As the massive clean-up continues in Wairoa, residents are starting to question whether the flood that inundated hundreds of homes and businesses was caused by Genesis Energy, not Cyclone Gabrielle.
When the Gisborne Herald visited Wairoa’s flood-stricken North Clyde area yesterday, several residents said they were concerned the power company might have made a poorly-timed decision to open a floodgate at its Lake Waikaremoana dam, creating the sudden surge of water that spilled over the banks of the Wairoa River.
Genesis Energy says it was not responsible for the flooding and that hydrology data showed the excess river flow came from tributary streams beneath its lowest power station.
Michelle McIlroy was among those who expressed concern about the possible floodgate scenario, saying residents would be asking questions of Genesis.
She wondered if the dam had been at capacity and if there had been a need to let water out, why it wasn’t done ahead of the cyclone.
“It could’ve been at capacity and they would’ve needed to let the water out, but they should’ve warned us because they could have killed people — if it was that.”
People were constantly being told to prepare for the cyclone. If Genesis knew there was going to be 200 to 400 millilitres of rain, it should have been releasing water ahead of it, she said.
But Genesis chief operations officer Rebecca Larking said, “our resource consents require us to manage the level of Lake Waikaremoana, which in turn helps manage the flow of the Waikaretaheke River, which flows into the Wairoa River. The discharge through the Waikaremoana Power Scheme was less than 1 per cent of the total flow at the Wairoa township during Cyclone Gabrielle. A lot of the water that enters the Wairoa River flows in through tributaries below Genesis’ control points on the Waikaremoana Power Scheme.
“During the cyclone, Genesis released between 35 to 40 cubic metres of water per second from Lake Waikaremoana as required by our consents.
“By the time the Wairoa River entered Wairoa township, it had peaked in excess of 6500m3 per second, (according to the Hawke’s Bay Regional Council river flow data), showing how much water entered the river further downstream, outside of Genesis’ points of control.”
Read More: Cyclone Gabrielle: Dispute over Genesis Energy’s role in Wairoa flooding