Today's Cheonggyecheon can create the impression that a natural valley stream has always survived intact in central Seoul. In the Joseon period, however, it was commonly called *Gaecheon*, meaning the open stream or channel. It gathered runoff from surrounding mountains and valleys and carried it east beyond the city walls. Its flow was strongly seasonal: shallow during dry weather and capable of rising rapidly after heavy rain.
Household wastewater and refuse also entered the stream
In a city without separate modern sewer systems, Gaecheon received not only rainwater but wastewater and refuse from homes and markets. Beneath its bridges and along its banks, people washed clothes, moved goods, traded, and rested. The same spaces also suffered from foul smells, pollution, and flooding. Nostalgia for a pristine old waterway cannot explain the environmental conditions endured by people who lived beside it.
*Juncheon* was a major public project to dredge the streambed
Flood damage worsened when deposited soil and discarded material obstructed the channel. The Joseon government mobilized labor and funds to excavate the bed and repair its embankments, a practice known as *juncheon*. The large-scale dredging undertaken during King Yeongjo's reign is a notable example of the state organizing the capital's residents and workforce. Where the excavated soil would go and who would bear the labor were administrative questions in their own right.
The waterway also divided social groups and neighborhoods
Cheonggyecheon helped define living areas known as the upper, middle, and lower districts, whose terrain, occupations, and social composition differed. It separated northern and southern parts of the city while bridges and markets continually brought people across it. Read the stream not as empty space cutting through Seoul, but as a social boundary that organized movement, work, sanitation, and daily life.