Leeson Road to re-open Sunday

Posted on: November 28, 2024 at 5:12 pm

Leeson Road, between Shanklin and Ventnor, will re-open on Sunday morning (1 December).

The road will be fully opened to all two-way traffic and pedestrians from that date.

This planned re-opening follows the completion of three boreholes and the installation of monitoring equipment. The deepest of the boreholes reaches 130 metres.

The monitoring equipment in the boreholes and on the surface of Leeson Road will measure ground movement and water pressure to inform Island Roads and the council of changes that may indicate land movement.

The equipment will continuously monitor the area and in addition there will be weekly site inspections and regular reviews of automated data.

Using the data, Island Roads and the council have agreed on an emergency response plan that will use triggers to indicate low, medium, or high-risk scenarios.

Depending on the risk level, appropriate actions will be taken to ensure public safety. If the road needs to be closed information on the closure will be published on the council’s social media channels and sent to local press as quickly as possible.

Councillor Phil Jordan, council leader and Cabinet member for highways and infrastructure, said: “We are extremely pleased that the road will be reopened ahead of the Christmas period, and I would like to thank residents and the business community for their support and patience during this work.

“I know how difficult this has been for the community generally and work has not been without problems to overcome but I am extremely pleased with the outcome.

“The monitoring equipment installed, plus the information we have taken from the boreholes themselves, have confirmed our understanding of the underlying geology and also allowed systems to be put in place that will allow us to monitor the area in detail to provide early warning of any increase in the risks of a future landslip.”

Further information

What equipment has been installed:

Automated Monitoring Systems:

• Tiltmeters: 22 tiltmeters have been installed in April/May 2024 to detect surface tilt in two directions. These devices provide early warnings of ground movement.
• GNSS Units: Three GNSS installed in the summer units monitor ground displacement in three dimensions, offering precise data on land movement.
• Extensometers: Installed in April/May 2024 to measure the widening of tension cracks, these instruments help detect early signs of ground instability.
• Vibrating Wire Piezometers (VWPs): Installed during the November borehole works are five VWPs that measure groundwater pressure at various depths, crucial for understanding subsurface water levels.
• Automated In-Place Inclinometers: Also installed in the November borehole works these will measure ground movement at specific depths within boreholes.
• A second additional weather station will bring further robustness to the monitoring and provide weather data immediately adjacent to the landslip.

Manual Monitoring Systems include:

• Inclinometers: Borehole inclinometers are manually monitored monthly to track deep-seated ground movements.
• Survey Points: 84 survey markers along Leeson Road are surveyed monthly using RTK GNSS units to detect changes in elevation and position.

Rainfall Monitoring: Ventnor Park Weather Station: This station continuously records rainfall data, which is vital for assessing the impact of precipitation on landslide activity.

Drone Surveys: Photogrammetry and LiDAR  surveys produce high-resolution digital terrain models and orthophotographs, allowing for detailed monitoring of ground changes over time.

Monitoring Workflow and Action Plan:

Data from the equipment, added to that already being retrieved from existing equipment will provide the information needed to manage an early warning process that will allow the road to be re-opened and operated safely in parallel to the landslip risk.