The view of flooded northwest Iowa, as seen from the helicopter carrying Iowa Gov. Kim Reynolds and members of her cabinet, who viewed the damage from the air on June 21. Photo courtesy of Gov. Kim Reynolds’ office via Iowa Capital Dispatch

For Louisianans, the devastating flooding along the upper Mississippi River will likely send some needed water downstream, and significantly lessen worries about summer drought on the lower Mississippi, according to meteorologists. 

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. 

The rain’s effects will ripple far from the river, said Mitch Reynolds, mayor of La Crosse, Wisconsin. “We just pulled out of a 16-month drought that cost our nation $26 billion,” said Reynolds, co-chair of the Mississippi River Cities and Towns Initiative (MRCTI), whose members have been keeping a close eye on how flooding in states like Iowa, Illinois and Missouri will affect downstream communities.

Wolverton and Reynolds spoke during a Thursday press conference hosted by a group of mayors from cities and towns along the Mississippi River basin, where forecasters and officials discussed the benefits and challenges of the heavy rainfall that hit the Midwest in June and July. 

“This rainfall is keeping the water levels up. Really, this is a good thing for the lower Miss,” Wolverton said. The current flood crest is moving through southern Iowa to central Illinois and northern Missouri. 

But the river is long and winding and a lot of water will soak into land along its banks, as it flows south. In coming weeks, the Mississippi River gauges near the city of New Orleans are not expected to rise much, despite the higher upstream waters, forecasters said. And by September, the entire river will drop back to normal levels, Wolverton said.

The flooding is expected to provide welcome relief to Louisiana and other 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. 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. Credit: La’Shance Perry, The Lens

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.

To casual observers, the added water would seem to eliminate the chances of dense saltwater creeping up the river as quickly as last year, when the saltwater wedge threatened drinking water for thousands. 

And with the current water levels, Roberts is not super concerned about the saltwater wedge. But that could definitely change, she said.  

Her tentative response is due to a broader picture, of all rivers within the entire Mississippi River watershed. Not all waterways are at high levels.

For instance, 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. 

Rainfall in the upper Mississippi basin and Ohio Valley drive river levels down south, Roberts said.

The higher water levels could also help keep invasive algae species at bay, according to Colin Wellenkamp, the executive director of MRCTI. Higher temperatures and lower water allow invasive algae to creep into the river from the Gulf of Mexico. 

Though these invasive algae come to the river from the Gulf, they flourish in the Gulf because  of nutrient runoff from fertilizers used in the upper river basin. 

Some algae species are already in the river, which can lead to increasingly frequent algal blooms that release toxins, threatening river fish and wildlife. “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.