Bristol City Flood Alleviation Tunnel

Wessex Water, the regional water and sewage treatment company for the South West of England, designed a scheme take floodwater from that Kingstown area of Bristol through to the main Northern foul interceptor sewer in the west of the city. Due to the nature of the geology along the proposed route it was decided that an 800 metre long tunnel would be constructed by drill and blast method as the best solution.

The tunnel was planned to run beneath some very sensitive city buildings including Red Lodge, which is Grade 1 listed and also the University of Bristol Royal Fort building which required careful control of blast induced vibration. SES were responsible for the security, transport, use and control of all explosives utilised in the works and successfully blasted through 18000 tons of rock during the project without any incident. The tunnel geology of inclined, interbedded sandstone, limestone, siltstone and mudstone posed quite an engineering challenge, particularly when excavating through the second hardest rock in the UK.

The project was completed on time and within budget and has removed the risk of flooding in this
area.