The Waiau River system appears to be in good shape following repairs to the sluice gates at the Eastland Group-owned Waihi dam, near Wairoa.
The 5MW hydroelectricity station was out of operation from late last year until 23 March, following damage to the sluice gates caused by extreme weather in September 2015. The damage meant one of the gates could not be fully closed, resulting in silt being released into the Waiau River system.
Eastland Group chief executive, Matt Todd, says the company worked urgently to make repairs to the gates.
“As permitted by Hawke’s Bay Regional Council we worked seven days a week in extremely challenging conditions to repair the gates and get the dam operational again.”
He said claims that higher-than-usual sediment levels had caused long-term harm to the river system appeared to be overstated.
“An ecologist visited the rivers last week to take water samples and told me it was highly likely that ecological recovery is occurring and can be shown in the Waiau even quite close to the Waihi. The observations of mullet, trout, eels observed locally by others and the small fish seen last week support this.
“These are normally high sediment river systems and, as soon as there’s a reasonable rainfall, any residual sediment moves through quite quickly. It appears the river life is used to changing sediment levels and is able to cope very well.”
Mr Todd said Eastland Group would continue to monitor the rivers and also planned to fly rivers regularly with a drone “so we can check the visual appearance of the rivers”.
He said Eastland Group was still waiting on the results of the HBRC investigation into the damaged sluice gates at the dam, and had not yet received any substantive claims for compensation.
The Waihi dam is part of the Waihi hydroelectricity scheme, generating enough power for 1600 homes, and has been owned by Eastland Group for 17 years. It was built by Wairoa Electric Power Board in 1986.