Bournemouth Borough Council has yet to establish the full scale of damage caused by flash floods last week.
Road surfacing badly damaged
The floods overloaded highway drains, damaged road surfaces and washed sand and silt from cliff tops.
Road surfaces were severely broken up by high water pressure in council-owned drains beneath them at two central locations.
But the council is still receiving reports from residents of other, smaller areas of damaged road surfacing, and repair work may not begin for two weeks.
Bournemouth Borough Council planning and transport services director Mike Holmes said information about “a few square metres here and there” was still emerging.
He said full inspection and repair of roads would not start until the scale of damage was confirmed. This could take two weeks. Holmes said it was standard practice for the council to spend time collecting this information after a flooding incident. “What we are doing at the moment is collecting data about what has happened,” he said.
The road surfaces are believed to have been damaged after unprecedented rainfall on 18 August, when surface water inundated highway drainage sewers beyond their capacity and the resulting extreme water pressure caused the pipes to fail. High water pressure in the drains also forced manhole covers out of place in many streets.
The two biggest road damage incidents were at Gervis Place − where flood waters also damaged a gas main, which was quickly repaired − and on Exeter Road, a major intersection for local bus routes.
Holmes described the damage at these locations as “spectacular”, but it is not yet known exactly what has happened because the damaged pipes have not yet been excavated. “We haven’t dug it up, it was a matter of securing the area [as a priority].”
The seafront was a priority because the flood waters loosened sand and silt down cliff sides. A geotechnical engineer from consultant Mouchel − which has an ongoing planning and transport contract with the council − inspected the cliffs on 18 and 19 August and declared them safe.
A Wessex Water spokesman said there were no operational failures of its sewers or pumping stations. He said some sewer flooding had occurred, but most of the floods were caused by surface water.