A relative measure of flood productivity. It is a numerical factor used to compare extreme floods on different streams, given by the extreme discharge (in cubic feet per second) on a stream divided by 100 times the square root of the drainage area (in square miles). Typical values in the eastern United States range from 30 to 40, but values as low as 1 or 2 occur in the Great Basin, and some as high as 300 occur on some basins in west Texas.