These waterworks would need to be dropped from high flying planes, since the volumes of water needed would be heavy. They might even be incorporated into an airshow, another 4th of July tradition in the US. Explosions in water make impressive plumes of droplets and mist and would be a daytime substitute for fire and sparks. Properly crafted, all sorts of fountainlike effects could be achieved in midair. If deployed at the proper angle between viewers and sun, the waterworks might also produce rainbow effects. Finally, those standing below would get sprayed as the droplets came to earth - welcome on a hot day.

I must add that part of this show would consist of a flying Apache attack helicopter being doused from above with water, and hurling it in all directions with the blades.