A NEW wall and railings costing around £800,000 is to be build around Edinburgh Castle to protect passers-by from falling rocks.
The wall and additional railings will be shorter than the current structure and cheaper than an initial £1.2 million estimate previously made.
Historic Environment Scotland (HES), the new body formed from Historic Scotland and the Royal Commission on the Ancient and Historical Monuments of Scotland (RSAHMS), is working with the council in the aftermath of a public consultation on a solution to falling rocks.
The structure will have a one metre high stone boundary wall with 1.5 metre metal railings on top.
The current structure is three metres high but closer to the Castle. The new barrier will include a rock trap and gravel blanket.
Barbara Cummins, director of heritage management for HES, which manages Edinburgh Castle, said: “It’s important the public are assured we have no immediate concerns regarding the rock face.
“However, as impenetrable as the Castle Rock might appear, it’s not immune to the effects of the weather.
“The constant freeze and thaw during the winter months can open up cracks in the rock face, which then allows a plant known as valerian to take root.
“Once this germinates the bulb expands and, over long periods of time, this process can cause rocks to fracture and fall.
“At the moment we have a temporary structure in place which offers significant protection, and we supplement that by having our highly-trained staff abseil down the rock on a regular basis to remove loose fragments from the surface.
“While these measures help minimise risk of rock falls, the regular monitoring and scaling is time-consuming and disruptive to visitors to the Castle and drivers on Johnston Terrace, which has to be closed while work is being carried out.”
She said the new rock trap would enhance the risk control arrangements and reduce disruption.
Work begins on October 12 and is due to be finished in March 2016.
The temporary barrier was installed in 2013, after several rock falls from the basalt cliff face in the Johnston Terrace area in August 2012 when vehicles were damaged.
There have been five rock falls in recent years, leading to the need for a “proactive” approach, said historic bodies.
There will be some traffic and parking disruption on the lower section of Johnston Terrace, with one side closed during the project.
Traffic will be restricted to one direction – downhill or westward bound – with no access from the West End except for emergency vehicles. Coach parking will be restricted on some parts of the street but car parking should not be affected. The upper section of Johnston Terrace should not be impacted by the traffic management plan.
Experts previously denied firework displays and flypasts for the Tattoo were to blame for damage to Castle Rock, saying it was down to weather and vegetation.
Metal netting was previously installed on part of the Princes Street face to protect the railway line but this was dismissed as a permanent solution for this work.
In August 2012, a “shoebox” sized chunk of rock damaged two vehicles on Johnston Terrace. Two years earlier, heavy rain sent down a large boulder, narrowly missing motorists.