Argon Pedion

Argon Pedion (Greek: Ἀργὸν Πεδίον, lit.'untilled plain') is the geological name of a "closed karst basin" in the Arcadian highlands in the Peloponnese peninsula of southern Greece. The first known appearance of this name was in a publication by the ancient geographer Pausanias (110–180 AD). He called it untilled plain, because the grassland and acres may be flooded beyond the time when annual vegetation starts. When the winter rains were very heavy, floods can even turn the plain into a temporary lake. Intensive karst formation (drainage in underground waterways of limestone layers) prevents the formation of a permanent lake. In rare cases, even today, modern technologies can not prevent flooding.

The Polje Argon Pedion. Drainage only by ponor(s)
Peloponnese
Temporary lake in Argon Pedion, A7 motorway. Ditch to ponor (10 tree tops in water, front left)
Totally green in springtime