At its meeting on Wednesday 28 August, the Waitakere Ranges Local Board will consider a report regarding trigger points for the Wekatahi and Marawhara Streams (Item 19 of the attachment below).
Historically the streams either join or run in parallel down North Piha beach. A decade or so ago, the joining of the streams resulted in their moving southwards and threatening to undercut the road. In 2004, bulldozers were used to separate the streams and replant dunes in the hope this would keep them separate.
For a long time they did, then the streams rejoined and started moving southwards again. In 2012 the Auckland Council again bulldozed them separate. Subsequently, they have rejoined, but this is some distance down the beach, a substantial dune having between created between the two streams at the landward end.
The Board has been considering where the trigger points should be for further situations.
The Council’s Coastal Experts have come up with three trigger points they state are reasonable for when to step in, these trigger points being design to protect the road and the buffer area of the foredunes. All three trigger points will need to be reached before the Council will act. The Board is being asked to endorse these.