Navigable
aqueducts (sometimes called water bridges) are bridge structures that
carry navigable waterway canals over other rivers, valleys, railways or
roads. They are primarily distinguished by their size, carrying a larger
cross-section of water than most water-supply aqueducts. Although Roman
aqueducts were sometimes used for transport, aqueducts were not
generally used until the 17th century when the problems of summit level
canals had been solved and modern canal systems started to appear.
01. Pontcysyllte Aqueduct — UK
Photo — Link
The Pontcysyllte Aqueduct is a
navigable aqueduct that carries the Llangollen Canal over the valley of
the River Dee in Wrexham County Borough in north east Wales. Completed
in 1805, it is the longest and highest aqueduct in Britain, a Grade I
Listed Building and a World Heritage Site. Built by Thomas Telford and
William Jessop, it is 307 m. (1,007 ft.) long, 3.4 m. (11 ft.) wide and
1.6 m. (5.25 ft.) deep.
Photo — Link
The towpath is mounted above the
water, with the inner edge carried on cast-iron pillars in the trough.
This arrangement allows the water displaced by the passage of a narrow
boat to flow easily around it, enabling relatively free passage. Every
five years the ends of the aqueduct are closed and a plug in one of the
highest spans is opened to drain the canal water into the River Dee
below, for inspection and maintenance of the trough. [Link - Map]
02. Håverud Aqueduct — Sweden
Photo — Link
Håverud
Aqueduct is regarded as one of the greatest engineering achievements of
its day. In the mid eighteen sixties it became clear that this section
of the Dalsland Canal could not be completed using a traditional lock
owing to local soil conditions. As a consequence a thirty metre long
metal chute was constructed that traversed the Dalsland Waterfall.
Photo — Link
Today the aqueduct is a tourist
attraction and is a unique meeting point of waterway, road and railway.
There is a popular visitor centre here. This is the starting point for
many boat trips on the Dalsland Canal. [Link Map]
03. Magdeburg Water Bridge — Germany
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The Germans took over 80 years to
build this 918m (3,000 ft) bridge over the Elbe river near the town of
Magdeburg. Canal engineers had first conceived of joining the two
waterways as far back as 1919, and by 1938 the Rothensee boat lift and
bridge anchors were in place, but construction was postponed during
World War II. After the Cold War split Germany, the project was put on
hold indefinitely by the East German government.
Photo — Link
With the reunification of Germany
and major establishment of water transport routes made the Water Bridge
a priority again. Work started in 1997, with construction taking six
years and costing €500 million. The water bridge now connects Berlin’s
inland harbour network with the ports along the Rhine river. The
aqueduct's trough structure incorporates 24,000 tonnes of steel and
68,000 cubic meters of concrete. The Magdeburg water bridge was opened
in 2003. [Link Map]
04. Aqueduct Ringvaart Haarlemmermeer — Netherlands
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Near Roelofarendsveen (a town in
western Netherlands), the Ringvaart Channel crosses the A4 Highway by
means of an aqueduct. It was built in 1961, making it the oldest
aqueduct in the Netherlands. In 2006, construction was completed of two
new portions: on the east side for crossing new north-bound lanes for
the expanded highway; and on the west side for the new HSL-Zuid
high-speed railway. The new aqueduct is 1.8 kilometres (1.1 mi) long. [Link Map]
05. Pont du Sart Aqueduct — Belgium
Photo — Link
The Pont du Sart Aqueduct is a
navigable aqueduct that carries the Centrumkanaal (channel in western
Belgium) over the crossroads between N55 and N535 road near the town of
Houdeng-Goegnies.
Photo — Link
This concrete building is 498
meters (1,600 ft) long and 46 meters (150 ft) wide. Pont du Sart
Aqueduct weighs 65,000 tons and is supported by 28 concrete columns,
three meters (10 ft) in diameter. [Link Map]
06. Aqueduct Veluwemeer — Netherlands
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Veluwemeer is aqueduct on the
N302 road near the small town of Harderwijk in the Eastern Netherlands.
It is located under a small part of the lake Veluwemeer and at the same
time connects the mainland Netherlands to Flevoland (largest artificial
island in the world).
Photo — Link
Veluwemeer is 25 meters (80 ft)
long and under it daily passes about 28 000 vehicles. The aqueduct was
opened to traffic in 2002. [Link Map]
07. Briare Aqueduct — France
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The
Briare Aqueduct carries the Canal latéral à la Loire over the River
Loire on its journey to the River Seine in France. It replaced a
river-level crossing from the canal to meet the Briare Canal that was
hazardous in times of flood. Between 1896 and 2003 it was the longest
navigable aqueduct in the World until the opening of the Magdeburg Water
Bridge.
Photo — Link
The aqueduct is built on fourteen
piers. These piers support a single steel beam in turn supporting a
steel channel which contains more than 13,000 tonnes of water, 2.2
meters (7 ft) deep and 6 metres (20 ft) wide allowing boats with a 1.8m
draught to cross. The width of the aqueduct, towpaths included, is 11.5
meters (38 ft) and its length is 662.7 meters (2.175 ft). [Link Map]
08. Naviduct Krabbersgat — Netherlands
Photo — Link
The Krabbersgat-locks in the
Netherlands is the first “Naviduct” in the world. This unique mega
project, consisting of a ship-lock with an underpass for road traffic,
was conceived to ease bottlenecks for both vehicle and sea faring
traffic.
Photo — Link
The massive structure is 125
meters (410 ft) in length and 25 meters (82 ft) wide. 1,450 m3 of earth
was removed to accommodate 20,000 m3 of concrete. This naviduct in
Enkhuizen was opened in 2003. [Link Map]
09. Edstone Aqueduct — UK
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Edstone Aqueduct is one of three
aqueducts on a 4 miles (6 km) length of the Stratford-upon-Avon Canal in
Warwickshire. All are unusual in that the towpaths are at the level of
the canal bottom. At 475 feet (145 m), Edstone is the longest aqueduct
in England. It crosses a minor road, the Birmingham and North
Warwickshire railway and also the trackbed of the former Alcester
Railway. [Link Map]
10. Aqueduct Langdeel — Netherlands
Photo — Link
Aqueduct Langdeel is located on
the N31 highway, near the city of Leeuwarden in the northern
Netherlands. The aqueduct carries the canal of the same name.
Photo — Link
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