Leeson Road in Ventnor has now closed for several weeks, for borehole works following the landslide of December 2023.

The road had been re-opened through the summer holiday period, under strict monitoring and continual inspection - but now more works need to be done.

Deep borehole drilling will take place in three locations on the road, from today (Monday, September 9). 

Here we look at the key questions around the scheme.

The closed section of Leeson RoadThe closed section of Leeson Road (Image: Isle of Wight County Press)

What is the purpose of the borehole works?

There are two purposes.

The first is to investigate, log and sample the geological layers below Leeson Road, to further add to the data of the area following the landslide.

The second purpose is to then use the boreholes to house extensive monitoring equipment throughout the layers and depths, to return continually available data, that indicates various types of underground movement, groundwater levels and pore-water pressures.

What will the data show?

As an addition to the immediate monitoring needs for Leeson Road, the boreholes will serve to provide additional geological information for other technical consultants and organisations that wish to use valuable, new data to inform studies on further work on the St Lawrence and Bonchurch landslide areas.

How deep will the boreholes be?

The boreholes will be drilled to around 110m deep, with at least one going to 130m deep.

How long will the road be closed for?

The official line is now "up to ten weeks" - as of today (Monday) - which takes us to the middle of November.

Yesterday (Sunday) the council confirmed ten to 12 weeks, and had previously said "before Christmas" - and council leader Phil Jordan has said five to six weeks.

However no decision can be made to open the road until the drilling allows for the first set of data to be analysed.

Why close the road now?

The council is aiming to get the work done before winter season with increasing rainfall possible as the months go on.

Why can't the road be opened during evenings, or open one-way like before?

The specialist works of deep drilling in a potentially fragile environment can only be completed in the daytime. But the scale of the rig and wider safety area means the public must be excluded at all times for health and safety reasons.

A specialist rig needs to be set up, and the safety zones around the equipment, and the required exclusion of people from the area, is a fundamental part of the work.

The ideal safety area is 6.5m, which is already wider than the available road width of 5.8m to 6.2m.

It is not possible to have vehicles passing the rig within the exclusion zone.

Even site personnel are excluded from the area with the rig operators being the only exception.

It is not possible to do a daily de-mobilisation of all the equipment to an adjacent site or safe compound. This could take up to four hours each day - extending the project well beyond the currently planned 12 weeks - and has additional risks attached.

Can emergency vehicles pass through the road closure, as they did before?

It will not be possible for emergency vehicles to proceed through the site.

There have been parking suspensions along parts of the diversion route to aid traffic flow.

For example, on Newport Road in Ventnor, a full parking suspension from Lowtherville Road to St Margarets Glade is now in place.

The council says the local network impacts and those in Newport Road and Wroxall will be monitored closely.

The restrictions are as follows:

Ocean View Road, Ventnor between its junction with Gills Cliff Road and its junction with Zig Zag Road, where indicated by no waiting cones on site outside of 32 - 44 Ocean View Road, on the northern side, removing four parking bays.

Newport Road, Ventnor between its junction with Lowerville Road and its junction with St Margarets Glade, where indicated by no waiting cones, on the north eastern side, removing all on street parking.

Clarence Road, Wroxall, between its junction with Mountfield Road and its junction with High Street, where indicated by no waiting cones, on the eastern side outside of 44 and 28 - 30, removing one bay at the southern end and three bays in the middle.

St Johns Road, Wroxall, between its junction with Appuldurcombe Road and its junction with Worsley Drive, where indicated by no waiting cones, on the western side, removing one parking bay at either end the area.