Soundscape design and mapping of water features used over road traffic noise

In order to develop a better understanding of the soundscape design of water features, this paper examines the effectiveness of different water structures used over road traffic noise for promoting relaxation. The work presented focuses in particular on sound mapping design, in view of identifying how appropriate water sound levels can be achieved through different designs. The analysis was carried out for a wide range of small to medium sized features typically used in gardens or parks, and sound maps of the water generated sounds were developed through the use of propagation models based on either point or line sources. Three acoustic zones (‘water sound dominant zone’, ‘relaxation zone’ and ‘road traffic noise dominant zone’) were defined by taking into account quantitative criteria based on water features’ perception. For example, the ‘relaxation zone’ was defined as the zone where water sound levels are similar or not less than 3 dB below road traffic noise, based on preference findings. The three zones were calculated over a 20 m × 20 m area for all the waterscapes considered, and for a range of different road traffic noise levels. This allowed identifying optimal distances from the features where relaxation can be promoted.