A young woman swimming in the river immediately downstream from the 78-MW Aratiatia hydroelectric facility was swept away and killed when the dam’s floodgates were opened Feb. 6.
Warning signs are in place to alert the public about discharges through the gates, which occur four times a day in the summer so tourists can watch the downstream rapids from a viewing platform. In addition, the section of the river near the dam is fenced off to prevent people from swimming and sirens sound before the gates are opened.
It does not appear that discharges through the gates have any relationship to operation of the hydropower plant.
News agencies are reporting that Mercury, owner of the facility, is reviewing its safety procedures but that “it appeared not much more could have been done to prevent the death.” Mercury Chief Executive Officer Fraser Whineray confirmed the sirens were working at the time of the incident, according to the NZ Herald.
Regardless, Radio NZ reports Mercury has suspended opening of the dam.
The 21-year-old woman was one of a group of four swimmers who were caught in the discharge; the others made it to the bank of the river.
Mercury (which brings together Mighty River Power and Mercury Energy) owns nine hydro plants on the Waikato River, including Aratiatia, which impounds Lake Taupo and began operating in 1964.