Lima, Peru, is the second-largest desert city after Cairo, and it shows. Climate change has ravaged the glaciers that feed the city’s water supply, and the region’s brutal wet/dry cycle means water supplies in Lima are intermittent at best. Now that’s slated to change. The city’s water utility company will revive a set of pre-Inca waterways that could keep faucets running.
New Scientist reports that the plan will breathe new life into 1,500-year-old structures called amunas, which were built by the Wari people (who predate the Inca by centuries). It turns out the Wari were great urban planners, building a complex water conservation system that captured mountain water during the rainy season via year-round springs, pools and canals.
A Lima-based researcher explains to Environment & Energy News that the structures capture rainwater and funnel it across the mountainside instead of letting it flow downhill. The water infiltrates the ground and resurfaces during the dry season, when it’s most needed. Now, Lima’s water utility wants to re-grout the canal portion of the amunas so they do the job they were given 1,500 years ago.
“The idea is to build a timelag into the hydrological system, delaying water run-off for weeks or even months until it benefits water supply in the dry season,” hydrologist Bert De Bièvre tells New Scientist. And at $23 million, the proposed project will be much cheaper than other proposed solutions, like desalination plants. Officials hope it could raise Lima’s water supplies by as much as 60 percent during the dry season.
And Peru isn’t the only country turning to ancient water technologies as it tries to deal with a dry climate. An Indian man recently won what has been dubbed “the Nobel Prize for water” after bringing traditional rainwater reservoirs called johad to more than 1,000 villages in India.