Residents in the Mangakino and Whakamaru areas are being advised of two upcoming road closures as part of a work programme to test the Whakamaru Hydro Dam’s diversion gate.
Mercury said the tests form part part of its consent requirements under the NZ Dam Safety Guidelines.
The road is intended to be closed between October 13-17, and then again November 17-21, from 8am-7pm.
Mercury’s Operations Manager – Hydro, James Lord, said the test will ensure the diversion gate is reliable and can perform as expected during high water flows.
It allows water to be redirected to protect people, infrastructure, property and the environment from flood events.
“We need to close the road so we can set up a crane on top of the dam to install 16 steel beams, or stoplogs, in front of the diversion gate.
“This will hold back the water and allow us to remove the gate so we can carry out a full inspection.”
During this process, divers will be in the water and may need to be as deep as 40m to help guide the stoplogs into place, he said. A compression chamber would also be stationed at the top of the dam in case it was needed by the divers.
Lord acknowledged closing the road would be frustrating for people who relied on the route to travel every day, but he hoped the advance notice would give them time to plan their journeys.
“We need to close the road at 8am because it will take us about two hours to set up the equipment each day, and an hour to pack down at the end of the day.
“The work needs to be done during the day, so our team has optimal visibility when manoeuvring the stoplogs into place. Doing the work at night would be dangerous.”
He said Mercury had experience performing maintenance projects at its hydro stations and dams on the Waikato River.
It was important work to make sure the assets were safe for staff and neighbouring communities, he said.
Variable Message Sign (VMS) boards will be in place advising motorists of alternative routes during the road closure period.
