Flooding review report
The flooding review report is very impressive in its analysis and recommendations regarding the area downstream of SH5.
However, the terms of reference state that the panel was to address the Ngongotaha catchment, which is noted in the report as covering 7680ha. The area focused on in the report is perhaps 1 per cent of that. The water that flooded the Pioneer subdivision came from the remaining 99 per cent, where the panel notes that the BOPRC does not do any active management.
For anyone who witnessed the actual events on the day, the only reasonable explanation, in our view, was that some major event upstream triggered a violent release of a huge volume of water that burst over the stream edge near Brake Rd. This did not appear to be an ordinary flooding event where the water built up to overtop the stream bank and flow on down the overflow path. Residents observed a sudden huge wave of water coming down the farmland and through to Pioneer Rd. The report notes that the peak of the flood reached Paradise Valley properties two or three hours before it reached Western Rd. That seems to add to the evidence that the water was banked up somewhere between, then suddenly released.
The narrow and meandering Ngongotaha Stream, with its associated exotic trees and weeds, has a huge potential for blockage. We have no confidence that any downstream improvements will prevent a similar event in future. An outcome must be that the BOPRC accepts responsibility to actively manage the stream over its full length.
