The ancient hydraulic civilization of Sri Lanka
By A. Denis N. Fernando,
Irrigated technology in Sri Lanka existed here before the advent of Vijaya when she was occupied by indigenous Veddhas as well as Seafearers and Traders namely the Yakkhas who were sunworshippers who had a Persian connection. While the Nagas had a Red Sea Erythrien connection who were snake or naga worshippers and great builders. The oldest city of Vijithapura indicated in the Mahavamsa as having 3 moats, the remains of which are clearly indicated in the aerial photographs and located between Kaduruwela and the new town of Polonnaruwa.
7. The map showing the distribution of the different type of Ancient Irrigation Structures; indicates ancient canals from Yakabendi elas that provided irrigation from the Mahaveli Ganga like the Kalinga and Gomathi elas; while we had canals like the Yoda elas that took water from the Kala Oya to Anuradhapura by a canal having a gradient of half a foot to the mile which even today with modern technology is difficult to achieve. Then we have the ancient Maduru Oya sluice which I discovered in 1981 which had two sluices and built in three stages starting from the BC period. According to the Mahavamsa the Yakkhas had their annual new year (sun festival) at the Dolapabbatha even in the time of King Pandukabhaya which lies between the Maduru Oya and the Mahaweli Ganga indicating the antiquity of this region in the BC period, which area was occupied by the pioneers of irrigation technology in Sri Lanka.
8. While the distribution of the major reservoirs were in the Intermediate and Dry Zones. It must be mentioned here that there were no major reservoirs on the main Mahaveli Ganga as the ancients used the profuse base flow of the river to divert water using diversion canals to major reservoirs located elsewhere. It must be mentioned here in the time of the Parakramabahu I in the 12th century had cultivated more land than is now done under the present Mahaveli Project with large reservoirs on the main Mahaveli Ganga to capture the flood waters as today the base flow is small that was caused by the deforestation of the Upper Catchment.
The distribution of high density minor irrigation reservoirs is concentrated in the Intermediate Zone, while low density minor irrigation reservoirs are located in the Dry Zone. As the water resources available in these catchments are small, only about half of these tanks could be in operation at any one time. The ancients in their wisdom used them in cyclic rotation to recuperate their fertility by allowing the paddy fields under them to be in fallow alternatively. Todays attempts to rehabilitate all these minor irrigation reservoirs by solving the problem of fertility using inorganic fertiliser would fail because of the shortage of water resources. Therefore the restoration of all minor irrigation schemes would not help the farmer but will only bring misery to him which the bureaucracy do not understand. More of this could be referred to is the special issue of RAS Journal on The Ancient Hydraulic Civilisation of Sri Lanka.
The fall of the ancient hydraulic civilisation of Sri Lanka in the 13th century was due to sudden Natural Cataclysmic change of the river course of the Mahaveli Ganga and was not due to foreign invasions as historians would want us to believe. The scientific evidence is clearly seen in the aerial photographs of the old course of the Mahaveli Ganga and its new river course. The ancient Mahaveli with its ancient chaityas which were beside the old river like a string of pearls now lay stranded beside it. While the present river flows elsewhere with no chaityas beside it which event took place in circa 1220 AD. This sudden geological catyclysm that changed the river course that sustained our ancient hydraulic civilization, led to disease and famine. This resulted in the major part of the population to abandon these areas and move to the Wet and Intermediate Zones where the king also established himself at Dambadeniya, Kurunegala, Gampola, Kotte and Kandy.
9. With independence the revival of our ancient hydraulic tradition to construct large irrigation reservoirs began with Galoya, Walawe and finally Mahaveli Ganga, rehabilitating our ancient canals and reservoirs while also building new large dams built across the Mahaweli Ganga for the first time which did not exist before to capture the flood waters to resettle our people in the land of their forefathers.
10. Finally we must be warned that if the bureaucracy does not take the advise of our scientists, being penny-wise and pound foolish by not providing the necessary funds to purchase and replace disfunctioning monitoring scientific instruments to monitor the high dams as done in our neighbouring countries, a disaster can happen. The safety of our large dams especially in the high elevations have to be ensured. If not we would in the near future may be without any warning have to face a man made national disaster which could be worse than the one that took place in the 13th century due to natural causes. If any of our high dams in the higher elevation fail without warning it would result in the reservoirs below them falling like a pack of cards which would end our Mahaveli civilization, built at great cost.