A section of Hagden Lane in West Watford is being dug up, with traffic website One Network stating that the reason is for a "void investigation". Councillor Nigel Bell has told the Watford Observer that he has been informed by workmen that the road should be closed for around a day. Hagden Lane has already been closed three times this year due to the appearance of sinkholes. Hertfordshire County Council has said that the ground in the county is particularly vulnerable to water damage because it is mostly clay and chalk. This means any water escaping from a damaged pipe can easily wash it away, creating a hollow space underground.