May 12, 2016

Water in Yomibato: Guest post by National Geographic writer Emma Marris

I traveled last November to Manu Park in the Peruvian Amazon with writer Emma Marris to guide her among the Matsigenka people for a story she published this week in National Geographic. In this post from the science blog The Last Word on Nothing (reproduced with permission), Emma describes her visit to the water purification system recently inaugurated in this remote village by the charity organization Rainforest Flow.

Text: Emma Marris
Photography: Glenn Shepard

Durable, hygienic drinking taps, sinks and bathrooms were installed near the Yomibato village school by Rainforest Flow.
Last November, I went to the Peruvian Amazon on assignment for National Geographic.  I focused on a group of indigenous people, the Matsigenka, living inside Manu National Park.

One of these people is Alejo Machipango
[1], a hunter, farmer, and member of the water committee for the village of Yomibato. Alejo is about 32, but I would have guessed his age at 22. He is married and has several kids. He is a jokester. He likes chewing coca, drinking manioc beer. He takes his arrows with him most places, just in case. I saw him shoot at some birds, but never hit one. And he always laughs when he misses.
Alejo with his arrows, just in case.

One day, Alejo takes me to see the spring where Yomibato gets its water. The water system in the village was installed by a charity called Rainforest Flow between 2012 and 2015.

A few generations ago, the Matsigenka used to be more dispersed on the landscape. Each family lived apart, and households moved often. The whole community would gather together once a month, on the full moon, and have a big party with manioc beer. But many families decided to move to Yomibato to be near the school and clinic. As the community grew to several hundred, the local river and streams became contaminated with bacteria and waterborne illness became a chronic problem.

The slow sand filtration treatment tanks, with water committee members.

The newly-installed water system itself is a very simple slow sand filtration setup. Water is piped from a spring away from the main village to a series of three portable geomembrane tanks[2] filled with sand and rocks. Microbes living on the sand gobble up bacteria, viruses, Giardia, Cryptosporidium, and parasites. The water is stored in a 30,000 liter bladder tank that is essentially a big tough geomembrane pillow, then is distributed throughout the village through pipes. The whole system is gravity fed, so there are no pumps, no electricity required, no moving parts. It is also light and easy to transport by canoe. It was designed by hydrological engineer Humphrey Blackburn. The water committee clean the filters every couple of months and repair pipe breaks, and that’s about it.

We cross the river by canoe, stop to look at the filters and reservoir, and then start climbing the foothills of the Andes towards the spring. When we get there, the spring itself looks like nothing. A wet spot in the ground. A pipe with holes in it is buried below the surface, I am told.

We sit down to rest in the hollows made by the huge buttressed roots of massive fig trees. Alejo says he knows a tree nearby that is fruiting, and he and his friend Alex disappear, then reappear with their T-shirts filled with brown seed pods, about five inches long. They are called azucar huayo in Spanish; koveni in Matsigenka
[3]. The water committee hack them open with machetes and begin eating the sweet brown fluffy stuff inside. It is almost too sweet.

Alex with azucar huayo.

I ask Alejo about laying the 16 kilometers of pipe the project required. “Everybody came to work,” he says. “The women came. We all suffered a lot.”

I ask him if it was worth it. Sometimes, I think, development projects are more about what rich people think a community ought to want, rather than what they actually do want. “If we had to do it again, we would.” Alejo says. “One of my children died of diarrhea, and I had it many times.”

He says this so matter of factly that I don’t say the kinds of things I would say if someone back home told me their child had died. I suppose that in a place where people have a dozen kids and where childhood mortality is relatively common, it is possible that the etiquette is a bit different. But in truth, I am stunned that this happy-go-lucky guy who looks like a teenager has lost a child. And as a mother, I feel that vaguely sick feeling you get whenever you hear about any child dying.

I wonder if he is on the water committee because his child died, or if he just thought he’d make a little money without having to leave the village—which is the way most people make money in Yomibato, if they need some for soap or cooking pots or gasoline. But I don’t know how to ask him any more about this dead child.

Nancy Santullo, founder and director of Rainforest Flow.

The American woman who runs Rainforest Flow, Nancy Santullo, sees clean water as a basic step on the road towards empowering indigenous communities that have historically been victimized by outsiders: paid less than non-natives for their work, denied benefits owed to them as citizens, abused by those sent to help them

She is on a spiritual quest to make the Matisgenka strong and confident. Alejo already seems strong and confident, but I don’t know. His smiles may cover a shell thicker than the koveni

We walk back along the pipe, and it is a hot day, like every day. When we get to the first house of the village, I stop and take a long cool drink from the tap.

Access to clean, safe water has transformed health and sanitary conditions in the project communities, benefiting children especially.

Find out about Rainforest Flow's water projects in indigenous communities of the Peruvian Amazon at

Read more about the Matsigenka people and Manu Park in the June 2016 issue of National Geographic:

by Emma Marris
photography by Charlie Hamilton James

by Susan Goldberg
photography by Glenn Shepard


1.  As a young boy, Alejo appeared in the Discovery channel documentaries Spirits of the Rainforest (winner of two Emmys) and The Spirit Hunters, both filmed in Yomibato in 1992. Alejo's grandfather, Mariano Vicente, a storyteller, shaman, and "star" of the films, passed away in 2012. The Spirit Hunters , narrated by James Earl Jones, streams free online at Culture Unplugged.
2.  Slow sand filtration is a centuries-old technology used by many small towns as well as by the U.S. military on extended combat missions and the U.N. in disaster relief efforts. Read more at
3.  Azucar huayo (or jatobá in Brazil) is a legume seed pod from the tree Hymenaea courbaril L.



  1. Glenn, fantastic piece & great to see Charlie's article.. My aplogies for radio silence. I hope we can connect soon.

    1. Thanks for the kind words, but may I ask: who is this?

  2. Great stories and photographies.

  3. AnonymousMay 13, 2016

    great article, thanks for posting it
    Kevin Jernigan

    1. Ah, Kevin, thanks for the kind words again.

  4. AnonymousMay 14, 2016

    Excellent template for Matsigenka village design and functionality by Rainforest Flow.

    Maybe Brazil’s FUNAI could carbon copy a village for the “Tsapanawas” or “Sapanahuas”, who were filmed in June 2014 turning up at a village in Brazil’s Amazon near the border with Peru. They’re building something now. Not more than 10 months out of isolation.

    Likewise, Peru’s FENAMAD who are contacting a Mashco-Piro clan should do a feasibility study for village build, should the Mashcos indicate a desire to assimilate.

    I see Rainforest Flow acting as 3rd party consultant so Village design gets done right.

    1. Thank you for that encouragement and timely suggestion. Now that the slow sand filtration systems have been tried, tested and adapted in three communities over a period of 10 years, and all the technical kinks as well as social challenges worked out, it would be an excellent time for this project to scale up and bring these benefits to more communities in similar situations.

      An attempt to bring this technology to communities affected by the Camisea gas pipeline was met only with obstacles: my guess is that corrupt deals were made to benefit other, more profit-minded contractors (see But more recently we have been in touch with the Peruvian Culture Ministry about using indemnization funds from the gas project to install this kind of system in the Kogapakori-Nahua reserve adjacent to Manu Park.

      Than you for this suggestion and please send the Rainforest Flow contact information along to any institutions you know who might be interested in learning more about the technical as well as crucial social elements that made this project one of those rare successes in the often disappointing realm of community development schemes.

    2. AnonymousMay 15, 2016

      Cold call suggestion…Ya never know until you knock on the door.

      Tech Billionaire Philanthropist comes to mind. CEO Jeff Bezos of Amazon dot com.

      OVERVIEW: Bezos is relatively quiet as a philanthropist, although the Bezos Family Foundation, run by his parents, is very active.

      The Bezos Family Foundation was founded in 2003 and is run by Jeff Bezos's parents, and though Jeff's name doesn't appear anywhere on foundation documents, it is nearly fully funded with Amazon stock.

      ARTS & CULTURE: Bezos has given $10 million to the Museum of History & Industry (MOHAI) to establish a Center for Innovation at its new location. He has also put $42 million towards the prototype of a project referred to as the Clock of the Long Now, a clock meant to keep time for 10,000 years.

    3. Thanks for that suggestion, yes, the project has now been thoroughly field tested in three communities, and its time to scale up. We are pursuing some funding options through the Peruvian Culture Ministry, and Macarthur has also announced an interesting initiative as well. I'll look into it! As a fellow Princeton graduate, who knows, maybe he'll heed the call. Thanks again, and sorry for the much delayed response: I was on extended health leave and am still trying to catch up on backlog. Thanks again for the useful suggestion, Glenn

  5. excellent post on a timely issue. thank you.

  6. Thanks for your kind words Anna Luisa! Glenn