As a result of extreme wet weather that impacted the Northern Rivers of NSW in Feburary 2022, a significant landslide occurred adjacent to the buried DN600 St Helena Trunk watermain. With concerns of landslip regression resulting in damage to the watermain and affecting the towns water from Byron to Lismore, LRC Geotechnical were engaged to complete geotechnical investigations analysis and design to inform ‘for construction’ design of landslip remediation. Following investigation and detailed analysis, a permanent remediation design, comprising a soil nail wall with shotcrete facing in combination with extensive drainage was preferred. The remediation acted to stabilise the hillside and protect the existing infrastructure in the long term. The soil nail wall was successfully completed in May 2025. The geotechnical services provided for the project include: Preliminary and supplementary geotechnical investigation programme with borehole advanced to 20m in areas as well geotechnical mapping of existing slip scarps. Laboratory analysis of encountered soil and rock to ascertain geotechnical parameters for design. Finite element analysis to assess the stability of the hillside and provide recommendations of soil nail dimensions, wall extent and thickness for design documentation. Preparation of construction documentation including project specifications, construction staging and site access. Construction phase support including RFI and design revision. Geotechnical supervision and certification of soil nail wall.