In the framework of the project Sediment and Habitat Dynamics, 12 questions from authorities and practice were answered.
1. Heterogeneity of sediments
Why does sediment heterogeneity matter at all? What degree of sediment heterogeneity is needed in order to re-establish important ecological processes at the river bottom?
2. Sediment thickness
How does the thickness of the sediment layer affect ecological functioning? To what depth do fish and other aquatic organisms use the sediment?
3. Improving spawning habitat for fish by local gravel additions
What is the ecological success of such measures in small streams? A mini-review of the scientific literature
4. Designing gravel additions
What types of gravel additions in lowland rivers and alpine streams have been implemented so far and what lessons have been learned?
5. Constructing and maintaining bedload traps in areas of particular ecological importance
What are the requirements in these important areas? How should trap maintenance look like in order to guarantee optimal conditions for aquatic communities?
6. Reservoir flushing and ecological effects
What is the impact of water and sediment pulses on sediment transport and morphology in rivers?
7.Bedload trap vs. river widening
What criteria should be used to decide between a bedload trap and a “deposition area”?
8. Bedload management and river rehabilitation (1)
Should soil material that was excavated during river rehabilitation be deposited in the local river corridor/river bed?
9. Bedload management and river rehabilitation (2)
How do fine sediments adversely affect morphodynamic processes and aquatic communities in rehabilitated rivers?
10. Riparian vegetation connected by stepping stone areas
What are the ecological requirements for floodplain vegetation in “stepping stone areas”?
11. Width of riparian area
How does a riparian area look like? What are the ecological and legal requirements regarding minimal and optimal width of riparian areas?
12. Induced bank erosion
What types of artificial structures exist in order to deflect the current in rivers and what are their effects on the river banks?