Restoration of an inner-city stream and its impact on air temperature and humidity based on long-term monitoring data

Spatiotemporal changes in air temperature and humidity associated with the restoration ofan inner-city stream in Seoul, Korea, are investigated based on long-term monitoring data. TheCheonggye stream, covered under a concrete structure for 46 years, was restored in 2005 and runs5.8 km eastward through a central region of Seoul. Long-term monitoring of the air temperature andrelative humidity was made along the stream throughout the restoration and across the stream afterthe restoration. The area along the stream had a higher air temperature than the entire metropolitanarea. The temperature anomaly between the monitoring area and the surrounding metropolitan area was0.13^oC lower on average at the center of the stream after the restoration. The stream's effecton the air temperature was also evident in the temperature distribution along a street traversing thestream. The relative and specific humidities were increased due to the restoration. The restoredstream modified the nearby urban climate in the opposite direction compared to urbanization. Theresults could be used as a model case in mitigating urban climate by a stream in future urban planningpractices.