Question
We have a lot of red clay here on our land, and I am putting in a pond in.  I have the hole dug and ready to put in the liner, but I was told by a friend that he had a pond and water would get under his liner and float it up because of the clay soil.  Do you know if this would be the norm. If it would be a problem, do you know of anything I could do to prevent this from happening, other than concreting the pond, instead of using a liner?  Your help would be deeply appreciated.

Answer
We have heavy clay soil here.  My liner has never floated up.  The liner may float up if you have a high water table or improper drainage.  If you think drainage may be poor, you can build a drainage system under the pond.  Basically, if you put in a layer of fine gravel, you could have that drain to a low end and then drain out via pipes with holes in it or something.  You want to also prevent water from draining in the sides of the pond.  That means diverting any drain spouts below the pond and/or putting in a trench with rocks and PVC piping at the high end of the pond that leads down to the low end of the pond.

See http://www.fishpondinfo.com/ponds/pcare2.htm#liner for my small section on floating liners.

Good luck!