"Nicholas Walker" wrote in message
...
I've recently scooped out an old silted up pond in my garden which filled
up
and overflowed every winter but dried out in the summer. It's a fairly
large triangle of about 20 yards each side. It takes four days to fill
with
a hose and then two days to drain. The clay base (of unknown thickness)
seems watertight, but I reckon it's leeching out where the clay meets the
topsoil sides.

What are my options? It's a bit big for a liner but I understand that the
clay could be extended up the sides. What is the technique for doing
this?
How thick does the layer of clay need to be? How do I test that the clay
to
be used is up to the job?

Many thanks in anticipation


Don't go there, believe me, It will do your head in, however thick the clay,
as the wind and sun evaporate the surface water, the clay will dry out,
contract,and send cracks down the banking.
I landed up bringing the bull dozer in, plenty of hardcore and then laced
with heavy chicken wire, followed by concrete, not cheap! but I have never
bothered since, It's called piece of mind.