Author(s): Shu Ishizaki, Shigeya Maeda, Akiko Minagawa, Koji Noda, Hisashi Kobayashi, Koshi Yoshida, Hisao Kuroda
Linked Author(s): Shigeya Maeda
Keywords: Ecohydraulics, habitat suitability, hydrodynamic simulation, reservoir, river
Abstract: Influence of river discharge variation on fish habitat is evaluated using two-dimensional hydrodynamic simulation, HSI (Habitat Suitability Index), and WUA (Weighted Usable Area). The river reach of interest is situated in the midstream of Ane River, Japan, which is affected by upstream flow regulation at the dam and water withdrawal for hydropower generation. An unsteady two-dimensional hydrodynamic model is calibrated and validated with observed data in 2015 and 2016. Quality of the reach as habitat of two adult fish species, Rhinogobius flumineus and Nipponocypris temminckii, is assessed by combining computed hydraulic variables and suitability indices on the fish. Analysis of spatial HSI distribution and WUA variation over discharge ranging from 0. 5 � 50 m3/s reveals that the flow environment in the reach is more preferable for Rhinogobius flumineus than Nipponocypris temminckii. The discharge where habitat begins to decrease sharply in the WUA/flow curve is derived, which could be used as a recommended minimum discharge in view of ecological conservation
Year: 2017