Is a blessing recited on a river (or sea) whose course has been humanly altered or redirected?

Synopsis

All authorities agree that a blessing is only recited where the river/sea remains in its original primordial state. Where humans have dug or redirected the waterway, it is no longer 'ma'aseh bereshit' and no blessing is said.

Early Acharonim
Late Acharonim
Lenient
Strict
Lesser cited
Major authority

Discussion

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