The Ngaruroro was second worse off, with about 4km weakened, the Hawke's Bay Regional Council says. Photo: Supplied / Dawson Bliss
New figures show 16km of stopbank on either side of one of Hawke's Bay's main rivers have been weakened by Cyclone Gabrielle.
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The damage on the Tūtaekurī River is the most extensive of the nine rivers and water courses assessed.
A Hawke's Bay Regional Council update from earlier this month showed 25km in total weakened, and about 5.3km breached.
Photo: Supplied / Hawke's Bay Regional Council
The Ngaruroro was second worse off, with about 4km weakened.
But it has only half a kilometre breached, versus about 3km of the Tūtaekurī, which flows along the edge of Napier's Taradale suburb.
Emergency work has been completed on flood protection and now repairs costing tens of millions of dollars have begun.
Detailed drone inspections have been carried out to plan for urgent repairs at critical areas.
The latest condition of the stopbanks on the Tūtaekurī and Ngaruroro Rivers between Hastings and Napier, and Waipawa River, as of 8 March. Red shows a breach, yellow means weakened, and green signals OK. Photo: Supplied / Hawke's Bay Regional Council
The council said it had high confidence in the breach assessment, and moderate confidence in the weakened assessment, arrived at using drone photos and videos as well as other checking.
"We are working as fast as we can to repair stopbanks," it said in its update.
It also showed rainfall from 6am Monday to midnight Tuesday during the cyclone was double what was predicted at certain monitoring spots on the Esk River (at Glengarry, the highest, at 258mm in total), and almost double that predicted in the next three wettest spots, Tukituki (at Waipoapoa, 216mm), Wairoa (at Fairview, 213mm), and the Ngaruroro and Tūtaekurī rivers (186mm).