Mississippi River

River Facts• Begins 200 miles north of Minneapolis (Minnesota)

at Lake Itasca State Park.• Length: 2,352 miles Width: 20 ft at headwaters to 1

mile across Louisiana• Ends in Gulf of Mexico• 31 states & 2 Canadian provinces drain into the

Mississippi Rive.• Water discharged at a rate of 600,000 cubic ft. per

second.• Takes 90 days for water to travel from spring to Gulf• Carries 436,000 tons of sediment each day

Longest river? The Mississipi with 3733km

• NO, longest is Missouri River, • but taken together, they form the largest

river system in North America. • the length of the Missouri/Mississippi is 3,895 mi/6268 km long.

a length exceeded only by the Amazon and Nile rivers

10 states irrigated North to south• Source : Lake Itasca at 450 m above sea

level in northern Minnesota,• falls to 725 feet/220m just below Saint

Anthony Falls in Minneapolis• joined by the Illinois River and the

Missouri River at Saint Louis, and by the Ohio at Cairo, Illinois.

• The Arkansas River joins the Mississippi in the state of Arkansas.

• The Atchafalaya River in Louisiana is a major distributary or defluent of the Mississippi.

Watershed of the Mississipi river

The Land the River BuiltSouthern Louisiana was created by the Mississippi Rivercarrying rich alluvial soil from its huge, funnel-shapedwatershed and depositing it where the river meets the Gulfof Mexico.

Mississipi: a calamity river or midwest’s economical infrastructure

• Mark Twain wrote that if the Mississippi were a "little European river... it would just be a holiday job... to wall it, and pile it, and dike it, and tame it down, and boss it around... But this ain't that kind of a river”

• Still used as a major shipping route for agricultural products, coal, steel, and petroleum.

• On Mississipi, barges carry 20% of nation’s coal 33% of petroleum 50% of exported grains

Prevention of floodingUS army corps of engineers have attempted to

control flow with dams, locks, and levees• Levees or floodwall control rising stream level• Reservoirs on tributary stream store floodwater

for later releaseRemember:the Mississippi River Flood of 1993? It wasn't just the Mississippi

River flooding that wreaked havoc, it was that all those tributaries flooded as well! At one point, the volume of water flowing past St. Louis was eleven times the volume of Niagara Falls!!

The Mississippi DeltaThe southern Louisiana

landform is roughly triangular in shape and, thus, is called a delta.

From last time Mississipi moves Eastward

Rich delta soil and a mild climate makes southern Louisiana suited for sub-tropical food plants.

Louisiana WetlandsThe Mississippi delta is low-lying land comprising saltwatermarshes and slow-moving, meandering waterways calledbayous. Louisiana’s wetlands and the Gulf of Mexicosupport a wide variety of fish, shellfish, and amphibians,the region’s foundation protein foods.

New Orleans• New Orleans was founded in

1718 as port city, gateway to the Mississippi and, thus, the entire American heartland.

• Because of New Orleans commerce, Louisiana gained economic viability early in its history.

• Much of New Orleans is below sea level, protected from water by levees.

1931

• When river reaches a critical stage, the Bonne Carre spillway is opened to allow water to flow into Lake Pontchartrain.

• It has been opened 10 times.

1953

• If river continues to rise after the Bonne Carre’ spillway is opened, then the Morganza Spillway is opened.

• Only opened twice so far.

inadequate?

Storm surge of hurricane Katrina amplified by levees in the funnel (estimated 5.5-6m

2005 08 29 Hurricane Katrina• Katrina passes to the east of New Orleans • Creates 28 foot high storm surge on Mississippi Gulf Coast • 18 foot high storm surge in Lake Borgne flooding nearly all of the

populated portion of St. Bernard Parish.• 15 foot storm entering the Industrial Canal through and Lake

Pontchartrain overtops floodwalls, breaches levees on floodwalls on both sides of the Industrial Canal.

• 11 foot storm surge in Lake Pontchartrain enters 17th St. and London Avenue drainage canals.

• All levee breaches were on human made for navigation or drainage canals these levees and floodwalls that had been built by the U.S. Army Corps of

Engineers, some as recently as the mid- 1990s• Floods over 80% of the city and results in over 1500 deaths

Why New Orleans is Vulnerable To Hurricanes

Natural Causes • Location near Gulf of Mexico• Low elevation (near sea-level)• Subsidence - caused by compaction of river

deposited sediments• Erosion of inactive delta lobe• Sea-level rise due to global warming

Why New Orleans is Vulnerable To Hurricanes

Human-Related Causes • Levees on River prevent flooding, but deprive floodplain of sediment,• Navigation and Exploration Canals which brings water to City• Salt water get into the fresh water swamps and marshes, killing the fresh-

water vegetation which holds soil• oil and natural gas are extracted from sediment that once held the oil in the

pore spaces, compacts, resulting in subsidence.• Nutria are beaver-like animals imported South America 1900, eat marsh grass

and their roots. Without these grasses, storms erode the soil and turn land into water

• Population expanding into lower lying areas • Inadequate, poorly designed, & incomplete hurricane protection system

Dont’t forget wildlife in Mississipi delta

• Endangered species: louisiana black bear, green sea turtle,• Plants: Cypress trees that we’ve seen• Fishes, shellfishes• Migratory Birds: snow gooses, white egrets• Reptiles: américan alligators that we’ve seen closely• Today, Coastal Louisiana is losing 24 square miles of

wetlands each year — roughly equivalent to a football field every 30 minutes!!!

• Dr Amanda Staudt point of view: https://www.youtube.com/watch?v=tqM4-dHSjSU&feature=player_embedded

Infortunatly I haven’t seen

At Home now: delta of the Rhône

• At Home now: delta of the Rhône is divided into two arms, the Grand Rhône and the Petit Rhône, shortly before Arles. It forms a delta, the Camargue, and flowss into the Mediterranean.

•The Development of the Rhône Valley has been led by the Compagnie Nationale du Rhône (CNR), staggered from the 1930s, which included the construction of dams, pipelines, electric management program, irrigation, road construction and industrial equipment

It’s easy

Marseille ou la Nouvelle Orléans

7mn de bonheur bien gagnés…

• https://www.youtube.com/watch?v=wi0cLdJCgTA