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Surviving without surface freshwater

What climate change experts can learn from Palau's early colonizers

By Raquel Bagnol

Ulong, a major island and channel of western Palau, is regarded as Rock Island’s most significant archeological treasure that tells of human history spanning over 4,000 years. Scattered ceramic pot shards portray the idyllic life of early Micronesians.

Two ceramic pots with missing bottoms excavated from Ulong, which is bereft of surface freshwater, gave archeologists and cultural researchers a glimpse of the early colonizers’ survival skills.

Water resources played a big factor in the human colonization of the Pacific islands. Early colonizers in Micronesia typically avoided islands that had no surface freshwater.

Besides being plagued by a lack of freshwater streams, Ulong’s environment is harsh with very steep topography and infertile soils.

Archeological discoveries provided clues to how the early settlers adapted to their environment by innovating a system of collecting freshwater.

In 2012, a team of researchers from the Australian National University and the Bureau of Arts and Culture Palau, Conservation and Coastal Management Division of Koror State dug up the pots during an excavation trip in Ulong.

Researchers Christian Reepmeyer, Geoffrey Clark, Jolie Liston and Ella Ussher published a paper suggesting that the pots, dated around 2800 cal. BP, were from the early colonization phase of Palau’s Rock Islands.

Researchers theorized that the early settlers used the pots for collecting fresh water to survive. There were indications that the pots were initially used for cooking, then possibly recycled as storage containers.

The ceramic pots at the Ulong site were placed deliberately on dry to semi-dry sand. The researchers discovered that when the tide rose, freshwater seeped up from the spot where the pots rested.

Earlier studies in 1999 showed that even in the absence of surface freshwater in Ulong, "the porous bedrock allows rainwater to percolate through the limestone to accumulate on the saltwater intrusion layer to form the Ghyben-Herzberg lens. The accumulated freshwater then builds up as a lens that float on the heavier saltwater that rises and falls with the tidal fluctuations of the underlying seawater."


Despite the harsh conditions in Ulong, small, mobile groups occupied the island around 3000 cal. BP, using it as a short-term camp while they harvested marine resources from the adjacent reef. Permanent settlement only happened after the stabilization of the beach flat.

Colonizers abandoned Ulong about 400 cal. BP.

Without surface freshwater in the islands, liquid storing plants, such as coconuts, were important for the early colonizers.

A 2003 study determined that a population of 25 to 50 people needed 525 to 1,050 liters of water per week. This would quickly deplete the plant resources of an island.

Coconuts grew in Babeldaob island, but in Ulong, coconuts did not grow in large quantities until the beach flat was stabilized and expanded in the past 2,000 years.


Early Palauans reported traces of village life, but the early settlers abandoned the Rock Islands during the 16th century with the onset of the “Little Ice Age” in the western Micronesian region. The Little Ice Age was the period of a significant decrease in overall precipitation between AD 1250 and AD 1650.

Rock Islands, a UNESCO World Heritage property comprising 300 small limestone islands, are among Palau’s most attractive sites that draw thousands of visitors from all over the world.

The beautiful islands remain uninhabited because their environmental conditions are not suitable for human habitation. But the fact that early settlers survived Ulong’s harsh conditions and lack of freshwater was a testament to their ability to confront and overcome obstacles.

Raquel Bagnol is a freelance journalist. She previously worked for Palau Horizon and Marianas Variety. Send feedback to

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