Himalayan balsam, Exeter Flood Defence Scheme Phase II

The brief

Following a competitive tendering process, we were awarded the Himalayan balsam remediation package by BMMJV (a joint venture between BAM Nuttall and Mott MacDonald), for works on the Exeter Flood Defence Scheme Phase II.

The £32m Exeter Flood Defence scheme for the Environment Agency involved the construction of flood defences on both banks of the River Exe from Cowley Bridge to Countess Weir.

The defences include walls, banks, demountable weirs, gates and glass panels with extensive landscaping and habitat creation also taking place.

What we did

  • Mechanical clearance of 7 hectares of Himalayan balsam along the River Exe using a combination of brushcutters and an excavator-mounted flail. Care was taken to ensure that the Himalayan balsam was cut below the lowest growing node
  • Application for Environment Agency herbicide spraying permissions
  • Spraying 7 hectares of re-growth along the banks with herbicide
  • Providing advice and input into fortnightly environmental progress meetings
  • We used our bespoke interactive mapping service –TIM, so that the client and the project team could track progress and see the areas where Himalayan balsam was or had been present. This is important because it means that any future works involving interfaces with contaminated areas can be properly planned.

Our Covid-19
Business Response

Find out more