Stegbach Pendulum Ramp

The Stegbach, a stream flowing into the Aare on the left bank, was redesigned as part of the Olten – Aarau section of the Aare Flood Protection and Revitalisation Project. The existing concrete sill was converted into a pendulum ramp which is passable for fish and which was installed directly at the confluence with the River Aare. The stream was widened at the ramp and the river bank was restructured using rootstock and shrubs. The riverbed between the bars is not secured so that various riverbed structures (e.g. scour undercurrents of the bars) can develop. The pendulum ramp also promotes a healthy aquatic habitat. The Stegbach is a potentially important spawning ground, especially for fish coming up from the River Aare.

Main Data

  • Total drop: H = 1.7m
  • Drop of each bar: H = 0.17m
  • Number of pools: n = 11
  • Total length: L = 68m
  • Average gradient: I = 2.5%
  • Maximum gradient: I = 3.4%
  • Design flow: HQ100 = 30 m3/s


Solothurn Canton, Department of Environment


IUB Engineering AG

Construction period


Scope of services

SIA-phases 31-53