Nature-based Restoration of a Mountain Stream Habitat: A Case Study from Shangshi Village, Fujian, China

Traditional riverbank engineering typically involves vegetation removal and channelization measures (e.g., bank hardening and riverbed grading), which simplify the natural flow regime and significantly reduce biodiversity. This study focuses on a mountain stream in Shangshi Village, located in the upper reaches of the Baxi River within the Yong'an City water source protection zone, Fujian Province, China. The area is characterized by excellent water quality and rich aquatic biodiversity, notably the annual summer migration of native fish species. However, flood control interventions involving bank hardening and riverbed grading have homogenized the flow regime, leading to the loss of this migratory behavior. Successful fish migration depends on a combination of hydraulic and geomorphic conditions, including suitable water depth, flow velocity, substrate composition, diverse flow paths, and the presence of specific hydraulic cues. To restore the riverine habitat, this study employs UAV-based aerial photography, hydrological surveys (including discharge, velocity, and depth measurements), and field investigations of streambed composition and riparian vegetation. Integrated with hydrological and hydraulic analyses, a rehabilitation scheme combining riprap structures and vegetative engineering is proposed. The approach aims to reconstruct bank morphology and diversify flow patterns and habitat niches, thereby promoting systematic river ecosystem restoration through nature-based solutions.