Book Description

Tests were conducted on two models of the Lock and Dam 26 spillway to determine discharge characteristics of the spillway, stilling basin performance, riprap requirements downstream from the structure, and gate vibration tendencies. The proposed gated structure, consisting of ten 110-ft-wide bays, will replace the existing dam. Tests to determine discharge characteristics revealed that data obtained in a previous model investigation could be used to determine discharge coefficients for the Lock and Dam 26 project. The stilling basin as originally designed resulted in unsatisfactory performance with only one gate open full. Several modifications to the basin were tested in an effort to effect better energy dissipation and spread flow downstream during single-gate operations. A stilling basin that resulted in satisfactory flow conditions was developed. Tests to determine the riprap requirements in the exit channel indicated that the protection will be needed for a distance of 1200 ft downstream from the basin. A protection plan was also developed. (Modified author abstract).