A storm in 1770 breached the sea wall at Abu Qir, creating a seawater lake known as Lake Abu Qir. The salt waters were kept separate from Lake Mariout by the canal that allowed fresh water to travel from the Nile to Alexandria. As part of the Siege of Alexandria, on 13 March 1801, the British cut the canal, allowing a great rush of sea water from Lake Abu Qir into Lake Mariout.