Modifications to Filling and Emptying System of Lock Number 1, Mississippi River, Minneapolis, Minnesota; Hydraulic Model Investigation

摘要

The existing locks at Locks and Dam No. 1 were constructed between 1929 and 1932. Problems have been experienced with accumulation of ice and debris at the intakes, air entrapment in the the culverts of the filling and emptying system, excessive turbulence in the lock chamber during filling, and hazardous conditions downstream from the locks during emptying operations. Also, the stoney gates used for control of filling and emptying, the miter gates, and miter gate operating machinery are in bad condition. Various elements of the filling and emptying system were developed in a 1:25-scale hydraulic model for use in rehabilitating the locks. Both the landward and riverward locks were investigated and recommended design and modifications were furnished to accomplish rehabilitation of both locks although only the landward lock will be completely rehabilitated. Major modifications to the locks will include constructing new intake manifolds, lowering the roof of the filling and emptying culverts and changing their shape, constructing new sidewall ports, replacing the stoney gates with tainter valves, and constructing new culvert outlets. With the rehabilitated system, the lock could be filled in 10.2 min and emptied in 10.6 min with a 4-min valve time and a 37.8-ft lift. (Author)