An interesting case study in hidden hydrology from a region I’ve yet to discuss, Greece. Via the Telegraph, an article “Athens hatches ambitious plan to uncover fabled river, once the haunt of Socrates, and turn it into a park.” The river in question is the Ilissos, which, due to lack of maintenance on the subsurface tunnel in which the river flows has led to structural issues that has caused issues with the tram line running on the surface, and opened up opportunities for restoration of this ancient waterway. As mentioned:

“An 1821 water colour of the Ilissos River and the Temple of Olympian Zeus” – via Telegraph (image credit Alamy)

“Urban planners have suggested that rather than spending millions of euros on reinforcing the tunnel and repairing the track, the tram line should be diverted along a different route and the river opened up. They are proposing the creation of a park along a one mile stretch of the formerly forgotten river.”

Some context on the significance of this river, via the HYDRIA Project, “Ilissos river was considered in antiquity as the second main river of Athens, forming an horizontal landmark in its southern and eastern sides. Ancient writers mention various activities by its banks, varying from civic processes, cults -including a sanctuary dedicated to the river himself, by Ardittos hill- or social walks and philosophical endeavours in idyllic landscapes, as for Socrates and his disciples (Plato, Phaedrus 229-230, link). “

View of Athens from the River Ilissos – painting by Johann Michael Wittmer – via Greek City Times

Due to the dry climate, the Ilissos and the other river in Athens, the Kifissos, are often dry, as mentioned in the article. “Given Greece’s dry, hot climate, neither is huge – they are nothing like the Thames in London or the Tiber in Rome.” They do, however, act as places for floodwaters to run after winter rains, and the depths can reach up to six feet.

Map of Ancient Athens (Ilissos River highlighted by author) – via Ancient History Encyclopedia

From the BBC “Athens to open up ancient river“, the plan by Nikos Belavilas from the Urban Environment Lab shows the route of the proposed daylighting, restoring it after it was paved over in post-WWII development. You can see the location of the current configuration in the context of the historical routing above, including the Stadium and the Temple of Olympian Zeus, built by Hadrian.

Map of the Ilisos – via BBC (image via Urban Environment Lab)

Beyond daylighting, the restoration also has bigger implications, as a strategy to avoid future issues. As mentioned in the BBC article:

“But it is not just a simple matter of reclaiming the city’s past, but also of saving its present.”If the Ilisos tunnel collapses, it will block the natural course of the river, and could flood the entire city centre,” Mr Belavilas warns – “That doesn’t bear thinking about.”

Currently, only a small section is now visible on its path from the mountains, as mentioned in the Telegraph: “It originates in the mountains on the edge of the city and eventually flows into the Saronic Gulf, after passing almost unseen beneath the streets of the capital. It does emerge briefly, in reed beds behind the Temple of Olympian Zeus, which was built over several centuries starting in the second century BC. “

The only uncanalised part of the bed of Ilissos river that once ran outside the old city of Athens. – via Wikipedia

HEADER: River Ilisos and Stadion Bridge, ca. 1900 – via Wikipedia