This is the foundation for our best attempt at elimating slugs - we are trying to increase the number of frogs in our garden.
We collected some frog spawn earlier in the year, and made a temporary pond with a tyre, and some black plastic. This plastic will break down in sunlight, so we eventually need to make a nother bigger pond, and line it with pond liner. But the principle is good, and the water is clear, the plants and the tadpoles are thriving.
Our next pond will be made of a bigger type, and some pond liner, and eventually we may make a pond that is dug into the ground - maybe as we run out of topsoil for the raised beds :-)