The number of flood-prone homes known to the council has doubled since Monday.
On Monday the Christchurch City Council released flooding ''vulnerability categories'' which identified:
- 56 homes had flooded above floor levels twice or more.
- 451 homes had suffered flooding below floor level more than twice.
- 487 homes had access compromised by flooding more than twice.
However the head of the council flooding taskforce today admitted the data was already "significantly" out of date.
Land drainage operations manager Mike Gillooly told the Stormwater 2014 conference that more homeowners had contacted the council to say "hey, you left me out".
Did the council miss you off its map of flood-prone properties? Email email@example.com to tell us your story.
Not only had the flood-prone numbers doubled, it was doubling "in areas where I didn't realise we had flooding".
"One of the key things about flooding is not everyone rings up and says I'm flooded you better come and have a look. They deal with it themselves,'' said Gillooly.
When assessing the ''vulnerability categories'', the taskforce visited areas which had reported flooding, he said.
''We couldn't look everywhere so we had to look at certain places where we knew flooding was most prevalent."
In particular, these were the places which flooded in March, April and May this year, but also in August 2012 and June 2013.
''We've had a lot of flooding but we have also had a lot of rain,'' he said.
Gillooly said the situation was unacceptable in a ''first-world'' country.
''Being flooded once is an insult. But it is an absolute travesty to be flooded more than once in a first-world country,'' he said.
He told the conference that ''complacency'' had played a part in the flooding.
'' . . .one of the things about Christchurch in the past 10 or 15 years, is that land drainage and surface water has been the poor orphan to the other two waters - water supply and waste water - and we led ourselves down a path of complacent thinking where everything would be OK when clearly it is not,'' Gillooly said.
Solutions were needed quickly, with reports of increased respiratory problems and mental illness, he told the conference.
- The Press
Should residents do more to help maintain the city's parks and reserves?Related story: Christchurch citizens to mow parks?