Waihi Beach Erosion and Accretion Monitoring
The Western Bay of Plenty District Council (WBOPDC) are reviewing the existing coastal inundation areas along the open coastline at Waihī Beach, Bowentown and Pukehina.
A consent to construct a rock revetment wall (sea wall) at Waihi Beach was granted in 2008 but recognising that it was not a long-term solution to coastal hazards, the wall is subject to a resource consent condition requiring the Council to undertake comprehensive investigations over a 25 year period.
Stephen Lun, Reserves and Facilities Projects and Assets Co-Ordinator, WBOPDC, said ‘that part of the consent conditions is to monitor the sand and see if it is accumulating or decreasing as a result of the wall, and get a baseline”.
Recon have completed biannual aerial surveys of the beach over the last 4 years using surveyed control and a commercial-grade UAV with gimbal-stabilised camera. Outputs include a topographic DTM and orthorectified aerial photography following each flight.
Waihi Beach Aerial Survey
Reuben Hansen, Environmental Technical Director, Tonkin Taylor said “as technology evolved, we jumped at the chance to survey the beach using UAV. It gives us a much wider view of what the whole beach is doing! We can see which areas are moving, and it’s great to be able to put up an aerial image”.
The flights had to be completed during Spring low tides, and to comply with safety regulations and privacy (CAA) expectations, Recon scheduled flights during quieter periods. Before each flight, a staff member would walk ahead and notify beachgoers that a drone was about to fly. The flight path covered a stretch of approximately 2 kilometres.
“By using drones, we also get a cross section of the beach, which highlight the seawall footings and low tide mark which fulfils Council’s Consent requirements” said Stephen.
Drones (UAVs) are highly effective for monitoring beach erosion, providing real-time data through high-resolution aerial imagery. They create detailed maps of coastlines and beach features using LiDAR and photogrammetry. Regular flights allow for long-term monitoring and post-storm damage assessments, while also tracking coastal vegetation. Drones offer a cost-effective, flexible alternative to traditional methods, making them essential tools for managing coastal erosion.
“Typically, the data we gather from Recon is used for reports and conceptual designs. The deliverables Recon provide comes as ready to view information, which is really helpful” said Reuben.
Ground surface and contours
Enquiries to Recon can be made through our freephone 0800 732 669 or email info@recon.nz.