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Jackson uses bioengineering to stabilise eroded flood defences

Jackson Civil Engineering is using bioengineering solutions to stabilise eroded flood defences in Lincolnshire.

The project is taking place along the River Steeping at the village of Wainfleet All Saints, which hit the national news in June 2019 when two months of rain fell in three days.

This resulted in a breach in the flood embankment, which led to hundreds of homes being evacuated. Assessment of the embankments found that some had eroded.

Bioengineering

Rather than a hard engineering solution, the Jackson team, working on behalf of the Environment Agency, is installing an environmentally sensitive solution using bioengineering and vegetation re-establishment.

Rock rolls

Workers are installing rock rolls - mesh bags holding coarse gravel - against the embankment at the toe-line. Lengths of coconut coir rolls are then placed on top. These are pre-planted with native riverside plants, such as reed and glyceria.

“This vegetation will help to stabilise the banks because the root systems hold soil in place and act as a natural barrier to erosion,” said Jackson Sub Agent for the project, Gareth Baugh. “In addition, native plants will provide habitat and cover for a variety of species.”

Ecologists

The Jackson team is working closely with on-site ecologists to ensure disturbance to the river’s population of water voles – a protected species – is minimised.

Markers are placed where their burrows are found to alert workers not to place coir matting over these holes. On areas where the erosion is particularly bad and more intensive work is required, the water voles are temporarily displaced from the location.

Jackson’s commitment to minimising disturbance to the local environment has led the team to trial the use of solar panels to power its offices, canteen, toilets and drying room at the site compound.

Gareth said he had been ‘massively impressed’ at the results so far.

He said: “The Solartainer has reduced our carbon footprint by 12 tonnes of CO2 in the past fortnight and cut our use of diesel by 83%. There have also been additional benefits in terms of cost savings and noise reduction on site.”