Stretching Our Water Supply !

 Warragamba dam is now overflowing and we are assured that means that Australia's biggest city has five years worth of water in storage.  Despite this, water restrictions are still in place and there are no immediate plans for them to end.  Despite the water flowing to waste over the spillway there is a lingering doubt about water quality.

Global warming is delivering ever hotter summers and this rise in temperature is creating blue/green algae blooms and these are compounded by the run off from nearby mining operations and the growing cascade of polluting business activities in the catchment area.  Despite the dam reaching capacity, our desalination plant is still running and producing drinking water to add to Warragamba to raise the level of water quality.  Recent  flood rains washed ash from last years bushfires into the water stored there and that is decreasing visible clarity.

The water Warragamba delivers to the homes of Sydney citizens is classed as " drinking water ", and yet the vast majority of it is used for other purposes.  We flush our toilets with drinking water and the vast amount used to water parks and gardens must meet that quality standard.  The water used in food production needs to be of high quality, but many industries use water for industrial purposes where that is unimportant.  All that water eventually ends up discharged out into the nearby ocean.

The problem is the city of Sydney keeps ever growing and the catchment area that services its water supply is finite.  Unless we are to face a serious future water shortage we need to reclaim and recondition that discharge water and pipe it to where usage does not need to attain drinking water standards. The taps in city housing needs to deliver drinking water but some industries can run successfully with water of a lesser quality.

Technology is now able to recondition waste water to a high standard and piping reclaimed water to individual industries which high usage for an industrial purpose where lesser quality is acceptable would improve the capacity of the city water supply.  It is unlikely that housing will ever have a dual supply because of the cost of the infrastructure involved, but supply to selected industry would involve a lesser distribution network.

One of the tactics to reduce the demand for drinking water would be to zone areas for heavy industry with a high water use need which could be met by recycled water to where it could be economically distributed. Such clusters would reduce the draw from Warragamba and make the city storage capacity last the city well into the next century.

A hotter climate probably means that in future water from Warragamba may need to be reconditioned before it is put into household water supplies because of the effect of algae blooms on drinking water quality.  The sheer volume involved would be impossible unless the amount required to meet drinking water standards is substantially reduced, and that can only be done if industry can be convinced to use recycled water.

The technology exists to achieve this. Drinking water is too precious to be willfully wasted !