Pete, Ron, Sorry, didn't mean to mislead anyone, the water above the falls is not a WS product, it is Envirotex, the two part epoxy. The ripples can be formed for a fairly short window of time, when the mix is nearly set up. For this pour, it was about 5 hours after pouring. Too soon, and the material just relevels itself. Too late and you'll either wind up with stiff unnatural crests due to the material not settling back some or the surface will be too hard to work. I use a pallete knife to dip into the surface and pull the material up. I found out years ago that this process causes quite a bit of suction on the riverbed bottom, as the material is lifted. This surface is just painted wood for my test and will be for the final application on the railroad. But years ago I poured the bottom from plaster, mixed thinner than normal so it would level. The plaster had been poured on plywood with some window screen tacked to it for something the plaster could hold onto. After painting the plaster and everything being set and dry, I poured the Envirotex, waited, and used the pallete knife to create ripples. Things were going well when all of a sudden, one of my strokes resulted in the plaster lifting off the screen. So, this is something to think about if you try this method.