Last Tuesday 18 August, treatment plant operators were alerted to a possible overflow incident at the Martinborough Wastewater Treatment Plant, potentially due to a valve operation failure. Operators made a physical inspection of the overflow point to the river, as well as along the river downstream.
No evidence of discharge to the river was found. A comprehensive water quality sampling programme was also initiated in the area, and did not detect any contamination. We are undertaking a full incident investigation which we will be made public once completed. The Martinborough Wastewater Treatment Plant is now operating normally.
This incident occurred in the context of historical challenges with the plant’s design, which we are working through with a programme of system improvements. Wellington Water is meeting next week with South Wairarapa District Council to update Council on progress and the plan for further improvements.