Kuda Vilachchiya Wewa and its Ruins inside Wilpattu

The massive bisokotuwa of Kuda Vilachchiya before destruction by treasure hunters — The massive bisokotuwa of Kuda Vilachchiya before its destruction by treasure hunters
Photo by Badra Kamaladasa

Kuda Vilachchiya Wewa in Wilpattu features Sri Lanka’s largest ancient Bisokotuwa (water-control sluice), built around 2,000 years ago. Its intact stone riprap, twin sluices, and spillway demonstrate exceptional early engineering, though the remote site suffered significant damage from treasure hunters in 2013.

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The Ancient Bisokotuwa of Kuda Vilachchiya Wewa

The Bisokotuwa was a remarkable invention of ancient Sri Lankan irrigation engineers, who played a significant role in the development of the island’s civilization approximately 2,300 years ago. This unique water-control structure regulates the water levels in reservoirs and has been constructed in Sri Lanka since at least the 3rd century BCE. Its introduction was instrumental in ensuring the longevity of the island’s extensive irrigation reservoirs, many of which have survived for thousands of years, making the Bisokotuwa an important element of Sri Lanka’s historical and engineering heritage.

The largest and best-preserved example of this structure is found at the relatively little-known Kuda Vilachchiya Wewa, located within Wilpattu National Park in the Modaragama Aru (Wila Oya) basin. Although the reservoir was abandoned, left without maintenance and eventually became almost unrecognisable, its ancient embankment and massive Bisokotuwa have survived for nearly 2,000 years, undisturbed beneath the dense jungle within the National Park until treasure hunters destroyed it in the recent past.

The embankment of Kuda Vilachchiya Wewa extends for approximately 2.5 km, making it longer than that of Maha Vilachchiya Wewa. Irrigation officials in Anuradhapura believe that early surveyors may have confused the names of these two reservoirs, an error that has continued to the present day. The embankment of Kuda Vilachchiya shows evidence of breaches at seven locations.

Both Maha Vilachchiya Wewa and Kuda Vilachchiya Wewa are believed to have been constructed during the reign of King Wasaba (67–111 CE). However, another theory attributes their construction to Prince Saliya, son of King Dutugemunu (161–131 BCE), around 140 BCE.

Since the reservoir is situated deep within the jungle of Wilpattu National Park, an area inaccessible to the general public, survey teams must first obtain permission to enter the park. They then travel by tractor as far as possible before completing the remaining journey on foot.

The Embankment and Riprap Construction

The carefully laid stone riprap (ralapanawa) on the upstream slope remains remarkably intact despite decades of abandonment and the movement of elephant herds through the National Park. Another notable feature of the upstream slope is the incorporation of a berm, which provides additional stability. This is a relatively rare design feature employed by ancient engineers, particularly in sections of high dams. The precisely dressed rubble used in the riprap indicates that a large and highly skilled workforce must have been involved in its construction, as each stone block was carefully shaped to fit into its designated position.

The Bisokotuwa Structures

The two Bisokotuwa structures are equally impressive examples of ancient engineering. The stone slabs forming their inner surfaces fit together with remarkable precision, leaving virtually no gaps through which plants could grow, even in the surrounding dense jungle. The outer covering of the sluice towers was constructed using bricks, while the inner stone slabs remain intact. These features demonstrate the exceptional craftsmanship and technical expertise of the engineers who built these reservoirs.

The Ancient Spillway

The ancient spillway is another outstanding example of the engineering capabilities of Sri Lanka’s early irrigation builders. The villagers refer to the wing wall and the backfilling section as the Paththirippuwa, believing that this may have been a resting place for Prince Saliya and Asokamala. The location offers magnificent views of the spillway and the reservoir, and some believe that it may also have served as an official meeting place. The surviving spillway measures approximately 15 m in length.

An inscription found at the spillway, dating to the 16th century, bears the phrase “Kusaya Buduwewa”, meaning “May Kusaya attain Buddhahood”. There have been proposals to restore the headworks under the guidance of the Department of Archaeology, while carefully preserving their original features. Such an approach would allow future generations to observe the ancient spillway and sluice structures without compromising their historical authenticity.

Another distinctive feature of the headworks is the conveyance channel extending from the sluice outlet. This channel was constructed as a closed conduit using stone slabs. Until the archaeological and engineering surveys are completed, however, it is difficult to establish the precise reason for adopting this particular design.

Vandalism and the Present Condition of the Ruins

The survey and site visit described above were carried out around 2011. However, in December 2013, reports emerged that this unique Bisokotuwa had been vandalised by treasure hunters. According to these reports, the perpetrators had established a camp at the site for more than a month and used machinery to remove the massive stone slabs from the structure.

The reported ability of the perpetrators to conduct such an extensive operation raised suspicions about possible involvement by powerful political figures within the government. Nevertheless, no conclusive evidence or significant progress in the investigation has been made public. Consequently, the present condition of these important archaeological remains remains uncertain.

Part of the rip -rap of the Kuda Vilachchiya Tank

Paththiripuwa Ruins near Kuda Vilachchiya Tank

A 16th century inscription at the spill of the Kuda Vilachchiya Tank

References

Brohier, R. L. (1935). Ancient Irrigation Works in Ceylon : Northern and Northwestern Sections of the Island: Part II. Government Publications Bureau (Ceylon).
Kamaladasa, B. (2026). Irrigation Heritage of Sri Lanka (1st ed.). The National Trust Sri Lanka.
Mahaweli Authority of Sri Lanka. (2017). හෙළ වාරි පුරාවත : ආරම්භයේ සිට වර්තමානය දක්වා ශ්‍රී ලංකාවේ වාරි සංස්කෘතිය පිලිබඳ විවරණයක්: Hela Wari Purawatha : Research Program on Sri Lanka’s History of Irregation from the Begining to Modern Times. Mahaweli Center, Sri Lanka.

Also See

ලංකාවේ ලොකුම බිසෝ කොටුවටත් හොරු බැටේ දෙති

Traveling Directions to Kuda Vilachchiya Wewa and its Ruins

From Colombo to Wilpattu National Park entrance gate	From Anuradhapura to the entrance gate of Wilpattu National Park
Via : Negombo – Puttalam Total Distance : 190 km Duration : About 3.30 hours + 1-2 hours to walk into the forest Duration : 1-2 hours approx Driving Directions : View on Google Maps	Total Distance : 40 km Duration : Around 45 minutes + 1-2 hours to walk into the forest Duration : 1-2 hours approx Driving Directions : View on Google Maps