Lima: Desert city in need of water

…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.

Thousands of years ago great, pre-Inca civilizations lived in the Atacama Desert. Almost always the people lived along the rivers, where a constant supply of water resulted in ribbons of green through the otherwise bleak landscape. The lush riparian vegetation attracted wildlife, provided food for domestic animals and river water allowed crops to be grown year- round. There were droughts then, too, but the total population was less than 5 percent of what it is today. What was an inconvenience 2,000 years ago is potentially catastrophic today with so many people dependent upon a finite supply of water.

Desert Sun