A river missing from the present map
Today the Han flows north of Jamsil and the lake looks independent. In the past, Songpa River ran south of sandy Jamsil Island and Sincheon River to its north; Songpa served as the main channel. Songpa District describes the lake as water remaining where the old river and ferry had been after reclamation. Calling it a pond built for Lotte World erases that geography. Its narrow length preserves the direction of a vanished river.
Turning an island into city land
In the 1970s, development blocked the southern channel, enlarged the northern flow and reclaimed public water. Jamsil became connected land for housing, roads, stadiums and commerce. East and West Lakes preserve only portions of the former channel, not the whole river. Project dates vary by administrative phase, so do not describe a single overnight transformation. Most water became urban land while selected surfaces remained as managed lake.
Why East and West Lakes feel different
Songpa-daero and Jamsil Lake Bridge divide the water. Magic Island dominates the west; walking and cultural facilities are more visible in the east. Both share one origin. Under the bridge, changes in sound, light and pedestrian flow show how infrastructure split one waterbody into two activity zones. Comparing them explains more than insisting on a complete circuit.
Nature maintained as infrastructure
The lake depends on water supply, circulation, water-quality monitoring and path maintenance. Level and appearance vary with rain, season and works. Do not assign a low or cloudy surface to one building without current measurements. Past investigations of 2010s water-level decline cannot certify today’s condition. Urban water is scenery and infrastructure requiring continued monitoring.
Read the lost river safely
The official circuit is about 2.5 kilometres, but events and closures alter time. Decks and steps become slippery in rain or ice; blossom crowds may create directed movement. Stay behind rails and avoid sudden stops among runners. Comparing an old map with East Lake, the bridge and part of West Lake reveals the river-to-city transformation without forcing a full lap.