Pendulum Ramp and Revitalisation of the Stegbach

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 were 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. An approx. 200 m long section above the ramp was revitalised along the bank line using compressed gravel filling, large deadwood structures (felled trees, rootstock) and shrubs. The gravel and structures were placed in such a way that a rifflepool sequence develops.

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 Neigung: I = 3.4%
  • Design flow: HQ100 = 30 m3/s
  • 3 gravel fillings à 15m3
  • 30 inserted rootstocks


Solothurn Canton, Department of Environment


IUB Engineering AG

Construction period


Scope of services

SIA-phases 31 - 53