A bi-monthly Council report just released on the progress of The Yass Water Treatment Plant Project has described how ‘raw water quality deteriorated to unprecedented levels in the Yass River/Dam in this extreme flood event.’ 

 The report acknowledges the critical role played by stage one works already complete at the plant and the staff operating it in keeping drinkable water available to the town and villages during the August flood. 

 ‘The Stage 1 upgrade works made it possible to run the WTP at a slower rate during the flood event in August 2022. This capability, together with the enhanced alum dosing system, enabled the operation staff to produce drinking water within the Australian Drinking Water Guidelines.’  

On August 5th 2022 Yass Valley Times captured this photo from the top of Yass Gorge

 For Background, the report notes that the upgrade of the Yass Water Treatment Plant is being progressed in three stages: 

  1. Early Works package includes installation of bubble plume aeration at Yass Dam, upgrade of

Raw Water Pump Station (RWPS) and urgent works at Yass Water Treatment Plant 

  1. Major treatment plant upgrades
  2. Rehabilitation of selected treatment process units in the existing WTP.

 Progress to date only extends to stage 1 works. The report advises that DPE Water maintains the view that effects of Stage 1 Upgrade on water quality need to be monitored over a period and reflected in Stage 2&3. The report also details ‘Council staff raised concerns about the security of the water supply due to risks remaining after the implementation of Stage 1 Upgrade. These risks relate to ageing electrical and control infrastructure, chemical storage and handling, workplace health and safety, and treated water storage capacity. A concept plan for Stages 2&3 is required to address these risks to avoid redundant investment and facilities. Based on the outcome of the consultations with HAF and DPE Water, the Deed for Detailed Design and Business Case will need to be renegotiated.’ 

 Progress to date includes – Treasury executed the deed for Stage 1, Construction Grant, for $2.543M on 14 March 2018. 

Budgets are allocated for Stage 1 Construction and for Stage 2 & 3 Design and Business Case development. 

Stage 1 – Early Works 

Long lead time items, including the compressor, dosing skids, electrical switchboards, and water quality instrumentation, have all been ordered. 

Tendering, evaluation and approvals of the work packages were completed by the end of January 2022 

Contracts were issued in early February for three works packages: 

− Electrical and mechanical works 

− Civil and Building Works 

− Integration Works (control systems) 

Works involve the followings: 

− Yass Dam (construction of pipeline and underwater installation of diffuser pipes in the floor of the dam) 

− RWPS (new electrical switchboard, control system, refurbishing of pumps and a compressor for bubble plume aeration) 

− Yass WTP (installation of dosing equipment for alum, potassium permanganate, water quality monitoring equipment, control system) 

 The NSW Treasury executed Funding Deed for $2,542,966 on 14 March 2022 

Construction works commenced in early March, and 80% of the works were completed at the end of July 2022. The following assets were completed and are in operation: RWPS: New switchboard and control system   

Yass WTP: New alum dosing system, water quality monitoring equipment and control system.  

 The report notes completion of the Yass Dam bubble plume aeration system is delayed due to supply issues with equipment for the operation of the compressor and flooding that affected the completion of the installation of the underwater aeration pipeline.  

 There are latent risks associated with the effects of the pandemic on the supply chain for equipment and construction materials. 2.2 Stage 2 &3 – New Water Treatment Facilities and Rehabilitation of Existing Facilities Consultations are continuing with DPE Water and HAF to seek guidance to progress with the Stage 2 & 3 design and business case.  

 Consultation with DPE (Water)  

The report notes Council continues to consult with HAF and DPE Water on Stage 2 & 3 development process and on the progress of Stage 1 Works.  

The next steps for Council are reported as follows:  

Complete Stage 1 Construction and commission new assets.  

Progress with Stage 2 & 3 Design and Business Case.  

Liaison and procurement for additional land for expanding the WTP site.