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:
“By heaven, methinks it were an easy leap
To pluck bright honor from the pale-faced moon,
Or dive into the bottom of the deep,
Where fathom-line could never touch the ground,
And pluck up drowned honor by the locks.”
—William Shakespeare (1564–1616)
“If a walker is indeed an individualist there is nowhere he can’t go at dawn and not many places he can’t go at noon. But just as it demeans life to live alongside a great river you can no longer swim in or drink from, to be crowded into safer areas and hours takes much of the gloss off walking—one sport you shouldn’t have to reserve a time and a court for.”
—Edward Hoagland (b. 1932)
“I do like a little romance ... just a sniff, as I call it, of the rocks and valleys.... Of course, bread-and-cheese is the real thing. The rocks and valleys are no good at all, if you haven’t got that.”
—Anthony Trollope (1815–1882)