my head was not the only one to turn in the direction of the river at the sound of the water , and it was then that i saw that the waterfall that i had understood was to be switched on later that evening was actually in full flow ; a powerful chute of water spurting from , i presume , the very top of the building - it was impossible to see the exact point of origin - out in a wide arc so that the droplets fell to earth in a wide crescent across almost the complete width of the taedong river .