There were barges on the Mississippi River before the Civil War, but they weren't the massive ones we see today. My understanding is that most of the power transport on the river was in steamboats of the sort familiar to us from Mark Twain or
Showboat or Disneyland. Pilots had to point out shoals and snags and guide the ships around them.
It was only after the Civil War, after more work was done to the river, that massive barge transport took over. For some places, this only happened long after the Civil War was over. Channels had to be dug, snags removed, and on the upper river, locks had to be built. Similar work was done on the Ohio, the Missouri, the Tennessee, the Cumberland, the Arkansas, and other rivers.
P.S. The graphic comes from a site that is lobbying against more locks being built and other work being done to the river. If some people today had had their way in the past, much of the Mississippi would probably still be unnavigable for barges carrying large cargoes. The heavy volume of river traffic hasn't benefitted cities and towns that weren't able to upgrade their own ports, though. River traffic was a lot less in the 19th century, but towns like Cairo were better off than now.
In any case, midwestern farmers would still have been shipping much of their crop to large Eastern cities by train, because that's where the customers were.
As usual for you, x, your posting is intentionally misleading. Regardless of your misdirection, here for you is the strength of the Mississippi and the source of fear of the Northern business interests:
Before the beginning of the war, the South grew 60 percent of the world’s cotton, provided over half of all U.S. export earnings, and furnished 70 percent of the cotton consumed by the British textile industry. Cotton exports paid for a substantial share of the capital and technology that laid the basis for America’s industrial revolution.
All of this began in the years from the Louisiana Purchase to the 1850s, which were golden ones for the deep South, witnessing intense growth and development, and significant changes in the internal structure of its economy.
The North America continent’s interior was drained by a single river system—the Mississippi. From the Great Lakes to the Gulf of Mexico, from the Rockies to the Appalachians, the Mississippi with its vast network of tributaries, particularly the Ohio and Missouri Rivers, provided a natural waterway system for moving people and goods across the midcontinent of North America and down the Mississippi to its outlet on the Gulf.
Any city so strategically situated at the mouth of so splendid a transportation system would control the trade between the vast interior of North America and the rest of the world; and a city in so strange a situation might even determine the political future of North America.
These facts were as obvious to seventeenth century French explorers as they were to Thomas Jefferson, who said of New Orleans: “There is one spot on the globe, the possessor of which is our natural and habitual enemy. It is New Orleans.”
Aiding this process was the completion of the Erie and other canals in the 1820’s and 1830’s which drained away much of the upper Midwest grain trade. But, the railroad did not yet threaten the city's cotton business. The 1850’s were the high-water marks of cotton shipping, cotton culture, and cotton wealth in the nineteenth century deep South.
In terms of trade, between 1821 and 1835, the average total of exports and imports per year through New Orleans was $22 million ($15 million exports, and $7 million imports), a fourfold increase in exports alone. The exports represented for the period 1821-35 about 18% of all United States exports, and for 1852-60, 30% of the same.
Cotton shipment peaked during the 1860-61 season, totaling over 2,200,000 bales, worth $110,000,000 and representing 60% of the value of all products received from the upcountry. Sugar and tobacco were distant runners-up to cotton, and foodstuffs made up the bulk of the rest of the exports.
Most of the cotton was shipped from New Orleans to Liverpool and other British ports, either directly, or by transshipment through New York. New Orleans, then, was a transshipment point for cotton, and the city never developed into a major manufacturing center for the primary products it transshipped, financed or stored.
Cotton was the sinews of business in Ante-bellum Southern ports, such as Charleston, Savannah, Mobile, and Biloxi, the economic rhythms of the cities revolving around the cotton seasons. Cotton was picked and baled from September through December. Shipments into the cities ran from a low in October to a high in January, tapering off in the spring, with most of a year's crop exported by May.
In summer, the ports were virtually deserted as the heat, humidity, and falling water levels slowed dock workers, rotted any agricultural products on the docks, and hindered the river traffic. Many merchants and their families left the port cities to avoid the heat, yellow fever, cholera, and hurricanes. However, between January and March, many plantation owners and their families would visit in the cities, partaking of the social whirl of Mardi Gras, shopping, and meeting with their cotton factors, who acted as agents, bankers, and financial advisors.
On the Mississippi, the increased output of cotton was borne by a new, more efficient means of water transportation — the steamboat. The first steamboat came downriver to New Orleans in 1812. In 1821, 287 steamboats arrived in New Orleans; by 1826, there were 700 steamboat arrivals. In 1845, 2,500 steamboats were recorded, and during the 1850s an average of 3,000 steamboats a year called at the city. After 1830, then, steamboats were in general use on the Mississippi, allowing two-way packet lines to operate, carrying both cargo and passengers on regular schedules. Flatbed boats, which were once the main river vessels, virtually disappeared after 1857.
By 1860, New Orleans had a fledgling ship building industry, with machine shops, ironworks, and several shipbuilding firms, located mainly on the west bank in Algiers. Algiers also supported a dry dock and a ship repair industry, so that in all, over 500 men were employed in ship repair and building by 1861.
From 1810 to 1860, not just shipping and storage, but wholesale trade, entertainment, travel services, and finance boomed. Wholesale trade developed naturally as the city and its hinterlands, which until Chicago and St. Louis emerged included most of the Midwest, grew. New Orleans was the nearest distribution center for the upriver and inland communities of the Mississippi Valley for most of the period. In the 1850’s, St. Louis, the closest rival wholesale center, was far behind New Orleans and mainly oriented westward. New Orleans’ fast growing population also provided an increasing market for her thriving wholesale business.
Retail trade, too, benefited from a growing market of wage earners, renters, and plantation owners, whose income and wealth, new and old, supported a multiplicity of retail shops and artisans. New Orleans's close contacts with Europe, both in trade and in visitors, made for a cosmopolitan atmosphere that made shopping in New Orleans an international experience. D.H. Holmes, Maison Blanche, Werleins, and other modern retailers trace their histories to the boom times of the 1830’s, 40’s, and 50’s.
During the Pre-Civil War period, a scarcity of capital in New Orleans forced seekers of large-scale investment to look to New York, London, or Paris. New Orleans merchants were critical sources of credit for planters who borrowed in the spring and repaid in the winter from crop sales; but the merchants and their banks received credit from the New York or Liverpool cotton shipping and manufacturing interests.
With the cotton boom, New Orleans became the banking and financial center for the lower Mississippi Valley.
All major forms of national and international credit were in use in the city.