A canal and a river are two different issues. A canal is man made while a river is part of nature. The canals and not rivers you mention in Amsterdam were built to fit the human needs. That is why Suez and Panama Canals are canals and not rivers. A canal can be built to sumplement a river or where there is not water connection, a canal can be built.
Rivers are not diverted to avoid buildings but the other way round, buildings are built to avoid rivers.
oh dear...a drug baron gets yet another appointment
Dont know why people made fun of waititu when he said rivers can be moved. What he meant to say was rivers can be diverted like they do in Amsterdam and he'd actually been to Amsterdam and studied their technology, but kenyans are so stupid they have a hard time following basic arguments.