I can relate a relevant personal anecdote on this subject. We have a lagoon
in the neighborhood where I grew up. It is where most of the stormwater for
the area runs into. Brisbane, being on level 5 water restrictions for most
of the last few years, is seeing a huge increase in water tank installation,
and this area is no exception. Over the course of the last 5 years I have
monitored birds at the lagoon and observed the natural rise and fall of the
water level. Last year, despite local rainfall being not much less than in
previous years, the lagoon dried out for the first time ever (despite the
drought it hadn't been below half-full before), and stayed dry for some
time. It is now full again. My point is, I believe that the large-scale
installation of rainwater tanks led to the wetland being dry in a slightly
lower than average rainfall year. So yes, I think it can affect local
wetlands to a degree. On the other hand, if the Brisbane River wasn't
dammed, the wetland was historically spring-fed so would never have run dry
in a normal flood/dry cycle.
Having said all that, I am still a firm proponent of people having water
tanks in their yards for two reasons. It lets the individual observe the
ramifications of their consumption (and therefore hopefully promotes
frugality or at least responsibility), and as previously said, it takes the
load off the remaining "natural" systems, whereas the wetlands that suffer
are mostly highly urbanised and not as much value as habitat for a broader
sample of biodiversity. If it came down to a choice between the Western
Treatment Plant and the Murray-Darling I would choose the river, despite my
Similarly I think each house should have solar hot water and solar panels
for electricity, and am hoping this becomes an affordable option soon.
On Mon, Aug 25, 2008 at 12:45 PM, Dave Torr <> wrote:
> True - there are winners and losers in most things. It is clear that our
> current use of water (at least in the Melbourne area and its catchments) is
> unsustainable with a growing population and probable decrease in rainfall.
> Desalination will involve getting very expensive water and lots of energy
> use. Taking it from farmers will cause an outrage and raises issues of food
> security. Improving irrigation channels by cutting losses will help - but
> again if all irrigation channels were covered to stop evaporation then
> wildlife would suffer. Sensible solution of course is to consume less.....
> 2008/8/25 Peter Shute <>
> > But that means the major rivers would benefit at the expense of smaller
> > waterways that aren't part of the catchments.
> > Peter Shute
> > -----Original Message-----
> > From: L&L Knight
> > Sent: Mon 25/08/2008 12:02 PM
> > To: Peter Shute
> > Cc:
> > Subject: Re: [Birding-Aus] Water tanks and wildlife (Victoria)
> > Taking roof loads out of the stormwater system would certainly reduce
> > the flash flooding in urban waterways.
> > Presumably the water in residential tanks would to some degree replace
> > water that is extracted from the waterways feeding the urban water
> > system.
> > Regards, Laurie.
> > On 25/08/2008, at 11:47 AM, Peter Shute wrote:
> > > There is, apparently, a proposal to "drop" water tanks as part of
> > > Victoria's water strategy. This is front page news in today's Age:
> > >
> > > and there is a full page about it in the Opinion and Analysis
> > > section of the paper (not online yet).
> > >
> > > They suggest that previous studies underestimated the amount of
> > > water household tanks could collect by 2/3, so their installation
> > > should be encouraged, not halted.
> > >
> > > The main article says:
> > > "Tanks can be important in reducing stormwater run off, which
> > > damages and pollutes waterways."
> > >
> > > Does this sound right? I would have thought that if you remove the
> > > fairly clean roof component of the flows in urban waterways, but
> > > still allow runoff from the roads, then the water that does reach
> > > the local creeks will be far more polluted than before.
> > >
> > > I've been wondering what effect it would have on the volumes
> > > reaching local waterways if all roof runoff was removed, as the tank
> > > proponents seem to be advising. I'm guessing at least a 10%
> > > reduction, far more in inner urban areas. So are we really "saving"
> > > water by doing this, or just stealing it from the local crakes and
> > > rails (etc)?
> > >
> > > Does anyone have any thoughts about this, and whether I need to
> > > worry about it at all? Should this issue be part of the water tank
> > > debate, or is the possible effect too small to matter?
> > >
> > > Peter Shute
> > > www.birding-aus.org
> > > birding-aus.blogspot.com
> > www.birding-aus.org
> > birding-aus.blogspot.com
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