As part of the eco-inclusivity of the development the
Westerpark Estate has one of the first custom-designed sustainable urban
drainage systems. Urban drainage is viewed not as a separate system in the
Netherlands, but the regional water boards (Waterschap in Dutch) demands local
government to provide a so-called "watertoets" (= water check,
although hydrological impact assessment would be a more accurate translation)
for every spatial development, as the effects of the proposed development have
to be compensated hydrologically. These water boards are a separate tier of
government independent from central and local government. They have their own
elections and also enforce their own laws and taxes.
A view across a remnant of the original rural landscape,
looking towards the railway tracks connecting Breda with Rotterdam and Antwerp.
The original landscape was a patchwork of small fields and meadows interlaced
with streams. One of these streams is still winding through the landscape here,
the other sections of this stream have been incorporated into the housing
estate of Westerpark.
Apartment blocks line the street that forms the old
edge of Tuinzicht and mark the outer edge of the former green belt that began
here. These flat buildings are new and have been used to up the number of
residents and create a denser central area in this suburban section of Breda.
Behind the middle-rise apartment blocks the Westertuin
-a small park- stretches towards the new ring road beyond. almost half is taken
up by a large artificial lake. This body of water acts as a buffer that stores
rainwater in case of torrential rains. An elevated esplanade on both sides acts
as an embankment to prevent flooding if the lake might overflow.
Directly adjacent to the park is a row of apartment
buildings. In front is a main road and a car parking facility (a seen on the
right). Here the residents overlook the park from their windows. At the back
these buildings look out over a large stretch of grass planted with trees. The
architecture is typical of the building period (1996-2001) with lots of angles
that are now possible with computer aided design.
A view across the artificial lake towards the east
with the apartment blocks on the edge of Tuinzigt clearly visible on the
horizon. The lake has great value for wildlife. This was intentional, the design
of this lake incorporates "nature friendly margins" planted with
reeds and other aquatic plants. These also help to keep the water clear.
The artificial lake at the heart of this neighbourhood
park combines nature and play. Some parts are inaccessible and are reserved for
wildlife. In other places the water has been made accessible , for instance by
this jetty (on the right), from where you can take to the water in a rowing
boat or a canoe.
From the artificial lake, which incorporates part of
an old streambed, the stream proceeds as a drainage canal, that is also used to
store water when it rains heavily. The two rows of trees on either side make it
a formal reference to urban canals. The loose vegetative margins however create
a rather more natural feel in keeping with the suburban surroundings. The
housing on either side has been built in long terraces.
Again the buildings have a style of architecture
typical for the period. These are more expensive mid-range houses for owner-occupants.
More interesting is the way this "canal" has been designed. Sloping
lawns and low gabion walls allow the water level to rise above the "normal
level" that is maintained by a small weir. The natural edges with reeds
provide a nice contrast with the adjacent lawns.
This prominent apartment block is situated at the end
of the "canal" in a bend of the stream. The stream is also widened
here to reflect the building, and increase the capacity for water retention (a
few centimetres over a large expanse of water can create more water storage
than more centimetres over a stream).
Like most housing estates in the Netherlands, through-traffic
is discouraged or even made impossible in the layout of the streets. For slow
traffic like pedestrians and cyclists the shortest route should be possible. From
the cycle path along the ring road this cycle path connects to a suburban
street making the street a dead end or close. Cyclists can have a quicker and
more convenient route. This is a simple way of stimulating cycling and walking.
In the northern half of this housing estate the soil
is higher and rainwater can more easily drain away into the soil. To aid this
large expanses of grass have been incorporated to allow for this. In this the wide
grassy verge planted with Himalayan birch trees.
In contrast the housing in the southern section of the
estate was planned on low-lying soil with many ditches. The ditches were filled-in
prior to development, so other means of infiltrating and draining away
rainwater falling on roofs and paved surfaces had to be provided. So here the
green areas are rougher, more natural looking. They also have an ecological
function and are maintained as flowering meadows. Mostly very common species of
flowering plant like this Tansy (Tanacetum vulgare), are growing in these
grasslands.
An example of a housing alley with apple trees planted
on either side in grass verges. The houses beyond are special as these are a
variation of the Mulhouse Quadrangle, a housing type typical of mining colonies
and pre-garden city factory housing.
Some plants thrive in the conditions created by the
urban drainage ditches that are dry for most of summer, but fill up with water
on occasion. In some places the actual gully can only be distinguished a s a
slight depression and a slightly differently coloured band of grass. A wooden
walkway lets pedestrians cross the gully even when it is full of water.
Another housing alley with at a right angle to it
another infiltration gully or ditch clearly visible as a band of yellow grass.
These infiltration gullies run in between the houses, often along the streets.
Rainwater falling onto the roofs and the paved areas is directed towards these
infiltration facilities. When the amount of rainfall is greater that the
infiltration capacity of the soil the gullies fill with water. Thus the water
can be stored here temporarily.
In some places the gullies are part of a wide public
green space plated with suitable trees. These willows (*Salix alba) don't mind
growing in wet soil, but can also withstand dryer conditions. o these trees are
ideal for a situation with strongly fluctuating (ground) water levels.
The old Emerweg (has been converted to a wide cycle
path, the new road has been built beyond. That way the pollarded willows ("knotwilgen"),
a common feature of Dutch polders, could be retained in situ. The agricultural
drainage ditch that ran along the former road has been widened and incorporated
into the sustainable urban drainage system of the Westerpark Estate.
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