Could desalination be the solution to water shortages?
Well, it’s complicated. But first, what is desalination? Desalination is the transforming of saline water into fresh water. There are two methods: thermal desalination and reverse osmosis. Thermal desalination relies on heating up saline water and capturing the condensed steam, while reverse osmosis utilizes high-pressure pumping to push saline water through semi-permeable membranes that filter out the salt (USGS).
Desalination plants are commonly found in the Middle East and in certain regions of the United States, such as along the coasts of California, Florida, and Texas (The New York Times). 300 million people around the world receive water from desalination plants (Yale E360), and more than 60 percent of Israel’s drinking water is sourced from desalinated sea water (The New York Times). In the United States, the Carlsbad Desalination Plant serves 3.1 million people in the San Diego metro area. But, while desalination plants do exist, there are a few drawbacks to implementing desalination at a larger scale (USGS).
Let’s take the proposed pipeline that would divert water from a desalination plant in Puerto Peñasco, Mexico to Phoenix, Arizona as an example. Since 2000, Phoenix’s population has grown by almost 50 percent, and despite the city struggling to meet water demands, development has not halted. Desalination would benefit residents of Puerto Peñasco who have faced water shortages, and the pipeline would provide Phoenix with water to meet the demands of its growing population. However, desalination is energy intensive and extremely expensive—the desalinated water would cost ten times what water from the Colorado River costs. Additionally, only half of the water used in desalination is potable, and the other half is brine water twice as salty as the ocean. Brine water has to be dispersed properly in the ocean, but, in the case of the Puerto Peñasco desalination plant, the brine water would be dumped in the shallow part of the Gulf of California, threatening marine ecosystems and fisheries. Additionally, the proposed pipeline would cut through the Organ Pipe Cactus National Monument, an ecologically sensitive area and UNESCO Biosphere Reserve that is significant to the Tohono O’odham Nation (The New York Times).
So, desalination may be a legitimate source of drinking water in certain areas of the world, but there are many drawbacks to consider. Many environmentalists argue that there are other conservation techniques that should be implemented first to address water shortages. This includes toilet-to-tap recycling, stormwater runoff treatment, and cutting down on development in cities like Phoenix (The New York Times; Yale E360).