Brandon Ballentine : The options that I am aware of are clay and gley. If you can get ahold of a large quantity of clay, say bentonite clay, or even just soil with a high clay content, it can be dampened and compacted to line your pond.

Another idea that Geoff Lawton shared in the PDC I took, is using manure as gley. This is basically anything high in organic matter that is forced to break down anaerobically (without oxygen). The way of accomplishing this that sounded best to me was to feed cows or other livestock in the bottom of the empty pond. As they gather there to feed, they will leave manure and compact it. You want to keep it wet. Eventually, the material will seal bottom of the pond. You will know this has happened when the water you put in is held in the bottom. When this happens, you move the feeding location up the edge to where water isn't holding, and the same process continues farther up. Hope I've described the process adequately.

Brandon Ballentine : The options that I am aware of are clay and gley. If you can get ahold of a large quantity of clay, say bentonite clay, or even just soil with a high clay content, it can be dampened and compacted to line your pond.

Another idea that Geoff Lawton shared in the PDC I took, is using manure as gley. This is basically anything high in organic matter that is forced to break down anaerobically (without oxygen). The way of accomplishing this that sounded best to me was to feed cows or other livestock in the bottom of the empty pond. As they gather there to feed, they will leave manure and compact it. You want to keep it wet. Eventually, the material will seal bottom of the pond. You will know this has happened when the water you put in is held in the bottom. When this happens, you move the feeding location up the edge to where water isn't holding, and the same process continues farther up. Hope I've described the process adequately.