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 m ³ / 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
Great Flood of 1993
Great Flood of 1993
Tuttle Creek Lake