The Waihi Beach shoreline has been the focus of erosion control since the 1950’s. During this time ad-hoc coastal erosion protection structures such as steel and timber retaining walls, gabion baskets, tipped rock and sand containers have been employed. Subsequent storm systems had a twofold effect on the coastal area, with both stormwater flow and the action of the sea taking a toll on creek outflows. The Surf Club is a public area and a popular stop-off for locals and visitors so providing a user-friendly solution was deemed important.
Whilst Tonkin & Taylor provided the design, Geofabrics staff assisted with on-site training. Tips and tricks gained over the years of experience using the product were shared with the contractor to ensure works proceeded safely and efficiently. This enabled the sensitive beach area to be returned to public use in a timely manner.
The Fulton Hogan crew were quick to adopt the training tips communicated. Prefilling a batch of Elcorock containers allowed for rapid deployment once the foundation was cut and stream flow/tidal ebbs were optimum. The use of on-site sand expedited the process, which proved useful with limited weather windows and opportunities to construct. Construction of the Elcorock structure commenced at a design level deep enough to avoid future scour. Further mitigation was employed using Geofabric’s Elcorock “Self Healing Toe” sand containers placed at the founding level. Should scour occur below the design level, the toe of the structure rotates to fill the void created.
A storm just two months after install left the seaside town of Waihi Beach flooded. Big seas, wind, and rain all pummelled the coast with 100 mm of rain recorded in nearby rain gauges. This is the true test of the product and it was left unscathed.
The Elcorock functioned as designed when exposed to the elements and has a proven track record of longevity. The end result utilising soft engineering has enhanced the landscape, compared to a rocky rip-rap alternative and maintained the areas useability by the local community and visitors.