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Reviving an ancient irrigation system in Bolivia

The modern camellon system is designed to cope with floods and drought (Mark Chilvers/Oxfam)
The modern camellon system is designed to cope with floods and drought
Mark Chilvers/Oxfam

In 2008 flooding affected one-quarter of the population in the district of Beni in the north east of Bolivia and caused more than US$200 million in damage. Beni is prone to alternate flooding and drought but this was the worst for more than 50 years. Dunia Rivero Mayaco is one of the farmers who lost everything: "I had planted rice, maize, bananas and onions on my plot of land. But the water left nothing. I lost my house too," she recalls.

But in the 1960s, archaeologists revealed an ancient agricultural system, developed by a pre-Inca civilisation, which not only coped with environmental challenges such as flooding and drought, but also improved soil fertility and productivity. Three thousand years later, this ancient irrigation system has been revived by the Kenneth Lee Foundation, with funding from Oxfam.

A sophisticated system

Elevated fields of up to two metres high, known as camellones, are constructed to be above the height of floodwaters, and are surrounded by water channels. The elevated fields are somewhat like the raised beds that some vegetable gardeners construct, though on a much larger scale. During the rainy season, the surrounding channels fill with floodwater, preventing the crops in the fields being washed away. The water can then be used to irrigate and provide nutrients to the camellones during periods of drought. "The ancient cultures in Beni did not try to fight against the flooding," explains Oscar Saavedra, executive director of the Kenneth Lee Foundation. "They saw it not as an obstacle but as an opportunity."

click to enlarge image (BBC News)
click to enlarge image
BBC News

The project is in its early stages, but initial results have been promising. "In the old system we lost a lot of plants and seeds when the floods came. Then we had to wait for the water to go down before we could start replanting," Yenny Noza, a local farmer, recollects. "But now, the plants don't get covered with water when the flood comes. So we can still harvest and then we can immediately sow seeds again." Maria Salas agrees: "These camellones will now help us when the floods come. Crops like bananas, that die easily if flooded, will survive better. And we can now plant fruits like lemons and oranges."

Reaping the rewards

"The first trial camellones, built in 2007, were the only structures that survived the 2008 floods, which proved the system could help communities adapt and strengthen their livelihoods," explained Roger Quiroga, Oxfam's disaster risk reduction and adaptation coordinator in Bolivia. By July 2009, 400 families in five communities surrounding the district capital, Trinidad, were involved growing mainly cassava, maize and rice. "I didn't want to lose everything again," Mayaco reflects. "That's why I am working here on the camellones."

Improved fertility has the potential to reduce deforestation (Mark Chilvers/Oxfam)
Improved fertility has the potential to reduce deforestation
Mark Chilvers/Oxfam

Due to the poor soil conditions, slash-and-burn agriculture is widely practised in Beni, causing extensive deforestation. But, according to the Kenneth Lee Foundation, improved fertility of the camellones means that farmers are able to produce up to three crops a year and much higher yields than can be achieved by conventional practices in the region. In Beni, for example, a traditional farmer can expect to harvest about 15 tonnes of cassava per hectare, but camellon farmers have achieved yields of up to 100 tonnes per hectare per year. Not only does this improve the food security of families, but it has the potential to reduce deforestation.

The water channels are vital to the success of this system, providing irrigation and year-round nutrients. Fast-growing aquatic plants called tarope purify the water, encouraging fish to colonise the canals, and these in turn provide an additional source of food and income. The tarope also improves soil fertility. "When you spread tarope on the soil, it preserves the humidity of the earth and gives it more nutrients," Oscar Peñaranda, a local farmer reveals. "Tarope is a fabulous plant for fertiliser."

A vision for the future

After seeing the results for themselves, farmers like Rafael are convinced that the system works (Jane Beesley/Oxfam)
After seeing the results for themselves, farmers like Rafael are convinced that the system works
Jane Beesley/Oxfam

Overcoming scepticism about the camellon system was the biggest challenge the project faced. "A climate of distrust was generated when we asked the participants to implement a technique that not even the agricultural engineers knew how to execute," Quiroga remembers. But, after seeing the results for themselves, the communities are convinced. "We thought it wouldn't work because we know that the soil is very poor - it's dead here and not good for agriculture," Rafael Crespo Ortiz explains. "But with this technology we have learnt what can be done."

Despite these challenges the camellon system is already being used in Colombia, Ecuador and Brazil. "The learning gained from the camellones project in Bolivia will have major ramifications for other disaster-prone areas," Quiroga believes. Saavedra agrees: "This process could be repeated in various parts of the world with similar characteristics, like Bangladesh, India and China."

Date published: November 2009

 

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