South East Water is working with Kent Highways to understand the cause of a ground collapse that occurred on a residential road over the Easter weekend but geotechnical experts believe a burst water main may have been the trigger.
South East Water distribution manager Ann Seach said: “We received reports of customers in Broomshaw Road, Barming, having no water at 8am on Sunday 1 April. When our technician visited the site, they found that part of the road surface had collapsed and a leak on a 150mm water main.
barming russ palmer
Source: Russ Palmer
“Approximately 30 customers were without water for a short time before we were able to alter the flow of water around our network to restore supplies to everyone affected.
“The area has been fenced off to make it safe and we are working with Kent Highways to establish the cause of the problem.”
Peter Brett Associates partner Clive Edmonds believes that a burst in the water main could have triggered the collapse after reviewing his firm’s Natural Cavities Database.
“The geology sequence comprises Cretaceous Hythe Formation overlying Atherfield Clay Formation, the latter which only outcrops in the river valley floor. This sequence is prone to the formation of gulls and fissures.
“The Hythe Formation, due to cambering, tends to have moved laterally towards the valley features over the underlying Atherfield Clay during periglacial conditions associated with past ice ages. As the Hythe Formation opens up along major joints fissures can form that are long and narrow, but deep.
“The surface weathers and forms a soil bridge over the tops of the fissures which remains stable until an inundation event occurs such as a water main burst. The water saturates the soil bridge causing it to fail and be washed down into the fissure which can produce large collapses at the surface. I suspect this is what has happened on this occasion.
“We have been involved with the investigation and stabilisation of a number of these features over the past few years where damage has been caused to property and roads. Nearest similar records of fissures in the PBA database are 1.6km to the north east and south west of Broomshaw Road, but really the whole area has a similar geology and is prone to the problem.”