Overview
The Mississippi River is the second-longest in the United States and is made up of many majestic tributaries. It begins its course in Minnesota and runs through Wisconsin, Iowa, Illinois, Missouri, Kentucky, Tennessee, Arkansas, Mississippi, and Louisiana before emptying into the Gulf of Mexico. Spanning over 2,348 miles and winding through 11 different states, the Mississippi River is a major source of transportation, industry and recreation.
The Mississippi River and its tributaries are carried over by numerous bridges, of which there are five major types: suspension bridges, cable-stayed bridges, cantilever bridges, arch bridges, and truss bridges. Each bridge has unique characteristics and serves specific purposes, but how many Mississippi River bridges are there in total? To answer this question, let’s explore a little deeper.
The Number of Mississippi River Bridges
Currently, there are more than 600 bridges spanning the Mississippi River and its tributaries. This number changes, however, as new bridges are constructed and older ones are decommissioned. According to the U.S. Army Corps of Engineers’ Mississippi Valley Division, 502 of the bridges crossing the Mississippi River and its tributaries are owned by commercial entities, 198 are owned by states, and 104 are owned by local entities.
The number of bridges across the Mississippi River also varies from state to state. For example, there are 19 bridges connecting Illinois and Missouri on the Mississippi River, which is the most out of all states. Arkansas has the fewest bridges, with only three crossings the Mississippi. Some of the most popular crossings include the Rock Island Bridge, the Eads Bridge, and the Highway 82 Bridge.
Types of Bridges
The five main types of bridges crossing the Mississippi River are suspension bridges, cable-stayed bridges, cantilever bridges, arch bridges, and truss bridges. Each bridge is designed differently and serves specific purposes. For example, suspension bridges are designed to carry heavy loads and span the widest possible gap. Cable-stayed bridges are often used to cross shorter distances, while cantilever bridges are used when there are limitations on time and funds. Arch bridges are often preferred for their aesthetics, while truss bridges are often used for railway crossings.
Each bridge carries a unique history and holds a distinct importance within the respective communities. For example, the Rock Island Bridge, built in 1856, is the oldest surviving bridge on the Mississippi and the first to use suspender cables. The Eads Bridge was opened in 1874, is still the longest arch bridge in the world, and was one of the earliest bridges to use both steel and concrete. The Highway 82 Bridge is the longest bridge on the Mississippi River and spans over two and a half miles.
Environmental Impact
The construction of Mississippi River bridges has significantly impacted the environment. For example, a bridge’s width and height can act as a barrier to wildlife, some of which may need to travel across the Mississippi in order to complete their life cycles. Additionally, the lights on bridges affect the behavior of animals, potentially trapping them in areas that they would normally avoid. Bridge lights also have a negative impact on the health of nearby plant species, as they interrupt the natural cycles of light and darkness.
The pollutants that bridges release into the water can also have a negative effect on the environment. These pollutants include lead, arsenic, and mercury from paint, and antimony, nickel, and copper from metal components. The U.S. Environmental Protection Agency recommends testing for pollutants every three years to ensure that worksites are meeting standards.
Engineering and Maintenance
The engineering of Mississippi River bridges requires a team of experts to ensure the bridge is constructed safely and effectively. This includes bridge engineers, structural engineers, hydrologists, and geotechnical engineers. The engineers must consider the local environment, the expected loads, and the anticipated future traffic before designing a bridge. They are also expected to consider the economic impacts, the efficiency of the design, and the design longevity.
Bridge maintenance is also vital to ensure that bridges remain safe and functional. This includes regular inspections, repairs, and maintenance of the bridge structures, as well as the surrounding environment. The team of engineers must consider the expected loads, climate, and the surrounding environment before designing the maintenance plans. Such plans may include painting, crack repairs, waterproofing, and grout injection, among other tasks.
Significance of the Bridges
The Mississippi River Bridges are of significant importance in the United States. These bridges support the transportation of goods, services, and people across the Mississippi River and its tributaries, from one side of the country to the other. Additionally, the bridges help link communities on both sides of the river, creating new opportunities for tourism, industry, and recreation. Finally, the bridges contribute to the state’s economy by providing employment opportunities for the engineers, designers, and maintenance teams.
Political and Social Implications
The construction and maintenance of Mississippi River bridges have various political and social implications. Politically, these bridges help facilitate trade between the states and among countries, which in turn helps to boost the country’s economy. Socially, the bridges help to promote cultural solidarity, providing communities on both sides of the river with the opportunity to interact and build relationships.
The Mississippi River Bridges also support residential migration between states, allowing people to move from one side of the river to the other with ease. This, in turn, has served to break down many borders between states and create a more cohesive and connected nation. This movement of people has had a tremendous impact on the economy and culture of the entire region.
Safety Regulations
Safety is of paramount importance when it comes to Mississippi River Bridges. The bridges must meet certain load and design standards, which are outlined in the American Association of State Highway and Transportation Officials’ Bridge Design Specifications. Additionally, the bridges must be regularly inspected and maintained in order to ensure they remain safe and functional.
The Federal Highway Administration also assesses bridge safety and approves bridge projects. This organization is responsible for ensuring that bridges are constructed safely and effectively, and that existing bridges are regularly assessed for repairs and maintenance. The FHWA also helps to fund bridge projects and works to reduce the environmental impacts of bridge construction.
Conclusion and Analysis
Overall, there are more than 600 bridges currently spanning the Mississippi River and its tributaries, with the number changing regularly due to new bridge projects and decommissioning of older bridges. This number varies from state to state, with some states having as many as 19 bridges and as few as three. Additionally, five main types of bridges are commonly used to cross the river: suspension bridges, cable-stayed bridges, cantilever bridges, arch bridges, and truss bridges.
The bridges have had various impacts, both positive and negative, on the environment, the economy, and the cultural landscape. On the one hand, the bridges have helped to facilitate the movement of goods, services, and people across the Mississippi River, contributed to economic growth, and improved connections between communities on both sides of the river. On the other hand, they have released pollutants into the environment, caused light pollution, and disrupted the natural behaviors of certain wildlife species.
To ensure the bridges remain safe, federal, state, and local entities must take part in the design, engineering, and maintenance of the bridges. The bridges must also meet certain load and design standards, as outlined by the American Association of State Highway and Transportation Officials, and be regularly assessed for repairs and necessary maintenance. Only by following such protocols can the bridges remain functional and safe for years to come.
