A trial planting by Contact Energy at the water’s edge of Lake Dunstan's Kawarau Arm has faced early setbacks, with high lake levels and wave action making it difficult for some plants to take hold.

Whitestone Contracting installed the first plants in late December, fencing the area to protect them from pests.

The trial - part of a wider project targeting the foreshore of the lake near Cromwell's heritage precinct - will test which species and planting methods can survive in the hydro lake’s fluctuating conditions.

“Recent high lake levels, variable ground conditions, and wash from boats and jet skis have made establishment challenging,” Contract Energy said in its latest update on the project.

"Some plants have lifted before their roots have taken hold.”

Contact Energy said staff are checking the site regularly and replacing dislodged plants, and EcoWool mats and biodegradable pins are also now being trialled and are proving effective in keeping semi-submerged plants in place.

Some plants have floated away rather than taking root. Image: The Central App

The update also addressed concerns about raupō (bullrush) that appeared limp after transplanting.

“The stalks you see above the water are last season’s growth, and they naturally decline,” it said.

“The important part of the plant is the strong underground rhizome...These locally sourced rhizomes are healthy and will send up new shoots once the plants settle into their new location.”

Weekly monitoring and clearing of debris and algae are planned for the next five weeks to support plant establishment.

The trial is part of a broader plan by Clyde Dam operator Contact Energy to revamp a silted section of the Kawarau Arm waterfront – an obligation of long-running consents related to the dam’s operation.

Further resource consents granted in December allow for a 320-metre boardwalk, an upgraded jetty, and a flat-grassed area, in addition to native planting.

The plan, developed in consultation with local residents and lake users, addresses sediment accumulation along the lake edge that has affected beaches and boat ramps in recent years.

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