Page "Slack water" Paragraph 4

Slack water is a much misused term, often used to describe a period of equilibrium between two opposing streams when the water is anything but slack, but highly stressed.

Although there may be no flow in either direction there may be many eddies, and since this so-called slack water occurs before high water while the tide is still rising, the tide may continue to rise even after the direction of the stream has reversed.

Conversely, since it occurs after low water while the tide is rising, the tide may also continue to rise during this so-called low water slack period.

Such conditions typically occur at river mouths, or in straits open at both ends where their entrances have markedly different physical characteristics.

Examples include The Rip between Point Nepean and Point Lonsdale at the entrance to Port Philip Bay, Victoria, Australia ; the Menai Strait between Anglesey and Wales ; or the Strait of Gibraltar at the entrance to the Mediterranean Sea.