River work cuts flood risk to historic sites

Work to improve flow in the lower reaches of the Kerikeri River will mean the historic Stone Store and Kemp House are less at risk of future floods, the Northland Regional Council says.

A one-lane bridge at Kerikeri Basin blamed for regular floods threatening two of New Zealand's oldest buildings was removed in 2008, but work now under way should further reduce the risk of damaging floods such as those of 2007.

Regional council rivers programme manager Joseph Camuso said 600 cubic metres of material had been removed last month from a boulder bank which had formed in the riverbed upstream from the old bridge.

A temporary "haul road", allowing trucks and machinery to access the boulder bank, was built using geotechnical cloth and a layer of aggregate to protect the remains of a historic fence believed to lie beneath the soil. The haul road had since been removed. Some material had been re-used on site for scour protection while the rest was trucked to a nearby property.

The next step would be to reduce the height of an abutment left behind when the bridge was demolished, involving removing about 180cu m of material.

That stage is on hold until Northland staff from the Historic Places Trust complete an archaeological assessment of the abutment. The work will tie in with a Department of Conservation project to improve a nearby carpark and remove the last remnants of road leading to the old bridge.

The project will cost about $25,000 and be paid for via a targeted rate, the Kerikeri-Waipapa River Maintenance Rate, approved by the regional council's Kerikeri River Liaison Committee.