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:
“Never before has a civilization reached such a degree of a contempt for life; never before has a generation, drowned in mortification, felt such a rage to live.”
—Raoul Vaneigem (b. 1934)
“The name of the town isn’t important. It’s the one that’s just twenty-eight minutes from the big city. Twenty-three if you catch the morning express. It’s on a river and it’s got houses and stores and churches. And a main street. Nothing fancy like Broadway or Market, just plain Broadway. Drug, dry good, shoes. Those horrible little chain stores that breed like rabbits.”
—Joseph L. Mankiewicz (1909–1993)
“I see an America whose rivers and valleys and lakes, hills and streams and plains; the mountains over our land and nature’s wealth deep under the earth, are protected as the rightful heritage of all the people.”
—Franklin D. Roosevelt (1882–1945)