Pond without rocks?

You can build a pond outdoors using no rocks at all. Use landscape timbers and stack them 18" high in any shape from a square to a rectangle to any other geometric shape. Use 16 penny nails to nail the timbers together. Line the inside with roofing felt as a cushion for you liner. Drop your 45 mil liner in, fill the pond with water. The liner is now sticking over the edge a few inches. Use a 1 x 4 to finish the top. You can use a 1 x 6 if you want to use it for a shelf for plants or rocks. If you want a waterfall, put one in one of the corners or build one in the middle. Looks great and is much cheaper than using rocks.