Test work to slow erosion threatening clifftop homes
TESTS are under way to find a way of slowing the erosion of Barton cliffs, which is creeping towards scores of expensive seafront homes at a rate of one metre a year.
A £200,000 Environment Agency grant has been handed to New Forest District Council to experts research groundwater drainage to make the cliffs – which are prone to landslides and cracking – more stable.
NFDC’s coastal team say the trial is important as it will shape options for a future full-scale scheme to try to protect nearby houses valued at up to nearly £900,000.
Local district councillor Geoffrey Blunden said. “This is an important step forward in the ongoing battle to stabilise the cliffs at Barton-on-Sea and to reduce the rates of erosion.
“I very much hope this trial is a success and can lead to a major drainage and cliff stabilisation scheme, enabling a greater level of protection to the properties and land along this great coastal frontage.”
The NFDC scheme will address the issue of groundwater which, when high, makes the cliffs unstable and causes sometimes dramatic landslips – such as at Taddiford Gap between Barton and Milford where the footpath has been closed for safety reasons, as reported in the A&T.
The Barton trial will test how to manage the problem, using the latest drilling technology and the insertion of a long section of perforated pipe.
The pipe will extend to the bottom of the cliff, targeted to pass horizontally between specific layers of underlying rock to intercept and drain some of the groundwater.
The equipment is due to be installed in the autumn followed by a year of monitoring to assess how the water levels respond and affect the environmentally-designated lower cliff.
Cllr Alison Hoare, NFDC cabinet member for environment, said: “We are pleased to be awarded the funding to carry out this trial, following the recent ground investigations by the coastal team, which showed that this type of groundwater management system was the preferred way forward.
“This important trial will tell us if this is a suitable approach and inform our coastal protection work going forwards.”
Similar to much of the shoreline of Christchurch Bay, the Barton cliffs comprise Palaeogene clay, sand beds and gravel. The relatively weak structure is eroded and undermined particularly by effects of the rain, but also the waves in places, leading to regular landslides.
In 2013, NFDC did a series of ground investigations at Barton into the cliff’s stability, erosion and groundwater which the new trial will build on.