Population growth combined with climate change impacts have pushed many countries to invest in desalination technologies as a way to increase water supply and, in some cases, to improve water quality. Water managers have often considered this “hard-path” approach as a “panacea” that can solve many problems. However, research has shown that desalination may have negative impacts for both social and ecological systems. The purpose of this project is to examine the mechanisms used by existing desalination plants to alleviate the negative impacts of this technology in both social and ecological systems.
Methods include the analysis of three case studies: (i) Carlsbad Desalination Plant, in California, United States; (ii) Los Cabos Desalination Plant, in Baja California Sur, Mexico; and (iii) Hadera Desalination Plant, in Haifa District, Israel. These three plants were selected because they utilize the same desalination process, represent different scales, are currently active, and experience different political and socio-economic contexts.
Results. Although all plants use the same technology - reverse osmosis - we found that Hadera and Carlsbad have made important engineering variations to decrease the negative impacts on marine ecosystems. In addition, we found that water users in Hadera and Carlsbad accept desalinated water for every use, but it is combined with other water sources. In Los Cabos, however, desalinated water is the main water source and people still buy bottled water for drinking. Furthermore, the three plants use energy from fossil fuels, but Carlsbad has significantly improved energy efficiency, and therefore, decreased their carbon emissions. Finally, having planned the introduction of desalination in Israel for more than a decade, and having exhausted all the available soft-path approaches, the integration of desalination into their overall water management has been smooth and effective. Likewise, the opening of the Carlsbad plant was combined with other soft-path approaches that allowed desalination fit easily into their whole water management, and not be a “bandage” solution to urgent problems. Los Cabos, on the other hand, has no clear environmental assessment, and is heavily subsidized, which threatens the sustainability of the plant. In addition, the opening of Los Cabos plant has promoted population growth and incentivized the tourism industry, exacerbating the problem in the long-term. We conclude that planning for desalination by having exhausted soft-path approaches prior to adopting this technology is critical for the sustainability of water resources.