bore

bore, inrush of water that advances upstream with a wavelike front, caused by the progress of incoming tide from a wide-mouthed bay into its narrower portion. The tidal movement tends to be retarded by friction as it reaches the shallower water and meets the river current; it therefore piles up and forms a low wall of water that moves upstream with considerable force and velocity as the tide continues to rise. In the mouth of the Amazon River a tidal bore known locally as the pororoca occurs every spring tide. It has a wall of water from 5 to 15 ft (1.5–4.6 m) high and advances at a speed of from 10 to 15 mi (16–24 km) per hr. The highest recorded bore (15 ft/4.6 m) is found in the Fuchun River near Hangzhou, China. Bores are found also in the Bay of Fundy, in Solway Firth, in the Severn, Seine, and Hugli rivers, and in Hangzhou Bay.

The Columbia Electronic Encyclopedia, 6th ed. Copyright © 2012, Columbia University Press. All rights reserved.

More on bore from Fact Monster:

  • Edwin Garrigues Boring - Boring, Edwin Garrigues Boring, Edwin Garrigues , 1886–1968, American psychologist, b. ...
  • boring mill - boring mill boring mill, machine tool used to increase the size of a hole previously made in a ...
  • Floyd M. Boring - Biography of Floyd M. Boring, Floyd Boring was a Secret Service agent who guarded five U.S. presidents, and protected President Truman from an assasination attempt in 195…
  • What does it mean? - immunity My sister seems to have an immunity to boredom— she is bored all day long. she never ...
  • bookworm - bookworm bookworm, popular name for the larvae of several beetles that bore through books, e.g., ...

See more Encyclopedia articles on: Geology and Oceanography