July 16, 2024
Upstream flooding along the upper Mississippi may bring downstream benefits and alleviate summer drought, according to meteorologists.
A group of mayors and forecasters along the Mississippi River basin held a press conference on Thursday about the benefits and challenges of heavy rainfall in the Midwest in June and July. Representatives of the Mississippi River Cities and Towns Initiative (MRCTI) gave an update on how flooding in states like Iowa, Illinois and Missouri will affect downstream communities.
Anna Wolverton, a meteorologist with the National Weather Service, said the flooding was “a saving grace” for communities on the middle to lower portions of the river that have been stricken with drought over the past several years.
“This rainfall is keeping the water levels up. Really, this is a good thing for the lower Miss,” said Wolverton. She added that the current flood crest is moving through southern Iowa to central Illinois and northern Missouri. Wolverton anticipates that the river will drop back to normal levels by September.
“We just pulled out of a 16-month drought that cost our nation $26 billion,” said Mitch Reynolds, mayor of La Crosse, Wisconsin, and MRCTI co-chair.
The flooding is expected to provide relief to the lower Mississippi River states after the river experienced its lowest water levels for the second year in a row, according to a January 2024 report from the National Centers for Environmental Information. The flooding means that communities along the lower Mississippi River will likely not need to worry about low water until the dry season this fall.
According to the National Weather Service, the flood wave emerged this spring from an unexpected wet pattern in Minnesota, Iowa and South Dakota as thunderstorms pummeled the area. Remnants of Hurricane Beryl also brought an influx of extra rain.
A barge traverses the Mississippi River in southern Louisiana on June 7. Aerial support provided by SouthWings. photo provided by Iowa governor’s office
The flooding will keep the elevation of the river higher, for now. But much of the upstream water will likely be soaked up by the river banks before reaching Louisiana, said Amanda Roberts, senior hydrologist at the Lower Mississippi River Forecast Center of the National Weather Service.
“We’re really not seeing a significant change in our forecast,” said Roberts. “It looks like things will continue to slowly fall over the next several weeks.”
Communities in southeastern Louisiana can hope that the higher river levels and increase in tropical activity will stave off a third year of intense saltwater intrusion. The water from the Midwest will swell the river for several weeks, which could help keep dense saltwater from creeping up as quickly as last year, when it threatened drinking water for thousands.
With the current water levels, Roberts is not super concerned about the saltwater wedge. But that could definitely change, she added.
While the river level is high on the Mississippi, flows on the Ohio River are a bit below normal, said Karl Winters, hydrologist and surface water specialist for the United States Geological Survey. Roberts said that rainfall in the upper Mississippi basin and Ohio Valley drive river levels down south.
The higher water levels could also help keep invasive algae species at bay, according to Colin Wellenkamp with MRCTI. Higher temperatures and lower water allow invasive algae to creep into the river from the Gulf of Mexico. Higher waters in the lower Mississippi may prevent harmful algal blooms from entering the river.
“The invasive species situation in the Mississippi River continues to worsen over time, regardless of flood and drought,” said Wellenkamp.
This story is a product of the Mississippi River Basin Ag & Water Desk, an independent reporting network based at the University of Missouri in partnership with Report for America, with major funding from the Walton Family Foundation. MRCTI is also funded by Walton.