Knowledge-based water quality impact for proposed wind farm

Palmerton North City Council (PNCC) entered into a partnership agreement with Might River Power to develop a wind farm within the Turitea Reserve in the northern Tararua Ranges. Nearly two thirds of the proposed turbine sites are located within or adjacent to the Turitea catchment, drinking water source for Palmerston North City. The Minister for the Environment called in the application which had sites for up to 104 turbines in the final layout submitted to the Board of Inquiry.

A detailed Water Quality Impact Assessment was carried out on behalf of PNCC for the hearing to meet their obligations to proactively manage risks to its water supply. The findings of the assessment challenged the construction methodology of the wind farm, and lead to significant changes in the design. These included exclusion of all spoil sites and siltation ponds from the water supply catchment, deletion of all works on steep farmland that drained directly to the Lower Dam where the water supply intake is located, and a balanced view on the risks of not understanding the reservoir dynamics. This process also identified gaps in the reservoir baseline water quality data and implemented a programme to complete it.