As part of a Wastewater Treatment Works upgrade, a 25m x 50m stormwater retention tank was to be constructed. A formation level of 14m below existing ground level required a novel approach for stabilisation of the temporary batters. Typical solutions such as a secant pile wall or sheet pile wall were not appropriate due to the lack of flexibility to avoid existing infrastructure. The Designer, OGI Groundwater Specialists, proposed their Stable-Earth™ system which comprises of slope reinforcement and erosion control using Platipus Percussion Driven Earth Anchors (PDEA®) together with groundwater management. The design approach was flexible and enabled OGI’s Engineer to adjust the placement and frequency of the Platipus anchors as necessary. The use of the PDEA® System and the OGI Stable-Earth™ system for this large-scale infrastructure project has demonstrated the viability of using cost effective materials to stabilise steep batters for temporary excavation works.