Landscapes are composed of objects, units or elements of different nature. Interaction between these elements creates a non- random organization aggregates and patterns. Such patterns emerge at related spatial and temporary scales. Design Elements create moods or feeling for the Observer.

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INTRODUCTION – Landscape elements
Landscapes are composed of objects, units or elements of different nature. Interaction between
these elements creates a non- random organization aggregates and patterns. Such patterns emerge
at related spatial and temporary scales.
Design Elements create moods or feeling for the Observer.
INTRODUCTION
NOISE CONTROL
Noise control is the reduction or elimination of unwanted sound in the landscape. The science of
sound control in the landscape involves much more than the simple quantification of data. The
quality of sound may be as important as the quantity of sound. Some sounds can have profound
psychological effects on people. For example, the constant drone of cars on a highway is rarely as
offensive as the squealing of brakes at an intersection. Masking unwanted sound (by falling water,
for instance) is a technique which can mitigate noise disturbance by modifying the quality of the
sound received by the ear.

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BASIC APPROACH TO NOISE CONTROL
There are two approach to noise control in the landscape include Acoustical Planning, where
potential noise problems are minimized during design stages, prior to any construction, and
Retrofitting, where noise problems are mitigated by alteration to existing developments.
ACOUSTICAL PLANNING (PRE-PLANNING)
Where acoustical planning is possible, setbacks and other methods can be employed to minimize
sound transmissions. Acoustical planning should be part of any land use planning project, especially
with major projects such as airports, highways, and railroads. Acoustical models should be
developed and tested to assess the planning implications both on and off the property.
Acoustical planning is advantageous because as potential noise problems are identified, cost-saving
mitigative measures can be taken to reduce noise levels to acceptable standards while at the same
time designing a physical landscape with improved visual qualities. This can be achieved, for
instance, through grading concepts that retain significant natural landforms and existing
vegetation, as well as incorporate noise buffer mounds where necessary. Preplanning can
accommodate public and private interests by reducing noise to acceptable levels, while retaining
landscapes of high quality.

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RETROFITTING
Acoustical planning principles can also be effectively applied to existing development, but the
aesthetic results are often unattractive. Establishing adequate rights-of-way or buffer zones is
difficult, typically including architectural barriers or walls. Capital construction and eventual
maintenance costs can become limiting factors.

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NOISE BARRIERS
A noise barrier (also called a sound wall, sound berm, sound barrier, or acoustical barrier) is an
exterior structure designed to protect inhabitants of sensitive land use areas from noise pollution.
Noise barriers are the most effective method of mitigating roadway, railway, and industrial noise
sources – other than cessation of the source activity or use of source controls.

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EARTH BERMS
A berm is a noise barrier constructed of earth, often landscaped, running along a highway to
protect adjacent land users from noise pollution. The careful design and situation of earth berms
can be an effective way of reducing noise from traffic or construction operations. Berms can either
be temporary or remain as a permanent feature of the landscape. The slope of a berm depends on
the type of surface treatment or maintenance involved. For instance, a mowed grass berm is easier
to maintain if graded to a slope of 1:3 or less.
Earth berms for noise
control.
Earth berms and walls
can help control wind
and noise . Plantings
can provide
psychologicalrelief
fromnoise and also
help to controlwind.

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Earth berms for noise
control.
Various types of
embankments can be
used to maximize
diffraction angles.

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BARRIER WALLS
Barrier walls are also noise barriers which help in reducing or eliminating unnecessary noises.
Height as a variable influencing the effectiveness
of a noise barrier.
Barriers should be placed to interrupt lines of sight.
Distance as a variable influencing the
effectivenessof a noise barrier.
Barriers should be placed to maximize the
diffraction angle.

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Continuity as a variable influencing
the effectivenessof a noise barrier.
Barriers should be solid rather than
perforated.
Length as a variable influencing the
effectivenessof a noise barrier.
Barriersshould extend beyond the
protected structureto minimize
sound diffraction around the ends of
the barrier.

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VEGETATION
The type of ground surface over which sound travels does have a substantial effect on sound
attenuation, particularly when traveling over large distances. Areas covered with grass or other
types of groundcover are more absorptive than hard, paved surfaces, which tend to reflect the
sound. Taller plantings, such as hedges or shallow screen plantings (even though they may
completely block the view of the noise source), will not significantly reduce actual noise levels.
However, dense plantings of trees with an understory of shrubs can result in a reduction of sound.
Vegetationas noise barrier.
Vegetation will not significantly reducesound levels unless plantings are dense or 30 m deep or greater.

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COMBINATION OF EARTH BERMS, BARRIER WALLS AND VEGETATION
The primary value of vegetation in connection with sound control in the landscape is for its
aesthetic and psychological appeal. Perhaps the most important value of planting is to make barrier
walls, berms, and other sound control devices seem less visually intrusive in the landscape. But
these noise barriers can also be used in combinations of each other.
Barrier wall or combinationof wall and berm.

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The apparent height of a wall.
A combination of vertical and horizontallines
in a wall (i .e., articulation and texture rather
than a monolithic mass) can reduce the
apparent height of the wall .
Coarse texturedwalls minimizereflective
glare and provide visual diversity along
highways.
Plantings can also be used to minimize glare
and enhance visualdiversity.

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BUILDING LAYOUT AND SITE SELECTION
Specially constructed noise barriers are expensive, but fortunately are not the only means available
for noise control. Other means available include:
1. The use of existing or proposed buildings to shield others that is more sensitive.
2. The use of natural or constructed landscape features (hills and valleys, earth berms, etc.).
3. The optimization of other site planning or design criteria.
DESIGN PRINCIPLES
The three most important criteria for noise barrier design are acoustic effectiveness, economic
feasibility, and visual attractiveness. Acoustic criteria include the site planning objectives, the
choice of barrier material, and the quality of construction. Economic criteria include the cost of
materials and labor, implementation ease, and operating and maintenance costs. Visual criteria
include environmentally acceptable alternatives for highway users as well as for the people who
live near the barriers.

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Visual diversity along highways.
Wall design and plantings can be composed to provide
interesting visualsequences.
Stepped-back wall.
A wall which steps back can open up the view for the
motoristand providepsychologicalrelief from feelings of
tight enclosure.

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SOUND CONTROL METHODS
The methods commonly used for sound attenuation (the reduction of intensity of outdoor sounds
before they reach the receiver) are:-
1. SOUND ABSORPTION
This method uses plants to entrap or absorb sound vibrations. It is the most commonly used,
particularly for large scale applications. Sound is absorbed by all parts of the plant such as
leaves, branches, twigs and wood. The rougher the bark the better it absorbs sound. Experts say
the best species for this will have many branches and thick, fleshy leaves with thin petioles (leaf
stem). These broadleaf species lose their effectiveness in the winter when deciduous.
Fortunately they leaf out for maximum advantage during the months when windows are open
and you're spending time outdoors. In warm climates many more broadleaf evergreens can be
used for sound absorption benefits all year around.

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2. SOUND DEFLECTION AND REFLECTION
This method causes the noise to be bounced away from the recipient and sometimes back
toward the source. The difference is based upon the density and rigidity of the barrier. Can
create attractive and effective partitions that may serve as a fence, but also double as sound
barriers. When sound waves strike a 5 or 6 foot masonry wall, it does not vibrate so the waves
are reflected back toward the source. The sound waves that are higher up will go right over the
wall. That's why the freeway is so loud when it runs between two masonry sound walls. It's also
why sound absorption plants are used in conjunction with walls to catch the higher level sound.
When sound waves strike a slightly flexible panel it will vibrate. This transforms sound waves
into other forms of energy, and also deflects them off in different directions. The more flexible
the material, the greater the deflection. Common materials for sound deflection barriers are
fiberglass and corrugated metal.

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3. SOUND REFRACTION
This little known effect occurs when noise is dissipated, diffused or dispersed by striking a rough
surface on any plain. It's easier to understand using a room of a house as an example. If it is
empty with a bare floor and walls, every sound bounces off the hard surfaces to magnify it or
even cause a slight echo as it bounces around. Add carpeting and the echo vanishes.
Outdoor surfaces coated in plants can have much the same effect. It's why freeway sound walls
are often planted with clinging vines such as Boston ivy or creeping fig. On the ground plain the
most powerful tool is lawn, due to its large area and excellent refraction ability.

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4. WHITE NOISE
This is a very different solution than the first three. It is designed to create sound that is
appealing to the human brain as a mask for undesirable noise. The most widely used method is
a fountain that makes loud splashes. A landscape where absorption, deflection or refraction
solutions are in place can help a smaller fountain become far more effective than you might
think.
Plants can also make white noise too, that is if chosen the right ones. Wind in pine needles
produces a distinctive sound. The rustle of stiff oak leaves or those of dry autumn ones can make
problem noise seem minimal. Quaking aspen and bamboo are also recommended for this. In
addition, these trees also attract birds and other wildlife that makes their own sounds further
masking noise.

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DESIGN APPLICATION
(CASE STUDY)
RECREATIONAL DEVELOPMENT
Acoustical site planning
(example problem).
In this example, the
noise-insensitivearea
(parking lot) is used as a
buffer zone between the
highway and the
recreational areas.

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RESIDENTIAL DEVELOPMENT
Acoustical site planning (example problem).
In this example, a greenbelt is used as a noise buffer between the major highway and the
proposed residential development.

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BIBLIOGRAPHY