Whakatane District

Matata Regeneration Project

Project 3. Awatarariki Stream and Lagoon

Works will involve a upgrading the debris flood channel on the fanhead in conjunction to the construction of silt traps at the head of the lagoon.

Matata LIDAR 1m Contour Lagoon
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The debris detention dam will allow debris floods to pass through the dam and continue into the fan where an improved channel will be required to convey this flow. This channel will be a “balanced cut to fill” type channel constructed along the existing stream channel that may be realigned and straightened to improve (made slightly steeper) the stream gradient and thus reduce the sediment deposition potential in the stream.

This will include measures to limit sediment delivered further downstream in the lagoons during higher flows. These large sediment traps will enable this sediment to be captured and contained for removal in at a later safe period post the event. This may also require the construction of a new state highway bridge and flood channel towards the western lagoon.

Ready access will be required for maintenance and debris removal and management in the Awatarariki Stream and Lagoon.