DMK Contracting was engaged by Fulton Hogan to undertake specialist wastewater infrastructure works as part of the Whanganui Prison Sewer Project Upgrade.

Across the 9 km sewer main project, DMK was responsible for the installation of scour valve chambers, air valve chambers and flushing points. Chamber installations ranged from approximately 1.8 m to 5.5 m deep, requiring careful planning and safe excavation practices throughout the eight-month programme.

Due to the depth of the installations, trench shields were used for the majority of the chamber works to provide safe excavation support. Shoring was also required at several locations where groundwater and ground conditions presented additional challenges.

Dewatering was carried out at each installation using bird’s nest systems to manage groundwater within the trenches and maintain suitable working conditions. DMK’s team also completed all electrofusion (EF) coupler welds associated with each chamber installation.

The project was delivered by DMK over an eight-month period as part of the wider 9 km sewer main upgrade.