My hometown of Saint Paul, Minnesota is within the Mississippi River watershed. This basin covers 41% of the contiguous United States and is the 3rd largest in the world. Nearly 1 in 3 Americans live within this river watershed (Information About the Upper Mississippi River System). In the image below, you can see the Mississippi River with the skyline of downtown Saint Paul on the other side (and my dog).
Until 1803, when the Louisiana Purchase was signed, the Mississippi River was the border of the US with France. The Native American tribes used the Mississippi and the hundreds of other creeks and rivers in the watershed for fishing, trade, and personal movement. European settlement and the invention of the steamboat were the beginning of the river’s modification by humans (The Mississippi/Atchafalaya River Basin (MARB)). The U.S. Army Corps of Engineers constructed hundreds of dams to ensure at least a river depth of at least 4 feet, and then 9 feet in the 1930s.
These projects removed many of the Mississippi’s wide shallows, braided channels, and sandbars. Many levees were also built which separated the river from about 50% of its floodplain. In some areas of the watershed, farmers have sold their land because it is too costly to continue farming with the increase in floods. The river often floods cities it runs through, like Saint Paul or Saint Louis (Mapping the Mississippi).
By connecting Lake Michigan to the Illinois river with a canal, which ends up feeding into the Mississippi (Information About the Upper Mississippi River System). This means that anything in the Great Lakes watershed could make its way into the Mississippi river watershed. Scientists believe that barge traffic is responsible for bringing Zebra Mussels into the Mississippi river in exactly this way, first found in 1992 (Zebra Mussel). Efforts are being made to keep the Great Lakes watershed and Mississippi river watershed separate. There have not been any sea lamprey or goby found in the Mississippi and the Great Lakes are still free of invasive carp species (Crane). Various organizations work to monitor the Mississippi for invasive species and work to remove them if found.
Keeping the Mississippi river watershed healthy requires teamwork from federal, state, and county governments across 31 states and 2 Canadian provinces. There are also nonprofit conservation groups working with this watershed as well. One of the main efforts is to reduce non-point source pollution getting into the river. The nutrient and sediment levels in the river have dramatically increased with human activities and land use around the watershed. It is estimated that about 31% of the nutrients contributing to the Gulf of Mexico’s Dead Zone, come from the Mississippi river (Information About the Upper Mississippi River System. The City of Saint Paul manages 22 sampling sites along the river to test nutrient levels. They have found sources of nutrients like phosphorus and have been able to reduce the initial 80 mg of phosphorus /liter of water down to 20 mg/liter (Watershed Management and Reservoir Restoration Program). Programs like this have reduced problems within the watershed and will continue to improve the health of the Mississippi River.
Citations
Crane, Donna. “Invasive Species on the Move: The Great Lakes and Mississippi River Basins.” KQED, 1 Nov. 2011, https://www.kqed.org/quest/26322/invasive-species-on-the-move-the-great-lakes-and-mississippi-river-basins.
“Information about the Upper Mississippi River System.” Wisconsin DNR, https://dnr.wisconsin.gov/topic/Watersheds/basins/mississippi/aboutMississippi.html.
“Mapping the Mississippi.” The Nature Conservancy, 26 Mar. 2021, https://www.nature.org/en-us/about-us/where-we-work/priority-landscapes/mississippi-river-basin/mississippi-river-flooding-maps/.
“Watershed Protection & Restoration.” Saint Paul Minnesota, 6 Aug. 2019, https://www.stpaul.gov/watershed-protection-restoration.
“Zm Fact Sheet - Iowa Department of Natural Resources.” Iowa DNR, https://www.iowadnr.gov/Portals/idnr/uploads/fish/files/ZM%20Fact%20Sheet.pdf.
Hello Mia! When looking at a river as large and impactful as the Mississippi it is important to realize just how many smaller watersheds are feeding its source and how many states and programs are involved in its protection. It is interesting to hear that floods are a impact felt even in St. Paul, and I wonder how those floods or the built prevention structures that might exist, effect the ecology of environments in the St. Paul area.
ReplyDeleteHello Mia. You did an excellent job on the post! I found it interesting to learn how Minnesota's watershed have been impacted by the connection to other bodies of water. Would you recommend against connectivity of water bodies? You mentioned particularly how barge traffic and Great Lakes watershed being connected to Mississippi River watershed has led to bringing in zebra mussels. How else do you think we can avoid the introduction and spread of invasive species in other great lake watersheds?
ReplyDeleteHi Mia, lovely post, I really enjoyed reading about your experience with the Minnesotan stretch of the Mississippi Watershed. As a fellow Minnesotan from the Twin Cities area, I can attest to the high turbidity of the Mississippi around the cities. This is a direct result of the massive change of the rivers natural path, as well as the extremely high rates of human activity on and around the river. You are absolutely right to say that point source pollution is a major issue. However, I wonder how this can be changed, if at all? The cities being so densely populated and so relied upon for infrastructure for so many business, I wonder what the feasibility is to control all of that?
ReplyDeleteI really liked this post as it went in depth about how Minnesota, but other states have a pollution issue with the Mississippi River. Learning that it is such a large watershed was fascinating, but I understand the many issues that arise with this now based on your article. My article showed how even a small town can contribute to large pollution matters so I can imagine how a large city has a problem with this. However, I wonder if you think that Minnesota has a larger responsibility to not pollute this watershed since it is at the top of the river and impacts the rest of it as it flows down to the Gulf of Mexico?
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