Flood Protection River Langete and Tributaries

Following the floods in 2007 three communities Huttwil, Rohrbach und Madiswil decided to jointly tackle flood protection. The aim is to implement coordinated measures in the three communities step-by-step while optimising costs. The measures include constructing two flood control reservoirs, expansion of a side channel and a  driftwood screen. The flood control reservoirs and the expansion of the side channel  are designed based on a protection goal of  HQ100 .

Main Data

Flood control reservoir Brand (unregulated):    

  • Retention capacity: 120,000 m3
  • Retention effects: HQ100 = 79 m3/s, HQ100,Retent. = 52 m3/s
  • Design-basis flood: QB = 160 m3/s
  • Probable maximum flood: QS = 240 m3/s

Flood control reservoir Tschäppel (unregulated):

  • Retention capacity: 100,000 m3
  • Retention effects: HQ100 = 30 m3/s, HQ100,Retent. = 12 m3/s
  • Design-basis flood: QB = 60 m3/s
  • Probable masimum flood: QS = 90 m3/s

Side channel expansion:

  • Numerous coordinated defence measures (raising level of banks, ground modelling, bridge adjustments, etc.), which were developed in consultation with the landowners
  • Numerous coordinated defence measures (raising level of banks)
  • Length of channel: 100,000 m3


Municipalities Huttwil, Rohrbach and Madiswil


IUB Engineering AG in Consortium

Construction period


Construction costs

CHF 13.7 million

Scope of services

  • Construction project
  • Approval process
  • Tendering