The ancient pre-Inca civilization of the Wari is a marvel to archaeologists because it grew out of one of the driest regions in the world.
Their technology for water was so good that the modern city of Lima, Peru, is now turning to its crumbling infrastructure to help solve the water crisis for 9 million people. Today, the city is the second largest desert city after Cairo, Egypt.
As reported by the New Scientist, the city’s water company, Sedapal, is looking to grout the ancient canals that carry runoff from the Andes as a cheaper alternative to building an expensive new desalination plant. The stone canals, called amunas, capture water from high on the mountains and carry it further to the base, where they feed year-round springs that provide water to the region through the dry season.
Bert De Bievre, who works with the Peruvian NGO behind the project, told New Scientist that the idea is to build a “time lag” into the hydrological system, so water is available during the dry season. The cost to repair the canals is supposed to be $23 million–a small sum considering it could reduce the city’s current dry season water deficit by up to 60%.
Forest Trends, a U.S. group helping to support the project, says that the water utility is also undertaking other “green infrastructure” projects to address growing water needs, such as restoring natural wetlands so they retain more water in the wet season and helping farmers better manage their livestock. The utility plans to charge a 5% user fee to fund the work.
Lima’s water stress situation isn’t unique, especially as climate change stresses places that are already dry. California is imposing drastic water reductions and Sao Paulo, Brazil, is also contemplating drastic measures. Unfortunately, unlike Lima, few cities have the similar advantage of leaning on the wise building methods of civilizations that existed more than 1,000 years ago.