Test of Some Selected Stream-Restoration Techniques Adapted to Mid-Slope Urban Streams in Korea

This paper describes the second stage of a research project on stream restoration, focusing on the mid-slope (1/500) urban streams in Korea. The first stage of the research was on the steep-slope (1/300) urban stream, which was conducted at an upper reach of the urban stream, the Yangjae-cheon, south of Seoul. In this second stage of the research, various designs of the so called "close-to-nature" stream improvement techniques were implemented on a test reach of 300m long and 50m wide of the same stream. The riparian habitat and stream scenery was expected improved. In connection with those techniques, special emphasis was put on the test of an on-site stream-purifying device. The device, buried beneath the stream corridor, uses a cobble-contact oxidation method for removing SS and BOD from the polluted stream water. The implementation of the test study began in September 1998 and ended in December of that year. Monitoring of the test reach in term of physical, chemical and biological parameters have continued since the implementation. Floods during the summer of 1999 caused an unexpected sandbar formation in the channel. This result clearly showed the importance of predicting micro-scale morphologic changes when conducting stream restoration.