This article offers an in-depth analysis of the legal principles governing the delimitation of streams in Greece, situating the discussion within the broader context of climate change, the
European Green Deal, and the evolving demands of national environmental law. The authors
highlight that, as climate-related risks intensify, adapting Greek legislation to better protect
human life and natural ecosystems becomes increasingly imperative.
A central focus of the study is the legal treatment of streams as protected natural ecosystems,
both under EU law and Greek constitutional and statutory provisions. Stream delimitation is
presented as a critical legal and technical process, essential for preventing harmful interventions and ensuring that any work near watercourses are planned on the basis of environmental impact assessments and sound hydrological data.
The article systematically sets out the key principles of environmental protection that guide stream delimitation and are consistently affirmed in the case law of the Council of State (ΣτΕ),
including:
- Conservation of the Natural State of Streams – Streams must be preserved in their natural form, with boundaries and flood lines determined on the basis of geomorphology, historical flow patterns, and environmental data.
- Recognition as natural ecosystems – Streams possess unique ecological functions and microclimates; any alteration of their character or use is constitutionally prohibited.
- Protection of unimpeded natural function – Construction projects are permissible only when they safeguard the free flow and ecological integrity of the stream; only essential technical works are allowed.
- Prohibition of changing their primary purpose – The role of streams in water runoff and ecological balance cannot be altered through administrative actions or development.
- Principle of Sustainable Development – Stream delimitation must integrate long-term environmental protection with responsible planning, ensuring intergenerational equity.
Special attention is given to the non-fragmentary delimitation requirement, drawing on landmark ΣτΕ decisions such as the Podoniftis, Oleander Stream, and Great Stream of Rafina cases. These judgments affirm that delimitation is a mandatory precondition for zoning actions and environmental permitting. Where delimitation has not yet occurred, projects may proceed only if it is demonstrably ensured that they will not impair the stream’s natural function.
The article also explores the precautionary principle under EU law, stressing that authorities
must act proactively—even in the presence of scientific uncertainty—when a project may pose risks to a stream’s ecosystem.
Finally, the authors analyse the necessity of examining alternatives within Environmental Impact Assessments, reaffirming that judicial review focuses on the legality, completeness, and adequacy of the environmental evaluation supporting administrative decisions.
In conclusion, the article underscores the need for a holistic and scientifically grounded approach to stream delimitation—one that reconciles environmental protection with urban
planning demands. It highlights that safeguarding watercourses requires a rigorous legal framework, effective enforcement, and alignment with constitutional principles and EU environmental law, ensuring the ecological integrity of streams while enabling orderly and sustainable development.