I have spent a lot of time on these developed communities with their own lakes. Many times they are less than five acres, but they appear to have a concrete type bottom that goes out to the sides as well. Does anyone know what kind of material this is? Can it be used in something that is going to be 20 acres and around 30feet deep? It seems to be a great solution to losing water to permeation, setting up structure would be easy and aeration would be easier as well.

Any thoughts on this or what this material is called?

Thanks

James