Flood defences protecting The Valley in New Plymouth have been strengthened by Taranaki Regional Council following the major weather event which hit the region in early July.
AA Contracting's Will Adlam and TRC Rivers Officer Daniel Lumb check out the upgrades to the Waiwhakaiho River flood defences.
The $350,000 work has been completed after the Waiwhakaiho River was inundated on 3 July and a 45-metre stretch of the berm adjacent to the stopbank near Mitre 10 Mega was washed away.
The project got under way before a second weather event hit the region on 11 July and has included adding 1,800 tonnes of rock and bank contouring.
Council Director-Operations Dan Harrison said the area had suffered severe erosion when river flows rose dramatically and the new rocks are an additional safeguard for homes and businesses in the popular retail and business area.
“There was a huge amount of rainfall and waterways right across Taranaki rose with some having unusually high river flow levels so it wasn't all that surprising to have some erosion on banks and berms,” says Mr Harrison.
“When the waters receded, it was clear this area was vulnerable to further erosion so we got work started and we’re delighted to have the project completed in about a month. We’re confident this has improved flood protection for homes and businesses in the area.”
On 3 July, there was a maximum river flow of 417m³/sec recorded in the Waiwhakaiho River at Egmont Village while the Waitara River was 1,275m³/sec.
The gauge near the upgraded site at the lower Waiwhakaiho River recorded around 420m³/sec before it was damaged by the floodwaters. Work in the area will also include adding some rocks near to the monitoring site to protect the equipment during future high river flows.
Mr Harrison said funds for the $350,000 works have come from the North Taranaki River Control Scheme reserve and $50,000 is also being used from this reserve to fund repairs to the flood protections at the Hangatahua/Stony River.
“We’ll be looking to do some repair work on the Hangatahua in the summer months as there was some damage to a rock bank during the high river flows. We’ll be replacing about 150 tonnes of rock which shows the ferocity of the river on 3 and 4 July,” added Mr Harrison.
More than 1,800 tonnes of rock have been added as part of the work upgrading flood defences near to The Valley in New Plymouth.