 Morgan City, Louisiana inundated during May 1973 | |
| Date | December 1972-June 1973 |
|---|---|
| Location | Mississippi Valley, Mississippi River Delta |
| Deaths | 33 |
| Property damage | $252.7 million USD |
The Mississippi flood of 1973 occurred between March and May 1973 on the lower Mississippi River. [1] The flooding was the third most severe along the U.S.'s Mississippi River during the 20th century.
A series of unusually cold winters in the river basin concluded in the winter of 1972-1973, when high precipitation saturated much of the watershed, especially in the Ohio Valley and lower Mississippi Valley. This was followed by more rain in early 1973, with river flow cresting on March 31 at Red River Landing, Louisiana, and a heavy snowmelt in the Rocky Mountains which caused western tributaries such as the Missouri and Arkansas to form a final catastrophic high in June. [2] The flood resulted in the largest volume of water to flow down the Mississippi since the Great Mississippi Flood of 1927. Both the Bonnet Carre Spillway and the Morganza Spillway were employed. The Bonnet Carre was fully opened between April 7 and June 14 for a record 75 days. The 1973 flood was the first time the Morganza Spillway was opened: from April 19 through June 13.
At Memphis, Tennessee, the Mississippi was over flood stage for 63 days, more than that of the historic 1927 flood, and the river was above flood stage for an even longer 107 days at upstream Cairo, Illinois. [3] Out of the seven largest floods on the Mississippi between 1927 and 1997, the 1973 event ranked third in both volume discharged and duration but only sixth in flood height. [2] Over $250 million of damages were incurred mainly in the Mississippi Valley states of Missouri, Arkansas, Tennessee, Mississippi and Louisiana.
The largest single inundation, south of St. Louis, Missouri, was caused by a series of catastrophic levee failures on the west bank of the river and ultimately covered almost 9,400 square miles (24,000 km2). [4] The Morganza Spillway was opened, flooding portions of the Atchafalaya River basin in Louisiana and causing the deaths of thousands of head of livestock and white-tailed deer. [5] The 1973 flood was notable for nearly causing the failure of the Old River Control Structure above the Mississippi River Delta, which would have sent the Mississippi's main channel flowing into the Atchafalaya River and bypassing most of the delta region including the major port of New Orleans, Louisiana. [6]
In spite of record high flows, flood stages were not as high as past events. [1] Red River Landing, Louisiana reached 58.22 feet on May 13 and was 9th highest crest of record. The flood stage at Baton Rouge was 42.10 feet on May 10. Farther down the River at Donaldsonville the flood stage reached 32.30 feet on April 9, which was the 10th highest crest of record. At Reserve, the crest was 24.50 ft on April 8, 7 highest on record. On April 7, New Orleans crested at 18.47 ft.
The flow past Baton Rouge peaked at 1.38 million cubic feet per second (ft3/s) on May 13. The project design flood capacity at Baton Rouge is 1.38 million ft3/s (39,077.25 m3/s). The flow past New Orleans peaked at 1.257 million ft3/s (35,594.28 m3/s) on April 15; the project design flood flow is 1.25 million ft3/s with the balance flowing through the Bonnet Carre Spillway. Discharge through the Bonnet Carre Spillway increased the level of Lake Pontchartrain to 3 feet above normal, peaking at 14.7 feet at mid-lake.
The Mississippi River is the second-longest river and chief river of the second-largest drainage system in North America, second only to the Hudson Bay drainage system. From its traditional source of Lake Itasca in northern Minnesota, it flows generally south for 2,340 miles (3,766 km) to the Mississippi River Delta in the Gulf of Mexico. With its many tributaries, the Mississippi's watershed drains all or parts of 32 U.S. states and two Canadian provinces between the Rocky and Appalachian mountains. The main stem is entirely within the United States; the total drainage basin is 1,151,000 sq mi (2,980,000 km2), of which only about one percent is in Canada. The Mississippi ranks as the thirteenth-largest river by discharge in the world. The river either borders or passes through the states of Minnesota, Wisconsin, Iowa, Illinois, Missouri, Kentucky, Tennessee, Arkansas, Mississippi, and Louisiana.
Morganza is an incorporated village near the Mississippi River in Pointe Coupee Parish, Louisiana, United States. The population was 610 at the 2010 census, down from 659 in 2000. As of 2020 the population was 525. It is part of the Baton Rouge Metropolitan Statistical Area. The village's zip code is 70759. The Morganza Spillway, a flood control structure between the Mississippi River and the Atchafalaya Basin, is located nearby.
The Atchafalaya River is a 137-mile-long (220 km) distributary of the Mississippi River and Red River in south central Louisiana in the United States. It flows south, just west of the Mississippi River, and is the fifth largest river in North America, by discharge. The name Atchafalaya comes from Choctaw for 'long river', from hachcha, 'river', and falaya, 'long'.
The Old River Control Structure is a floodgate system in a branch of the Mississippi River in central Louisiana. It regulates the flow of water from the Mississippi into the Atchafalaya River, thereby preventing the Mississippi River from changing course. Completed in 1963, the complex was built by the U.S. Army Corps of Engineers in a side channel of the Mississippi known as "Old River", between the Mississippi's current channel and the Atchafalaya Basin, a former channel of the Mississippi.
The Mississippi Sound is a sound along the Gulf Coast of the United States. It runs east-west along the southern coasts of Mississippi and Alabama, from Waveland, Mississippi, to the Dauphin Island Bridge, a distance of about 90 miles (145 km). The sound is separated from the Gulf on its southern side by the Mississippi–Alabama barrier islands: Cat, Ship, Horn, West Petit Bois, Petit Bois, and Dauphin. Ship, Horn, West Petit Bois and Petit Bois Islands are part of the National Park Service's Gulf Islands National Seashore. Those islands separate the sound from the Gulf of Mexico. The sediment of the islands was created partly by the ancient Mississippi River when the St. Bernard Lobe of the Mississippi Delta was active over two thousand years ago. The expansion of the St. Bernard subdelta slowly isolated the Mississippi Sound from ocean dynamics of the open Gulf of Mexico.
The Bonnet Carré Spillway is a flood control operation in the Lower Mississippi Valley. Located in St. Charles Parish, Louisiana, about 12 miles (19 km) west of New Orleans, it allows floodwaters from the Mississippi River to flow into Lake Pontchartrain and thence into the Gulf of Mexico. The spillway was constructed between 1929 and 1931, following the Great Mississippi Flood of 1927, and has been designated as a National Historic Civil Engineering Landmark by the American Society of Civil Engineers.
The Atchafalaya Basin, or Atchafalaya Swamp, is the largest wetland and swamp in the United States. Located in south central Louisiana, it is a combination of wetlands and river delta area where the Atchafalaya River and the Gulf of Mexico converge. The river stretches from near Simmesport in the north through parts of eight parishes to the Morgan City southern area.
The Lower Mississippi River is the portion of the Mississippi River downstream of Cairo, Illinois. From the confluence of the Ohio River and Upper Mississippi River at Cairo, the Lower flows just under 1000 miles (1600 km) to the Gulf of Mexico. It is the most heavily travelled component of the Mississippi River System.
Airline Highway is a divided highway in the U.S. state of Louisiana, built in stages between 1925 and 1953 to bypass the older Jefferson Highway. It runs 115.6 miles (186.0 km), carrying U.S. Highway 61 from New Orleans northwest to Baton Rouge and U.S. Highway 190 from Baton Rouge west over the Mississippi River on the Huey P. Long Bridge. US 190 continues west towards Opelousas on an extension built at roughly the same time.
The Morganza Spillway or Morganza Control Structure is a flood-control structure in the U.S. state of Louisiana. It is located along the western bank of the Lower Mississippi River at river mile 280, near Morganza in Pointe Coupee Parish. The spillway stands between the Mississippi and the Morganza Floodway, which leads to the Atchafalaya Basin and the Atchafalaya River in south-central Louisiana. Its purpose is to divert water from the Mississippi River during major flood events by flooding the Atchafalaya Basin, including the Atchafalaya River and the Atchafalaya Swamp. The spillway and adjacent levees also help prevent the Mississippi from changing its present course through the major port cities of Baton Rouge and New Orleans to a new course down the Atchafalaya River to the Gulf of Mexico. The Morganza Spillway, operated by the U.S. Army Corps of Engineers, was opened during the 1973 and 2011 Mississippi River floods.
Elliot City is a ghost town that was located in Pointe Coupee Parish's 10th Ward, approximately 6 miles west of Livonia, Louisiana United States. The site of the town itself is located at coordinates 30.555942, -91.662475, and is covered or partially covered by the current U.S. Route 190 roadway.
Butte La Rose is an unincorporated community in St. Martin Parish, Louisiana, United States. In the 21st century, the area is known for its wilderness campgrounds, and the Atchafalaya Welcome Center.
Major floods along the Mississippi River in April and May 2011 were among the largest and most damaging recorded along the U.S. waterway in the past century, comparable in extent to the Great Mississippi Flood of 1927 and Great Flood of 1993. In April 2011, two large storm systems deposited record levels of rainfall on the Mississippi River drainage basin. When that additional water combined with the springtime snowmelt, the river and many of its tributaries began to swell to record levels by the beginning of May. Flooding occurred in Illinois, Missouri, Kentucky, Tennessee, Arkansas, Mississippi, and Louisiana.
The project design flood is a hypothetical "maximum probable" flood of the Mississippi River used by the United States Army Corps of Engineers to aid in the design and execution of flood protection in the Mississippi Valley.
The West Atchafalaya Floodway is a flood control structure of the Mississippi River and Tributaries Project located in the Lower Atchafalaya Basin in south-central Louisiana. It has a project design flood flow capacity of 250,000 cu ft/s (7,100 m3/s).
Louisiana State Route 7 was one of the 98 original state highways that were established in 1924. It was split into two separate segments, with the western section running in a west to east direction for 110.80 miles (178.32 km), spanning from Deweyville to the Atchafalaya River. The eastern section ran for 144.50 miles (232.55 km) from Lottie to the Mississippi state line, in a west to east direction.
Climate change in Louisiana encompasses the effects of climate change, attributed to man-made increases in atmospheric carbon dioxide, in the U.S. state of Louisiana.
Flooding in the Mississippi River Basin during the winter, spring, and summer of 2019 caused at least 12 deaths and economic losses in 19 states totaling in excess of $20 billion. Estimated damages in the Midwestern United States alone had reached $12.5 billion by April 2019. Flood damages totaling $6.2 billion were reported in the 11 states bordering the Mississippi River. In addition to property and crop losses and infrastructure damages, commercial navigation on the Mississippi River was interrupted repeatedly by high currents, low bridge clearances, and closed locks. This delayed shipments of agricultural commodities, adding to the economic stress of crop losses caused by flooding. As of late April 2019, shipments of corn to export terminals in Louisiana were 31% lower than in same period in 2018.