The value of the dam was particularly proven during the Great Flood of 1993, when floodwaters reaching up to 63 feet (19 m) above normal were held back. However, when the dam reached capacity in July 1993, it necessitated the first release of the spillway since its installation. All 18 gates on the spillway were raised 4 feet (1.2 m) during the peak of the flood, producing a flow rate of 60,000 cubic feet per second (1,700 m³/s) (with the tubes closed at that time). While this controlled flow rate resulted in flooding of low-lying homes and cropland, it was significantly less than the estimated peak flow of the downstream communities would have experienced on June 30 had the dam not been in place, an amount that would have topped the Big Blue River Levee and flooded downtown Manhattan. The roar of the water was audible half a mile (800 m) away and some people in nearby Manhattan reported hearing the noise.