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09 - Green noise barriers in Hoogeind, Breda, Netherlands |
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Project name
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Roads as
Ecosystems
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Fig. 1: Noise
barrier landscape Hoogeind, east of Breda in The Netherlands. Photo:
Breda West |
Keywords
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Design
and construction of roads should not only look at a better inserting into the
visual-landscape or aesthetically fine. The design and construction should
also realize more coupling of different ecosystem functions. An ecosystem
approach is very helpful whereby the following aspects become part of the
integral ecological design:
- Improvement of biological
diversity
- Prevention, mitigation and
compensation of negative effects, like habitat fragmentation,
disturbance, water and air pollution, disruption of hydrological
processes.
Beside
the ecosystem approach the symbiotic relationship between culture, nature and
design is useful, especially if art is also included.
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Start of
the project
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1995;
fully realized in 1998
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End of
the project
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Still
existing
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Contact
person
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www.gemeentebreda.nl
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Short project description/ project function
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Along the
motorway A58, east of the town Breda in the province of Noord-Brabant in The
Netherlands, an integrated noise barrier landscape was created, which
functions as an ecosystem.
The combination of functions consists of: large
earth berms as noise barriers, gabions (large meshed netting cages filled with stones) are positioned
on the slopes towards the motorway like a fortification (giving attention to
Breda's history as a fortified town), water retention, constructed wetlands
for the purification of a polluted stream and cleaning of road run-off water,
joint recreational use, nature development, anti-acidification measures by
filling the gabions with limestone instead of basalt to increase by seepage
water the pH of the lower lying grasslands.
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Summary of experiences
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The
vegetation formed by seeding (hydro-seeding) indigenous plants forms a natural outlook. After some
years interesting animal species can be found here (reed warbler, wood mice,
buzzard, partridges).
Although
a full integral approach has been chosen, it is a pity that the culvert
under the motorway A58 has not been adapted for more faunal use, because at
the other side of the motorway nature development is taken place on a new
industrial area, which had another planning time scale.
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Project
benefits
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A
combination of functions was realized giving attention to Breda's
history, water retention and cleaning possibilities by helophyte filter
system, joint recreational use, nature development and appreciation not only
from the car drivers but also for the people living nearby (behind the large
earth berms).
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Project level
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Mature technology
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Financial scale
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Construction
costs: Costs consisting of earth for the noise barrier, which came available
due to road construction. Further costs consists of gabions, and
restructuring the small valley with the stream.
Maintenance
costs: Mowing of the grasslands once a year and maintenance of the terraces
consisting of the gabion may become more difficult in future as maintenance
were not fully taken into account in the design.
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Environmental conditions
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The
motorway crosses a small lower lying valley with a small stream surrounded by
marshy peatland formed by seepage, due to a false groundwater level on top of
a clay-like sediment, which gives high potential for nature development.
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Altitude
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20 m
above sea level
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Description of special local conditions
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Due to a
reconstruction of a number of motorway exit roads (closure and redesign)
enough soil became available to build the earth walls as noise barrier.
Hydro-seeding
has been successfully used to sow indigenous grasses and other higher plants
which prefer low nutrient levels.
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Why this is ecological engineering
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The many
functions described have been brought together in a limited area, which has
led to a greater usefulness and higher ecological value. The constructed noise barrier
landscape is visually nice to see, shows cultural aspects and is sustainable
in the long run, so serving human as well as natural values.
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Last Updated ( Tuesday, 18 December 2007 )
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