Mississippi River（English: Mississippi River) is the largest river in the United StatesNorth AmericaThe longest river is the fourth longest river in the world.
If theLake Itasca The upper Mississippi River is the source of the river, with a total length of 3767km.yesNorth AmericaThe longest processDrainage areaThe widest and largest river is located in south central North America.The average annual sediment discharge of the river is 495 million tons.The river basin is among the three largest in the worldblack soilOne of the zones.Usually originated in the western United StatesThe Rocky MountainsOfthe missouriThe tributary Red Rock (located atMontana）As the source of the river, the total length is 6021km, ranking fourth in the world;The drainage area is 3.22 million km2, accounting for 41% of the total area of the United States, covering the eastern and central regions.The average annual runoff of the estuary is 580 billion m3 (includingAtchafalaya River ）。The average annual sediment discharge is 312 million tons.
If it originated fromThe Rocky MountainsThe largest tributary in the eastthe missouriIt is 6020 kilometers long, ranking fourth in the world.Basin starts from the northThe Great LakesNearbyLake Itasca , NandaGulf of Mexico, eastAppalachian Mountains, west toThe Rocky Mountains, with a drainage area of 3.22 million km2, accounting for aboutNorth America1/8 of the area.There are more than 250 tributaries in total. The tributaries on the west bank are more and longer than those on the east bank, forming a huge asymmetric dendritic water system.The water is abundant, and the annual average flow near the estuary reaches 18800 m3/s.
The Mississippi River isNorth AmericaThe crown of the river, together with its main tributariesDrainage areaCalculation, second only to South AmericaAmazonRivers and AfricaCongo River, ranking the third in the world in terms of drainage area (about 3.1 million km2).As the main artery of the central river in highly industrialized countries, the Mississippi River has become one of the busiest commercial waterways in the world.This once unruly river flows throughNorth AmericaSome of the most fertile farmland in the mainland has now been controlled and utilized by human beings.The Mississippi River has two side branches -- the Ohio River in the east and the Ohio River in the westthe missouri。[1]
Water system composition
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Introduction to water system
Mississippi River Basin Map
River source section from river source toMinnesotaOfSao PauloNavigation starting point.The river is cool and quiet, winding through the rural lowlands with many lakes and marshes.Upstream from Sao Paulo to MissouriSaint LouisNear the mouth of the Missouri River.This section flows through limestone cliffs and passes through Minnesota, Wisconsin, Illinois andIowaAbsorb the rivers and streams on both banks.It is in this reach that Algonquian speakersIndianIt is called the "father of the river".The middle section is 322km long from the confluence of Missouri River to the Ohio Estuary.The Missouri River is fast flowing and muddy, especially in the flood period, which not only increases the flow of the clear Mississippi River, but also inputs a lot of sediment.The Ohio RiverIllinoisWhen Cairo flows in, it is the lower reaches of the Mississippi River, which is full of water,river courseIt is wide, and the distance between the two sides is often 2.4 kilometers, forming a brown torrent that slowly runs towards the Gulf of Mexico.
There are many tributaries of the Mississippi River, 54 of which are more importantClimatic geomorphologyThe similarities and differences of the conditions make the hydrological characteristics of the tributaries on the east and west sides completely different.The main tributaries are Ohio River, Missouri River, Arkansas River, Red River andTennessee RiverEtc.These tributaries are distributed in the whole basin like dense branches on a big tree.[1]
Flow area
Mississippi Delta
If the length of Missouri Jefferson (Redrock) water system is added to the Mississippi River after the confluence of Missouri and Mississippi, the total length is 5971 kilometers, ranking fourth in the world.However, the main trunk of the Mississippi River is 3780 kilometers long, ranking only 20th in the world.The Mississippi River flows about 17000 m3/s (600000 cubic feet/s), ranking the 8th in the world.The Mississippi River basin is very wide, and many tributaries are connected with most of the United StatesEconomic region。The main stream of the Mississippi River flows through 10 states in total:Minnesota、Wisconsin、Iowa、Illinois、Missouri、Kentucky、Tennessee、Arkansas、Mississippi、Louisiana。The whole water system flows through 31 of the 48 states in the United States and two states in Canada.The last half of the lake that the Wisconsin River flows through isWisconsin, half inMichigan。[2]
River reach division
Headwater of river
Mississippi River Basin
The Mississippi River itself originates near Lake Etaska in northern Minnesota and flows southward into the Gulf of Mexico, with a total length of 3950 kilometers.The upstream of this main stream is developed on the ancient rock surface, where has undergone intense ice erosion, so the soil is very thin, and the river bank is often exposed with hard rocks, which makes the scenery beautiful.There are tens of thousands of scattered lakes in Minnesota.These large and small lakes are like naturereservoirIt also plays an important role in regulating the water supply of the Mississippi River.The most representative of them is the Missouri River.
The mainstream of the Missouri River originates from the Rocky Mountains in the northwest of the United StatesYellowstone National ParkNearby.The other tributary originates from the border area between Canada and the United States. The river has small water volume, large sediment concentration and large annual variation of water level.The average annual flow of the Missouri River is about 2000 cubic meters per second, but the maximum flow in the early summer flood period can reach 22640 cubic meters per second, while in the winter dry season,Minimum flowOnly 120 cubic meters per second.Especially after the heavy rain, the muddy water flows into the Mississippi River like a muddy flow. Even within more than 100 kilometers below the Missouri estuary, the muddy Missouri River can be distinguished from the clear Mississippi River.Therefore, for people living on the banks of Missouri River, the river water can neither be drunk nor cultivatedAgricultural irrigationAnd shipping.
upper reaches
Mississippi Delta
Source: Lake Etaska toMinneapolisAnd St. Paulupper reaches。The upper reaches of the Mississippi River also include the main stream above the mouth of the Missouri River, the largest tributary of the Mississippi River, which actually includes the entire Missouri River basin and the upper reaches of the Mississippi River itself, with a total length of more than 4300 kilometers.It first flows through the Rocky Mountains. Rivers divide the mountains. With complex water systems and braided tributaries, it forms many beautiful canyons.Flow throughGreat FallsIn the nearby section, in the process of only 16 kilometers long, the drop is 187 meters, forming the famousSan Antonio Falls。From Milke Estuary toSuzhou City, passing through Missouri hilly plateau, the river valley is still deep and narrow.The river enters below SuzhouPlain areaThe riverbed becomes curved and vast marshes are formed on both banks.The water and soil loss in this area is relatively serious, and the water source of the basin is mainly supplied by mountain snow water.The sediment content is second to none in the mainstream and tributaries of the Mississippi River basin, with an average annual sediment concentration of more than 310 million tons, accounting for about 75% of the total annual sediment input into the ocean by the Mississippi River.So in the past, Americans called the Missouri River "a raging big muddy river".From Lake Itaska to the mouth of Missouri River, the main stream of Mississippi River also belongs to the upper reaches.The river flows out from Lake Itaska, windingIn the forestAnd swamp, where the water flow is slow, which is totally different from the scene of rapid flow in the upper reaches of ordinary rivers.Near the source of the river, there are many lakes.On this stretch of the river lies the youngest big city in the north central United States, the "Twin Cities", also known as the "City of Thousands of Lakes".As it is located at the junction of spring wheat and cheese belt, combined with the rich water resources of the Mississippi River, the city has become one of the important light industry centers in the United States, and a large manufacturing center of commerce, finance, electronics, agricultural machinery and transportation machinery in the north central United States.It is also an important maple producing area in the United States.Maple trees can not only green the land and beautify the environment, but also extract maple sugar. The wood can be used for furniture or construction.In the red leaf picking season every year, many people come here to watch and collect, which has been developed intoTourist area。
middle reaches
The middle reaches of the Mississippi River is relatively short, generally from the confluence of the Missouri River and the Mississippi River to the mouth of the Ohio River
Mississippi River
The total length is 320 kilometers.Mainly including if the two sides have successively remittedChipova River、Wisconsin River、Des Moines、Illinois River、the missouriandOhio RiverThe total length can reach 1373 kilometers.The river section north of St. Louis has large riverbed slope and many rapids and rapids;Near St. Louis and to the south, the riverbed gradient decreases and the river valley widens.From Cape Girard to the lower corner, the curvature of the river is significantly increased, the valley is open, and the river at the Ohio estuary is 2.4 kilometers wide.In Missouri andIllinoisIn some areas, it is warm and rainy all the year round. The crops grow well and the water flow is stable,channelIt is deep and wide, with great shipping value. The annual cargo flow is large, and the transportation is very busyAmerican economyA relatively developed plain area.There are many importanteconomic centerAnd transportation hubs, such as St. Louis andIndianapolisIt is located at the middle reaches of the Mississippi River.
The most distinctive feature isSt. Louis The huge steel arch built on the bank of the Mississippi River towering into the clouds, the beautiful Mississippi River flows like a jade belt from the foot of this magnificent Suriname arch, adding a variety of scenery to the city.The 192m high Suriname Arch was started in 1964 and completed in two years.Take the elevator to the top floor, and overlook the beautiful scenery on both sides of the Mississippi River.
downstream
Mississippi River
staygeographerIt seems that the lower Mississippi River has long been a typical river with twists and turns and siltation;The river formed countless bends on the flood plain, leaving manyMeanderRelics, bow shaped lakeOxbow lakeAnd swamp backwater.The lower reaches of the Mississippi River extend from the mouth of the Ohio River toMississippi DeltaThe total length of the estuary is 1570 kilometers.The main tributaries areWhite River、Arkansas River、Red RiverEtc.The lower reaches of the river are relatively flat, and the curvature of the river is not large. The climate here is mild, and the rainfall is abundantSubtropicalWet areas.Most of the Mississippi River is a plain. The Ohio River mouth is 25 kilometers wide. There are six branches at the mouth, about 30 kilometers long, like bird feet.80% of the river's water flow into the sea passes through three main branches, namely, the Southwest Waterway, the South Waterway and the Alot Waterway.The average annual sediment discharge of the river is 495 million tons, which accumulates at the estuary into a huge area of 26000 km2Bird foot deltaAnd continues to extend to the Gulf of Mexico at an average annual rate of 96 meters.
The valley is gradually widened along the river mouth, which can be more than 100 kilometers wide.Most of the valley bottom has been swamped, and the river body is extremely curved, with many old river beds andMeander。The soil here is fertile and has been highly utilizedCornLargest place of origin.
In the lower reaches of the Mississippi Riverport cityMemphis.A large distribution center for agricultural and livestock products in the United States, especially famous for producing cotton, cottonseed oil, hardwood, etc.Now it has formed agricultural machinery manufacturing, automobile assembly, pharmaceutical, wood and agricultural product processing bases.
Delta
Mississippi Delta
The Mississippi River starts to enter under Baton RougeDeltaRegion.The delta area is low and flat, with marshes on both banks of the river embankment,depressionDistribution, the estuary is divided into three branches and stretches overseas in the shape of bird's claw.variousTributaryA large amount of alluvium is deposited nearby every year, which has increased the area of the delta by 129 square kilometers in the past 150 years.The delta still extends to the Gulf of Mexico at an average rate of 75 meters per year.
New Orleans, the largest seaport in the United States, is located in the Mississippi River Delta.It mainly undertakes bulk goods and materials transferred to all parts of the world.There are 380 kilometers of deep water coastline, and nearly 100 ships from all over the world come in and out every day.Become second only toNetherlandsRotterdam Port is the second largest seaport in the world.
In Baton Rouge, 120 kilometers northwest of New Orleans, the river is wide and deep, which is very convenient for shipping. At the same time, it is also an important part of the southern United StatesIndustrial city。The petrochemical products produced in this city are second only toHouston, ranking second in the United States.Natural Science Museum andAnglo - The American Museum of Art is the most fascinating place, with more than 4 million domestic and foreign tourists coming here every year.[2]
Main tributaries
The tributaries of the Mississippi River system mainly include the upper Mississippi River, the eastern tributary Ohio River, the western tributary Missouri River, Arkansas River, White River and Red River.
The Mississippi River above Niapolis is called the Upper Mississippi River, with a total length of 827km.The tributary of the upper Mississippi River is adjacent to Lake Michigan and Lake Superior of the Five Great Lakes System, and there are many small lakes in the region, which play a great role in the supply and regulation of water sources.
Ohio RiverThe total length is 1578km, the drainage area is 528000 km, and the annual average runoff of the estuary is 230.2 billion m.The total fall from Pittsburgh to the estuary is 127m.The Tennessee River is the main tributary of the Ohio River, with a total length of 1050km, flowing through seven states in the southeast of the United States, with a drainage area of 105900 km2 and an annual runoff of 25.4 billion m.The total head is 157m.
Another tributary isCumberlandRiver, drainage area 47000 km, river length 1158 km, estuaryAverage annual runoff24 billion m.The Missouri River is the largest tributary of the Mississippi River.The total length is 4126km, and the drainage area is 1.372 million km. The main source streams are the Jefferson River, Madison River and Caladin River in the southwest of Montana. The three rivers converge to form the Missouri River. The elevation of the junction is about 1220m, and it flows northward through a steep and narrow valley to the Great Falls City. Above is the upper reaches of the Missouri River.This section of river is a typical deep mountain and canyon section, with rapid water flow. The average gradient of the river channel reaches 11.36 ‰. For example, the water surface of some river sections, such as the 16km section near the Great Falls City, drops 122m, forming a series of waterfalls.The river below turns eastward, enters the mountains and highland plains, and reaches the middle reaches of Suzhou City.The lower reaches of Suzhou City are the lower reaches of the river. The river swings frequently in the alluvial riverbed. The river course is winding and braided, and flows into the Mississippi River at 16km north of St. Louis, Missouri.The flat slope of the middle and lower reaches is generally 1.9 ‰.The average annual runoff of Missouri River is 70.3 billion m, and the maximum flow at the estuary is 25500m/s.In the tributaries of high plain areas, soil erosion is serious.For example, the sediment content of Huangshi River, Porter River and Baihe River can reach 30 by weight.The Missouri River has a total annual average sediment discharge of 218 million tons and an annual average sediment concentration of 3.1 kg/m, which is the most sandy river in the United States, so it is also called the Dani River.
the missouriThe main tributaries are Milk River, Huangshi River, James River, Tirat River and Kansas River.
Milke RiverWith a length of 1170km, a drainage area of 58000 km, an average annual flow of 20m/s and a runoff of 630 million m.Huangshi River is 1080km long, with a drainage area of 178000km and an average annual flow of 370m/s.James River is 1142km long, with a drainage area of 57000km.
Xilat River is 1593km long, with a drainage area of 219900km and an average annual flow of 169m/s.The Kansas River has a total length of 1140km, drainage area of 159000km, average annual flow of 186m/s, and runoff of 5.87 billion m.
ArkansasThe Arkansas River also originates from the Rocky Mountains, flows from west to east, and flows into the Mississippi River in Desha County, Arkansas.The total length is 2333km, and the drainage area is 416000km.In natural conditions, the annual average flow of Changshan Station is 1700m/s, the annual sediment discharge is 95 million t, and the maximum peak flow is 19800m/s.The main tributary of the Arkansas River, the Canadian River, is 1458km long with a drainage area of 121500km, and its tributary, the North Canadian River, is 1223km long with a drainage area of 36000km.
White RiverIt originates from Madison County, Arkansas, with a total length of 1102km, a drainage area of 72500km, and an average flow of 909m/s.
Red RiverThe Red River is a right bank tributary near the mouth of the Mississippi River. It originates from Tirabransa Creek, New Mexico, with a total length of 2075km, a drainage area of 241000km, and an average flow of 1585m/s.The Woxito River is its largest tributary, with a total length of 1010km, a drainage area of 21000km, and an average annual flow of 44m/s.[1]
Natural characteristics of the basin
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landforms
Far View of Mississippi River
The terrain of the United States is composed of three vertical zones.The first longitudinal belt is the western mountains and plateaus. The Rocky Mountains have more than 40 peaks with an altitude of more than 4200m;The second tandem is the Appalachian Mountains in the east, with the main peak at 2038m above sea level;The third vertical belt is the central plain, including the Great Plain and the central lowland. The Great Plain is generally 600-1500m above sea level.The Mississippi River system is located between 80~118 west longitude and 29~49 north latitude, which is the central plain.
The two sides of the Upper Mississippi River are low in terrain and densely covered with lakes, which is the channel connecting the mainland of the United States and the northeast.Although the Missouri River originates in the highlands of the Rocky Mountains, most of the terrain in the basin is flat or slightly undulating.Most of the Ohio River is located in the central lowland, with an elevation below 150m, and connects with the Appalachian Mountains in the east.The main stream of the Mississippi River flows through the central lowland. The middle reaches of the river are wide and the lower reaches of the river are tortuous. The river is 2500~3000 m wide and the water regime is stable.Since 1898, due to the continuous accumulation of sediment at the estuary, the river delta has extended to the sea for an average of 30m every year, forming a delta with a width of about 300km and an area of 37000km.The delta area is low and flat. There are marshes and depressions on both sides of the river bank. The estuary is divided into six Han rivers stretching outward like bird feet, which is called "bird foot delta".[1]
Climatic precipitation
The monthly average temperature in the Mississippi River basin in winter isLouisiana13 ℃ (55 ℉) in the southern subtropical region and - 12 ℃ (10 ℉) in the northern sub polar region of Minnesota.The average monthly temperature in summer is 28 ℃ (82 ℉) in Louisiana and 21 ℃ (70 ℉) in Minnesota.
Precipitation comes from low altitude moisture from the Gulf of Mexico and fromthe pacific oceanSome low and high altitude moisture.The precipitation in winter and spring occurs near the front when a cyclone storm usually moves from west to east passes through.The average monthly precipitation in winter is 127 mm or more in the south, 76 mm or more in most parts of the Ohio Basin, and less than 25 mm in the west and north of the Great Plains.The rainfall in summer and early autumn is mostly showers and thunderstorms, as well as weak frontal storms.monthly averagerainfallIn southern Louisiana and TennesseeNorth CarolinaThe mountain area is 152 mm, and the great plain is only 51~76 mm.
Eastern half of the basinclimateIt is humid, with large flow in the Tennessee River Basin, Ohio River Basin and the southern Mississippi River Basin in winter and spring.From Central Texas toNorth DakotaThere is a subtropical humid climate zone extending from north to south in the east, which is neither completely humid nor semi-arid.In the west, there is a semi-arid climate of the Great Plains, along the ridge of the Rocky MountainsAlpine climateMainly, snow in winter melts downstream in spring and early summer.[1]
River nickname
Mississippi River
Due to its vastness and historical significance, the Mississippi River has many nicknames:
*The Father of Waters
*The Gathering of Waters
*The Big Muddy (more commonly associated with the Missouri River)
*Big River
*Old Man River
*The Great River
*Body of a Nation
*The Mighty Mississippi
*Great Chain El Grande (de Soto)
*The Muddy Mississippi
*Old Blue
*Moon River
hydrographic features
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The river basin is vast and the climate conditions are different in different regions, sohydrographic featuresThere are some differences.
Runoff
The latitude of the upper reaches is slightly higher, mainly supplied by snow melting and rainwater in spring, and the highest in Aprilwater level, June due toprecipitationIncrease, secondary high water level occurs,Flood periodMarch to July, DecemberDry season。The annual average flow is 2900 m3/s.It is frozen in winter,Sediment concentrationLess.
The average annual flow in the middle reaches is 5800 m3/s. The flood period is from March to August, the highest water level occurs in June, and the dry season is in December.As the west bank flows through the inflow of tributaries in semi-arid areas,river sediment concentration enlarge.
After the downstream flows in from the Ohio River, the water volume increases greatly, and the annual average runoff reaches 13400 m3/s. The flood period is from January to June, the highest water level appears in April, and the dry season is October, with large sediment concentration.The right bank of the main stream is headed by the Missouri River, which has large length, small water volume and obvious seasonal changes;The left bank is led by the Ohio River, which has small length, large water volume and moderate seasonal variation.Most of the river basins areplain, providing richIrrigation water sourceAnd industrial and domestic water.However, due to small gradientriver flatBroad. In the past, when the river rose sharply in spring and summer, the low-lying areas along the river at the middle and lower reaches were prone to floodingAmericaIt is called the Nile.
Flood characteristics
Mississippi River Scenery
It's a big river like MississippihydrologyIt has always been the object of great research. In fact, by the 1920s, it was generally believed that the hydrological conditions of the river had been well understood, and the control facilities that had been built were enough to subdue the river.However, in 1927, the largest flood ever occurred in the lower reaches of the Mississippi River. More than 59570 square kilometers of land were floodedRailwayTraffic and transportation, such as telephone lines, were interrupted in many places, and farmland, factories and even the whole town once soaked into the water.A large number of properties were destroyed and at least 250 people were killed.River engineers began to reexamine the hydrological problems of the Mississippi River.
Since the abnormal situation occurred in 1927, the average flow of main tributaries into the lower Mississippi River has been carefully monitored.The main river flows through MississippiVicksburgAverage of (Vicksburg)flowThe measured value is 16131 m3/s.Generally speaking, the west tributary is the most unstable.When it reaches the peak in spring and early summer, it is equivalent to 3-4 times of the water input into the main river channel in winter.The upper reaches of the Mississippi River and its tributaries reach the highest water level at about the same time (March to June), during which the early summer rainfall occurs after snow melting.However, the winter flow in this area is also very considerable.The peak flow of the Ohio River appeared earlier, not far before it joined the Mississippi RiverIllinoisMetropolis Largestmonthly averageThe flow usually occurs in March, when the flow provided by the Ohio River can account for more than 3/5 of the flow measured at Vicksburg in the lower reaches of the Mississippi River.Therefore, the Ohio River is the main cause of flooding in the lower Mississippi River.The flood may be aggravated by the following circumstances: early rainfall on the Great Plains, sudden hot weather in early spring, melting of snow in the north, torrential rain in the downstream, etc.When the above situation occurs, the downstream river overflows the river bank, threatening the embankment.The tributary is blocked back, forming a lake on the far side of the embankment.The flow not exceeding 2~3.5 knots (2.5~4 miles/hour) at ordinary times can be doubled at the narrow part of the main river channel.For example, the low flow in winter recorded by Vicksburg Monitoring Station in 1936 was only 2655 m3/s, and the flow measured during the high water level period of the next year was 58298 m3/s.
River ecology
The Mississippi River and its flood plains feed more than 400 different wildlife resources, and 40% of waterfowl in North America migrate along the Mississippi River.Although the natural vegetation of the Mississippi River Valley itself is the product of climate and soil rather than the river, the marsh and backwater area of MississippiecologyBut it is worth noticing.From the wild rice swamp in Minnesota to the deltacoastMarshland, a small area with flourishing animals and plants, is common along rivers.In these areas, lush natural vegetation, relatively independent natural environment and plants provided by sedge, pool grass and millet provide good habitat for waterfowl.These birds migrate up and down the river with the seasons, which is called the Mississippi Flying Road.Use this noun to call this vast slaveEstuarine deltaUntil the air highway in the summer camp in northern Canada, it can be said that it is the most accurate.It is estimated that a total of 8 million ducks, geese and swans gather in the downstream of the flight road in winter, and more other birds fly toLatin America。The most typical migratory birds on the flight route arecanada goose And smallSnow goose, a large number ofmallardAnd ducks, andBlack duck、Red necked duck、Needle tailed duck、Ring necked duckas well ascoot 。
The most important fish in the river are several catfish (several in the middle and lower reachesCatfishIt can grow to a considerable size, and local commercial fishing is conducted for it);There are drum eye fish andAsian mouth fish(The upstream is rich in these fish, which areMinnesotaandWisconsinFishing provides the foundation);alsocarpandEuropean croaker。CrocodileVery few, only in the most remote backwatersI will see it.Shrimp and crab fishing in salt water areas is also declining.
Threats and disasters
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The Mississippi River, which ranks the 10th among the top ten endangered rivers in the United States, is facing threats: navigation infrastructure, levees and pollution
Management failure
Mississippi River
Because of theUS Army Corps of EngineersThe failure of flood control strategy focused on how to manage the Mississippi River to provide services for the shipping industry and flood control, so the depth, flow, flood plain area andWildlife resourcesAnd so on.Many losses include: more than half of the flood plain in the basin was cut off by the flood embankment;Millions of acresWetland resourcesCountless marginal channels and sandbars have been damaged and damaged;The most basicWetland plantThe number is decreasing significantly;Sand setting and erosion are increasing,fishAnd the living habits of mussels have been destroyed.[3]
"Sea of Dead Fish"
In September 2010, thousands of dead fish, including a whale, were found in the Mississippi River in western Louisiana.There are also crabs, stingrays, sea eels, spotted trout and red trout.
Mississippi River
A piece of water near the Gulf of Mexico in Louisiana, USA, has become an astonishing "sea of dead fish": countless dead fish, crabs and eels cover the water surface tightly.Local TV reporters even found the body of a whale in the waters at the mouth of the Mississippi River.All parties therefore called on the local government to investigate.[4]
Local residents said that although a large number of aquatic animals would die in the above waters every summer due to the "sudden hypoxia" caused by climate change, this would often only cause the death of one kind of fish, rather than the "collective death of multiple species" on such a large scale.Some people suspect that,BPThe leakage accident of oil production platform may be the real cause of the above sea of dead fish.
natural disaster
(Picture) Mississippi River
The recorded historical flood years on the main stream of the Mississippi River are 1543, 1785, 1844, 1850, 1882 and 1897;In the 20th century, 1903, 19121913, 1927, 1945, 1950, 1973, 1974, 1975, 1979, 1983 and 1993.Over the past hundred years, the Mississippi River has experienced 37 major floods, with an average of one flood in three years.
In the flood of 1927, more than 200 levees of the Lower Mississippi River burst, covering an area of about 67000 square kilometers, and towns and villages on both sides were severely damaged.Memphis was besieged by floods for 107 days, more than 100 people died, 800000 people were homeless, and the loss was 2.55 billion US dollars in 1973.
In the 1973 flood, many levees burst, inundating an area of more than 68000 square kilometers, killing 11 people and leaving 69000 homeless.
In 1993, the worst events in the 20th century occurred in the Mississippi River and Missouri River basins in the upper and middle west of the United Statesflood。The peak flow of St. Louis Station reached 30560 m3/s, the maximum flow measured for more than 130 years, 27% higher than the previously recorded flood, the water level nearly 2 meters higher than the previously recorded water level, and the flood duration in the flood season reached 104 days.
The flood at St. Louis Station is equivalent to the flood with a return period of 150 to 200 years, and some tributary stations are the flood with a return period of 500 years. The loss caused by this flood is estimated to be 15 billion dollars, with at least four years of deaths and 54000 homeless people.In addition, local floods have also occurred in various tributaries.For example, in July 1996, a sudden rainstorm flood occurred in northern Illinois, with a 24-hour rainfall of 425 mm. In 1997, the largest spring news since 1936 occurred in the Ohio River basin.These two floods also caused heavy losses, and the flood losses of the Mississippi River caused by hurricanes were also quite serious.
From the first recorded tropical storm in the Gulf of Mexico on September 19, 1559, more than 166 hurricanes hit or threatened the coastal area of Louisiana, including the estuary delta of the Mississippi River.
In 1909, the hurricane hit the area from Mexico to New Orleans, and the storm surge flood killed 700 people.
Similar disasters occurred in 1915, 1919 and 1965.
Economic culture
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The Mississippi River is a treasure house of national culture and entertainment.Every year, the output value of tourism, fishing, leisure and entertainment industries alone can reach 21.4 billion US dollars, providing 351000 jobs for all parts of the basin.The Mississippi River also supports the $12.6 billion shipping industry, providing 35300 related jobs.Half of the country's grain andsoybeanAre transported by the upper Mississippi River.
entertainment
Water skiing was invented in the Piping Lake area between Wisconsin and Minnesota.Along the Mississippi River, there are 7National Park ServiceArea managed.The purpose of the Mississippi National River and Recreation Area is to protect and show the Mississippi River itself.The other 6 areas are (arranged from north to south):
Effigy Mounds National Monument
Jefferson National Expansion Memorial (hereinafter referred to as the Great Arch)
Vicksburg National Military Park
Natchez National Historical Park
New Orleans Jazz National Historical Park
Jean Lafite National Historical Park and Preserve
literature
William Faulkner Most of his works are set in his hometown, the Mississippi River basin and the delta region, and he has created a county in the Mississippi River basinYoknapatafa。
South AmericanAmazon, Africanthe NileAnd ChineseYangtze RiverIt is also called the four longest rivers in the world.The beautiful and rich Mississippi River originates from theRocky MountainsIn the northern section, among the mountains and mountains, it is winding for thousands of miles, running through the Great Plains of the United States from north to south, and flowing into the Gulf of Mexico, with a total length of 3950 kilometers.However, it is 418 kilometers shorter than the Missouri River, the largest tributary.according toHeadwater of riverIn the principle of remoteness, add the length of the Missouri River to the length below the mouth of the Mississippi River from the Missouri River, and the Mississippi River is 6262 kilometers long, which is the longest water system with the longest flow, the largest drainage area and the largest water volume on the North American continent.
The flowing water of this great river has nurtured people in the whole Mississippi River basin like milk.The American people have long known the Mississippi River as the "Old Man River".Its name originates from the Algonquian people living in Wisconsin in the northern United States（IndianThey called the upper part of the river "Mississippi"."Mississippi" means "big", "Sibi" means river, and "Mississippi" means "big river" or "father of river".
Value traceability
In its long flow, the Mississippi River moistens 41% of the land in the mainland of the United States and has more water than any other American river.The Mississippi River is also home to millions of Americansdrinking waterSource of.Watersheds include all or part of the 31 states of the United States and two provinces of Canada.The Mississippi River is also used as the state boundary of many states.The Mississippi River has been the main north-south shipping artery since the beginning of reclamation.However, the Mississippi River disasters were frequent in history.In the early 20th century, the middle and lower reaches of the river continued to flood, most of the buildings in towns and villages were destroyed, farmland and orchards were damaged, and industry and transportation were almost completely paralyzed.Many people have been displaced from their homes and suffered serious economic losses.
In 1928, the US government formulated the flood control act for comprehensive regulation of the Mississippi River and the plan for trunk and tributary projects. The middle and lower reaches of the main stream were all flood controlled by dikes.After more than 60 years of efforts, the basin has receivedcontrol flood、shipping, water and electricityirrigation, fish farming and other comprehensive economic benefits.Today, after the development and construction of the American people, the Mississippi River Basin has undergone profound changes over the past half century. Floods have been controlled and water sources have been fully utilized.Today, there are green riverbanks everywhere, and vibrant industrial towns are scattered everywhere. Busy fleets and light yachts have revived the long established river of the United States. The beautiful and rich Mississippi River has made the land of the United States more beautiful and charming.
Shipping value
The Mississippi River isU.S.AThe main artery of north-south shipping.The main stream can sail from the estuary to Minneapolis, and the channel is 3400 kilometers long.In addition to the main stream, about 50 tributaries are navigable.The channel with a water depth of more than 2.7 meters is 9700 kilometers long.The total navigable mileage of trunk and tributaries is 25900 kilometers, and there are severalcanalIt is connected with the Great Lakes and other water systems, forming a huge water transport network.Except upstream and tributaries of main streamIllinoisThe Missouri River can be navigable all year round, except for the ice from January to February. Seagoing ships can directly reach Baton Rouge, 395 kilometers away from the estuary, with high shipping value.freight transportThe turnover volume accounts for about 60% of the domestic inland waterway freight transport, mainly transporting oil, flour, cotton, coal, metal and mechanical products.The main ports along the coast areSt. Louis 、Memphis、Baton RougeandNew OrleansEtc., whereLouisvilleIt's on the Ohio River.The hydraulic reserve in the basin is 26.3 million kilowatts, mainly distributed in the Ohio River and its tributaries, with a high degree of development.Because one branch of the Mississippi River is directly connected toThe Great LakesIn addition, people have repaired it a lotdamTherefore, in an experiment, the boat passed through the river and reached the Great Lakes.
Mississippi River Lock
the First World WarThe river trade has been greatly revived.Other transport routes are very crowded, so river transport has become a channel of increasing value.stayfederal governmentUnder the initiative, new barge routes were opened up. By 1931, the annual freight volume along the Mississippi River was twice that of any year in the last century.
The commercial use of Mississippi Waterway has steadily increased.The main goods are petroleum and petroleum products, coal and coke, steel, chemical products, sand and sulfur in terms of volume.The increase of bulk loading and unloading inevitably means that a few key port cities have achieved rapid development by defeating their rivals.
In 1879, the Mississippi River Commission, established by act of Congress, supervised the implementation of a large-scale river engineering project, which brought profound changes to the face of the Mississippi River.The main steps of the shipping improvement plan included approval in 1896 from Cairo, Illinois to LouisianaBarton RougeExcavate a water channel 3 meters (9 feet) deep and 76 meters (250 feet) wide in the shallow section of Baton Rouge;In 1928, it was approved to widen the waterway to 91 meters (300 feet);The project of deepening to 3.7 meters (12 feet) was started in 1944 and is still in progress.In addition, from Barton Rouge toGulf of MexicoThe 14 meter (45 foot) deep waterway is still under construction since the approval of Congress in 1945.The outstanding achievement of the regulation of the upper reaches of the river is the construction of 29 sluices and dams so that the 3-meter deep river can be traced back to Minneapolis - Sao Paulo.There are extensive and complex related waterways connected with the Mississippi River, including those in the southFloridaCoast between the border with MexicolandlockedWaterway, the waterway that leads the Ohio River to its tributaries and the waterway that leads to the Great Lakes and St. Lawrence Waterway through the Illinois Waterway.
Governance development
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Uniform standard of waterway
Shipping on the Mississippi River began in the early 18th century.In the 19th century, the waterway in the lower reaches of the main stream, the upper Mississippi River and the lower reaches of the Ohio River began to be regulated.In addition to the general channel dredging, the measures also include the side canal with a ship lock to bypass the rapids.At the beginning of the 20th century, navigation gates and dams were built on the river to channel the channel.From 1911 to 1940, 46 class movable locks were built on the main stream of the Ohio River, taking the lead in channelization.Later, the upper Mississippi River, Tennessee River and Arkansas River were also channelized.More than 100 ship locks have been built.So far, the whole river system has formed a unified channel.
The main tributaries of the Mississippi River are connected with rivers and seas in the rivers and lakes, forming a channel network extending in all directions, which is an important reason for the sustainable development of the shipping industry of the river system.The channels, locks and ships in the water system all adopt unified standards, so that each channel can communicate with each other.The unrestricted shipping is another reason for the sustainable development of the shipping industry.The minimum water depth of the Mississippi River system channel is 2.74m, only the downstream of the main stream (Kailuo Baton Rouge) is 3.65m, and the estuary channel is 9-12m.The minimum channel width is 91.4m.There are two standards for the dimensions of main ship locks, namely 33.5m × 183m and 33.5m × 366m. The water depth above the sill is 3.96~4.66m.Ships have also been standardized.For example, the length of open barge is 53.34m, 59.44m and 88.39m;The width is 7.92 m, 10.67 m and 15.24 m respectively;The capacity is 1000 t, 1500 t and 3000 t respectively;The draft is 2.74m.The main fleet sailing on the mainstream and tributaries of the Mississippi River is composed of 8 barges with a width of 10.6m and a length of 59.4m, with a width of 32m, a total length of 178m, a draft of 2.59m, and a carrying capacity of 11152t. The fleet is composed of 15 similar barges with a size of 32m × 343m and a carrying capacity of 20910t.The above two fleets can pass through the locks with the effective length of 183m and 366m, but the long fleets will break up when passing through the 183m locks, and pass through the locks in two times.[1]
Flood control measures
With the economic development of downstream areas and the emergence of large industrial and commercial cities, flood control plays an increasingly important role.
Since the 1930s, large-scale flood control engineering construction has been carried out in the lower reaches of the Mississippi River, and the embankment top elevation has been generally raised.There are 3540km embankments in total, of which the total length of the main embankment is 2590km, the average height is 7.5m, and the height of individual embankment sections reaches 12m.Four flood diversion channels have been built, with a total flood diversion capacity of 56600m/s.There are 16 bend cutting and straightening works, which shortens the 740km reach by 274km, lowers the water level of Arkansas by about 3.6m, and lowers the water level of Vicksburg by about 1.8m.In addition, a large number of spur dikes and bank revetments have been built in combination with shipping.
With the development of regional economy, the comprehensive development of tributaries has been put on the agenda.In 1936, the Congress passed the General Act on Flood Control, which stipulated that the flood control should focus on tributary reservoir flood regulation, supplemented by embankment construction, flood diversion and river regulation.However, it was soon discovered that building reservoirs on the Missouri River and the Arkansas River could not completely solve the flood control problem in the lower reaches of the main stream of the Mississippi River.Therefore, the comprehensive flood control measures were emphasized later, such as changing the land use of the flooded area and implementing non engineering measures such as flood control insurance.
The flood control of the Mississippi River has not been completely controlled, although many flood control works have been built after long-term efforts.With the development of the economy in the flooded area, the flood losses are more and more serious. The 1973 flood, the 1993 summer flood, and the 1996 and 1997 local floods all suffered heavy losses.After the 1993 flood, a comprehensive summary of the flood was made and various flood control measures were reassessed.It is considered that the Mississippi River is likely to have a larger flood than that in 1993. The industry and agriculture account for 50% of the flood losses, and 80% of the agricultural losses are caused by excessive rainfall and soil moisture;The reservoir flood regulation reduced the loss by 11 billion dollars, and the dike reduced the loss days.However, only 10% of the residents in the flooded areas have purchased flood control insurance, and 68% of the embankments (mainly non federal ones) have been damaged.Under the authorization of the Congress, the Army Corps of Engineers specially put forward the Floodplain Management Assessment FPMA Report on the flood control strategy of the Missouri Mississippi River system in the 21st century in 1995, which clearly defined that comprehensive (including many non engineering) measures must be taken to achieve flood control and disaster reduction,Such as scientifically planning land use according to flood risk, strengthening flood forecasting and early warning, establishing emergency response and rescue mechanism, and promoting flood insurance.Flood control of rivers should be considered from the overall perspective of natural environment protection.[1]
Governance measures
According to the introduction of American experts, the experience of comprehensive management of the Mississippi River can be summarized as follows:
1、 The government attaches importance to, issues laws and develops in an orderly manner.It is a country that attaches great importance to legislation. Through legislation, it plans the future project construction plan in advance.So that the construction of water conservancy, hydropower and water transport projects has laws to follow.
2、 Entrust the Engineer Corps to carry out scientific planning and construction from three aspects of water conservancy, hydropower and water transportation.
3、 The channel, ship lock and fleet have unified standards and excellent performance, achieving serialization, standardization and standardization, which not only improves the shipping efficiency, but also facilitates maintenance.
4、 Attach importance to the role of scientific research in river regulation and engineering construction.Every year, the government has a large amount of funds invested in the Vicksburg Waterway Experiment Station to carry out relevant research, achievement transformation, mathematical model, physical model, mathematical ecological model experiments, optimize the comparison and selection of schemes, and provide guarantee for engineering design, construction and maintenance.
5、 Advocate public participation and enhance river awareness.The Mississippi River Museum has been established in Tunica County in the lower reaches of the Mississippi River to publicize the knowledge of river changes, river contributions, people and rivers getting along, ecological environment, and treating rivers with pictures and texts, or with physical models to the public.
