Desalination is less environmentally harmful than no desalination.
BSME | MPA | Assoc. DBIA | 💧 Water Resource Specialist, Market Strategies, Water Infrastructure Development
Critics of desalination often make the claim that desal is harmful to fish and the aquatic systems they depend on to survive. My argument is that if you want to protect fish, you might be better off with desal than without it. And the reason for this is base flows. These are flows that migrate from underground and feed rivers, streams, and other surface-water sources. This rarely comes up in conversations critical of desal, but surface-water base flows are essential to aquatic life. Yet they’re being threatened by the over-pumping of underground aquifers. Aquifers are being over-pumped because we need more water, and because large portions of the country have become permanently arid. With less runoff in these areas, aquifers are the only place we can get more water without the use of systems like — you guessed it — desalination. Because of aridification of the west, base flows need to account for a larger percentage of the flow of the river. Without these base flows, rivers and streams may dry up. And with them would go the habitats, vegetation and wetland ecosystems that keep freshwater fish alive. Base flows also help dilute pollution. And because they bring cool groundwater to the surface, they regulate water temperatures and provide pockets of cold water for fish to survive in higher temperatures. By turning to seawater desalination in lieu of groundwater, we’re able to leave more water in the ground to supplement the surface water supply. Maybe if more people realized this, they would recognize desal’s environmental benefits instead of shunning it based on misinformation.