MERCURY NEWS

8 September 2026

Keeping the water flowing:
Mercury replaces vital hydro equipment

The new screen cleaner at Waipapa Hydro Station was installed in winter 2026.
It uses rails to move along the dam and a claw to remove debris.

Vital equipment which ensures Mercury’s hydro stations can continue to generate electricity has been upgraded with modern equivalents.

Mercury is investing $4 million to replace screen cleaner machines at its Waipapa and Whakamaru hydro stations on the Waikato River.

It is part of a wider programme of maintenance works for the Waikato Hydro System, to ensure its longevity to meet the country’s renewable energy demand.

Each hydro dam has water intake screens which work as a filter, preventing debris such as sticks, weeds and rubbish from entering the penstocks which carry water to the hydro stations' turbines.

Joselito Villena, Bede Geoghegan and Cameron Crawford at Waipapa Hydro Station. They have been working on the installation and commissioning of the new screen clear machines.

Screen cleaner machines, stationed at the top of the dams, are then used to remove the debris from the intake screens.

This reduces blockages that can lower power generation, while also improving safety and reducing the need for manual cleaning.

Mercury’s Acting Programme Manager, Generation, Eshan Verma, said the screen cleaners were critical to the hydro stations' operations.

"Keeping the water intakes clear of debris means we can maintain good water pressure down to the turbines, enabling us to generate electricity when it is most needed."

Left: The roof and side panels are fitted to the new screen cleaner at Whakamaru. Top right: The original screen cleaner.
Bottom right: The new unit is set down on the dam.

Eshan said the screen cleaners at the top of Waipapa and Whakamaru hydro dams had reached the end of their useful life.

“We've made improvements to them over the years, but a decision has been made to fully replace those units.”

The screen cleaner at Waipapa was installed during winter 2026 and the one at the Whakamaru was completed in September 2026.

The Waipapa unit can be automated or manually controlled.

Cameron Crawford (Mercury), Greg Komarov (MHM Automation), Kyle Matthews (Wyma Engineering), Jared Taplin (Treescape) and Joselito Villena (Mercury) were part of the team which installed the new screen cleaner unit at Whakamaru.
The unit is set on tracks to allow it to move across the top of the dam.

It uses a claw to reach down and grab debris from in front of the intake screens; it’s then deposited on a conveyer belt and shifted to the side of the dam for removal and disposal.

The new unit at Whakamaru is fully enclosed and must be operated manually to ensure the safety of motorists, walkers, and cyclists using the road across the dam.

The machine sits above the intake bay, and an internal rake descends into the water. When the rake ascends the intake screen, it collects debris and carries it to the surface, where it's tipped onto a chute and then onto a truck for removal.

Eshan said Ātiamuri will be the next hydro station to have its water intake screens and screen cleaner machine upgraded over the next couple of years.

The water intake screens at Whakamaru were also replaced.

MHM Automation supplied the screen cleaner replacements and was responsible for installing the new machines.

MHM incorporates the former Southern Cross Engineering which manufactured and installed some of the earlier equipment on the Waikato Hydro System.