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:
“The sea called
you faced the estuary,
you were drowned as the tide passed.
I am glad of this
at least you have escaped.”
—Hilda Doolittle (1886–1961)
“The Xanthus or Scamander is not a mere dry channel and bed of a mountain torrent, but fed by the ever-flowing springs of fame ... and I trust that I may be allowed to associate our muddy but much abused Concord River with the most famous in history.”
—Henry David Thoreau (1817–1862)
“It was a comfort in those succeeding days to sit up and contemplate the majestic panorama of mountains and valleys spread out below us and eat ham and hard boiled eggs while our spiritual natures reveled alternately in rainbows, thunderstorms, and peerless sunsets. Nothing helps scenery like ham and eggs.”
—Mark Twain [Samuel Langhorne Clemens] (1835–1910)