Polynesian Plumbing

Rapa Nui, a.k.a. Isla Pascua, a.k.a. Easter Island

I visited Rapa Nui in October, 2024, whan an annular eclipse of the Sun crossed the island.

Yes, the island is named Rapa Nui. English speakers tend to call it "Easter Island". A Dutch explorer was the first European to notice it, arriving on 5 April 1722, Easter Sunday, and he called the island Paasch-Eyland. That's 18th century Dutch for "Easter Island". Chile took control of the island in 1888 and called it Isla Pascua, Spanish for "Easter Island".

However, people had arrived on Rapa Nui from Polynesia some time between 300 and 800 CE. It's a very isolated island, but the Polynesians were phenomenal open-water navigators. The people who settled here established a tradition of carving mo'ai, large statues depicting deified ancestors. The mo'ai are today's common image of the island and its culture.

Europeans brought diseases and unwanted attention that led to slave raids from Peru. That led to the nearly complete genocide of the Rapa Nui people, and the erasure of their culture during the 1860s to 1880s.

By 1877 the population had dropped to just 110 people. All Rapa Nui today are descended from just 36 people who lived through that population bottleneck and had children.

Rapa Nui is remote due to sheer distance, isolated due to foreign commercial control in the late 1800s into the 1900s followed by Pinochet's 1973–1990 junta and martial law, and exotic enough to attract crackpot theories that obscure facts.

In the 2020s, when I visited, the Rapa Nui people were still struggling for control of their home.

The result of a century and a half of Chilean control is that Rapa Nui toilets and other water-handling systems are now much like what you find in Chile. Or at least they're catching up to that. As of 1996 there was still no sewage treatment on the island.

The island of Rapa Nui is the peak of a volcanic mountain that rises over 2,000 meters from the sea floor. What protrudes above the ocean are the coalesced peaks of three extinct volcanos. Rano Kau, rising 324 meters above the sea, is at the southwest corner of the island. overlooking the island's single-runway airstrip. Poike, 400 meters tall, is at the eastern tip. Terevaka, the tallest at 507 meters, is near the center.

The island is roughly triangular, about 23 kilometers east–west and 11 kilometers north–south. Most everyone in the population of almost 7,800 people lives in the town of Haŋa Roa, at the base of the 324-meter Rano Kau volcano in the southwest corner. That's because British sheep ranching firms took control of most of the island, banishing all its inhabitants into this small corner through most of the 20th century until 1966.

The island is known for its mo'ai, megalithic statues of deified ancestors. They're often referred to as "heads" because many of the pictures show partially-buried examples. However, they include arms and torsos down to the groin.

The mo'ai are placed on ahu, stone platforms that evolved from the traditional Polynesian marae, communal or sacred spaces.

Most of the ahu and their mo'ai are placed along the coastline with their backs to the spirit world in the sea, watching over their descendents. Ahu Toŋariki, seen here, is the largest ahu holding the largest examples of mo'ai. The second one from the right wears a pukao, a hat-like cylindrical structure carved from light-red volcanic scoria and believed to represent the long hair of high-ranking men tied in buns on top of their heads.

At My Apartment

You can't just casually show up on Rapa Nui. Access is via a daily 5.5-hour, 3,750-kilometer LATAM flight from Santiago, and to access its concourse you just pass through a variant of border control, showing that you have a return ticket and a reservation at a guesthouse corresponding to Chilean border control records.

Your innkeeper will be at the airport to present you with a lei and drive you to your lodging. I stayed at Hostal Henua Roa, where I had a nice apartment with a small kitchen. It's just over a kilometer from the fishing port, with an elevation gain of 50 meters.

The tap water is brackish. Not as brackish as the incompletely desalinated tap water you find on Greek islands, it's OK for making tea or getting a quick drink in the night, but it's a short walk to the road and then down a hundred meters to the shop with bottled water.

Here's the toilet and shower in the bathroom.

Notice the waste bin beside the toilet. Just as in "continental Chile", toilet paper goes into the bin and not into the toilet.

The toilet had a small lever on the front of the tank for flushing. I noticed the same thing that's common in Chile — if you briefly press the lever and release it, the flushing action stops almost immediately.

In Local Cafes

These have the common dual-flush split button, for a small or large flush.

And how do you tell people to throw used toilet paper into the waste bin and not into the toilet in the Rapa Nui language?

The Rapa Nui language was heavily influenced by Tahitian through the second half of the 19th century, when the population crashed and many people were relocated to French Polynesia before being returned. We think that the original settlers called the island Te Pito 'o te Kāina, meaning "The Center of the Earth". The name for the people, their island, and their language became Rapa Nui after their language had become heavily influenced by Tahitian. The number of fluent Rapa Nui speakers is now down in the hundreds.

At a Waterfront Park

A nice park extends north along the waterfront from the center of town. It includes this retaining wall and two toilet facilities, built from the local volcanic basalt.

How do you say "Men's" and "Women's" in Rapa Nui?

At the National Park Office

Once you arrive on Rapa Nui, you're free to explore town, where there are some ahu and mo'ai. However, you can't simply leave town and wander around the ancient sites on your own.

First, you need to buy a National Park pass.

Second, you have to get a qualified and licensed local guide. Your innkeeper may know a "companion", someone who is qualified but can't speak your language. And then you would need your own rental car.

I did an all-day trip with Hahave Rapa Nui and was very pleased with the experience. There were 12 of us in the group. We left at 09:00 and spent the entire day visiting six sites, not returning until almost 18:30. Emilia Tepano, our guide, was excellent, and the day's itinerary was well planned. Having designed, written, and presented one-week training courses, I appreciated the tour's plan and Emilia's presentation. Emilia is fluent in Spanish and English, speaking both rapidly in the Chilean fashion, and explained everything in both languages at all the sites.

You set up your tour in person or perhaps through your guesthouse. First, though, get your pass at the National Park office near the Tourist Information office. The back of the building has a pair of public restrooms, one for the disabled and one not.

Rano — Traditional Water Supplies

Rapa Nui is a volcanic island. It was formed when lava came up out of the sea bed, built up, and eventually broke the surface. Water, however, does not come up out of the Earth.

And, as an island in the south Pacific, it is surrounded by thousands of kilometers of utterly undrinkable sea water.

However, the Polynesian people who settled here came from similarly formed islands, and knew what to look for.

Rano is the Rapa Nui term for a lake in a volcanic caldera. The lakes within the volcanic cones of Rano Kau, Rano Raraku, and Rano Aroi were crucial for human settlement, and remain the primary source of drinking water. There are no other lakes on the island, nor are there any large streams.

Rano Raraku, a smaller volcanic peak, is a short distance inland from Ahu Toŋariki, beyond the lone mo'ai in the pictures below. Rano Raraku was the main mo'ai quarry and workshop, where the statues were carved from layers of tuff, lithified volcanic ash.

What western scientists had only figured out a few years before my visit was that rainfall collected in the rano can escape through thin crevices, and then flow between gently sloping lava layers from the volcanic cone to the coastline and into the ocean.

A stretch of shoreline no more than ten meters long might have fresh water instead of salty from the waterline out five to ten meters.

The climate was somewhat unfriendly — they had traveled from tropical islands, carrying tropical vegetables, to a subtropical island. The climate's limit on their food supply, plus the limited water supply, combined to strictly limit the population.

Western researchers, until very recently, chose an assumed population density and then calculated a total population in the tens of thousands. However, the climate and freshwater supply meant that only a fraction of that number could survive. The first European visitors did not report such a number. And so, the western researchers concluded that obviously there must have been a population explosion followed by a famine, with that leading into some mix of multi-year vicious inter-clan war and cannibalism.

Jared Diamond has done a lot of field work in Papua New Guinea, so he tends to see cannibals wherever he looks. He interpreted the existing records of Rapa Nui oral traditions, which many researchers strongly doubt are truthful, as showing that the recent and current islanders are obsessed with cannibalism, and that the cannibalism was part of their society's collapse.

Cannibalism has been widespread across Polynesian cultures. However, on Rapa Nui, the only human bones found in earth ovens have been behind the ahu, the religious platforms, indicating that it was only a limited ritualistic practice. And, recent studies of bones show that only a very small percentage of human bones show signs of damage that would result from the supposed widespread violence, and outside the ritual earth oven locations, none have shown signs of butchering.

As for the claims of a current obsession with cannibalism, many outside researchers visiting Rapa Nui have used repeated, leading questions, continuing and suggesting until they get a pleasingly lurid answer.

As for claims of inter-clan warfare causing a population crash, studies of bones show fairly low occurrence of severe injuries, no higher during the purported times of warfare than at other times.

Some further studies of genetics, anthropology, and archaeology were published shortly before I started my trip to Rapa Nui. They show that there wasn't an "ecological suicide", that there was no pre-European-contact population collapse, and that the Rapa Nui and probably other Polynesians reached the west coast of the Americas, picking up crops and having sex with the locals, long before even the Norse knew that the Americas existed.

There were never more than about 3,000 people living on Rapa Nui. Their agriculture was much more like gardens rather than farms.

Manavai is the ancient system of cultivation protected by a stone wall. The islanders may have gotten the idea by the microclimates formed by the volcanic calderas and their lakes. These agricultural features are at the Vaihū site.

The Rapa Nui people developed lithic mulching — covering plots of crops with small stones. It traps moisture, regulates soil temperature, and improves soil fertility. It has been independently rediscovered multiple times in dry areas of the premodern world, and now is used in vineyards in southern France and elsewhere.

Rano Kau — Traditional to Modern Water Supply

One day I walked around the west end of the airport and continued up the road to the rim of Rano Kau, overlooking town. I was fine with the 22 km distance for the day, but the 300 meter ascent to the crater rim and the descent back down left me pretty wiped out.

Rano Kau is a caldera, which comes from the same root as cauldron. A caldera is formed when a large lava chamber partially empties and then collapses, forming a broad flat-bottomed area surrounded by a ring wall, looking like a gigantic dish or cauldron. Here is the view from where I first reached the rim.

The caldera captures rainwater. The rano, the lake or lagoon, is about a kilometer and a half in diameter and about ten meters deep. Its surface is largely covered by floating mats of totora reeds, about one meter thick.

The lake within the Rano Kau caldera is about 100 meters above sea level, more than 200 meters below the highest points of the crater's rim.

Marine erosion over millennia has eaten away the southwest sector of the volcano, forming cliffs that drop 300 meters down to the sea.

That led to the formation of Kari Kari, a 400-meter-wide notch in the rim where the erosion and cliffs have slowly progressed inland.

Rapa Nui is on the Nazca Plate, which moves to the east about 150 mm per year above a volcanic hotspot or source of magma. That means that Poike, the peak forming the eastern corner of the island, is the oldest, and Rano Kau at the southwest tip is the youngest.

The hotspot is a source of basaltic magma, which has formed most of Earth's oceanic crust. The first eruptions forming Rapa Nui began about 2.5 million years ago. With Rano Kau being the youngest peak, what we see today as its volcanic cone developed over approximately 780,000–450,000 years ago. The last significant eruption was about 180,000 years ago.

So it's extinct, at least for now. In the early 1900s, when the island was controlled by an English sheep-farming company and the Rapa Nui people were forced to live within the town and work for the company, the English manager took a photograph that seemed to show steam issuing from the steep slopes around the caldera.

The interior slopes of the caldera are steep. They're about 45° at the lake shore and steepen to 65° near the rim.

Rano Kau has produced a great deal of obsidian. Pieces lie on top of the ground along the footpath on the caldera rim.

On Rapa Nui you mustn't carry away anything. But on Milos, in the Aegean Sea, there's no such rule and you're actually encouraged to look for obsidian. I saw smooth-surfaced black stones lying alongside a gravel track. I put some in a cloth bag and took them back to my room. That evening I was looking at them, thinking "These are supposed to be obsidian, but this doesn't look much like glass to me." And then I noticed that my fingers were bleeding.

Yes, this is what obsidian looks like. And it can be incredibly sharp.

The three large calderas shelter their interiors from the winds that blow across the rest of the island and maintain higher humidity, forming their own micro-climates. Figs, many vegetables, vines, and other useful plants grow within the calderas. Some are endemic to the island, others were brought by the settlers. Early settlements were established down in some of the calderas. An old settlement with a cluster of petroglyphs has been found down close to the edge of this lake.

The manavai, circular stone enclosures in which the Rapa Nui people maintained gardens, may have been based on the protective nature of the calderas.

Municipal Water Company

Finally, the municipal water company off the west corner of the airport, at the base of Rano Kau. They have a pipe to the Rano Kau aquifer, and pump the water to a hilltop tank in town.

After the annual eclipse, I got a locally brewed beer in a cafe along the waterfront road. Looking up the URL on the label, the Mahina microbrewery was close to where I stayed. That's it in the below picture, with the two tanks of the municipal water supply on the hill above it.

The brewery surely does some further treatment of the water.