The deployment of spur dike group improves physical habitats in urban meandering rivers: Insight from a 2D habitat suitability model

•A dedicated standalone piece of software for fish habitat simulation was constructed.•Spur dike deployment enhances physical habitat quality and quantity in bends.•The deployment of dike group reduces ecological flow demand by 25%.•Combination of spur dikes and bend flow optimizes habitat improveme...

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Bibliographic Details
Published in:	Journal of hydrology (Amsterdam) Vol. 638; p. 131541
Main Authors:	Cai, Yujie, Zhang, Xinhua, Liu, Junzheng, Tir, Yasmina, Cao, Daling, Zhang, Zhuo, Guo, Yijun, Zeroual, Ayoub
Format:	Journal Article
Language:	English
Published:	Elsevier B.V 01-07-2024
Subjects:	Aquatic habitat Environmental flow evaluation model Spur dike Urban bend river Spur dike Environmental flow evaluation model Aquatic habitat Urban bend river
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Summary:	•A dedicated standalone piece of software for fish habitat simulation was constructed.•Spur dike deployment enhances physical habitat quality and quantity in bends.•The deployment of dike group reduces ecological flow demand by 25%.•Combination of spur dikes and bend flow optimizes habitat improvement. Although channel meandering is currently a popular approach for river ecological restoration, the spiral flow formed in bends may lead to fragmentation of aquatic habitats due to the concave bank erosion and convex bank sedimentation. The aforementioned issue motivated this study, which aims to mitigate the adverse effects of curved flow on aquatic habitats within bends. We proposed a placement strategy of dike group within the curved channel to adjust the water–sediment structure of meandering rivers, thereby safeguarding against bank erosion and the fragmentation of river habitats. The effectiveness of this strategy has been validated by the development of numerical models based on 2D depth-averaged water–sediment equations, coupled with the IFIM method. These models investigate the mechanism of aquatic habitat enhancement achieved by deploying groups of submerged and non-submerged dikes on the convex and concave banks of the Fuhe River in Chengdu, China. The findings indicate that the implementation of dike groups resulted in an enhancement of approximately 30% in the weighted usable area (WUA) of the specific river. This improvement was accompanied by a 25% decrease in the ecological flow threshold (WUAmax). Furthermore, subsequent comprehensive comparative analyses under various conditions revealed that the fluctuations in enhancement effects were mitigated by flow increases. The degree of submergence parameter exhibits heightened sensitivity to enhancement effects, especially when the flow remains below the ecological threshold. The findings of this study can serve as a reference for the ecological restoration of river systems.
ISSN:	0022-1694
DOI:	10.1016/j.jhydrol.2024.131541