Johannesburg is four seasoned - but we rally only look at 2 - Summer and Winter - we do not really have proper Springs and Autumns - they go very quickly. Our Winters are mostly at the worst -2 or -3 degrees celcius (at night) temps during the day are anywhere for 8 - 10 degrees celcius - so they are mild!
A borehole might be like what you guys call wells - it is a shaft which is dug into the ground - ours is about 70 meters down, they install a long cylindrical pump in there and it pumps water out of ground! Ours pumps enough water to fill a 10 litre bucket in 6,6 seconds - so if I did the math right that would be about 10 gallons a minute?
On the soil issue - our soil is varied - first we have alayer of topsoil probably about 30 - 40cm thick - then you hit the clay for about 60 - 70cm, and then you hit shale!!! I am not really sure what shale is - it might be clay which has compacted and formed into thin sheets of rock, or a rockish type material - but all I remember is that each pond we dug here was a major nightmare in sealing - not in terms of keeping the water in - but rather keeping the water out! We had to dig a trench deeper than the ponds so that the water would go there until we had dried and sealed the concrete!
If I go above the ground - which would be preferable then I do not have to get rid of the soil - I would probably have to either line the sides of the pond because of the top soil - or I would have to seal the entire pond with a bentonite. We have a variety of bentonite here - one which they call "Envirobent" (which they recommend for sealing of dams - as it swells to something ginormous!) - my only issue with it is that it has a pH of 10,5 (and I do not know enough to know whether that would be a problem and affect the pH of the pond to 10,5??????? and they have a "Calcium Bentonite" which they say does also swell, but not as much as the envirobent - it is more a water conditioner - so then the pond might leak? I am thinking about getting a bag of the envirobent and running a little test to see how much it affects the water (ie: 50 litre bucket - put envirobent in at the bottom) and test the water daily) - but I am not sure if this would be a waste of time on such a small test, and without the exact conditions - and provide inaccurate results???
There is sooooo much more to this than I originally thought - this has been a bit of a wake call for me - but at least I know what I am in for, and can try and do it right from the begining.
Thanks again guys for all your help - I really do appreciate it. About 2 weeks ago I was ready to get the TLB's in - now I am doing a lot more research!!!!
