When completing an online Hold Mail request, a confirmation page will be displayed with a confirmation number to verify your request has been accepted. Make sure you print out this page or copy down your confirmation number for future reference.
The tidal range is the vertical difference between the high tide and the succeeding low tide. Tides are the rise and fall of sea levels caused by the combined effects of the gravitational forces exerted by the Moon and the Sun and the rotation of the Earth.
Disadvantages of Tidal Barrages. 1  They change the movement of water into and out of estuaries, which can disrupt the life cycles of certain marine life. 2  They can prevent the movement of fish and other wildlife into and out of estuaries, which can disrupt spawning. 3  Turbines can kill wildlife that tries to swim through them.