The Mississippi River is Running Low, Again. It’s Not the Only One.

Photo by Bailey White via CNN

The Mississippi River, among the most important waterways for US trade, is running low… Again. Two consecutive years of drought conditions have brought the river to near-record lows, and according to AP News, there’s no clear end in sight. As of October 3, river levels near Memphis were about two feet lower than this time last year. Last month, the area reached an all-time low at 10.97 feet below average.

The Mississippi River is central to U.S. trade policy, particularly agriculture. In 2019, the river carried more than 500 million tons of imports, exports, and domestic freight. The river carries 60% of America’s grain exports and 78% of the world’s exports of feed grain and soy. Historically, low transportation prices along the Mississippi have kept American farmers competitive in the global market. With water levels dwindling, however, transport along the river is becoming more costly and logistically difficult. 

Due to the Mississippi’s low water levels, farmers are struggling to move their harvests down the Mississippi to access global markets. Barges carrying goods cannot be fully loaded without hitting the bottom of the river in its worst-hit stretches, forcing farmers to transport crops downriver by land to be loaded onto ships in areas where water is sufficiently deep. As a result, spot freight rates, or the price of moving goods along the river, in St. Louis have increased by 6% from last year and 115% from the previous three-year average. Thus far, projections suggest that reduced export costs and planning by the U.S. Army Corps of Engineers might be able to keep costs lower than they were last year. 

Economic damage is not the only danger of low water levels, however. 92% of U.S. agricultural exports are grown within the Mississippi watershed, or the area in which rainwater flows into the Mississippi. The Mississippi watershed spans 32 states. The basin also provides drinking water to nearly 20 million people.

Now, that drinking water is at risk. As a result of the Mississippi's historically low water levels, the flow at the mouth of the river is no longer strong enough to prevent salt water from the Gulf of Mexico from seeping upriver, endangering the water supply of tens of thousands. Salt water infiltration has a number of health impacts, including increased blood pressure. This can lead to increased risk of heart attack and stroke, particularly among the elderly. Pregnant women are also at risk of potentially deadly pre-eclampsia, and infants’ underdeveloped kidneys leave them at increased risk of high blood pressure as adults if exposed to salt water at a young age. Salt water can also corrode household appliances and pipes, including those made with lead.

Saltwater contamination of drinking water sources in Louisiana has prompted a wave of drinking water advisories in Louisiana. Some residents of Plaquemines Parish had been drinking and cooking with bottled water since June until their water advisory was lifted on October 18.

In order to push back the salt water, 10 inches of precipitation would have to fall across the entire Mississippi valley. Such heavy rainfall is not likely to happen until winter, well after the peak shipping season for farmers.

Thankfully, the U.S. has a number of tools at its disposal to mediate this decline in water levels. To maintain sufficient water levels for barges to pass, the Army Corps of Engineers routinely dredges the floor of the Mississippi river to remove sediment and debris. In more serious droughts, water can also be released from upstream reservoirs to supplement the Mississippi. However, neither of these solutions can last forever. Dredging is becoming increasingly frequent and labor intensive, and reservoirs are no more unlimited than the river itself.

Falling water levels in the Mississippi are a result of climate change. Historically, water levels this low occurred at most once every ten years. This summer was the hottest globally since record-taking began, and summer 2021 was the hottest in U.S. history. Eight of the ten hottest summers in U.S. history have taken place since the beginning of the 21st century. High temperatures push wet weather away from the southern and central United States, heightening the risk of drought events like this one.

The Mississippi isn’t the only water source at risk due to climate change, either. Many of the country’s most vital waterways are drying at an alarming rate: the Rio Grande and Colorado Rivers are shrinking by the day as the West has suffered two decades of “unusually hot and dry” weather. The Rio Grande, America’s fourth longest river, has run dry over one hundred miles.

The Mississippi is a warning sign to America that the climate crisis isn’t a distant, hypothetical future: it’s here. Our economy, our farmers, and even our drinking water are at an ever increasing risk as temperatures rise. As impressive as our water management techniques are, they cannot combat consistent drought forever. Instead, more attention must be paid to preventing further degradation of our water systems through sensible climate policy, particularly moving away from fossil fuels. Otherwise, drought events like this and other climate catastrophes will only become more common and severe.