Water levels in the Ohinemuri River appear to have peaked and are likely to fall as water moves through the system.
Heavy rainfall that began at 11pm last night caused river levels to rise, resulting in flooding and road closures in the Hauraki and Coromandel areas.
The most intense rainfall occurred from 1am-3am.
Environment Waikato project engineer Jan Hania said 180mm of rain had been recorded between 11pm last night and 8.30am this morning at the Golden Cross rainfall station. The station is located on a hill above Waihi.
“The Ohinemuri River has risen to about a one in five-year flood level and SH2 is closed as a result,” Mr Hania said.
Flows in the river peaked at about 625 cubic metres per second.
“The rivers are going to continue to rise slightly, but it looks like the Ohinemuri River has peaked and is likely to fall as water moves through the system,” Mr Hania said.
“Other streams in the area are also flooding, causing roading problems.”
Surface flooding in the Hauraki Plains area is extensive and SH26 is closed in a number of places.
The Kopu-Hikuai and Hikuwai Settlement Roads are closed.
Mr Hania said more rain was forecast for the next 2-3 hours, subsiding to frequent showers of less intensity over the next day or so.
“What’s interesting about this particular rainfall event is that it’s quite specific to a narrow band between Whitianga and Waihi,” Mr Hania said.
“The Waihou River is rising steadily as the floodwaters in its tributaries flow through, however, as rainfall intensities reduce, the impacts of flooding are not likely to be significant.”
Environment Waikato is working with district council and other agency staff monitoring stopbanks, floodgates and flood pumps and working with local drainage schemes.
“At this stage all flood protection systems, which include stopbanks, pumping stations and telemetry systems are operating effectively,” Mr Hania said.