Western Europe

During the first year of the Great Roman Civil War, Julius Caesar’s troops lay siege to the walled city of Massilia (modern-day Marseille, France) using siege towers, battering rams, and by digging “mines” or tunnels to undermine the city walls. Massilians defend their city with “dogged determination;” tactics included directing water through pipes to wash down on attackers, which the Romans counter by covering siege buildings with bricks and “several coatings of stucco.” Defenders also excavate a large basin inside…

Napoleon orders the construction of a canal between Neuss and Venlo, to connect the Rhine and Meuse rivers, to divert trade from the Batavia Republic to the Southern Netherlands, then under French control. Three-quarters of the canal are completed, but work stops because of lack of funds.

Louis XIV starts the third of the Dutch Wars in 1672, in which the French overrun the Netherlands. In defense, the Dutch open their dikes and flood the country, creating a watery barrier that is virtually impenetrable.

The Spanish Habsburgs attempt to prevent ship traffic on the River Rhine from reaching the Dutch Republic in order to damage the Dutch economy. Plans are also made to divert water from the Rhine to lands under Spanish control, to dry up downstream cities in Holland. The first stage is a canal between the Rhine and Meuse, between the cities of Rheinberg and Venlo. Plans for a later stage call for a connection between the Meuse and the Scheldt to…

In 1573 at the beginning of the eighty years war against Spain, the Dutch flood the land to break the siege of Spanish troops on the town Alkmaar. The same defense is used to protect Leiden in 1574. This strategy becomes known as the Dutch Water Line and is used frequently for defense in later years.

During the mobilization of the Dutch at the beginning of World War II, 1939-40, the Dutch attempt to flood the Gelderse Vallei with the New Dutch Water Defence Line, which had been completed in 1885. During the German invasion in May 1940, large areas are inundated.

Germans flood the Ay River in France in July 1944, creating a lake two meters deep and several kilometers wide, slowing an advance on Saint-L?, a German communications center in Normandy.

Germans flood the Ill River Valley during the Battle of the Bulge (winter 1944-45) creating a lake 16 kilometers long, 3-6 kilometers wide, and 1-2 meters deep, greatly delaying the American Army’s advance toward the Rhine.