Fish passage project: A first of its kind

More than a century ago, Robert Coker traveled to Keokuk on a cold, windy day in late April. A scientist at the U.S. Bureau of Fisheries Biological Laboratory at Fairport, Iowa, Coker had come to examine conditions at what was known then as the Keokuk Dam.

The dam and hydropower project, an engineering marvel that harnessed the powerful river currents for electricity, had been completed in 1913. And as Coker noted, within a few weeks of the dam closing, observers reported that fish were seen below the dam “in such numbers that local residents captured them not only with hook and line but with dip nets and hayforks.”

Coker, a prominent researcher in the field of zoology, was especially interested in herring, and when a local man informed him by mail of their appearance in mid-April of 1914, Coker made the trek to Keokuk.

There, below the dam, the herring could be seen in large numbers. “Such a close aggregation of fish can rarely be seen in fresh water,” Coker wrote in a report. “They had evidently followed up along the outer edge of the tailrace until they could go no farther.”

It was here that the first blocked fish migration in the Mississippi River was documented.

Experts have long observed the migration of fish is disrupted by locks and dams. And in the Mississippi River, mostly in the 1930s and ‘40s, there were 29 such locks and dams built.

Now, nearly 110 years after Coker first documented the herring’s difficulty making it past the Keokuk Dam, the federal government is preparing for the construction of a fish passageway, the first of its kind on the Mississippi River, which US Army Corps of Engineers officials expect will restore a connection for fish migration and also create a laboratory in which to learn and adapt future passageways up and down the waterway.

The passageway to be built at Lock and Dam 22 near Saverton, Missouri, about a 30-mile drive south from Quincy, Ill., is one of five that were authorized by Congress in 2007 as part of the Navigation and Ecosystem Sustainability Program.

The NESP, as it’s known, is a dual-purpose initiative operated by the Corps that is aimed at improving not just navigation on the river but also the environment.

Like other NESP projects, however, the money to build the fish passageway has been waiting for years for Congressional approval.

The wait is now over — $97 million was approved as part of the $1 trillion infrastructure bill passed by Congress and signed into law in 2021.

The infrastructure law also is providing $732 million for a modernized, longer Lock 25 north of St. Louis.

The benefits of fish passage are incremental, according to a Corps report that was published in 2021. A group that studied the issue said “the systemic benefits of fish passage will not be realized until there is free fish movement through at least 18 specific Locks and Dams.”

Still, this is a significant initiative.

“This project is one of the larger ecosystem projects we will do of the ‘E’ in NESP,” says Andrew Goodall, regional program manager for the Navigation and Ecosystem Restoration Program.

The passageway is one of hundreds of ecosystem projects identified in a lengthy 2004 Corps of Engineers feasibility report that took a broad-based look at navigation and ecosystem needs on the Upper Mississippi River and Illinois Waterway system and presented a plan of action.

As the report noted nearly 20 years ago, the goal of the plan is to ensure the system “continues to be a nationally treasured ecological resource as well as an efficient national transportation system.”

Congress’s authorization in 2007 approved about $1.7 billion in ecosystem projects, along with $2.2 billion in navigation improvements.

Mimicking the river

The fish passageway at Lock and Dam 22 will be notched out of the dam, with a 200-foot opening to allow the fish to pass through.

“It’s supposed to mimic the natural river system,” says Rachel Hawes, the ecosystem program manager for NESP.

Most of the passageway will be located underwater and consist of tiers, or smaller pools, that rise so fish can pass over rocks, rest, and then move up as they pass through. A debris boom will be built to prevent the passageway from getting blocked. There also will be a bridge, along with a research deck to house monitoring equipment.

In all, the cost of the passageway is estimated at $138 million, which will include funding for other construction and monitoring activities, as well as possible modifications, officials say. The rest of the money is expected to come through subsequent appropriations requests.

Hawes says there are a number of studies that are currently identified as part of the project: A study of fish movement through the fishway; monitoring the ecological response to the migration; monitoring the physical performance of the passageway features and ensuring that, based upon the information gathered, that the passageway is performing at its optimum.

That learning process is already going on. Experts are studying how passageways are built along with the best techniques for fish to migrate. They’re also developing models on how the fish might react to the passageway.

“We already today understand so much more about fish passage in the upper Mississippi River than we did 10 years ago because we started this process,” says Mark Cornish, a senior technical specialist and fisheries biologist with the Corps.

Among the activities is to extensively monitor current fish movements. The Corps has tagged more than 500 fish of different varieties to track their movement, using listening devices in the water.

“It’s just absolutely amazing how far these fish can move,” Cornish says. Some have moved thousands of miles.

An ancient species

Corps officials say the passageway project at Lock and Dam 22 is aimed at benefitting a large number of native species, including the Lake Sturgeon, White Bass and Northern Pike – and the Skipjack Herring.

Skipjack Herring, according to experts, once migrated in large schools to spawn on Lake Pepin and Lake St. Croix on the Wisconsin-Minnesota border. Now, however, they are restricted to below Lock and Dam 19.

Then, there is the Paddlefish.

The Paddlefish is a remarkable creature. Its rostrum (or bill) is shaped like a paddle; some liken it to a long-handled spoon. Its mouth is large, and its body made of cartilage rather than bone. Its eyes are small and its skin smooth. Found in large rivers and lakes, the Paddlefish is a survivor. It dates back more than 100 million years.

The Chinese Paddlefish, also a survivor since ancient times, was not so fortunate. It once inhabited the Yangtze River, but the construction of dams and overharvesting led to its decline beginning in the 1970s, and the last time it was seen was in 2003 when the Three Gorges Dam was built.

The species was declared extinct last year. Fortunately, the Paddlefish still exists in North America, but there is enough concern for its future that several states, as well as other entities, have undertaken special efforts to protect it.

“The Paddlefish is an ancient species that was swimming when the dinosaurs were around and now the last place on earth that you can find it is in our back yard,” Cornish says. “It’s that special.”

He adds that some Paddlefish from the main stem of the river have been found traveling as far away as Waterloo, Iowa, to spawn and then move back when conditions are right. However, the conditions have to be right. “The dams between them and their spawning grounds have to be open when they need to get through,” Cornish says.

“All the pieces have to be in place for them to have a successful spawn. If we can adjust one of those pieces, it increases the odds that they’ll have a successful spawn in the future. And that’s what our Lock and Dam 22 project does,” he adds.

Keeping out the carp

One of the challenges of the passageway project is invasive carp.

Even though the dams inhibit upriver movement of carp just as they do native fish, the invasive species nonetheless became established in the Mississippi River in the early 1980s, and their populations have increased over time.

The carp rival native population for food sources.

A fish passageway that allows native species to swim upriver also could open the door to more invasive carp. But the Corps said in a report for this project, “the risk of increasing the northern expansion of invasive carp is low, as they have been established in the Mississippi River for over twenty-five years and have steadily increased in abundance.”

The Corps noted that invasive carp have already established themselves upriver of Lock and Dam 22, and fish passage offers the chance to enhance native species so they can better compete with invasive species.

This project won’t get done overnight. The Corps says a construction award is expected in fiscal year 2024, with the passageway to be finished in fiscal year 2027 if all goes as expected.

The opportunities for research with this project are significant, Corps officials say. They are planning to work with universities to improve research and hands-on experiences so that people will better understand the project and the ecosystem.

Says Hawes: “We do want people to have access to a better understanding of this amazing system that they live right next to that they may not interact with on a daily basis … so that they can better appreciate the resource they have access to.”