Silverton Mill, Exeter – River Redirection

Client : D S Smith
Programme : 3 years
Value : £4.5m

As Principal Contractor John F Hunt was required to demolish and remediate a former paper mill, comprising a large number of tightly arranged structures, pipelines, ducts, pits and soak-aways in addition to a large culvert that ran beneath the site.

The former paper mill straddled a major river (River Culm) and had had heavy industrial usage dating back to the 1800s. The river ran through a large culvert (pictured right) for almost the entire length of the site.

Significant pollution issues were present with contamination in the form of heavy and light hydrocarbons and asbestos in the soils.

The remediation of the contamination around the culvert presented a significant problem. Our solution was to construct a temporary river diversion to allow the culvert and surrounding ground to be effectively remediated without risk to the River Culm.

  • Demolition of the above ground structures to ground level to provide sufficient space for the river diversion.
  • Design and construction of the HDPE lined river diversion channel including regulatory negotiation and agreement for the design.
  • Commissioning and maintenance of the river diversion during its operation.
  • Monitoring of the River Culm for prediction of high flow conditions to prevent damage to the works and temporary channel.
  • Demolition and removal of the old culvert beneath the former building.
  • Remediation of the contaminated ground beneath and surrounding the old culvert.
  • Design of a new permanent river channel with enhanced environmental benefits.
  • Construction of the new river channel post remediation, including a groundwater base flow alleviation system, rock armour flow protection and restoration of grassed embankments.

For more information please press here.