It was not till 1867, on the occasion of the Universal Exhibition,
that a dam was constructed at Suresnes that permitted of omnibus-boat
service. The effect that this dam had was to raise the water 7½ feet up
stream, and to consequently suppress the natural incline of the river
between Paris and Suresnes. Its action made itself felt as far as to
the Austerlitz Bridge in front of the Garden of Plants.
Between Suresnes and Lavallois the Seine is divided into two arms
that are separated by the isles of Puteaux and Grande-Jabbe. The left
arm was dammed at Suresnes, and here was established the sluice that
allowed boats to cross the falls. The right arm was dammed at Levallois.
A law of April 6, 1878, decided the increase of the depth of the Seine
between Paris and Rouen in order to allow boats of a draught of ten
feet to reach Paris, and to bring thither, without transfer, English
coal and Bordeaux wines. The Consul-General of the Seine having offered
to contribute toward the expense, on condition that such boats might
have it in their power to ascend as far as to Bercy, a law of July 21,
1880, decided that the Suresnes dam should be raised about three feet
in order to increase the anchorage. To effect this, the dams of 1867
were entirely rebuilt, the new ones being located at Suresnes, across
the two arms of the river. At the same time, the existing sluice was
doubled by another one that was larger and deeper.
This great work was executed under the able direction of Mr. Boule,
engineer in chief of roads and bridges, who has in charge the
navigation of the Seine, outside of Paris, between Montereau and
Poissy. The new sluice was constructed in 1880 and 1881, the dam to the
left and the intermediate weir in 1882 and 1883, and the pass to the
right in 1884. The width of the Seine at this point is about 820 feet,
the length of the passes varies between 209 and 236 feet, and the two
sluices occupy a width of 98 feet.
In the construction of the three passes there were established, up and
down stream, dikes about 325 feet apart, thus giving considerable space
for the installation of work yards, and much facilitating operations.
The new dam is closed by movable mechanisms of the kind invented by
Engineer Poiret in 1834. The iron trestles that support the wickets are
the largest that have ever been constructed, their height being nearly
20 feet and their weight 3,950 pounds. During freshets they are laid
upon the bed of the sluice, and when the water subsides they are raised
vertically. Upon these supports are placed swinging wickets, like those
of mills, according to a system devised by Mr. Boulet in 1874, and
which has been tried since then with success at the Port-a-l'Anglais
dam near Paris. This system has likewise been successfully applied upon
the Moskowa, below Moscow, and upon the Saone, at the Mulatiere dam,
near Lyons.[9]
[9] See SUPPLEMENT No. 264 for an illustrated description.
The construction of the new sluice presented great difficulties,
by reason of the fact that it was necessary to avoid obstructing
navigation in the existing sluice, where the boats stood thirteen or
fifteen feet above the laborers who were working at the side, behind
simple dikes. Yet it became necessary to forbid the passage of the
sluices for nearly a month each year. At Suresnes this was taken
advantage of each time to keep the works in full blast during the
whole night, the lighting being done by electricity. During these
interruptions the boats accumulated at the sides of the dam, and gave
the public an idea of what Paris would be as a sea port.
All the work is now finished. Its estimated cost is six millions, two
of which were devoted to the construction of about half a mile of dock
wall and of a long and wide sewer.
The sluices were opened for navigation on the 15th of September last.
The new dams will be in operation in 1885, and next summer they will
increase the height of water in Paris by one meter.--_L'Illustration_.
[Illustration: IMPROVEMENT OF THE RIVER SEINE.--THE NEW DAM AT
SURESNES.]