Brief project information:
| The location: | Grand Western Canal, Devon |
| The project: | To dredge more than 100,000m3 of silt from the canal, in four separate stages, to reduce weed growth and protect the wildlife. |
| Timescale: | Winter 2001 (in stages) to 2006 |
| PDF: |  Download case study - The Grand Western Canal |
“Blue Boar were responsible for project managing the dredging process and the whole land restoration element. They have been very good at working with the local landowners.”
Mark Baker, Canal Manager, Devon County Council
The location:
The Grand Western Canal dates back to 1814, and runs from Tiverton in the heart of Devon through to a small hamlet called Lowdwells near the Somerset border. There are 24 bridges, an aqueduct, a tunnel, two limekiln complexes, nine milestones, historic wharves and a disused lock on the canal with a towpath running along its 18 kilometre length.
Fed by fresh water springs, it is home to an abundance of wildlife - a wide variety of fish, dragonflies, swans, herons, kingfishers, otters and butterflies.
The project:
The canal had been disused for many years and whilst some essential dredging work had been carried out in 1971 when it was bought by Devon County Council, it was then left until 2002. As a result, it had become very shallow in places and this was causing problems for boats and for anglers, who have traditionally fished the canal for tench, bream, perch, roach and pike.
Nutrients in the silt were also encouraging weeds, and because weeds use up oxygen, the fish were dying of asphyxiation, especially in hot weather.
Why Blue Boar?
Devon County Council operates a policy of sustainable canal management and dredging - so the silt removed needed to be transferred to adjacent farmland to provide agricultural benefit for local farmers.
Our knowledge of land restoration meant that we could liaise with local farmers and manage the whole process – removing the stones and mixing it into the top soil before seeding the land with the chosen crop.
The challenges:
- Funding was applied for and awarded but only became available in stages. This dictated how much work could be done at any one time, so we tendered separately for all five phases and were successful each time.
- During one of the phases, we discovered the remains of a crashed Canberra Bomber in the canal! Unfortunately, fuel from the aircraft had soaked into the silt and made it unsuitable for land restoration. We removed the affected material and set up an earth-banked, plastic lined holding area in a nearby car park. Once it had dried out, we removed it to a suitable landfill site.
- Due to budgetary constraints, we used long-reach excavators wherever possible. These are more cost-effective than floating excavators on pontoons which were only used where the canal was wider or the bank was less accessible.
“Our tender decisions are generally based on cost, but I’d also say that we are very happy with the quality of Blue Boar’s work and their flexibility.”
Mark Baker, Canal Manager, Devon County Council
The outcome:
In total, more than 100,000m3 of silt was removed. The dredging all took place between late Autumn and early Spring to cause minimal disturbance to the wildlife.
We moved up and down the length of the canal rather than working on one section at a time; this allowed the dredged part to re-establish itself with colonisation from the surrounding, undisturbed sections.
There is now more boating activity on the canal (including a 100m stretch of long-term moorings) and the future of a traditionally painted horse-drawn barge, the only one of its kind in the West Country, has been safeguarded.
Public sector and Large commercial contracts
In this section
- Droitwich Barge Canal
- River Weaver
- The Grand Western Canal
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