Ecological Health Assessments of an Urban Lotic Ecosystem Using a Multimetric Model along with Physical Habitat and Chemical Water Quality Assessments

The objective of this study was to diagnose integrative ecological health of an urban stream,which is located in the Asian temperate region. The research approach was primarily based on the Index ofBiological Integrity (IBI) using fish assemblage and a Qualitative Habitat Evaluation Index (QHEI). And these indexes were compared with long-term conventional chemical dataset during 1996-2005. For the experiment, four sampling sites were chosen from the stream and wading method was used for fish collection during 2004-2005. We developed a stream health assessment model (SHA model) for the regional application. Stream health conditions, based on the SHA model, averaged 23 indicating a fair-poor condition, and varied from 18 to 40 depending on the sampling stations. Values of QHEI varied from 55 (fair-poor condition) to 112 (good-fair condition) and the values were significantly lower in the down stream than the headwater. Water quality, based on COD, BOD, TN and TP declined from the upstream to downstream reach. The proportion of sensitive species showed a negative linear function with BOD and the tolerant was vise versa. Values of SHA model reflected the chemical and physical habitat conditions and this result was clearly evident in the downstream reach. These outcomes were supported by principal component analysis (PCA) of IBI vs. other factors. Overall these results suggest that the impacts to the health of this stream are due to the combined effects of both chemical and habitat degradation.