.png){kind=icon}
.png){kind=icon}
Return
Hydrodynamic and ecological effects of engineered logjams: Insights from field observations
.png){kind=icon}
OA
AI
F
C
I
DOI：10.1002/esp.70322.png)
.png){kind=icon}
Original request for help.png){kind=icon}
Share.png){kind=icon}
Save
Abstract
En 中文
Engineered logjams are widely applied in river restoration to increase flow heterogeneity and create aquatic habitat. Laboratory studies have provided insights into the hydraulic effects of engineered logjams under controlled conditions, but field-based quantifications at full scale remain rare. This study investigates the hydrodynamic, geomorphic and ecological effects of engineered logjams in a restored 730-m section of the Emme River in Switzerland. Large-scale particle image velocimetry was applied at two engineered logjams to resolve the spatial structure of the surface flow field. The results show that engineered logjam size and placement strongly influenced jet velocities, wake characteristics and local scour formation. Lower discharge increased velocities in the gaps but had little effect on wake length, suggesting that downstream habitats may provide stable refuge across a range of flow conditions. Morphological mapping with drone imagery highlighted the strong influence of a one-year flood, which mobilized sediments, reshaped banks and partially buried some structures. These findings demonstrate the dynamic feedback between flow, sediment and wood in the early post-restoration phase. Electrofishing surveys indicated a nearly tenfold increase in fish abundance following restoration. Moreover, the post-restoration fish community comprised predominantly native species. However, the continued absence of several native species expected in this river section suggests that, although engineered logjams and channel widening enhanced overall habitat availability, they did not directly promote the recovery of all target species. The integration of drone imagery, large-scale particle image velocimetry and fish surveys demonstrates the value of multi-scale monitoring for evaluating restoration projects. Beyond confirming trends known from laboratory studies, our findings highlight site-specific processes such as flood-induced morphological change and the nuanced ecological outcomes of engineered logjams.
Keywords:
flow heterogeneity
habitat connectivity
large-scale particle image velocimetry
morphological change
river restoration
turbulent flow
Journal
IF:
2.7
Papers:
324
Citations:
1.5W
Organization
Cited Papers