Thames Landscape Strategy - Hampton to Kew -

Arcadian Diary March 2007

Arcadian Diary by Jason Debney
One of the draw backs of living in a large city like London is the constant noise. This can be from many different sources such as radios, aircraft and road vehicles or simply it is the background hum generated from seven million people living in such a small area.
Noise is particularly detrimental to wildlife causing stress, hearing loss, disruption to the breeding cycle, communication problems and retreat from favourite habitats. In some instances animals have even changed their habits quite dramatically in response to sound pollution. Great tits for example can have a much faster and higher song in urban areas than in the countryside to compensate for higher noise levels and even marine mammals and fish can be affected by strange noises.
Under the EU Environmental Noise Directive, the UK Government has a duty to identify which areas of the country are noisy and which are quiet – in effect they are producing a noise map of the UK. From these maps it is hoped that quiet areas can be identified and designated as tranquil spaces. These will be based on a series of tests including land type (such as proximity to a conservation area, metropolitan open land or registered park or garden of historic interest), actual noise level and the source of any sound. We are well placed in our part of the world to have quite a few quiet zones due to the large number of parks and gardens , however, it is ironic that the Government’s mapping criteria does not take into account noise from aircraft!
Mapping levels of sound is not as easy as one would think. Recent research has shown that what constitutes noise pollution is different to different people. What is pleasurable to one person is a cacophony to another and interestingly there are many factors involved. Take music for example. Age is seen as the principle factor determining whether music constitutes noise pollution or not but this only tells half the story. Across all age groups people disliked piped or loudspeaker music in the open air whatever type of music it was whereas open air live music was almost universally liked (the type of music did not appear to be a factor). What people enjoyed was the interaction with the performer making the sound a pleasurable one.
Beaches are another good example of how different noises stimulate us in many varying ways. Technically a beach is actually a very noisy place – the sea crashing against the shore is often at a sonic level higher than that of an airplane. The sound of a beach however, is not classified as pollution as tests have revealed that almost all people enjoy this sound finding it restful to listen to. This shows that it is not just the level of the sound that is important but what the source of the sound is, whether it is manmade, the distance it has travelled from and how temporary is it. The thrill of the unexpected can also be a positive factor in appreciating sound – for example Concorde may have been by far the loudest aircraft in the sky but how many of us cannot say that when it flew over we did not stop and stare skywards.
The level of noise is determined by a myriad of different factors. Traffic for example is noisy (and almost universally disliked) because it is pitched at one frequency which is particularly offensive to the human ear. Another factor in determining noise level is the ‘ground effect’. Noise carried across water has a different level to the same noise carried across snow, grass or ploughed fields. It is surprising that the effect of trees has only a minimal effect in combating noise pollution. To reduce sound levels a tree line must be at least 30m thick and contain dense vegetation from the ground to the top of the tree line. Conifers are better than deciduous trees and the wood needs to be downwind of the source of the noise.
Having determined what constitutes noise pollution and mapped quiet places, researchers are now looking at those every day noises that are found to be pleasant and actually contribute to what is known as the ‘positive soundscape’. Across the UK people are being asked what everyday sounds they think are characteristic of their local area – what is special about these sounds and why they are valued. From this it is hoped that patterns will emerge and a soundscape map of the country can be produced allowing for lost sounds to be identified and cherished sounds conserved.
This idea of soundscape was introduced to me only a couple of weeks ago and has really opened my ears to different sounds and what noises are unique and special to any given location. In south west London for example, one of the defining sounds that adds to the character of the soundscape are the parakeets and along the river a whole series of noises are found that are quite unique to that particular environment.
In a recent survey the sound that was voted London’s favourite was the old Routemaster bus bell. This was chosen for many different reasons. At its simplest level, the sound of the bell was synonymous with the end of the journey and arrival home but other reasons given for liking the sound were much more complex. The noise of the bell was representative of an ‘old London’ and in particular it was associated with a lost but much loved London landmark (the Routemaster bus) that many people did not want to see replaced. In addition, to make the noise involved activity and the resulting sound could be controlled at a human scale and was perceived as a natural sound. The bell could be pulled at different strengths making for many different levels of noise. This has been termed ‘ sonic diversity’– a similar concept to biodiversity in that the more varied the sounds we have, all positively contributing to the soundscape the better. In replacement to the old Routemaster bell, bus companies have introduced a uniform electronically generated buzzer that plays recorded sound warning people that the bus will soon be stopping.
In an increasingly uniform world, loss of sonic diversity is being recognised as an important issue in the conservation and design of places and objects. This is similar to the way that we conserve biodiversity or historic features. It is hoped that this national soundscape project will identify what people cherish so that these sounds can be preserved for all to enjoy.

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