On Thursday, 8 December 2016 22:17:16 UTC, Andrew Mawson wrote:
"Tim Watts" wrote in message
...

On 08/12/16 19:23, Chris Hogg wrote:
On Thu, 8 Dec 2016 18:56:03 +0000, Tim Watts
wrote:

On 08/12/16 18:40, Chris Hogg wrote:

You may find that the auger holes just act as sumps and fill with
water no matter what you put in them, sand, gravel, whatever. If you
drill them down through the clayey layer to something more porous
below, then they may drain OK, but I'm not sure there is such a layer
from your description.

I've always wondered - how thick is a the clay layer likely to be (feet,
meters, 10's metres?)

Where are you? Some parts of the country, especially in the east, the
clay can be many hundreds of feet thick, although around Cambridge the
soil can be quite sandy, I believe.


Kent/East Sussex border...


Tim, if you search for bore hole data near you, you will get a full written
description of the sections of the ground through which they have bored:

http://www.bgs.ac.uk/data/boreholescans/home.html


Andrew

And a few yards away it could be different.
All large building project have a test hole dug to ascertain whats below.
Improving clay soil for horticulture is well documented and it doesn't include "hand augering".

https://www.rhs.org.uk/advice/profile?PID=620