Observations from the design, construction and drone monitoring of a Geotextile sand container (GSC) seawall

The coastline of the Central Coast Council (Council) region located north of Sydney is a highly valued asset as it supports significant economic activity. In mid-2015 following a major storm event, Council identified that coastal erosion was causing an immediate hazard to The Esplanade despite substantial beach scraping. The Esplanade was deemed to be at imminent threat of collapse into the ocean which necessitated the closure of this beachfront road. The Water Research Laboratory (WRL) of UNSW Sydney proposed the design of an interim geotextile sand container (GSC) seawall to mitigate further erosion which is outlined in this paper along with details of its construction. Ongoing monitoring, using UAS (unmanned aerial system or drone) surveying provided a cost-effective monitoring solution and allowed for coastal engineering analysis of sediment transport in the vicinity of the seawall. Based on visual observations and analysis of the data, the seawall combined with beach scraping has thus far been successful at managing the risk of the road being undermined. However, the underlying natural tendency for erosion at this site may continue which could require additional coastal engineering works.