Heathcote River Breaks Banks, Surface Flooding
Heathcote River Breaks Banks, Surface Flooding Across Chch
Christchurch City Council’s phone lines were running hot today as people called to report surface flooding across much of the city.
By 2pm Council staff had fielded about 2800 calls, about 100 more an hour than is normal for a Tuesday. Most storm-related calls have been about surface flooding. There were also reports about branches falling from trees. No major roads have had to be closed and by late afternoon most floodwater had drained away.
After a third day of rain and gusty winds, the Heathcote River broke out of its channel at about 9.30am at the south end of Beckenham Loop and near Beckenham School on Eastern Terrace. Low tide was at about midday which helped the river’s ability to carry water to the estuary. And although the rainfall was becoming less intense by late morning, streets further down the river were flooded throughout the day, with reports of water in garages but no calls about it in homes. Council staff said water was up to half a metre deep in some places.
By about 3pm, however, Fifield and Eastern terraces on the north bank of the river and Riverlaw and Palatine terraces on the south side were again mostly clear of water. It will take Council staff and contractors several days to clean up the rubbish and debris left by the flood. Some erosion points along the river will also need work.
High water tonight is at around 6pm and this could again push the river up so Council staff will continue to monitor the Heathcote’s level into the evening.
The Port Hills above Cashmere and Huntsbury had the most rain. Drainage systems in those valleys all feed into the Heathcote. As with the October 2000 storm, the highest rainfall over the last three days has been recorded at the Council’s rain gauge at the head of Bowenvale Valley. At midday, the valley gauge was showing almost 140mm (5.5 inches) of rainfall since Saturday. In the October 2000 storm that gauge gathered about 190mm (7.5 inches). At least half the rainfall has fallen in the last day. The heaviest period was in the hour from 8am today, when the Bowenvale Valley gauge gathered about 9.5mm.
There was surface flooding over many other roads throughout the city, including at the big roundabout leading into the Northcote subdivision west of Main North Road and at Glasnevin Drive, near Tulett Park in Bishopdale.