Monitoring equipment coming for Leeson Road after Bonchurch landslide

The Isle of Wight Council has responded to a newly formed residents' group, led by Ventnor resident David Groocock, to explain why the promised additional monitoring equipment is yet to materialise.

Questions had been raised as to why the specialist monitoring equipment had not yet been installed, more than three months after the December 10 landslide.

Residents were told at a public meeting on February 29 that the additional equipment would gather the data required to gauge when and if it will be safe to open Leeson Road again.

Bonchurch landslide. Picture by IW Microlights (Image: IW Microlights)

The urgency for information, the group say, is the impact the road closure is having on Ventnor and the surrounding communities of Wroxall, Whitwell, St Lawrence, and Shanklin. 

Mr Groocock asked the council: "This lack of urgency, coupled with poor communication, is causing distress within the community. In view of this, we would like to understand the reason for the delay."  

• Read more: Ventnor councillor says leaving the roads to nature is not an option

The response from the council stated: "We have apologised for the length of time this process takes, and appreciate that it must feel that there are delays and lack of urgency, however I can say that this is not the case."

Here are the main points from the Isle of Wight Council's response

The monitoring equipment and locations is extensive.

Given the catastrophic nature of the failure in Bonchurch, the area has been deemed unstable and geological behaviour of deep layers has to be established to remove the doubt and inherent risk.

To establish the monitoring required, this has initially taken extensive study by specialist consultants, and these investigations continue in parallel to the ordering, delivery and installation of monitoring by the specialist survey company Socotec.

It has been agreed to add specialist global navigation satellite system (GNSS)  equipment to the plan, to provide remote monitoring.

Monitoring work has always been ongoing, with regular engineering visits and also weekly level surveys along the length of the road. This level survey is being looked at closely as a continued indicator of any movement in the vertical plane. While not extensive, there have been some vertical movements along the road section, particularly those areas close to the rear scarp.

Permissions have to be sought for the siting of new equipment as it is in some cases affixed to properties or in areas that have requirements from National Trust or Natural England to comply with. 

The failure of the Bonchurch area has been a different failure to those experienced in other areas of Ventnor.

Monitoring will take a while and depending on what it shows, may need to continue.

Usable boreholes for the recovery of greensand and gault clay samples need to be drilled in more suitable conditions when the substrate and deep layers have dried. February and March have continued to see very high levels of rainfall, triggering some higher target levels that indicate warnings regarding the likely continued activation of substrates.