Book excerpt: A replacement lock is planned for the Inner Harbor Navigation Canal (IHNC) Lock in New Orleans, LA. The existing 675-ft-long by 75-ft-wide lock with a floor elevation of -36 ft referred to the National Geodetic Vertical Datum (NGVD) will be replaced with a 1,200-ft-long by 110-ft-wide lock with a floor elevation of -40 ft NGVD. The design lift for the new lock is 19.6 ft, and it will handle both deep- and shallow-draft vessels. A 1:25-scale physical model study of the proposed design was performed to verify the hydraulic design. The initial design consisted of an end filling and emptying system with sector gates. The sector gates were selected because of the reverse lift conditions that occasionally occur at the project. Guidance for this type design and lift for a deep-draft vessel was essentially nonexistent. There was concern that the end filling system might be too slow to maintain safe filling operations for this lift. A side port system was selected as the alternate system to evaluate during the study. The initial end filling and emptying system design proposed was 1,360 ft long from pintle to pintle and allowed for additional lengths at the ends of the chamber for energy dissipation. Both filling and emptying systems were evaluated with this length of lock. Normal lift conditions between 3 and 19.6 ft and a reverse lift of 9 ft were evaluated for selected valve operations. Excessive filling times were determined for the end filling and emptying system with shallow-draft vessels. With a deep-draft vessel and the end filling and emptying system, the accepted hawser force criteria could not be met with lifts greater than 3 ft even with extremely slow gate opening operations. The side port system was faster and the hydraulic conditions were more desirable. The side port system was chosen for further evaluation and the pintle-to-pintle lock length was reduced to a more conventional 1,270 ft (Type 2 design lock).