LIFE Project: Demonstration of a cost-effective solution to prevent evaporation losses, ensure water quality, and produce renewable energy in agricultural water reservoirs

The European Environment Agency estimates that around 30% of EU citizens and 20% of European territory are affected by water stress on average each year. Agriculture accounts for around 22.5% of total freshwater withdrawals in the EU, with significant differences between Member States. In arid or semi-arid conditions (typical of the southern EU), irrigation accounts for almost 80% of agricultural water use. Agricultural water reservoirs (AWRs) play an important role in agricultural irrigation systems in Europe, especially in areas where water scarcity is a critical issue, such as southern Spain. However, AWRs are open to the atmosphere most of the time, resulting in significant losses. In the Segura basin alone, annual losses amount to 78 hm3, and evaporation affects between 6.5% and 11.7% of the water level.

However, existing solutions to minimize this loss are not cost-effective for agriculture. Furthermore, the sector's energy demand has increased due to the installation of more efficient irrigation systems. This has led to the installation of solar panels on drip irrigation systems to produce clean energy and balance costs. The panels also partially cover drip irrigation systems, helping to reduce evaporation without offering a cost-effective solution.

Furthermore, AWRs are vulnerable to excessive algal growth (eutrophication), which negatively affects water quality and can produce unpleasant odors. Algal growth can also block pumps, filters, and pipes, while its decomposition depletes oxygen levels in the water, further reducing water quality issues and releasing iron and nutrients from the sediments. There are a variety of methods for treating algal blooms, but their effectiveness varies widely and requires further research. A common solution is to cover the basins with windbreaks or floating covers on the water's surface.