Rafina’s Great River

The last free waterway of Greece’s Attica region

Rafina's Great River



Mesogeia plane, East Attica


  • Boundaries

Mount Pentelicus (N-NE), Hymettus mountain range (W-SW), Hills (S)

  • Area

150 sq. km

  • Average slope
  • Max Altitude

920 m


Paianias, Pallinis, Rafinas-Pikermiou, Spaton-Artemidas


25 km


W - E


South of Rafina's port

Main tributaries

Panagitsa str., Pallini str., Spata str., Valanaris, Ag. Paraskevi str.

Smaller streams

Geraka str., Leontariou str., Argithea str., Bakalopoulou str.,

Sambani str., Lykorema str., Palios Milos str., Daou Pentelis str.,

Kallitechnoupoli str., Ag. Barbara str.

The unique value of the Great River of Rafina lies in the fact that it is one of the few rivers of Attica that remains natural for the longest part of its length. Its catchment area can be seen in the adjacent image as well as in the  digital interactive map.

Due to its high ecological importance, the waterway as a whole has been characterized by presidential decree as “preservable stream of environmental interest” (Government Gazette 281/D’/1993) and “Water Stream of Priority A'” in accordance with the provisions of article 20 par.4 of Law 4277/2014.  It is subject to specific regulations based on the Mesogeia Urban Control Zone regulation (Government Gazette 199/D’/2003). The Estuary of the Great River is a protected priority A’ wetland (article 54 of Law 4559/2018). It is an important ecosystem with rich biodiversity.

Digital Elevation Model map of the Great River drainage network and catchment. (Karymbalis et al. 2021)

The Valanari stream is also of particular importance, not only because of the extent of its catchment area (33 sq. km) – the largest sub-basin of the Great River basin – but also because of the special value and uniqueness of the paleontological findings (“Pikermian fauna”).

Rafina's Great River


The catchment area of Rafina’s Great River includes 150 square kilometers (only about 20% thereof in urban areas). Based on the monitoring application of the Water Framework Directive (Directive 2000/60) the basin is divided into three water bodies: the Lower Part of the Great River, the Valanaris Stream and the Upper Part of the Great River. Water bodies are distinct river segments. The dominant and characteristic natural types of habitats, which have been identified in the water bodies of Rafina’s Great River basin, are the following:

Lower part of the Great River (ΕL0626R000100010N):

  • Intermittent Mediterranean rivers from Paspalo-Agrostidion (3290)
  • Estuaries (1130)
  • Reedbeds with Phragmites/Typha (72A0)
  • Platanus orientalis forests (92C0)
  • Southern riparian forests-stems and heaths (Nerio-Tamaricetea)(92D0)

Valanaris (ΕL0626R000100011N):

  • Intermittent Mediterranean rivers from Paspalo-Agrostidion (3290)
  • Reedbeds with Phragmites/Typha (72A0)
  • Platanus orientalis forests (92C0)
  • Southern riparian forests-groves and groves (Nerio-Tamaricetea) (92D0)

Upper Part of the Great River (ΕL0626R000100012N):

  • Intermittent Mediterranean rivers from Paspalo-Agrostidion (3290)
  • Gallery forests with Salix alba and Populus alba (92A0)
  • Mediterranean sea bream (Juncetalia maritimi) (1410)
  • Reed beds with Phragmites/Typha (72A0).

In several places there are impressive stands of riparian vegetation and riparian forests. Riparian stands next to continuously flowing rivers are particularly rare formations in Attica. Of particular interest are the habitats “Forests with Salix alba and Populus alba (92A0)” on the Upper Part of the Great River in the Petreza area where there are stands of Salix alba (Salix alba) of a relatively young age together with isolated specimens of silver poplar (Populus alba). Similarly, in the area of this branch there are extensive riparian wetlands of high interest for biodiversity (especially because these formations are rare in Attica).

Data from the report of HCMR, 2019.

Due to its great and strategic ecological importance, Rafina’s Great River has been characterized in its entirety as a 1st Priority Waterway in accordance with the provisions of Article 20 par.4 of Law 4277/2014 and a River of Special Environmental Interest with the provision of a 50m wide zone on either side of the river axis, where special conservation arrangements and protection conditions apply regarding uses and functions. The Estuary of the Great Rafina River with code EL30501900 and an area of 59 hectares is a 1st Priority Wetland (Article 54 Law 4559/2018) and is included in the Register of Protected Areas of the River Basin Management Plans of Directive 2000/60/EC.

From August 2018, in accordance with article 54 of Law 4559/2018, in the Rafina’S Great River Estuary, building, landfilling, the exercise of disturbing activities and any activity that degrades the ecological situation are prohibited, as well as the issuing of building permits until its demarcation with the issuance of a Presidential Decree, which follows the provisions of the Biodiversity Law (L. 3937/2011) and not those for the demarcation of streams (L. 4258/2014). This ban was instituted so that the design and implementation of projects do not cause degradation and irreversible effects on the wetland ecosystem, such as the deforestation of vegetation with heavy machinery. The application of these provisions “constitutes a self-evident legal and moral principle that governs the modern European and national framework” [Greek Biotope/Wetland Centre 2023]. The fact that the 1st Priority Wetland at the Estuary of Rafina’s Great River has not yet been demarcated by presidential decree does not mean that it is not protected as such [1].

[1] Minutes of the processing of Presidential Decree 151/2022 for the wetland of Perea.

The floodplains of Rafina’s Great River in the plain of Spata, especially that of Petreza, and its wetlands, especially the 1st Priority Wetland of the Estuary, in their natural state are an important ecological part of the river system and provide many valuable ecosystem services: they filter and store water, they store carbon, they ensure both natural flood protection by slowing the flood flow downstream and the orderly functioning of river ecosystems and contribute to maintaining the high biodiversity that exists in these systems. The preservation of the natural functions of the river and its connection with its floodplain are necessary factors in order to achieve a satisfactory conservation status in the habitats or species that are highly dependent on the watercourses associated with them.

Petreza floodplain

The management project of Rafina’s Great River will have serious negative effects on water bodies. It will degrade natural habitat types and eliminate some, which have a very limited distribution in the area. In Petreza, some habitat types rare in Attica will disappear, such as “Forests with Salix alba and Populus alba (92A0)” and “Mediterranean grasslands (Juncetalia maritimi) (1410)”. Almost all riparian marshes or other wetland elements that currently exist in riparian zones will disappear. Because the survey of the fauna and flora has not been completed to a satisfactory extent, the total damage to the area’s biodiversity cannot be easily estimated. It is certain, however, that some species will disappear from the Great River watershed and there will be a complete degradation of natural formations whereas the ecosystems will not be able to recover to the degree of structure and function they are today. The project will also negatively affect the 1st Priority Wetland of the Estuary since the complete settlement of the entire estuary and the mouth of the stream is foreseen, with serious negative effects on many groups of aquatic fauna [HCMR 2019].

In a similar management project of the Erassinos river, the EIB Complaints Mechanism found that the environmental documentation (2017) for Erassinos did not emphasize 1st Priority protected wetlands and protected species by taking appropriate measures and by justifying those measures and did not quantify the project’s impact on them [EIB-CM 2023].

Rafina's Great River


In Rafina’s Great River, its wetlands and floodplains (Petreza), around 150 species of birds have been recorded [ΗCMR 2019]. The majority has been observed near the estuary due to the increased presence of observers there, but also due to the fact that the brackish ecosystem of the estuary attracts large numbers of migrating waders and herons. Of the species recorded, 23 are species of Annex I of Directive 2009/147/EC [Hellenic Ornithological Society 2019, 2023]. The vast majority of them are herons, gulls and waders. The remaining two (the Peregrine falcon and the Booted eagle) are predators seen during migration (Peregrine falcon) or in winter. Among the nesting species in the stream are the  common moorhen (Gallinula chloropus), the Cetti’s warbler  (Cettia cetti), the great reed warbler  (Acrocephalus arundinaceus), the eastern olivaceous warbler (Iduna pallida) and the  little ringed plover (Charadrius dubius). More generally, the avifauna remains remarkably diverse, mostly during the migration season.

The importance of the area goes beyond local or regional value because many endangered migratory species are regularly observed. According to recent analyzes of ornithological data, in combination with the small wetland of Artemida, the area of the Great River’s Estuary and Petreza (together with Loutro in the Plain of Spata) meets the inclusion criteria for the designation of an Important Bird Area (IBA) and Special Conservation Zone within the framework of the Natura 2000 network [HCMR 2019].

Any intervention [...] will cause significant and irreversible damage to the ecosystem of the Rafina Great River and in particular to the bird species that nest in this area. It is certain that the loss of the large (in height and age) Sycamores, Whites and Willows will be a serious blow to the bird populations. The projects will also have major impacts on the populations of amphibians, reptiles and freshwater fish that live in the waters of the Great River. This in turn will cause a loss of available food for birds feeding on the above organisms.

The approved projects […] will permanently and irreversibly change the physical form of the river, effectively turning it into a stormwater conduit. These projects completely ignore the wetland character of the river while they are now considered outdated and regressive, both at the European and international level, where the preservation of islands of natural environment and biodiversity in the urban fabric is a particularity.

Hellenic Ornithological Society, Reports 2019 & 2023

The European eel (Anguilla Anguilla) is a migratory species with a unique life cycle. The records of the  Hellenic Centre for Maritime Research (HCMR) show that in Rafina’s Great River a significant population of eels is maintained in several places downstream and through the river. Eels enter from the sea and usually survive for 8 to 12 years in fresh water before returning for the migratory breeding journey to the Sargasso Sea in the Northwest Atlantic from which they never return. These relatively long-lived fish require suitable conditions within inland waters (adequate cover, food, stable hydrological conditions and relatively good habitat condition or quality) to survive.

The European eel is a critically endangered species because it is steadily declining at an alarming rate worldwide, due in part to human activity.  EU Eel Regulation 1100/2007 obliges Member States with river basins that are habitats for the eel to adopt and implement measures to make the rivers accessible and to improve the eel’s river habitats.

Ευρωπαϊκό Χέλι (Anguilla Anguilla)

The Marathon minnow (Pelasgus marathonicus) is an endemic fish of Eastern Central Greece and Attica, with a very limited global distribution. It has been classified as Near Threatened in the red list of the International Union for the Conservation of Nature and Natural Resources (IUCN) and is listed as Endangered in the Red Book of Threatened Animals of Greece. One of the most important Marathon minnow populations in Attica is found in Rafina’s Great River (Upper stream) in suitable habitats with extensive reedbeds and river lakes. This population was discovered in 2018 by HCMR’s researchers. The population is particularly vulnerable to changes in the natural habitats of the riverbed and riparian zone (because the species is “limnophilous” and requires constant “quiet” waters with riparian marshes). In its Findings on the management project of the Erasinos river, the Complaints Mechanism of the European Investment Bank (EIB-CM) found that the information about the Marathon minnow, provided in the environmental documentation of the project, was incomplete and that the required special measures for management and monitoring had not been foreseen since the environmental impacts during the works may not be temporary due to their nature.

In the spring of 2018, HCMR collected individuals from a population of freshwater blenny  (Salaria fluviatilis) near the mouth of Rafina’s Great River. This is the only population of the species in Attica. This species is extremely vulnerable to changes in flow regime and river habitats. While the species has a wider distribution in rivers and lakes in the Mediterranean Basin, many populations have disappeared due to anthropogenic pressures and degradation.

According to HCMR (Report 2019), with the implementation of the management project in Rafina’s Great River, it is very likely that the Marathon minnow and the freshwater blenny  species will disappear and that there will be disastrous effects on the local population of the European eel, which will be felt far beyond the borders of Greece.

In the riparian zone as well as in the adjacent land areas, just next to the banks of the river, there is a relatively diverse herpetofauna, which survives here, within the urban fabric and because of the riparian zone of the Great River. The stream and the riparian zone act as ‘green corridors’ for the reptiles. Reptiles that regularly occur in the area include: Lizards such as the European copper skink (Ablepharus kitaibeli), land turtles such as the marginated tortoise  (Testudo marginata) and snakes such as the slender whip snake (Platyceps najadum). The  Balkan terrapin  (Mauremys rivulata) is also an important record for the Great River. While a complete inventory of all the reptiles of the area has not been made, the list of species may exceed 10 species. Many of these species are protected by Greek legislation.

Νεροχελώνα (Mauremys rivulata)

The area has significant populations of amphibians. Many thousands of Balkan Water Frogs (Pelophylax kurtmuelleri) and  European green toad (Bufotes viridis) breed and live in the waters and on the banks of the area. The area is also home to a small and isolated population of grass snake (Natrix natrix). Their presence is considered important at a local level because this species requires areas with water and is vulnerable to land use changes in dry-thermal Mediterranean landscapes. Water snakes in particular are at risk of disappearing from the management project of Rafina’s Great River.

Data from HCMR Report, 2023.

The Great River of Rafina, as one of the few remaining natural water systems of Eastern Attica, hosts a significant number of aquatic macroinvertebrates. Aquatic macroinvertebrates, and especially insects, are of great ecological importance since these organisms have a high potential as decomposers of dead organic matter, while at the same time they can be used as biological indicators of the state of aquatic ecosystems.

Thanks to the diversity of the habitats of the Great River, there are numerous species of dragonflies, such as Crocothemis erythraea, Calopteryx virgo, Sympetrum striolatum, Lestes macrostigma, Platycnemis pennipes, Anax imperator etc.

Ποταμοκάβουρας (Potamon fluviatile)

Also there are Trichoptera of the species Hydropsyche peristerica, and various species from the families Hydroptilidae and Glossosomatidae, while a significant number of Coleoptera are found in the sections of the river with enough vegetation and with moderate or stagnant flow (e.g. Scarodytes halensis). Various species of gastropods (aquatic snails) such as Physella acuta (Pneumophora) have also been collected. In the riparian zone, several Lepidoptera (butterflies) are found, such as Glaucopsyche alexis, Pieris mannii, Satyrium ilicis, Maniola jurtina and several moths such as Hyles euphorbiae. Finally in crustaceans, there are populations of the freshwater crab Potamon fluviatile, and especially in sections of continuous flow like in the Valanaris stream. This species is classified as “Near Threatened” (NT) on the red list of the International Union for the Conservation of Nature and Natural Resources (IUCN) [HCMR 2019].

On the banks of the Great River, hundreds of tree species grow such as plane trees (Platanus) and willows (Salix). Also, we can find reeds (Phragmites australis), Typha (Typha latifolia) and many others.

This rich ecosystem of the stream works beneficially for all of Eastern Attica and especially for the city of Rafina. Its natural vegetation filters the pollutants that illegally end up in the stream from the surrounding businesses before they reach the beaches of Rafina, it largely filters the atmospheric pollutants from the port and the airport, it regulates the climate and especially the temperature of the area, it saves the city of Rafina from the catastrophic floods that affect areas with dammed or covered streams, it functions educationally, it is a refuge for the biodiversity conservation.

Rafina's Great River

Cultural Landscape

In the area of Pikermi around the Great River of Rafina lived a rich fauna of herbivorous and carnivorous animals of the plain or the forest. Many of the animals that lived 6.5 – 7 million years ago are new species for science and were given names by researchers that directly remind Attica or Greece such as: Mesopithecus pentelicus, Mastodon pentelici, Giraffe attica, Felis attica etc. Due to the discovery of fossilized animals, which were a milestone for vertebrate paleontology, Pikermi has been characterized since the 19th century as the “Acropolis of Paleontology” and is recognized by the international scientific community as an immense paleontological natural museum. The wider surrounding area has been declared an archaeological site and landscape of special natural beauty since 1983 (OJ B 44/1984). The zone A of absolute protection of Pikermi and the Areas B1 and B2 of absolute and medium protection of landscape, archaeological sites and monuments have also been established in the area by presidential decree (Residential Control Zone of Mesogeia, OJ D 199/2003).

According to the recent archaeological investigations, a high density of ancient technical works, residential remains and cemeteries have been identified in all the riparian areas of the Rafina’s Great River and the associated streams, and in general there are archaeological remains of all periods. Particularly:

  1. In the Municipal Unit of Pikermi of the Municipality of Rafina-Pikermi:
    • Marathonos Avenue – Junction of Valanaris and Rafina’s Great River: Evidence of ancient building remains and a cemetery, parts of an ancient road that coincides in some places with Marathonos Avenue, Mycenaean cemetery with three rows of chambered and box-shaped tombs.
    • Tributaries: All the riparian areas of the streams have extensive residential remains of all periods as well as ancient technical works related to the management of the water volume that passed through their beds.
    • Valanari riverbanks: Ancient irrigation wells and reservoirs, some of them of the quanat type and building remains from the Late Geometric to the Byzantine era.
  2. In the riparian area of Rafina’s Great River in the Municipal Unit of Rafina of the Municipality of Rafina-Pikermi:
    In the southern riparian area of the Great River and in the immediate vicinity of the bed have been identified:
    • Ancient dam with a carved 35m long spillway connected to a water milking well.
    • Ancient water milking wells and cisterns, some of them of the quanat type.
    • Cemeteries of the Geometric and Archaic Periods: The burials extend along the stream and the pits are located in the immediate vicinity of the river bed.
    • Bed of the Great River: On the bed at the height of the Roman Βalneum (Valaneio), a well has been excavated for the expansion of the quanat system. In the same spot there are remains from the foundation of a Roman aqueduct that connected the two coastal areas.

As can be seen from the digital map, the bed of Valanaris is in contact with Area B1 of absolute landscape protection, archaeological sites and monuments of Pikermi.

The EIA falsely states that the project area is entirely outside places of archaeological interest, monuments and landscapes of special natural beauty. This statement was found incorrect by the competent department of the Ministry of Culture which requested its deletion and the correction and completion of all chapters of the EIA as follows: the project is expected to affect the historical and cultural environment of the study area and the cultural heritage and “according to recent archaeological investigations, part of the settlement projects of the Rafina River are located on ancient ruins”. These observations were not implemented and to date the EIA has not been amended accordingly.

Information from the Report of the Ministry of Culture & Sports, 2018.

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