An ultra-strong log deflection barrier has been installed in the Wainui Te Whara Stream to assist in controlling the effects of future floods.
The deflectors were constructed by Waiotahi Contractors in the stream bed, adjacent to the bottom of Gorge Road, following resource consent approval by the Bay of Plenty Regional Council. Each deflector is embedded to bedrock, six metres below the stream bed, and extends three metres above the surface. The total cost of the installation was $16,570.
The deflectors are intended to capture large, woody debris washed down from the upper catchment during flood events. Previously, any debris would be carried through the stream’s urban reach where it could potentially be trapped by bridge structures, aggravating the flooding risk.
The structure is designed to withstand complete blockage during a flooding event, with a secondary flow path (spillway) created on the right bank to allow flood water to pass around the structure and re-enter the flow downstream. Erosion protection, in the form of rock fill, has been placed to prevent bank scouring along the spillway.
The installation of the deflectors and earlier construction of flood retention dams in the upper Wainui Te Whara Stream catchment are part of a drive to expedite flood protection works and reduce the possibility of flooding in the urban area during extreme weather events. The Whakatāne District Council and Bay of Plenty Regional Council are currently finalising plans for a whole-of-catchment flood protection approach.