dc.description.abstract | This research focuses on the habitat conditions of the Fazih River under different channel contraction by Weighted Usable Area (WUA) method. The River 2D model and the HEC-RAS model were used to simulate four channel conditions, namely the original width of river and 10%, 38% and 53% of the original river width contraction. Four species of fish, the Acrossocheilus paradoxus, Rhinogobius candidianus, Cobitis sinensis and Zacco pachycephalus, were chosen as target species.
The result indicates that the four river widths provide similar WUA under low flow condition. However, in the normal flow case, channel with the original river width shows better WUA than that of other channel cases with contractions of river width, among those the 58% channel contraction results the worst case. When WUA decreases and flow increases, the suitable habitat for a certain fish species decreases. In this study, the simulation results show that the Acrossocheilus paradoxus presented the best survival ability because of the highest WUA in all channel width conditions, while the Cobitis sinensis suffered from the lowest WUA. In conclusion, adequate river channels are necessary for habitat preservation, as well as to maintain the flood plain ecologically sound.
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