The Inundation of Walcheren was the intentional, but uncontrolled military inundation, effected by bombing the sea dikes of the former island of Walcheren in Zeeland by the Allies on and after 3 October 1944 in the context of Operation Infatuate during the Battle of the Scheldt after the Allied Invasion of Normandy during World War II. Though the inundation was justified by military necessity, it is controversial whether it was proportional in view of the predictable devastating effects for the civilian population, and the ecology of the island. The fact that the breaches in the sea dikes of the island remained open for a very long time, subjecting the island to the full impact of the twice-daily tides, caused severe damage to agricultural land and infrastructure, and severe hardship for the civilian population. Leaving the breaches open for such a long time, which was unavoidable due to the war-time lack of resources making closing impossible, subjected them to scouring by the tides, that widened and deepened them to such an extent that closing them eventually became extremely difficult, necessitating the development of new dike-building techniques, such as the use of caissons. The last breach was closed on 23 October 1945 and the draining of the island took until early 1946. Only after that could rebuilding the infrastructure and reconstructing the housing stock and the island's economy start. Walcheren was spared during the North Sea Flood of 1953 that devastated many other parts of Zeeland.

A flood is an overflow of water that submerges land that is usually dry. In the sense of "flowing water", the word may also be applied to the inflow of the tide. Floods are of significant concern in agriculture, civil engineering and public health. Human changes to the environment often increase the intensity and frequency of flooding. Examples for human changes are land use changes such as deforestation and removal of wetlands, changes in waterway course or flood controls such as with levees. Global environmental issues also influence causes of floods, namely climate change which causes an intensification of the water cycle and sea level rise. For example, climate change makes extreme weather events more frequent and stronger. This leads to more intense floods and increased flood risk.