Amid climate change, Peru revives pre-Columbian irrigation system
By Paula Bayarte
Lima, Apr 29 (EFE).- More than six centuries after the inhabitants of the Huarochiri Mountains built a system of communally managed irrigation channels to sustain agriculture, contemporary Peruvians are restoring the apparatus to cope with water shortages connected with climate change.
Known in the indigenous Quechua language as amuna (“to retain”), the idea goes back to the Huari culture, which flourished in the first millennium A.D. and left a legacy of practical knowledge that was absorbed by the Incas.
“Before we had rain from January to April, but in these last few years we have very little due to the climate issue. We have tried to restore these amunas to capture the water of the rains and filter it to benefit us and our agriculture and ranching,” San Pedro de Casta resident Beatriz Olivares told Efe.
Perched at an altitude of more than 3,000 m (9,836 ft) in the heart of the Huarochiri range, east of Lima, the village is surrounded by amunas that at first glance look like interlocking narrow paths through the underbrush.
Over the centuries since the Spanish conquest, most of the amuna networks have fallen into disuse.
In 2016, Aquafondo, a non-profit organization established to ensure an adequate water supply for Greater Lima, joined with the San Pedro de Casta community in a project to revive the irrigation system.
“The ancestors built the amunas. They did very valuable work, using the resources of the place: stones and clay, nothing more,” says Gregorio Rios, a resident involved in the initiative.
He notes with regret that many of his neighbors are unaware of the existence of the hundreds of kilometers of amunas, let alone their importance.
One of the amunas runs from a spring on the Carhuayumac River down the mountain, supplying cattle ranches and alfalfa fields near the top and fruit orchards lower in the valley.
“We began this work five years ago and we have recovered 18 km (11 mi) of amunas, which represents more than 4 million cubic meters of water a year,” Aquafondo executive director Mariella Sanchez told Efe.
When authorities proposed installing a new irrigation system, it was the residents of San Pedro de Casta who suggested restoring the amuna network instead.
And while 80 percent of the water collected is used in the community, the remainder “indirectly reaches the city of Lima,” Sanchez said. EFE pbc/dr