This widespread failure to implement the Water Framework Directive has led to 64% of large dams' reservoirs not meeting ecological flow standards, which are vital for sustaining aquatic ecosystems.

Zero's analysis of 121 water bodies revealed that 78 reservoirs are non-compliant, with 50 lacking defined ecological flows and 28 having flows but no water releases, contributing to ecological degradation.

This decline is further exacerbated by legal non-compliance and water shortages caused by insufficient ecological flows, which impair river ecosystems and threaten biodiversity.

The absence of ecological flows impairs rivers' self-purification capacity and water quality, with only 7.4% of reservoirs equipped with fish transposition devices, worsening ecological fragmentation.

The report emphasizes that the low percentage of reservoirs with fish translocation devices and the lack of ecological flows collectively undermine river health and ecosystem resilience.

On September 30, 2025, the environmental organization Zero filed a complaint with the European Commission, accusing Portugal of serious non-compliance with water management laws, particularly regarding ecological flow standards.

The lack of adequate ecological flows and river fragmentation are linked to a 30% decline in the European water shrew (Galemys pyrenaicus) over the past decade, highlighting the environmental impact of poor water management.

Zero calls for a moratorium on new dam constructions to reassess water management strategies, criticizing current policies that prioritize intensive agriculture, which consumes over 70% of Portugal's water resources.

The organization urges the government to halt new dam projects like the Pisão dam, arguing that such developments conflict with legal goals to restore rivers to good ecological status by 2027 and comply with the Nature Restoration Law.

While the UN observes World Water Day on March 22, Portugal has celebrated its National Water Day on October 1 since 1983, marking the start of the hydrological year when water reserves are at their lowest, emphasizing the importance of water resource management.

Zero condemns government funding of controversial projects like the Pisão dam and criticizes the diversion of public funds to such initiatives, which conflict with legal objectives to restore river ecosystems by 2027 and adhere to the Nature Restoration Law.