Developing a lock operation strategy for pool lowering

The pool lowering capability of Locks and Dam I, Mississippi River, can be increased if the lock filling and emptying system is used as a discharge outlet. However, the steady state conditions of passing flow through the lock system and the conditions during the acceleration to steady state can include excessively low pressures downstream of the filling and emptying valves. A lock valve operation scheme that provided acceptable flow conditions in the lock system was developed using a numerical flow model of the lock filling and emptying systems coupled with commercial optimisation software. The flow model was validated with field data obtained at the Lock I prototype. The resulting modelling system determined the optimum valve operations to obtain steady state conditions and provided the head–discharge relationship for the lock.