Geoscience Reference
In-Depth Information
Fig. 9 Hydraulic jump at the
interface between deposition
and free bed in the lined
Alpbach and standing waves
propagating downstream of
the hydraulic jump
Aare
deposition
zone
deposition
front
no
deposition
Alpbach
between the rough and lined bed, however, are only observable as long as the
channel beds are not completely covered by sediments. Covering of the channel bed
leads to similar roughness in both bed configurations and accordingly to similar
water and energy levels.
The model tests further showed that the planned confluence with an angle of
approx. 20
(Fig.
1
(3)) works well for all examined combinations of discharge in
the two rivers, generating only small shockwaves. The outlet dam (Fig.
3
(8)) of the
sediment retention basin (Fig.
3
(7)) has been optimized by building a symmetric
inflow trumpet which provides a continuous flow without breakaways at the dam. If
the sediment retention basin is aggraded, a drop at the outlet dam is established. The
energy dissipation at the drop generates a high stationary wave involving scour
protection in the rough bed configuration.
5 Conclusion
The physical scale model Meiringen is a complex system. The two merging
mountain torrents, with different discharge and sediment hydrographs, require
correct and time-dependent regulation of the input parameters. Due to the many
