Dam fun - part 1 :)

Our dam was dug when we first purchased our smallholding - along with the original incorrect foundations for our future house.  They say that a dam takes 3 years before it will hold water.  We purchased in 2008 - and it's now 2013.  The maths doesn't work LOL as it's held water, but not continuously.

So, in February we had to get the digger loader in to sort our the building rubble left over from the build.  While it was here RMan decided to make our dam deeper.  Oh, dear, does that mean another 3 - 5 year wait?

Building rubble - unsightly and, due to it's chaotic
pile, a potential snake hiding place

The building rubble was sorted in the wink of an eye...

The digger loader made light work of the pile of
rubble

... nice and tidy again :) (I think I'm in love with digger loaders...)

Then, the digger collected all the dry renoster bush we have so far removed from the land and piled it up next to the "rubble" pile.

The renosterbush we removed is now all
in one spot, instead of scattered round
the land

A few b-i-g scoops of clay from the dam were placed on top of the dry renoster bush - hopefully, the renoster bush will break down and create a sort of hugelkulture mound [hint: there are two separate links giving information on hugelkulture - on both the hugelkulture and mound words :) ]

Objective achieved

On the mound created by the building rubble we have thrown a slab, and have sited two 5 000lt rainwater tanks on top of it (with space for another two should we decide to add them).  This is the highest point of our relatively flat property, and, when our lower rainwater tanks are full, the water will be pumped up to the higher tanks, as it is the ideal spot to gravity feed rainwater down to the lemon trees and veggie patches next summer.

The digger loader at the start of the dam
excavation

With that sorted, the digger loader proceeded to dig the dam deeper - at least double the depth to 3.0 - 3.5 mtrs deep.

Dam deepening in progress

You can see from the photo below how deep the dam is - I can barely see the digger loader in the dam from the front verandah.

Can you see the digger loader?

MKids dog, Mandy, thought this was brilliant.  Once the digger loader left, she went to investigate.  She is absolutely moggy about piles of sand - of any size -and a newly dug dam - well, that's just one big sand pit :)  She ran, and ran, and ran - up and down, round the side, up and down - as though she had a skateboard beneath her feet LOL

Mandy - in doggy heaven

In the event of the future global warming drought scenario, we want to be as water secure as much as possible, so together with the 35 000 ltrs of rain water, and a 25 X 10 X 3.0 mtr dam (750mtr3 or 750 000 ltrs of dam water), we should be OK through dry seasons.  I think of it as bulk storage with a difference LOL

A few days later, whilst sitting and contemplating the dam from our verandah, RMan had an idea.

Briefly sketching it out to me when I was busy with something else, and wasn't listening properly, he proceeded with his plan...

Rugby posts?

Rugby posts in a dam.  What?!?!?  I can't remember the conversation...

To give you perspective, those gum poles
are 4.6 mtrs high (less 600 in the ground)

Leaving the cement  to dry round the base of the poles, he visited a Bentonite mine in Heidelberg - just down the N2.  Bentonite is an eco-friendly natural substance with a multitude of uses.

Zeolite inifo

Not only do they produce Bentonite, but they also mine Zeolite. Zeolite is the substance nearer the surface of the ground - Bentonite is further down, below the Zeolite.  (Clicking on the two pages of the phamplett which I scanned, you can see how useful they both are.)

Bentonite info

Having collected a mtr3 of bentonite noodles in our trailer...

Our trailer can hold 1.5 mtrs3 

...which got distributed via a wheel barrow...

One gets different grades of Bentonite -
the finer the more expensive.  We opted for the
cheaper Bentonite "noodles" - hopefully it will
perform as we anticipate

... RMan proceeded to "line" the newly deepend dam with the bentonite...

... more rugby posts...?

He was told to spread it out to 6cms thick and then to mix it with the surface clay - this was achieved with a rake - on a cool day - and even then he worked up a sweat :)

Bentonite mixed with red clay

Obviously, some of the principles from the General Science classes I attended as a primary school child stuck.  I had to try an experiment.

Lumps of Bentonite clay

So - 20gms of bentonite were placed in a bowl, and to that I added...

Bentonite and water

... 42 grams of water.

Bentonite and water slurry

After a bit of a stir with my (unscientific) finger the zeolite became a white muddy mess - well, it is a form of clay - just finer in structure - and white coloured :)  I added more water, and double the amount of red to white clay.

Settling of the clay / bentonite

Separation of the water from the two clays took no time at all...

The Bentonite / clay mix is much lighter
coloured than plain red clay

... roughly about 3/4 hour.  Far quicker than when one mixes plain red clay and water.  Bear in mind that our dam stayed muddy the entire time it held water, and the longest that lasted has been 4 months.

The mix is almost moonscapish in appearance

Not that easy to see, so I placed it into a glass and added more water.  Can you see the surface of the bentonite / clay mix underneath the water.  It looks amazing.  Sort of moon landscapish...

We very happy with this result -
one can clearly see the adhersion of
the red and white Bentonite clay :)

How hectic is that?!  The bentonite and clay soil has "binded" together, and the water is basically as clear as when it came out of the tap.  And this settlement took just a short while - seriously just 35 - 40 minutes.  It bodes well for our first heavy rain when the flood of water into the dam will cause a swirling, mixing effect...

We both can't wait... :)

Judging from the experiment, when, and if, we have water in the dam, and we need to pump the water out in the future, providing that we "scoop" out the upper layer of water, our pump should suffer no ill effects from the clay content.