In May, five conservation organizations—the National Wildlife Federation, American Rivers, Prairie Rivers Network, Missouri Coalition for the Environment and Great Rivers Habitat Alliance—filed suit against the Corps of Engineers in the Southern District of Illinois over its use of river training structures in the Middle Mississippi River, a 190-mile stretch between St. Louis, Mo, and Cairo, Ill.
The Corps won’t comment on ongoing litigation. But in a 2011 article, a Corps spokesman explained the several rationales for using river structures like bendway weirs, chevron dikes and revetments. Revetments armor riverbanks with rock against erosion, while the other two structures channel and focus water flow in specific directions for specific purposes.
One purpose about which the Corps has always been upfront is to scour the channel bottom to maintain a 9-foot navigation channel without as much need for dredging. “Dredging is expensive; there’s no way we could dredge the entire channel all the time,” said Eddie Brauer, who was a river engineer at the Corps’ Applied River Engineering Center in St. Louis in 2011.
But that’s not the only reason. Navigation safety is another justification, the Corps says. Bendway weirs and chevrons can redirect current in ways that make dangerous maneuvers like flanking safer for towboat captains and pilots.
The Corps says a secondary reason or collateral benefit from using these structures is creating or improving wildlife habitat. “The Middle Mississippi is a sand-bed river, which comparatively doesn’t have a great deal of biological diversity,” said Tom Keevin, who was biologist and chief of the Environmental Compliance Branch for the Corps in St. Louis in 2011. “When you put rock in [as in bendway weirs or chevrons], it creates a hard substrate in the river, which is habitat for bottom feeding invertebrates. It also provides a place for fish to go and feed.” The Middle Mississippi uses more of these structures than other sections of the river.
The habitat formation argument is familiar to a group of 372 landowners along the Missouri River. On March 13, 2018, Judge Nancy Firestone sided with those landowners in ruling that the Corps had deprioritized flood control along the Missouri River in order to promote habitat formation using those many of those same river structures, and was thus liable for increased flooding and its damages in 2007, 2008, 2010, 2013 and 2014. That ruling ended the liability phase of the trial; its compensation phase is ongoing. Initial estimates of potential damages were around $300 million. The Corps has already indicated it intends to appeal.
Unlike the Ideker Farms plaintiffs, who could only ask for dollar compensation, the five groups are challenging the Corps’ Supplemental Environmental Impact Statement for the Regulating Works Project, which guides the Corps’ management of this section of the Mississippi River. The plaintiffs insist they have no objection to any of the authorized purposes of the Corps, including navigation. But they argue that, contrary to what the Corps says, these structures degrade habitat and substantially increase flood risk, both downstream and upstream, in some cases by backing up water. They claim that river training structures always increase flood risk, no matter their purpose, and that the Corps ignores scientific studies that show this. The Corps claims their hydrologic studies show that once the structures are submerged or overtopped, they become “invisible” and have no effect of increasing floods.
How much should any of this matter to the towing industry? The plaintiffs say they are not attacking navigation, and support the maintenance of a 9-foot channel—just not by means of the structures. But if it’s true that some of these structures make navigation safer, it’s an issue of concern to towboaters.
We think the Corps does a good job of stewarding the river system, especially when Congress gives it enough resources to do so properly. Water transportation is the single most environmentally friendly mode and provides tremendous benefits to the nation in terms of reducing emissions from other sources.
If this trial is allowed to proceed, it could come down to dueling experts. Courts often give the Corps wide deference in its own areas of responsibility, especially when experts disagree. The plaintiffs are alleging specific harms and will have a lot to prove.