Number 8 solution to flood rescue

By ROSALEEN MacBRAYNE

Environment Bay of Plenty engineers Bruce Crabbe and Tony Dunlop resorted to old-fashioned Kiwi ingenuity yesterday to control flood waters on the Rangitaiki Plains.

They dropped a modified shipping container into a gap in a cut above the Thornton bridge, which crosses the coastal road between Whakatane and Matata.

The cut has been deepened to allow more water to flow through and, because of its depth, the gap needs to be blocked off when river levels rise with the incoming tide.

How to put a finger in the dyke when necessary and then remove the stopper again? That is where the enterprising engineers came in.

At high tide the container doors will be closed and opened again when the water level falls.

"They have come up with a most ingenious method - a first in the world," said regional council spokesman Bruce Fraser proudly. "There is simply so much water on the plains."

The devastation wrought by heavy rain in the Eastern Bay of Plenty has been described as a one-in-100-years event.

Thousands of hectares are still inundated and, although levels are falling slowly, it could be days before the water drains away.

Even without the 100m-wide breach in the Rangitaiki's stopbank 1.5km upstream from Edgecumbe - which is allowing enormous quantities of river water to pour into the saturated plains - there would have been a huge flood anyway, because of the deluge of rain, Mr Fraser says.

Whakatane has suffered the consequences of the Whakatane River breaking its banks, and small communities, dairy farmers and kiwifruit orchardists have taken the brunt of the Rangitaiki's volume, increased by spill from the swollen Matahina Dam.

Once a giant swamp, the low-lying plains have been drained over the decades, allowing much of the original wetland to be used for farming.

Environment BOP administers more than 30 artificial drainage systems, including canals, on behalf of Rangitaiki Plains land users.

There are 40 different pumping stations but several 2.5m high sheds containing electric pumps are under water this week. The rest have been working around the clock moving water from the plains into the Whakatane and Rangitaiki Rivers.

Much of the water pushing through the 100m-wide breach in the Rangitaiki stopbank was yesterday returning to the river through several controlled cuts further downstream.

The regional council is now building a road to allow access to the breach so it can be closed.

About a quarter of the Rangitaiki's flow is still pushing through the breached stopbank and has formed a new "river" running parallel to the main river.