A flurry of excitement ran around the region when heavy machinery was seen working on the riverbank where, in 2019, the first moa prints found in the South Island were discovered.
However, NZ Transport Agency Waka Kotahi Central Otago maintenance contract manager Peter Standring said the work was to protect the Kyeburn bridge abutments.
The river would be "retrained" to spread the pressure of the river’s flows more evenly across the span of the riverbed, reducing the river’s speed and subsequent scouring of the true left river bank, he said.
"With all the river’s flow channelled towards that true left, we are also seeing increased scour [undermining] of the bridge abutment [which connects the bridge to the land/highway] in high water flows."
Moving the riverbed shingle around upstream and downstream of the bridge would encourage that central pathway. The work should be completed by the end of this month.
About 880 vehicles crossed the Kyeburn bridge each day.
The $150,000 funding for the work came from the emergency response activity class — part of the National Land Transport Programme.
Retraining the river was a long-term solution to protecting the bridge, he said.
The Central Otago District Council (CODC) went to the NZTA last year looking for help to fund $20 million of bridge replacements in the next 10 years. The council’s budget for bridge maintenance and renewals is $660,000 a year.
At the time, council infrastructure manager Quinton Penniall said a specialist bridge engineer, in collaboration with a council contractor, had quantified the bridge maintenance backlog.
There was an estimated $1.5 million of maintenance and $2.5m of renewal required to ensure the region’s bridges reached the end of their useful life.
It was proposed priority be given to bridges deemed strategically the most important, and carried the highest risk to the network, he said.
Kyeburn captured national attention when seven moa footprints were discovered in the riverbed close to the bridge by Ranfurly man Michael Johnston.
They were the first moa prints found in the South Island, although bones and fossilised droppings had been found. The footprints were removed shortly after their discovery by staff from Otago Museum and University of Otago and taken to the museum.
In November last year, a team of research scientists from the University of Otago geology department, Tūhura Otago Museum, Victoria University of Wellington, the Australian Nuclear Science and Technology Organisation and Aukaha Consultancy revealed the footprints were 3.6 million years old and from the Emeidae family.
A 3D photogrammetry model of the fossil site revealed there was also possibly a member of the Dinornis genus, which included the largest-known species of moa — the South Island giant.
Fully grown females are thought to have been up to 250kg. Although the Kyeburn precursor was lighter, it was still impressive at an estimated weight of 158kg.
