I have my pond drained due to a leak at the base of the damn where water is working its way through the rock layers. The contractor and I are working to re-smear the botton, add more clay, put bentonite on and then more clay. However I have read several places were folks have used geo-fabrics on the bottom to help keep the material from continuting to wash into the rock. I just want this to be the first and last time I have to drain it for a leak and am thinking of adding it as belt and suspenders.

Does anyone have suggestions on which of the many materials to use. Not looking for the PVC liner here, but rather the fabric that will just keep the material from washing into the rock.

Thanks!