PDF Summary:The Emerald Mile, by Kevin Fedarko

In 1983, an El Niño event triggered a crisis at Glen Canyon Dam that nearly caused catastrophic flooding throughout the Southwest. In The Emerald Mile, Kevin Fedarko recounts how engineers raced to prevent disaster as unprecedented snowmelt threatened to overwhelm the dam's infrastructure. The crisis exposed fundamental flaws in the dam system and marked a turning point in the era of large-scale dam construction.

Fedarko also tells the story of a legendary speed run through the Grand Canyon during the flood, examining what the run meant to the river community and the broader conservation movement. Through these intertwined narratives, you'll learn about the mechanics of the 1983 flood, the engineering challenges of managing massive water flows, and the legacy of those who dedicated their lives to the Colorado River and Grand Canyon.

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(Shortform note: In recent years, the Great Salt Lake has receded to record lows, exposing vast areas of lakebed and raising concerns about dust storms and ecological damage. The lake's decline is attributed to prolonged drought and upstream water diversions, highlighting the region's ongoing struggle to balance water needs with environmental preservation.)

The tempests continued eastward. When they arrived in Colorado and struck the southern Rockies, it began snowing heavily and continued until the peaks were buried under a thick, icy blanket. Crested Butte in the Elk Mountain range experienced 45 straight days of snow. On March 10, a massive storm caused the snowpack in some areas of the southern Rockies to exceed 17 feet. Two days after, a more intense storm added two more feet to that. The storms caused the temperature to fall to below-freezing levels, postponing the beginning of spring melting. As April drew near, resorts between Salt Lake City and Denver were gearing up to extend the ski season beyond Memorial Day, with snow levels reaching 825 inches—three times the usual amount for that time of year.

Snowfall vs. Snow Depth

The “snow levels” here refer to the total snowfall over the season, not the depth of snow on the ground at any given time. This means that 825 inches of snow fell throughout the winter, but the actual depth of snow on the ground at any moment would be much less due to melting, settling, and compaction. For example, if a ski resort reports 825 inches of snowfall for the season, it doesn’t mean there’s a 68-foot-deep layer of snow on the slopes. Instead, it means that if you added up all the snow that fell over the entire winter, it would total 825 inches. The actual snowpack depth—the amount of snow on the ground at a specific time—would be significantly less, as some snow would have melted or compacted over time.

Impacts and Near-Failures

Fedarko notes that the debris flow of 1966 created a dangerous rapid at Crystal Creek, which later became the most lethal section of the Grand Canyon's white water. The flood close to Mile 98 was so substantial that the government had to update its topographic maps. The river became a quarter of its original width, its descent doubled, and it moved faster because of the floodwaters and debris fan. The river, which was originally 280 feet wide, narrowed to a 55-foot-wide channel, similar to a New York City street's width.

(Shortform note: A debris flow is a type of landslide that occurs when water-saturated soil and rock move rapidly down a slope or channel. Unlike a typical landslide, where rocks and soil tumble down separately, a debris flow acts more like a thick, muddy river, carrying everything in its path as a single, fast-moving mass. These flows can reach speeds of up to 35 miles per hour and carry boulders the size of cars. They often occur after heavy rainfall or rapid snowmelt, when water loosens the soil and creates a slurry that rushes downhill.)

Engineering Responses and Mechanics of Fluids

Fedarko notes that engineers faced challenges managing the water flow and structural soundness of the dam throughout the 1983 flood. They needed to decide whether to use a damaged spillway or raise the volume through another channel, and either option risked further damage. Ultimately, they managed to contain the crisis by maintaining the tunnels used for spillways and using plywood flashboards to stop the reservoir from overtopping. Spillway repairs began in late August, and a cavitation specialist created air slots to counteract cavitation, effectively preventing future damage. The repairs exceeded $32 million, but the emergency generated $35 million more in hydropower. However, the total cost, including damage to the lower Colorado, was over $80 million, and several people drowned in the floodwaters.

(Shortform note: To decide whether to use the damaged spillway or raise the volume through another channel, engineers should use a risk-informed decision-making framework. This approach weighs the likelihood of failure and the potential consequences of each option. For example, using the damaged spillway might increase the chance of structural failure but reduce downstream flooding, while diverting water through another channel could lessen dam stress but increase flood risk. By quantifying these trade-offs, engineers can make more informed choices that balance immediate safety with long-term consequences.)

Fedarko argues that the reservoir and dam system is fundamentally flawed because it tries to meet competing demands: storing water, generating power, and controlling floods. The dam remained safe, but the spillway situation was riskier than it should have been.

(Shortform note: Many dam engineers disagree with Fedarko’s claim that the reservoir and dam system is fundamentally flawed. In Water Resources Systems Planning and Management, Daniel P. Loucks and Eelco van Beek argue that multipurpose reservoir systems can be optimized to balance competing objectives like water supply, hydropower, and flood control. They emphasize the importance of clear objectives, performance measures, and trade-off analysis to achieve efficient and sustainable operation.)

In this section, we’ll discuss the damage mechanisms that compromised the structure's integrity, and the engineering interventions that helped mitigate the crisis.

Damage Mechanisms and Structural Failure

Fedarko explains that cavitation damage threatened the dam's structural integrity. The damage occurred at the joint where the structure was weakest. This could have caused tunnel collapses or debris blockages, which would have prevented the dam from holding back the lake. The lake could have risen uncontrollably, overtopped the structure, and caused a disaster that would limit itself. The harm could have also worn away the concrete plug's surrounding sandstone, causing the abutment to give way. This would have opened a direct path to the reservoir, causing its contents to rush through the hole.

Cavitation Damage

Hydraulic engineers have studied cavitation damage in detail, and their findings support Fedarko’s claim that cavitation can threaten a dam’s structural integrity. Cavitation damage can erode concrete and rock, reducing a dam’s safety margins. The damage can progress from surface pitting to deep gouges, compromising the structure’s integrity. The damage can also create weak points that can lead to catastrophic failure. The damage can also create debris that can block spillways and other critical infrastructure. The damage can also create vibrations that can further weaken the structure.

Engineering Interventions and Mitigation Strategies

Fedarko explains that engineers implemented repairs and improvements to the structure in order to prevent future damage. The repairs cost $32 million, but selling the extra hydropower produced amid the crisis offset the cost, earning $35 million. The repairs involved swapping the plywood panels for steel bulwarks, which increased the barrier's height twofold. They also installed air slots to counteract cavitation effects within the spillways. The slots added air bubbles to the flow, preventing cavitation from causing harm.

The Evolution of Dam Engineering

The repairs made to Glen Canyon Dam reflect a broader shift in dam engineering that began in the mid-20th century. In Hydraulic Structures, P. Novak and colleagues explain that early spillway designs relied on trial and error, but as dams grew larger, engineers began to use laboratory models to test their designs. This led to the development of features like air slots, which introduce air into the water flow to prevent cavitation damage. These innovations have become standard practice in modern dam-safety engineering.

The Emerald Mile and the Spirit of the River

Next, we’ll discuss the conservation efforts that have helped preserve Grand Canyon National Park.

Competing for the Spirit: Defiance, Conservation, and Legacy

Fedarko asserts that the Grand Canyon is a treasured national site, and its preservation is a significant conservation victory.

(Shortform note: Not everyone agrees that the Grand Canyon’s preservation as a national site was a significant conservation victory. In American Indians and National Parks, Robert H. Keller and Michael F. Turek explain that many Havasupai leaders view the creation of Grand Canyon National Park as the culmination of a long history of federal policies that transformed their ancestral homelands into a recreational landscape controlled by outside authorities.)

Here, we’ll explore the run’s symbolism and legacy.

The Run as Symbol and Legacy

Fedarko argues that the speed run became a symbol of unity and legacy for the river enthusiasts. It was viewed as honoring the Colorado River’s majesty and protesting the way it had been harnessed and sold. It also demonstrated the capabilities of a compact, solid-hulled vessel. No one using a dory, kayak, or raft has ever broken Grua's record. Four years after setting the record, Grua stopped using the Emerald Mile and began experimenting with boat design. He constructed two more dories, each one a step forward in innovation.

(Shortform note: As the Colorado River crisis has become more widely recognized, Grua’s run has taken on new meaning. In Science Be Dammed, Eric Kuhn and John Fleck argue that the real problem on the Colorado River is not an unforeseeable act of nature but the conscious decision by negotiators and water managers to ignore the best available hydrologic science. This has created a permanent structural deficit in which the “paper water” promised on contracts and compacts far exceeds the “wet water” the river can actually provide.)

He kept considering a vessel that would let him surpass his own record. He envisioned a long, thin vessel that would glide with ease and reach velocities unmatched by any dory. In 1988, Grua established Grand Canyon River Guides, which united all the canyon's boating community. The group's goal was to protect the canyon and river from harm by dam operators, helicopter-tour companies, and others. The group also organized yearly boatmen's gatherings, which ended with a canyon training trip for new river guides. Veteran boatmen from all companies offered guidance to the young guides, no matter what type of boat they piloted. As younger river guides embarked together, they forgot previous intense disputes, and everyone became friends.

(Shortform note: The Grand Canyon River Guides' mission to unite all the canyon's boating community and the camaraderie fostered during the canyon training trip are crucial for protecting the canyon and river from harm. When people work together and form strong bonds, they're more likely to collaborate effectively and advocate for the preservation of natural resources. Elinor Ostrom's work on commons governance shows that when communities come together and build trust, they can manage shared resources sustainably. By uniting the boating community and fostering friendships among guides, the Grand Canyon River Guides created a strong foundation for collective action to protect the canyon and river from external threats.)

Every summer, Grua kept piloting his dories on river excursions. He planned to keep going until he passed away within the canyon. However, in autumn 2002, as he was cycling, he experienced an aortic dissection and passed away. He was 52. His memorial took place in a meadow on a mountain just beyond the town. Everyone from the river community was there, and that evening they built a huge bonfire. Numerous attendees rose to speak about how remarkable he was. He left a significant emptiness behind. Steve Reynolds couldn't make it to the memorial.

(Shortform note: An aortic dissection is a tear in the inner layer of the aorta, the main artery that carries blood from the heart to the rest of the body. This tear allows blood to flow between the layers of the aortic wall, causing them to separate or dissect. This condition can be life-threatening if not treated promptly, as it can lead to a rupture of the aorta or decreased blood flow to vital organs.)

Shortly after the speed run, he bought a 37-foot sailboat and sailed to the South Pacific. He traveled to Fiji, Vanuatu, New Caledonia, Brisbane, New Guinea, Guam, the Carolines, Tinian, Saipan, Pagan, and Japan, including Okinawa. He was low on funds in Kyushu, but he secured a job as an English teacher. He married a Japanese woman named Noriko. They established an educational institution, had two kids, and made their home in a coastal town. Some years later, Reynolds decided to move his family to Hawaii, a U.S. state.

(Shortform note: A 37-foot sailboat can travel from the South Pacific to Japan and then to Hawaii by following the Pacific’s prevailing wind and current patterns. The journey typically starts in the South Pacific, where sailors use the trade winds to head northwest toward Japan. Once in Japan, the Kuroshio Current helps push the boat northeast along the coast. To reach Hawaii, sailors catch the westerly winds and the North Pacific Current, which carry them southeast across the ocean. This route forms a clockwise circuit that takes advantage of the Pacific’s natural wind and current flows.)

He lifted his anchor and returned across the Pacific. The voyage was arduous, but he eventually arrived in Hawaii, where he was reunited with his family. He enjoyed a life conducting boat trips to see humpback whales near Na Pali until a liver cancer diagnosis in 2010. He traveled to California for a transplant that was never received. In the last weeks before he died, he reunited with the author to reminisce about their high-speed journey. He passed away six weeks later. Rudi Petschek came to say goodbye. When Reynolds died, Petschek had also reluctantly stopped going on river trips.

(Shortform note: Reynolds’s later life and career trajectory, including his return to Hawaii and his work conducting boat trips to see humpback whales, is significant because it highlights a broader trend in the adventure tourism industry. According to Ralf Buckley’s Adventure Tourism, professional adventure guides often pursue serial, multi-environment careers, moving between river-running, backcountry trekking, and small-boat wildlife viewing along coasts and reefs. This occupational circulation creates a transnational guiding culture in which skills, safety practices, and interpretive styles are transferred from one activity sector and destination to another, progressively reshaping how guided adventure is designed and delivered worldwide.)

Following the speed run, he kept going for years, drawn back repeatedly by the longing that the canyon inspired. However, over time, his enthusiasm began to fade. Nearly two decades passed before the feeling of anticipation for the spring return eventually stopped happening the day after the final autumn trip. Initially, it dwindled to one week, then to several, until it disappeared.

(Shortform note: Environmental psychologists have studied how people form emotional bonds with specific places, a phenomenon known as “place attachment.” In Place Attachment, Irwin Altman and Setha M. Low explain that these bonds can change over time as people’s lives and identities evolve. This suggests that the author’s fading longing for the canyon may reflect a natural shift in his relationship with the landscape as his life circumstances changed.)