Securing Melbourne’s water supply

The Water Shortage

Less rainfall and much less water running into reservoirs means that Melbourne has to find 240 billion litres more per year by 2012.

Water shortfall

The problem is the amount of water flowing into reservoirs is dropping much faster than consumption. Since 1997, the total reservoir storage has dropped each year by an average of 100 billion litres. That is why the Thomson was full in 1996 and is around 20% today. In 2006, inflows suddenly fell to their lowest level on record and radically changed the timeframe for action.

The Melbourne Experience - inflows into major reservoirs

(Thomson, Upper Yarra, O’Shannassy and Maroondah)

Current and historical Water Storage graph

What does this graph show?
Annual inflows into Melbourne's four major reservoirs since 1913. While ups and downs are a constant feature, the average has dropped rapidly by almost 40% in the past 12 years. This included a record low flow in 2006, which the CSIRO had forecast could occur under a 'severe' climate change scenario in 2050.

Water savings are helping

Thanks to people’s water saving efforts, the amount of water Melbourne uses has also come down. Compared with the 1990s, households now use 35% less water and industry uses around 38% less.

The Perth Experience

Enlarge graph

What does this graph show?
Perth has experienced 2 major downward shifts to the amount of water flowing into its major reservoirs. Some experts suggest a similar pattern could be repeated in south east Australia, meaning that Melbourne may possibly see a second significant drop to its inflows.

Dam Capacity vs Water in Storage