When the British opened the lake to the sea in Napoleon's time it caused a salt-water flood that destroyed 150 villages.[1] The cutting of the dykes by the British in 1801 refilled Lake Mariout so that it suddenly regained its ancient area, became filled with salt water instead of the former fresh, and was too shallow for navigation. Alexandria's access to the Nile was lost, necessitating the opening of the Mahmoudiyah Canal from Alexandria to the Nile in 1820.[6]