On May 16, 1874, the cheap and shoddy Mill River dam collapsed, killing 139 people and wiping out four towns in western Massachusetts within one hour.
It was the first manmade dam disaster and one of the worst of the 19th century.
Though mill owners and engineers were clearly responsible for the disaster, no one was held to account for it. But at least the flood did lead to dam safety laws.
The Mill River is a 15-mile-long stream that drops 700 feet from the high hills of the Berkshires to the Connecticut River. During the 19th century, manufacturers built a string of mills along the river to take advantage of the cheap power. Factories made silk thread and woolen cloth, brass goods, grinding wheels and buttons.
By the 1860s, mill owners realized they could build reservoirs to maintain enough flow during the dry summer months.
In 1864, 11 manufacturers formed the Williamsburg Reservoir Company to dam the Mill River in Williamsburg.
They wanted to save money, so they designed and built the dam themselves. During construction, they cut corners over the protests of the surveyor and workers. They feared the poorly built dam would endanger the people who lived downstream.
Work on the dam finished in 1866. Six hundred feet long and 43 feet high, it had earthen embankments supporting a stonewall. The massive structure held back a 100-acre reservoir.
On May 16, the reservoir was already full, and it rained in buckets. At 7 a.m., George Cheney, the dam keeper, saw a 40-foot slab of earth slide off the face of the dam. The earthen bank began to crumble as streams of water started pouring through holes in the dam.
The stone wall had been grouted poorly. Water from the reservoir leaked through the cracks and saturated the downstream earthen bank.
The dam keeper knew what would happen next. Without the support of the earth embankment, the stonewall couldn’t withstand the pressure of the reservoir.
George Cheney frantically jumped on his horse bareback and galloped downstream to warn the people of Williamsburg.
As he shouted warnings, the dam burst with a tremendous boom that filled the valley. Farmers miles away said it was louder than any thunder they had ever heard.
Four men relayed the dam keeper’s warning, racing ahead of the floodwater in wagons and on horseback. They were first able to warn the factory workers, most of whom escaped. Next they tried to warn people in their homes – women, children, old people.
The breach opened wider and 600 million gallons of water roared through the valley, a 40-foot-high wall of water carrying with it roofs, boulders, livestock, timber, furniture and people.
Survivors began to search for the dead as soon as the flood subsided. The government had no disaster relief programs then, so local committees organized thousands of volunteers to handle cleanup and relief. They raised $100,000, an enormous sum that rivaled the donations for the victims of the Great Chicago Fire three years earlier.
The Massachusetts state government eventually stepped in to loan $120,000 to rebuild the valley’s infrastructure. The loan helped restore all the towns but Skinnerville, though they never returned to their former prosperity.
The state Legislature also passed the first dam safety law, and neighboring states followed Massachusetts’ example.
With thanks to In the Shadow of the Dam: The Aftermath of the Mill River Flood of 1874 by Elizabeth M. Sharpe. This story about the Mill River Flood was updated in 2021.