On a tiny island off the coast of California, water is getting both more scarce and more expensive. Santa Catalina Island used to rely on groundwater and their main reservoir to meet their water needs. However, times have changed. With the 4,000 full-time residents and 1 million visitors a year, water is used up much too quickly. Really, they should have run out of water a year ago. Only a desalination plant running 24/7- mixed with serious water restrictions and rations- is keeping Catalina afloat. The desal plant has taken a bit of the pressure off the citizens of Catalina Island, but it is still very controversial. What are some of the pros and cons of desal plants? And which one outweighs the other? First of all, an obvious pro is that it is a drought-immune solution; no matter how little freshwater we have, the oceans are still there. Next, it is convenient as Catalina Island is an island; it’s surrounded by salt water on all sides. Finally, Catalina is small enough where the brine (leftover salt) that is being disposed of is not substantial enough to seriously harm any wildlife or ecosystems in comparison to the huge, large-scale plants proposed by some recently. To give you an idea, the Avalon plant (in Catalina) produces 240,000 gallons of drinking water a day versus a large-scale plant that was vetoed would have produced 50 million gallons a day. However, cons include the fact that desal plants are very expensive to build and require a lot of energy to run effectively, which is also very expensive. The energy used to run desal plants usually comes from fossil fuels, but one innovative plant in California used solar panels. Finally, the amount of saltwater that goes into the plant is drastically larger than the amount of freshwater that comes out; it takes 2 gallons of seawater to make 1 gallon of freshwater. Overall, there are many important pros and cons to desalination plants, but which will outweigh the other in a time of serious drought?
Sources:
vittana.org/13-important-desalination-plants-pros-and-cons
Energy for the Environment 
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