David Hare-Scott wrote:
songbird wrote:
David Hare-Scott wrote:
songbird wrote:
David Hare-Scott wrote:
....
No. My area is failrly high rainfall about 1100 mm PA but can come
at any time of year. Nothing for three months and then 200mm in a
week is not uncommon. This is from normal variability. If we have
el nino we can get as little as 300m or in la nina 1800mm in a year.

that seems to really cry out for swales and
catches...

No the fainfall is too high, in a wet spell with clay soil it would remain
waterlogged for too long.

smaller and wider swales/catches then. you can
always adjust them as needed.


As it is I have to plant all my fruit trees on
mounds and build up the vege garden so water doesn't sit in it. The heart
of the problem is that you must have a compromise between the design that
suits very wet and very dry conditions because you will get both at
different times.

well true, but when someone says they have intermittent
rains with months in between then that tells me that they
want to capture every bit of it. how to do that is the
fun part.


The same applies to house design. You have to deal with a temperature range
from -7C to 44C and very low to very high humidity which is not the same as
a cool temperate area where you get (say) -20C to 25C where you want to get
the sun into the house all year round or tropical where you want to keep it
out all year round. As I said its a hard land.

here it rarely hits -29C or 41C, but those
are possible extremes. so we need a dual
design which works to both let in light in
the winter and to not let it in during the
summer.

we also have low to high humidity conditions
in almost every season.


i thought you managed to grow a decent pasture on
a part of your property? you don't get that in
unreliable arid climates without sequestering a
significant amount of rainfall...

It is done in two ways, by having clay subsoil that acts as a big
sponge and ensuring the topsoil has high infiltration so that it
collects all but heavy falls. The first is from choosing the right
block the second from good management. I can have grass growing
for up to two months after the last rain.

right, and that second bit is kinda my point,
that you do manage your property well so that it
does capture the water that lands on it. i would be
surprised if you are losing 90% of it to run off.
i.e. those pastures are recharging the ground water
at some level and are contributing to a longer term
flow for the water shed. probably also suffer very
little erosion too.


Perhaps I didn't explain clearly in an earlier post. You are allowed to
impound ~10% in practice this limits your dam size according to a formula
based on your land area and rainfall. It doesn't mean the other 90%
necessarily runs off.

ah, yes, that's clearer.


songbird