The donation of some unused rolls of geotextile has helped a local recreation group in the North-east to build a scenic cycle route. Natalie Hardwick reports.
The rugged natural profile of the Kielder Water and Forest Park in Northumberland, one of the UK’s largest, means the 650km2 area is a popular haven for sports enthusiasts, particularly cyclists.
As an extensive network of off-road tracks grew through the thick working forest and man-made lake, local charity the Kielder Trail Reavers (KTR) wanted to create a permanent cycle path.
Sounds simple enough, but the voluntary group needed to create a bike trail that was solid and inexpensive while having as little impact on the surrounding environment as possible.
The task was not made any easier by the sensitive soil profile in the area - a combination of marshland, bog and large areas of moss and peat.
Local software engineer and chairman of the KTR, Chris Tait, led the project.
“The ground conditions at Kielder are complicated to say the least.
Deep waterlogged peat is very common and it was no surprise that the area we intended working in was going to turn up challenges,” he explains.
“In the current economic climate it was obvious that a big budget project was never going to be forthcoming,” he adds.
“However, we felt that this could add to the project - a ‘hand built’, low budget mountain bike trail could offer a great riding experience by keeping it more intimate than would otherwise be the case if using excavators to construct it.”
The structure of the path and its foundations were considered carefully.
“The path now safely sits on the soils and any subsidence load is spread evenly and mitigated by the textile. This means the path is likely to last longer”
To enable year-round cycling ordinarily would have required the removal of topsoil to place around 150mm of sub-base to provide the starting point of the path construction.
Drainage would then be installed where required and then a capping layer of around 50mm of sub-base and consolidate.
But this was prohibitively expensive.
One cheaper alternative to combat the path sinking into thick moss and peat was to use a geotextile, so the charity approached geosynthetics companies and secured a donation of Terram geotextile.
Martin Lambley, marketing manager of Fiberweb Geosynthetics, who dispatched the Terram material, says they were pleased to help with a community cause.
“We were approached by the KTR and were happy to give away three rolls of Terram 700UV.
It had been in stock for over a year so was readily available to give away,” he says.
“It also happened to be the exact width they were looking for, 500mm x 600mm,” he adds.
A team of around 20 volunteers is laying the path with work done mostly on a once-a-month “build day” and any additional effort put in around that.
After clearing the area, the Terram is laid along the route with 3-4m lengths cut from the roll and laid on an overlap of around 200m.
At these junction points the direction of the trail can be changed to retain a natural feel.
With a floating base on the soft forest floor, the team brings in stone by wheelbarrows to lay on top of the geotextile and which is spread evenly with rakes.
A drainage pipe and channel were positioned and dug at a particularly wet section at the beginning of the trail.
“The textile provides a false bottom for the stone to sit on,” Lambley explains. “The path now safely sits on the soils and any subsidence load is spread evenly and mitigated by the textile. This means the path is likely to last longer.”
Terram 700UV is lightweight and thermally bonded rather than woven and commonly used on roads, pavements, drainage and filtration works.
It is a flat textile, meaning there is more volume in each roll. “The fabric has lots of depth yet it is lighter and volumetric,” says Lambley. “This means it can be shipped in higher quantities as it can fit in the cargo better.
“Although it is a fairly traditional approach in the world of geotextiles - therefore I would be reluctant to compare it to other similar products - it does offer environmental benefits as it replaces the use of natural materials such as when sand filters are used,” he continues.
“Less stone is needed (for the road or path itself) so it is also good for the environment.”
Most of the path has now been laid in time for a summer of cycling pursuits.