COLUMBIA, Mo. (AP) - Historically, the pallid sturgeon made its home in the chutes, sloughs and side channels of the floodplain of the Missouri River.
The whiskered bottom feeder fed in turbid waters on smaller fish and aquatic insects.
When it was time to spawn, the fish braved rapid waters to travel hundreds of kilometers upstream, swimming to the grounds used by its ancestors in the Paleozoic Era.
This year, the few remaining pallid sturgeon in the Missouri River made the journey upstream to spawn as usual.
Then they hit a wall.
The fate of the pallid sturgeon is at the center of a debate involving environmentalists, farmers, navigators, politicians and lawyers.
For decades, the U.S. Army Corps of Engineers has grappled with how to save the endangered pallid sturgeon, which has had its habitat destroyed by the dams, levees and dikes built in the 20th century.
The situation has pitted sturgeon against settlers. On one hand, the fish need wild water to complete their life cycle. However, persistent flooding has required human intervention to tame the river.
Barriers were built to stop the floods, but they also stopped the fish.
About 15.5 million people, 1.4 million acres of farmland and $23.8 billion in residential property are now threatened by flooding in the Missouri River Basin. The flooding this year made that apparent, after at least 60 levees were overtopped or breached across Missouri and Kansas.
That means more attention has been directed to controlling the river to protect landowners - bad news for the pallid sturgeon.
The Corps has historically sided with landowners and favored flood control, but in the early 2000s, the federal agency made controversial changes to the way it managed the Missouri River to comply with requirements under the Endangered Species Act.
Some landowners along the river claim those changes - spring releases from dams, changing water levels in reservoirs and extensive habitat restoration work - contributed to flooding on the river in subsequent years.
In 2014, 372 business and landowners filed a lawsuit claiming the government essentially stole their land and gave it back to wildlife. The government had encouraged settlement in the river basin for decades, the landowners argued, but now it was de-prioritizing flood control in favor of wildlife management.
A federal judge determined last year the plaintiffs were right. The judge ruled the Corps' work to protect endangered and threatened species had contributed to flooding in 2007, 2008, 2010, 2013 and 2014.
Now, politicians are seeking to again make flood control the main priority on the Missouri River. Advocates for the sturgeon, meanwhile, are pushing back.
The pallid sturgeon, a large fish with a shovel-shaped snout and toothless mouth, was first identified as a distinct species in 1905, according to a 2016 report from the U.S. Geological Survey.
Evolved from an ancient group of bony fishes dominant during the Paleozoic Era, the pallid sturgeon is well-adapted to bottom feeding in the swift waters of muddy, free-flowing rivers.
Historically, the Missouri River and its floodplains provided such a habitat, but the river underwent dramatic changes as the U.S. population grew.
In the late 1800s and early 1900s, commercial fishermen heavily harvested all types of sturgeon for caviar and meat in the Missouri and Mississippi rivers. Meanwhile, the country's expansion westward led to levee and dam projects to turn the braided, unruly river into a navigational channel.
The levees cut off the Missouri River from its floodplains and made it run swifter and higher. Six dams built by the Corps from 1926-52 impeded spring flooding and made downstream water cooler and clearer, carrying less nutrient-rich organic material that the sturgeon depended upon.
In 1990, the pallid sturgeon was listed as endangered. Fish and Wildlife Service determined the primary cause for its population loss was structural modifications to the river.
Estimates of the current pallid sturgeon population are limited and subject to considerable uncertainty, according to the 2016 Geological Survey report.
A 1996 report summarizing the estimates of other research suggested as few as 6,000 to as many as 12,000 wild pallid sturgeon existed throughout their natural geographic range, essentially the Missouri, Ohio and Mississippi rivers. A 2012 report estimated 5,991 pallid sturgeon swam in the lower Missouri River.
Robert Jacobson, a supervisory research hydrologist for the U.S. Geological Survey, has spent decades studying the ecosystems of the Missouri River, including that of the pallid sturgeon.
Jacobson told the Columbia Missourian the changes to the river caused several problems for the pallid sturgeon.
Typically the fish would travel hundreds of kilometers upstream to spawn, then the river would carry the larvae hundreds of kilometers back downstream to supportive habitats.
However, researchers hypothesize the dams are stopping the fish from reaching their optimal spawning habitats. Since the river is running swifter than it has historically, the larvae are also being swept downstream so quickly they cannot escape the main channel and reach the nutrient-rich river banks, causing the larvae to starve.
Jacobson said the dams also disrupt the natural flow of the river. In its natural state, the river would flood in early and late spring due to increased rainfall and melting snow.
Researchers believed the flooding served as a "spawning cue" for the pallid sturgeon, a biological signal telling the fish to swim upstream.
The dams prevent that flooding and are likely impeding the fish's migration instincts, Jacobson said.
In the early 2000s, Fish and Wildlife Service issued two biological opinions calling for the Corps to develop a plan to protect the pallid sturgeon, as well as two birds - the threatened piping plover and the endangered least tern. The Corps' work on the river had removed sandbars used by the birds for nesting and raising their young.
The Corps also faced lawsuits from environmental groups for failing to protect wildlife. In 2003, a federal court ordered the Corps to update its master manual to reflect its current policies and practices for operations on the Missouri River.
Substantial changes were made to the way the Corps operated the Missouri River, as outlined in a 2004 master manual. Those changes became the center of the landowners' lawsuit 10 years later.
In the master manual, the government agency said it would implement "bi-modal spring pulsing" by March 2006. The master manual also called for "reservoir unbalancing" and physical alterations to river control structures.
Bi-modal spring pulsing is the intentional release of water from dams in early and late spring, meant to cue the pallid sturgeon to spawn and create sandbar habitats for the birds.
According the landowners' 2014 lawsuit, the Corps had acknowledged spring pulsing was a means "to operate the Missouri River system of dams and reservoirs to intentionally flood." Further, the agency had acknowledged in 2005 that the flooding of the river would have negative effects on the landowners downstream, but positive effects for the species.
Spring pulsing was controversial at the time, and the Corps faced pushback from landowners downstream. Jacobson said the Corps ultimately compromised so the rises were much smaller and less threatening to stakeholders.
Reservoir unbalancing cycled high and low water levels in its reservoirs during certain years, resulting in unbalanced volume in the reservoirs.
Jacobson said low water in some reservoirs was intended to expose shorelines for bird nesting, but landowners claimed it left less space for flood storage in other reservoirs.
The physical alterations to river control structures were intended to promote erosion and widen the river for wildlife habitats.
The government lowered wing dikes and revetments, structures that help stabilize the river banks. Engineers also notched hundreds of dikes, which caused further erosion of the banks, and created dozens of chutes along the channel to develop sandbar habitats for birds.
All these alterations to the river management plan reflected a philosophical shift for the Corps, the lawsuit states. No longer did the Corps declare in its master manual that its top priority was flood control; instead the goal was "flood-risk reduction," now one of eight priorities, including fish and wildlife, navigation and recreation.
In the lawsuit, 372 business and landowners in the Missouri River Basin claimed the combination of these changes led to increased flooding on the river in the years that followed, and, as a result, the government was unlawfully taking property from landowners, no different than if it took the property through an eminent domain action.
The case went into the first phase of trial in the U.S. Court of Federal Claims in 2017. In March 2018, Judge Nancy B. Firestone ruled in favor of the plaintiffs, determining that the Corps' changes to river management did increase levels of flooding in several years from 2007-14.
The trial is currently in its second phase, with parties trying to determine the amount of the damages.
A spokesperson for the Corps said it was the agency's policy not to comment on pending litigation.
The Corps removed bi-modal spring flooding and reservoir balancing from its master manual last year.
After flooding began in March, battering levees and destroying farmland, politicians have been calling for a change in the Corps' priorities.
Gov. Mike Parson wrote in a March 28 editorial the Corps needed to make flood control its main priority again, rather than one of eight competing interests.
"The Corps can, and needs to, improve the way it manages the system, but we as a state also need to take a stronger role in guiding the federal government's management of the Missouri River," the governor wrote. "Our citizens can't continue to risk their lives, homes, livestock, and futures on a flood-control system that is insufficient to protect them."
At a congressional hearing in April, Sen. Chuck Grassley, R-Iowa, echoed the governor's sentiments, specifically citing the federal judge's ruling in 2018.
"A little more Midwestern common sense might have protected local communities, millions of bushels of grain and the tens of thousands of acres of farmland," Grassley said.
Sen. Josh Hawley, R-Mo., introduced two bills to address the issue in May. One bill, the Missouri River Flood Control Prioritization Act, would require the Corps to make flood control management its highest priority on the Missouri River. It would also eliminate fish and wildlife as a priority. The second bill would create an advisory council to help the Corps figure out how to do that.
Tom Waters of the Missouri Levee and Drainage District Association said he supported Hawley's bill. He said he has noticed a "dramatic increase" in flooding since the Corps' began habitat restoration work.
The Corps needed to stop conducting "science experiments" to save wildlife, Waters said, and start prioritizing flood control again. He said a way to do that would be to ease regulations to allow levee district managers to build higher levees.
Lawyers for the landowners claim the Corps actions during the past 15 years contributed to this year's flooding, even if bi-modal spring pulsing and reservoir unbalancing stopped.
Seth Wright, an attorney for Polsinelli Law Firm, said in the Corps' 1979 master manual, flood control was listed as the agency's main priority. Wildlife management was last on the list. But in 2004, everything was made equal.
"Flood control today is a reactive priority," he said. "Flood control does not become the top priority until flooding is imminent."
By the time flooding is imminent, it's too late to do anything, Wright said.
On top of that, the Corps made thousands of changes to the river to preserve habitats, which continue to weaken flood control today, Wright said.
Though the landowners' lawsuit does not contemplate it, Wright said it would be possible to stop the Corps from making physical alterations to the river through an injunction.
Not everyone agrees the Corps is responsible for recent flooding.
Bill Beacom, a retired river boat captain from Sioux City, Iowa, is a member of the Missouri River Recovery Implementation Committee, which was established by Congress in 2007 to provide stakeholders in the Missouri River Basin a voice in river operations. He said he was also an early member of the Pallid Sturgeon Recovery Program.
He said the Corps was constantly in the crosshair for problems on the river, which was unfair.
"One of the biggest problem is they get blamed for everything," Beacom said. "They have jurisdiction, but no law-writing ability. If they do something that displeases the farmers, it's their fault."
Beacom said the flooding solution could not be solved by bigger levees. Though stakeholders might not want to hear it, the river needed a larger floodplain, which meant moving the levees back away from the river and expanding the channel.
He said everyone - farmers, conservationists and navigators - should compromise and share the pain.
"Anybody can criticize, but criticism without a solution is just blowing wind up someone's skirt," he said.
David Stokes, executive director of the Great Rivers Habitat Alliance, said the federal government spent hardly any money on wildlife conservation compared to flood mitigation on the Missouri River. The levee system itself, which lead to more commercial real estate development in the floodplain, was causing the flooding, not just on the Missouri River, but on rivers across the United States. Climate change was also contributing to it, he said.
"We are doing this to ourselves," he said. "Any bill to tell the Corps to only spend money on levees and flood control, and not to spend a tiny amount of money on wildlife, is wrong thinking."
Jacobson said the needs of flood risk reduction and habitat management could be balanced.
"Flood risk reduction and habitat management share a lot of common ground, but only if the river is given room to move," Jacobson said.
He said levee and drainage districts along most of the river built levees close to the river banks to maximize protected farmland. Moving those levees back from the natural river banks would produce an area of land that would provide wetland habitat, help reduce flood stages and have a modest effect on flood storage.
It would be expensive, however. Moving back the levees would mean purchasing productive farmland near the river. Those farms would also no longer contribute to the local tax base.