I had to start a new thread for this as my news server kept rejecting my
reply (perhaps it is a laissez faire capitalist machine).

songbird wrote:
David Hare-Scott wrote:
Billy wrote:

In a few years, if you want a breath of fresh air, you'll be able to
buy it at a store.

We are hoping for a couple of hundredths of an inch more rain
tonight. Wish us luck.

Here we have a concept related to rainwater called 'harvestable
right' . It means that roughly 10% of the rain that falls on your
land is yours to do with as you wish, the rest must available for
the environment or be allowed to run down to the rivers for others
to use. In practice it limits the size of the dam you can build and
the kind of waterway you can build it on. If for example a
permanent river crosses your land you can't dam that.

that first part seems somewhat odd, as it would
likely help moderate and encourage ground water to
have a higher percentage available to be held back.
as it will eventually get into the creeks/rivers
eventually.

the second part i would agree with, because by
damming those sorts of waterways you would likely
be interfering with fish migrations or perhaps
raising the temperature of the water.


On top of that if you are on "permanent" fresh water, a river or
lake, you can pump from it (while it runs) without charge for 'bona
fide domestic purposes'. This includes stock watering, human
consumption and gardens. There is no specified limit to this in
terms of volume although if you were taking huge amounts somebody
might come around and ask exactly what you are doing with it. If
you were irrigating on a commercial scale or selling it you would be
fined. If you want to irrigate on a commercial scale you have to buy
a water license.

that makes sense, but those who get there first
in a situation where supply is declining would
be those who would get it. sounds like eventually
there will be rationing when enough people want
to draw on it.


Any attempt by government to take away any of these rights would
have dire consequences at the ballot box, as despite the fact that
Oz is very urban the cities have a romantic attachment to the 'bush'
and a well organised campaign by farmers would gather many votes.

For the small landholder and those running sheep or cattle this is a
good system. As for irrigators it seems they are never happy
regardless of government, policy, rainfall or anything else.

for the longer term i think the ground water
situation would benefit from a higher percentage
of capture of rainfall. has anyone tried to
increase that percentage?



Your idea doesn't work because:

- Irrigation water is held in dams that don't leak (or shouldn't) so that
doesn't lead to groundwater recharge.

- The more that is held in dams the more that is lost to evaporation which
is not useful to anybody including the downstream ecology.

- It is used for irrigation where most is lost to evapotranspiration not to
groundwater, if your irrigation is soaking down below the root level you are
doing it wrong and may be raising the water table and so contributing to
salination. This has happened in too many irrigation systems around the
world including the Murray-Darling.

- The figure was arrived at to allow sufficient flow in the rivers for
environmental, agricultural and domestic purposes downstream, many rivers
cease flowing none the less in dry times. If the figure was more it would
be favouring those where the rain falls at the expense of those users
downstream. And yes higher figures have been suggested by those who would
benefit at the expense of others.

You must also take into account that the system must respond to el nino - la
nina cycles as well as any seasonal pattern. This is not a reliable annual
rainfall nor a reliable seasonal pattern such as annual snow-melt. It's a
hard land.


David