WA – Kununurra Diversion Dam Remedial Works

Works have been underway at the Kununurra Diversion Dam since May 2019. The dam is located in Kununurra in the East Kimberley Region of Western Australia. The scope of the works has been to strengthen the rockfill embankments in areas where these embankments were not founded on rock. These works also included components to reduce foundation piping potential. Works at the site consisted of:

• Right Abutment: Ground improvement (stone columns) and weighting zone installations (complete with filter zones including a sand foundation curtain)
• Left Abutment: Foundation Drainage trench and weighting zone installations (complete with filter zones)

The works at the site have also included a comprehensive instrumentation upgrade, site access improvements and significant public access improvements.

Design of the remedial works was undertaken by a former Worley Parsons-Jacobs joint venture partnership, with construction support by Worley. Construction of the works was undertaken by Entracon as the main contractor, with Keller as the ground improvement contractor.

Notably, over the course of the works, Water Corporation was able to deliver cost savings by working with Entracon to process rock stockpiled from construction of the Ord Dam Spillway (rock quarried approximately 50 years ago) to use for the filter zones and weighting material. This use of material shows that sometimes there never really is waste material when building a dam.

Works on the site are nearing completion with final access works due for completion prior to May 2020.

Author:  Michael Smith Senior Principal Engineer – Water Corporation