Search results for "River restoration"
showing 6 items of 6 documents
Connectivity of urban rivers and environmental justice
2018
With the explosion of urban waterfront revitalization projects in the developed world, it is timely to reflect on the relations between cities and their rivers: how the rivers influenced development of the cities, how cities have treated their riverfronts since 19th century, and how the spatial relations of city and river constrain and enable improved connectivity between urban populations and their rivers. Both celebrated as revitalizing neglected urban centers and criticized for displacing the disenfranchised populations, riverfront revitalization projects raise questions about what constitutes ‘restoration’ in cities, to what degree natural processes and ecological values can be restored…
Mean flow, secondary currents and bed shear stress at a 180-degree laboratory bend with and without enhanced permeable groins as an Eco-friendly rive…
2022
River restoration aims to apply environmentally-friendly structures for bank protection in meandering rivers to restore their natural habitat. Enhanced Permeable Groin (EPG) is a novel river restoration technique that can improve the fish habitat environment in a river system by creating a series of eco-friendly scour pools. This study reports the results of two groups of 3D velocity measurements in a 180-degree channel bend in cases with and without an EPG for clear water conditions to characterize the mechanisms leading to the primary stages of the scouring phenomenon. The analysis revealed that the presence of an EPG amplified the velocity magnitude in the regions near the tip of the van…
Synthesis of habitat restoration impacts on young-of-the-year salmonids in boreal rivers
2019
River restoration offers the potential to enhance biological integrity, often measured as fish population changes. We used a meta-analytical approach to synthesize density responses to in-stream habitat restoration by young-of-the year (YOY) brown trout and Atlantic salmon in 28 rivers (overall 32 restoration projects) in Finland. We also examined which local and watershed-scale factors most influenced restoration success. Finally, we conducted an expert survey to obtain an independent estimate of a sufficient density enhancement for restoration to be considered successful. Despite strong context-dependency, habitat restoration had an overall positive effect on YOY salmonid density. When co…
The success of crayfish stocking in a dredged river with and without artificial shelter increase
1997
Abstract The success of crayfish ( Astacus astacus L.) stocking in a heavily dredged river in Finland was compared between sections with and without artificial shelter. The materials used for creating shelter were a) broken rock and, b) ceramic drain pipes and perforated bricks. Group-marked crayfish (mean carapace length 42.6 mm) were released into the sections and test trappings conducted one year later. The highest crayfish densities were found in the broken rock sections. The reasons for the observed crayfish densities are discussed. No significant differences in growth between groups were detected. Migrations in the range of 2.5 km in one year were recorded.
Effect of river restoration on life-history strategies in fish communities
2019
Assessments of river restoration outcomes are mostly based on taxonomic identities of species, which may not be optimal because a direct relationship to river functions remains obscure and results are hardly comparable across biogeographic borders. The use of ecological species trait information instead of taxonomic units may help to overcome these challenges. Abundance data for fish communities were gathered from 134 river restoration projects conducted in Switzerland, Germany and Finland, monitored for up to 15 years. These data were related to a dataset of 22 categories of ecological traits describing fish life-history strategies to assess the outcome of the restoration projects. Restora…
Investigating the Performance of Enhanced Permeable Groins in Series
2020
The enhanced permeable groin is a novel eco-friendly and cost-effective technique for bank protection and restoration of meander bends. The behavior of bed deformations due to the distance between the structures has to be studied to design enhanced permeable groins in series properly. In this study, scour morphologies around enhanced permeable groins in series, characterized by four different distances and located in a 180°