Thousands of Americans Perished in This Horrific Dam Failure

Dams are a crucial and key part of the nation’s infrastructure. They provide control over water bodies, controlling flow and creating storage options. In the U.S., there are more than 90,000 dams, and while carefully built, they also carry inherent risks, particularly of failure. If a dam has a high risk potential rating, it doesn’t mean it’s at high risk of failing but rather that if it did fail, it could be catastrophic — lives lost and massive amounts of damage.

Dam Failure Rates

Dam failures, while rare, do happen. According to the National Performance of Dam Failure report , an average of 24 dams fail every year in the United States. Over the past four decades, there have been approximately 1,000 dam failures, killing 34 people. And with so many of our nation’s dams being more than a half-century old, many are starting to show their age in wear and tear.

The Most Catastrophic U.S. Dam Failure in History

South Fork Dam was located in the town of Johnstown, Pennsylvania. A rock-and-earthen dam, it was originally constructed in 1852. It was 918 feet in length, 72 feet in height, 10 feet in width at its crest, and 220 feet in width at its base, and it was designed to be a water source for a canal. Its failure, however, is still considered the most devastating dam failure in American history.

Where Is Johnstown, PA?

Johnstown, Pennsylvania is located 57 miles east of Pittsburgh and is the principal city of the Johnstown metropolitan area, which includes Cambria County. The Johnstown Flood Museum offers visitors an opportunity to view artifacts, photos, and information concerning the devastating flood of 1889.

Concerns Were Raised — but Ignored

During the 1880s, the dam had periods of leakage, and to repair it, mud and straw were applied to stop the leaks. Concerns, however, were raised about the potential for dam failure and what that would mean for the nearby city of Johnstown.

Concerns About the Dam Grew

Though residents raised their concerns, they were dismissed. There had also been several false alarms about the dam failing that didn’t come to light, so the people to whom residents complained had further reason not to pay mind to the concerns. However, when the rain started coming down in May 1889, people grew concerned.

The Rains Came Down

As the incessant rain poured over the dam, the structure gave way, and on May 31, 1889, 20 million tons of water flooded Johnstown. As the water flowed through Johnstown, it reached a sturdy stone bridge, but because the bridge was so sturdy, the water didn’t wipe it out and keep going. Instead it flowed back into the town. Buildings were destroyed and more than 1,600 homes were lost as well. Sadly, more than 2,200 people lost their lives that day, and those who survived were left to deal with over $17 million in damage.

A Fire Added Insult to Injury

In addition to the flood, a massive fire broke out further destroying an already decimated town.

What Caused the South Fork Dam Failure?

The South Fork Fishing and Hunting Club was largely regarded as the reason the dam failed. They had utilized the dam for their own enjoyment, making changes to accommodate their own desires, such as adding fish screens across the spillway to ensure the water was stocked. Those changes created a risky situation that ultimately played out as the residents feared it would. of the dam’s failure. The owners of the club made changes to the dam for the enjoyment of their private members.

Poor Building Decision Were Made

Rustic cottages were also erected close to the relief pipes and valves that managed the water level and spill-off from the original dam. The club never erected the drainage pipes again, preventing the reservoir from being drained. All of these modifications contributed to the leaks that compromised the integrity of the dam.

A Wall of Water

South Fork, Mineral Point, Woodvale, and East Conemaugh were utterly destroyed by the torrent of 4.8 billion gallons of water (a little over 20 million tons) and debris in just 10 minutes. The mass of wreckage was a wave 45 feet tall, over a half mile wide, and moving at 40 miles per hour by the time the roaring waters hit Johnstown.

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