Walter Bradley wrote a section about whether the Flood of Noah was local or global in his chapter “Why I Believe the Bible Is Scientifically Reliable” in the book Why I am a Christian: leading thinkers explain why they believe (pp. 177–180) [Grand Rapids, MI: Baker Books (2001)]. Both the title of his chapter and the introductory paragraph below tell about his approach. His arguments are based on the Biblical text:
The flood of Noah is one of the greatest events of Genesis 1–11, and, like young earth creationism, is the source of considerable scorn regarding the reliability of the Bible. But as with the question of the age of the earth, the controversy here is unnecessary if one reads and interprets the passage carefully. The fundamental question is whether the Noachian flood was global or local.
Walter acknowledges that the terminology in Genesis 6-9 seems to favor a global flood, specifically pointing out about the “all the high mountains under the whole heaven were covered (Ge 7:19, ESV).” He will discuss the Hebrew word translated covered later. He goes on to discuss how the Biblical language in the Flood story is used elsewhere in the Bible:
In Genesis 41:56, we are told, “The famine was spread over all the face of the earth” (NASB). We normally interpret this famine as devastating the lands of the ancient Near East around Egypt and do not assume that American Indians and Australian aborigines came to buy grain from Joseph. First Kings 10:24 states that “the whole world sought audience with Solomon to hear the wisdom God had put in his heart.” Surely Inca Indians from South America or Maoris from New Zealand had not heard of Solomon and sought his audience.
Then Walter goes on to explain the Hebrew word אֶרֶץ:
The Hebrew word erets used in Genesis 7:19 is usually translated “earth” or “world” but does not generally refer to the entire planet. Depending on the context, it is often translated “country” or “land” to make this clear. References to the entire planet are found in Genesis 1:1; 2:1; and 14:22, for example. However, more typical references might be Genesis 1:10; 2:11; or 2:13, where erets is translated “land.” In Genesis 12:1, Abram was told to leave his erets. He was obviously not told to leave the planet but rather to leave his country. Genesis 41:56 describes the famine as being over all the face of the erets, which could be translated “land,” “country,” or (entire) “earth.” Obviously, the famine did not literally cover the entire earth. Again, in Exodus 10:5, 15, we are told the locusts covered the surface of the erets. Translating erets as “earth” here would not make sense. We see once again, as with the Hebrew word Yom, that the small and limited vocabulary of the Hebrew language requires that many Hebrew words have multiple meanings, with the actual meaning determined by the context. A final helpful comparison to obtain a proper interpretation of Genesis 7:19 involves Deuteronomy 2:25, which talks about all the nations “under the heavens” being fearful of the Israelites. Obviously, all nations “under the heavens” was not intended to mean all on planet Earth.
The strongest argument for a global flood is the Hebrew word כסה translated covered in Genesis 7:19. Here he discusses the meaning of that word:
The Hebrew word translated “covered” in Genesis 7:19 is kasah. It can mean “residing upon,” “running over,” or “falling upon.” Twenty feet of water running over or falling upon the mountains (or hills) is quite different from that amount residing upon them, although either event could destroy human and animal life in its path. The Hebrew word har translated “mountain” in most English translations of Genesis 7:19 also means “hill” or “mount.” Thus, we might as easily translate Genesis 7:19 to say that “all the high hills in the region of the Mesopotamian valley were covered with water to a depth of more than twenty feet.” This is very different from the usual rendering that “all the highest mountains on the earth were covered with water to a depth of twenty feet.”
Here Walter argues that all the human population of the earth may have been in one location at the time of the Flood:
In Genesis 1–9, the only geographical references are to the region of Mesopotamia. If the ancestors of Noah had elected to stay in this general region rather than spread throughout the earth as God had commanded, then God’s judgment would require only a flood in this region, and this appears to have been the case.
Here Walter gives more details in the Biblical account that make sense with a local flood:
If the entire Mesopotamian valley was flooded and the water receded slowly, then Noah might have seen only water, with distant mountain ranges being over the horizon. God’s use of wind in Genesis 8:1 to cause the flood to subside would be reasonable for a local flooding of this huge valley. It would not make sense for a flood that left water to a depth of thirty thousand feet, sufficient to cover Mount Everest. Genesis 8:4 indicates that the ark came to rest on the hills or mountains of Ararat, not specifically Mount Ararat, which is seventeen thousand feet tall. This complex mountain range extends north and east of Mount Ararat down to the foothills skirting the Mesopotamian plain. If the ark had landed near the top of Mount Ararat, it is difficult to imagine how Noah and his family as well as the animals would have been able to descend to the base of the mountain, given the considerable difficulty mountain climbers have today attempting to reach the locations where the ark is thought (I believe, incorrectly) to have landed.
Further evidence for a local flood is found in Genesis 8:5, where it is noted that the water receded until the tenth month when the tops of mountains (or hills) became visible for the first time. The reference here seems to be what Noah could see, not the entire world. In Genesis 8:11, the dove returns with an olive leaf. Since olive trees don’t grow at higher elevations, a flood that covered all the mountains would not give this type of evidence of receding.
Here Walter mentions the problem of the amount of water necessary for a global flood to cover twenty feet over Mount Everest:
One can estimate the total amount of water that would be needed to cover all the mountains on the face of the earth and compare this to the total water reserves that we know of on planet Earth, both in lakes and oceans and in subterranean aquifers. A flood that covered all the mountains on earth would require 4.5 times the total water resources that exist on planet Earth. Furthermore, such a worldwide flood would be pointless if the descendants of Adam lived only in the region of Mesopotamia.
While scientific evidence does not support a global flood, here Walter sites scientific evidence supporting an local flood:
While scientific evidence for a worldwide flood is clearly missing, there is considerable evidence from both geology and archaeology of one huge and several smaller floods in the region of Mesopotamia during the time period of the Noachian flood. Fredrick A. Filby, in The Flood Reconsidered, summarizes his chapter on this topic as follows:
Some time after the Ice Age and before the rise of the great dynasties, a great flood caused by either a close approach of some heavenly body, or by the movement of the continents, or both swept from the Atlantic, the Mediterranean, and the Indian Oceans over much of Europe and Asia. During this period Paleolithic man disappeared, the entire climate of Siberia was radically changed, herds of mammoths were completely eliminated, some being apparently almost instantaneously frozen to death by unprecedented cold, and the sabre-tooth tiger, the woolly rhinoceros and a hundred million other creatures perished. Herds of animals in Europe and Western Asia were trapped by rising water and many were dashed to pieces, their bones being swept into great cracks, which had appeared in the earth. Lesser risings and fallings of certain local areas have continued, giving rise to raised beaches, shifting levels of fens in England, or various flood levels in Mesopotamia, but these are obviously small compared with the event which drowned a hundred million animals and exterminated an ancient race of men. The great oceanic tide, accompanied in the Middle East by torrential rain, and in Siberia by intensely frozen snow, capable of floating and indeed of driving a 10,000 ton wooden barge, probably from Mesopotamia to the regions of the mountains (or hills) of Ararat … that Flood which Genesis describes so minutely, was surely unique in history, and, by the promise of God was not to be repeated—and in fact, never has been.
It should be noted that Filby’s account, which was completed before 1970, would place the flood between four thousand and ten thousand years ago, but after the last ice age. Hugh Ross’s more recent treatment of this topic would place it somewhat earlier, with humans bridging the Bering Sea to populate North and South America about eleven thousand years ago, before the ice melted and the sea levels rose. This would put Noah’s flood between probably ten thousand and twenty thousand years ago.
So Walter Bradley argues that a local flood is supported by both the Biblical account and scientific evidence. A young earth creationist is more likely to believe Noah’s Flood was global, while an old earth creationist (e.g. Hugh Ross, whom he references) is more willing to believe Noah’s Flood was local.
Hugh Ross’s discussion is at https://www.reasons.org/explore/blogs/todays-new-reason-to-believe/read/todays-new-reason-to-believe/2016/11/02/does-the-bible-say-noah-s-flood-was-global-or-universal . Hugh does not use the term local. He states:
I believe the flood of Noah was universal but not global. By universal, I mean that the entire human race and all of the nephesh (soulish) animals associated with humans were wiped out by the flood except for those humans and animals that were on board Noah’s ark.
Hugh Ross also has chapter 18, “The Flood: Global or Local? Genesis 7-8,” in his book, The Genesis question: scientific advances and the accuracy of Genesis. This is an extensive chapter from page 145 to 161.