Garza Little Elm Dam Spillway construction in Lewisville, Texas Dec. 9, 1952 The W.E. Callahan Construction Company completed the Garza Dam in 1927 at a cost of $5 million, which created Lake Dallas. The dam was 10,890 feet (3,320 m) long with a 567-foot (173 m) long service spillway. The lake, with its 194,000-acre-foot (239,000,000 m3) capacity and forty-three miles of shoreline, was the principal municipal water source for the city of Dallas for 31 years.