Residents in a town in Wales have returned home following evacuation 11 days ago after a culvert collapsed in the aftermath of Storm Bert, causing a massive “Sink Hole”. 

The term Sinkhole is used incorrectly at times and the most common cause of a “sinkhole” in our experience is when a service has leaked or perished, which has led to a water leak, which has caused the surrounding ground to wash away. 

The below example was taken from a survey at Redhill Railway Station in 2017 and shows the extents of the ground sink-age and wash associated with such an incident. 

GEOTEC Surveys attended site to complete an urgent Utility Mapping Survey and GPR Survey so that the client could fully understand the scope of the issue and the implication that the broken culvert had had on the site. 

We were able to quickly assist as we hold RSSB RISQS, which allow us to work on the Rail Infrastructure & gain access at short notice. 

The overall survey area is shown below, with sink-age highlighted in purple and unconsolidated ground / voiding associated with the wash from the leak in blue hatching, which indicates the seriousness of this instance. 

The knock on of this being ignored, adjacent to the railway line, could have been catastrophic. Sinkholes can appear small at first and then expand as the problem worsens. The below example is of a hole which appeared in Bognor.