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Work to restore Lake Horowhenua’s environmental health progressing well

Work to restore Lake Horowhenua's environmental health, which has been progressing well since the establishment of the Lake Horowhenua Accord (He Hokioi Rerengatahi) in 2013, will increase in momentum later this year following a High Court decision last week.

The Court’s decision was to dismiss an appeal made by the Hokio Trust, allowing Horizons Regional Council’s weed harvester to undergo a test harvest on the Lake this Spring. 

Horizons natural resources and partnerships group manager Dr Jon Roygard says weed harvesting has been identified by NIWA as the key intervention to reduce the toxic effects of the Lake on aquatic life and recreation. 

“September through to December is the best time of year to harvest weeds so we hope the harvester will be able to go onto the Lake during those optimal conditions,” says Dr Roygard. 

“Before the harvester can enter the lake, a boat ramp will need to be built. Work on the boat ramp is scheduled to get underway as soon as possible.

“We will harvest 50 hectares in this first year, monitor the effects on toxic algal blooms and plan the process for the first full harvest in 2018, according to those results. 

“Horizons are also currently constructing a major sediment trap near where the Arawhata Stream enters the Lake.

“Once completed, later this year, the trap should significantly reduce the amount of sediment and phosphorus entering the Lake from all streams by at least 25 percent,” says Dr Roygard.

Horowhenua Lake Accord chairperson Matt Sword says the Accord’s suite of key interventions aims to address toxic algal blooms, address decades of sedimentation and reduce the amount of nutrients entering the Lake from rural and urban sources, as well as to increase native fish populations by improving habitat and access to and from the Lake.

Other sub-projects already undertaken include the installation of two fish passes, including a large one on the weir at the Lake outlet into the Hokio Stream, four kilometres of stream fencing, the planting of over 7000 plants, the completion of environmental management plans for all 10 dairy farms in the catchment, sediment and erosion control plans for growers covering 80 per cent of the horticultural land in the catchment, and a building of a boat wash facility to reduce the risk of further lake weed species being introduced to and contaminating the Lake.

This work is funded from the $1,270,500 Lake Horowhenua Restoration Fund and includes $540,000 provided from the Ministry for the Environment's Fresh Start for Freshwater Fund, and $730,500 of combined funding from Horizons Regional Council and Horowhenua District Council, as well as in-kind support from industry (Tararua Growers Association and DairyNZ).

Several other projects are also well-underway with an additional $1,092,160 from the Government’s Te Mana o Te Wai Fund, including contributions from the Lake Trust, Horizons Regional Council and Horowhenua District Council. 

Mr Sword, who also chairs the Lake Horowhenua Trust, says the Trust has built a new native plants nursery to support the riparian planting initiatives. This is also a stand-alone enterprise that is creating a revenue stream for the Lake Trust, as well as jobs and training opportunities.

“A flagship initiative is the Glass Eel Repatriation Project where thousands of glass eel are being grown in the Lake Trust’s own aquaculture holding tank facility, before being released back into the Lake,” says Mr Sword.

“These projects are all aimed at improving the condition of the Lake and providing opportunities for the beneficial owners and Muaupoko.

“We are only making a start here. We are not providing all of the answers on day one, but we are now growing engagement and involvement of iwi and the community in Lake restoration projects which is part of a long-term restoration strategy.

“We have made a start, created some momentum and off the back of the recent Waitangi Tribunal report we can get excited about making huge headway on legacy solutions to restore the Lake to full health.”