bund and the impounded water is conducted to the fields by a channel or ela running from an outlet taken under the bund, called a horowwa. Acknowledging that the first reservoirs were created in the Euphrates valley some 4000 years BC, Brohier maintains that it was only in Sri Lanka that the fusion of Babylonian and Egyptian patterns took place(2). In the first century AD, the small village tank progressed to the major tank created by the cooperation of several villages for their construction and maintenance. The weaknesses of the village tanks were that, in times of heavy rainfall, water would overwhelm the bunds and cause a breach and consequent flooding, and, secondly that in dry weather up to half the capacity would be lost to evaporation. By the first century AD, the move away from these small tanks is recorded: deeper valleys were selected for the siting of tanks, the bunds were up to 30ft in height and up to a mile long. The shoreline rose to 3 miles and the cultivable area increased from 50 acres to over 500. However, by the third century AD the bunds were 50ft high and, as in the case of the Minneriya tank which has remained in existence to this day, submerged 4000 acres, could irrigate 6000 acres and would still be capable of irrigation supply after an absence of rain for 2 years. The land beneath the embankment was divided among the people according to a complex system but resulted in farmers’ sharing the best and worst land equally. The zenith of tank building was reached in the twelfth century. King Parakrama enlarged many existing tanks and at Polonnaruwa created the Parakrama Samudra with a dam 9 miles long, 50ft high and covering 5000 acres. It is estimated that with an earthwork of some 4.5 million cu.yds, it would have taken 1000 men 12 years, working 24hrs a day to complete. (2) It was the dual role of the rulers to first provide temples for the spiritual welfare of the people and then to create reservoirs for the growing of rice and vegetables. After Parakrama’s death in 1186, invasion from southern India led to Polonnaruwa being abandoned in 1214 AD and the seat of government moved around the country until settling in Kandy in the 1350s. The tank system was no longer maintained and was largely disused even during the period of Portuguese occupation from the 16th century. When the Dutch East India Co. arrived in the mid 17th century they attempted to resurrect the production of paddy – in order to benefit from their 10% taxation. The British again allowed the systems to fall into disuse until Sir Henry Ward became Governor in 1856 since when the tank systems have been maintained and developed. I visited a number of systems from traditional to modern to see how they had developed and were operated. It was not my aim to understand the complexities of current day water distribution in Sri Lanka but rather to study the extant traditional systems. Walawe In the south of the country the Walawe river basin covers an area of some 2400 sq km from the central highlands to its mouth near Hambantota on the south coast of Sri Lanka. Hundreds of small irrigation tanks constructed in ancient times are scattered throughout the catchment. In the early 1960s the government decided to develop the basin for irrigation and hydropower and in 1963 started the construction of the Uda Walawe dam, completed in 1976. There was intense debate about this scheme and some (eg D L O Mendis) maintain that it was a) built in the wrong place and did not exploit the catchment potential and b) destroyed many local tanks and irrigation systems. His view (pers comm. 17/8/06) is that, if it had been constructed further upstream the existing systems could have been retained, increasing the areas available for paddy and other field crops. (the Left Bank extension project, representing the future of water management in Sri Lanka is described in Section 5). Mahaweli – Victoria Dam In the 1980s, based on advice and studies by British engineers, the Victoria Dam was built. It is a concrete arch dam 122m high and 507m along it crest. It was opened by Mrs Thatcher in 1985. This created the Victoria Reservoir which flooded the Mahaweli ganga valley requiring the relocation of 80,000 villagers and the loss of fertile bottom valley land. This was also a controversial scheme and representations were made to the World Commission on Dams during their investigations during 1999/2000. The Commission concluded that no more schemes should be promoted that had the effects on the environment caused by Victoria: loss of Victoria Falls with too much of the water being taken for energy with no overflow resulting in the virtual disappearance of the river. However the stored water is used for the generation by hydropower of 40% of Sri Lanka’s total energy requirements. The water is then discharged downstream where it is fed to other reservoirs in the Mahaweli system for wider distribution in the north of Sri Lanka for treatment and potable use. I met with Chief Engineer, Mr Aruppola, and discussed the performance and effects of the dam. He then arranged for me to be shown the dam, its galleries and spillways by his staff. Parakrama Samudra The Parakrama Samudra built in the 12th century has been provided with a modern sluice system to protect the embankment and to control flooding. It still works in the way originally intended – to store water during the rainy season and to provide water for crops during the dry season. Matale This town of some 80000 people lies in central Sri Lanka between the wet and dry zones on the main road from Dambulla to Kandy. I was the guest of Mr Zafarullah, Member of the Municipal Council, and the Vice Mayor Mr Jayasekara. The drinking water supply for the town is a fairly conventional 1970s system: water is abstracted from the river upstream treated at the treatment works (settlement, flocculation using alum) and then pumped to the service reservoir for distribution to the town. Drinking quality water was first provided to the whole population in the 1980s at a cost per cum. However the poorest people are also able to use the public baths free of charge for washing and bathing. These are what interested me and Mr Zafarullah (a member of the International Water History Association) most. They are fed by natural good quality springs but unfortunately the facilities for the users (segregated men/women) are rudimentary. The Council is seeking funds to provide changing and drying facilities and I have subsequently approached Wateraid in the UK to see if they can help (see Section 7). Kandalama Similar to Parakrama Samudra, the region around Dambulla is served by a number of large tanks and canals which have been developed from the ancient systems. Of particular interest was Kandalama Tank (wewa) which was developed in 1951, shallowly submerging and extending some ancient tanks. The water is led via canals to irrigation systems where paddy and vegetables are grown. Anuradhapura The area around Anuradhapura has an intense concentration of the cascade system of tanks and I visited several with Dr Bandaranayake and Mr Sumanajith from the Department of Geography at Sri Jawadanapura University. Typical is the Alistan wewa which was restored in 1971 and provides irrigation sufficient for two cultivating seasons per year. 85 village families are supported by this shallow tank which has a dam 1 mile long and contains 40 acre/feet water. They grow paddy and soya beans. Cultivation meetings are held twice a year when the Agrarian Research Officer advises on the area of land that can be irrigated. One villager - the wellvidane - appointed by the village, operates the sluice. The tank is used for bathing, washing and animal husbandary as well as irrigation (drinking water is supplied from the Mahaweli scheme - see above). The dam construction is quite simple with no constructed core it comprises alternate layers of clay and clay/sand. Typically small tanks are 3 acres in area and irrigate 8 acres. We also saw the Pansala wewa tank at Maradankadawala whose bunds were being repaired and raised by 1 foot using local clay. While in this area we also visited the 10th century Nachchaduwa Tank which stores water from the Malwath Oya which feeds Anuradhapura. This was restored in 1906.
Literatur Bearbeiten
- Nilan Cooray: The Sigiriya Royal Gardens: Analysis of the Landscape Architectonic Composition. Architecture and the built environment, Bd. 6. ISSN 2212-3202; TU Delft 2012: 102 ISBN 148003097X, 9781480030978
- Peter P. Mollinga: On The Waterfront: Water Distribution, Technology And Agrarian Change In A South Indian Canal Irrigation System. Orient Blackswan 2003: 437. ISBN 8125025073, 9788125025078
- Winston Churchill Travelling Fellowship - Traditional Water Management in Sri Lanka & its relevance to the UK for Climate Change. Report to Trust. Trevor Turpin, Fellow 2006 S. 5
- Nandasiri Jasentuliyana: Same Sky, Different Nights AuthorHouse 2016. ISBN 1524600415, 9781524600419
Weblinks Bearbeiten
- Traditional Water Management in Sri Lanka & its relevance to the UK for Climate Change. Report to Trust. Trevor Turpin, Fellow 2006.