So let's examine your premise that one of the ways in which evangelicals misinterpret God's word concerns the extent and impact of the flood. This is Genesis 6:13:
Gen 6:13 writes:
And God said to Noah, "I have determined to make an end of all flesh; for the earth is filled with violence through them; behold, I will destroy them with the earth."
God continues in Genesis 6:17:
Gen 6:17 writes:
"For behold, I will bring a flood of waters upon the earth, to destroy all flesh in which is the breath of life from under heaven; everything that is on the earth shall die."
God describes how many of the world's animals must be taken on the ark in Genesis 6:19:
Gen 6:19 writes:
"And of every living thing of all flesh, you shall bring two of every sort into the ark, to keep them alive with you."
God describes again how much life he will destroy in Genesis 7:4:
7:4 writes:
"For in seven days I will send rain upon the earth forty days and forty nights; and every living thing that I have made I will blot out from the face of the ground."
In Genesis 7:19 the extent of the decimation is described:
Gen 7:19 writes:
And the waters prevailed so mightily upon the earth that all the high mountains under the whole heaven were covered; the waters prevailed above the mountains, covering them fifteen cubits deep. And all flesh died that moved upon the earth , birds, cattle, beasts, all swarming creatures that swarm upon the earth, and every man; everything on dry land in whose nostrils was the breath of life died. He blotted out every living thing that was upon the face of the ground, man and animals and creeping things and birds of the air; they were blotted out from the earth.
Heck of a mistranslation if the flood wasn't global wiping out all life except that saved on the ark.
--Percy