Stevenson Dam Hydroelectric Plant National Register of Historic Places Listing

Workers poured the concrete in 1917. While the United States plunged into World War I, the Connecticut Light and Power Company scrambled to meet the sudden, desperate energy demands of booming munitions factories in Bridgeport and New Haven. A massive undertaking. Engineers threw a concrete gravity dam across the Housatonic River, spanning 1,213 feet and rising 125 feet from the riverbed to tame the wild waters. They did something weird, though. Instead of just building a wall to hold back water, they slapped Route 34 right along the top of the spillway structure, combining a crucial highway bridge with a massive power generator.

Inside the powerhouse, heavy iron ruled. Workers installed four S. Morgan Smith vertical waterwheels and hooked them up to massive General Electric generators that instantly cranked out 28,750 kilowatts of electricity. This wasn't just about lighting living room lamps, as the cheap juice fed the brass mills down in Waterbury and the rubber plants in Naugatuck. It fueled raw industrial growth. The resulting reservoir, Lake Zoar, swallowed up old farmsteads and changed the local geography forever, but it secured the state's industrial dominance for decades. It still works. Even now, after a century of wear and tear, the plant continues to feed power into the New England grid.