Construction began on this dam in 1970, it was completed in 1974 and it was filled and put into use by 1976. This dam is a 1.7mile wide earthen embankment reaching a maximum height of 93 feet. It was constructed to create a reservoir for Columbus and is still one of three main reservoirs serving the area.
Though Alum Creek itself is really rather small, this dam created a lake about 11 miles in length, with a surface area of around 3,387 acres. The lake is surrounded by an addition 5,338 acres of state park land. The reservoir holds approximately 26.7 billion gallons of water, and supplies the nearby areas with up to 40 million gallons of water each day. The reservoir is supplied by 123 square mile watershed.
The dam has created a great recreation area, which is very popular for boating, fishing, hunting, hiking, and swimming. Alum Creek Lake features a 3,000 foot long beach, which is the longest inland beach in Ohio.