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As unbelievable as it may seem at times, Sri Lanka is faced with many obstacles relating to the quantity and distribution of its water resources.

Highly seasonal and special variations in rainfall have initiated a history of innovative and successful irrigation schemes. Historically tanks (reservoirs), irrigation canals and paddy fields have been connected in perfect harmony, allowing the successful distribution of water on both national and regional scales. The system contains innumerable examples of engineering triumphs, such as the gigantic Parakrama Samudra and Kalaweva reservoirs and the irrigation marvel of the Minipe Ela, which is constructed with an inconceivable gradient of six inches fall per vertical mile.

One type of irrigation system, which is not generally cited amongst the nation's irrigation success stories, is the underground irrigation canal, locally termed a Bhoo Ela.

The tunnel in question was constructed in the highlands of the central mountains of Sri Lanka, as early as 1350 AD, to divert the westbound flow of the Dambagastalawa Oya to the Uma Oya basin, which lies on the eastern side of the central ridge.

Details regarding the nature of the scheme were presented to the Royal Asiatic Society in Colombo on Monday, by Mr. Sudath Gunasekara who studied Geography at Cambridge University, before working for the Sri Lanka Administrative service.

Mr. Gunasekara is a layman in the field of structural and hydraulic engineering, and his involvement with the Bhoo Ela resulted from sheer enthusiasm in his retirement years. William Hall, the engineer who rediscovered this novel scheme in 1857, provided the most complete account of the Bhoo Ela in existence today.

The date of construction is largely speculative, but corresponds with the upward migration of our forefathers into the uplands in search of water, which was essential for the survival of civilizations in the lowlands.

Mr. Gunasekara described the scheme as "a wonder of engineering skill and imagination." Justified praise when one considers that the scheme, with a maximum altitude of 2133m above sea level, is the highest project of its type ever to be discovered in Sri Lanka. When one considers that the tunnel, 221meters in length and 3.48 meters in diameter at the time of its discovery, is self-supporting beneath a 12-meter overburden, it is clear that it is a remarkable achievement of design and construction. In addition to the staggering statistics, Mr. Gunasekara explained that it was constructed without any environmental consequences, a factor which blights many contemporary hydraulic structures.

Mr. Gunasekara proceeded to explain that the design, surveying and construction defied the technology available at the time of construction.

The construction of the mountain railway caused the destruction of a section of the scheme, however, enough remains preserved for the scheme to retail interest from contemporary hydraulic engineers.

The statistics of the scheme are very impressive and Mr. Gunasekara presented his account with great enthusiasm, but for non-specialists in this rather specific area, it may appear to be a little more that an old hole in the ground. Mr. Gunasekara defends this accusation with vigour.

"The scheme is a great example of the evolution of engineering technology, and in Sri Lanka we have a great heritage in such things," Mr. Gunasekara explained. Indeed, the Sri Lankan hydraulic technology is the envy of the world. "Despite a history of success, we are increasingly looking to the west for ways to develop our irrigation systems," Mr. Gunasekara continued.

"However, the only way to develop a sustainable irrigation system on a national level is to learn from past successes on the home front." Mr. Gunasekara called upon peers, technical experts and enthusiasts to assist him in gaining further knowledge about the scheme.

"A great deal remains to be discovered about the scheme. I would like to reach anybody with specialist knowledge to contact the Royal Asiatic Society and join me in future field investigations," he said.

It would appear to be a great opportunity for any person with an interest in the subject, whether you are a youngster, looking to gain research experience or an experienced professional, who could offer extensive guidance.

Matters in urgent need of consideration are a geological survey and interpretation of the sub surface features. Boreholes or geophysical surveys are the logical next step in the exploration process.