Is this what you're thinking about? All I did for this is; make a terrain, flatten it so it's just ripples and put on a sandy texture. Add a water plane with the water mat that you wish. Duplicate and resize just a tad. In the Water and Liquid mats is one called "Mr Bubble", Texture your last water plane with that. Work with adjusting the transparency and reflectivity. Hope this helped in some way. :)