Drowned River Valleys
Many drowned river valley estuaries were formed between about 15,000 and 6000 years ago following the end of the Wisconsin (or 'Devensian') glaciation when a eustatic rise in sea level of 100 to 130 m (330 to 430 ft) flooded river valleys that were cut into the landscape when sea level was lower, creating the estuarine systems. Additionally, the general subsidence of coastal regions contributed to the development. Well-developed drowned river valleys are generally found on coastlines with low, wide coastal plains. Their width-to-depth ratio is typically large, appearing wedge-shaped in the inner part and broadening and deepening seaward. Water depths rarely exceed 30 m (98 ft). Examples of this type of estuary include the Hudson River, Chesapeake Bay, and Delaware Bay along the U.S. Mid-Atlantic coast; and along the U.S. Gulf coast, Galveston Bay and Tampa Bay.
Read more about this topic: Estuary, Classification Based On Geomorphology
Famous quotes containing the words drowned, river and/or valleys:
“I will venture to affirm, that the three seasons wherein our corn has miscarried did no more contribute to our present misery, than one spoonful of water thrown upon a rat already drowned would contribute to his death; and that the present plentiful harvest, although it should be followed by a dozen ensuing, would no more restore us, than it would the rat aforesaid to put him near the fire, which might indeed warm his fur-coat, but never bring him back to life.”
—Jonathan Swift (1667–1745)
“The river knows the way to the sea;
Without a pilot it runs and falls,
Blessing all lands with its charity.”
—Ralph Waldo Emerson (1803–1882)
“But oh, not the hills of Habersham,
And oh, not the valleys of Hall
Avail: I am fain for to water the plain.
Downward, the voices of Duty call—
Downward, to toil and be mixed with the main,
The dry fields burn, and the mills are to turn,
And a myriad flowers mortally yearn,
And the lordly main from beyond the plain
Calls o’er the hills of Habersham,
Calls through the valleys of Hall.”
—Sidney Lanier (1842–1881)