Current status of Korean streams and exploring areas with high necessity for stream structure restoration

¹ Department of Biological Science, Pusan National University, Busan 609-735, Republic of Korea
² GIS Strategic Planning Department, GIS United Inc., Seoul 120-760, Republic of Korea
³ Department of Geographical Information System Engineering, Namseoul University, Cheonan 331-707, Republic of Korea
⁴ School of Computer Science and Engineering, Seoul National University, Seoul 151-721, Republic of Korea
⁵ Department of Environmental Education, Suncheon National University, Suncheon 540-742, Republic of Korea
⁶ Nakdong River Environment Research Center, NIER, Goryong 717-807, Republic of Korea
⁷ Department of Environmental Science and Engineering, Kyunghee University, Yongin 446-701, Republic of Korea

^* Corresponding author: lter.ecoinfo@gmail.com

Received: 2 September 2010
Accepted: 5 March 2011

Abstract

Stream restoration is an important process affecting the ecological health of stream ecosystems. There have been numerous cases of restoration, dealing with either structural or biological changes. In Korea, most restoration projects have merely dealt with improving hydrological characteristics or water quality; however, in recent years the improvement of ecological characteristics has been an increasing focus for restoration projects. In this study, we utilized data collected from 5675 stream sites in May 2007 to discover general patterns of anthropogenic modification in Korean streams. The survey results after application of the stream modification index (SMI; presence or absence type; high scores indicate more disturbed) provided a general distribution of disturbed/undisturbed streams or rivers in the watershed. We then compared the level of modification with the socio-geographical patterns (population, land coverage, elevation, and slope) for the watershed. The results show that streams in highly populated areas suffered from human modification compared with other well-preserved stream sites. In metropolitan cities, urbanized areas had positive relationship as identified by a high SMI. On the other hand, agricultural land cover identified an SMI increase for lowland river area. In general, mountainous streams possessed a better status in stream morphology due to different land-cover patterns (i.e., mainly forested area); however, some mountainous areas were impacted by concentrated summer rainfall. We could distinguish the forcing variables (i.e., land use pattern) for the disturbed streams through a comparison between the SMI and geographical information; the SMI application was able to identify areas of high necessity for restoration.