 Planning for the reservoir began as early as 1913, when hydraulic engineers estimated that White River and Fall Creek would not provide enough water for the increasing needs of Indianapolis.Geist gradually bought some in the Fall Creek Valley in the 1920s and 1930s, including the small town of Germantown, which today lies at the bottom of the reservoir.Although controversial, the reservoir was completed in 1943, five years after Clarence Geist's death.