We don’t use a filter system and have had acceptable results from water quality tests conducted on our tankwater.
A Davey electric pump supplies the tankwater for all uses in the house including showers, the dishwasher, the laundry, the hot water system and garden watering.
We have additional tap for Melbourne water in the kitchen sink e for some drinking and cooking use.
There is another Melbourne water tap under the house that can be used to fill the rainwater tanks should they run out of water.
We filled the rainwater tanks in late 2001 when we moved in after the house renovation. We have only needed to add more Melbourne water on one occasion in 2002 and on two occasions early in 2007 during the severe drought. This means we have been basically self sufficient for water for around 5 years.
Based on Melbourne Water’s estimated daily average water usage of 303 litres per person (as of December 2007 with Stage 3A restrictions) this means we have saved around 0.3 megalitres of water per year and 1.5 megalitres of over five years.
If the $3 billion allocated by the Victorian Government for the desalination plant were spent on domestic rainwater tank systems, this would equip around 600,000 households (at a unit cost of $5,000 for a tank and pump) and could provide up to 160 gigalitres of water per year that would otherwise be lost as stormwater. This equates to 165 days of Melbourne’s total water consumption based on the current daily usage of 992 ml, and it exceeds the estimated yearly production of 150gl from the proposed desalination plant.
However, rainwater tank supplies are of course not guaranteed due to ongoing reduced rainfall patterns.
It would appear that we could be better off if a much smaller desalination plant (say $1billion) were built and the remaining $2 billion spent on rainwater tanks and improved recycling of sewerage water currently sent out from ocean outfalls.
At the very least, we need radically improved public consultation about options for Melbourne’s and Victoria’s water strategy rather than unilateral decisions made in Spring Street following secret deliberations.
Logging in catchments and Melbourne’s water supply
In May 2002, the Victorian Government released a repost titled 21st Century Melbourne: a WaterSmart City. Strategy Directions Report.
A majority of public submissions for the study stated that logging should cease in all water supply catchment areas due to the impact on water quality and the reduction in long term water yields.
The report contained a recommendation to conduct a detailed and comprehensive investigation into the feasibility of establishing plantations to allow for the phasing out of logging in Melbourne’s water supply catchments
The report further stated that if plantation alternatives are confirmed feasible, an implementation plan to phase out logging from within the catchments should be prepared.
Potential water savings from the gradual phasing out of logging in the Thomson catchment by 2020 were estimated to provide an estimated additional average annual volume of water of 20 gigalitres (20,000 ML) in 2050.
In June 2004, the Victorian government released another report titled Securing Our Water Future Together.
This report stated that Melbourne’s original water catchments are closed catchments, are managed as national parks and that logging will continue to be banned in those catchment areas. It was found that improved water yields within catchments supplying water to Melbourne are important in securing Melbourne’s water supplies.
Actions to be undertaken by the Government were to:
- Undertake studies on the impact of logging on water yield of catchments in State forests supplying water to Melbourne;
- Develop options aimed at improving the water yield, including potential changes to management practices and phasing out logging in these areas;
- Assess the feasibility of establishing plantations outside State forests to offset any reductions in timber availability. This will be informed by the results of modelling and mapping work on high, medium and low-impact zones for plantations (refer Impacts of new plantation policy above); and
- Investigate the economic, social and environmental benefits and costs of these options.
On 16 May 2007 Environment and Water Minister John Thwaites stated at a public meeting in Ashburton that “work on the report is still in progress”.
In December 2007:
- The final report has not been issued and no date available for its release.
- No further community consultation has occurred.
- Logging continues unabated in Melbourne’s water catchments.
- About 30 gigalitres of water is lost due to logging each year, which is equivalent to about 150,000 households’ usage.
On June 19, 2007, in response to Melbourne’s dwindling water supplies, the Victorian government announced plans to build a $3 billion desalination plant at Wonthaggi to produce 150 gigalitres of water a year. The Victorian Government also announced that household water bills would double over the next five years to pay for a $4.9 billion water strategy to secure Melbourne's water supplies.
The water produced by the desalination plant would cost around $3000 a megalitre, based on Melbourne Water estimates, which means the net present value of the water gained by not logging the catchment, is between $1.1 billion and $1.4 billion. The cost of compensating the loggers to quit the catchment areas would be less than $40 million.
Scientific evidence indicates ending clearfell logging in Melbourne's native water supply catchments would eventually create an additional 130 litres per household per day, equal to 16% of Melbourne's present consumption.
It is now obvious that there is absolutely no balance in the Victorian Government's support for the logging of our water catchments. It is way past time for this to cease.
- Desal option doesn't hold water, Kenneth Davidson, The Age, December 10, 2007
- Bracks announces $5 billion water plan, Rachel Kleinman, The Age, June 19, 2007