River Works

Johnston Civil have constructed two siphons in both the Avon and Heathcote Rivers.

Both of these projects faced the same environmental challenges, and Johnston Civil worked closely with both Downer NZ and Fletcher Construction to construct the necessary silt and spill barriers around the job site, including running all machines on bio oil.

The siphons were constructed with sheet-piled cells, dewatered then the new wastewater pipes installed.

For each halt, the centre was joined by overlapping the ends of the pipe, and then dewatering the centre pit. After this was completed the total siphon was tested then handed over to the respective contractors to complete the works.