This study determined the habitat suitability index (HSI) for fish by using a two-dimensional hydraulic model. The segment of a river at Dashin Village was simulated. The first step was to identify the fish species, calculate
the importance relative index (IRI), and select the target species. An unmanned aerial vehicle (Mavic pro) was then
employed to obtain photographs and output orthophotos and digital surface models. Next, the velocity and depth of the
surface before and after construction were simulated, and the HSI of the fish (Taiwan shovel-jaw carp) was calculated.Finally, the Kriging method was employed to interpolate the distribution of the HSI, and the area size before and after improving the engineering was evaluated.
Keywords: Hydraulic model, habitat suitability index, digital surface model