Peru harnesses ancient canal system to tackle Lima water shortage
Photograph: Courtesy Gena Gammie
n the mountains above the Peruvian capital Lima, the world’s second largest desert city, scientists are working with farmers to restore ancient canals, believed to predate the Inca empire, in an effort to tackle the city’s increasing water shortage.
The system – known locally as mamanteo, a term derived from the Spanish word for suckling, or amunas – could help the city of nearly 10 million inhabitants to ride the seasonal extremes of floods and droughts.
It works by funnelling water from highland streams into the mountain itself, where it percolates through cracks and natural aquifers over months to emerge in springs and natural reservoirs.
“It’s all about building in delays in the hydrological runoff of these catchments because if the water continues through this stream it will reach the village downstream in a question of hours. Letting it seep through the mountain, we expect to build in delays of weeks and hopefully months,” says Bert De Bièvre, an expert on Andean water basins working with the Consortium for the Sustainable Development of the Andean Ecorregion, an NGO.
The delay means that the abundant wet-season moisture in these highlands at more than 3,500 metres above sea level can be gradually distributed during the dry season, which can last more than half the year.