Thanks to all for your input. I think I will try to separate the most highly organic material for disposal and use material with less visible organics blended with bentonite and see what happens.
I am working on a project in an area with a topsoil layer resting on top of sand and gravel. The proposed pond is likely to need a liner to maintain a constant water level during dry seasons. Due to the lack of clay soils, the idea was proposed to use topsoil as a lining material in lieu of...