The navigation channel engineering poses optimal control problems of h
ow to find the optimal way of engineering such that the water depth of
the channel is maximum under certain budget constraint, or the cost o
f the engineering is minimum while certain goals are achieved. These a
re typical control problems of distributed system governed by hydrauli
c/sedimentation models. The problems and methods of solutions are disc
ussed. Since the models, usually complicated, are nonlinear, they can
be solved by solving a series of linear problems. For linear problems
the solutions are given. Thus the algorithms are simplified.