Planificación acústica. Estudio y conservación del paisaje sonoro en un contexto rural

Every rural area, every quiet zone, has a peculiar soundscape, a natural value the preservation of which is essential. Its acoustic environment is dominated by the noises of nature: the whisper of the wind in the tree canopies, the birds singing, the sound of rivers, wildlife... Nevertheless, human beings have their role in the configuration of this environment. In rural areas infrastructures, industries, settlements, forestry, agricultural activities, recreation areas, etc., also can be found whose noise shouldn’t be dominant. In this way, a quiet area can be configured in which sound events could have their origin in anthropic sources, but always in a harmonic relationship with the sounds produced by nature. This work aims to establish a first approach to a methodology to characterize soundscapes in rural areas, and in this manner, to correct deficiencies shown by the current legal framework in this field. The study is developed in a rural area of 720 ha in the NW of the municipality of Lancara, in the province of Lugo, Galicia, Spain. Starting from the review of diverse literature, and a comprehensive field sampling, the use of a number of acoustic indices is proposed which, through a compounded approach, will allow a first draft for a local soundmap. A total of 31 sampling points were surveyed, and between 3 and 9 measures for acoustic level were performed of 15 minutes each during the daylight period (7:00h – 19:00h). Then, noise recording, meteorological data sampling, identification of sound sources and the annotation of any incidence which could be relevant for a later analysis were made to characterize the acoustic environment. In addition, propagation of anthropic noise from each sound source was simulated. Depending on the land cover, relief, atmospheric conditions and the sound level and frequency spectrum of each source, sound propagation maps were derived, as well as maps showing the excess of noise generated by the anthropic sources in relation to the noise of nature. With all this material at hand, a representation of the soundscape is obtained. In such, we can differentiate those areas where the anthropic noise is dominant from other where, despite high sound levels, dominant noises come from nature; and on the contrary, from areas where even when sound levels are low, the dominance of noisy events originated in anthropic sources breaks the area’s quietness. Finally we are able to establish those areas considered as quiet by the experts, those in which the nature’s noise is clearly dominant and where the place is characterized by low sound levels. Land Use Planning should rely in an adequate methodology for the characterization of soundscapes as a basic instrument for the management of rural areas. It is expected that the results of this work would contribute to the development and consolidation of such methodology, with the final objectives of defining conservation priority zones, assessing the carrying capacity of the area for the development of any activity, the analysis of acoustic impact, and the contribution to the conservation of the characteristic soundscape of every rural area, every quiet zone.