Conference Papers | 2008 Victorian Conference Papers

MANAGING COMMUNITY WATER SUPPLIES DURING RECHARGE OF THE YARRA VALLEY CONDUIT
Daniel Ellis, Lead Operator, Melbourne Water Corporation
Kathy Northcott, Senior Water Treatment Engineer, Melbourne Water Corporation

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ABSTRACT

The Yarra Valley Conduit (YVC), along with the Yarra Silvan Conduits (YSC) move water from Melbourne’s Thomson and Upper Yarra catchments into the metropolitan transfer system, via Silvan and Cardinia reservoirs. The Upper Yarra townships drinking water supplies are also taken directly off the YVC. A storm event in June 2007, where around 230mm of rain fell in the Upper Yarra and Thompson catchments in one night, resulted in high turbidity in the Upper Yarra reservoir with increased sediment deposited in the YVC. The transfer strategy for the 2007/2008 summer was to increase flows in the YVC significantly to meet the summer demands of the Silvan and Cardinia reservoirs. It was identified that this would create turbidities in the YVC much higher than experienced previously.

In order to prevent impact on the Upper Yarra townships, as well as the downstream reservoirs, the following plan was implemented:
• Conduct a sharp controlled increase in the YVC to flush out as much silt in as short a period as possible, and
• Change the Upper Yarra townships over to an alternative disinfected water supply during the flush.

This paper describes the challenges occurring as a result of the Upper Yarra turbidity incident, and the planning and implementation of the alternative disinfected water supplies to the Upper Yarra townships during the subsequent YVC recharge.

KEYWORDS

Storage reservoir management, turbidity, disinfection, incident management