In that situation it will form a layer over the water layer.

The dark tannins in the fresh water layer makes it difficult for light to penetrate.

Finally, carefully float a layer of mineral oil on the water layer.

By 1975, the upper water layer was saltier than the lower layer.

The fresh water from the melting ice makes up a water layer on top of the sea water.

Fresh water layers have been observed to spread through the Sound at 0.9 metres per second.

If it does not, the car will hydroplane, rise up on top the water layer, even at rather slow speeds.

We also have water layers sandwiched between them.

I have read they are open water layers, so what type of stones do I need?

"Rock and ice, probably with a liquid water layer under an ice shell."