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Anecological Restoration Framework for Lowland Flood Channel in Hong Kong

Author(s): Yao Wang, Onyx W. H. Wai

Linked Author(s): Onyx W.H. Wai

Keywords: River ecological restoration, lowland flood channel, habitat quality index, underwater video system, physical habitat modeling

Abstract: This paper aims to provide a framework for ecological restoration on lowland flood channels for the benefit of inhabited fish. The study area of the present research is located in Tung Chung River in Hong Kong, with a channelized downstream section to be restored. In this study, Parazaccospilurus (a widespread endemic fish species) is selected as the target fish as it is sensitive to habitat changes and is commonly found in unpolluted local streams. First of all, taking both physical and fish sampling into equal importance, field survey is conducted in both wet and dry seasons in the study area. A new fish monitoring system specified for lowland flood channel is developed in this study using high resolution underwater camera based on remote underwater video system technology. To establish appropriate fuzzy-sets and fuzzy-rule for modeling the physical habitat of the target fish, the fish daily activities will be monitored and recorded in the laboratory. In addition, the fish swimming velocity and acceleration in an artificial environment with instream structures (e. g. deflectors) will be monitored to investigate the impact of these structures on the fish swimming behavior. The physical habitat model, CASiMiR, will be applied to assess the fish response to changing physical properties based on the fuzzy physical-biota relationships. Finally, in order to attract the target fish back to the lowland channelized section, the water and sediment regime will be modified according to the habitat modeling results. A restoration program focusing on deflector construction will also be proposed to create riffle-pool sequence and meandering based on the effectiveness of deflectors observed in the experiments. It is hoped that the present research could be useful to guide the future development and design of flood channels which are deserved to be protected


Year: 2017

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