Germantown Dam is a dam located near Germantown, Ohio in Southwest Ohio. It is an earthen dry dam that regulates the flow of Twin Creek into the Great Miami River to prevent downstream flooding. It consists of 865,000 yd³ (661,000 m³) of earth, is 100 feet (30 m) high and 1210 feet (369 m) wide. The dam can hold back 73,000 acre feet (90,000,000 m³) of flood water over its 2950 acres (12 km²) of basin. It was constructed in 1920 using fill trestles. The dam's waterproof impervious core consists of a mixture of clay and sand known as hydraulic fill that was mixed using a sluice. This core is stabilized on each side by a bank of sand and gravel. The dam was constructed and is maintained by the Miami Conservancy District.