From the blog of the Australian Tea Party:
This is the most rational argument I have ever heard about Water in Australia. I always believed that it was silly to talk about water restrictions in a country like Australia which has only 21 million people. I think the Australian Tea Party needs to improve its website but I think the ideals they talk about are something which I connect to.
So yes Australia does have meager water supplies compared to the other continents, but these figures lack relevance unless we consider two other vital factors. Australia is the smallest continent on earth and much more importantly we have a miniscule population in comparison to other continents and countries.
If we look at a comparison of precipitation per head of population, which is much more relevant, we get a dramatically different picture.
Water per person from annual precipitation from various countries:
Australia: 122 megalitres
Brazil: 121 megalitres
United States 29 megalitres
China: 11 megalitres
Japan: 5.9 megalitres.
United Kingdom: 2.6 megalitres.
Leaving aside ground water for now, Australia has another source of water.
Because most of our cities and towns were originally built on river estuaries, for obvious reasons and because no thought was given to the collection of runoff from roofing and pavement, most of our storm water runs into the sea unrecorded in run-off figures. While the quantum of this is not known, estimates of around 40 million megalitres annually are considered reasonable. Most of this run-off occurs on the eastern seaboard.
So, how much water do we need?
For each Australia household to have all the water we need to live what we consider to be the Australian lifestyle. That is, have a garden with lawn on which we wash the car when we feel like it, have a pool for the kids and generally not have to be concerned about water use or shortage.
We need 110,000, litres per person per year.
This figure includes all domestic use, Council and industrial use, but does not include Agriculture and Mining. Therefore for every 9 people in Australia we need 1 megalitre of water per year.
Let us assume that with some rational planning we did the following:
1. Collected and recycled just 5% of urban runoff = 2M megalitres
2. New dams to collect just 5% of river runoff = 14 M megalitres.
Total 16 million megalitres; that is sufficient for 144 million extra people.