Heat will shut bridge to boaties

UPLIFTING: Boaties wanting to pass under Te Matau a Pohe on hot days above 26C are being urged to travel during cooler parts of the day. PHOTO/ CHRISTINE ALLEN

Summer temperatures are expected to highlight the rise and flaw of Whangarei's prize-winning bascule bridge Te Matau a Pohe.

Whangarei District Council (WDC) has reissued a warning to boaties the bridge may be closed for periods on days with temperatures more than 26C, due to steel bascule expansion which could potentially jam the bridge.

The council shaved off 30mm from the steel lip of the bascule in January, and lifted initial restrictions in March on the proviso it would continue to monitor the way the bridge responded to a range of conditions throughout the year.

But with temperatures rising earlier than anticipated - crossing the 26C mark on Monday with 26.8C - the bridge has expanded sooner than council expected, WDC roading manager Jeff Devine said.

"The restriction is a precaution we are taking to make sure no damage occurs and we will continue investigating the expansion.

"Every new year we are continuing to learn more about how the bridge behaves. We have to learn these things first hand because there are so few of these bridges in the world, and this is the only one here, experiencing the circumstances that occur in summer.

"We expect to continue finding out new things as the years roll by."

He's advising boaties planning to leave or enter the upper harbour thought the bridge to keep an eye on the expected high for the day.

"If it is likely to hit 26C or more, to plan to leave in the cooler hours of the morning or evening."

Whangarei has an average of 18 days a year with temperatures above 26C, MetService meteorologist Georgina Griffiths said.

In the 2013 summer there were 19 days with temperatures above 26C.

Mr Devine added: "Every season is different, and every year is different, so we need the bridge to go through several cycles of seasons before we know exactly what to expect in every circumstance." -Bridge control can be contacted on VHF Channel 64, or telephone 438 7621 or 021 401752.