Reducing Domestic Water use in Residential Gardens|
Issue and Stakeholder Briefing|
To the desk of Hon. Bill Marmion. Minister for Water and Environment This policy brief brings to light the issue of household water consumption in Perth, particularly the need to examine the potential for large scale water savings in the domestic sphere. Domestic water use is nearly double that of Melbourne and Brisbane, whilst local water supplies are critically low. This brief summarises the history of water usage in Perth, it accounts culturally for the reasons that we use so much on our gardens. There is a section that outline the dimensions of issue, who is using how much? The benefit that multi-story housing has on water consumption, as well as the socio-economic gap between the high income earners and on average their tendency to have a higher instance of garden ownership and the use more water generally. Finally this brief will inform the reader on the relationships that interact with the issue, particularly the levels of government and how each one interacts. As well as governance, there is information on the complex interaction between the public and the policy makers.
In order to conserve valuable water resources policy makers have to analyse the current water use situation and identify key areas where consumption can be influenced or if necessary forced. Currently the Water Corporation identifies ex-house usage as the area with the biggest potential for reduction, as shown in figure1, ex-house usage vs in-house usage. Ex-house water usage is a term used to describe all private citizen water usage that doesn’t occur within the house; this can extend to pools and ponds but is largely comprised of garden and lawn use. Domestic water usage per person in Perth is twice that of our east coast neighbours Melbourne and Brisbane, in addition to having the lowest annual rainfall it isn’t particularly surprising that Perth’s’ future water outlooks are the bleakest.
Historically water usage has always been high as water rates and restrictions were not imposed until the late 1960’s where a ‘pay as you go’ scheme allowed 150Kl of water per household per annum, then a charge for every extra kilolitre. This lead to a halving of usage from 508kl in 1975/76 to 288kl in 1977/78. Since this point in time there has been very little further reduction per capita and since the population has increased immensely the strain on supply has never been greater.
The cause of this high water use in the garden is both cultural and environmental. Perth is largely build on sandy soil, in a lot of areas the original soil is beach sand. These sandy soils are very inefficient due to their inability to retain moisture and nutrients, thus requiring more water relative to other soil types. And the nature of rainfall in not befitting of the exotic and ‘English’ style gardens that have been traditionally grown since settlement. An important point to take into consideration is that owning a detached house on a quarter acre block with a lawn and garden area was the aspiration of Australians since post WW2. Significant because it represents the defensive nature the many perth residents take towards water usage in the garden, as the cultural norm. It also explains the large disparity between the number of detached homes and the number of higher density dwellings.
Figure 2 highlights 2 dimensions to the problem of ex-house water usage in Perth, as discussed above the social tendency to reside in detached private residences is an issue because they on average are a less efficient in their use of water, (no multistorey vs multistory). The differences in use can largely be attributed to the 6% difference in water usage ex-house as shown in figure1 but also the relationship between the housing density and the average income. People of lower incomes are over represented in multistory housing because it...