The town of Grantham during the 2011 Floods.
The town of Grantham during the 2011 Floods.

Nothing could stop flooding in Grantham, says Hydrologist

A HYDROLOGIST has told an inquiry the 2011 Grantham flood was so big it would have inundated the tiny community regardless.

But he said it was the flood's behaviour on January 10, 2011, which had not been experienced before, that affected property and killed 12 people.

Dr John Macintosh told the Grantham Commission of Inquiry on Wednesday there were three identifiable water paths that fateful afternoon.

He said two of the three water paths had not been witnessed before, such was the size of the flood.

"From this time onwards, floodwaters inundated Grantham in a manner that largely caught people by surprise," he said.

"This may well have been on account of not only the speed at which inundation occurred, but also the direction and action of flood flows which had not been previously experienced by eyewitnesses.

"The two additional flows, in conjunction with the initial flow, really exacerbated the situation."

MORE: Hydrologist tells court how railway line worsened 2011 flood

Dr Macintosh's report, which was leaked last week, suggested a century-old rail embankment could have blocked the path of floodwater and funnelled it towards Grantham - water that would otherwise have moved onto the floodplain.

Grantham residents had long held the view a man-made embankment at the Wagners Quarry, located on the outskirts of town, caused floodwater to build up before sending a torrent of water towards the town.

Dr Macintosh's report suggested the quarry may have slightly delayed the arrival of floodwaters in Grantham, but said the creation of the embankment could continue to cause problems in the future.

Commissioner Walter Sofronoff asked all parties earlier this week to agree on a timeline for written and oral submissions, taking into account a final report was due at the end of next month.