A sinkhole was reported late last Tuesday morning (January 14) on Gratwicke Road, Worthing.
"Our team promptly visited the site to ensure public safety,” a West Sussex County Council spokesperson said.
"The affected area has been cordoned off for safety, however as it is a one-way street, we have been able to keep the road open.
“At this stage, it is too early to determine the cause of the sinkhole. However during the site visit, our highways operative was informed of an issue with the water supply by local residents.
"As part of our standard procedure, we have alerted Southern Water to investigate whether the sinkhole may be linked to the water supply problem.
“We are awaiting confirmation from Southern Water following their checks. Once we have more information, we will assess the next steps and take appropriate action.”
A week later, the county council said the situation with the sinkhole ‘remains unchanged at this time’, adding: “We’ve been in regular contact with Southern Water since the issue arose and are awaiting their findings to determine any next steps.”
Southern Water confirmed its teams are ‘investigating reports of a collapsed sewer’ that ‘has resulted in a sinkhole’.
A spokesman added: “We are planning to start work this week to carry out repairs. We’re sorry for any disruption this will cause customers, businesses and commuters.”
The water company will make West Sussex County Council aware of any works it intends to carry out. It is understood that the sinkhole is not related to any water supply problems and the primary cause is a sewer collapse.
According to the British Geological Society (BGS), there are several different types of sinkhole (also known as dolines) – ‘caused by different processes, including dissolution, collapse and erosion’.
The BGS explained: “Some sinkholes result from the surface dissolution of soluble rock. For example, limestone rocks dissolve when attacked by rainfall or groundwater that is acidic.
"Collapse dolines occur as consequence of the gradual collapse of a cave passage at depth. The collapse may gradually propagate up through the overlying strata to cause subsidence at the surface (a ‘collapse sinkhole’).
"Sinkholes can also form as a result of both dissolution and subsequent collapse. Where a thin covering of loose, superficial material (such as sand, clay or soil) covers the soluble rocks beneath, the soil can be washed into solutionally widened fissures or cavities.”

1. Worthing sinkhole
A large sinkhole appeared on Gratwicke Road in Worthing. Photo: Eddie Mitchell

2. Worthing sinkhole
A large sinkhole appeared on Gratwicke Road in Worthing. Photo: Eddie Mitchell

3. Worthing sinkhole
A large sinkhole appeared on Gratwicke Road in Worthing. Photo: Eddie Mitchell

4. Worthing sinkhole
A large sinkhole appeared on Gratwicke Road in Worthing. Photo: Eddie Mitchell