Not to deter from your point, but said basement was far far above the water line and even above the flood wall. And different placement would have been more ris

Not to deter from your point, but said basement was far far above the water line and even above the flood wall. And different placement would have been more risky for earthquake damage. The failing was the insufficient flood wall, which TEPCO very definitely knew about, with almost exactly this scenario predicted, not the placement of backup generators.