Building Scenes with Lakes and Ponds
Rule One when making the outline for a lake or pond is a good, solid foundation. I learned that the hard way many years ago when one of my small lakes sprung a leak and the water slowly leaked out. I never did find that leak. All the water just disappeared under the layers of scenery. So I turned the lake into a swamp. It looked fine but…oh, well.

Use plaster and Sculptamold around and under the lake. Do not just build a shoreline and leave the bottom undone. It will leak. In other words, make a small bowl – but a bowl that has a rugged shoreline. Don’t just make a circle and call it a lake. Nature doesn’t look that way so use your imagination.

Like always, paint the plaster and/or Sculptamold flat black. Keep the bottom of the lake black but paint the shoreline and add scenery touches before you pour the water. You don’t want a dull, lifeless black bottom unless you’re trying to give the impression of a deep lake, which may only be near the center.

When adding shrubbery, weeds, etc. around water remember everything generally gets greener the closer it gets to water. So use dark green course turf and/or lichen along the shoreline and the greenery may get progressively lighter as it gets farther from the water.
And speaking of lichen, if the terrain is steep you will probably need to use nails or pins to hold it in place as the glue dries. Once it has dried, add the course turf as described in the basic scene.

I’ve tried a number of different water products and I think the best is Realistic Water by Woodland Scenics.
IMPORTANT: Add thin layers of the Realistic Water at a time. Do not simply pour half an inch, or even a quarter of an inch, all at once. Do it in thin layers and pour as slowly as possible.

If you pour it too fast you may get bubbles. If you do, use a toothpick to remove all bubbles.
Allow days for the water to dry. It takes time. Then, if need be, add another layer of water.