The geography of the mississippi river
Mississippi river history
The channel project was complete when the Moline Lock, which bypassed the Rock Island Rapids, opened in A major flood in caused it to overtake the lower 10 miles of the Kaskaskia River, forming a new Mississippi channel and cutting off the town from the rest of the state. Built by a private power company to generate electricity, the Keokuk dam was one of the largest hydro-electric plants in the world at the time. The retention time from Lake Itasca to the Gulf is typically about 90 days. Four great earthquakes in and , estimated at approximately 8 on the Richter magnitude scale , had tremendous local effects in the then sparsely settled area, and were felt in many other places in the Midwestern and eastern U. Environmental concerns The Upper Mississippi River has naturally maintained equilibrium between its channel and backwater areas since the last glacial retreat. Mississippians continually depend on, adapt to, or modify their natural settings in ways that reveal who they are, politically, economically, technologically, and culturally. There are smaller numbers of Hindus, Jews, and Muslims. The Mississippi also comprises several natural lakes such as Lake Pepin. On average the Mississippi has only one-eleventh the flow of the Amazon River, but is nearly twice that of the Columbia River and almost six times the volume of the Colorado River. The main channel has been locked into one position, preventing it from meandering and creating new aquatic areas. The reduction in sediment transported down the Mississippi River is the result of engineering modification of the Mississippi, Missouri, and Ohio rivers and their tributaries by dams, meander cutoffs , river-training structures, and bank revetments and soil erosion control programs in the areas drained by them.
As the temporary rivers formed during this ice age found outlets in other bodies of water, they left a depression with sediments indicating to this ice era. It is also one of the world's most important commercial waterways and one of North America's great migration routes for both birds and fishes.
How much more isolated the area would have been in its formative years without these natural features.
The Mississippi River drains an area of about 3. It takes about three months for water that leaves Lake Itasca, the river's source, to reach the Gulf of Mexico.
The channel project was complete when the Moline Lock, which bypassed the Rock Island Rapids, opened in The Mississippi River lies entirely within the United States.
Mississippi river map
It was thought that the river's velocity would scour off bottom sediments, deepening the river and decreasing the possibility of flooding. The reduction in sediment transported down the Mississippi River is the result of engineering modification of the Mississippi, Missouri, and Ohio rivers and their tributaries by dams, meander cutoffs , river-training structures, and bank revetments and soil erosion control programs in the areas drained by them. On a side note, it is at this area of the Mississippi River that the river flows East to West as opposed to its normal course North to South. DDT, a chemical used in fertilizers was a dangerous pollutant. In , Hurricane Katrina destroyed , acres of wetland habitat. The reported length of a river may increase or decrease as deposition or erosion occurs at its delta, or as meanders are created or cutoff. Watershed Size Some like to measure the size of a river is by the size of its watershed, which is the area drained by a river and its tributaries. At Lake Itasca, it would take 10 minutes for one semi-trailer of water to flow out of the lake into the Mississippi. Flora natural vegetation consists of forests oak, hickory, cypress, and pine , grasslands, and salt grass marshes. Water Supply Communities up and down the river use the Mississippi to obtain freshwater and to discharge their industrial and municipal waste. To move goods up and down the Mississippi, the U. Anthony Falls.
Volume Another way to measure the size of a river is by the amount of water it discharges.
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