KJV - Whereby the world that then was, being overflowed with water, perished:

ASV - by which means the world that then was, being overflowed with water, perished:

BBE - And that the world which then was came to an end through the overflowing of the waters.

WEB - by which means the world that then was, being overflowed with water, perished.

YLT - through which the then world, by water having been deluged, was destroyed;

Notes