Morgan City, Louisiana
Morgan City is a city in St. Mary Parish in the U. S. State of Louisiana; the population was 12,404 at the 2010 census. Morgan City sits on the banks of the Atchafalaya River; the town was named "Tiger Island" by surveyors appointed by U. S. Secretary of War John Calhoun, because of a particular type of wild cat seen in the area, it was changed for a time to "Brashear City," named after Walter Brashear, a prominent Kentucky physician who had purchased large tracts of land and acquired numerous sugar mills in the area. It was incorporated in 1860. During the American Civil War, the Star Fort of Fort Brashear was the larger of two works erected by the Union Army occupying the city to defend a Federal military depot and the town. During the Bayou Teche Campaign, on the night of June 22, 1863, 325 Confederates of Gen. A. A. Mouton's command, led by Major Sherod Hunter, landed their skiffs and flats in the rear of the town. Attacking the next day, they surprised and captured the city, taking 1,300 Union prisoners, 11 heavy siege guns, 2,500 stands of rifles, immense quantities of quartermaster and ordnance stores.
They captured 2,000 African Americans, between 200 and 300 wagons and tents, all while suffering losses of only 3 killed, 18 wounded. In 1876, the community's name was changed to Morgan City in tribute to Charles Morgan, a rail and steamship magnate who first dredged the Atchafalaya Bay Ship Channel to accommodate ocean-going vessels. On October 28, 1985, Hurricane Juan made landfall near Morgan City; the storm looped offshore and came onshore again in Alabama. On August 26, 1992, Hurricane Andrew came ashore 20 miles to the southwest of Morgan City. Andrew was the second most destructive hurricane in U. S. history, crossing Florida and regaining strength in the Gulf of Mexico before it struck Louisiana. A type of blackberry deemed the Youngberry was developed by B. M. Young in 1905 in Morgan City, as a hybrid between a variety of blackberries; the Youngberry is a cross between Luther Burbank’s, Phenomenal Berry, the Austin-Mayes Dewberry, a trailing blackberry. The Youngberry was introduced commercially in 1926 and came to rival Loganberries.
The Youngberry had excellent qualities, such as taste and high yields and it soon replaced the Loganberry of California. According to the United States Census Bureau, the city has a total area of 6.2 square miles, of which 6.0 square miles is land and 0.27 square miles, or 4.03%, is water. If the Mississippi River were to experience a major course change in the vicinity of the Old River Control Structure or Morganza Spillway, the main channel of the river would enter the Gulf of Mexico near Morgan City instead of New Orleans; as of the census of 2000, there were 12,703 people, 5,037 households, 3,394 families residing in the city. The population density was 2,166.5 people per square mile. There were 5,627 housing units at an average density of 959.7 per square mile. The racial makeup of the city was 71.28% White, 23.90% African American, 0.91% American Indian, 1.02% Asian, 0.01% Pacific Islander, 1.18% from other races, 1.69% from two or more races. Hispanic of any race were 3.37% of the population.
There were 5,037 households out of which 31.2% had children under the age of 18 living with them, 47.0% were married couples living together, 15.8% had a female householder with no husband present, 32.6% were non-families. 28.0% of all households were made up of individuals and 10.8% had someone living alone, 65 years of age or older. The average household size was 2.48 and the average family size was 3.04. In the city, the population was spread out with 26.4% under the age of 18, 8.7% from 18 to 24, 27.7% from 25 to 44, 23.3% from 45 to 64, 13.9% who were 65 years of age or older. The median age was 36 years. For every 100 females, there were 93.0 males. For every 100 females age 18 and over, there were 91.8 males. The median income for a household in the city was $28,324, the median income for a family was $36,196. Males had a median income of $31,712 versus $19,550 for females; the per capita income for the city was $14,577. About 17.7% of families and 20.7% of the population were below the poverty line, including 27.3% of those under age 18 and 17.7% of those age 65 or over.
St. Mary Parish School Board operates public schools: Morgan City High School Morgan City Junior High SchoolElementary schools: J. B. Maitland Elementary School M. E. Norman Elementary School M. D. Shannon Elementary School Wyandotte Elementary SchoolThere is a Catholic school, Central Catholic High School. Bill Burgo, baseball player Carla Blanchard Dartez, former state representative Charles deGravelles, Louisiana State Republican chairman from 1968–1972 Mo B. Dick, music producer Eddie Dyer, Major League Baseball player, St. Louis Cardinals pitcher Sid Gautreaux, baseball player Anthony Guarisco, Jr. state senator from 1976 to 1988.
New Orleans
New Orleans is a consolidated city-parish located along the Mississippi River in the southeastern region of the U. S. state of Louisiana. With an estimated population of 393,292 in 2017, it is the most populous city in Louisiana. A major port, New Orleans is considered an economic and commercial hub for the broader Gulf Coast region of the United States. New Orleans is world-renowned for its distinct music, Creole cuisine, unique dialect, its annual celebrations and festivals, most notably Mardi Gras; the historic heart of the city is the French Quarter, known for its French and Spanish Creole architecture and vibrant nightlife along Bourbon Street. The city has been described as the "most unique" in the United States, owing in large part to its cross-cultural and multilingual heritage. Founded in 1718 by French colonists, New Orleans was once the territorial capital of French Louisiana before being traded to the United States in the Louisiana Purchase of 1803. New Orleans in 1840 was the third-most populous city in the United States, it was the largest city in the American South from the Antebellum era until after World War II.
The city's location and flat elevation have made it vulnerable to flooding. State and federal authorities have installed a complex system of levees and drainage pumps in an effort to protect the city. New Orleans was affected by Hurricane Katrina in 2005, which resulted in flooding more than 80% of the city, thousands of deaths, so much displacement because of damaged communities and lost housing as to cause a population decline of over 50%. Since Katrina, major redevelopment efforts have led to a rebound in the city's population. Concerns about gentrification, new residents buying property in closely knit communities, displacement of longtime residents have been expressed; the city and Orleans Parish are coterminous. As of 2017, Orleans Parish is the third most-populous parish in Louisiana, behind East Baton Rouge Parish and neighboring Jefferson Parish; the city and parish are bounded by St. Tammany Parish and Lake Pontchartrain to the north, St. Bernard Parish and Lake Borgne to the east, Plaquemines Parish to the south, Jefferson Parish to the south and west.
The city anchors the larger New Orleans metropolitan area, which had an estimated population of 1,275,762 in 2017. It is the most populous metropolitan area in Louisiana and the 46th-most populated MSA in the United States; the city is named after the Duke of Orleans, who reigned as Regent for Louis XV from 1715 to 1723. It has many illustrative nicknames: Crescent City alludes to the course of the Lower Mississippi River around and through the city; the Big Easy was a reference by musicians in the early 20th century to the relative ease of finding work there. It may have originated in the Prohibition era, when the city was considered one big speakeasy due to the government's inability to control alcohol sales, in open violation of the 18th Amendment; the City that Care Forgot has been used since at least 1938, refers to the outwardly easy-going, carefree nature of the residents. La Nouvelle-Orléans was founded in the Spring of 1718 by the French Mississippi Company, under the direction of Jean-Baptiste Le Moyne de Bienville, on land inhabited by the Chitimacha.
It was named for Philippe II, Duke of Orléans, Regent of the Kingdom of France at the time. His title came from the French city of Orléans; the French colony was ceded to the Spanish Empire in the Treaty of Paris, following France's defeat by Great Britain in the Seven Years' War. During the American Revolutionary War, New Orleans was an important port for smuggling aid to the rebels, transporting military equipment and supplies up the Mississippi River. Beginning in the 1760s, Filipinos began to settle around New Orleans. Bernardo de Gálvez y Madrid, Count of Gálvez launched a southern campaign against the British from the city in 1779. Nueva Orleans remained under Spanish control until 1803, when it reverted to French rule. Nearly all of the surviving 18th-century architecture of the Vieux Carré dates from the Spanish period, notably excepting the Old Ursuline Convent. Napoleon sold Louisiana to the United States in the Louisiana Purchase in 1803. Thereafter, the city grew with influxes of Americans, French and Africans.
Immigrants were Irish, Germans and Italians. Major commodity crops of sugar and cotton were cultivated with slave labor on nearby large plantations. Thousands of refugees from the 1804 Haitian Revolution, both whites and free people of color, arrived in New Orleans. While Governor Claiborne and other officials wanted to keep out additional free black people, the French Creoles wanted to increase the French-speaking population; as more refugees were allowed into the Territory of Orleans, Haitian émigrés who had first gone to Cuba arrived. Many of the white Francophones had been deported by officials in Cuba in retaliation for Bonapartist schemes. Nearly 90 percent of these immigrants settled in New Orleans; the 1809 migration brought 2,731 whites, 3,102 free people of color, 3,226 slaves of African descent, doubling the city's population. The city became a greater proportion than Charleston, South Carolina's 53 percent. During the final campaign of the War of 1812, the British sent a force of 11,000 in a
Morganza Spillway
The Morganza Spillway or Morganza Control Structure is a flood-control structure in the U. S. state of Louisiana 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 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 2011 Mississippi River floods; the Great Mississippi Flood of 1927 was the most destructive river flood in the history of the United States, in large part due to the Mississippi River swelling to 80 miles wide in spots.
To prevent a repeat of the Great Flood of 1927, better control river flooding in general, Congress passed the Flood Control Act of 1928 to authorize the United States Army Corps of Engineers to build the Bonnet Carre Spillway, the Birds Point floodway in Missouri, the Morganza Floodway as part of the 1928 Mississippi River and Tributaries Project. Construction of the levees that make up part of the Morganza Spillway began in the late 1930s; the Morganza Control Structure portion of the project was completed in 1954 and subsequently became incorporated into the Mississippi River Commission's 1956 project design flood, which added the Old River Control Structure in 1963 to the protections used to prevent Mississippi River flood. The Flood Control Act of 1965 provided further regulation over the Morganza Spillway's role in Mississippi River flood prevention. A concrete pit called a stilling basin was added at the Morganza Spillway in 1977 "to provide erosion protection after the velocity of water pouring through the open bays during a 1973 flood caused severe scouring of the land behind the bays."
The Morganza Spillway, a 4,159-foot controlled spillway using a set of flood gates to control the volume of water entering the Morganza Floodway from the Mississippi River, consists of a concrete weir, two sluice gates, seventeen scour indicators, 125 gated openings which can allow up to 600,000 cubic feet per second of water to be diverted from the Mississippi River into the Atchafalaya Basin during major floods. The project was completed in 1954. A highway and the Kansas City Southern Railway cross the structure The Corps of Engineers maintains the structures and, in times of flood, monitors their piers for scouring and stability; the Corps of Engineers has two 25-ton cranes used to lower the flood gates. The cranes roll on special tracks next to the roadway, enabling the operators to open or shut any spillway gate or perform maintenance while the roadway is in use; the land on both sides of the Morganza Control Structure is above normal river water levels, dry. In order for water to reach the spillway, the Mississippi must first rise well above its flood stage, overtopping its banks.
The Corps of Engineers considers opening the Morganza Spillway when the flow of the Mississippi at Red River Landing, Louisiana, is greater than 1,500,000 cu ft/s and rising. Water from the Mississippi is diverted into the Atchafalaya Basin at only one place, the Old River Control Structure, in use since 1963, where floodgates are used to redirect the Mississippi's flow into the Atchafalaya River such that the volume of the two rivers is split 70%/30% as measured at the latitude of Red River Landing. During the 1973 Mississippi flood, the ORCS was being damaged due to high flow rates, leading to the opening of the Morganza Spillway to help relieve this pressure. Subsequently, the nearby Old River Control Auxiliary Structure was constructed, adding additional floodgates for use during major floods; the Morganza Spillway, about 30 miles downriver from ORCS and ORCAS, is designed for emergency use to divert additional water from the Mississippi River into the Morganza floodway, which merges downstream with the Atchafalaya floodway before entering the Gulf.
Diversion of water from the Mississippi's main channel has the effect of lowering water level in the Mississippi downstream of the spillway, helping to relieve stress on levees and other flood control structures both upstream and down. Besides controlling flooding in a given event, the system is designed to prevent the Mississippi River from permanently altering course down the Atchafalaya River, bypassing Baton Rouge and New Orleans. Water that passes the Morganza Spillway first enters the Morganza Floodway, which extends from the spillway at the Mississippi River south to the East Atchafalaya River levee; the floodway, 20 miles long and 5 miles wide, includes a stilling basin, an approach channel, an outlet channel, two guide levees. From there, diverted water enters the Atchafalaya River Basin Floodway near Krotz Springs and continues to the Gulf of Mexico. In an extreme flood event, a major release of water from the Morganza Spillway into the Morganza Floodway and Atchafalaya Basin inundates not only the floodways themselves, but extensive additional areas of southern Louisiana throughout the Atchafalaya Basin.
In such an event, the water level of the Mississippi, high enough to overtop the Spillway, would be flooding some areas in the Basin downstream of the
Wax Lake
Wax Lake was a lake in St. Mary Parish, Louisiana, converted into an outlet channel to divert water from the Atchafalaya River to the Gulf of Mexico; the Wax Lake outlet is an artificial channel, created by the United States Army Corps of Engineers in 1942 to divert 30 percent of the flow from the Atchafalaya River to the Gulf of Mexico and reduce flood stages at Morgan City, Louisiana. The project design flood flow capacity for the outlet is 440,000 cu ft/s; the Wax Lake Delta is a river delta in Louisiana, formed by rapid deposition of sediment following the creation of a canal through Wax Lake off of the Atchafalaya River in 1942. It is 20 miles southwest of Morgan City adjacent to the Atchafalaya delta, it receives 34 million tons of sediment per year. In the 64 years between 1941 and 2005, Wax Lake was filled with sediment, the delta prograded 8 km into the sea; the Wax Lake Delta's distributary channels form via deposition of mouth bars. The first branch to the west is Campground Pass and further south there are the three main branches, East Pass, Greg Pass and Main Pass.
The mid-channel is eroded and deposited downstream at the mouth of the river, which will create a new path of flow around it. There is an added deposition upstream, thus causing the river to bifurcate; this results in the familiar dendritic pattern. Because it was created during an observable period and, other than the creation of the canal, was not altered by humans, it has been in studies of deltaic formation. In the time since Hurricane Katrina, it has served and as a model for delta regrowth in the Mississippi River Delta region in order to restore habitat and protect against storm surge. Atchafalaya Basin
Louisiana
Louisiana is a state in the Deep South region of the South Central United States. It is the 25th most populous of the 50 United States. Louisiana is bordered by the state of Texas to the west, Arkansas to the north, Mississippi to the east, the Gulf of Mexico to the south. A large part of its eastern boundary is demarcated by the Mississippi River. Louisiana is the only U. S. state with political subdivisions termed parishes. The state's capital is Baton Rouge, its largest city is New Orleans. Much of the state's lands were formed from sediment washed down the Mississippi River, leaving enormous deltas and vast areas of coastal marsh and swamp; these contain a rich southern biota. There are many species of tree frogs, fish such as sturgeon and paddlefish. In more elevated areas, fire is a natural process in the landscape, has produced extensive areas of longleaf pine forest and wet savannas; these support an exceptionally large number of plant species, including many species of terrestrial orchids and carnivorous plants.
Louisiana has more Native American tribes than any other southern state, including four that are federally recognized, ten that are state recognized, four that have not received recognition. Some Louisiana urban environments have a multicultural, multilingual heritage, being so influenced by a mixture of 18th-century French, Spanish, Native American, African cultures that they are considered to be exceptional in the US. Before the American purchase of the territory in 1803, present-day Louisiana State had been both a French colony and for a brief period a Spanish one. In addition, colonists imported numerous African people as slaves in the 18th century. Many came from peoples of the same region of West Africa. In the post-Civil War environment, Anglo-Americans increased the pressure for Anglicization, in 1921, English was for a time made the sole language of instruction in Louisiana schools before a policy of multilingualism was revived in 1974. There has never been an official language in Louisiana, the state constitution enumerates "the right of the people to preserve and promote their respective historic and cultural origins."
Louisiana was named after Louis XIV, King of France from 1643 to 1715. When René-Robert Cavelier, Sieur de La Salle claimed the territory drained by the Mississippi River for France, he named it La Louisiane; the suffix -ana is a Latin suffix that can refer to "information relating to a particular individual, subject, or place." Thus Louis + ana carries the idea of "related to Louis." Once part of the French Colonial Empire, the Louisiana Territory stretched from present-day Mobile Bay to just north of the present-day Canada–United States border, including a small part of what is now the Canadian provinces of Alberta and Saskatchewan. The Gulf of Mexico did not exist 250 million years ago when there was but one supercontinent, Pangea; as Pangea split apart, the Atlantic Ocean and Gulf of Mexico opened. Louisiana developed, over millions of years, from water into land, from north to south; the oldest rocks are exposed in areas such as the Kisatchie National Forest. The oldest rocks date back to the early Cenozoic Era, some 60 million years ago.
The history of the formation of these rocks can be found in D. Spearing's Roadside Geology of Louisiana; the youngest parts of the state were formed during the last 12,000 years as successive deltas of the Mississippi River: the Maringouin, Teche, St. Bernard, the modern Mississippi, now the Atchafalaya; the sediments were carried from north to south by the Mississippi River. In between the Tertiary rocks of the north, the new sediments along the coast, is a vast belt known as the Pleistocene Terraces, their age and distribution can be related to the rise and fall of sea levels during past ice ages. In general, the northern terraces have had sufficient time for rivers to cut deep channels, while the newer terraces tend to be much flatter. Salt domes are found in Louisiana, their origin can be traced back to the early Gulf of Mexico, when the shallow ocean had high rates of evaporation. There are several hundred salt domes in the state. Salt domes are important not only as a source of salt. Louisiana is bordered to the west by Texas.
The state may properly be divided into two parts, the uplands of the north, the alluvial along the coast. The alluvial region includes low swamp lands, coastal marshlands and beaches, barrier islands that cover about 20,000 square miles; this area lies principally along the Gulf of Mexico and the Mississippi River, which traverses the state from north to south for a distance of about 600 mi ) and empties into the Gulf of Mexico. The breadth of the alluvial region along the Mississippi is from 10 to 60 miles, along the other rivers, the alluvial region averages about 10 miles across; the Mississippi River flows along a ridge formed by its own natural deposits, from which the lands decline toward a river beyond at an average fall of six feet per mile. The alluvial lands along other streams present similar features; the higher and contiguous hill lands of the north and northwestern part of the state have an area of more than 25,000 square miles. They consist of prairie and woodl
Mississippi River Delta
The Mississippi River Delta region is a three-million-acre area of land that stretches from Vermilion Bay on the west, to the Chandeleur Islands in the Gulf of Mexico on the southeastern coast of Louisiana. It is part of the Louisiana coastal plain, one of the largest areas of coastal wetlands in the United States; the Mississippi River Delta is the 7th largest river delta on Earth and is an important coastal region for the United States, containing more than 2.7 million acres of coastal wetlands and 37% of the estuarine marsh in the conterminous U. S; the coastal area is the nation's largest drainage basin and drains about 41% of the contiguous United States into the Gulf of Mexico at an average rate of 470,000 cubic feet per second. The modern Mississippi River Delta formed over the last 7,000 years as the Mississippi River deposited sand and silt along its banks and in adjacent basins; the Mississippi River Delta is a river-dominated delta system, influenced by the largest river in North America.
The shape of the current birdfoot delta reflects the dominance the river exudes over the other hydrologic and geologic processes at play in the northern Gulf of Mexico. Prior to the extensive leveeing of the Mississippi River that began in the 1930s, the river avulsed its course in search of a shorter route to the Gulf of Mexico every 1,000–1,500 years; the prehistoric and historic delta lobes of the Mississippi River Delta have influenced the formation of the Louisiana coastline and led to the creation of over four million acres of coastal wetlands. As the river changed course, the natural flow of freshwater and sediment changed as well, resulting in periods of land building and land loss in different areas of the delta; this process by which the river changes course is known as avulsion, or delta-switching, forms the variety of landscapes that make up the Mississippi River Delta. The Atchafalaya River is the largest distributary of the Mississippi River and is considered to be an influential part of the continual land-building processes within the Mississippi River Delta.
The river's tributary channel was formed 500 years ago and the Atchafalaya and Wax Lake deltas emerged around the middle of the twentieth century. Starting with the earliest European settlement, man has struggled with the delta's natural cycle of floods and transgression. Increased economic development and human habitation in the region created a desire to protect society from the threats posed by this mighty waterway. Beginning in the 20th century, advances in technology and engineering allowed humans to alter the river in fundamental ways. Although these changes shielded many people from danger and enabled significant economic development in the region, they have proven to have profoundly negative effects on the downstream delta; the formation of the Mississippi River Delta can be traced back to the late Cretaceous Period 100 million years ago, with the creation of the Mississippi embayment. The embayment began focusing sediment into the Gulf of Mexico, which facilitated the deltaic land-building processes for the future.
During the Paleogene Period, a series of smaller scale, regional rivers entered present-day southern Louisiana allowing an increase in dispersion of sediment deposition into the delta region. The Mississippi embayment became a primary focus of sediment deposition during the Miocene Epoch, which built the foundation of the modern delta region; the modern day Mississippi River Delta plain began to evolve during the Holocene Epoch due to the deceleration of sea level rise and the natural shifting of the river's course every 1,000–1,500 years. The delta cycle refers to a dynamic process whereby the river deposits sediment at its outfall, growing a delta lobe eventually, seeking a shorter path to the sea, abandons its previous course and associated delta. After the river changes course and abandons the delta headland, the region experiences land loss due to the processes of subsidence, erosion of the marsh shoreline, the natural redistribution of sands deposited along the delta that create the barrier islands.
The delta cycle contains the natural process of land loss and land gain, due to the directionality and discharge of the river. This process formed the bays, coastal wetlands, barrier islands that make up the coastline of Louisiana; the Mississippi River major deltaic cycle began over 7,000 years ago forming six delta complexes which are major depositional elements of a delta plain. The Mississippi River Delta complexes consist of smaller areas known as delta lobes, which contain the basins and other natural landscapes of the coastline; the six Mississippi River Delta complexes are as follows: 1. The Maringouin delta formed 7,500 to 5,500 years ago when relative sea level rose. 2. The Teche delta formed 5,500 to 3,500 years ago after relative sea level rise decelerated. 3. The St. Bernard delta formed 4,000 to 2,000 years ago following an avulsion that caused the river's relocation to the east of present-day New Orleans. 4. The Lafourche delta formed 2,500 to 500 years ago from a second avulsion that caused the river to relocate to the west of present-day New Orleans.
5. Modern day development formed the Plaquemines-Balize delta known as Bird's Foot Delta, between the St. Bernard and Lafourche delta. 6. Diversion to the Atchafalaya began 500 years ago with the Atchafalaya and Wax Lake Outlet deltas emerging in the mid-20th century. More recent influences created the most recent land building processes i
Old River Control Structure
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 leaving 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 Old River Control Structure is a complex containing the original low-sill and overbank structures, as well as the auxiliary structure, constructed after the low-sill structure was damaged during the Mississippi River Flood of 1973. The complex contains a navigation lock and the Sidney A. Murray Jr. Hydroelectric Station. Before the 15th century, the Red River and Mississippi River were separate and more or less parallel to one another. Beginning in the 15th century, the Mississippi River created a small, oxbow loop called Turnbull's Bend, near present-day Angola, Louisiana.
This loop intersected the Red River, making the downstream part of the Red River a distributary of the Mississippi. In the heyday of steamboats along the Mississippi River, it would take a boat several hours to travel the 20 miles of Turnbull's Bend, after which it would have progressed only about 1 mile from the entrance to the bend. To reduce travel time, Captain Henry M. Shreve, a river engineer and namesake of Shreveport, dug a canal in 1831 through the neck of Turnbull's Bend. At the next high water, the Mississippi roared through this channel; the upper portion of Turnbull's Bend became the smaller Upper Old River while the lower portion became the larger Lower Old River. At first, the Lower Old River would flow eastward, to the Mississippi, until 1839, when locals began removing a log jam, obstructing the Atchafalaya River; the project was finished in 1840. After that, the Lower Old River would flow eastward to the Mississippi when the Red River was high and the Mississippi was low, westward to the Atchafalaya when the Mississippi was high and the Red River was low.
Over time, the number of days when the river flowed east to the Mississippi decreased and the number of days when the river flowed west increased, until the Lower Old River flowed west over half the time. By 1880, it flowed eastward and was now capturing more and more of the flow of the Mississippi. With this extra intake of water, the channel of the Atchafalaya River was worn deeper and wider throughout the 1800s and early 1900s. Between 1850 and 1950, the flow increased from less than 10% of the Mississippi to 30%, the U. S. Army Corps of Engineers began work on the Old River Control Structure to prevent the Atchafalaya becoming the main channel of the Mississippi; the project was completed in 1963, it sealed off the Old river. However, a lock, a diversion channel, flood spillway were installed to allow barges to pass between the Atchafalaya and Mississippi; the U. S. Army Corps of Engineers measured the amount of water flowing through the Mississippi River and compared it to the amount entering the Atchafalaya Basin by monitoring "latitude flow" at the latitude of the Red River Landing, located five miles downstream of Old River.
In this case, latitude flow is a combination of the flows of the Mississippi and Atchafalaya rivers as they cross an imaginary line at that latitude. Between 1850 and 1950, the percentage of latitude flow entering the Atchafalaya River had increased from less than 10 percent to about 30 percent. By 1953, the U. S. Army Corps of Engineers concluded that the Mississippi River could change its course to the Atchafalaya River by 1990 if it were not controlled, since this alternative path to the Gulf of Mexico through the Atchafalaya River is much shorter and steeper; the Corps completed construction on the Old River Control Structure in 1963 to prevent the main channel flow of the Mississippi River from altering its current course to the Gulf of Mexico through the natural geologic process of avulsion. This natural process has occurred about every 1,000 years, is overdue; some researchers believe the likelihood of this event increases each year, despite artificial control efforts. If the Mississippi diverts its main channel to the Atchafalaya Basin and the Atchafalaya River, it would develop a new delta south of Morgan City in southern Louisiana reducing water flow to its present channel through Baton Rouge and New Orleans.
The Mississippi Flood of 1973 caused the control structure to fail. Integrity of the Old River Control Structure, the nearby Morganza Spillway, other levees in the area is essential to prevent such a diversion. Jeff Masters of Weather Underground noted that failure of that complex "would be a serious blow to the U. S. economy." The present Old River Control Structure was completed in 1964 and expanded in 1990. The first two floodgates are the Low Sill Control Structure, which regulates routine flow in the waterway, the Overbank Control Structure, in use only when the Mississippi exceeds its banks. A navigation channel and lock were part of the original facility design. Subsequent expansion created what is now known as the Old River Control Complex, when the Auxiliary Structure, which became operational in 1986, was added to reduce pressure on the original floodgates after extensive damage caused by the flood of 1973; the Sidney A. Murray Jr. Hydroelectric Station, completed in 1990 provides an additional measure of control at the site.
Water from the Mississippi is diverted into the Atchafalaya Basi
