Little bridge over a river that could make a big difference
‘UNCONVENTIONAL’ STRUCTURE DESIGNED TO PROTECT ENVIRONMENT
IT may not look much but this little bridge could make a big difference.
The bridge across the Little Dee in Penaran Forest in Gwynedd is part of the LIFE Dee River programme.
Prior to installation, forestry vehicles had to cross the river by driving directly through the watercourse, leading to its contamination and the potential to harm the spawning grounds of fish and other aquatic animals further downstream.
The new crossing will prevent an estimated 4,000 trips through the river by articulated lorries, with approximately 25,000 tonnes of timber to be harvested and transported over the next five years.
Caulmert, which has offices in St Asaph and Bangor, has been working for Natural Resources Wales (NRW) to plan and design the bridge.
It measures 8.5 metres long and 3.5 metres wide and construction included the use of 10 precast concrete planks for the deck.
After spending four months on the project, Caulmert handed over the plans to NRW to start the build.
Caulmert associate director Peter Dawson, who oversaw a team of three at the design development stage, said: “It was wonderful to be involved in such an important project for the local environment in Gwynedd.
“It is an unconventional bridge of a fairly short span and will be used infrequently, but it still needs to take the weight of 44-tonne articulated lorries.
“We really thrived on creating the most straightforward yet cost-effective design we could.”
Caulmert also devised the streamlining of the embankment and improvements to the access track leading to and from the new bridge.
Peter said: “One challenge was to set the bridge level to minimise the risk of flood impact but also reduce the length of reprofiling of the access road that has to tie into the deck level.
“Each concrete plank was slid in from one end of the bridge and there is no concrete topping, so that maintenance inspections can be carried out more efficiently.”
Tomos Wynne, land management officer for the LIFE Dee River project said: “The bridge will help limit the input of sediments and nutrients from entering the watercourse and will also reduce the chances of any further contaminates from entering the Dee, offering benefits to salmon and other aquatic species found there.
“The work forms part of our wider programme to improve conditions throughout the entire Dee catchment, including weir removals, installing riverside fencing, tree planting, and reintroducing boulders back into the river channel.”
He added: “Working with our contractor, DW Jones, and designer, Caulmert, the plan and build has ensured water quality in the Afon Dyfrdwy, a Llyn Tegid special area of conservation, is protected in the future.”
The LIFE Dee River project is funded by the EU LIFE programme, Welsh Government, Environment Agency, Dŵr Cymru/Welsh Water and Eryri National Park Authority.