Lima: Desert city in need of water

James Cornett in the Desert Sun (Palm Springs, California): With 8 million inhabitants Lima, Peru is an enormous city. That it is located near the heart of the Atacama Desert, one of the driest places on earth, seems shocking. “Where does the city get its water?” was the first question I asked the taxi driver who picked us up at the airport. “From the rivers, when they are running,” he said.

The Atacama Desert is a long, arid zone that hugs the west coast of South America. To the west is the Pacific Ocean and to the east are the Andes, one of our planet's great mountain ranges. Snow and rain fall in the Andes for several months each year. Most of the runoff heads into the Amazon Basin but much of it flows west towards the Pacific Ocean. Before it reaches the Pacific it must run through the Atacama Desert. Lima obtains nearly all of its water from this runoff, via several rivers that run from the Andes to the Pacific.

In the past the flow of the rivers was adequate to supply Lima's needs. But Lima is a growing city and the flow of water down the rivers has decreased during the Andes' dry season. In the past glacial melt kept river levels high in the dry season but the glaciers are disappearing due to global warming.

Now Lima has a water shortage for many months of the year and recent droughts are exacerbating the problem even further. Shutting off the water supply to homes and businesses during the wee hours of the morning is occasionally done and cutting back on landscape watering is also practiced. These water-saving strategies, however, appear to be insufficient to resolve Lima's long-term water problem. Desalinization of ocean waters is too expensive for Peru and would require the use of the planet's ever-dwindling supply of fossil fuel. Stay tuned….

Slums on the slopes of San Cristobal in Lima, Peru, shot by James Preston, Wikimedia Commons via Flickr, under Creative Commons Attribution 2.0 License