I was refilling the pond in my garden (it got damaged by ice) and noticed the huge range of sounds that I could make. Moving the hose around so the refilling water hit the rocks instead of the pond surface, changing the height of the hose or turn the water flow up or down, all created surprisingly large changes in sound quality. When setting up a water feature in a garden, or creating a fountain for a city square, you can make very different sounds by changing the design of the water flow.
A recent paper by scientists from Bradford University  have produced some new results about this. They put people in a special acoustic test room and played lots of sounds of water features at them and got them to rate the quality of what they heard. “Water falling onto small boulders so that there was considerable splashing due to the random nature of the falling water and the uneven surface of the boulders” was the preferred sound. However, you need to take, because there are some obvious sound effects that you wouldn’t want to make, for instance you wouldn’t want to generate a ‘urinal’ effect. The head of noise at the Greater London Authority once told me that water falling onto water is better than water falling onto stone. Indeed, attempts by the Bradford researchers to manipulate the sounds to better hide typical traffic noise were not successful. The listeners preferred naturalism in the sound. For that reason, you want to avoid constant streams of water falling onto flat water because that can sound like a municipal drain. The water feature shown in the picture looks ideal for creating a desirable sound (This is not my pond, which is much less grand!).
1. G R Watts et al “Measurement and subjective assessment of water generated sounds” Acta Acustica uw Acustica 95 1032-9 (2009).
2. Photo (c) Steve 2.0 http://www.flickr.com/photos/stephoto/2171148/