The severe drought gripping Catalonia has triggered strict water restrictions and sparked heated debates about how this essential resource should be managed. Scientists warn that the current consumption model is unsustainable and urge a reformulation of water use strategies to secure long term resilience for the population.
The rising demand for water coupled with shrinking supplies worsens food and resource insecurity in many regions. Traditional approaches that rely on rainfall in arid zones and runoff from rivers are no longer sufficient to meet human needs.
Unconventional sources such as desalination can help close the gap between supply and demand. Yet desalination produces large volumes of concentrated brine discharged into the sea, a costly process with environmental and disposal challenges that merit careful management.
A 2019 study by researchers from Canada, the Netherlands and South Korea found that at that time there were nearly sixteen thousand desalination plants in operation worldwide, with about eight hundred in Spain, producing around one hundred forty million cubic meters of desalinated water daily. Approximately half of this output came from the Middle East and North Africa region.
Writers emphasize that reducing the environmental footprint of saltwater handling and cutting the overall disposal costs remain essential aims for best practice in desalination.
Serious impact on marine flora
Ecologists question the most common water purification model yet do not reject desalination outright. They acknowledge that in some scenarios desalination is necessary as a last resort, but call for it to be powered by renewable energy because of the high energy demands involved.
They argue for alternatives that emphasize water conservation and resource rationalization as Greenpeace has long advocated for. The return of untreated brine to the sea with high salinity can severely affect aquatic vegetation, especially the endangered Posidonia oceanica, a vital species that stabilizes beaches and maintains marine balance.
CREAF and other research centers warn about the energy intensity of desalination and the broader infrastructure costs of distributing desalinated water to where it is needed. They note that modern systems have become more efficient but still consume substantial energy per cubic meter of water.
The region currently relies on two desalination facilities that feed local networks, while other plants supply varying volumes to different river basins. CREAF notes expansions planned in the next five years that would increase overall capacity but come with large investment and ongoing maintenance needs.
High energy consumption
Beyond the economic cost, desalination carries a notable environmental price due to energy use and emissions. While energy efficiency has improved since the early days of desalination, the process remains energy intensive. In addition, building and maintaining the necessary infrastructure to transport desalinated water to demand centers adds to the environmental footprint.
Modern discussions also emphasize the environmental management of the desalination infrastructure itself, including the lifecycle of facilities and the long term maintenance of transport networks. Average energy use per cubic meter remains a key benchmark in evaluating overall sustainability.
Objections to purified water
Desalination and water purification are often useful for addressing urgent shortages but may not be a sustainable long term solution. The high costs and environmental impact of treatment and disposal drive calls for alternative approaches to meet water needs for industry, agriculture and households.
When water treatment is not reused, effluent returns to rivers and can affect river ecosystems. If reuse becomes the standard rather than discharge back into rivers, river flows may decline and ecological balance can be disrupted. This is a central concern voiced by environmental researchers.
Desalination and water reuse are seen as short term tools to manage droughts but are not considered sustainable in the long run due to economic, energy and environmental costs. The most prudent path is to curb demand and rethink the socioeconomic model that drives overuse of water resources.
Nature is the solution
The recommended course centers on maintaining natural hydrological cycles and prioritizing the health of water bodies and ecosystems. CREAF outlines eight practical steps to reduce consumption while preserving ecological balance.
1. Protect and restore natural water sources, rivers and aquifers.
2. Dedicate resources to decontaminating aquifers.
3. Avoid filling streams or drainage gaps with cement.
4. Refrain from channeling rivers and altering channels.
5. Halt illegal wells that extract water beyond permissible use.
6. Reduce widespread aquifer overuse.
7. Preserve stream environments and riverbeds.
8. Rethink the strategy of building further dams or locks that alter river flows and cause ecological disruption.
Business perspective
Industry groups argue that there is no single regulatory framework in Spain that strictly caps desalination plant discharges or the chemical properties involved. They stress the obligation to undergo environmental assessment for large scale new or expanded facilities and to meet defined environmental protection standards.
Communities have called for comprehensive environmental monitoring programs to safeguard sensitive areas from the salinity fluctuations caused by saltwater discharges, with a clear focus on protecting oceanic ecosystems such as seagrass meadows. Effective preconstruction and ongoing monitoring are cited as essential to limit local salinity spikes and avoid harming marine life.
In summary, desalination and water regeneration are important short term tools to address droughts, but they come with economic, energy and environmental costs. The recommended path emphasizes reducing water demand and aligning consumption with natural limits.
The overarching message is to align water policy with ecological health and to rethink the way water is used across agriculture, industry and urban life. This approach seeks to balance human needs with the integrity of natural systems for a sustainable future.