Saylorville Lake is a reservoir on the Des Moines River in Iowa. It is located 11 miles upstream from the city of Des Moines, and 214 miles from the mouth of the Des Moines River at the Mississippi River. It was constructed as part of a flood control system for the Des Moines River as well as to aid in controlling flood crests on the Mississippi, of which the Des Moines is a tributary.
At its normal level of 836 feet above sea level, Saylorville Lake covers an area of 5,950 acres or 9.3 square miles and reaches some 17 miles upstream. At full flood stage the lake can reach 16,700 acres or 26.1 square miles and reach 54 miles long. At this point any further flow into the lake is channelled over an emergency spillway to the west of the main dam structure. The record high stage for the reservoir was 892.03 feet above sea level set on July 11, 1993 during the Great Flood of 1993.
Construction of the Saylorville Dam was authorized by Congress in 1958. Excavation began at the site in July 1965, becoming fully operational in September 1977. The dam itself is 6,750 feet long, 105 feet tall, and 44 feet wide at the top.