Breakdown: EWWW! Why the Mississippi River water is brown

Published: Jan. 29, 2020 at 3:25 PM CST
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MEMPHIS, Tenn. (WMC) - Have you ever driven past or walked along the Mississippi River and wondered what gives it that specific, brownish color?

The Mississippi River can appear muddy and brown depending on where you view it. According to experts, the Mississippi River is clean and clearer the further north you go. The River’s color and quality of the water can change quickly as it flows south through farmland and urban areas, according to experts.

As the Mississippi River snakes past St. Cloud and the Twin Cities and eventually flows south into the Gulf of Mexico, it often appears brown or yellowish and is sometimes referred to as the Muddy Mississippi.

It may be hard to believe but the color is not due to pollution but because of the sediment. The Mississippi River carries roughly 500 million tons of sediment into the Gulf of Mexico each year. The Mississippi River is not the only river with the brownish hue. The color is due to the sediments like, fine particles of sand, silt, clay, along with other materials found in the water.

The Minnesota River also carries a lot of sediment. The sediment runs off from farm fields and or washes into the river from eroding stream banks. Experts believe that that about three-fourths of the sediment in the Mississippi River in the southern part of the state came from the Minnesota River. The Minnesota River empties out into the Mississippi River. Some of the sediment that the Mississippi River carries and its color derives from some of the particles from the Missouri. According to experts the true Big Muddy is the Missouri River. Its nickname is because of the rich silt which carry the sediments of the western and mid western deserts, prairies and mountains.

The enormous amount of mud is first found above St. Louis where the smaller Missouri joins the Upper Mississippi and together they flow downstream through St. Louis to Cairo as the Middle Mississippi. Even though the Missouri is the smaller volume of the two rivers, its muddy water colors overwhelm the darker & clearer colors of the bigger Upper Mississippi, and together they finally combine as a muddy brown river, in essence an expression of the colors of the Missouri. Over a 150 miles further downstream, the Ohio flows in from the east to join the muddy Mississippi. When the rivers collide the resultant color is brown although the prodiment hue of the Ohio is a greenish hue.

Experts say that the color of a river doesn’t necessarily indicate whether it’s polluted or not. Some of the pollutants that concern scientists can’t be seen with the naked eye, meaning that just because a river is clear doesn’t mean it’s clean.

On the other hand, if a river is muddy or murky, it probably means there’s more in the water than just sand or soil.

Every year, excess nitrogen and other nutrients from the Mississippi River form a dead zone roughly the size of New Jersey in the Gulf of Mexico where oxygen levels are too low to support marine life.

Experts warn that just because a river is clear, doesn’t mean it’s clean. Rivers with clear water, have also been known to have pollution issues. Sometimes a river’s color is caused by geological conditions, or the type of rock or minerals it flows through. That’s why some rivers look bright blue or orange.

The Mississippi River carries roughly 500 million tons of sediment into the Gulf of Mexico each year.