Do We Have Enough Water to Flood the Whole Earth?

A guest post by John Hudson Tiner, who has written a number of books published by Master Books (I particularly enjoyed his book on Physics–I’m not scared of it any more!). First published August, 2013.

Bible doubters like to point out how crazy it is to imagine all earth’s mountains covered with water, but all geologists believe they were. The difference is whether we believe it all happened at once or over “millions of years”.
Another piece of the puzzle is if earth has enough water to cover the whole world at the same time or not. Solving this uses a lot of math, which I’m not too excited about, so all I’d ever seen were the conclusions Creationists had come up with.
Enter our guest writer. Saturday, I spotted this little gem of mathematics he’d posted and loved how factual and “simple” it made the whole problem. Since he was taking questions on a live expert forum, I could ask him if it was OK for me to share with you all. Mr. Tiner kindly granted my request.
So, here’s what he has to say about the amount of water on earth [for metric users: 8,000 feet equals 2438.4 meters]:

. . . Now to the depth of the water during the flood. Dr. Morris says that it has been calculated that on a smooth spherical earth the water would cover the earth to a depth of 8,000 feet.
That is easy enough to check (provided I remember to use radius of earth rather than diameter!)

• Radius of earth in miles: 3,963 miles
• Thickness of 8,000 feet of water in miles: 8,000 ft/5280 ft/mi = 1.5 miles
• Volume in cu mi of a smooth, spherical earth with a 1.5 mile thick layer of water:
  (4/3)pi*r^3 = (4/3)pi(3,963 + 1.5)^3 = 261,008,000,000 (rounded to nearest million)

Volume in cu mi of a smooth, spherical earth without the layer of water:
(4/3)pi*r^3 = (4/3)pi(3,963)^3 = 260,711,000,000 (rounded to nearest million)

The difference (261,008,000,000 – 260,711,000,000 ) is the amount of water to make:

A layer of water 1.5 miles thick: about 296 million cubic miles of water.

This site, The USGS Water Science School, How Much Water is there on, in, and above the Earth? shows the total amount of water to be 338 million cu mi. That figure agrees with one I read in an old-fashioned world almanac about 30 years ago.

Give unto the LORD, O ye mighty, give unto the LORD glory and strength.
Give unto the LORD the glory due unto his name; worship the LORD in the beauty of holiness.
The voice of the LORD is upon the waters: the God of glory thundereth: the LORD is upon many waters.
The LORD sitteth upon the flood; yea, the LORD sitteth King for ever. Psalm 29:1-3,10