AN INVESTIGATION ON THE SOUNDSCAPE OF PUBLIC PARKS IN THE CITY OF BELÉM, BRAZIL A. C. Lobo Soares Museu Paraense Emílio Goeldi, Belém, Brazil. e-mail:
[email protected]
J. L. Bento Coelho CAPS, Instituto Superior Tecnico, Lisboa, Portugal e-mail:
[email protected] In urban areas, the acoustic environment is contributed by a variety of sound sources, with traffic being usually the most important. In large cities, public parks play a very useful role not only in social terms, by allowing the gathering of nearby residents, but also by providing escape areas where the environmental quality is better. In such areas, the sound quality is perceived as much better than in other parts of the city. The European legislation has been encouraging European countries and cities to set up or enlarge the use of quiet areas. Urban quiet areas, though lacking a formal definition, are usually understood as areas where a better sound quality is perceived, being less noisy and more pleasant. A thorough investigation is being conducted on the most relevant public parks in the city of Belém, North of Brazil. Located in a tropical region, Belém is a very noisy city. The soundscapes in the Museu Emílio Goeldi Zoobotanical Park, in the Batista Campos Square, in the Republic Square and in the Rodrigues Alves Botanical Garden are very rich, with noise from traffic but also with contributions from a variety of natural sources such as people, water fountains and animals. The parks, some with open access, others requiring an admission fee, are very used by residents and visitors who value the sound quality of the place. The study focuses on the aspects that make the soundscape appealing for the users in order to develop tools to apply in other areas to improve the acoustic quality of the city.
1.
Introduction
The current trend for world population growth points to an increasing concentration on urban areas, according to United Nations predictions. By 2050, 2/3 of the world population will live in cities. In 2008, for the first time in human history, the majority of the world‟s people lived in cities [1]. Today, Europe is an urban society where about 80% of the population lives in cities of variable sizes [2]. The urban fabric is then an increasingly important source of environmental considerations, since the citizens expectations of quality of life are also following higher standards. The quality of the acoustic environment is one of the leading indicators of quality of life and noise is a primary source of complaints in most cities. Local authorities are facing ever more complex challenges on noise reduction and on improving the quality of the local soundscape.
ICSV18, Rio de Janeiro, Brazil, 10-14 July 2011
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18th International Congress on Sound and Vibration, Rio de Janeiro, Brazil, 10-14 July 2011 In Europe, the Environmental Noise Directive (END) 2002/49/EC relating to the assessment and management of environmental noise [3] encourages the implementation and protection of quiet areas, though the definition of a „quiet area‟ has been under discussion for some time. The principle is the maintenance, protection and development of areas where the quality of the acoustic environment is good and where the citizens can find a pleasant soundscape and a relaxing sound environment with less aggressive components from mechanical sources. Urban gardens, parks and some squares may adequately fulfill these goals. The soundscape in urban parks is usually rather complex, where traffic noise, though with lower sound pressure levels than in neighboring areas, determines the overall sound environment, but includes natural components that associate with more pleasant atmosphere, thus contributing to the feeling of comfort, restoration and escape from urban noise aggression. Studies have been undertaken in urban squares and parks in cities both in Portugal and Brazil to better assess their soundscapes and to develop tools to improve existing parks. A thorough study was started in the city of Belém, in North Brazil.
2.
Parks in Belém
Belém is a rather noisy city with its soundscape mostly determined by noise from road traffic. The city is located 14 meters above sea level and has a population estimated at 1,392,031 inhabitants. The tropical climate allows outdoor use for large periods of the day, most of the year. Furthermore, the residents make use of balconies and terraces and usually have their windows open, even during the night. Four urban parks in the city of Belém with significant dimensions and with a predominance of natural elements, mostly vegetation, offering the public a diverse range of leisure activities [4-5] were selected for this study: Rodrigues Alves Botanical Garden (RABG), Zoobotanical Park (ZBP), Republic Square (RES) and Batista Campos Square (BCS). The selection criteria also considered their physical characteristics and real use by the population of Belém. Two parks (BCS and RES) have a 24 hours open access whereas the other two (RABG and ZBP) are surrounded by walls and public entrance is controlled. All are well frequented during the week and even more on weekends. Figure 1 identifies the four Belém public parks, all located well within the fabric of the city.
Fig. 1: Aerial view of Belem identifying four parks studied (Google Earth).
The Rodrigues Alves Botanical Garden (RABG) was created on August 25, 1883 as a reserve management of upland forest, now confined to a block of 14 ha in the Marco neighborhood (Figure 2), aiming at preserving the natural environment of the Amazon. Surrounded by heavy road traffic, it features animal species roaming free and several cages with mammals, birds, reptiles, amphibians and fishes from the Amazon. The RABG is open to public visitation with collecting fees from Tuesday to Sunday and holidays from 09h00 to 17h00. The RABG (Figure 3) offers visitors recreation spaces with children's toys, canoe trips on the lake center, kiosks and gazebos where chuan tai chi classes are offered on weekdays, toy castles 2
18th International Congress on Sound and Vibration, Rio de Janeiro, Brazil, 10-14 July 2011 caves and artificial water sources, lakes, bridges, cages with wild animals, small aquarium, orchid, sensory garden. The most frequent visitors are family groups on weekends and couples and groups of students during the week.
Fig. 2: Aerial view of Rodrigues Alves Botanical Garden in Belem (Google Earth).
Fig. 3: Views of the facade of the RABG in Belem (Lobo Soares).
The Emílio Goeldi Museum‟s Zoobotanical Park (ZBP) (Figure 4) was established in August 1895 in a central city block with 5.4 ha featuring specimens of the Amazonian fauna and flora (Figure 5), monuments and historical buildings. Located in the center of the city, the ZBP is easily accessible by the Belém population and tourists, being open to public visitation with collecting fees from Tuesday to Sunday and holidays from 09h00 to 17h00 [6].
Fig. 4: Aerial view of the Zoobotanical Park (ZPB) in Belem (Google Earth).
Fig. 5: Views of parrots in cage aquatic and upland flora of the ZPB in Belem (Luiz Videira and Lobo Soares).
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18th International Congress on Sound and Vibration, Rio de Janeiro, Brazil, 10-14 July 2011 This park was chosen given its socio-cultural and environmental relevance, as the most visited urban park in Brazil. It concentrates in a single city center area a botanical garden, a zoo, an aquarium and museum exhibition pavilions. The Republic Square (RES), dating from 1888, has a great prominence and importance in the urban context due to its historic significance and beauty. Its implementation follows the evolution of the city of Belém in the early days of colonization. It looks not as urban equipment (Figure 6) but as an open glade in the forest, distant from the first urban center and bordered by a cemetery for slaves and the population without resources. With reforms and improvements in public places, such as paving streets, installing decorative equipment, placement of monuments and gazebos, and especially the conformation of its landscape, with the delimitation of tours and internal gardens, the Republic Square won in the late nineteenth and early twentieth century, the contours and shapes that characterizes it today as one of the most beautiful and frequented in the city [7].
Fig. 6: Aerial view of the Republic Square (RES) in Belem (Google Earth).
The RES houses historical monuments such as the Peace Theatre (Figure 7a), the Park Bar, the Waldemar Henrique Experimental Theater, the Federal University of Para Arts Center and, on Sundays, a handicraft and regional products market (Figure 7b,c).
Fig. 7: Views of the RES, a) Peace Theater; b) Sunday market on the side walk; c) visitors in the Republic Square, Belém (Lobo Soares).
The Batista Campos Square (BCS) is circumscribed to a court in the district with 2.8 ha and has the same name since its implantation in the early twentieth century, formed by the Serzedelo Correia and Padre Eutíquio Avenues, and the Mundurucus and Tamoios Streets (Figure 8). The BCS is much frequented by neighborhood and other residents for exercising, walking, running, personal encounters, kiddies, dogs, cats and family leisure. Besides these visitors, its landscape is made up of cleaning officers, students from surrounding schools, street vendors, municipal guards and by passers. One can find white herons that nest in flocks in kapok (Ceiba sumahuma) (Figure 9) as well as small urban birds.
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18th International Congress on Sound and Vibration, Rio de Janeiro, Brazil, 10-14 July 2011
Fig. 8: Aerial view of the Batista Campos Square (BCS) in Belem (Google Earth).
Fig. 9: View of white herons in nests and in the floor at the BCS in Belem (Lobo Soares)
3.
Method
The soundscape study of the four Belém parks was started on June 2008. Very few studies on the soundscape of Brazilian urban parks were found in the literature [6, 8-12]. Field research was carried out to identify the soundscape of the four parks and its components and contributing sound sources. Sound maps were drawn for the Batista Campos Square (Figure 10a) and the Zoobotanical Park (Figure 10b). Photographs were taken and movies and sounds were recorded in all of them (Figure 10c).
Fig. 10: a) BCS Sound Map; b) ZBP Acoustic Map; c) RABG Map of collecting sounds (Lobo Soares).
The four parks were studied during the week and on weekends, in order to identify variations on their soundscapes as a result of changes in occupation and contributing sound components. Sound pressure measurements were made with class-1 sound level meters and recorded, together with meteorological parameters, such as temperature, humidity, and wind speed. The different existing sound sources were identified and qualified in terms of mechanical/natural, pleasant/unpleasant, sound/noise [6]. Soundwalks were taken in all corners of the four parks, on weekdays and on Sundays, when the parks receive a larger number of visitors, giving priority to the concentration of points near staff, visitors, children's toys, kiosks, sound equipment, musical groups, animals in cages and outlets selling food, handicrafts and toys (Figure 11). 5
18th International Congress on Sound and Vibration, Rio de Janeiro, Brazil, 10-14 July 2011
Fig. 11: The authors collecting sounds in field work at the RES and RABG in Belem (Lobo Soares and Milene Soares).
4.
Results
Rodrigues Alves Botanical Garden (RABG) Road traffic noise from the outside streets dominated in all measurement sites at the RABG, both on weekdays and on weekends. Sounds from braking near a bus stop alongside with honking horns and traffic cop's whistling were recorded. When the traffic stopped at a nearby red light and that contribution diminished significantly, the sounds of insects and small urban birds stood out in the overall soundscape. The most significant sounds produced by visitors were detected on weekends, and were made up of steps on the ground, talking, laughing, ball playing, biking, swings creaking, and especially the handling of "teco-teco” wooden toys sold in the park. Air traffic noise contributions from small aircraft and helicopters were very common, due to the proximity (1 km) from the Aero Club runway. The sound level differences between spots at the borders of the park, close to the nearby streets, and at interior points were found to be very marked, around 6 to 8 dB(A), thus creating much quieter and more intimate sound atmospheres inside the park, well appreciated by the visitors. Zoobotanical Park (ZBP) The ZBP is located in one of the noisiest areas of Belém, where noise levels between 60 and 70 dB(A) could be measured immediately outside [12]. Road traffic noise from the streets outside was recorded at different measuring points (see Figure 12), both on weekdays and on weekends.
Fig. 12: Sound pressure levels measured in ZBP [12]
Besides road traffic noise, ambulance, fire brigade and police sirens, advertising and automotive car sounds, fireworks, public and private building works could be perceived. Here, the highlights were the sounds produced by jackhammers, electric sander, hammer and "pile driving" at building works inside and just outside the ZBP, as well as central air-cooling of ZBP buildings and a of department store just in front. Visiting school groups with over 30 students produce high sound levels that sometimes dominate the animal sounds. Animals exposed in cages distinguish the ZBP sound from the others green areas of Belém. Among the birds are: macaws, parakeets, parrots, "ararajubas" and parakeets concentrated in adjacent cages. Among mammals, monkeys, giant otters and jaguars are those that produce higher sound levels. 6
18th International Congress on Sound and Vibration, Rio de Janeiro, Brazil, 10-14 July 2011 A variation of 15 dB(A), between 55 and 70 dB(A), was measured in the ZBP. Qualitative research with visitors highlighted the sounds of animals as the most positive and road traffic and building works noise as the most negative. Republic Square (RES) During the week, the soundscape of the RES is dominated by road traffic noise, which is supplanted by the sounds of parakeets in the mango tree. The presence of urban birds is less significant in this park. On Sundays, the RES receives many visitors for leisure purposes, attracting a large number of vendors, which produce sound themselves, sometimes with quite high levels. Figure 13 show different views of this park, with different events going on making up for very different soundscapes. Overall, the soundscape of the park was understood to contribute for the perception of differentiation from the surrounding aggressive sound climate, mostly contributed by road traffic noise.
Fig. 13: Views of the RES in different occasions (Lobo Soares).
Batista Campos Square (BCS) In this park, road noise was also seen to be present and dominant. Other sounds, however, make up the soundscape of the BCS during the week: by decreasing order of magnitude, the grunting of herons in tall trees, two fountains operating in the lake, coconut water selling tents, people walking and talking on the sidewalk surrounding, small urban birds. On weekends, other sounds are added: bell ice cream and popcorn vendors, plastic children electric cars, bicycles, dogs barking, children playing, screaming and crying, electronic and live music in central and cars advertisement circulating in the surroundings. In BCS, the areas with a more reduced incidence of noise are located under the trees near the water fountains, where the movement of light vehicles is reduced, there are no buses and the effect of masking of road noise by the pleasant nature sounds, such as birds singing and water, makes for a quite more pleasant soundscape [6]. These areas are those more used for visitors looking after pleasant changes from the outside road noise.
5.
Discussion and conclusion
Certain aspects of the globalized urbanization of Belém, present in all the parks studied, contribute to produce more similarities than differences in their soundscapes. The location of parks in the urbanized area of the city, with the intense surrounding traffic and the incidence of building works are the most relevant. The present stage of research showed that the four parks are affected by road traffic noise, with emphasis on motorcycles, noisy engines and brakes, and unregulated urban bus, as well as drivers who over use the horns or automotive sounds. In all cases, noise levels were seen to exceed those recommended by the NBR 10151, 55 dB(A) during the day and 50 dB(A) at night [13]. Also, in all parks the presence of noisy cleaning and maintenance equipment, especially lawn mowers, chain saws, pressurized water washing machines with, water pumps and, to a lesser degree, vehicles and equipment for waste collecting and transport contributed as negative sound components.
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18th International Congress on Sound and Vibration, Rio de Janeiro, Brazil, 10-14 July 2011 All four parks are affected by noise generated by construction sites located inside and outside, with the prevalence of sawing machines. The ZBP outside wall, 3 to 4 meters high, works as an efficient acoustical barrier. Sound level measurements have shown that the noise levels at the park edges are much higher than those at the central areas. The dense vegetation and the large number of wild animals in captivity at the RABG and at the ZBP attract many urban birds, thereby increasing the acoustical environment quality inside. On Sundays, both at the RES and at the BCS, it was observed that the good sound quality inside the parks degraded due to the noise caused by overload of visitors. The presence of natural elements in the parks, such as water fountains or birds, as well as quieter inner areas, contribute to reduce the perception of the urban road noise and to create a more pleasant sound climate than outside, which is consistent with the use of the urban park as an escape in the urban area for the visitor to rest and to find psychological restoration. The urban noise, mostly contributed by transportation or construction noise is a part of the soundscape in cities that can be perceived as an indicator of activity and dynamics by the citizens. However, it needs to be managed in the sense of non-interference with the urban sensitive uses and activities [14]. Urban parks can fulfill this mission, especially in large cities, where road traffic is intense and the resulting noise levels are high. Belém parks include a number of natural features, such as wild animals, both free (birds) and in captivity, water fountains that create specific soundscapes that seem to be well appreciated by visitors who find interesting landscapes but also the corresponding soundscapes that make a difference to the more aggressive noise in the surrounding streets. Other parks in the city can use these findings to improve their soundscapes.
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