If simple engineering sounds like religion to you, then your positions are understandable.  It is true, as ordained by GOD that moving water carries kinetic energy which can be converted via simple electromagnetic mechanisms involving rotating fans and electric induction into clean electric power.  If by design, a river's flow is only partially harvested (as would happen if a downed tree were to become lodged in rocks partially impeding river flow) little substantial impact on the river would derive.  Ordinarily, the energy released by return of water to the sea is dissipated as heat in turbulence as the water gushes here and there and interacts with its bed.  Simple engineering design includes deflective screens to protect fish.  Appropriate placement and spacing protects against slit deposition and accumulation.  

Your rejection of such an obvious 24/7 source of energy is amazing.  Look in the mirror and realize that you do not support control of AGW on any terms but your own.