Soon after moving to this small town on the Potomac River, I noticed a door along the main street that bore the words “Eel Town Folk School.” I had no idea what it was, and the otherwise nondescript door offered no clues. But it sounded nature-loving and vaguely rebellious. I was intrigued.
“Eel Town,” it turns out, is a reference to the American eel, anguilla rostrata. For centuries or longer, it was a keystone species in this river and throughout (what we now call) the Eastern U.S. Through their various life stages, eels migrated across massive distances from spawning grounds in the Caribbean and up into tiny headwater streams, even wriggling onto land when necessary to complete the migrations.
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The local lore is that early colonizers called this place “Eel town” (or perhaps “Eel Pot”) because the indigenous people they displaced harvested so many eels from the river here. The astounding productiveness of river ecosystems in that era is difficult for us to comprehend today. And in that era of wild abundance, eels were especially abundant: pound for pound they represented about a quarter of all fish in Atlantic coastal streams and rivers.
Now they are essentially gone. A cryptic sign on a door is the only sign of them I can find in this place where once they were famously abundant. It makes me want to know why the eels disappeared. And whether they will ever return.
The answers take us further down the path we started on in Part I, where we asked how, concretely, we can act on the felt impulse to give to the ecosystems around us. While Part I looked at wildlife corridors, this part focuses on the river itself. The most important, immediate drivers of the eels’ decline, it turns out, are sitting right there in the river channel.
Returning life
For clues to what’s happened on the Potomac, we can look to the recent history of another major mid-Atlantic river artery, where eels are coming back. The Rappahannock River runs through Northern Virginia, roughly parallel to the Potomac River in places, a few dozen miles to the south. Its headwaters flow out of Shenandoah National Park. It then passes through mostly farmland—a lot of which is becoming exurban sprawl, particularly around Fredericksburg—before draining into the lower Chesapeake Bay.
Something extraordinary is happening on the Rappahannock. In 1994, the authorities razed and removed the Embrey Dam, a large hydroelectric dam built in 1910 (and which replaced an earlier dam erected in 1855). Suddenly, for the first time in 139 years, the Rappahannock River flowed freely over its entire 195-mile length.
The result? Over the next fifteen years, eel populations in the Rappahannock’s upstream reaches more than doubled. As eels returned to the Rappahannock watershed, they once again helped to cycle nutrients from ocean to mountains and back again. They now provide more food for osprey, raccoons, herons, striped bass, and many other species that prey on eels. They also have returned to their role as an important predator of smaller benthic fishes (those that dwell near the river or stream bottom). That effect likely benefits the benthic food web in yet unexamined ways, akin to how the reintroduction of wolves into Yellowstone enabled the reestablishment of streamside vegetation. Eels even help freshwater mussels—which attach themselves to eels in their larval stage—spread throughout the watershed, where they clean the water by filtering it. In short, returning eels infuse the Rappahannock watershed with new life and health.
“Half-way technologies”
Most Atlantic rivers today are not like the Rappahannock. They do not flow freely, and eels are not returning. The Potomac River, for example, has 443 dams, blocking migratory fish from access to 88 percent of the watershed. Dams have so altered the Potomac’s hydrology that much of the main stem is more lake than river, including the 3-mile “big slackwater” above dam number 4 near Shepherdstown and the “little slackwater” above dam number 5 near Williamsport. And the Potomac is typical. There are roughly two million dams in the United States. Across the country—and increasingly across the world—almost all major inland waterways are dammed.
Dams have coincided with precipitous declines in the populations of migratory fish. American shad, the world’s largest herring, was abundant beyond belief when the Eastern U.S. was colonized. Over 22 million were harvested from the Potomac River in 1832. Today the fishery is closed, and the population is at all-time lows. Most Eastern U.S. rivers once had salmon runs in the tens of thousands, shad runs in the millions, and river herring runs in the tens of millions. Today these populations are reduced by 95-99%, where they aren’t completely extirpated. Eel populations stand at less than one percent of historic levels.
Most efforts to restore migratory fish today focus on constructing “fish ladders” at dams, in combination with stocking rivers with fish spawned in hatcheries. But it’s not working. One study1 of mainstem dams with fish ladders on several rivers in the Eastern U.S.—the Merrimack, Connecticut, and Susquehanna—found that, on average, less than 3% of fish successfully surpass the mainstem dams. In a typical recent year, river herring passage at the first dam on each river was 706 fish, 86 fish, and 7 fish, respectively. After decades of work and hundreds of millions of dollars spent, populations are just a tiny fraction of restoration program goals. One detail stands out to me as grimly ironic: the third mainstem dam on the Merrimac River in New England is home to an educational center focused on migratory fish restoration, but in a typical year no anadromous2 fish successfully surpass that dam.
Relative to other fish, eels’ ability to leave the water and crawl limited distances over land may increase their success in traversing dams on the way upstream, depending on topography and other local conditions. But they encounter the same fatal bottleneck on the way back downstream: they are sucked into the turbines of hydroelectric dams and shredded.
I also learned from the paper cited above that fish passageways aren’t new. The first laws requiring their construction were enacted in the late 1700s, and major efforts to increase fish passage in Eastern U.S. rivers were made in the early 1900s and again in the 1960s. As the group of scientists concludes from their review of this long, depressing history, it may be “time to admit failure.”
To explain the failure at a deeper level and point the way to more promising solutions, these authors invoke the idea of “half-way technologies.” First coined in medicine, the term was used by wildlife ecologist Nat Frazer to describe conservation biology’s reliance on hatchery-raised turtles instead of addressing the underlying causes of sea turtle decline. These authors view fish passageways and hatchery fish releases as half-way technologies, and they think true recovery for migratory fish requires removing dams. To me the value of removing dams for migratory fish recovery seems indisputable. But I also think the term “half-way technology” obscures the real issue, implying that what’s needed is more technology—better information, better engineering, and more precise control. In fact, the promise of dam removal lies mainly in restoring the inherent capacity of rivers and ecosystems to heal.
Irreducible complexity
For me, the conclusion that successful river restoration requires empowering and supporting ecosystems—requires participation, not management—flows ineluctably from the complexity of the river ecosystems. For the more science learns about river ecology, the more complex it’s revealed to be. As summarized in another important scientific article, “The Natural Flow Regime,” the magnitude, frequency, duration, timing, and rate of change of river flows all influence river ecosystems, both directly and indirectly.3 To name just a few of the forms this influence can take: flows may determine seed dispersal, growth, and survival of plants; reproductive opportunities for insects and amphibians; and access by fish to floodplain wetlands. They even determine what nutrients are available in the water to feed microorganisms. And flow regimes are often synchronized with the life cycles of organisms, not just over the seasons of a year, but also in terms of interannual variability. When the natural flow regime is disrupted, ecological integrity declines. Usually this means the decline of specialized native species, adapted to a specific niche in an intricate web of relationships, in favor of generalist species, often non-native ones.
I see every reason to believe that this is playing out in myriad ways on the Potomac, whose mainstem dams have significantly altered its flows. One example, I suspect, involves the Eastern cottonwood. The cottonwood, a fast-growing, water-loving species, can get very large. Individual cottonwoods have been documented to be at or near the top of lists of largest trees in several Eastern states.4 The cottonwoods I’ve seen here along the Potomac River are likewise huge, with striking, deeply furrowed trunks. And I never see younger ones. So this jumped out at me when I saw it in the literature: “a certain rate of floodwater recession is critical to [cottonwood] seedling germination because seedling roots must remain connected to a receding water table as they grow downward.”5[6] Could it be that the giant cottonwoods I see near Brunswick germinated before the construction of mainstem dam 4 in the early 20th century, when the cycles of a more free-flowing river were still aligned with their needs?
The intricacies of the relationships between flow regimes and ecosystems are well summarized in “The Natural Flow Regime.” The authors acknowledge the difficulty of understanding the complex interactions of flow components and ecological processes with the reductionist methods of science and conclude that “a holistic view is necessary.” “[W]henever possible,” they say, “the natural river system should be allowed to repair and maintain itself.” But to me the lessons the authors do not take from their encounter with irreducible complexity are even more revealing. They ultimately endorse “enlightened river management,” rooted in better scientific understanding of flow regimes and refined environmental laws. In other words, they convincingly describe why river health depends on moving beyond the paradigm of control, then reaffirm that very paradigm.
The fealty of even the most clear-eyed scientists to the regime of scientific river management serves, despite their best intentions, to justify dams and the moribund rivers they “regulate.” It sustains the mistaken belief that we can destroy the natural flow regime and re-engineer it ourselves. In that sense, dams are not just a cause of the decline of river ecosystems. They are a symbol of our reigning sociocultural ideology, an embodiment of our choice to control instead of participate.
Back to Participation
Just as it points the way to dam removal, the recent history of the Rappahannock offers clues to a solution to the deep sociocultural obstacles to a thriving Potomac River. Because the Rappahannock isn’t returning to health solely through the management decisions of the United States and the Commonwealth of Virginia. It’s also an experiment in “Land Back”: returning land to the indigenous people those governments displaced.
What is it about empowering the Rappahannock Tribe that’s helpful for restoring a river to life and health? I am qualified only to ask that question, not answer it. So I offer the brief reflections that follow tentatively, in a spirit of humility, curiosity, and respect.
I suspect the answer is as broad as landscape and as deep as culture. The Potomac River before colonization was not just free-flowing within its main channels; it was utterly different. The history of Brunswick helps to paint the picture. Before colonization, this place I now sit writing was surrounded by extensive marshes. Eels thrived in low lying wetlands that extended the river deep into the landscape, obscuring the fixed boundaries we impose on the river today. Indeed, not just the banks and flood plains of the river were wetter than they are today, but the entire watershed, and indeed the entire region.6 The indigenous cultures of this place interacted with the wetlands (and the wildlife in them), and they may well have extended and enhanced them, much as indigenous cultures all over the world have enhanced landscapes to the mutual benefit of humans and their other-than-human kin.7
Much has been written about the nature of the relationship between indigenous people and the landscapes they inhabit, including by indigenous Native Americans themselves.8 This information is precious, and I cannot survey all of it here. But one account stands out to me as especially resonant with the critique I’ve offered here of the paradigm of scientific river management, and the extensive damming that it serves to justify.
In their book The Dawn of Everything, David Graeber and David Wengrow draw on the work of Indigenous North Americans, especially Huron-Wendat scholar Georges Sioui, to argue that the indigenous peoples of Northeastern North America had a “surprisingly consistent” critique of European institutions and culture. Indigenous people were struck—and horrified—by the unfreedom of the Europeans they encountered. According to contemporaneous accounts summarized by Graeber and Wengrow, it was generally true in those indigenous North American cultures that “no one’s will” should be “subjugated to that of anyone else.” And this norm of noncoercion in turn favored a particular constellation of traits and habits—among them intelligence, respect, and cooperation.
Does this distinctive conception of the relations between people extend to the relations between people and wildlife, and between people and a river? Other indigenous writers tell us that it does, because wildlife are kin, and waterbodies are alive. Here is Robin Wall Kimmerer
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