Mill River Dam Disaster

The Mill River flood was the first major dam disaster in the United States and one of the greatest calamities of the nineteenth century. It happened early one May morning in 1874, in the hills above the western Massachusetts towns of Williamsburg and Northampton, when a reservoir dam (used for waterpower) suddenly burst, sending an avalanche of water down a narrow valley lined with factories and farms. Within an hour, 139 people were dead, and four mill villages were washed away.

The Mill River flood instantly became one of the nation’s big news stories. Newspapers and magazines recounted survivors’ daring escapes from the floodwaters and described the horrors of the week-long search for the dead among acres of debris.  Investigations showed that the dam had collapsed because it was poorly and negligently constructed, but, like many other disasters of the nineteenth century, no one was held accountable. The flood’s legacy was that it prompted Massachusetts, and nearby states, to grasp the hazards of unregulated reservoirs and to pass landmark dam safety laws.

The Mill River is a slim rocky stream, just fifteen miles long, that tumbles down the foothills of the Berkshires into the Connecticut River.  By the mid-nineteenth century, it powered small-scale industries that made brass goods, grinding wheels, silk thread, buttons, and cotton and woolen fabrics. As the century wore on, the Mill River manufacturers, like their counterparts around New England, required more water to sustain profits. Increased flow allowed them to scale up production to stay competitive in the nation-wide marketplace created by railroads. And, it enabled them to counteract the effects of upstream deforestation as eroding soil washed downriver and silted in mill ponds thereby reducing water storage capacity at the mills. The solution was to build an upstream storage reservoir which could be tapped as needed to provide a steady flow to the factories downstream. Thus, in 1864, eleven manufacturers formed the Williamsburg Reservoir Company to dam the upper reaches of the Mill River in Williamsburg. Completed in 1866, the earthen embankment dam consisted of a stone wall (meant to keep the dam watertight) supported by massive banks of packed earth.  It stretched 600 feet between hillsides and rose 43 feet above the river. The reservoir covered 100 acres. More details