The Irasiquero River leaves the largest freshwater lake of Timor-Leste – Irasiquero Lake – and flows towards the nearby sea. This would be geographic triviality if… the river would not disappear underground in the impressive Mainina Ponor after making half of the distance to the sea.
Map of the site
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Iralalaro Lake resembles a 6.5 km long scar in the mountainous forestland in the eastern tip of Timor-Leste. The area of the lake is changing according to season and weather conditions – from 10 to 55 km2. In this area, bedrock consists of carbonates (e.g. limestone) and there are ongoing intense karst processes. Lake itself is an enormous karst depression – polje – and there are known numerous caves, sinkholes, ponors, and other karst phenomena around it.
Irasiquero River and sacred ponor
The only surface outlet from the lake is the Irasiquero River. It is true that this river flows exactly towards the 9 – 10 km distant sea – but there is an impressive mountain range – Paitchau Mountains – in between. After flowing for some 4.5 – 5 km the river reaches a ponor at the foot of mountains – and the stream with a roar disappears in a swallet which is less than a meter in diameter. Every second here flow 5 – 30 m3 of water.
The sea still is some 4.5 km far away. There have been done experiments with a dye tracing in Mainina ponor – the dyed water appeared in several springs on the other side of Paitchau Mountains (up to 975 m) – but also in faraway springs closer to the northern coast of Timor-Leste. This looks like a hint at the existence of an enormous underground cave system.
Diving into swallet is very dangerous – the stream is very fast and powerful even in the dry season. The bed of the ponor does not have any forest – at wet season here forms a lake which might be up to 20 m deep.
Local people consider this to be a sacred place.
Dry tropical forest
Mainina ponor is located in a unique, primeval forest – the largest remaining dry tropical forest of Timor-Leste. In this unique forest have been found new species of animals, such as turtle Chelodina mccordi timorlestensis (described in 2007 and living in the wetlands around the lake) and hardyhead fish Craterocephalus laisapi, living only in Irasiquero River.
Plans of hydroelectric power plant
Timor-Leste has a shortfall of electrical energy production facilities. There has been proposed to divert part of the water from Iralalaro Lake to the underground power plant through a 4 558 m long underground pipeline.
Closer investigation shows that the realization of this idea is very complex. Construction of tunnels through carbonate rocks nearly always brings unpleasant surprises – enormous voids, underground streams, and flash floods. Construction works might bring also changes to the hydrological regime of this region, construction of new roads will dissect the primeval forest.
- White, Susan; White, Nicholas; Middleton, George; Report of Findings on the Proposed Iralalaro Hydro-Electric Power Scheme, Timor-Leste, January 2006. Accessed in the 22nd May 2011
The island country of Timor-Lest has magnificent scenery, interesting geological attractions, rich biodiversity, and promising archaeological finds. This country is rather little known and in the future, there are expected more discoveries.
This category includes outstanding sinkholes – large natural depressions or holes, which for most the part represent collapsed caves.
Any other continent (and part of the world) seems small if compared to Asia. This refers also to natural and man-made heritage: in Asia are not just thousands of great landmarks, there are found landmarks created by thousands of diverse cultures from ancient Phoenicians to the mysterious small people in the Philippines and eastern islands of Indonesia.
The Democratic Republic of Timor-Leste, a former Portuguese colony occupied by Indonesia from 1975 to 1999, became in 2002 the first new sovereign state of the twenty-first century. Its modern nationhood belies its ancient history. Archaeological data found on the island can be traced back at least 42,000 years, beyond most ancient European artifacts. The book provides an engaging overview of the history of the country from the earliest legends and first traces of human habitation through the defining events that led to independence.
This volume brings together a collection of papers from a diverse field of international scholars exploring the multiple ways that East Timorese communities are making and remaking their connections to land and places of ancestral significance.