This study was carried out to evaluate the restoration effect in the restored Yangjae stream and to draw up an adaptive management plan based on the results. As the result of evaluation on the restoration effect, the restored Yangjae stream was evaluated with low naturalness in both terms of the morphology of the stream and the composition and spatial distribution of vegetation. The diverse functional groups were introduced in the vegetation restoration, but the flooding regime, which is significant in the spatial distribution of riparian vegetation, were not correctly reflected. Exotic species or species that were not ecologically suitable for the location were introduced on the embankment and thus a measure to improve those problems is required. As the ecological principle was not reflected in the restoration plan, the stream was constructed as the double terrace structure. Therefore, the width of the waterway was narrowed further, and the waterfront was not designed to accommodate changes from flooding disturbance, making the micro-topography of the stream simpler and the naturalness lower. The adaptive management plan was prepared to improve those problems, and a plan for creating an ecological network was recommended to enhance the restoration effect.

We were conducted to know the community structure the insect fauna of the Cheonggyecheon, the urban natural restored stream. From 2007 to 2010, we were surveyed 18 times at 4 collecting sites, day and night. A total of 352 species of 99 families belonging to 11 orders were identified from 4,433 individuals collected terrestrial insects. Among them, 113 species, 52 families, 9 orders were collected in night time. Grouping by order, these 3 orders, Hemiptera (70 species in 20 families), Lepidoptera (69 species in 19 families) and Coleoptera (67 species in 17 families) were recorded high species number rather than the other orders. A yearly species number are as follows: 137 species, 57 families belonging to 10 orders were recorded in 2007; 162 species, 56 families belonging to 8 orders were recorded in 2008; 159 species, 61 families belonging to 9 orders were recorded in 2009; 166 species, 71 families belonging to 10 orders were recorded in 2010. The species number of lower stream (170 species, 53 families belonging to 8 orders from St.3 and 208 species, 67 families belonging 10 orders from St.4) was higher than that of upper stream (94 species, 47 families belonging to 8 orders from St.1 and 110 species, 48 families belonging 9 orders from St.2). The results of this study showed that diversity of the insect species in Cheonggyecheon have been keeping stable condition since 2008 after 3 years from the Cheonggyecheon restored. Accordingly, Cheonggyecheon is important habitat for terrestrial insects living in an urban environment which has severe ecological disturbances.

The stability of the river in the restored river is an important issue in maintenance and management. Bed elevation change simulation can be an effective way to predict the direction of river restoration by predicting long and short term bed elevation change of river. A 2D numerical model (CCHE2D) was implemented to simulate the long-term bed elevation change. The study area is located in the Cheongmi-Cheon Notap-ri and 1.2 km long. The flow scenario was constructed using the flow data that was measured at the water level observatory located upstream at the Janghowon Bridge. The bed elevation change pattern according to restoration of abandoned channel was analyzed and the stability of river was evaluated.