Overview of Mississippi River
The Mississippi River is one of the longest rivers in the world, flowing over 2,340 miles from the northern Great Lakes to the Gulf of Mexico. Along with its major tributary, the Missouri River, the Mississippi serves as a vital drainage basin for 41% of the continental United States. Throughout time, it has been a major source of transportation, agriculture, and energy. The river is home to hundreds of species of animals, plants, and trees, as well as aquatic and migratory birds.
The great waterway also serves as the border between 10 states. The states of Minnesota, Wisconsin, and Illinois provide the upper headwater streams, while the Ohio River provides the northern border of the lower Mississippi River. The states of Arkansas, Mississippi, Tennessee, Kentucky, Missouri, and Louisiana form the southern border, known as the Old River Control Complex.
From its headwaters in the North to below the fall line at Cairo, Illinois, the Mississippi is recognized for its swift current. Its average velocity ranges from 1.2 to 5.2 miles per hour, with maximum velocities of up to 10.5 mph registered at certain points along the river.
Hydrology
The flow of the Mississippi River is incredibly dynamic. It can rise and fall from 25 to almost 200 feet in a single day, depending on the amount of precipitation, riverbank erosion, upstream reservoir control, and even the ocean’s tide. The river’s rate of flow is often unpredictable, leading to flooding and subsequent evacuations.
The vast watershed area of the Mississippi River also has an influence on the river’s speed. Spanning approximately 1.2 million square kilometers, the watershed includes small and large rivers, streams, creeks, and even portions of 25 states. All these water sources coupled with their snowmelt and runoff, ultimately contribute to the river in the form of precipitation.
Over the course of its length and while fed by disparate water tributaries, the density of the water bodies colliding with each other is sure to create numerous eddies and pools, leading to abrupt changes in pace and speed. Since faster moving water tends to stay on the outside of bends and slower water on the inside, the Mississippi River fluctuates between fast and slow currents along its way towards the Gulf.
Man-made Influences
Man-made influences can further impact the river’s speed, by either increasing or decreasing its velocity. Numerous hydroelectric and flood control dams are currently using the flow of the Mississippi River, helping regulate the water supply through the area and create controlled reservoirs of water. By changing the amount of water flowing downstream or by decreasing the river’s environmental impact, it is possible to reduce or regulate the speed of the river.
The presence of agricultural runoff or water pollutants can also have an effect on the speed of the Mississippi. Pollutants, such as fertilizers and chemicals, can cause an increase in algae and aquatic infestation, leading to additional drag and a decrease in the river’s speed.
The construction of levees and other riverbank modifications can also create obstructions and thus lead to slower speeds. Along the lower Mississippi River, these controls have impacted the speed of the current, to the point where it is sometimes slowing to a crawl, in comparison to its velocity in the northern reaches.
Commerce of the Mississippi
The Mississippi River also serves a commercial purpose. Significant portions of the transportation of bulk commodities, including grain, oil, and coal, take place on the river. The cost-effective transportation services of the river have attracted numerous companies to take advantage of the opportunities that it offers, leading to a significant impact on the regional economy.
The fast flowing water of the upper sections of the Mississippi is particularly beneficial for transport vessels. Cargo barges utilize this fast-moving current, minimize their fuel consumption, and still make an efficient service. The rapid flow also allows barges to make trips that otherwise would take many times as long, by covering long distances in shorter periods of time.
Environmental Impact of Fast River Current
The environment of the Mississippi River is largely shaped by the fast current found in the upper sections of the river. Due to the high flow rate, a healthy sediment load is maintained, keeping the riverbed fertile and free of expensive dredging. The great force of this fast-flowing water is also greater than its opposite, allowing it to erode and excavate the riverbed away as it flows. This characteristic gives the landscape a unique but noticeable form, featuring numerous oxbow lakes, sandbars, and shallow water depths near the steep banks of the river.
Stretches of Fast and Slow Currents
The speed of the Mississippi River varies greatly along the length of its expanse. The upper sections of the river, from its sources in the Great Lakes region to Cairo, Illinois, feature the fastest rate of flow, ranging from 2 to 5.2 mph. From Cairo to the Arkansas-Mississippi border, the river slows down somewhat to an average speed of 1.2 to 2 mph.
In Louisiana and points south, the Mississippi River creeps along with a speed of only 0.4 miles to 1.2mph. The draw of a greater amount of run-off, high agricultural runoff, and other pollutants coupled with the slower-flowing Old River Controls, create an effective dam, trapping both the flow and pace of the river.
The Role of the USACE
The U.S. Army Corps of Engineers is largely responsible for managing the Mississippi River. Their mission is to provide reliable navigation and protect against flooding, while still maintaining a careful balance between flood risk control, navigation, hydropower, recreation, water supply, water quality, and wetlands management.
In pursuit of their goals and objectives, the USACE regulates the flow of the Mississippi, with the primary objectives of preventing flooding and erosion, and providing the necessary water for commercial navigation. The Corps is therefore instrumental in maintaining the average speed of the Mississippi, notably allocating the proper amount of water for irrigation, power production, or for recreation.
The Significance of the Mississippi
The Mississippi River and its fast-flowing water deeply impact the lives of many throughout the region. From its impressive range of wildlife and vegetation, to local communities and commerce, the Mississippi River is a great source of natural resource and economic wealth, utilizing its immense power and speed to the benefit of all.
In the face of complex and ever-changing climate conditions, the Mississippi River stands as a symbol of strength and resilience, proving itself an integral part of the regional economy, environment and lifestyle.
