Pump/Piping Design for Waterpark Lazy River

[DCunningham]

Does anyone have any knowledge on the design of propulsion systems for "lazy rivers"? I'm talking about the continuous flow rides that you see at water parks. I'm looking for the dictating equations for sizing pumps and the preferred layout (smaller pumps scattered around ride vs. one central pump piped to all areas).

I'm familiar with the design of pump stations and sizing pumps for vertical head and friction, but this is something new to me.